Nicolas Rieucau

Garat F Cramer

Approximately

Eliza Condorcet's Daughter

O'connor

CONDORCET'S SCIENCE OBSCURED: SHADOWS CAST BY THE ENLIGHTENMENT *

widow, Sophie de Grouchy, assisted by Barbier, Cabanis, C

from which it suffered at the time of his death as well as in the middle of the nineteenth century.

In addition, the reputation of his scientific work was undermined by his philosophical and political reflection, which emphasized the image of the Enlightenment writer and Republican who died for the French Revolution. 2

TWO INCOMPLETE EDITIONS

Despite all appearances, the twenty-one volume edition of 1804 is less complete than that of 1847-1849, which only contains twelve volumes. Nonetheless, both editions exclude Condorcet's scientific works and most of the newly published texts in the second edition are philosophical or political. Before clarifying the selective process of these two editions, I should specify that I will consider these aspects essentially without taking into account Condorcet's original manuscripts. Faithful to the editorial policies commonly practiced in the nineteenth century, those responsible for the 1804 and 1847-1849 editions neglected this type of manuscript whatever its editorial stage (preparatory notes, plans, rough drafts) and whatever its purpose (scientific, philosophical, political, or economic). These omitted texts would have added at least another two-thirds to the size of the two editions. Thus, the exclusion of a certain number of Condorcet's autograph manuscripts does not specifically illustrate the discarding of his scientific work. In order to clarify the editorial decision to set aside Condorcet's scientific texts, I will focus on printed works or fair manuscript copies.

The Edition of 1804

As a manuscript note recorded by Wilhelm von Humboldt in December 1798 reveals, a section devoted to mathematics was initially to have been one of the components of the 1804 OEuvres. [START_REF]Relevé des manuscrits qui m'ont été communiqués par Mme Condorcet[END_REF] The Catalogue des ouvrages de Condorcet, a 1797 text establishing the Condorcet corpus, [START_REF]Written around 1797[END_REF] indicated the following divisions: Basically it is a text on political arithmetic, comprising the "Third Part" (1785) of the Mémoire sur le calcul des probabilités (1784-1787). The second text is the Tableau général de la science qui a pour objet l'application du calcul aux sciences politiques et morales (1793). The Journal d'instruction sociale, in which this text appeared, is included in the division "Philosophical literature," 7 but the text in question, as its title suggests, presents Condorcet's works in social mathematics.

The Catalogue omits many of Condorcet's other mathematical texts. Among printed works or fair manuscript copies, the following texts were left out: The 1804 OEuvres thus consciously neglect Condorcet's scientific works, while, by contrast, the absence of several texts relevant to the political or moral sciences was due in particular to the editors' difficulties in obtaining them. 9 The Eulogies delivered by Condorcet to the Academy of Sciences, which make up two of the ten volumes of the "Miscellaneous works in literature and philosophy," are the only reflection in this edition of the OEuvres of his activity within this institution. Equally excluded are, notably, the reports which Condorcet drafted from 1769 until the Revolution, the commentaries or summaries which he published in the "History" section of the Mémoires de l'Academie Royale des Sciences from his appointment as Secretary in the mid-1770s until the middle of the 1780s, and his "Prefaces" to the Mémoires de mathématiques et de physique présentés par divers Savans, drafted during the same period.

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The 1847-1849 edition did not redress these various exclusions of Condorcet's scientific work from the collection published in 1804.

2. The Collection of 1847-1849

As a letter from M. G. T. Villenave addressed to Eliza O'Connor at the end of summer 1845 indicates, the editors of 1847-1849, like those of 1804, first envisaged publishing at least a part of Condorcet's mathematical works. [START_REF]Villenave effectively alluded to a "mathematical part of the edition[END_REF] Despite this intent, the mathematical texts were again excluded. The simple statement of the rubrics of the edition of 1847-1849 is revealing: In the format of the 1847-1849 edition, these new texts fill almost 1,000 pages but only around 100 concern Condorcet's scientific works. Moreover, the scientific writings which this edition brought together -the Essai d'une histoire des correspondants de l'Académie, the Discours à l'Académie des sciences, and the Discours sur les sciences mathématiques and sur l'astronomie et le calcul des probabilités -were of a general, but not of a technical scope. In particular, they do not include any mathematical calculations.

Finally, another editorial choice illustrates this neglect of Condorcet's scientific thought.

Among the manuscripts of the Tableau historique des progrès de l'esprit known to the editors, 13 the only two that were not published were precisely those relatively complex pieces that were the closest to Condorcet's scientific interests: "Fragment 4," on a universal language, and "Note 9," devoted to technical methods of classification.

Thus, if the 1847-1849 edition is more complete than that of 1804, it still neglects Condorcet's scientific works. This exclusion is sizeable; even if the editors had included only printed texts and manuscripts existing as fair copies, the inclusion of these scientific works would have almost doubled the number of volumes in the 1804 and 1847-1849 editions; that is, they would have included approximately ten and twenty additional volumes, respectively. Why then did the editors choose to exclude so much of Condorcet's work?

WHY SUCH OMISSIONS?

One could imagine that the editors' inadequate knowledge of Condorcet's scientific works contributed to their exclusion from the 1804 and 1847-1849 collections, but this was not the case. The bulk of Condorcet's scientific works were available and known to the editors. Both after Condorcet's death and in the middle of the nineteenth century, however, these writings were neglected or judged negatively, including by friends and intellectual followers. The focus on Condorcet as an Enlightenment philosopher as well as a politician of the Revolution obscured his role as a scientist. This probably accounts for the editing of his works in the two editions of his OEuvres, even if more prosaic reasons were also involved, such as financial exigencies and the additional work that the publication of scientific works would have required. Regarding the 1847-1849 edition, my arguments draw from a perspective that P. Crépel developed. [START_REF]Ce qu'Arago a fait et n'a pas fait de l'oeuvre de Condorcet[END_REF]

1. Consciously excluded texts

Certainly the editors of 1804 and 1847-1849 did not know of the existence of dozens of manuscripts, beginning with those in the collections of the Bibliothèque Nationale de France. 15 In addition, certain academic works, notably those published in the "History" section of the Mémoires de l'Académie Royale des Sciences, were anonymous. Most of the BNF manuscripts are related to the Tableau historique des progrès de l'esprit humain; [START_REF]17 These texts are scattered through the volumes BIF MS 873 and MS 875[END_REF] they do not relate specifically to Condorcet's scientific thought and thus cannot help explain why his scientific works were set aside. In the case of the anonymous works, the 1804 editors had at their disposal several autograph manuscripts by Condorcet (which would later become the key holdings of the Bibliothèque de l'Institut de France) that authenticated his authorship of certain unsigned academic writings. 17 Etienne Cardot, Condorcet's private secretary from 1787, was probably aware of Condorcet's authorship of several of them; he could have told Sophie de Grouchy. The editors of 1847-1849 certainly knew of this anonymous corpus because they had access to most of the same autograph manuscripts and because Arago could not have been unaware of this body of work. As he was also Perpetual Secretary of the Academy of Sciences (1830-1853), Arago could not have been better placed to know that this position involved the presentation, sometimes without attribution, of scientific papers published by that institution. Moreover, in his biographical note on Condorcet, Arago declared that he knew of the correspondence between Lagrange and d'Alembert, [START_REF]Biographie de Jean-Antoine-Nicolas Caritat de Condorcet[END_REF] two letters of which [START_REF]Lettres de d'Alembert à Lagrange[END_REF] attest to Condorcet's authorship of the "History" section in the Mémoires de l'Académie Royal des Sciences as early as 1773 when he was named Fouchy's assistant.

Thus, no part of Condorcet's scientific work was omitted from the two collections of his OEuvres because the editors were unaware of it. Its absence resulted, rather, from a deliberate choice.

The scientist eclipsed by the man of the Enlightenment and of the Revolution

It is true that the 1804 editors had initially planned a section devoted to mathematics in their publication. But, as I have mentioned, this rubric was initially incomplete, and it was quickly eliminated. I have not found any explicit documentation about this decision.

Regarding Condorcet's works on pure mathematics, one can nevertheless suppose that Halma, in particular, was critical of the manuscript of the Traité du calcul intégral. [START_REF] Humboldt | [END_REF] Even during his lifetime, Condorcet was criticized, including by his friends, for the lack of clarity and precision in his work. 21 More generally, Condorcet's writings on pure mathematics were not particularly well thought of. It is also significant that Condorcet's name does not appear in the entry "Integral and Differential Calculus" or in the alphabetical classification in the index of volumes three and four (1802) of Montucla's Histoire des mathématiques, [START_REF] Passeron | Histoire des mathématiques[END_REF] dedicated to the seventeenth and eighteenth centuries. [START_REF]In a passage in his "Notice sur la vie et les ouvrages de Condorcet[END_REF] Although better known, Condorcet's work on "mixed" mathematics -what we would call today "applied" -did not rouse much enthusiasm in the aftermath of the Revolution. Leaving aside the hostile opinions of Condorcet's declared enemies, [START_REF] Such | Théorie du pouvoir politique et religieux dans la société civile[END_REF] or even those of supposedly more neutral authors, [START_REF] Mercier | Discours au Conseil des Cinq Cents[END_REF] it is truly remarkable that among his supporters Diannyère appears quite isolated in his praise for Condorcet's work; 26 the majority of authors either ignored or criticized more or less openly Condorcet's Social Mathematic. This was the case for Cabanis, one of the co-editors of the 1804 edition, who paid homage to his friend but was dubious about the use of mathematics in other fields of knowledge. 27 More generally, the Ideologues, who genuinely admired Condorcet, nonetheless neglected his Social Mathematic; among them, Degérando [START_REF] See | the philosophical section of M. Dacier, Rapport historique sur les progrès de l'histoire et de la littérature ancienne depuis 1789 et sur leur état actuel (présenté à l'Empereur le 20 février 1808[END_REF] and Destutt de Tracy [START_REF] Comte De Destutt De | Supplément à la première section des Elémens d'idéologie[END_REF] were later openly critical on essentially methodological grounds. Some authors close to the Ideologues condemned Condorcet's Social Mathematic more or less explicitly; J.B. Say, for instance, in his discussion of the difficulties involved in applying mathematics to political economy. [START_REF]Discours préliminaire[END_REF] These varying assessments, some from Condorcet's intimate friends, very likely contributed to the exclusion of his scientific works from the 1804 edition. The figure of the Enlightenment philosopher and politician defending the ideals of 1789, and victim of the Terror also cast a long shadow that obscured the scientist. One need only consider the reception of the Esquisse d'un tableau historique des progrès de l'esprit humain to appreciate the omnipresence of this interpretation. Composed by Condorcet shortly before his death, this work was extensively reviewed in the press; [START_REF]Tableau historique des progrès de l'esprit humain (1772-1794)[END_REF] the Convention ordered 3,000 copies, 32 and it was published at least sixteen times in various languages between 1795 and 1804. [START_REF][END_REF] A "philosophical manifesto of post-Thermidorian reconstruction," in the words of K. M. Baker, [START_REF] Baker | Condorcet. From Natural Philosophy to Social Mathematics[END_REF] this book seemed to be the legacy of an intellectual who died for the Revolution that he had served so well. His so-called OEuvres Complètes of 1804 can be seen in the same light. J. Sgard's analysis of the emergence of the idea of "complete works" is useful here. Noting a multiplication of such collections beginning in France in the last quarter of the eighteenth century, Sgard insists especially on the testamentary nature of "complete works": "The author dies with his pen in his hand . . . his work is entrusted to the nation. . . . The next step . . . is the consecration of the writer, giving him his due with funeral rites of inhumation, celebration, and immortalization." [START_REF] Sgard | Des collections aux oeuvres complètes, 1756-1798[END_REF] Condorcet's 1804 editors clearly shared this perspective: "The only consolation left to his family and friends is to have guided a complete edition of his works; it is the only compensation for his loss that they can offer his patrie and the republic of letters." [START_REF][END_REF] The truncation of the 1804 edition and its nearexclusive focus on Condorcet's works in the moral and political sciences were part of the rehabilitation of the republican philosopher in the aftermath of 9 Thermidor, 37 while his scientific works were overlooked.

The first decades of the nineteenth century did little to modify this image. With regard to pure mathematics, Condorcet's disciple, Lacroix, expressed a series of increasingly severe judgments against his master's analyses between 1810 and 1820. [START_REF] Gilain | Condorcet et le calcul intégral[END_REF] Lacroix ultimately declared the Traité du calcul intégral obsolete, a conclusion that led its exclusion at a time when the degree of an old work's utility to contemporary research could alone determine whether or not it would be published. Little by little, Condorcet's works were forgotten. Although more frequently commented upon, his research on applied mathematics enjoyed no greater esteem than before.

Only Duvillard, in his declarations as well as in his works, paid homage to Condorcet's Social Mathematic. [START_REF]Le Premier Actuaire de France: Duvillard[END_REF] Elsewhere, Condorcet's work was ignored or disparaged, as it had been in the aftermath of the Revolution. Paradoxically, Fayolle's 1805 edition of the Elémens du calcul des probabilités (1786-1787) further damaged Condorcet's reputation. It was hastily put together, full of omissions, and it artificially includes a very poor version of the Tableau général de la science qui a pour objet l'application du calcul aux sciences politiques et morales (1793). [START_REF]Condorcet, Arithmétique politique -Textes rares ou inédits (1767-1789[END_REF] Parisot's assessment, published in his Traité du calcul conjectural (1810), was unequivocal: "It is impossible to write more incoherently or obscurely." [START_REF]Traité du calcul conjectural ou l'art de raisonner sur les choses futures et inconnues[END_REF] Other mathematicians contributed little to restoring Condorcet's image. In the second edition of his Traité élémentaire du calcul des probabilités (1822), Lacroix underrated the originality of Condorcet's views by considering them as concepts borrowed from Hume and Laplace, while Laplace never quoted Condorcet and Cournot did so on only a few occasions. [START_REF] Bru | For further details about Lacroix, Laplace, and Cournot's view of Condorcet's work on probability[END_REF] Comte treated Condorcet with some deference, but he considered Condorcet's Social Mathematic as "entirely chimerical." [START_REF]Plan des travaux scientifiques nécessaires pour réorganiser la société[END_REF] We have seen that the editors of 1847-1849, like those of 1804, initially intended to maintain a place for Condorcet's scientific work in their collection. This plan's failure to materialize was possibly due in part to the bad reputation of those writings. Lacroix's final and most damning assessment, expressed in a letter to Eliza O'Connor herself, rejected the publication of the Traité du calcul intégral, which he judged obsolete. [START_REF] Lacroix | [END_REF] Isambert, one of the coeditors of the OEuvres de Condorcet, invoked Arago's authority as he harshly confirmed Lacroix's judgment: "his [Condorcet's] mathematical works can only be properly appreciated in the context of his era and in light of the judgment of his most competent peer, Arago, one of his successors as Perpetual Secretary of the Academy of Sciences." [START_REF]Nouvelle biographie générale[END_REF] One of the few nuances in the eulogy that Arago delivered to the Academy of Sciences in December 1841, was his assertion, with regard to Condorcet's work on comets, that calculations were not his strong point, [START_REF]Biographie de Jean-Antoine-Nicolas Caritat de Condorcet[END_REF] and Arago added more generally that Condorcet's "mathematical works . . . lack the elegant clarity that so clearly distinguishes the papers of Euler and Lagrange." 47 However, Arago, who was an advocate of applying mathematics to the social sciences, was relatively benevolent in his judgment of Condorcet's works. In another speech to the Academy in 1850, he placed his predecessor at the same rank as Laplace and Poisson. [START_REF]Biographie de Poisson[END_REF] Arago knew, however, of the torrent of criticism endured by Poisson following his presentation to the Academy in 1835 of his Recherches sur la probabilité des jugements en matière criminelle et en matière civile, an event which, indirectly, impeded any restoration of Condorcet's work to contemporary scientific favor.

Arago admitted as much in his 1841 biography of Condorcet when he indicated that "the struggle continues" over the use of mathematical probability "in the field of jurisprudence and the moral or political sciences." [START_REF]Biographie de Jean-Antoine-Nicolas Caritat de Condorcet[END_REF] Two elements may have motivated Arago's decision not to include Condorcet's Social Mathematic in the 1847-1849 OEuvres: the overly-polemical nature of Condorcet's work on this question and Arago's own risk of entering into conflict with many of his colleagues in the Academy. Finally, Arago probably excluded Condorcet's comptes rendus and other academic syntheses because he judged them minor, not particularly creative, or composed simply in response to professional obligations. This hypothesis seems to be confirmed by the fact that Arago chose not to include works of the same kind in his own OEuvres complètes (1854-1862), which he planned during his lifetime.

Clearly, Arago intended to promote the figure of the republican man of politics rather than the man of science. Although Arago declared in his biography that it was necessary to proceed with Condorcet's "rehabilitation" 50 as a man of science, as well as a moralist and a politician, only a fifth of the text concerns scientific issues, while the account of Condorcet's activity during the Revolution alone takes a good third. Arago had sat since 1830 on the left of the Chamber of Deputies and, as J. P. Schandeler has explained it, he found in Condorcet a legitimation of his own republican aspirations. [START_REF] Schandeler | Les interprétations de Condorcet -Symboles et concepts[END_REF] Arago delivered similar speeches on Bailly, Carnot, and Monge, and Libri explicitly reproached him for their emphasis on politics: "M Arago should make no mistake, the public does not come to the open meetings of the Academy to attend a political rally, but rather to learn the history of science, and to hear about sublime discoveries explained in ordinary language." [START_REF][END_REF] A lively polemic between Arago and Libri followed, which I will not review here. [START_REF]Ce qu'Arago a fait et n'a pas fait de l'oeuvre de Condorcet." 54 By comparison, among the forty-five editions of[END_REF] The key point is that Arago's biography, printed in the opening pages of the 1847-1849 edition of Condorcet's OEuvres, perfectly reflected the OEuvres's truncated contents.

3. Material Reasons

Earlier I mentioned the fact that the publication of Condorcet's scientific work -even restricted to the printed works and manuscripts in fair copies -would have almost doubled the number of volumes finally published in either 1804 or in 1847-1849. The additional costs would have been prohibitive, especially for the 1804 editors. Already luxurious because of its typography, which did not economize on space, that edition would have approached forty volumes, as exceptional a number at that time as it would be today. 54 In the years preceding the appearance of the 1804 edition, Sophie de Grouchy's correspondence with Barbier raised financial questions, although in a somewhat hazy fashion. [START_REF]where Napoleon's future private librarian refers to "costs of inheritance" (frais de legs), but his precise meaning is unclear[END_REF] A letter from Isambert to Eliza O'Connor in the summer of 1844 makes it clear that financial considerations also influenced the 1847-1849 edition: Isambert refers to a loan which Condorcet's daughter had contracted and to the savings realized during the correction of proofs because they were "printing from an alreadypublished edition," 56 that of 1804. If the 1847-1849 edition had been more voluminous and had included especially Condorcet's scientific manuscripts existing in fair copies, beginning with the Traité du calcul intégral, 57 the financial demands would have been even heavier.

The publication of Condorcet's scientific work would have required rereading and correcting many of his calculations. Shortly after his death, several people would certainly have been able to do it: his pupils, Duvillard and Lacroix, or certain mathematicians who were acquainted with the Traité du calcul intégral, 58 that is, Arbogast, Halma, and Lalande. But the corrections would have required much more work than for a literary text and would have been slow and laborious. By the middle of the 1840s, this undertaking would doubtless have proven still more arduous. Arago, notably, was competent for the task, but it is difficult to see how he would have had the time given his numerous social and political activities since the 1830s.

Conclusion

Studies devoted to Condorcet from the mid-nineteenth to the mid-twentieth century [START_REF] Charma | Condorcet -Sa vie et ses oeuvres[END_REF] remained focused on the image of an Enlightenment philosopher and a revolutionary, an image which continued to overshadow Condorcet the scientist. [START_REF] Gilain | Présentation" of "Mathématiques, Mécanique céleste, Métrologie," and Bru & Crépel[END_REF] Some modification of this perspective appeared with K. Pearson who examined Condorcet's theory of the "motive for believing" as it is presented in the Elémens du calcul des probabilités. [START_REF]The History of Statistics in the 17 th and 18 th centuries[END_REF] The rest of the story is better known: public choice theorists exhumed the Essai sur l'application de l'analyse, [START_REF] Notably | Social Choice and Individual Values[END_REF] while interest in Condorcet's work in social mathematics has also grown, with two monographs dedicated to it. [START_REF] Granger | La Mathématique sociale du marquis de Condorcet[END_REF] In the 1980s and 1990s finally, Condorcet was eventually recognized as the founder of mathematical expectancy theory and of the rule of statistical estimates, which he discovered before Laplace and independently from Bayes. [START_REF] Bru | Condorcet, Mathématique sociale et vérité[END_REF] Condorcet is also seen as the precursor of the general model of Markov chains [START_REF] Crépel | Condorcet, la théorie des probabilités et les calculs financiers[END_REF] and, in the field of pure mathematics, as the creator of the theory of integration in finite terms. [START_REF] Gilain | On this subject[END_REF] We may still ask, however, why this rehabilitation was so delayed. With regard to applied mathematics, the development of statistics and interest in the application of mathematics to social sciences since the Second World War have certainly been determining factors in the recognition of the value of Condorcet's research, often previously rejected because of a simplistic epistemological credo. With regard to pure mathematics, Condorcet's generalizing approach, which did not conform to the methodological canons of his time, contributed to his neglect. 67 In general, however, it seems that Condorcet's scientific works have suffered from simple cumulative neglect: because his scientific writing was little esteemed and was obscured by his work on moral and political sciences, it was set aside in his OEuvres of 1804 and 1847-1849. Because of its absence in these volumes, the scientific work has been little commented on and thus again neglected, falling into an editorial vicious circle. In the domain of applied mathematics, several publications, one of which returns to the original manuscripts, [START_REF] Bru | Arithmétique politique[END_REF] have appeared during the last twenty years coinciding with the bicentennial of the Revolution and the death of Condorcet. This interest has certainly contributed to a wider reading of Condorcet, but editorial fervor has not spread to the rest of his scientific work. At this time, the majority of Condorcet's academic works are only available in their original printed editions or as fair manuscript copies deposited in the archives of the Academy of Sciences. Almost none of the texts on pure mathematics have been published. [START_REF]the Moyens d'apprendre à compter sûrement et avec facilité[END_REF] The Traité du calcul intégral, to which Condorcet devoted several years of his life and which was, in size, the most important of his mathematical works, is today completely unavailable. On the eve of his death, Condorcet implicitly asked that this work be published. [START_REF]Je voudrais que le citoyen Arbogast fût chargé de mon manuscrit sur le calcul intégral, il est double & qu'il en fit usage utile en corrigeant les fautes[END_REF] We hope that his desire will soon be fulfilled. * I thank Carol Harrison for her translation.

1 Even though her name was not mentioned on the title page, Eliza O'Connor selected and edited most of the texts in that edition. On this point, see J. N. Rieucau, "Eliza O'Connor propose, François Arago dispose: l'écriture de la Biographie de Condorcet (1841, 1849) et l'édition de ses OEuvres (1847-1849)," in Arago et son temps (Paris: Estagel, forthcoming, 2005).

2 Remember Condorcet's tragic destiny. At the beginning of summer 1793, he went into hiding because of his criticism of the proposed Montagnard constitution. He was finally arrested 27 March 1794 and found dead in his cell one or two days later. The reasons for his death remain mysterious. Was it due to a poison that Cabanis might have given to him? Or was it the result of Condorcet's exhaustion? He was, after all, already an old man, and he had wandered in the countryside for several days. See E. & R. Badinter, Condorcet -Un intellectuel en politique (Paris: Fayard, 1988), 631-33.

5 

 5 from the Academy of Sciences c. Philosophical literature d. General and particular politics e. Political economy In the first of these categories, one finds the following texts: Du calcul intégral (1765)  Du problème des trois corps (1767)  Lettre à d'Alembert sur le système du monde et sur le calcul intégral (1768)  Some texts which appeared in the Mémoires de l'Académie Royale des Sciences (1772-1774)  Traité du calcul intégral (mid-1770s-early 1780)  Mémoire sur le canal de Picardie (1780)  Essai sur l'application de l'analyse à la probabilité des décisions rendues à la pluralité des voix (1785)  Moyens d'apprendre à compter sûrement et avec facilité (1794) Two other texts could have been placed in the "Mathematics" category. One, Sur l'évaluation des droits éventuels (1785), ended up in the category "Political economy." 6

  The reports which Condorcet drafted for the Academy of Sciences while Commissioner, from the beginning of the 1770s until the Revolutionary period  The majority of the texts published from the beginning of the 1770s until the middle of the 1780s in the Mémoires de l'Académie Royale des Sciences or in the collections of foreign academies (Berlin, Bologna, St. Petersburg, Turin, and Utrecht)  The "Prefaces" published between 1775 and 1784 in the Mémoires de mathématiques et de physique présentés par divers Savans  The articles from the Supplément à l'Encyclopédie (1776-1777) and the Encyclopédie Méthodique (1786-1787)  Four of the five parts of the Mémoire sur le calcul des probabilités (1784-1787)  The Elémens du calcul des probabilités (1786-1787) Even more of Condorcet's mathematical works were soon to be dropped: a letter from Sophie de Grouchy addressed to Barbier on 26 December 1798 (6 nivôse year VII) 8 refers to only three divisions, which constituted the final plan for 1804 OEuvres's twenty-one volumes:  Miscellaneous works on literature and philosophy (volumes I-X)  General and particular politics (volumes XI-XVIII)  Political economy (volumes XIX-XXI) The heading "Mathematics" has disappeared, while the second and third headings mentioned in the Catalogue des ouvrages de Condorcet have been combined under the heading "Miscellaneous works on literature and politics." As a consequence, all of the texts inventoried in the initial list for "Mathematics" have been excluded except for the Mémoire sur le canal de Picardie (1780). Directly associated with the work of Condorcet under the Turgot ministry (1774-1776), this text includes little mathematics and compares the costs of different canal construction projects. In this sense it belongs as much to political economy as it does to mathematics and finds quite naturally a place in volume XIX of the 1804 OEuvres (pp. 49-98) beside Concorcet's principal economic texts from the mid 1770s. The Tableau général de la science qui a pour objet l'application du calcul aux sciences politiques et morales (1793) is also present in the 1804 OEuvres, in volume XXI (pp. 235-86), a placement which might take into account the connections which Condorcet develops there between Social Mathematic and political economy. The "Third Part" (1785) of the Mémoire sur le calcul des probabilités (1784-1787) is, on the other hand, omitted.



  Correspondence and miscellaneous works (volume I)  Eulogies (volumes II-III)  Miscellaneous works in literature and philosophy (volumes IV-VI)  Political Economics and Politics (volumes VII-X)  Politics (volumes XI-XII)What are the differences between this edition and that of 1804? Four texts were cut out of the 1847-1849 edition because they were not by Condorcet or, in one case, were judged redundant.[START_REF]Eliza O'Connor explained that the "Avertissement" of the Essai sur les assemblées provinciales (1788), 13: i-iv was withdrawn because it was by Diannyère, not Condorcet. Similarly Eliza O'Connor attributed the "Avertissement[END_REF] Around forty other texts, as well as close to 200 letters, were added. These additions included works printed during Condorcet's life, previously unpublished writings that had appeared since 1804, and, finally, manuscripts that had never been published. Because of the editors' choice of subjects, this published material also slights Condorcet's scientific work. The following texts were added for the new edition: 12  Sur l'abolition des corvées (1775)  Essai d'une histoire des correspondants de l'Académie (1777)  A large part of the Correspondance, notably avec Turgot (1770-1779) and avec Voltaire (1770-1778)  Observations sur le vingt-neuvième livre de l'Esprit des lois (1780)  Fragments sur la liberté de la presse (c. 1781)  Dialogue entre Diogène et Aristippe (1783)  Two Discours à l'Académie française (6 June 1782 and 26 February 1784) and a Discours à l'Académie des sciences (12 November 1783)  Two addresses to the Lycée: Discours sur les sciences mathématiques (1786) and Discours sur l'astronomie et le calcul des probabilités (1787)  Around twenty political texts from the period 1790-1793, including Sur l'admission des femmes au droit de cité (1790), Sur la nécessité d'établir en France une constitution nouvelle (1793)  Writings from Condorcet's time in hiding: Fragment de justification (1793), Fragments 1, 2, and 3 of the Tableau historique des progrès de l'esprit humain (1793-1794), Conseils de Condorcet à sa fille (1794), Testament de Condorcet (1794)...  J. de Lespinasse, Portrait de Condorcet (1774)

Notice sur la vie et les ouvrages de Condorcet (2nd ed., 1799; Paris: Le livre d'histoire, 2000), 29-32, 36-37. See also Diannyère, Essais d'arithmétique politique (Paris: Goujon: year VIII (1799-1800)), where he prominently cites Condorcet.

On this point, see M. S. Staum, Cabanis -Enlightenment and Medical Philosophy in the French Revolution (Princeton: Princeton University Press, 1980), 104-5, 159, 210.


Cecile Fauvelot

Philippe Borsa
email: philippe.borsa@ird.fr

Patterns of genetic isolation in a widely distributed pelagic fish, the narrow-barred Spanish mackerel (Scomberomorus commerson)

Keywords:

Although migratory pelagic fishes generally exhibit little geographic differentiation across oceans, as expected from their life-history (broadcast spawning, pelagic larval life, swimming ability of adults) and the assumed homogeneity of the pelagic habitat, exceptions to the rule deserve scrutiny. One such exception is the narrow-barred Spanish mackerel (Scomberomorus commerson), where strong genetic heterogeneity at the regional scale has been previously reported. We investigated the genetic composition of S. commerson across the Indo-West Pacific range using control-region sequences (including previously published datasets), cytochrome-b gene partial sequences, and eight microsatellite loci, to further explore its phylogeographic structure. All haplotypes sampled from the Indo-Malay-Papua archipelago (IMPA) and the southwestern Pacific coalesced into a clade (Clade II) that was deeply separated (14.5% nucleotide divergence) from a clade grouping all haplotypes from the Persian Gulf and Oman Sea (Clade I). Such a high level of genetic divergence suggested the occurrence of two sister-species. Further phylogeographic partition was evident between the western IMPA and the regions sampled east and south of it, i.e. northern Australia, West Papua, and the Coral Sea. Strong allele-frequency differences were found between local populations in the southwestern Pacific, both at the mitochondrial locus (Φ ST =0.282-0.609) and at microsatellite loci (^θ=0.202-0.313). Clade II consisted of four deeply divergent subclades (9.0-11.8% nucleotide divergence for the control region; 0.3-2.5% divergence at the cytochrome b locus). Mitochondrial sub-clades within Clade II generally had narrow geographic distribution, demonstrating further genetic isolation. However, one particular haplogroup within Clade II was present throughout the central Indo-West Pacific; that haplogroup was found to be sister-group to an haplogroup restricted to West Papua and the Coral Sea, yielding evidence of recent secondary westward colonization. Such a complex structure is in sharp contrast with the generally weak phylogeographic patterns uncovered to date in other widely distributed, large pelagic fishes with pelagic eggs and larvae. We hypothesize that in S. commerson and possibly other Scomberomorus species, philopatric migration may play a role in maintaining the geographic isolation of populations by annihilating the potential consequences of passive dispersal.

INTRODUCTION

Knowledge of population genetic structure and identification of barriers to gene flow in marine organisms are important to understanding genetic-differentiation and speciation processes in the sea. Apart from obvious barriers such as continents, potential barriers to gene flow in the sea include oceanic fronts, temperature and salinity barriers, oligotrophy (as a mortality factor in e.g. drifting larvae), and predation [START_REF] Palumbi | Genetic divergence, reproductive isolation, and marine speciation[END_REF][START_REF] Graves | Molecular insights the population structures of cosmopolitan marine fishes[END_REF]. Genetic differentiation between populations may also arise from spawning asynchrony among populations, retention of eggs and larvae, and adult homing behaviour [START_REF] Taylor | Genetic Evidence for Local Retention of Pelagic Larvae in a Caribbean Reef Fish[END_REF]. An increasing number of marine taxa with high dispersal potential that were once thought to represent a single species distributed over several oceans (references in [START_REF] Briggs | Fishes of worldwide (circumtropical) distribution[END_REF][START_REF] Briggs | Marine Zoogeography[END_REF] are now recognized as multiple species, thanks to the development of molecular methods [START_REF] Knowlton | Sibling species in the sea[END_REF][START_REF] Knowlton | Molecular genetic analyses of species boundaries in the sea[END_REF]Colborn et al., 2001, and references therein).

Pelagic fishes generally exhibit little geographic differentiation across oceans [START_REF] Theisen | High connectivity on a global scale in the pelagic wahoo, Acanthacybrium solandri (tuna family Scombridae)[END_REF] and references therein), although a few exceptions have been reported [START_REF] Perrin | Mitochondrial DNA analysis of the geographic structure of Indian scad mackerel, Decapterus russelli (Carangidae) in the Indo-Malay archipelago[END_REF][START_REF] Rohfritsch | Genetic structure of Indian scad mackerel Decapterus russelli: Pleistocene vicariance and secondary contact in the Central Indo-West Pacific Seas[END_REF][START_REF] Lu | Population genetic structure of the swordfish, Xiphias gladius, in the Indian Ocean and West Pacific inferred from the complete DNA sequence of the mitochondrial control region[END_REF][START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF]. One such case is the narrow-barred Spanish mackerel (Scomberomorus commerson Lacepède 1800) where evidence of strong population structure has been reported [START_REF] Buckworth | The stock structure of northern and western Australian Spanish mackerel[END_REF] and where preliminary phylogeographic investigations have suggested a possible phylogeographic gap coinciding with Wallace"s Line [START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF]. S. commerson is an inshore pelagic species capable of long migrations [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF]. At the basis of important commercial, recreational and artisanal fisheries, the annual world catch of S. commerson has steadily increased from less than 70,000 tons in the seventies to over 220,000 tons in 2008 (FAO -Fisheries and Aquaculture Information and Statistics Service; http://www.fao.org/fishery/species/3280/en). Spanish mackerels (genus Scomberomorus) constitute the most speciose group in the family Scombridae [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF]. Eighteen species are currently recognized in that genus, the majority of which have a geographic distribution limited to a single ocean basin [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF]. The distribution of S. commerson spans more than 160° longitude and 80° latitude in the Indo-West Pacific (Fig. 1) whereas all other Scomberomorus species are distributed within 80° longitude and 80° latitude, and often much less [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF]. Therefore, the wide geographic distribution of S. commerson contrasts with that of all other species in the genus Scomberomorus. Since species in the genus Scomberomorus share a similar morphology, similar ecological traits, and apparently similar abilities for migration, this contrast in their respective geographic distributions is remarkable. A possible explanation might be that S. commerson actually consists of two or more cryptic species, each with narrower geographic distribution. Significant morphometric differences have been noted between populations across the Indo-Pacific [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF].

Although S. commerson is usually regarded as a highly migratory fish [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF], and references therein), significant allozyme-genetic differences have also been reported between populations at the regional scale. Three main stocks, centered on northern Australia, Papua New Guinea and Fiji [START_REF] Shaklee | Analysis of fish stock structure and mixed-stock fisheries by the electrophoretic characterization of allelic isozymes[END_REF]) and of a fourth stock off Queensland (J.B. Shaklee in [START_REF] Buckworth | The stock structure of northern and western Australian Spanish mackerel[END_REF] have been delineated. Based on sequence polymorphism of the mitochondrial control region, [START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF] hypothesized an east-west phylogeographic division within the IMPA. Conversely, no genetic differences were detected at the same locus, among samples from the Persian Gulf and the Oman Sea [START_REF] Hoolihan | Mitochondrial DNA analyses of narrow-barred Spanish mackerel (Scomberomorus commerson) suggest a single genetic stock in the ROPME sea area (Arabian Gulf, Gulf of Oman, and Arabian Sea)[END_REF]. So far, no population genetic study of S. commerson has covered a significant part of its distribution and, to our knowledge, no attempt has been made to combine the results from studies that shared the same genetic markers. The objective of the present paper is to investigate the phylogeography of S. commerson at the scale of the Indo-West Pacific to: (1) test the east-west phylogeographical hypothesis of [START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF]; and (2) examine the possible occurrence of additional distinct populations of S. commerson, from the Persian Gulf to New Caledonia, that is, across over 120° (~71%) of its longitudinal range. For this, we analyzed samples from the Indo-Malay-Papua archipelago (Java Sea, Bali, West Papua) and from New Caledonia using mitochondrial and nuclear genetic markers, and merged the resulting dataset with previously published mitochondrial sequence datasets from the Persian Gulf and Oman Sea [START_REF] Hoolihan | Mitochondrial DNA analyses of narrow-barred Spanish mackerel (Scomberomorus commerson) suggest a single genetic stock in the ROPME sea area (Arabian Gulf, Gulf of Oman, and Arabian Sea)[END_REF]) and from the central Indo-West Pacific [START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF].

MATERIALS AND METHODS

SAMPLING

Fin clips were sampled from Scomberomorus commerson obtained from fishermen or from retailers at fish landing places in Indonesia (Java Sea, Bali), West Papua and New Caledonia (Fig. 1) in 2007-2009. The "Java Sea" sample (JAVA; N=4) was collected at the Muara Angke fish market, Jakarta; the "Bali" sample (BALI; N= 6), consisting of fish from the Bali Strait, was collected at the Jimbaran fish market, southern Bali; the "West Papua" sample (WPAP) consisted of 10 individuals fished in Raja Ampat waters and sold at the Sorong fish market, northwestern West Papua; the "New Caledonia" sample (NCAL) consisted of a total of N=194 individuals fished in the Belep islands in the northern lagoon of New Caledonia, and off Nepoui (northwestern lagoon of New Caledonia), Nouméa (southwestern lagoon) and Canala (eastern coast), all obtained from local fishermen. Fin clips were preserved in 95% ethanol and shipped to Perpignan, France, for analysis.

MOLECULAR ANALYSIS

Genomic DNA was isolated from fin clip using the Gentra Puregene tissue Kit (Qiagen, Germantown, USA) following the manufacturer"s protocol. Amplification of the highly variable 5" end of the mitochondrial control region (380-383 bp) was done by polymerase-chain reaction (PCR) using the universal CR-A (TTC CAC CTC TAA CTC CCA AAG CTA G) and CR-E (CCT GAA GTA GGA ACC AGA TG) primers [START_REF] Lee | Structure and evolution of teleost mitochondrial control region[END_REF]. Each PCR was done in 25 L reaction mixture containing 1X PCR buffer (Promega Corporation, Madison, USA), 0.5 mM MgCl 2 , 0.08 mM of each dNTP, 0.2 M of each primer, 0.5 U of GoTaq TM DNA Polymerase (Promega Corporation) and about 30 ng genomic DNA. The amplification of the control-region fragment was achieved by 35 cycles of denaturation (30 s at 94°C), annealing (30 s at 51°C), and extension (1 min at 72°C).

A random subsample of individuals from the Java Sea (N=4), Bali (N=6), West Papua (N=7) and a subsample of New Caledonia (N=74; including individuals of Haplogroup ii and randomly chosen individuals representing each of the three sub-clades IIA, IIb and IId; see Results) were PCR-amplified for an additional 281-bp fragment of the cytochrome b gene, using primers CB1-L (5' CCATCCAACATCTCAGCATGATGAAA 3') and modified CB2-H (5' CCCTCAGAATGATATTGGTCCTCA 3') [START_REF] Palumbi | The simple fool"s guide to PCR, version 2.0[END_REF]. The reaction mixture and PCR parameters were the same as those used for the control region. PCR products were sent to GATC Biotech (Konstanz, Germany) for nucleotide sequencing: after purification, the PCR-amplified DNA fragments were sequenced using the CR-A primer (for the control-region fragment) or the CB1-L primer (for the cytochrome b gene fragment) and the sequence reaction products were run on an ABI 3730XL automated sequencer (Applied Biosystems, Foster City, USA). All nucleotide sequences were deposited in GenBank (http://www.ncbi.nlm.nih.gov/) under accession numbers HQ403255 to HQ403349 (cytochrome b) and HQ403350 to HQ403561 (control region).

We further amplified alleles at eight microsatellite loci specifically developed for S. commerson from the Persian Gulf and the Oman Sea [START_REF] Van Herwerden | Development and application of microsatellite markers for Scomberomorus commerson (Perciformes; Teleostei) to a population genetic study of Arabian Peninsula stocks[END_REF] in the individuals from Bali, Java, West Papua, and in a sub-sample of 66 randomly selected individuals from New Caledonia. Forward primers were labeled with ABI fluorescent dyes as follows: C83Sc / 6-FAM, L42Sc / 6-FAM, H96Sc / VIC, D61Sc / VIC, J43Sc / PET, E27Sc / PET, F6Sc / NED, J10Sc / NED. All eight microsatellite marker DNAs were amplified in a single 10 L multiplex PCR reaction using the Type-it Microsatellite PCR Kit (Qiagen) according to the manufacturer"s protocol, and using an annealing temperature of 57°C. Amplified fragments were sent to GATC Biotech where they were separated on an ABI 3730XL sequencer, with a GeneScan® LIZ-500 internal size standard (Applied Biosystems). The GENEMAPPER software (Applied Biosystems) was used to genotype all individuals screened. Finally, GMCONVERT [START_REF] Faircloth | GMCONVERT: file conversion for GENEMAPPER output files[END_REF] was used to convert the GENEMAPPER table of genotypes into a GENEPOP [START_REF] Raymond | GENEPOP (version 1.2): a population genetics software for exact test and ecumenicism[END_REF] input file.

DATA ANALYSIS Nucleotide sequences were aligned visually under BIOEDIT [START_REF] Hall | BIOEDIT: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT[END_REF]. A Median-joining parsimony analysis was performed using NETWORK [START_REF] Bandelt | Median-joining networks for inferring intraspecific phylogenies[END_REF] on the nucleotide-sequence matrix of 454 individual control region haplotypes aligned over 310 bp, which comprised the 216 new sequences produced in this study, aligned with sequences available from the literature. The latter included the Persian Gulf / Oman Sea dataset of [START_REF] Hoolihan | Mitochondrial DNA analyses of narrow-barred Spanish mackerel (Scomberomorus commerson) suggest a single genetic stock in the ROPME sea area (Arabian Gulf, Gulf of Oman, and Arabian Sea)[END_REF] (193 sequences; GenBank AM234345-AM234537), the Indo-Malay dataset of [START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF] (47 sequences re-constructed from their Table 1 and from the single GenBank sequence deposited by the authors, GenBank EU526382, identified by us as being that of haplotype ScPHI01), and two sequences from J.R. Ovenden and R. Street (in Buckworth et al., 2007), ScEC10 from eastern Australia (AY205242) and ScNA12 from northern Australia (AY205243) which were added to Sulaiman & Ovenden"s (2009) samples "12" and "11", respectively. The root of the network was determined using an outgroup (S. niphonius: GenBank nos. FJ69105-FJ659112) by maximum parsimony analysis in MEGA version 5 [START_REF] Tamura | MEGA 5: Molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods[END_REF]. The choice of S. niphonius as outgroup was motivated by its close systematic proximity with S. commerson [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF] and by the availability of control-region sequences for this species in GenBank.

To assess rates of genetic divergence between groups of lineages, nucleotide substitution models that best fit mitochondrial control-region and cytochrome b sequence data were tested using a model selection analysis based on the maximum-likelihood method implemented in MEGA. Evolutionary models of nucleotide substitution were different relative to mitochondrial DNA fragments. The tests revealed that the model that best fit the mitochondrial control-region data was HKY85 [START_REF] Hasegawa | Dating the human-ape splitting by a molecular clock of mitochondrial DNA[END_REF] with gamma correction and a heterogeneous proportion of invariable sites. However, because this model was not proposed in MEGA and ARLEQUIN version 3.11 [START_REF] Excoffier | ARLEQUIN ver. 3.0: An integrated software package for population genetics data analysis[END_REF] for further analysis, we chose to use the second best fit, which was TN93 [START_REF] Tamura | Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees[END_REF] with gamma correction (G = 0.76) and a heterogeneous proportion of invariable sites (I = 0.42). The model that best fit the cytochrome b data was Kimura 2-paramaters [START_REF] Kimura | A simple method for estimating evolutionary rate of base substitutions through comparative studies of nucleotide sequences[END_REF]. Mean net nucleotide divergences, defined as d xy -0.5 (d x +d y ), that subtracts the average 'within group' divergence from the observed 'between group' estimate [START_REF] Nei | Mathematical model for studying genetic variation in of restriction endonucleases[END_REF] were then estimated using the appropriate nucleotide substitution model for each sequence set in MEGA. Finally, the Tamura 3-parameter model [START_REF] Tamura | Estimation of the number of nucleotide substitutions when there are strong transitiontransversion and G+C-content biases[END_REF] with a heterogeneous proportion of invariable sites (I = 0.84) was found to be the best fit for the merged (control region + cytochrome b gene) sequence dataset, i.e. composite haplotypes obtained by merging partial sequences of the cytochrome b gene and of the control region for samples from Java Sea, Bali and West Papua, and a subsample (N=74) from New Caledonia. The homologous haplotype in S. niphonius was obtained by merging the homologous sequences from GeneBank (cytochrome b: DQ497887; control region: FJ659108) and used as outgroup.

Genetic diversity within regions was estimated as haplotype diversity (Hd: [START_REF] Nei | Molecular evolutionary genetics[END_REF], nucleotide diversity (π: [START_REF] Nei | Molecular evolutionary genetics[END_REF], and the average number of nucleotide differences between two sequences (k, [START_REF] Tajima | Evolutionary relationship of DNA sequences in finite populations[END_REF]) using DNASP version 5.10 (Librado & Rozas, 2009). Tajima"s D tests [START_REF] Tajima | Statistical method for testing the neutral mutation hypothesis by DNA polymorphism[END_REF] were conducted in DNASP by pooling samples within regions. Regions were defined on a geographical basis as follows: Persian Gulf + Oman Sea (samples AUH, BAH, DIB, IRN, KUW, OMN and RAK of Fig. 1); East China Sea (1); South China Sea + Malacca Strait (2-8); Java Sea + Bali (JAVA, BALI); Timor Sea + Arafura Sea (9-11); West Papua (WPAP); Coral Sea (12, NCAL). Observed haplotype diversities were compared to the empirical distribution of this index generated using coalescent simulations (H test; [START_REF] Depaulis | Neutrality tests based on the distribution of haplotypes under an infinitesite model[END_REF], performed in DNASP. The computer simulations were based on the coalescent process for a neutral infinite-sites model under the assumption of a large constant population size [START_REF] Hudson | Gene genealogies and the coalescent process[END_REF]. DNASP generates the empirical distribution of Hd, obtained from 10 000 simulations under the neutral coalescent process and given the number of segregating sites observed in each sampled population (the model therefore considers that the number of segregating sites is fixed and that mutations are uniformly distributed, at random, along lineages). DNASP thus estimates the probability of obtaining lower or higher values of Hd, computed from the simulation (Hd sim ), than the one observed in each sample (Hd obs ). These simulations were conducted within regions, pooling samples as described above.

Nucleotide-sequence divergences between populations were estimated using -statistics and the [START_REF] Tamura | Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees[END_REF] nucleotide substitution model with gamma correction (G=0.76) under ARLEQUIN version 3.11 [START_REF] Excoffier | ARLEQUIN ver. 3.0: An integrated software package for population genetics data analysis[END_REF]. P-values were obtained using a non-parametric permutation procedure with 10,000 permutations on the original matrix of sequences. A hierarchical analysis of molecular variance (AMOVA: Excoffier, Smouse & Quattro, 1992) was performed using ARLEQUIN to examine the partitioning of the total variance among regional groups of samples.

Significance of -statistics and associated variance components was tested by 10,000 random permutations.

For the microsatellite dataset, genetic diversity within samples was estimated at the eight loci as the observed (H O ) and expected (H E ) heterozygosities in GENETIX version 4.05 [START_REF] Belkhir | GENETIX 4.05, Logiciel sous WINDOWS TM pour la Génétique des Populations. Laboratoire Génome, Populations, Interactions[END_REF]. Deviations from Hardy-Weinberg (HW) equilibrium were estimated within and over all samples using [START_REF] Weir | Estimating F-statistics for the analysis of population structure[END_REF] inbreeding coefficient and departures from HW expectations were assessed using the permutation procedure in GENETIX. Null alleles were detected with MICRO-CHECKER [START_REF] Van Oosterhout | MICRO-CHECKER: software for identifying and correcting genotyping errors in microsatellite data[END_REF]. Pairwise genetic divergences among samples were estimated using multilocus Weir & Cockerham"s (1984) estimator of F ST (^θ), and their significance tested with 10,000 permutations of individuals among samples in GENETIX. Correspondence analysis [START_REF] Benzécri | L'Analyse des Données[END_REF] was performed on the matrix of individual multilocus genotypes using GENETIX. The sequential Bonferroni correction [START_REF] Rice | Analyzing tables of statistical tests[END_REF] was applied for each test.

RESULTS

The length of the amplified mitochondrial DNA control-region fragment in samples JAVA, BALI, WPAP and NCAL (total N=212) varied between 380 and 383 nucleotides. The nucleotide sequences were unambiguously aligned over 385 bp. Those 212 sequences were then aligned with 242 control-region sequences available from the literature (see Material and Methods) producing a total dataset of 454 sequences aligned over 310 bp. We observed 119 variable nucleotide sites: 148 substitutions were counted, 19 of which were singletons. The G+C content was close to 30%. A total of 221 haplotypes were scored; total haplotype diversity was 0.959, nucleotide diversity was 0.088 and the average number of nucleotide differences between two haplotypes was 24.74.

The Median-joining parsimony network connecting all 221 control-region haplotypes is presented in Figure 2. Maximum parsimony analysis conducted using Scomberomorus niphonius sequences as outgroup placed the root of the network between a group comprising all haplotypes sampled in the Persian Gulf and the Oman Sea (hereafter designated as Clade I) and the rest of the samples (south-east Asia and Oceania: Clade II). Mean net divergence between Clade I and Clade II was 14.5 ± 3.0%. Clade II comprised four main sub-clades (hereafter named IIa, IIb, IIc and IId) radiating from a central, poorly defined group of haplotypes (here coined "Haplogroup ii" and delineated by dots on Figure 2 Expanding the length of the mitochondrial fragment on a subsample of individuals allowed us to resolve the phylogenetic placement of haplotypes included in the above, undefined Haplogroup ii (Fig. 3). Clade II haplotypes thus clustered into four distinct sub-clades, namely IIa, (IIb+ii) (where Haplogroup ii appeared as a sister-branch to IIb), IIc and IId (Fig. 3). Mean net divergence between sub-clades, estimated from control-region nucleotide sequences, varied from 9.0 ± 2.3% (between Sub-clades IIa and IId), to 11.8 ± 2.8% (between Sub-clades IIa and IIc). Mean net divergence between subclades estimated from partial cytochrome b gene sequences alone ranged from 0.3 ± 0.3% (between sub-clades IIa and IId) to 2.5 ± 0.9% [between sub-clades (IIb+ii) and IIc].

Genetic divergence estimates among sampling locations, expressed as pairwise  ST, ranged from 0 to 0.965 (Table 1). Although, some pairwise  ST estimates should be taken with caution because of low sample sizes, e.g. between sample 2 from Thailand and sample 9 from Kupang, West Timor ( ST =0.965), generally high levels of genetic differentiation were observed between samples (Table 1). The Persian Gulf / Oman Sea samples were very distinct from all other samples ( ST =0.735-0.800). Within the latter group, the West Papuan and New Caledonian samples were themselves much differentiated from all the other samples ( ST =0.251-0.851). Pairwise  ST estimates were also generally high within the Coral Triangle, though not significant presumably because of low sample sizes. The AMOVA indicated that a large and highly significant proportion (75%) of the total mitochondrial variance resided among regions (Table 2). Excluding the East China Sea sample (because of its low size) and the Indian Ocean samples, the proportion of the total mitochondrial variance attributed among five geographically defined groups of samples across the Indo-Malay-Papuan archipelago and southwestern Pacific Ocean [(South China Sea + Malacca Strait); (Java Sea + Bali); (Timor Sea + Arafura Sea); West Papua; Coral Sea) was high (46%, P<<0.001). A small but significant part of the total variance (1.23%) was observed within groups, while 26% of the total variance was attributed among individuals within samples (Table 2). Within geographically defined regions, estimated haplotype diversity ranged from 0.82 in the Coral Sea to 1 in Java Sea/ Bali, and nucleotide diversity ranged from 0.023 in West Papua to 0.017 in the East China Sea (Table 3). The mean number of nucleotide differences between two sequences ranged from 6.72 in West Papua to 15.26 in South China Sea / Malacca Strait (Table 3). Most samples (here grouped by region) showed higher haplotype diversity than expected from the neutral coalescent theory on the basis of the number of observed segregating sites [Depaulis & Veuille"s (1998) haplotype diversity test: Table 3], while none of them deviated from neutrality according to Tajima"s D test (Table 3). Low sample sizes for some samples, or non-equilibrium conditions may explain this discrepancy.

Genetic diversity estimated from the analysis of the eight microsatellite loci is presented in Table 4. Average observed heterozygosity across all eight loci ranged from 0.521 in Bali to 0.571 in New Caledonia. The distribution of genotype frequencies at a locus did not differ significantly from Hardy-Weinberg expectations (standard Bonferroni correction applied) except sample NCAL at locus D61Sc (Weir & Cockerham"s ^f = 0.639; P < 0.001). Null alleles were detected at loci D61Sc in New Caledonia, L42Sc in Bali and E27Sc in West Papua. The graphical illustration of the correspondence analysis conducted on microsatellite multilocus genotypes revealed geographic partition: individuals from West Papua and New Caledonia formed two completely disjunct clusters, themselves clearly separated from an ensemble including all individuals sampled in Bali and in the Java Sea (Figure 4). So, there was no evidence of interchange of individuals among sub-regions in the southwestern tropical Pacific. Estimates of Weir & Cockerham"s parameter of genetic differentiation (θ) were ^θ =0.233 between Java/Bali and West Papua, ^θ =0.313 between Java/Bali and New Caledonia, and ^θ =0.202 between West Papua and New Caledonia.

DISCUSSION

Phylogeographic breaks between Indian and western Pacific populations have been reported for several widely distributed Indo-Pacific species [START_REF] Benzie | Major genetic differences between crown-of-thorns starfish (Acanthaster planci) populations in the Indian and Pacific Oceans[END_REF][START_REF] Barber | Comparative phylogeography of three codistributed stomatopods: origins and timing of regional lineage diversification in the coral triangle[END_REF][START_REF] Kochzius | Strong genetic population structure in the boring giant clam, Tridacna crocea, across the Indo-Malay Archipelago: implications related to evolutionary processes and connectivity[END_REF][START_REF] Carpenter | Comparative phylogeography of the Coral Triangle and implications for marine management[END_REF]. Barriers to gene flow have been located within the Indo-Malay-Papuan archipelago (IMPA), although the precise location varies extensively across species [START_REF] Carpenter | Comparative phylogeography of the Coral Triangle and implications for marine management[END_REF]. In fishes, phylogeographic studies spanning the IMPA have shown evidence of sub-division between Indian Ocean vs. Pacific Ocean populations in a number of benthic shore species (e.g. [START_REF] Lourie | Dispersal, habitat differences, and comparative phylogeography of Southeast Asian seahorses (Syngnathidae: Hippocampus)[END_REF][START_REF] Drew | Sequential cladogenesis of the reef fish Pomacentrus moluccensis (Pomacentridae) supports the peripheral origin of marine biodiversity in the Indo-Australian archipelago[END_REF][START_REF] Carpenter | Comparative phylogeography of the Coral Triangle and implications for marine management[END_REF] but not in others (e.g. [START_REF] Stepien | Genetic and morphological divergence of a circumtropical complex of goatfishes: Mulloidichthys vanicolensis, M. dentatus, and M. martinicus[END_REF][START_REF] Klanten | Extreme genetic diversity and temporal rather than spatial partitioning in a widely distributed coral reef fish[END_REF][START_REF] Horne | High population connectivity across the Indo-Pacific: congruent lack of phylogeographic structure in three reef fish congeners[END_REF][START_REF] Gaither | Genetic evaluation of marine biogeographic barriers: perspectives from two widespread Indo-Pacific snappers (Lutjanus kasmira and Lutjanus fulvus)[END_REF][START_REF] Winters | Phylogeography of the Indo-Pacific parrotfish Scarus psittacus: isolation generates distinctive peripheral populations in two oceans[END_REF]. Since, unlike most benthic fishes, pelagic fishes add extreme adult mobility to passive dispersal at the larval and juvenile stages, it is appropriate to consider them separately: genetic studies of large pelagic fishes such as tunas, wahoo and swordfish have not yielded conclusive evidence of geographic partition across the Indo-Pacific (Alvarado- [START_REF] Bremer | Genetic evidence for inter-oceanic subdivision of bigeye tuna (Thunnus obesus) populations[END_REF][START_REF] Chow | Nuclear and mitochondrial DNA analyses reveal four genetically separated breeding units of the swordfish[END_REF][START_REF] Durand | Nuclear and mitochondrial DNA markers indicate unidirectional gene flow of Indo-Pacific to Atlantic bigeye tuna (Thunnus obesus) populations, and their admixture off southern Africa[END_REF][START_REF] Ely | Consequences of the historical demography on the global population structure of two highly migratory cosmopolitan marine fishes: the yellowfin tuna (Thunnus albacares) and the skipjack tuna (Katsuwonus pelamis)[END_REF]Gonzales, Beerli & Zardoya, 2008;[START_REF] Theisen | High connectivity on a global scale in the pelagic wahoo, Acanthacybrium solandri (tuna family Scombridae)[END_REF][START_REF] Jaimes | Global phylogeography of the dolphinfish (Coryphaena hippurus): the influence of large effective population size and recent dispersal on the divergence of a marine pelagic cosmopolitan species[END_REF], whereas contrasted patterns have been found in small inshore pelagic fishes like scad mackerels (genus Decapterus; Carangidae), from broadscale geographic homogeneity (D. macrosoma: [START_REF] Borsa | Genetic structure of round scad mackerel Decapterus macrosoma (Carangidae) in the Indo-Malay archipelago[END_REF] to sharp population partition (D. russelli: [START_REF] Rohfritsch | Genetic structure of Indian scad mackerel Decapterus russelli: Pleistocene vicariance and secondary contact in the Central Indo-West Pacific Seas[END_REF] within the Indo-Malay-Papua archipelago. A summary of genetic-differentiation index estimates in broadcast-spawning Indo-West Pacific bony fishes of various habitats is presented in Table 5. The level of geographic differentiation in S. commerson is much higher than all other pelagic species studied so far, with the possible exception of Decapterus russelli, and it is matched only by rare examples of benthic shore species (Table 5).

DISTANT MITOCHONDRIAL CLADES I AND II INDICATE CRYPTIC SPECIES

Here, deep phylogeographic partition was observed between the Scomberomorus commerson population sampled in the Persian Gulf and the Oman Sea, and those populations sampled in the Indo-Malay-Papua archipelago and in the western Pacific. The 14.5% control-region sequence divergence observed between Clade I and Clade II and its correlation with geography indicate a clear separation between a northwestern Indian Ocean (Persian Gulf / Oman Sea) form of narrow-barred Spanish mackerel, and a western Pacific Ocean form. This level of nucleotide divergence is higher than inter-specific sequence divergences estimated using the same genetic marker between blue and chub mackerels (genus Scomber; Scombridae) (1.7-9.6%: Catanese, Manchado & Infante, 2010), among scad mackerels (genus Decapterus, Carangidae) (2.7-11.7%: [START_REF] Arnaud | Mitochondrial DNA analysis of the genetic relationships among populations of scad mackerel (Decapterus macarellus, D. macrosoma and D. russelli) in South-East Asia[END_REF] and among horse mackerels (genus Trachurus, Carangidae) (1.0-9.6%: [START_REF] Cárdenas | Origin, diversification, and historical biogeography of the genus Trachurus (Perciformes: Carangidae)[END_REF]. It is also higher than inter-specific genetic divergences for benthic species, e.g. damselfishes (10. 1-12.8%;[START_REF] Timm | Contrasting patterns in species boundaries and evolution of anemonefishes (Amphiprioninae, Pomacentridae) in the centre of marine biodiversity[END_REF][START_REF] Bernardi | Species boundaries, populations, and colour morphs in the coral reef three-spot damselfish (Dascyllus trimaculatus) speciescomplex[END_REF] and more generally higher than genetic divergence at the inter-specific level in fishes [START_REF] Mccune | The relative rate of sympatric and allopatric speciation in fishes: tests using DNA sequence divergence between sister species and among clades[END_REF][START_REF] Lessios | The great American schism: divergence of marine organisms after the rise of the Central American Isthmus[END_REF].

The present results suggest that the S. commerson form sampled in the Indo-Malay-Papua archipelago and in the western Pacific Ocean is a species different from that sampled in the Persian Gulf and the Oman Sea. The relatively large differences in morphology and in meristic characters reported between S. commerson sampled in the Indian Ocean and those from the "East Indies" [START_REF] Collette | Morphology, systematics, and biology of the Spanish mackerels (Scombridae)[END_REF]their table 15), are consistent with this hypothesis. Therefore, the large distribution of S. commerson, an exception among species of that genus, might well be an artefact that results from the taxonomic confusion of cryptic species.

PHYLOGEOGRAPHIC BREAK WITHIN THE INDO-MALAY-PAPUA ARCHIPELAGO AND FURTHER

PARTITIONING AT THE REGIONAL SCALE Further phylogeographic partition was found within the western Pacific Ocean form of S. commerson. Clade II haplotypes, which characterize that form, clustered into four distinct sub-clades separated by 0.3-2.5% net nucleotide divergence at the cytochrome b locus and 9.0-11.8% for control region. Sub-clade IIc was exclusively found, and dominant, in the western half of the Indo-Malay-Papua archipelago (i.e. west to a line running from Timor to West Papua), whereas Sub-clades IIa, and IId were exclusively found east and south of a line running from Bali to the Philippines. The root of the cytochrome b tree presented in Figure 3 was between Sub-clade IIc and the rest, suggesting that the genetic differences between S. commerson populations of the western half of the Indo-Malay-Papua archipelago and those east and south of it result from vicariance. Sub-clade IIa was sampled in New Caledonia only, which suggests that it may be endemic to New Caledonia, or at least geographically restricted to the southeastern extremity of the range of S. commerson. The remaining sub-clade, (IIb+ii), itself consisted of two sister-branches (hereafter "Branch IIb" and "Haplogroup ii") with different geographic distributions. Branch IIb was dominant in New Caledonia and it was also found in West Papua and in northern Australia. In contrast, Haplogroup ii haplotypes were found throughout the Indo-Malay-Papua archipelago and the western Pacific Ocean.

The distinctness of S. commerson populations from New Caledonia and West Papua was further demonstrated by the strong pairwise divergence estimate over eight microsatellite loci. We are aware of a few genetic studies in other species of the genus Scomberomorus that can be used as a basis of comparison with the present results in S. commerson at the regional scale (Table 6). Observed F ST -estimates between populations at the regional scale in S. commerson were considerably higher (one order of magnitude for nuclear loci) than those estimated for any other Scomberomorus species. This indicated that very little, if any gene flow connects S. commerson populations in the tropical southwestern Pacific Ocean. Interestingly, F ST estimates at the same microsatellite loci within S. commerson sampled in the Persian Gulf and in the Oman Sea were relatively low (range 0-0.078), though sampled over geographic distances similar to that between Bali and West Papua [START_REF] Van Herwerden | Development and application of microsatellite markers for Scomberomorus commerson (Perciformes; Teleostei) to a population genetic study of Arabian Peninsula stocks[END_REF].

The clover-like structure of Clade II and its relationship to the geographic distribution of haplotypes imply that western Pacific S. commerson populations have been isolated from each other for a period of time long enough to achieve reciprocal monophyly. The geographic distribution of haplotypes correlates with their phylogenetic structure, with the exception of Haplogroup ii haplotypes. A possible explanation to that intriguing pattern is that a proto-Haplogroup ii population initially restricted to the eastern part of the distribution of S. commerson secondarily diffused westward to colonize the entire Indo-Malay-Papua archipelago, where it entered into secondary contact with populations harbouring Sub-clade IIc haplotypes. The question that follows is whether those two branches are reproductively isolated from each other. TESTING FOR REPRODUCTIVE ISOLATION It is possible to test for reproductive isolation between groups of individuals that harbour different mitochondrial types by using nuclear markers, when those groups also happen to occur in sympatry. Microsatellite genotypes were available for three S. commerson samples (BALI, WPAP and NCAL) with a heterogeneous mitochondrial composition. Heterozygote deficiency was effectively observed at one locus in the NCAL sample, but this was ascribed to null alleles. Therefore, there was no conclusive evidence from microsatellites that the groups of individuals characterized by different Clade-II mitochondrial lineages at a given location belong to separate gene pools: hence, one cannot reject the hypothesis that they belong to the same one species, but larger sample sizes of both individuals and loci are needed to further explore the question of reproductive isolation in western Pacific S. commerson.

It is generally hypothesized that highly divergent intra-specific lineage originate either from recent admixture of formerly isolated populations or from hybridization and introgression of mtDNA from one species into another [START_REF] Avise | Intraspecific phylogeography: the mitochondrial DNA bridge between population genetics and systematics[END_REF]. The co-occurrence of discontinuous mtDNA lineages at a given geographic site ("Category II" of [START_REF] Avise | Intraspecific phylogeography: the mitochondrial DNA bridge between population genetics and systematics[END_REF] is not common. This has nevertheless been observed in two other Scombridae species, the bigeye tuna Thunnus obesus [START_REF] Durand | Nuclear and mitochondrial DNA markers indicate unidirectional gene flow of Indo-Pacific to Atlantic bigeye tuna (Thunnus obesus) populations, and their admixture off southern Africa[END_REF]Gonzales, Beerli & Zardoya, 2008) and the carite, Scomberomorus brasiliensis [START_REF] Gold | Population structure of carite (Scomberomorus brasiliensis) in waters offshore of Trinidad and northern Venezuela[END_REF] as well as a few other pelagic fishes [START_REF] Magoulas | Mitochondrial DNA phylogeny and the reconstruction of the population history of a species: the case of the European anchovy (Engraulis encrasicolus)[END_REF][START_REF] Rosel | Mitochondrial control region variability and global population structure in the swordfish, Xiphias gladius[END_REF][START_REF] Nesbø | Phylogeography and population history of Atlantic mackerel (Scomber scombrus L.): a genealogical approach reveals genetic structuring among the eastern Atlantic stocks[END_REF][START_REF] Graves | Stock structure of the world"s istiophorid billfishes: a genetic perspective[END_REF][START_REF] Viñas | Inter-oceanic genetic differentiation among albacore (Thunnus alalunga) populations[END_REF][START_REF] Rohfritsch | Genetic structure of Indian scad mackerel Decapterus russelli: Pleistocene vicariance and secondary contact in the Central Indo-West Pacific Seas[END_REF], and generally is thought to result from secondary contact between formerly geographically isolated populations, although the alternative hypothesis of sympatric divergence has been also proposed. Assuming a mutation rate of approximately 10% per million years for the control-region [START_REF] Bowen | Shallow mtDNA coalescence in Atlantic pygmy angelfishes (genus Centropyge) indicates a recent invasion from the Indian Ocean[END_REF], intraspecific net divergences among sub-clades within western Pacific S. commerson (9.0% to 11.8%) would imply that the lineages started to diverge between ca. 450,000 and ca. 590,000 years ago. This dating designates the lowering of sea level within the last five or six Milankovitch glacial cycles as a possible cause for the geographic isolation of S. commerson populations in the Indo-West Pacific region. Secondary contact would have occurred during one or another of the subsequent rises in sea level.

DO MIGRATORY CAPABILITIES ENHANCE GEOGRAPHIC STRUCTURE IN S. COMMERSON?

The present survey of genetic variation in S. commerson revealed deeply divergent mitochondrial clades associated with strong geographic structure at both mitochondrial and nuclear-DNA loci, not only at the scale of the geographic distribution of the species, but also at the regional scale. At the Indo-Pacific scale, highly divergent clades in S. commerson and correlated morphological differences are indicative of cryptic species. At the regional scale, our results showed the occurrence of independent populations within the Indo-Malay-Papua archipelago, confirming Sulaiman and Ovenden"s (2009) preliminary results, and also within the southwestern Pacific region. Despite having a pelagic lifestyle in both adults and larvae, the degree of geographic differentiation in S. commerson was much higher than generally observed in pelagic species, with the notable exceptions of Decapterus russelli (Table 5). In particular, this degree of geographic partition contrasts with the patterns generally observed in other Scomberomorus species, where little or no genetic variation has been detected distribution-wide (Table 6). Although genetic differences were evident between populations of both S. munroi and S. queenslandicus sampled along the northeastern Australian shores [START_REF] Begg | Genetic variation and stock structure of school mackerel and spotted mackerel in northern Australian waters[END_REF], the magnitude of those differences as expressed by Wright"s Fst, was the same as that in S. commerson sampled in the Persian Gulf and Oman Sea, but still one order lower than Fst values for S. commerson in the tropical southwestern Pacific (Table 6).

It might be sensible to assume that the extreme migrating ability of pelagic fishes entail wide-scale geographic homogeneity in allele frequencies. Although S. commerson occurs in inshore waters and presumably does not cross large expanses of ocean as do tunas and billfishes, the level of geographic difference observed at the regional scale in S. commerson (present results) is striking: this suggests that migrating ability might rather be associated with increased potential for homing, hence for reproductive isolation. [START_REF] Nei | Molecular evolutionary genetics[END_REF], S = number of polymorphic sites, π = nucleotide diversity [START_REF] Nei | Molecular evolutionary genetics[END_REF], and k = average number of nucleotide differences between two sequences [START_REF] Tajima | Evolutionary relationship of DNA sequences in finite populations[END_REF]. For the H-test [START_REF] Depaulis | Neutrality tests based on the distribution of haplotypes under an infinitesite model[END_REF], the probability that Hd sim <Hd obs is reported. The value of Tajima"s D test [START_REF] Tajima | Statistical method for testing the neutral mutation hypothesis by DNA polymorphism[END_REF]

  ) with no bootstrap support. Sub-clade IIa consisted of haplotypes exclusively found in New Caledonia. Sub-clade IIb comprised haplotypes sampled exclusively in the Coral Sea and in West Papua. Sub-clade IIc comprised haplotypes sampled exclusively in the East and South China Seas and adjacent Java Sea. Sub-clade IId comprised haplotypes exclusively from northern Australia and the Coral Sea. Haplotypes from the central Haplogroup ii were distributed from the South China Sea to New Caledonia and were dominant in the eastern part of the Indo-Malay-Papuan archipelago. Sub-clades IIa, IIc, and IId were strongly supported, with bootstrap scores from 81 to 98%. Sub-clade IIb was poorly supported statistically, presumably because of the low number of mutations that separated it from the central Haplogroup ii. Nevertheless, Sub-clade IIb was distinct, as it mostly consisted of haplotypes arranged in a star-like fashion around a dominant haplotype.

Figure 2 .

 2 Figure 2. Narrow-barred Spanish mackerel, Scomberomorus commerson. Median-joining parsimony network (Bandelt, Forster & Röhl, 1999) of control region haplotypes. Groups of haplotypes delineated according to genetic proximity, with indication of area of occurrence; two main clades numbered I and II, the latter with sub-clades IIa, IIb, IIc and IId radiating from a central haplogroup II. Branch length proportional to number of mutational steps; closed circles represent individual haplotypes, their area being proportional to their frequency in the total sample; arrow indicates root. Bootstrap support (Neighbour-Joining algorithm; Kimura-2 parameter distances; 1000 resampling runs; Tamura et al., 2007) was: 100% for clade I; 98% for sub-clade IIa; 32% for sub-clade IIb; 81% for sub-clade IIc; 98% for Sub-clade IId. Scale bar: 5 mutational steps.

Figure 3 .

 3 Figure 3. Narrow-barred Spanish mackerel, Scomberomorus commerson. Neighbor-Joining tree (Tamura-3 parameter distances; MEGA 5) of composite mitochondrial sequences (281 bp cytochrome b gene + 392 bp control region). Arrow indicates placement of root.

Figure 4 .

 4 Figure 4. Narrow-barred Spanish mackerel, Scomberomorus commerson. Correspondence analysis: projection on the two dimensions defined by axis 1 and axis 3, of 86 individuals sampled from Bali (BALI: N=6), Java Sea (JAVA: N=4) and West Papua (WPAP: N=10), and New Caledonia (NCAL: N=66), characterized by their genotype at eight microsatellite loci. Multiple-nuclear locus estimates of genetic differentiation were the following: JAVA vs. BALI: ^θ=0.014, P=0.369; (JAVA + BALI) vs. WPAP: ^θ=0.231, P<0.001; (JAVA + BALI) vs. NCAL: ^θ=0.311, P<0.001; WPAP vs NCAL: ^θ=0.202, P<0.001.

Table 1 .

 1 Pairwise  ST estimates based on sequences of the 5"end mitochondrial control region among narrow-barred Spanish mackerel (Scomberomorus commerson) samples (above diagonal). Super-sample "Persian Gulf+Oman Sea" (PG+OS) comprises samples AUH, BAH, DIB, IRN, KUW, OMN and RAK of[START_REF] Hoolihan | Mitochondrial DNA analyses of narrow-barred Spanish mackerel (Scomberomorus commerson) suggest a single genetic stock in the ROPME sea area (Arabian Gulf, Gulf of Oman, and Arabian Sea)[END_REF]; samples 1-12 as in[START_REF] Sulaiman | Population genetic evidence for the east-west division of the narrowbarred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace's Line[END_REF]; else: see Fig.1. n, number of sequences (in brackets). Significance levels (based on 10,000 permutations of haplotypes among samples) are indicated below diagonal: NS non significant; * P<0.05; ** P<0.010; *** P<0.001. Above diagonal, bold: values remaining significant after sequential Bonferroni correction[START_REF] Rice | Analyzing tables of statistical tests[END_REF]

	Sample	(n)	PG+OS	1	2	3	4	5	6	7	8 JAVA	BALI	9	10	11	12 WPAP NCAL
	PG + OS (193)	-	0.772	0.770	0.784	0.746	0.735	0.763	0.744	0.780	0.788	0.747	0.800	0.773	0.749	0.785	0.787	0.765
	1	(2)	***	-	0.002	0.091	-0.166	0.081	-0.059	0.470	-0.077	0.352	0.213	0.932	0.684	0.692	0.645	0.829	0.670
	2	(2)	***	NS	-	0.326	-0.102	0.133	0.071	0.526	0.009	0.433	0.275	0.965	0.715	0.729	0.664	0.851	0.657
	3	(2)	***	NS	NS	-	-0.197	0.064	0.051	0.438	-0.215	0.299	0.241	0.895	0.667	0.678	0.623	0.811	0.673
	4	(4)	***	NS	NS	NS	-	-0.092	-0.119	0.197	-0.124	0.275	0.139	0.651	0.481	0.449	0.493	0.657	0.573
	5	(5)	***	NS	NS	NS	NS	-	-0.055	-0.033	0.118	0.343	0.144	0.466	0.309	0.195	0.335	0.477	0.421
	6	(5)	***	NS	NS	NS	NS	NS	-	0.139	0.056	0.327	0.149	0.510	0.451	0.361	0.485	0.567	0.569
	7	(4)	***	NS	NS	NS	NS	NS	NS	-	0.473	0.590	0.307	0.332	0.264	-0.077	0.355	0.376	0.332
	8	(3)	***	NS	NS	NS	NS	NS	NS	NS	-	0.314	0.268	0.865	0.669	0.674	0.655	0.804	0.675
	JAVA	(4)	***	NS	NS	NS	*	*	*	*	*	-	0.028	0.860	0.735	0.713	0.712	0.764	0.668
	BALI	(6)	***	NS	NS	NS	NS	NS	NS	NS	NS	NS	-	0.587	0.517	0.436	0.546	0.463	0.518
	9	(5)	***	*	*	*	*	**	**	*	*	**	*	-	0.629	0.432	0.626	0.533	0.465
	10	(5)	***	*	*	*	*	*	**	*	*	**	**	**	-	0.295	0.308	0.585	0.367
	11	(5)	***	*	*	*	*	NS	*	NS	*	**	*	**	*	-	0.424	0.332	0.251
	12	(5)	***	*	*	*	**	**	**	*	*	**	**	**	*	**	-	0.609	0.375
	WPAP	(8)	***	*	*	*	**	***	***	**	**	**	*	***	***	***	***	-	0.282
	NCAL	(194)	***	***	***	***	***	***	***	**	***	***	***	***	**	**	***	**	-

Table 2 .

 2 Analysis of molecular variance (AMOVA) among samples of Scomberomorus commerson based on partial sequences (310 bp) of the mitochondrial control region. Samples were grouped on a geographic basis (see Fig.1) as following: Persian Gulf + Oman Sea (samples AUH, BAH, DIB, IRN, KUW, OMN and RAK); East China Sea (1); South China Sea + Malacca Strait (2-8); Java Sea + Bali (JAVA, BALI); Timor Sea + Arafura Sea (9-11); West Papua (WPAP); CoralSea (12, NCAL)

	Source of variation	d.f.	Sum of squares	Variance	% variation	P-value
	Among groups	6	5787.59	components Va=20.49	72.79	<0.0001
	Among populations within groups	20	266.97	Vb= 0.35	1.23	0.0014
	Within groups	424	3100.91	Vc= 7.31	25.98	<0.0001
	Total	450	9155.48	28.15

Table 3 .

 3 Genetic diversity and results of neutrality tests in populations of Scomberomorus commerson across the Indo-Pacific. N = number of individuals, H = number of haplotypes, Hd = haplotype diversity

ACKNOWLEDGEMENTS

We thank P.H. Barber and J.R. Ovenden for encouragement and stimulating discussions, and two anonymous referees for improvement of the final version. Samples from New Caledonia were provided by our colleagues M. Leopold and D. Ponton. V.P. Buonaccorsi kindly provided the original Fst values for S. maculatus. Funded by UR 128 and UR 227 of Institut de recherche pour le développement and by Programme d"évaluation des ressources marines de la zone économique exclusive de Nouvelle-Calédonie (ZoNéCo), Nouméa, New Caledonia.