Axelle Zacaï
email: axelle.zacai@gmail.com

Emmanuel Fara

Arnaud Brayard

Rémi Laffont

Jean-Louis Dommergues

Christian Meister

Phylogenetic conservatism of species range sizes is the combined outcome of phylogeny and environmental stability

Keywords: ammonites, Early Jurassic, environment, phylogenetic conservatism, phylogeny, provincialism, species range size

Aim

To test for the phylogenetic conservatism of geographic range size and to explore the effect of the environment on this potential conservatism.

Location

The western Tethys Ocean and its surroundings (present-day Europe, the Middle East and North Africa) during the early Pliensbachian (Early Jurassic).

Methods

Using 104 localities and 1765 occurrences of ammonite species, we estimated geographic range sizes using the extent of occurrence and the latitudinal range. The phylogenetic conservatism of range sizes was tested using Moran's I index which measures phylogenetic autocorrelation, and Pagel's λ which indicates whether a phylogeny correctly predicts covariance patterns among taxa on a given trait according to a Brownian evolution model. We conducted these analyses for two neighbouring provinces with contrasting environmental features (Mediterranean and North West European). We also explored scale effects by considering the whole western Tethys and two temporal resolutions (chronozone and substage).

Results A marked difference in phylogenetic signal is observed between Mediterranean (MED) and North West European (NWE) species; the range size of MED species is more frequently phylogenetically conserved than that of NWE species. No phylogenetic conservatism of species range size is observed during the last chronozone of the early Pliensbachian which is characterized by numerous palaeoclimatic and palaeoenvironmental changes.

Main conclusions Species range size may be partly determined by phylogeny, but this phylogenetic conservatism is modulated by environmental stability. The phylogenetic signal of species range size may be labile through time within the same lineage and may differ between contemporaneous species of the same group. This lability stems from the fact that species range size results from a complex interplay of intrinsic and extrinsic factors. It seems that only some combinations of these factors may lead to range size conservatism.

INTRODUCTION

Geographic range size is a fundamental ecological and evolutionary feature of species [START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF][START_REF] Gaston | The sizes of species' geographic ranges[END_REF]. Interest in measuring species range sizes and appraising its determinants has grown over the past decade, along with concern about species extinctions related to climate change and human activities [START_REF] Kiessling | Geographical distribution and extinction risk: lessons from Triassic-Jurassic marine benthic organisms[END_REF][START_REF] Mace | Quantification of extinction risk: IUCN's system for classifying threatened species[END_REF][START_REF] Joppa | Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment[END_REF]. Range size is postulated to be a good predictor of extinction risk [START_REF] Iucn | IUCN red list categories and criteria: version 3.1. Prepared by the IUCN Species Survival Commission[END_REF][START_REF] Lawton | Extinction rates[END_REF][START_REF] Rosenzweig | Species diversity in space and time[END_REF][START_REF] Gaston | Species-range size distributions: products of speciation, extinction and transformation[END_REF][START_REF] Kiessling | Geographical distribution and extinction risk: lessons from Triassic-Jurassic marine benthic organisms[END_REF] and as such, it is one of five criteria used by the International Union for Conservation of Nature to establish the Red List of Threatened Species [START_REF] Iucn | IUCN red list categories and criteria: version 3.1. Prepared by the IUCN Species Survival Commission[END_REF]. Following [START_REF] Rapoport | Areography: geographical strategies of species[END_REF] work on areography, the definition and measurement of species geographic ranges have been intensively investigated over the past two decades [START_REF] Gaston | Rarity[END_REF][START_REF] Gaston | Species-range-size distributions: patterns, mechanisms and implications[END_REF][START_REF] Gaston | Species-range size distributions: products of speciation, extinction and transformation[END_REF][START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF][START_REF] Brown | Biogeography[END_REF]Gaston & Chown, 1999;[START_REF] Gaston | The sizes of species' geographic ranges[END_REF][START_REF] Tomašových | Nonlinear thermal gradients shape broad-scale patterns in geographic range size and can reverse Rapoport's rule[END_REF]. These studies distinguish two main measurements of species range: the extent of occurrence, i.e. area between the outermost limits to a species occurrence; and the area of occupancy, i.e. area over which the species is actually found. However, as the quantification of species range size depends on the resolution of available data, it is sometimes estimated using other variables such as the number of occurrences (e.g. [START_REF] Finnegan | Paleontological baselines for evaluating extinction risk in the modern oceans[END_REF][START_REF] Longrich | Severe extinction and rapid recovery of mammals across the Cretaceous-Paleogene boundary, and the effects of rarity on patterns of extinction and recovery[END_REF], maximal latitudinal range [START_REF] Qian | Geographical distribution and ecological conservatism of disjunct genera of vascular plants in eastern Asia and eastern North America[END_REF][START_REF] Powell | Latitudinal diversity gradients for brachiopod genera during late Palaeozoic time: links between climate, biogeography and evolutionary rates[END_REF][START_REF] Waldron | Null models of geographic range size evolution reaffirm its heritability[END_REF], or number of cells/quadrats occupied by a taxon [START_REF] Webb | On the heritability of geographic range sizes[END_REF][START_REF] Qian | Geographical distribution and ecological conservatism of disjunct genera of vascular plants in eastern Asia and eastern North America[END_REF][START_REF] Foote | On the bidirectional relationship between geographic range and taxonomic duration[END_REF]. This diversity of approaches for quantifying species range size is associated with a lack of consensus about its determinants, especially the role of phylogeny. Using data from Late Cretaceous molluscs and by comparing the range sizes of sister species pairs, [START_REF] Iucn | IUCN red list categories and criteria: version 3.1. Prepared by the IUCN Species Survival Commission[END_REF] was among the first authors to suggest the "heritability" of species range size, i.e. the tendency for closely related species to share similar range sizes. However, his results have been intensely debated [START_REF] Webb | On the heritability of geographic range sizes[END_REF][START_REF] Hunt | Species-level heritability reaffirmed: a comment on "On the heritability of geographic range sizes[END_REF][START_REF] Waldron | Null models of geographic range size evolution reaffirm its heritability[END_REF], leading to further investigations on this issue at the crossroad between macroevolution and macroecology. Several studies documented phylogenetic conservatism of range size in different clades [START_REF] Freckleton | Phylogenetic analysis and comparative data: a test and review of evidence[END_REF][START_REF] Blackburn | The influence of spatial resolution on macroecological patterns of range size variation: a case study using parrots (Aves: Psittaciformes) of the world: range size resolution in parrots[END_REF][START_REF] Jones | Age and area revisited: identifying global patterns and implications for conservation[END_REF]Freckleton & Jetz, 2009), but other works found that range size was not a species-level conserved trait [START_REF] Gaston | Age, area and avian diversification[END_REF][START_REF] Webb | Rarity and Phylogeny in Birds. Biotic Homogenization[END_REF][START_REF] Freckleton | Phylogenetic analysis and comparative data: a test and review of evidence[END_REF][START_REF] Böhning-Gaese | Range size: disentangling current traits and phylogenetic and biogeographic factors[END_REF]. Table 1 summarizes these contrasting observations together with the methods used to assess the phylogenetic signal in range size. Most of these studies focused on phylogenetic conservatism, but only a few of them considered the role of environmental parameters in shaping species ranges [START_REF] Böhning-Gaese | Range size: disentangling current traits and phylogenetic and biogeographic factors[END_REF][START_REF] Kiessling | Geographical distribution and extinction risk: lessons from Triassic-Jurassic marine benthic organisms[END_REF][START_REF] Mouillot | Spatial overlap enhances geographic range size conservatism[END_REF][START_REF] Abellán | Geographic location and phylogeny are the main determinants of the size of the geographical range in aquatic beetles[END_REF]. This is all the more surprising as the range size of a species likely results from a complex interplay of intrinsic and extrinsic factors. Even if it is difficult to analyse their combined effects due to the lack of adequate datasets, the potential influence of parameters other than phylogeny should be considered. In addition, except for a few studies on Mesozoic marine organisms and Cenozoic mammals [START_REF] Iucn | IUCN red list categories and criteria: version 3.1. Prepared by the IUCN Species Survival Commission[END_REF][START_REF] Kiessling | Geographical distribution and extinction risk: lessons from Triassic-Jurassic marine benthic organisms[END_REF][START_REF] Carotenuto | Occupancy, range size, and phylogeny in Eurasian Pliocene to Recent large mammals[END_REF], most research on relationships between species range size and phylogeny has focused on extant taxa (Table 1). Since palaeontological data offer an extensive temporal perspective on biogeographical patterns, climate and environmental changes, they are pertinent for investigating the relative roles of phylogeny and environment in determining species range size. For this purpose, an appropriate palaeontological dataset should be composed of closely related species evolving within at least two contrasting ecoregions.

Here we investigate the phylogenetic conservatism of geographic range size for a group of ammonites (externally-shelled cephalopods) from the early Pliensbachian (Early Jurassic). These ammonites lived in the western part of the Tethys Ocean which corresponds to present-day Europe, the Middle East and North Africa (Fig. 1). These species are distributed within two environmentally contrasting provinces [START_REF] Smith | Plate tectonics and paleobiogeography; Early Jurassic (Pliensbachian) endemism and diversity[END_REF][START_REF] Dommergues | Endemism as a palaeobiogeographic parameter of basin history illustrated by early-and mid-Liassic peri-Tethyan ammonite faunas[END_REF][START_REF] Wignall | The timing of paleoenvironmental change and causeand-effect relationships during the Early Jurassic mass extinction in Europe[END_REF][START_REF] Arias | Pliensbachian-Toarcian ostracod biogeography in NW Europe: evidence for water mass structure evolution[END_REF]Dera et al., 2009a[START_REF] Dera | a) Climatic ups and downs in a disturbed Jurassic world[END_REF][START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]. The northern province is characterized by a shallow epicontinental sea surrounded by continents and punctuated by numerous archipelagos, whereas the southern province corresponds to a series of deep basins opened on the Tethys Ocean (Fig. 1). The southern province is known to be more physically stable than the northern province [START_REF] Hallam | Diversity and density characteristics of Pliensbachian-Toarcian molluscan and brachiopod faunas of the North Atlantic margins[END_REF][START_REF] Smith | Plate tectonics and paleobiogeography; Early Jurassic (Pliensbachian) endemism and diversity[END_REF]Dera et al., 2011b). Additionally, several important climatic and environmental disturbances are recorded at the end of the early Pliensbachian (i.e. during the Davoei chronozone) in the northern province: (i) an increase in sea-surface temperatures [START_REF] Rosales | Paleotemperature variations of Early Jurassic seawater recorded in geochemical trends of belemnites from the Basque-Cantabrian basin, northern Spain[END_REF]Dera et al., 2009a, b;2011a;Price et al., 2016;[START_REF] Bougeault | Climatic and palaeoceanographic changes during the Pliensbachian (Early Jurassic) inferred from clay mineralogy and stable isotope (CO) geochemistry (NW Europe)[END_REF], (ii) a sea-level increase [START_REF] Hallam | A review of the broad pattern of Jurassic sea-level changes and their possible causes in the light of current knowledge[END_REF]Bougeault et al., in press), (iii) more humid climatic conditions (Dera et al., 2009a;Bougeault et al., in press) and (iv) a potential incursion of warm water masses from the Tethys Ocean (Dera et al., 2009b[START_REF] Dera | Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea[END_REF]. A concomitant decline in ammonite species richness is documented [START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF][START_REF] Dera | High-resolution dynamics of Early Jurassic marine extinctions: the case of Pliensbachian-Toarcian ammonites (Cephalopoda)[END_REF]. Based on this environmental context, we address the following questions: (i) is species range size a phylogenetically conserved trait? (ii) Can the environment affect the phylogenetic signal of range size conservatism? Since phylogenetic range size conservatism is more likely to occur when species share common environmental conditions [START_REF] Mouillot | Spatial overlap enhances geographic range size conservatism[END_REF], we hypothesize that species range size will be more phylogenetically conserved when environmental conditions are spatio-temporally stable.

MATERIAL AND METHODS

Dataset

We used Dommergues et al.'s dataset (2009) on early Pliensbachian (Early Jurassic,c. 191.36 ± 1 Ma to 187.6 ± 1 Ma, [START_REF] Gradstein | The Geologic Time Scale[END_REF][START_REF] Ogg | A Concise Geologic Time Scale[END_REF]Fig. 1A) ammonites which consists of 214 revised species distributed among 104 fossil localities in the western Tethys and adjacent areas (Fig. 1B).

Palaeocoordinates for each fossil locality were calculated following the procedure described in Appendix S1 (Supporting Information). The early Pliensbachian is known as a time of marked faunal provincialism between two provinces: the Mediterranean Tethys (MED) in the south and Northwest Europe (NWE) in the north (Fig. 1B). These two contrasting provinces have been recognized for ammonites [START_REF] Neumayr | Ueber Jura-Provinzen[END_REF][START_REF] Donovan | The geographical distribution of Lower Jurassic ammonites in Europe and adjacent areas[END_REF][START_REF] Hallam | Faunal realms and facies in the Jurassic[END_REF][START_REF] Dommergues | Le provincialisme des ammonites nord-ouest européennes au Lias moyen. Une crise faunique sous contrôle paléogéographique[END_REF][START_REF] Geczy | Jurassic ammonite provinces of Europe[END_REF][START_REF] Dommergues | Area of mixed marine faunas between two major paleogeographical realms, exemplified by the Early Jurassic (Late Sinemurian and Pliensbachian) ammonites in the Alps[END_REF][START_REF] Meister | Les ammonites du Lias moyen (Pliensbachien) de la Néotéthys et de ses confins; compositions fauniques, affinités paléogéographiques et biodiversité[END_REF][START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF], brachiopods [START_REF] Ager | Mesozoic brachiopoda. Atlas of Palaeobiogeography[END_REF][START_REF] Vörös | Provinciality of the Mediterranean Lower Jurassic brachiopod fauna: causes and platetectonic implications[END_REF], bivalves [START_REF] Hallam | Jurassic bivalve biogeography[END_REF][START_REF] Liu | Bivalve provinces in the proto-Atlantic and along the southern margin of the Tethys in the Jurassic[END_REF], ostracods [START_REF] Lord | Ostracoda of the Early Jurassic Tethyan Ocean. Evolutionary biology of ostracoda: its fundamentals and applications[END_REF][START_REF] Arias | Palaeozoogeography of Western European Lower Jurassic (Pliensbachian and Toarcian) Ostracoda[END_REF] and belemnites [START_REF] Doyle | Lower Jurassic-Lower Cretaceous belemnite biogeography and the development of the Mesozoic Boreal Realm[END_REF][START_REF] Doyle | Aspects of the distribution of Early Jurassic belemnites[END_REF]. In addition to this faunal differentiation, the MED and NWE provinces are characterized by contrasting palaeogeographies and palaeoenvironments. The NWE province corresponds to an epicontinental sea not exceeding 200 m in depth, surrounded by continents and punctuated by numerous archipelagos (Fig. 1B). This singular configuration led to a strong influence of numerous perturbations, such as freshwater influxes, nutrient inputs, anoxia, incursions of cold and warm waters and changes in water currents [START_REF] Rosales | Paleotemperature variations of Early Jurassic seawater recorded in geochemical trends of belemnites from the Basque-Cantabrian basin, northern Spain[END_REF][START_REF] Wignall | The timing of paleoenvironmental change and causeand-effect relationships during the Early Jurassic mass extinction in Europe[END_REF][START_REF] Arias | Pliensbachian-Toarcian ostracod biogeography in NW Europe: evidence for water mass structure evolution[END_REF][START_REF] Mcarthur | Basinal restriction, black shales, Re-Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event[END_REF]Dera et al., 2009a[START_REF] Dera | a) Climatic ups and downs in a disturbed Jurassic world[END_REF][START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]. Conversely, the MED province corresponds to deep interconnected basins influenced by warm and nutrient-rich surface waters from the Tethys Ocean and represents more physically stable open-marine palaeoenvironments [START_REF] Hallam | Diversity and density characteristics of Pliensbachian-Toarcian molluscan and brachiopod faunas of the North Atlantic margins[END_REF][START_REF] Smith | Plate tectonics and paleobiogeography; Early Jurassic (Pliensbachian) endemism and diversity[END_REF][START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]Dera et al., 2011bDera et al., ). et al. (2012) ) built upon this work by further introducing a species-level phylogenetic hypothesis (Fig. 2) that they used to demonstrate phylogenetic clustering of species extinctions during this interval. Here we use this phylogeny to investigate whether closely related species exhibit more similar range sizes than expected by chance and whether environmental stability can alter this phylogenetic signal. Species occurrences are documented for the three successive chronozones of the early Pliensbachian, i.e.

Jamesoni, Ibex and Davoei [START_REF] Page | The Lower Jurassic of Europe: its subdivision and correlation[END_REF]Fig. 1A).

Range size phylogenetic conservatism

We tested the phylogenetic conservatism of species range size using Moran's index of spatial autocorrelation I [START_REF] Moran | Notes on continuous stochastic phenomena[END_REF][START_REF] Gittleman | Adaptation: statistics and a null model for estimating phylogenetic effects[END_REF], as implemented in the gearymoran function in the ade4 package [START_REF] Chessel | The ade4 package-I-One-table methods[END_REF][START_REF] Dray | The ade4 package-II: Two-table and K-table methods[END_REF] in R ( v.3.0.2; R Development Core Team, 2010). We chose this index because (i) it is frequently used to test for phylogenetic autocorrelation (e.g. [START_REF] Gittleman | Adaptation: statistics and a null model for estimating phylogenetic effects[END_REF][START_REF] Gittleman | Detecting Ecological Pattern in Phylogenies. Biodiversity dynamics: turnover of populations, taxa, and communities[END_REF][START_REF] Jones | Age and area revisited: identifying global patterns and implications for conservation[END_REF][START_REF] Hardy | Deep-time phylogenetic clustering of extinctions in an evolutionarily dynamic clade (Early Jurassic ammonites)[END_REF], (ii) it applies to whole phylogenies rather than species-pairs [START_REF] Harmon | Poor statistical performance of the Mantel test in phylogenetic comparative analyses[END_REF][START_REF] Abellán | Geographic location and phylogeny are the main determinants of the size of the geographical range in aquatic beetles[END_REF], (iii) it does not imply an evolutionary model [START_REF] Münkemüller | How to measure and test phylogenetic signal[END_REF], (iv) it is broadly insensitive to tree size and tree balance [START_REF] Lockwood | A metric for analyzing taxonomic patterns of extinction risk[END_REF] and polytomies have very small effects on it [START_REF] Münkemüller | How to measure and test phylogenetic signal[END_REF] and (v) it is non-parametric as implemented in gearymoran. As this index is not based on a Brownian model of trait evolution, its values cannot be directly compared across studies [START_REF] Münkemüller | How to measure and test phylogenetic signal[END_REF]. The null hypothesis of no phylogenetic signal was tested for significance using 1000 random permutations of range size values across the tips of the phylogenetic tree. Moran's I varies from -1 to +1, with positive values indicating that the trait of interest is more similar than expected by chance and negative values indicating an absence of correlation between the trait and inter-species phylogenetic distance [START_REF] Paradis | Analysis of phylogenetics and evolution with R[END_REF]p. 210). We also assessed the phylogenetic signal of range size conservatism using Pagel's λ [START_REF] Pagel | Inferring the historical patterns of biological evolution[END_REF][START_REF] Freckleton | Phylogenetic analysis and comparative data: a test and review of evidence[END_REF], as implemented in the phylosig function in the phytools package [START_REF] Revell | Phytools: an R package for phylogenetic comparative biology (and other things)[END_REF]. This index indicates whether the phylogeny correctly predicts covariance patterns among species on a given trait according to a Brownian model of character evolution [START_REF] Felsenstein | Phylogenies and the comparative method[END_REF][START_REF] Harvey | The comparative method in evolutionary biology[END_REF]. A value of λ = 0 indicates a trait evolution that is independent of phylogeny, whereas a value of λ = 1 indicates a trait evolving according to a Brownian motion along the phylogeny. Intermediate values of λ correspond to traits that have evolved according to a process in which the effect of phylogeny is weaker than in the Brownian model [START_REF] Freckleton | Phylogenetic analysis and comparative data: a test and review of evidence[END_REF]. Compared to Moran's I, Pagel's λ is less adapted to our data because (i) it implies a model of trait evolution that may not correspond to the evolution of ammonite traits and (ii) it requires a normal distribution of the variable tested (see following sections).

The use of these two indices requires quantification of inter-species phylogenetic distances. In the absence of branch length information, all species are positioned at the same distance from the root, making the early Pliensbachian ammonite phylogenetic tree ultrametric (Fig. 2). Inter-species phylogenetic distances were obtained after slicing the phylogeny at regular nodal depths, with the most closely-related species being at a distance of two units (see Corey &Waite, 2008 and[START_REF] Hardy | Deep-time phylogenetic clustering of extinctions in an evolutionarily dynamic clade (Early Jurassic ammonites)[END_REF] for similar approaches).

For both extant and extinct species, the actual geographic range size is a hardly accessible feature as its estimation depends on the sampling effort (e.g. De Silva & Medellín, 2008;[START_REF] Fritz | Diversity in time and space: wanted dead and alive[END_REF][START_REF] Yang | Geographical sampling bias in a large distributional database and its effects on species richness-environment models[END_REF]. However, ammonites are among the most frequently preserved fossil organisms because of their relatively thick shell and their very high abundance in Mesozoic seas. Furthermore, our dataset is one of the most highly resolved among available fossil datasets, both in terms of space and time [START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]. Consequently, we estimated species range sizes using two variables, the extent of occurrence (i.e. minimum convex polygon for species with at least three occurrences; [START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF] and the latitudinal range (for species with at least two occurrences). These two variables correspond to "maximal" species range sizes as they are calculated based on the sum of species occurrences for the early Pliensbachian and for each chronozone. Thus, they do not represent instantaneous ranges but rather the whole range explored by a species during its lifetime or during a specific time interval. The extent of occurrence was calculated using the ahull function in the alphahull package [START_REF] Pateiro-López | Generalizing the convex hull of a sample: the R package alphahull[END_REF] in R (v.3.0.2; R Development Core Team, 2010). For species range size calculations at the chronozone scale, we only consider occurrences observed in the chronozone of interest (Appendix S2). We also evaluated the robustness of range size phylogenetic conservatism by removing a given percentage of species occurrences 1000 times and by comparing remain unchanged (see Appendix S2).

While conducting the analyses, we tested whether these two variables yielded consistent signals of phylogenetic conservatism. The frequency distribution of geographic range sizes tends to be strongly right-skewed for extant and fossil marine species [START_REF] Iucn | IUCN red list categories and criteria: version 3.1. Prepared by the IUCN Species Survival Commission[END_REF][START_REF] Jablonski | From regional to total geographic ranges: testing the relationship in Recent bivalves[END_REF][START_REF] Mcallister | Mapping and GIS analysis of the global distribution of coral reef fishes on an equal-area grid[END_REF][START_REF] Kiessling | Geographical distribution and extinction risk: lessons from Triassic-Jurassic marine benthic organisms[END_REF][START_REF] Powell | Latitudinal diversity gradients for brachiopod genera during late Palaeozoic time: links between climate, biogeography and evolutionary rates[END_REF][START_REF] Foote | On the bidirectional relationship between geographic range and taxonomic duration[END_REF][START_REF] Myers | Greenhouse biogeography: the relationship of geographic range to invasion and extinction in the Cretaceous Western Interior Seaway[END_REF], as for most terrestrial assemblages [START_REF] Blackburn | Spatial patterns in the geographic range sizes of bird species in the New World[END_REF][START_REF] Gaston | Age, area and avian diversification[END_REF][START_REF] Gaston | Species-range size distributions: products of speciation, extinction and transformation[END_REF][START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF]. Our dataset is no exception (Fig. 3).

We conducted analyses at the province scale. Only species occurring exclusively in one province (hereafter referred as "MED species" and "NWE species") were taken into account. In addition, we explored the phylogenetic conservatism of species range size at the scale of western Tethys. In this case, the dataset is composed of MED species, NWE species and trans-province species (i.e. species that occur in both provinces). Analyses were conducted for the entire early Pliensbachian and for each of the three chronozones considered independently. The scale of the chronozone presents three advantages: (i) it represents the best compromise between a high spatio-temporal resolution and a large sample size [START_REF] Zacaï | Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study[END_REF], (ii) biostratigraphic correlation (i.e. correlation among sedimentary layers based on their fossil content) between the NWE and MED provinces are robust at this scale [START_REF] Dommergues | Area of mixed marine faunas between two major paleogeographical realms, exemplified by the Early Jurassic (Late Sinemurian and Pliensbachian) ammonites in the Alps[END_REF][START_REF] Page | The Lower Jurassic of Europe: its subdivision and correlation[END_REF][START_REF] Zacaï | Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study[END_REF], and (iii) this finer resolution allows us to track potential changes in the phylogenetic conservatism of species range size through successive time intervals. For analyses on chronozone subdatasets, inter-species phylogenetic distances were calculated on subtrees containing only species occurring in the chronozone and/or area of interest (Appendix S1). They are therefore different from those calculated on the complete early Pliensbachian phylogenetic tree (Fig. 2). Similar analyses were also conducted by using subtrees directly extracted from the complete tree, without recalculating inter-species phylogenetic distances in order to estimate the influence of uncertainties on phylogenetic branch lengths (Appendix S1).

Geography can be a confounding factor when investigating phylogenetic autocorrelation [START_REF] Legendre | Spatial autocorrelation: trouble or new paradigm?[END_REF][START_REF] Qian | Geographical distribution and ecological conservatism of disjunct genera of vascular plants in eastern Asia and eastern North America[END_REF][START_REF] Purvis | Phylogenetic approaches to the study of extinction[END_REF][START_REF] Hardy | Deep-time phylogenetic clustering of extinctions in an evolutionarily dynamic clade (Early Jurassic ammonites)[END_REF]. Spatial autocorrelation is a common property of ecological data that can reduce the power of statistical tests because it violates the assumption of sample independence [START_REF] Legendre | Spatial autocorrelation: trouble or new paradigm?[END_REF]. To control for potential spatial autocorrelation of ammonite range sizes, we calculated the geographic range midpoint of each species for each subdataset of interest, and then used these midpoints to calculate triangular matrices of great-circle (i.e. orthodromic) distances between each species pair. We found non-significant Moran's I values for each subdataset analysed (Appendix S3), which means that ammonite species range sizes are not spatially autocorrelated.

RESULTS

At the scale of the early Pliensbachian, species latitudinal range size is phylogenetically conserved in both provinces and for the western Tethys Ocean (Moran's I > 0; p < 0.05; Table 2). The extent of occurrence is phylogenetically conserved for MED and western Tethys species, but not for NWE species (Moran's I < 0; p > 0.05; Table 2). These signals are not maintained through time as shown by analyses at the chronozone scale (Table 2).

MED species show a phylogenetic conservatism of both latitudinal range and extent of occurrence during the Jamesoni and Ibex chronozones but not during the Davoei chronozone. NWE species never show this phylogenetic conservatism, which highly contrasts with the results for MED species. Western Tethys species show phylogenetic conservatism of both latitudinal range and extent of occurrence during the Jamesoni chronozone, extent of occurrence during the Ibex chronozone, and no phylogenetic conservatism during the Davoei chronozone. Therefore, regardless of the spatial scale of analysis, species range size is not phylogenetically conserved during the Davoei chronozone.

Analyses conducted after keeping the same inter-species phylogenetic distances as those of the complete tree show few differences with analyses conducted by recalculating branch lengths: the signal contrast between MED and NWE species is less pronounced and range size is less often conserved in the western Tethys (see Table 2 andTable S3 in Appendix S3). This suggests that potential uncertainties in branch length estimates have little effect on the observed signal of range size conservatism.

Results obtained with Pagel's λ are similar to those obtained with Moran's I (Table 2). The only significant signal of range size conservatism detected for NWE species with Moran's I (i.e. latitudinal range at the scale of the early Pliensbachian) is no longer significant with Pagel's k (Table 2). This underlines the contrast of phylogenetic signal in range size conservatism between the two provinces. The extent of occurrence is no longer phylogenetically conserved for western Tethys species during the early Pliensbachian and the Ibex chronozone, and for the MED species during the Ibex chronozone when using Pagel's λ (Table 2).

In summary: first, both provinces show a marked contrast in the phylogenetic signal, MED species range sizes are more frequently phylogenetically conserved than those of NWE species. Second, species range size is not phylogenetically conserved during the Davoei chronozone.

DISCUSSION

Methodological aspects

Early Pliensbachian ammonites of the western Tethys are characterized by phylogenetic conservatism of their range size. This signal is found with two different indices (Moran's I and Pagel's λ) and with two different methods for calculating phylogenetic branch lengths. The absence of phylogenetic conservatism for NWE species at the chronozone scale may partly result from small sample sizes in the subdatasets (Table 2). NWE species richness is half that of the MED province and this difference does not result from a bias in sampling effort [START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]. However, analyses conducted without recalculating branch lengths for subtrees show that Moran's I can be significant and positive even for small sample sizes (e.g. latitudinal range for NWE species during the Ibex chronozone; Table S3, Appendix S3). As such, the reduced species richness of the NWE province cannot entirely account for the absence of phylogenetic conservatism of range size in this province. [START_REF] Gaston | Species-range size distributions: products of speciation, extinction and transformation[END_REF] proposed different temporal dynamics models of species range size. According to [START_REF] Carotenuto | Occupancy, range size, and phylogeny in Eurasian Pliocene to Recent large mammals[END_REF], most species biogeographic ranges apparently show a maximum range occurring halfway through their duration. In this work, we only deal with maximum species range sizes, i.e. the sum of their occurrences for their entire duration. This might be considered as a source of noise, especially at the chronozone level. However, 74% of the studied early Pliensbachian ammonites have a geological duration of a single chronozone, meaning that most of the "maximal" range sizes used in our analyses are not truncated. This percentage falls to 21% and 6% for a duration of two and three chronozones, respectively. As such, we consider that the use of "maximal" species range sizes is not a source of bias in this work.

Phylogenetic conservatism of species range size

Species range size is a trait defined by a complex interplay of biological and environmental factors including species' dispersal ability, ecological tolerance, inter-specific competition, environmental features and physical barriers (e.g. [START_REF] Brown | Biogeography[END_REF][START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF][START_REF] Böhning-Gaese | Range size: disentangling current traits and phylogenetic and biogeographic factors[END_REF].

As such, phylogenetic conservatism of this macroecological trait probably involves more complex processes than a simple transmission of biological characters from ancestors to descendants. Thus, species range size will be best conserved in a lineage if the transmission of biological characters is associated with a spatio-temporal stability of environmental conditions. This may specifically apply to organisms whose dispersal is largely controlled by the environment, such as ammonites which are supposed to achieve their long-distance dispersal essentially through passive planktonic drift during early juvenile, post-hatching stages [START_REF] Westermann | Ammonoid Life and Habitat. Ammonoid Paleobiology[END_REF][START_REF] Brayard | The Early Triassic ammonoid recovery: paleoclimatic significance of diversity gradients[END_REF][START_REF] Brayard | Guodunites, a low-palaeolatitude and trans-Panthalassic Smithian (Early Triassic) ammonoid genus[END_REF][START_REF] De Baets | Early evolutionary trends in ammonoid embryonic development: evolutionary trends in ammonoid embryos[END_REF][START_REF] Ritterbush | Pelagic palaeoecology: the importance of recent constraints on ammonoid palaeobiology and life history: pelagic palaeoecology of ammonoids[END_REF][START_REF] Naglik | Ammonoid Locomotion. Ammonoid Paleobiology: from anatomy to ecology[END_REF][START_REF] Zacaï | Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study[END_REF]. [START_REF] Mouillot | Spatial overlap enhances geographic range size conservatism[END_REF] raised this point for extant species by suggesting that phylogenetic conservatism of geographic range size is more likely to occur when closely related species share common environmental conditions. Our findings are consistent with this statement. Spatially, species range size conservatism is more pronounced in the MED province which is characterized by physically stable open-marine palaeoenvironments during the early Pliensbachian [START_REF] Hallam | Diversity and density characteristics of Pliensbachian-Toarcian molluscan and brachiopod faunas of the North Atlantic margins[END_REF][START_REF] Smith | Plate tectonics and paleobiogeography; Early Jurassic (Pliensbachian) endemism and diversity[END_REF]Dera et al., 2011b). Conversely, the weak phylogenetic signal in the NWE province (Table 2) probably results from the spatio-temporal instability of its palaeoenvironments. The singular configuration of this province led to a strong influence of numerous perturbations such as freshwater influxes, nutrient inputs, incursions of cold Boreal and warm Tethyan waters, changes in current dynamics, and anoxia [START_REF] Hallam | Diversity and density characteristics of Pliensbachian-Toarcian molluscan and brachiopod faunas of the North Atlantic margins[END_REF][START_REF] Smith | Plate tectonics and paleobiogeography; Early Jurassic (Pliensbachian) endemism and diversity[END_REF][START_REF] Rosales | Paleotemperature variations of Early Jurassic seawater recorded in geochemical trends of belemnites from the Basque-Cantabrian basin, northern Spain[END_REF][START_REF] Wignall | The timing of paleoenvironmental change and causeand-effect relationships during the Early Jurassic mass extinction in Europe[END_REF][START_REF] Arias | Pliensbachian-Toarcian ostracod biogeography in NW Europe: evidence for water mass structure evolution[END_REF][START_REF] Mcarthur | Basinal restriction, black shales, Re-Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event[END_REF]Dera et al., 2009aDera et al., , b, 2011b;;[START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF], all susceptible to modifying ammonite dispersal and ranges.

Temporally, range size is phylogenetically conserved for MED and western Tethys species during the Jamesoni and Ibex chronozones but not during the Davoei chronozone (Table 2). While the first two chronozones do not record any noticeable environmental and climatic changes, the Davoei chronozone is characterized by an increase in sea-surface temperatures of about 4°C in the studied area [START_REF] Rosales | Paleotemperature variations of Early Jurassic seawater recorded in geochemical trends of belemnites from the Basque-Cantabrian basin, northern Spain[END_REF]Dera et al., 2009a, b;2011a;Price et al., 2016), a sea-level increase [START_REF] Hallam | A review of the broad pattern of Jurassic sea-level changes and their possible causes in the light of current knowledge[END_REF], more humid climatic conditions (Dera et al., 2009a) and a potential incursion of warm water masses from the Tethys Ocean into the NWE province (Dera et al., 2009b[START_REF] Dera | Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea[END_REF]. In addition to these climatic and environmental changes, another possible explanation for the absence of a phylogenetic signal in range size conservatism during the Davoei chronozone is the low species richness that characterizes it (Table 2). This genuine decline could be related to an increase in sea water temperature [START_REF] Rosales | Paleotemperature variations of Early Jurassic seawater recorded in geochemical trends of belemnites from the Basque-Cantabrian basin, northern Spain[END_REF]Dera et al., 2009a, b;2011a;[START_REF] Dommergues | Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas[END_REF]Price et al., 2016) and to low origination rates [START_REF] Dera | High-resolution dynamics of Early Jurassic marine extinctions: the case of Pliensbachian-Toarcian ammonites (Cephalopoda)[END_REF].

Overall, this suggests that species range size may be partly determined by phylogeny (i.e. biological/physiological heritable characters), but that phylogenetic conservatism is probably modulated by environmental stability through space and time. Our results echo the concept of potential range (i.e. area within which a species would be found if all dispersal limitations were overcome) vs. realized range (i.e. smaller area within which a species does occur; [START_REF] Udvardy | Dynamic zoogeography, with special reference to land animals[END_REF][START_REF] Gaston | Rarity[END_REF][START_REF] Gaston | The Structure and Dynamics of Geographic Ranges[END_REF]. Given the results of species range size conservatism, we can hypothesize that MED species may have expressed their potential range more fully than NWE species, resulting in a more frequent significant phylogenetic signal for the former. This hypothesis is supported by the fact that MED species range sizes are larger than the ones of NWE species in average (Fig. 3).

Over the last decade, the question of phylogenetic conservatism of species range size has been addressed for a variety of clades. However, evidence for species range size conservatism is mixed and for the moment, no consistent conclusion has been reached (e.g. [START_REF] Mouillot | Spatial overlap enhances geographic range size conservatism[END_REF][START_REF] Morin | Niche breadth and range area in North American trees[END_REF]. Here we show that phylogenetic conservatism may differ between contemporaneous species of the same group and that it may be labile through time within a same lineage. The lability of this macroecological trait can explain the conflicting results of previous studies on phylogenetic conservatism of species range size (Table 1). It should be mentioned that only a multi-scale approach can identify this lability. Our conclusions on range size phylogenetic conservatism would have been different if we had focused our analyses on one geographical area and one chronozone only. The instability of the phylogenetic signal through time and space suggests that range size conservatism may be scale-dependent and emerges only for certain given combinations of extrinsic and intrinsic factors. Future studies should thus investigate environmental conditions that may favour species range size conservatism.

Figure 1 Biostratigraphical and palaeogeographical context of the early Pliensbachian. (A) Ammonite chronozones [START_REF] Page | The Lower Jurassic of Europe: its subdivision and correlation[END_REF][START_REF] Gradstein | The Geologic Time Scale[END_REF] and their approximate absolute ages [START_REF] Gradstein | The Geologic Time Scale[END_REF][START_REF] Ogg | A Concise Geologic Time Scale[END_REF]

  . (B) Palaeogeographical reconstruction of the western Tethys and adjacent areas with the palaeolocation of the 104 fossil localities used here. NW European localities are represented by circles and Mediterranean localities are represented by squares. Abbreviations: Ad, Adria bloc; Africa, African bloc; Anatolia, Anatolian bloc; Eurasia, Eurasian bloc; Ib, Iberian bloc.

Figure 2

 2 Figure2Species-level phylogenetic hypothesis for early Pliensbachian ammonites (after[START_REF] Hardy | Deep-time phylogenetic clustering of extinctions in an evolutionarily dynamic clade (Early Jurassic ammonites)[END_REF] together with their province(s) of occurrence. Inter-species phylogenetic distances correspond to branch lengths between each species pair in the phylogeny. Abbreviations: MED, Mediterranean; NWE, North-West European.

Figure 3

 3 Figure 3 Distribution of latitudinal ranges and extent of occurrences for early Pliensbachian ammonites of the western Tethys and adjacent areas. Note the typical strongly right-skewed distribution.

ACKNOWLEDGEMENTS

We are grateful to Michael N Dawson, Luis Valente, Kenneth De Baets and an anonymous reviewer for their constructive comments, which helped us to improve the manuscript. We thank Bruno Vrielynck (Paris) for the reconstruction of the early Pliensbachian palaeogeographic map of the western Tethys, as well as for the calculation of fossil locality palaeocoordinates. Romain Vaucher (Lyon) is thanked for his help with Adobe Illustrator. This study was partly supported by the Fondation pour la Recherche sur la Biodiversité (FRB).

SUPPORTING INFORMATION

Additional Supporting Information may be found in the online version of this article:

Appendix S1 References for Table 1,