Martin Pickford
email: martin.pickford@mnhn.fr

Europe's last anthracothere (Artiodactyla, Mammalia) from Ribolla (MN 12) Italy

Keywords: Anthracotheriidae, Biogeography, Biochronology, Palaeoecology, University of Florence

Anthracotheres are generally considered to have gone extinct in Europe at the end of the early Miocene (summit MN 4 to base MN 5, Burdigalian) whereas they persisted in Africa until the latest Miocene and in India into the Pleistocene. However, in 1910, Stehlin described an anthracothere upper molar in a fragment of maxilla, reported to be from Monte Massi (Casteani) Italy (late Miocene -Turolian) : Anthracotherium (?) meneghinii but its affinities have remained elusive ever since its description, partly due to the fact that the specimen is poorly preserved and the only tooth is deeply worn. The fossil has been described as being somewhat larger than Microbunodon. Herein, an additional fossil anthracothere fossil is described from the lignites of Ribolla, Italy. It comprises a left mandible fragment with well-preserved m/3 and the roots of m/2. It represents a hitherto unknown genus and species of anthracothere, probably related to Microbunodon, and proves the presence of this family of mammals in Europe at the end of the Miocene (Turolian, MN 12).

Introduction

A widespread view in European mammalian palaeontology is that the family Anthracotheriidae went extinct in the continent at the end of the early Miocene (Burdigalian) [START_REF] Antunes | The last Anthracothere Brachyodus onoideus (Mammalia, Artiodactyla) from westernmost Europe and its extinction[END_REF] although [START_REF] Van Der Made | Superfamily Hippopotamoidea[END_REF] postulated that Anthracotherium? persisted into the late Miocene in Tuscany as part of an island fauna (Hürzeler, 1982). The family is well represented in the Eocene and Oligocene deposits of Europe [START_REF] Stehlin | Zur revision der Europäischen Anthracotherien[END_REF] but the disappearance of Brachyodus at the end of MN 4 has long been considered to be of biostratigraphic importance, the teeth of the genus being easily recognised on account of their dimensions and the presence of wrinkled enamel. The family persisted in Asia until the Pleistocene (Merycopotamus [START_REF] Falconer | Note on the fossil Hippopotamus of the Siwalik Hills[END_REF] and in Africa until the latest Miocene (Libycosaurus, [START_REF] Bonarelli | Dinosauro fossile del Sahara Cirenaico[END_REF].

In the Sezione di Geologia e Paleontologia., Museo di Storia Naturale, Universita di Firenze, previously known as the Istituto de Geologia de Firenze (IGF) there is a mandible of a small anthracothere with bunodont dentition from Ribolla (Figs 23). The m/3 in the mandible is wellpreserved and is only lightly worn, and it confirms the presence of an anthracothere in the late Miocene of Europe.

The aim of this paper is to describe and interpret the systematic position, palaeoecology and palaeobiogeography of the small anthracothere mandible from Ribolla.

Locality, Geological context and Age

The fossil described herein was collected from the Lignite picea (good quality lignite) in the Ribolla Mine (labels with the specimen) (Fig. 1,2). Ribolla was one of a series of lignite mines in Tuscany, others being Baccinello, Montebamboli and Casteani (Benvenuti et al. 1999a[START_REF] Benvenuti | Sedimentary facies analysis in paleoclimatic reconstructions. Examples from the Upper Miocene-Pliocene of south-central Tuscany (Italy)[END_REF][START_REF] Benvenuti | Mammal biochronology, UBSU and paleoenvironment evolution in a post-collisional basin: evidence from the Late Miocene Baccinello-Cinigiano Basin, Southern Tuscany, Italy[END_REF][START_REF] Benvenuti | Messinian-Earliest Zanclean tectonic-depositional dynamics of the Cinigiano-Baccinello and Velona Basins (Tuscany, Italy)[END_REF][START_REF] Rook | Geochronology of Oreopithecus-bearing succession at Baccinello (Italy) and the extinction pattern of European Miocene hominoids[END_REF][START_REF] Rook | Magnetostratigraphy of the Late Miocene Baccinello-Cinigiano Basin (Tuscany, Italy) and the age of Oreopithecus bambolii faunal assemblages[END_REF][START_REF] Rook | Geopalaeontological setting, chronology and palaeoenvironmental evolution of the Baccinello-Cinigiano Basin continental successions (Late Miocene, Italy)[END_REF]. The exact level from which the fossil was collected is not known, but the preservation of the specimen indicates that it was preserved in lignite. The lignites in the Baccinello-Cinigiano Basin have been correlated to the late Miocene on faunal grounds, and they occur within a thick pile of sedimentary deposits that, according to palaeomagnetic stratigraphy, span the period +8.1 Ma (base of V1 level) to 6.4 Ma (top of V3 level) [START_REF] Rook | Magnetostratigraphy of the Late Miocene Baccinello-Cinigiano Basin (Tuscany, Italy) and the age of Oreopithecus bambolii faunal assemblages[END_REF]. Levels V1 and V2 yielded the enigmatic ape-like Oreopithecus bambolii, whereas by the onset of the V3 level at 6.7 Ma, this hominoid is considered to have gone extinct. According to one of the referees, there is a possibility that the anthracothere fossil was not from Ribolla, but from another occurrence of lignite, possibly of Oligocene age. For the purposes of this paper we accept that the labels accompanying the fossil accurately record its provenience.

The fauna from Ribolla has been discussed by several authors [START_REF] Merciai | Sopra alcuni resti di vertebrati miocenici delle ligniti di Ribolla[END_REF][START_REF] Campana | Considerazioni sulle Antilopi terziare della Toscana[END_REF]Hürzeler, 1982;Kotsakis, 1984a;[START_REF] Gentili | The Italian fossil primate record : Recent finds and their geological context[END_REF][START_REF] Abbazzi | New data on the vertebrate assemblage of Fiume Santo (North-west Sardinia, Italy), and overview on the late Miocene Tusco-Sardinian palaeobioprovince[END_REF]) and the general opinon is that the deposits that yielded the fossils are of late Miocene age (Turolian, MN 12).

Material and Methods

I am indebted to E. Cioppi (Universita di Firenze) for the following information about the fossil anthracothere from Ribolla and for images of the labels and the original fossil.

The specimen is curated at the University of Firenze under catalogue number IGF 3988 (IGF is an abbreviation of « R. Istituto Geologico Firenze », and is still used for the catalogue of specimens, even though the name of the institute has changed to Sezione di Geologia e Paleontologia. Il Museo di Storia Naturale)

The specimen is a fragment of mandible containing a complete m/3 and a fragmentary m/2. Labels with the fossil indicate that it was collected from the lignite mine at Ribolla which was active from 1870 until 1954, when the mine was closed following a disaster. At this mine, lignite picea (good quality lignite) was extracted.

Two of the labels with the specimen are old, there is no year written on them, but « N° 3988 » is an old number in the catalogue, suggesting that the entry was made sometime during the years 1870-1880 (Fig. 2). One label attributes the fossil to Sus cherodes (sic) Pomel, and has « Miocene, Ligniti di Ribolla » written on it. The second label identifies the specimen as "Suide ind. Miocene. Ligniti di Ribolla". Alterations to the second label comprise two corrections concerning its identification: the first is in pencil "Listriodon n.sp." in the handwriting of Dr A. Azzaroli. There is a line scored through the names, correcting both to "Anthracotheride. Hü." (evidently J. Hürzeler). A third label mentions IGF 3988 and M 173 (= mould 173).

Images of the original fossil and the cast have been prepared. Diagnosis :-Small anthracothere with relatively bunodont dentition; in m/3 no junction between the preentocristid and prehypocristid; distal opening of the valley between the hypoconid and entoconid narrow, slit-like; slightly subdivided hypoconulid; hypoconulid located in mid-line of the tooth; lightly wrinkled enamel Species Etruscotherium ribollaense nov.

Diagnosis :-As for genus, m/3 +/-27 mm long.

Derivatio nominis :-Etruscotherium combines the root Etrusco (for the ancient Etruscan civilization of Central Italy) and therium -Greek for beast. The species name is for Ribolla, the type locality.

Type specimen :-IGF 3988, left mandible fragment with roots of m/2 and complete m/3. Age :-Turolian : MN 12 (Kotsakis, 1984a(Kotsakis, , 1984b)), between 8.1 and 6.4 Ma [START_REF] Rook | Magnetostratigraphy of the Late Miocene Baccinello-Cinigiano Basin (Tuscany, Italy) and the age of Oreopithecus bambolii faunal assemblages[END_REF].

Description

The left mandible from Ribolla (IGF 3988) contains the roots of m/2 and a complete, lightly worn m/3 (Figs 234). There is a long retromolar space, the mandible is slightly broader than the molars, but the base of the jaw is missing so its depth cannot be measured. The m/2 was about 12 mm broad at the posterior lophid and the length would have been ca 18 mm (estimated from the broken roots). The m/3 is 27.0 mm long, 14.0 mm broad at the first lophid, 13.2 mm at the second lophid and 9 mm at the third lophid.

The crown of the m/3 is comprised of three lophids, the mesial and central ones each with two cusps, and the third with a single centrally positioned cusp. The mesial lophid (protoconid and metaconid) is slightly broader than the second lophid (hypoconid and entoconid) which, in its turn, is much broader than the third lophid (hypoconulid). There is a mesial cingulid (partly broken away). The enamel of the tooth is lightly wrinkled.

The protoconid has two prominent crests (preprotocristid and postprotocristid) both of which descend from the apex of the cusp towards the midline of the tooth. The metaconid likewise has two crests which lead towards the midline, the premetacristid stopping short of the preprotocristid, and the postmetacristid coalescing with the postprotocristid to wall off the rear of the trigonid basin. In addition to these main crests, the protoconid has a subtle posterior crest that descends vertically towards a small remnant of buccal cingulum in the anterior transverse valley, while the metaconid has a mesiolingual cristid that descends towards a small stylid at the mesio-lingual corner of the tooth, and a distolingual cristid that descends towards the lingual end of the anterior transverse valley, terminating close to a tiny pimple of enamel at the end of the valley. In distal view, the posterior part of the mesial lophid shows a pattern of four crests analogous to the M-structure that characterises tragulid lower molars (Fig. 4). The hypoconid has three crests, a prehypocristid that descends mesiolingually towards the centre-line of the tooth, forming a prominent wall in the middle of the anterior transverse valley. The posthypocristid descends into the middle of the posterior transverse valley where it coalesces with a cristid emanating from the hypoconulid, thereby forming a wall in the centre of the posterior transverse valley. Finally the hypoconid has a third swollen cristid that descends into the talonid basin, almost subdividing it into two. The entoconid has three cristids. The mesiolingual entocristid runs mesially ending close to the postmetacristid, but without joining it. The distolingual entocristid is directed steeply distally, but does not block the posterior transverse valley. The preentocristid, which is swollen, extends mesio-buccally towards the anterior transverse valley. The hypoconulid is centrally positioned and has a weak subdivision at its apex, expressed as a narrow groove on its mesial and distal surfaces. From the buccal half of the hypoconulid, there is a swollen cristid (prehypocristulid) leading mesio-lingually, subdividing the posterior transverse valley into two halves. The same buccal part of the hypoconulid has a low cristid that extends from its apex along the buccal side of the crown terminating at the base of the hypoconid. The lingual part of the hypoconulid forms a crest (posthypocristulid) which extends to the base of the entoconid.

In side view, the apices of the protoconid, hypoconid and hypoconulid are observed to be at the same height. The tooth is thus bunodont, but with slight selenodont and cristodont tendencies.

Discussion

The morphology and dimensions of the m/3 in the Ribolla mandible show some resemblances to specimens of Microbunodon [START_REF] Depéret | L'histoire géologique et la phylogénie des Anthracotheridés[END_REF] from Pakistan, notably Microbunodon milaensis, but there are significant differences (Fig. 5,6, Table 1). The bunodont morphology of the tooth from Ribolla is radically different from the selenodont molars of Merycopotamus and Libycosaurus (Fig. 5). [START_REF] Lihoreau | Description and palaeobiology of a new species of Libycosaurus (Cetartiodactyla, Anthracotheriidae) from the Late Miocene of Toros-Menalla, northern Chad[END_REF]. For ease of comparison, the images have been brought to the same length. Note the relatively short precristids and postcristids on the protoconids and hypoconids of Etruscotherium (A) and Microbunodon (B, C) which terminate close to the midline of the crown, contrasting with the elongated cristids in Merycopotamus (D, E) and Libycosaurus (F) which extend well towards to the lingual margin of the crown. [START_REF] Lihoreau | A new species of the genus Microbunodon (Anthracotheriidae, Artiodactyla) from the Miocene of Pakistan: genus revision, phylogenetic relationships and palaeobiogeography[END_REF] described the lower molars of Microbunodon milaensis in the following terms :-« Junction between preentocristid and prehypocristid. Distally open longitudinal valley between hypoconid and entoconid. Looplike hypoconulid on m/3, centred on longitudinal axis of tooth and mesiodistally expanded. No entoconulid ». The Ribolla tooth has no junction between the preentoctistid and the prehypocristid, the two crests being separated by a narrow groove and the hypoconulid is not mesio-distally expanded but is appreciably shorter than the second lophid. Similarities to, and differences from, Microbunodon milaensis are listed in Table 1. Comparison of the Ribolla fossil with the Briatexte (Tarn, France) mandible described by [START_REF] Astre | Le Brachyodus porcinus de Briatexte et les caractères de la mandibule des petits Brachyodus oligocènes[END_REF] as Brachyodus porcinus, reveals some differences. Among them the hypoconulid is distinctly subdivided into two parts by a deep, obliquely oriented mesio-distal groove (which produces a selenelike hypoconulid) [START_REF] Pickford | Observations on Anthracotheriidae (Mammalia : Artiodactyla) from Napak, early Miocene, Uganda[END_REF], whereas in Etruscotherium, the groove is shallow and narrow.

The fossils from St Henri, France, attributed to Brachyodus borbonicus by [START_REF] Geais | Le Brachyodus borbonicus des Argiles de St-Henri (près Marseille)[END_REF] but more likely representing a Bothriodon, show the prehypocristid crossing the crown almost to the lingual margin of the tooth, much as in Sivameryx, Merycopotamus and Libycosaurus (Fig. 5) The teeth of this species are thus appreciably more selenodont than those of Etruscotherium.

There are some similarities between the m/3s of Etruscotherium and Myaingtherium Tsubamoto et al. 2011, from the Eocene Pondaung Formation of Myanmar, but the hypoconulid in the latter genus is clearly subdivided into two parts (buccal cusp of hypoconulid and entoconulid), unlike the narrow, shallow groove that subdivides the hypoconulid of Etruscotherium. In addition, the M-structure on the distal face of the first lophid (distobuccal protocristid and distolingual metacristid) is more clearly expressed in Myaingtherium. One can postulate rather similar diets for Myaingtherium kenyapotamoides and Etruscotherium ribollaense. In 1910, Stehlin described a maxilla fragment with a worn and damaged upper second molar from the Miocene lignite of Grosseto (Monte Massi) housed in the Museum in Pisa, Italy (Fig. 7) (the current whereabouts of the fossil are not known). He called it Anthracotherium (?) meneghinii and remarked that it was a complete anachronism, an allusion to the commonly held view that anthracotheres went extinct in Europe during the early Miocene. This fossil had previously been mentioned by Forsyth Major (1872) who thought the maxilla might represent a juvenile individual with a deciduous tooth. [START_REF] Hurzeler | Oreopithecus bambolii Gervais. A preliminary report[END_REF][START_REF] Hurzeler | L'âge géologique et les rapports géographiques de la faune de mammifères du lignite de Grosseto (Note préliminaire)[END_REF] considered that the fossil came from a greenish silty-sand deposit beneath the lignites, rather than from the lignite. The history of study of this fossil was summarised by Kotsakis (1984a) who concluded that it was unlikely to have been collected from Casteani. Until further research is done, the provenience of this fossil will remain in doubt. Given the uncertainty about the affinities and provenience of the holotype of Anthracotherium (?) meneghinii allied to doubts concerning the meristic position of the tooth that it contains, it is recommended that the name should apply only to the type specimen (i.e. it is a nomen vanum). Kotsakis (1984aKotsakis ( , 1984b) ) suggested that, if the maxilla described by [START_REF] Stehlin | Zur revision der Europäischen Anthracotherien[END_REF] really did come from Miocene deposits then its affinities might lie with Merycopotamus in the sense of the North African records of this genus [START_REF] Black | A new species of Merycopotamus (Artiodactyla: Anthracotheriidae) from the late Miocene of Tunisia[END_REF][START_REF] Black | Anthracotheriidae[END_REF] which are today recognised as being distinct from the Indian members of the genus, the Libyan, Chadian, Tunisian, Algerian and Ugandan material being attributed to Libycosaurus [START_REF] Bonarelli | Dinosauro fossile del Sahara Cirenaico[END_REF](Pickford, 1991a, 1991b[START_REF] Pickford | The anterior dentition of Libycosaurus anisae and Kenyapotamus coryndoni from Beglia, Tunisia: implications for the affinities of anthracotheres and hippopotamids Notes du Service Géologique de Tunisie[END_REF][START_REF] Pickford | Sexual and individual morphometric variation in Libycosaurus (Mammalia, Anthracotheriidae) from the Maghreb and Libya[END_REF][START_REF] Lihoreau | Description and palaeobiology of a new species of Libycosaurus (Cetartiodactyla, Anthracotheriidae) from the Late Miocene of Toros-Menalla, northern Chad[END_REF]. The hyothesis of a relationship between Anthracotherium (?) meneghinii and Libycosaurus can be discarded because the latter genus has much more selenodont, quadricuspidate molars and is considerably larger. -Pacego & Dantin Cereceda (1915) published detailed descriptions of teeth, jaws and postcranial elements of Listriodon splendens from Cerro del Ortero, Spain, attributing the fossils to the large subspecies major. The authors also discussed and illustrated what they considered to be an unknown artiodactyl. H.G. Stehlin (in Hernandez-Paceogo & Dantin Cereceda, 1915) in a written communication to the authors commented that, after examining casts of the latter specimens, he considered that they showed affinities to Hyopotamus and more particularly to a specimen from Monte Massi, Italy, that he had identified as Anthracotherium? Meneghinii (sic) but probably representing a new genus of anthracothere. In fact all the Spanish fossils concerned are juveniles of Listriodon splendens major and are not in any way related to anthracotheres.

Hernandez

Comparisons between Etruscotherium ribollaense and the bunodont tragulid Dorcabune anthracotherioides Pilgrim, 1910 (Fig. 8), reveals some similarities such as the bunodont morphology of the crown and the presence of wrinkled enamel but in detail there are several important differences, so attribution of the Ribolla specimen to Tragulidae can be discounted. However, it is possible that the ecology of Etruscotherium could have been rather similar to that of Dorcabune, the similarites in dental morphology being an expression of convergent evolution due to selection in two distantly related taxa which have similar diets (in this case probably dominantly frugivorous, but with omnivorous tendencies and some folivory).

Conclusions

A mandible with m/3 from Ribolla, Italy (MN 12, Turolian) is attributed to a new genus and species of anthracothere, Etruscotherium ribollaense. Its closest relative is Microbunodon, but the differences from this genus are sufficient to warrant creation of a new genus to accomodate it. This is the last documented record of anthracotheres from Europe.

It was previously widely accepted that anthracotheres went extinct in Europe at the end of MN 4 [START_REF] Antunes | The last Anthracothere Brachyodus onoideus (Mammalia, Artiodactyla) from westernmost Europe and its extinction[END_REF] and none has been reliably recorded from the middle Miocene and most of the late Miocene. Apart from the doubfully provenienced holotype of Anthracotherium? meneghinii, the Ribolla specimen is the only anthracothere known from the late Miocene of Europe, which suggests that after going extinct in the continent at the end of MN 4, a separate lineage of anthracotheres managed to disperse back to Europe during the late middle Miocene or early late Miocene (broadly Turolian according to Kotsakis (1984aKotsakis ( , 1984b)). The latter author hinted at relations with North African anthracotheres which survived into the Late Miocene, but in fact the Ribolla specimen reveals closer affinities with Microbunodon from the Indian Subcontinent than with Libycosaurus from Libya and Tunisia, suggesting a dispersal from Asia to Europe, rather than from Africa to Europe.

Figure 1 .

 1 Figure 1. Location of Ribolla, Italy (Turolian, MN 12).

Figure 2 .

 2 Figure 2. Labels associated with the holotype of Etruscotherium ribollaense, gen. et sp. nov. The lower and middle labels in black ink date from the late 1800's, the lower one with additions in pencil by A. Azzaroli and in blue ink by J. Hürzeler. The top label refers to the mould from which cast was made. A) buccal, B) occlusal, and C) lingual views of original fossil (images courtesy E. Cioppi).

Figure 3 .

 3 Figure 3. IGF 3988, cast of mandible of Etruscotherium ribollaense from Ribolla, Italy (MN 12). A) stereo occlusal views, B) buccal view, C) lingual view (scale : 10 mm).

Figure 4 .

 4 Figure 4. Oblique distal stereo view of a cast of the left m/3 of Etruscotherium ribollaense. The arrow points to the M-structure on the distal face of the mesial lophid. Note the slit-like distal opening of the basin between the hypoconid and entoconid (second lophid) and the slight subdivision of the hypoconulid (note the wrinkled enamel) (scale at hypoconulid : 10 mm).

Figure 5 .

 5 Figure 5. Morphology of right m/3s of Mio-Pliocene anthracotheres. A) Etruscotherium ribollaense (left m/3 reversed), B) Microbunodon milaensis (image modified from Lihoreau et al. 2004), C) Microbunodon silistrensis (image modified from Lihoreau (2003), D) Merycopotamus pusillus (image modified from Lihoreau, 2003), E) Merycopotamus dissimilis (image modified from Tsubamoto et al. 2012), F) Libycosaurus garhi (image modifed from Lihoreau et al. 2014). For ease of comparison, the images have been brought to the same length. Note the relatively short precristids and postcristids on the protoconids and hypoconids of Etruscotherium (A) and Microbunodon (B, C) which terminate close to the midline of the crown, contrasting with the elongated cristids in Merycopotamus (D, E) and Libycosaurus (F) which extend well towards to the lingual margin of the crown.

Figure 6 .

 6 Figure 6. Bivariate (length-breadth) plots of m/3s of small anthracotheres, Microbunodon minimus(Cuvier, 1822) from Europe (+), Microbunodon silistrensis[START_REF] Pentland | Description of fossil remains of some animals from the North-East Border of Bengal[END_REF] from the Indian Subcontinent (O), Microbunodon milaensis[START_REF] Lihoreau | A new species of the genus Microbunodon (Anthracotheriidae, Artiodactyla) from the Miocene of Pakistan: genus revision, phylogenetic relationships and palaeobiogeography[END_REF]) from Pakistan (star), and Etruscotherium ribollaense from Italy (R) (Data for Microbunodon is from[START_REF] Lihoreau | A new species of the genus Microbunodon (Anthracotheriidae, Artiodactyla) from the Miocene of Pakistan: genus revision, phylogenetic relationships and palaeobiogeography[END_REF]; that for Myaingtherium (x) is from[START_REF] Tsubamoto | A new anthracotheriid artiodactyl from the Eocene Pondaung Formation of Myanmar[END_REF]).

Figure 7 .

 7 Figure 7. Sketch of the holotype right maxilla fragment of Anthracotherium(?) meneghinii Stehlin (1910) from Monte Massi (Casteani), Italy. Occlusal view of tooth interpreted to be the M2/ with the reconstructed occlusal outline of M1/ and mesial alveolus of M3/. Drawing by Dr Fucini (not to scale).

Figure 8 .

 8 Figure 8. Left m/3 of Dorcabune anthracotherioides from the Siwaliks of India, specimen curated in the Wadia Institute of Himalayan Geology, Dehra Dun, India. A) buccal view, B) stereo occlusal view, C) lingual view (scale : 10 mm).

Table 1 .

 1 Comparison of morphology of the m/3s of Microbunodon milaensis and Etruscotherium ribollaense.

	Character	Microbunodon milaensis	Etruscotherium ribollaense
	Junction between preentocristid and	Yes	No
	prehypocristid
	Distally opened longitudical valley between	Yes	Yes, but slit-like
	hypoconid and entoconid
	Loop-like hypoconulid on m/3	Yes	No, subdivided
	Hypoconulid centred on longitudinal axis of tooth	Yes	Yes
	Hypoconulid mesio-distally expanded	Yes	No, short

Acknowledgements

The cast of the Ribolla anthracothere was provided by the late L. Ginsburg. The tragulid specimen in the Wadia Institute of Himalayan Geology was made available by B.N Tiwari and R. Sehgal. Thanks to L. Rook, E. Cioppi (Museo di Storia Naturale -Sistema Museale d'Ateneo, Università degli Studi di Firenze) and C. Sorbini (Paleontologia, Museo di Storia Naturale, Università di Pisa) for curatorial information about fossils in their care.


Linking 4.0 Technologies and performance indicators based on a reference Model for supply chain

Keywords: Industry 4.0, Technologies 4.0, Supply chain Model, Performance Indicator, Supply chain 4.0, Automobile industry

Agadir -Morocco "New advances and challenges for sustainable and smart industries"

INTRODUCTION

The last decade has seen the emergence of the notions of corporate network, supply chain and extended enterprise. These notions highlight that any product is the result of group companies work, organized in more or less structured networks. The mastery of global logistics is a complex and transversal phenomenon [START_REF] Morana | De la logistique globale (Supply Chain Management) à la logistique durable (Sustainable Supply Chain Management) : de l'importance de l'économique, de l'environnemental et du social/sociétal dans les chaînes logistiques actuelles[END_REF]. Complex in the sense that the supply chain can be extended and involves multiple and varied partners (public authorities, industrialists, distributors, assemblers, etc.). The speed of traffic and the tension of flows is constantly increasing and the constraints to be respected, both contractual and regulatory, are becoming numerous [START_REF] Baglin | Management industriel et logistique : concevoir et piloter la supply chain[END_REF]).

To manage their supply chain, companies seek to manage their activities in an optimal way by playing both on the organization of their productive process on a global scale and on their information system allowing them to steer this organization. To meet this challenge, the logistics processes in companies in all industries must of course be digitized and optimised accordingly. Companies that operate in international markets, such as the automotive industry, and have a large customer base, in particular, must make heavy decisions and digitalise their internal and external logistics and more broadly their global supply chain in order to improve the flow of information and not threaten their sales.

The basics of digital logistics are processes and objects that can be controlled, organized and qualified as smart (intelligent). In this context, we are also talking about intelligent logistics or 4.0 logistics. GPS, RFID, cloud computing architectures, computerized data interchange (EDI), large data, telematics and many others are used. A functional intralogistics system is the key to efficient production in Industry 4.0.

Beyond the production aspect described above, logistics 4.0 supports the performance of the global supply chain. It allows the networking and nesting of processes, objects, supply chain partners and customers through information and communication technologies with decentralized decision-making structures to increase effectiveness and efficiency However, companies need to be guided to the most relevant technologies to use to drive their logistics. In order to ensure a better management organization for a global management of the global supply chain this work proposes an original methodology allowing companies to choose the best technologies from industry 4.0 to drive their supply chains. The originality of the proposed approach consists in starting from the decisions necessary for the management of the logistics. Then it deduces the objectives and the means of actions to manage it and finally select the most relevant technologies to make the system of indicators, reliable, available and manage from the strategic level to the realtime indicators. The originality of the proposed methodology is also to select steering decisions in a reference model that will also be explained in this paper. The technologies of industry 4.0 will be selected on the basis of the benchmarking indicators related to these Y. EL KIHEL A. AMRANI and Y. DUCQ Univ.Bordeaux, Laboratory IMS, France yousra.el-kihel@ubordeaux.fr, aicha. zouggar-amrani @u-bordeaux. yves.ducq@ubordeaux.fr '20 -November 12-14, 2020 -Agadir -Morocco decisions, which will also be given in this article. Thus, section 2 proposes a state of the art of the reference models for supply chains and technologies of Industry 4.0. The proposed methodology will be presented in a second step, as well as the proposed reference model for supply chain management and the selected technologies. Finally, the most relevant technologies for each step of the indicator life cycle, the reference model of monitoring indicators to measure the performance of the supply chain and the technologies of Industry 4.0 most relevant to support each group of indicators in its reliability, availability and updating will be presented.

MOSIM

LITERATURE REVIEW

Methodology and reference models for supply chains

According to the literature review [START_REF] Ducq | Evaluation de la performance d'entreprise par les modèles -Habilitation to Supervise Research -University of Bordeaux[END_REF], there are several methods that allow to measure the performance of large industrial enterprises, and several works have been done on the modelling of the supply chain. Among these models one can mention the most famous in logistics: the SCOR model (Apics 2017), the reference model EVALOG ( 2004), the logistic guide ASLOG (2006), and the VRM (Value Chain Group, 2007).

The table 1 below presents our comparative study of the supply chain management reference models.

Table 1. Comparison of SCM reference models

This study shows that all of these models propose a process models and indicators, but excepted GRAI, none of them present a decisional reference model.

Technologies in Industry 4.0

The "Industry 4.0" concept was built on digital technologies to make manufacturing more flexible, agile and more responsive to customer needs. The real-time acquisition of data, the ability to process them with advanced means and the use of internet and sensors make the factory better controlled. Today it is possible to create a smart factory where the Internet, wireless sensors, software and other advanced technologies are used to optimize production in cost and quality and improve customer satisfaction. According to [START_REF] Moeuf | Identification des risques, opportunités et facteurs critiques de succés de l'industrie 4.0 pour la performance industrielle des PME[END_REF]) Industry 4.0 is an industrial management concept aimed at real-time synchronization of different flows and customized product production.

According to (Mayer, 2017) the industry of the future refers to factories connected, made flexible and intelligent through the networking of machines, products and people. Several technologies have been identified in the literature.

The integration of different digital technologies in the industry offers many advantages especially when they are connected. These tools (table 2) enable the company to respond more quickly to market fluctuations, to offer more customized products and to increase its operational efficiency as part of a continuous improvement cycle.

They are also very effective in supporting decisionmaking (Dombrowski et al.2017).

Table 2. Technologies 4.0 commonly admitted in literature (Mayer 2018)

In the literature, numerous techniques and methods are cited for deploying digital transformation and improving performance towards a 4.0 enterprise. The choice of these techniques and methods depends in particular on the strategic orientations, the stakes, the internal and external contexts and the available resources, both human and technological. Although in (Hermann et MOSIM'20 -November 12-14, 2020-Agadir -Morocco al.2015) The first vocation of 4.0 technologies will be to support the process of updating indicators in order to provide them as close as possible to decision makers and to make them reliable and displayed correctly. An analysis of the life cycle of a performance indicator was conducted to consistently support each of its development phases. The proposed contributions of Technologies 4.0 to the different phase of PI life cycle are detailed in the section 4.

METHODOLOGY

The global PERFLOG Method

In parallel with the development of new forms of management, we have witnessed the emergence of new, more flexible Industry 4.0 technologies that are changing production methods and the operating rules of logistics systems. It is currently difficult for companies to choose which technologies are best suited to their management methods and generally to their needs.

The stated objective of the methodology proposed in our research work is to allow companies to choose in coherence the control and monitoring modes (decision and indicators) and technologies of the 4.0 industry in order to set up a real logistics 4.0. These modes of control and monitoring must be based on process models, some of which have been described in the previous section, but also on decision-making models.

The PERFLOG methodology proposed in Figure 1 achieves the objectives presented above. In a first step it proposes the decisional modeling of the supply chain design by proposing a reference model of SC design decisions. This reference model will not be presented in this article. In a second phase, PERFLOG proposes the modelling of the operating decisions of the supply chain, based on a second reference model that will be slightly presented below. The third, fourth and fifth steps are

Global Supply Chain decision modeling

Global supply chain decision modeling is a complex task because it requires mastery of the chain's components and modeling to optimize processes and reduce the logistics costs associated with production, storage and distribution.

To do so, this work wants to design a grid adapted to this perimeter which is more and more requested by the companies in order to better control the flows of their supply chain. Modeling is an essential step to understand, analyze and master the process of the entire supply chain. In this phase, we propose decisional reference models.

The originality is that companies can use these reference models to design and manage the supply chain. They are not obliged to select all the decisions proposed in the model but must at the end ensure the coherence between all the selected ones in order to have a real decision system and not only disparate decisions.

Two reference models (for SC design and SC operations) were therefore defined in this research work. These reference models are based on the GRAI model and in particular the GRAI grid.

The first GRAI grid of reference developed, GRAILOG-Cop, is a grid for the control of the SC design (how to control the design of the network of partners in a supply chain up to its implemented operation. In order to enrich the existing GRAI model the existing process models (as SCOR) were considered in order to achieve a better exhaustiveness in the functions (Summary Table 2). Therefore, it is important to converge towards design decisions in a supply chain, this is the usefulness of the Grailog-cop proposal.

The second reference model, GRAILOG-Exp, means Grailog Exploitation (operation) aims in step 2 to build the supply chain operations control.

MOSIM '20 -November 12-14, 2020 -Agadir -Morocco This work intends to disconnect the design from the operation even if both must be coherent. This is why the first grid must be elaborated before the second one. Both reference models are intended to be modular, linking two phases. In the GRAILOG-Exp grid, the selected monitoring functions are also inspired from the SCOR model, which is essential in a supply chain because it allows visualization by key process: PLAN, SOURCE, MAKE, DELIVER, and RETURN and other added columns expressing the "vital functions" of monitoring a company or a network of companies: Manage sales, industrialization, and "more recent functions": Manage sustainable development and social responsibility and Manage crisis/risks. All the functions of the GRAILOG-Exp model are justified and referenced in the literature by standards such as RSE, ASLOG... and standards such as ISO 9001, ISO 26000 in order to have a global management of the supply chain.

Without going into the details, the table 3, presenting the Grailog grid of KPI's, shows the list of functions selected in the GRAILOG-Exp reference model.

Identification of performance indicators

The identification of performance indicators in the PERFLOG method is based on the ECOGRAI method [START_REF] Ducq | Definition and aggregation of a Performance Measurement System in three aeronautical workshops using the ECOGRAI Method[END_REF]) which proposes to define the indicators based on the objectives and decision variables relating to each decision. The identification of indicators is therefore divided into three phases.

Thus, the third phase of our methodology, consists in identifying the objectives for the global Supply Chain and then supply chain decisions. Based on the models studied, a set of main objectives is proposed by decision for each of the two grids GRAILOG-Cop and GRAILOG-Exp. The selected objectives come from a bibliographical research (SCOR, Value Reference Model [START_REF] Mohammadi | Comparison of supply chain process models based on serviceoriented architecture[END_REF] which showed a preponderance of certain objectives compared to others. Thus, 6 performance areas were selected: Reliability, responsiveness, cost, quality, innovation, environmental and social aspect. Then, in the fourth phase, decision variables are identified that represent the variables on which decision-makers act to make the system evolve so that it can achieve its objectives.

Identification of performance indicators (PI Grid)

In the fifth phase, decision makers need to identify their performance indicators that will be consistent with their objectives and decision variables. To help them in this direction, the PERFLOG method proposes a KPI's grid for each proposed function of the exploitation grid (Table 3). The indicators chosen are based on three performance measurement frameworks: SCOR, ASLOG, and BSC. This KPI grid gives generic indicators for each function that appear to be important in any type of industrial sector. Of course, this grid is not exhaustive and other indicators can be proposed.

THE CONTRIBUTION OF INDUSTRY 4.0 TO PERFORMANCE INDICATORS

Industry 4.0 technologies at the service of performance indicators and supply chain management:

The first five steps of the PERFLOG methodology make possible to identify a number of relevant indicators. However, performance indicators must, on the one hand, be SMART (Simple, Measurable, Accessible, Realistic and Time-bound) and must therefore updated where and when necessary for decision. For this reason, some technologies in Industry 4.0 can help in this direction, and the rest of this work proposes to list the main technologies useful for indicators for each step of their life cycle and to target more precisely which technique can be used for which group of indicators.

PI Life Cycle and Technologies 4.0

The first analysis starts by observing the different phases of obtaining a performance indicator. In order to make it more reliable and SMART, all phases of what could be called an "PI lifecycle" must be properly powered and supported by 4.0 technologies.

As shown in Figure 2, the obtaining of an indicator must begin with the acquisition of the required data. The "data acquisition or ETL" is the phase 1of the birth of an IP, then follows the phase of "data storage or datawarehouse" then the phase of "calculation" and the final phase which is the display of indicator useful for the decision-maker. The technologies identified in the previous paragraph form the basis of our cross-analysis. The Figure 2 Often, ETL (Extract Transform Load) tools are used but in a very traditional way. Big data is interesting in this phase to process all the required data. Given the importance of the data flow, it can be assigned to most phases of the acquisition, calculation and restitution life cycle. Data Storage is only a repository and data cleaning for which big data processing is not necessary. For the MOSIM'20 -November 12-14, 2020 -Agadir -Morocco digital twin, data is injected into a simulation and a virtual representation, which is made to evolve as its ages. This allows for interesting data capture and visual restitution to be considered in two phases: "acquisition data" and "KPI display". The Iot connects an ever-growing number of systems, devices, sensors, and people through both lowpower extended wireless networks and high-capacity wired networks. It makes it possible to improve the data collection system, in particular via the RFID, RTLS, and its help is crucial in the data acquisition phase. Cloud computing naturally falls into the category of data acquisition but mainly data storage, as it includes costeffective data processing and storage solutions. The growth of connected objects in production, mobile devices and the cloud requires a company to develop it security management (Cyber security) associated with data storage to ensure that data that are stored and transiting over the network are not vulnerable to cyber-attacks. In the KPI calculation the chosen technologies allow to do the calculation like simulation and machine learning / artificial intelligence. These techniques are interesting to support the concatenation of indicators. Machine Learning techniques make it possible to fully exploit the potential of Big Data in the calculation of performance. For the KPI display, are retained the technologies of display and communication that allow to visualize the instantaneous performance, in time in trend..., like the virtual reality, or the digital twin. They add visual information to reality in order to facilitate maintenance, assembly, equipment control, product design, etc. The technologies analysed and considered interesting were selected for implementation and management assistance. Each decision-maker will be able to judge the criticality of one of the phases and implement the appropriate 4.0 technologies. One can also consider that some technologies prove to be interesting at several phases of the life cycle (such as digital twin and cloud computing) but also that some technologies are useless for PI implementation and usage such as 3D printing which does not interfere in any of the phases of the PI life cycle.

Results and first application on PSA

The following grid (Table 3) reflects the functions and decision levels of the GRAILOG-Exp grid explained above. Decisions are not given but reference performance indicators are proposed for each function at each decision level. These performance indicators are necessary for decision-making by function throughout the SC. The objective here is to show the contribution of each technology to the identified PI's. This analysis is complementary to the previous analysis concerning the link between technologies and the life cycle of each indicator. A colour code is used to observe the contribution of each 4.0 technology in the implementation and usage of the indicators.

This work shows that all these techniques can be very useful for performance evaluation and can therefore help the company that wants to efficiently manage its supply chain to know which indicators would be the most relevant and which technologies can accompany these indicators.

The model has been applied in an automotive company of the PSA Morocco group. The PSA Group, with a more than 200 years as a history in the automotive world through its 3 brands "Peugeot, Citroën and DS", is the 2 nd European automobile manufacturer operating worldwide. The PSA plant in Kenitra is an automotive production site located at the Atlantic Free Zone. The site has 3000 employees and produces the Peugeot 208. Its production capacity is 200,000 vehicules by year, with an integration rate of 60%. After analyzing the production process and the different activities of supply chain with production and logistics managers.About twenty interviews took place with these managers at the rate of one hour by interview, we identified on the basis of the reference models, decisions of monitoring with about twenty of them proposed by our model, seven objectives and about ten performance indicators are selected. The model allowed a decision support according to the three decisional levels to monitor the decisions of PSA supply chain. The model designed integrates all the functions of the supply chain, allows too well understand the PSA's supply chain which remains valid for any industry. We found that the decision system of the PSA Kénitra group is in adequacy with our model. This study is under development and the enrichment of the decisions, objectives and indicators is still pursued. The proposed is model is targeted to fit as much as possible the complex supply chain relality with the majority of the functions (strategies, objectives, decision variables, indicators...) chosen with some specific adjustement to PSA Morocco. A diagnosis of the supply chain is in progress on new technologies of the 4.0 industry to analyze their degree of integration in various supply chain activities and their impact on competitiveness. The results will be published in a forthcoming communication.

CONCLUSION

This paper presents the PERFLOG Methodology with the ideas for new reference decision-making models of the supply chain GRAILOG-Cop and GRAILOG-Exp from the design of a network of partners to the exploitation of the supply chain. During the operational phase, indicators become a key issue for decision making. So, this work presents also a reference grid for performance indicators. However, the implementation and usage of these PI is crutial for the appropriate control of the SC. So, it is proposed to link the 4.0 technologies to the different life cycle phases of the PI's and to each Pi presented in the reference grid.

MOSIM '20 -November 12-14, 2020 -Agadir -Morocco This new methodology highlignts big data, artificial intelligence, digital twin and Iot and brings factors of competitiveness, optimizing management on a large scale certainly useful for instance for the automotive industry and its ecosystem suppliers, customers, etc.

  dedicated to defining objectives, decision variables and performance indicators. The final stage is dedicated to linking indicators and technologies in Industry 4.0.

Figure

  Figure 1 : PERFLOG Method

  below shows the contribution of each technology to a phase of the indicator's life cycle.

Figure. 2 :

 2 Figure.2: Technologies 4.0 supporting KPI lifecycle Data acquisition: In this phase it is essential to have reliable, relevant data in the nearest field and in real time.Often, ETL (Extract Transform Load) tools are used but in a very traditional way. Big data is interesting in this phase to process all the required data. Given the importance of the data flow, it can be assigned to most phases of the acquisition, calculation and restitution life cycle. Data Storage is only a repository and data cleaning for which big data processing is not necessary. For the

Virtual Reality, Cyber Security, Internet of Things (IoT) Energy Internet, Collaborative Robots, Additive Manufacturing & 3D Printing, Machine Learning, Simulation and Internet of Services (IoS).

  , the authors refer to Cyber-Physical Systems, the Internet of Services and the Internet of Things as the basis for Industry 4.0 technologies, other authors have taken a broader view:[START_REF] Gamache | Etude du potential de l'industrie 4.0 quand à la transformation de la[END_REF]) conducted a study of 51 publications to highlight the tools most frequently associated with Industry 4.0 such as Big data, Smart factory, Cloud computing, Internet of things, M2M, Internet of services, additive manufacturing...

	From our literature review one can highlight technology
	groups related to Industry 4.0. For this purpose, this
	work exploited a list of 15 most relevant technology
	groups that can be organized as follows: Big Data /
	Artificial Intelligence, RFID, Digital Twin, Cloud
	Computing,	Cyber	Physical	System,	M2M
	Communication,