Paracamelus cf. aguirrei from Çobanpinar (Turkey) is described. Rodents from that locality suggest a Late Turolian or Latest Miocene age, indicating that this is one of the oldest records of the genus. Paracamelus dispersed from North America in a relatively short period during the Late Turolian (MN13) into the extensive open and dry environments from central Asia to North Africa, as well as into southern Spain.
Cette note décrit Paracamelus cf. aguirrei de Çobanpinar (Turquie). Il s'agit de l'un des plus anciens Camelidae de l'Ancien Monde car, d'après la faune de rongeurs, cette localité date du Turolien supérieur ou du Miocène terminal. La dispersion de Paracamelus de l'Amérique du Nord vers l'Ancien Monde s'effectue dans un court intervalle de temps au Turolien supérieur (MN13), tandis que son aire de répartition correspond à la ceinture aride allant de l'Afrique du Nord et de l'Espagne à l'Asie centrale.
Camelidae, Turolian, Late Miocene, Turkey, dispersal eventCamelidae, Turolien, Miocène supérieur, Turquie, dispersionmiscellaneousCommunicated by Philippe TaquetVersion abrégéeIntroduction
Les Camelidae qui apparaissent à l'Éocène supérieur en Amérique du Nord se dispersent tardivement, d'une part, vers l'Eurasie au Miocène supérieur et, d'autre part, vers l'Amérique du Sud, à l'occasion du « Grand échange interaméricain », au début du Pliocène. Leurs représentants actuels sont des vigognes, guanacos, lamas et alpacas en Amérique du Sud et les chameaux et les dromadaires dans l'Ancien Monde.
Les Camelidae les plus anciens de l'Ancien Monde sont classés dans le genre Paracamelus, qui est considéré comme l'ancêtre des chameaux et dromadaires actuels. Ce genre, essentiellement pliocène, est aussi reconnu dans quelques sites du Miocène supérieur d'Eurasie. Les chameaux et dromadaires actuels vivent dans la zone aride allant de l'Afrique du Nord à l'Asie centrale. L'aire de répartition des sites à Paracamelus du Miocène supérieur se trouve également dans cette même zone.
Le gisement de Çobanpinar est situé à 50 km au nord-ouest d'Ankara en Anatolie centrale. Il a livré, entre autres grands et petits mammifères, des restes appartenant à Paracamelus. Si ce gisement est bien d'âge Turolien moyen [11], le Camélidé de Çobanpinar serait la plus ancienne occurrence de cette famille en Eurasie. À la lumière des connaissances actuelles sur la faune de ce gisement et sur la systématique des Camelidae, il convient donc de reconsidérer la dispersion initiale de la famille dans l'Ancien Monde et aussi l'âge de ce gisement.
Systématique
Famille Camelidae Gray, 1821
Paracamelus cf. aguirrei Morales, 1984
Matériel de Çobanpinar. Mandibule gauche, avec DP3–M1, mandibule droite, avec DP2–M1, symphyse avec DI1–DC1 droites et DI1 gauche, DC1 gauche. Tout le matériel appartient à un même individu (Fig. 1), conservé au Musée d'histoire naturelle du MTA à Ankara.
Description. La symphyse est étroite. DI1–DI3 ont des couronnes hautes ; en particulier, la base de la couronne est plus basse distalement que mésialement sur la DI3. Les bords coupants des incisives de lait sont bien recourbés. La couronne de la canine de lait est basse, tandis que celle de la canine définitive est plus élevée. Le corps mandibulaire est bas, mais relativement épais. La taille des dents jugales augmente de l'avant vers l'arrière. La DP2 possède un seul tubercule, avec des crêtes antérieure et postérieure, et deux racines. Le schéma occlusal de la DP3 est plus compliqué, avec ses trois crêtes issues du protoconide et d'autres cuspides accessoires. Son lobe postérieur est nettement plus large que le lobe antérieur. La DP4 a une couronne élevée, une surface occlusale sélénodonte, sans ectostylide, et une face linguale plate. Les DP4 et M1 ne possèdent pas de pli caprin. La couronne de la M1, la plus haute, mesure 37 mm à l'entoconide. Les dimensions de cette molaire suggèrent une espèce de grande taille.
Comparaison. La morphologie des incisives, la réduction des dents jugales antérieures, la couronne élevée et le schéma sélénodonte des DP4 et M1 sont des caractères de Camelidae et excluent l'attribution de ce matériel au ruminants s. str. Chez Paracamelus, les prémolaires sont moins réduites que chez Camelus[8], ce qui confirme l'attribution du matériel de Çobanpinar au premier genre. Son espèce type P. gigas provient de Chine et indique un animal de grande taille. Les spécimens de Venta del Moro et de Çobanpinar sont assez proches en taille de P. gigas, bien que légèrement plus petits. Les Camelidae de l'Ancien Monde montrent une diminution de la taille durant le Pliocène et Pléistocène, représentés par des espèces P. alexejevi, P. alutensis et P. kuljenensis.
Discussion
Les Camelidae du Miocène supérieur ont été mentionnés ou décrits des gisements de Venta del Moro [15], [16], [18] and [19], Librilla [1], Odessa [5], Wadi Natrun [23], Yushe [7], Eldar et Ischim River [25] et Jalalabad [20]. Leur présence à Eldar semble être douteuse [5]. Les datations radiométriques ou corrélations bio- et/ou magnétostratigraphiques des autres gisements montent qu'ils datent tous de la fin du Turolien. Ceci remet en question l'âge MN12 attribué initialement à Çobanpinar. Ce gisement a récemment livré 24 dents de rongeurs, déterminées comme Byzantinia sp. I (petit), Byzantinia sp. II (grand), Parapodemus sp., Occitanomys cf. provocator De Bruijn, 1976, Cf. Paraethomys sp., Pseudomeriones cf. rhodius Sen, 1977, Tamias sp. et Hystrixprimigenia (Wagner, 1848). Parmi ces taxons, Byzantinia est un genre commun des gisements vallésiens et turoliens de Grèce et de Turquie, mais il s'éteint avant la limite Mio-Pliocène. Occitanomysprovocator n'est connu qu'en Grèce dans le gisement de Chomateri, dont l'âge serait MN12 ou MN13 [3]. Pseudomerionesrhodius a été décrit du gisement de Maritsa (MN14), mais signalé également à Ano Metochi 3 (MN13) en Grèce [13]. La forme de Çobanpinar diffère de celle de Maritsa par ses caractères primitifs (couronne dentaire plus basse, M1 et M1 moins allongées et plus étroites, M2 avec un protosinuside profond), comme le sont également les spécimens d'Ano Metochi 3. Les rongeurs de Çobanpinar suggèrent plutôt une corrélation avec le Turolien supérieur (MN13), bien qu'on ne puisse définitivement exclure un âge un peu plus ancien, en particulier à cause de l'absence de dent attribuable à Apodemus qui apparaı̂t durant cette zone. Cependant, cette absence peut aussi bien être due au faible nombre de spécimens récoltés.
L'âge de la limite MN12/MN13 est estimé à 6,8 Ma, essentiellement sur la base de la magnétostratigraphie des gisements espagnols. Dans cette même région, la zone MN13 est subdivisée en trois sous-zones (M1–3) avec des limites à 6,3–6,1 Ma et à 5,8 Ma [4]. La sous-zone M2 est caractérisée par plusieurs événements de dispersion à grande échelle de taxons, tels que Hippotamus, Parabos, Agriotherium et Mesopithecus. On pourrait y ajouter les Camelidae, qui, d'après les données disponibles, semblent bien se disperser dans l'Ancien Monde durant cette sous-zone. Cela induit un âge entre 6,3 et 5,8 Ma pour le gisement de Çobanpinar.
Introduction
Camelidae originated in the Eocene of North America, where they became first diverse in the Neogene, later they declined and finally went extinct. However, before going extinct there, they dispersed toward two areas where they still live today. They dispersed into the Old World during the Latest Miocene and, during the Late Pliocene Great American Exchange, they entered South America, where they are still represented by wild vicuña and guanaco and domestic llama and alpaca. The earliest Old World camels placed in Paracamelus are descendants of the North American Procamelus or Megacamelus, and ultimately gave rise to the living bactrian camel (Camelus bactrianus) and the domestic dromedary (C. dromedarius) [19] and [22].
Initially, this dispersal into the Old World was believed to be a Villafranchian event. However, when Paracamelus was described from Venta del Moro in Spain, it became clear that the dispersal occurred during the Latest Miocene (Neogene Mammal Unit MN13) [15]. Camels are adapted to arid environments and live today in the arid belt extending from North Africa into Central Asia, and the distribution of the fossil finds is also essentially in this area. Therefore, these camels are believed to have reached Spain from North Africa and not through Europe. Camel fossils tend to be rare in mammal localities, particularly in Late Miocene ones. Çobanpinar in Turkey, placed in MN12 [11], yielded new material of Paracamelus. Thus, it seems to be the oldest Old World camel known, suggesting a still older date for the dispersal event. This locality also yielded some rodents. The aim of this paper is to describe the new material and to discuss the age of the locality and that of the camel dispersal event.
Systematic description
Family Camelidae Gray, 1821
Genus Paracamelus Schlosser, 1903
Type species: Paracamelusgigas Schlosser, 1903.
Other species described: P.khersonensis (Pavlow, 1903); P. (N.) alutensis (Stefanescu, 1910); P.bessarabiensis (Khomenko, 1912); P. (N.) kuljenensis (Khomenko, 1915); P.praebactrianus (Orlov, 1927); P. alexejevi Khavesson, 1950 and P.aguirrei Morales, 1984.
Remarks: P.khersonensis was originally placed in the American genus Procamelus. Later Paracamelus became in use. Harrison [6] included Paracamelus in Camelus and was followed in this by McKenna and Bell [10], but not by the majority of the authors who worked on Paracamelus. Therefore, we maintain that name. Neoparacamelus Khavesson, 1954 was described as a subgenus of Paracamelus to include some species of very small size.
Paracamelus cf. aguirrei Morales, 1984
Synonymy for P.aguirrei and P. cf. aguirrei: 1902 Camelide; Stromer [23]: 110–111, Fig. 1. 1973 Paracamelus spec.; Raufi and Sickenberg [20]: 84–90, Figs. 10c, 10f. 1980 Paracamelus sp.; Morales, Soria and Aguirre [16]: 139–142, Fig. 1a. 1984 Paracamelusaguirrei nova sp.; Morales [15]: 135–161, Figs. 16–19. 1993 Paracamelus; Pickford, Morales and Soria [18]: 701, Fig. 1. 1995 Paracamelus; Pickford, Morales and Soria [19]: 641–648 (material from Venta del Moro), plates 79–81. 1999 Paracamelusaguirrei; Van der Made and Morales [9]: 221–223, Figs. 22.1–22.4.
Material
Left mandible with DP3–M1. Measurements (length/ basal length × width first lobe–width second lobe–width third lobe–in mm): DP3, 20.0×8.9–10.1; DP4, 46.7/42.7×14.2–15.7–17.6; M1, 43.6/(⩽39.5)x ⩾19.1–(⩾22.2).
Right mandible with DP2–M1. Measurements: DP2, 13.0×5.8–5.4; DP3, 19.2×8.5–10.4; DP4, 47.4/43.3 ×14.4–15.6–17.6; M1, 42.6/(⩽38.1)×(⩾18.6)–(±22.8).
Symphysis with right DI1–DC1 and left DI1, and root of DI2. Measurements (meso-distal width/basal meso-distal width × labio-lingual diameter): right DI1, 13.1/10.9×8.9; DI2: 13.5/11.4×9.3; DI3: 12.3×6.0; DC1: 14.8×6.3; left DI1, 12.5/10.4×9.3.
Left DC1. Measurements: 16.5×6.7.
All specimens belong to a single individual and are housed in the collections of the Natural History Museum (MTA) in Ankara under number 3007.
Description
The symphysis is very narrow. The DI1–3 (Figs. 1A–1D) have high crowns with clearly marked bases, and especially in the DI3, the crown base is much lower distally than mesially. The ensemble of the milk incisors have a very curved cutting edge, and the tips of the crowns curve in mesial direction, unlike in ruminants, where they curve distally, forming a wider cutting edge. The endocristas are not well developed. The DC1 has a remarkably low crown and resembles the DC1 of Camelus[22], while the permanent canine tends to be larger.
The mandible is not very deep and relatively thick (Figs. 1E–1F), as is common when the deciduous teeth are still in function. There is a marked size increase from the anterior to posterior cheek teeth, which probably reflects the same state in the permanent dentition. The DP2 has a single cusp with an anterior and a posterior crest and two divergent roots. The DP3 has three crests directed from the protoconid in anterior, postero-lingual and postero-buccal directions. The latter leads to the hypoconid and continues postero-lingually; the postero-buccal crest forms a marked bulge. The posterior lobe is much wider than the anterior lobe. The DP4 is high crowned and selenodont, without interlobular columns and with a flat lingual wall; each one of its tree lobes has a narrow and shallow fossid. The DP4 and M1 do not have a goat-fold. The M1 has a still higher crown, over 37 mm at the entoconid. The size of this tooth suggests a very large animal.
Taxonomic discussion
The combination of the incisor morphology, the strong reduction of anterior cheek teeth and the high crowned selenodont DP4 and M1 fit a camel, but not a ruminant. The species of Paracamelus are characterised by a less reduced premolar row than in Camelus bactrianus[8]. The anterior milk molars in the specimens from Çobanpinar are small, but the DP2 may be lacking in Camelus[22]. These observations, and the large size point to Paracamelus.
The generic and specific names Paracamelus gigas were introduced for two molars from China, believed to be a first and second upper molar, with sizes 47×38 and 50×41 mm, respectively [21]. The supposed M1 is an isolated tooth and seems (too?) large for an M1, and may represent an M2. Because this specimen was figured and because Schlosser [21] did not indicate a holotype, it might be taken as the lectotype. We do not know, however, where this material is, or whether it still exists, and therefore merely take the specimen as the most representative of the two.
The length of upper and lower M1 tends to be comparable, but in unworn teeth, there is a notable difference between the maximum and basal length. In Çobanpinar, the occlusal length is 43.6 and 42.6 mm; the crown base is still in the mandible, and the basal length is ⩽39.5 and ⩽38.1 mm. Zdansky [26] assigned some material from China to P. gigas, including an M1 (L=34.7 mm) and M1 (L =36.0 mm); since these specimens are worn, it is difficult to interpret [8].
The remains described by Schlosser [21] suggest thus particularly large animals, approached by those from Venta del Moro and Çobanpinar and much larger than the ones described by Zdansky [26]. The Old World camels show a general tendency towards smaller sizes. Considering the limited material available, we do not intend a revision of the genus, but note that the material from Çobanpinar is either referable to the very large P. aguirrei or to P. gigas.
General discussion
Camels of Miocene age are cited or described from Venta del Moro [15], [16], [18] and [19], Librilla [1], the Odessa limestone [5], Wadi Natrun [23], Yushe [7] and from Eldar and the Ischim River [25] and Jalalabad [20].
Eldar is either correlated with MN11 [11], or with MN10 [3], but camels are not included in the faunal list from that locality [5]. We did not obtain information on the Ischim River locality. Librilla is situated in beds overlying the rocks radiometrically dated between 6.2±0.3 and 7.00±0.03 Ma [14]. Venta del Moro was estimated to be 5.8 Ma old on the basis of biostratigraphy and magnetostratigraphy [17]. Wadi Natrun is correlated with MN13 [12]; however, this correlation is questionable, since this locality also yielded a derived murid Saidomys natrunensis James and Slaughter, 1974, which is recorded elsewhere only in Pliocene localities. It cannot be assumed that the camel and murid are originated from the same horizon. The first appearance of Paracamelus in the Yushe area is at 5.5 Ma [7]. The phalanx from Jalalabad [20] is comparable in size to the one from Venta del Moro, suggesting a similar age, but the associated fauna is too poor to confirm this age. The locality of Çobanpinar has been placed in MN12, though no explanation was given [11]. This would suggest that the oldest remains of an Old World camel might be those from Çobanpinar.
One of us (S. Sen) collected a small sample of sediment of less than 100 kg at Çobanpinar from the level where the large mammals have been collected. From this sample, 24 isolated rodent teeth were obtained by screen washing. The following taxa are present: Byzantinia sp. I small (3 specimens), Byzantinia sp. II large (3 specimens), Parapodemus sp. (2), Occitanomys cf. provocator De Bruijn, 1976 (5), Cf. Paraethomys sp. (1), Pseudomeriones cf. rhodius Sen, 1977 (8), Tamias sp. (1), and Hystrixprimigenia (Wagner, 1848) (1).
Byzantinia is known from Turkish Late Miocene localities, which tend to have two species of different size and morphology, and from several Greek Turolian localities, but does not survive into the Pliocene. Occitanomys cf. provocator was described from Pikermi (Chomateri), a locality that is placed either in the Late [2] or Middle Turolian [3]. The type locality of Pseudomerionesrhodius is Maritsa (MN13/14) in Rhodes (Greece), and it was also recorded at Ano Metochi 3 (MN13), northern Greece [13]. Pseudomeriones from Çobanpinar is similar in size, but more primitive than the specimens from Maritsa in having less elongated M1 and M2, and a deeper protosinusid on the M2. The rodent association suggests a Late Turolian age (MN13) for Çobanpinar, and confirms that it is one of the oldest Old World localities with a camel, but does not support a Middle Turolian (MN12) age. An MN13 age is corroborated by the suid Propotamochoerusprovincialis, which is recorded from Çobanpinar and which is not known before MN13. Accepting a size decrease in Paracamelus, the large size of the remains from Çobanpinar fit also well an MN13 age.
The MN12–13 transition has an estimated age of 6.8 Ma, and within MN13 three subunits (M1–3) are recognised in the Turolian type area (Teruel Basin, Spain), with transitions at 6.3–6.1 and 5.5 Ma [4]. Subunit M2 is characterised by several long-distance dispersals of large mammals (e.g., hippos, the bear-like Agriotherium, and the suid Propotamochoerusprovincialis). Other dispersals are not recorded in the Turolian type area, but in other parts of western Europe (the camel, the bovid Parabos, the cercopithecoid Mesopithecus), or are dispersals into a much wider area than western Europe (as is the case with the camel, Agriotherium and Propotamochoerusprovincialis). The available data suggest that: (1) camels dispersed into Spain within the middle part of MN13, posterior to 6.3 Ma and anterior to 5.8 Ma, (2) that this dispersal may have been part of an event involving the dispersal of other taxa, (3) the appearance of camels in Spain is not later than in Asia or Africa, and (4) the later appearance of camels in areas between the Bering Strait and Spain (e.g., Yushe) may either reflect an incomplete record (camels tend to be rare) or ecological circumstances.
Conclusion
Paracamelus from Çobanpinar is one of the oldest camels of the Old World. Other early Paracamelus are found in the Latest Miocene (MN13 or equivalent) localities of Librilla and Venta del Moro in Spain, Yushe Basin in China and Jalalabad, Afghanistan. Several Pliocene localities in Eurasia and North Africa also yielded remains of Paracamelus. The dispersal of camels into the Old World seems to have occurred after 6.3 Ma and before 5.8 Ma, possibly during a time of intensive faunal exchange between the different continents. The limits of the distribution of Talpa, Tapirus, Anchitherium, cervids and some other mammals suggest the presence of arid or dry environments in the Middle East, inhibiting their dispersal into Africa and the Indian Subcontinent during most of the Mio-Pliocene [24]. All Miocene camel localities are within the present-day arid belt that extends from North Africa (and southern Spain) to central Asia, and again suggest that some dry environments existed during the Late Miocene and that Paracamelus was adapted to them.
Acknowledgements
We thank E. Güleç, E. Ünay and G. Saraç for their help in the MTA collections. JvdM received support from various institutions through projects PB96-1026-C03-02 and PB98-0513 and the ‘Unidades Asociadas’ program of the CSIC. The record of small mammals at Çobanpinar by S. Sen was facilitated by the International Sinap Project (1989–1995).
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Paracamelus cf. aguirrei from Çobanpinar. A–D: Syphysis (upper row, from left to right: left, labial, lingual and right views); E–G: left mandible (lingual, occlusal and buccal views). Natural size.
Paracamelus cf. aguirrei de Çobanpinar. A–D : Symphyse en vues gauche, labiale, linguale et droite ; E–G : mandibule gauche en vues linguale, occlusale et latérale. Grandeur naturelle.