We use I/i, C/c, P/p, M/m, and D/d for upper/lower incisors, canines, premolars, molars, and deciduous molars, respectively. Dimensions are given in mm, except when mentioned.

Abbreviations: ant, anterior; ect, ectometaloph; est, estimated; FAD, first appearance datum; H, height; L, length; LAD, last appearance datum; max, maximum; post, posterior; S, synclinid; Sd, sinusid; W, width.

Institutional abbreviation: MNHN, Muséum National d’Histoire Naturelle, Paris.

Order RODENTIA Bowdich, 1821

Family THERIDOMYIDAE Alston, 1876

Genus Protechimys Schlosser, 1884

Protechimys cf. lebratierensis Vianey-Liaud, 1998

Fig. 2

This taxon is only documented by a damaged right mandibular fragment, bearing p4 (wear surface: L = 2.26; W = 1.66; labial H = 1.13; total crown L = 2.46; W = 2.05; Fig. 2.1) and a broken m1 (total crown L = 2.07; H = 1.10), and a well-preserved isolated right m1 (wear surface: L = 1.74; W = 1.28; labial H = 1.67; total crown L = 2.03; W = 1.84; Fig. 2.2). It has been compared directly to the type material, from Lébratières 14 (MP24, Quercy). The teeth display the primitive features of Protechimys. The mure is still separating the synclinid III from the sinusoid. There is a weaker difference in enamel thickness between the mesial and distal flanks of anticlinids than in P. truci, which is related to the crown weakly inclined mesio-distally (not inclined in P. truci). The wear surface is plane and the teeth are moderately worn. The synclinid I is not observed, but the shape of the synclinid II and the thickness of the anticlinids may indicate its occurrence on unworn teeth; the lingual wall of synclinids II and IV is closed; the ratio synclinid III/sinusid is comparable with that observed on equally worn specimens (Log H/L = 0.04) from Lébratières 14 (Log area Sd/SIII = 0.77; Log perimeter Sd/SIII = 0.49), and a little higher than in equally worn specimens of P. truci (Vianey-Liaud, 1998: 261–262). Morphological characters, occlusal dimensions, and height of the available teeth fit well with P. lebratierensis, but the material is too scarce to ascertain a formal specific synonymy with the latter taxon.

Order ARTIODACTYLA Owen, 1848

Family CAINOTHERIIDAE Camp & Van der Hoof, 1940

Genus Caenomeryx Hürzeler, 1936

Caenomeryx sp.

The material includes three fragmentary hemimandibles, morphologically very similar and comparable in size. They all belong to adult individuals. 27.07 is the most complete specimen, as it preserves left p3-m3; other specimens preserve left p3-m1 and m2-m3, respectively. Although these specimens show the diagnostic features of Caenomeryx in both their morphology (mandible massive and very wide beneath the molar area; p3 with an incipient talonid disto-lingually opened, p4 with a strong metaconid and paraconid) and their size, discriminating species on the basis of the sole lower dentition is quite hazardous. Caenomeryx is known by two species, C. procommunis and C. filholi, primarily documented in unallocated-undated localities from the Phosphorites of Quercy. The material from Moissac-IV is close in size and morphology to the newly dated material from several MP23-MP24 localities of Quercy (Blondel, 2005). Yet, the lack of upper dentition that bear most diagnostic features of the two species referred to Caenomeryx leads us to leave these specimens as Caenomeryx sp.

Family LOPHIOMERYCIDAE Janis, 1987

Genus Lophiomeryx Pomel, 1854

Lophiomeryx chalaniati Pomel, 1854

Fig. 3.1–3

The material includes several fragmentary maxilla, lower jaws, and astragali. Interestingly, upper and lower decidual dentition is fairly well represented (e.g., 39-08 and 05-10, preserving D2-3, and D3-4 respectively), and adult specimens display a range from just erupted to heavily worn dentition.

The upper dentition is characteristic to Lophiomeryx (Fig. 3.1): P4 has strong and rounded styles, and the labial side of the labial cusp is almost flat; the upper molars are approximately square in occlusal outline, with four cusps; parastyle and mesostyle are labially salient; the labial rib of the paracone is poorly expressed, and the labial face of the metacone lacks such a rib so that it appears concave. The metaconule is variably reduced on M3; it is very small on 26-10, giving this molar a sub-triangular outline. This feature is sometimes thought as characteristic of L. mouchelini, a species known in MP22 (Brunet & Sudre, 1987).

The lower dentition displays the diagnostic features of L. chalaniati: the paraconid is very faint or absent in p2; the transversal crests are poorly developed in p3, the metaconid is strong on p4, and just lingual to the protoconid (Fig. 3.2B). However, the hypoconulid of m3 is linked to the second lobe of the molar through either a unique crest (21-07) or two crests (20-07 or 38-08). Again, (Brunet and Sudre, 1987) advocated that the way the third lobe of m3 is related to the second lobe, through one or two crests, was a feature differentiating L. chalaniati from L. mouchelini, respectively. Consequently, and despite the size range of the specimens that globally fits well with that of L. chalaniati (especially the series from Le Garouillas, MP25), we cannot exclude that both L. chalaniati and L. mouchelini are represented among the material presently available from Moissac-IV.

The astragali are all fairly weathered and the sustentacular facet of 57-08 is damaged, but the crests delimiting articular surfaces are generally discernible. Characteristically, the proximal and distal trochleae are not aligned, the distal pulley being slightly rotated medially (Fig. 3.3). The medial ridge bordering the sustentacular facet is well marked, and the sustentacular surface occupies about two thirds of the total transversal width of the astragalus. The sustentacular facet is slightly concave, due to the presence of a longitudinal groove. The ridge separating the cuboid and the navicular articular surfaces is not visible on the distal trochlea as in some specimens of Lophiomeryx chalaniati from Quercy (Martinez and Sudre, 1995), but it may be due to post-mortem weathering. Astragali are morphologically similar and the observed range of the available material indicates that all belong to L. chalaniati.

Family GELOCIDAE Schlosser, 1886

Genus Gelocus Aymard, 1855

Gelocus sp.

47-08 is an upper molar (probably M1), morphologically distinct in showing very poorly developed styles; the postprotocrista is almost transversal, and it does reach the base of the pre-metaconule crista medially as in the upper molar of Lophiomeryx. The labial side of the paracone is strongly ribbed while labial ribs are poorly expressed in Lophiomeryx. These features of 47-08 are reminiscent to those of M1-2 s of Gelocus; size is comparable to that of G. villebramarensis (western Europe, MP22); Gelocus gets extinct at MP25 (Métais and Vislobokova, 2007).

Family DICHOBUNIDAE Turner, 1849

Genus Metriotherium Filhol, 1882

Metriotherium aff. mirabile

Fig. 3.4 and 5

The available material includes a left isolated M3 (22.08) and a right mandible with p3-m3 (24.08), which display diagnostic features of the late dichobunid Metriotherium. 22.08 has a reduced hypocone and no distal wear-facet on the distal side (all three features pointing to an M3). It is selenodont, with sharp and buccally shifted pre- and postcristae on buccal cusps, a strong mesiobuccal extension, a distally crested hypocone, and lingual roots forming a single lingual pillar; the hemimandible 24.08 is broken in front of the p3 and it preserves a small portion of the ascending ramus. p3 is a slender tooth with a wide transversely extended mesiostylid and a strong cuspid distal to the protoconid, here considered as a hypoconid; the latter presents a sharp distal cristid running to the distal border of the tooth. There is no trace of distal cingulid. p4 has a strong mesiostylid (although smaller than in p3), a strong metaconid, and two distinct distal cuspids; the distal part of p4 is inflated and it exceeds the protoconid width. The lower molars are heavily worn so that their finest structures are not observable. However, they display closely apposed mesial cuspids and sharp pre- and postcristids on protoconid and hypoconid, observable by the crescentic wear pattern.

The buccal side of 24.08 presents two circular depressions (6.7 and 5.0 mm wide, respectively) below m3, which most probably correspond to predation marks, due to a large flesh-eater (carnivore or creodont?).

Metriotherium is far from being well-known, and M3 is only documented for M. mirabile so far (Sudre, 1995). 22.08 differs from the M3 of M. mirabile by a more buccal orientation of the postmetacrista, which confers to the crown a more rectangular outline. An isolated p3 from Le Garouillas (M. mirabile; Sudre, 1995) is morphologically similar to 24.08, but larger (16.7 vs. 13.8). The p4 from Moissac-IV resembles that of M. mirabile, but the distal part of the former is more inflated. The lower molars of 24.08 lack the strong labial indentation between the protoconid and the hypoconid as observed in M. minutum and M. sarelense (Astruc et al., 2003 and Sudre, 1995) and there is no hypoconulid constriction either. The buccal cingulum is well developed on m1-2, which also occurs in some (larger) specimens of M. mirabile from Le Garouillas (Sudre, 1995). Overall dimensions of 24.08 (L m1–m3 = 43.0) compare well with those of the holotype of M. mirabile (Brunet and Sudre, 1980). Yet, the distinctive morphology of available material leads us to refer to the present specimens as M. aff. mirabile.

Family ENTELODONTIDAE Lydekker, 1883

Genus Entelodon Aymard, 1846

Entelodon sp.

Fig. 3.6

54.08 is a very large right lunatum (anteroposterior diameter = 47; proximo-distal height, mesial side = 46), which displays diagnostic features of Suina (Suoidea + Entelodontidae), such as the important mediolateral extension of the proximal articular facet, the presence of a deep notch for the anterolateral part of the scaphoideum, and the concavity of the anterior part of the magnum-facet. These characters differ from what is observed in other coeval large artiodactyls, i.e. Anthracotheriidae, the lunatum of which is mostly anteroposteriorly elongated, with a sub-straight medial edge (Kowalewsky, 1874). The huge size of 54.08 does not coincide with any Paleogene suoid, but its size, proportions, and morphology fit those of the entelodontid Entelodon. 54.08 is slightly larger than the lunatum of Entelodon magnum described by (Kowalewsky, 1876), but its proximal side compares well with the corresponding articular facet, as observed and measured on a distal radius of E. deguilhemi from Villebramar (Brunet, 1979). Postcranial morphology of entelodontids is far from being well-known, so we consider 54.08 as documenting Entelodon sp.

Family ANTHRACOTHERIIDAE Leidy, 1869

Genus Anthracotherium Cuvier, 1822

Anthracotherium sp.

Fig. 3.7

The lower incisor 14.08 (mesio-distal crown L = 16.0) has a spatulated and highly asymmetrical crown, and a long and straight root (Fig. 3.7). In lingual view, the crown lacks an endocristid and the endosynclinid is deep and distally displaced. The lingual cingulid is restricted to the mesialmost and distalmost parts of the crown. Enamel is more extended ventrally on the labial side than on the lingual side, implying deep pre- and postanticlinids. The distal part of the cingulid slightly extends on the labial side of the crown. The crown is mesio-distally elongated, with an apical wear-facet due to I2 and a distal one, concave, due to I3. Referral to the Entelodontidae was discarded because entelodontids present simple conical lower incisors with a strong lingual cingulid and a wear pattern markedly different from what is observed in 14.08. Lower incisors of Anthracotheriidae are rarely described, thus making comparisons difficult. However, contrary to what is observed in Microbunodontinae and Bothriodontinae, this tooth lacks an endocristid. The general morphology and the enamel finely wrinkled of 14.08 recall both Anthracotherium cuvieri (MP26), with higher and slender proportions, a 25% smaller size, and a reduced lingual cingulid, and undescribed specimens referred to A. cf. alsaticum (Villebramar) and to A. magnum (pers. obs., MJO). This specimen is tentatively identified as a left i3 of Anthracotherium sp.

Order PERISSODACTYLA Owen, 1848

Superfamily RHINOCEROTOIDEA Gray, 1825

Family RHINOCEROTIDAE Gray, 1821

Genus Protaceratherium Abel, 1910

Protaceratherium albigense Roman, 1912

Fig. 4.1–4.

The small and slender hornless rhinocerotid Protaceratherium albigense is documented by four mandibles and several isolated teeth. The left mandible 78-08 displays p3-m3 (estimated L for p2-m3 = 146), as well as the alveoli of i2 s (large, cylindrical, and procumbent) and of a biradiculate p2. The preserved part of the symphysis is slender, with a distal border located below the middle of p2, as is the foramen mentale. The ventral border of the corpus mandibulae is straight. The preserved part of the ramus is vertical. The foramen mandibulare is located well below the “jugal teeth neck line”. There is neither i3 nor c. Lower cheek teeth are brachydont and compressed labio-lingually, with a “m/w-shaped” occlusal pattern and no labial/lingual cingulids. Trigonids are angulous, forming an acute dihedron in occlusal view. Metaconids and entoconids are not constricted. Distal valleys are open lingually, deep and “V-shaped” in lingual view. The right mandible 018-07, from a younger individual, displays similar features. The juvenile mandible 02-10 is complete, with left and right procumbent i1 and di2, and functional d1-d4 and m1, but no di3/dc. The corpus displays a deep and wide incisura vascularis in its distal part. The ramus is low and developed sagittally. d2-d4 have no labial or lingual cingulids. d2 and d3 have a forked paralophid. The distal valley of d2 is almost closed lingually. On d3, the metaconid is deeply constricted but not the entoconid. On the right mandible 30-08, only d2-d4 are functional (L/Wd2 = 21/11; L/Wd4 = 28/16), which points to a young calf. The incisura vascularis is already marked at this ontogenetic stage. Dental features are consistent with those observed in 02-10. The I1 019-07 has an oval occlusal outline and a straight and prismatic root (total L = 48; crown H = 17; crown W = 10). The crown is bulbous, with a wear facet restricted to its distal side. The right P4 07-08 (L = 23; W = 29) is molariform, with a crista but neither crochet nor antecrochet. The paracone fold is attenuated. There is no metacone fold. The lingual and labial cingula are strong and continuous, with no inflection. The protocone is much thicker than the hypocone in occlusal view. The metaloph is constricted in its labialmost part.

The right M1 74-08 (L = 33; antW = 31.5; postW = 30.5) has a crochet, a strong antecrochet, and a constricted protocone. The lingual cingulum is restricted to a small median tubercle. The labial cingulum is low and continuous. The paracone fold is weak, but the paracone groove is deep, due to the parastyle lingually displaced. There is no metacone fold. The hypocone has an mesiolingual groove. The enamel is both wrinkled and corrugated. The left M3 10-07 (L = 27; antW = 29.5; ectL = 31.5) has a trapezoid occlusal outline. The ectoloph and metaloph are fused into an ectometaloph, but a vertical (vestigial) groove remains in the distal third of it. The mesostyle is developed distal to the strong paracone fold. The distal cingulum is low, oblique, and restricted to the distal half of the crown. The antecrochet is weak. There is neither crochet nor crista. The left D4 15-07 (L = 28.5; antW = 26; postW = 26) is low-crowned and square in occlusal view. The protoloph is bilobate, with an mesiolingual groove, and a strong antecrochet. The crista is thin, long and transversely oriented. The crochet is thin, bifid, sagittally oriented, and restricted to the top of the crown. The paracone fold is thick. There is no mesostyle. The metacone fold is thick and it widens nearby the neck. The lingual cingulum is almost continuous. There is no labial cingulum.

The concerned specimens are similar in size to the ones attributed to the hyracodontid E. gaudryi, but the presence of a deep incisura vascularis, of wrinkled and corrugated enamel, of a crochet on M1 and D4, of a distal groove on the ectometaloph and a low posterolingual cingulum on M3, of procumbent i1-di2, the absence of a metacone fold on P4 and M1, of di3-dc (juvenile) and i3-c (adult), the bulbous shape of I1, and the distal valley of d2 almost closed lingually form a combination characteristic of the rhinocerotid Protaceratherium albigense (Roman, 1912). With the exception of a constricted metaloph on P4, a small crochet on M1, somewhat reduced and smooth cingulids on lower teeth, the concerned mandibles and teeth are undistinguishable from the hypodigm of this species (Lihoreau et al., 2009 and Roman, 1912). On the other hand, these specimens are 20 to 50% smaller than the ones referred to other Oligocene European rhinocerotids such as Epiaceratherium, Ronzotherium, Mesaceratherium, and Diaceratherium (Brunet, 1979, Heissig, 1969 and Uhlig, 1999).

Family HYRACODONTIDAE Cope, 1879

Genus Eggysodon Roman, 1910

Eggysodon gaudryi (Rames, 1886)

Fig. 4.5–9

The small hyracodontid Eggysodon gaudryi, exceptionally abundant in Moissac-IV, is documented by four skulls (three adults and one juvenile), eight maxillae (three adults and five juveniles), ten mandibles (seven adults and three juveniles), as well as isolated teeth (permanent and deciduous) and a dozen postcranial elements.

All cranial features are plesiomorphic (sensu Antoine, 2002), with the exception of several apomorphic traits shared by adults and juveniles: processus zygomaticus maxillari with a low base; processus postorbitalis located on the tip of the squamosal; external auditory pseudo-meatus closed; occipital side vertical; pterygoid with a distal margin dipping strongly; short nasal bones; sagittal crest present on the basilar process of the basioccipital; processus posttympanicus and paraoccipitalis distant one from another. Other apomorphies were observed only in adults (nuchal tubercle developed, high zygomatic/frontal width ratio, mesial tip of the processus zygomaticus maxillari projected laterally, processus posttympanicus little developed, and median ridge present on the occipital condyle).

The mandibular symphysis is upraised and spindly, with a distal margin located below p2 (and d1). The foramen mentale is located below the middle of p2 (and d2). The sulcus mylohyoideus is present in juveniles and adults. The base of the corpus mandibulae is straight. The incisura vascularis is not marked. The ramus is inclined forward. The processus coronoideus is well-developed and the foramen mandibulare is located above the “jugal teeth neck line”. The permanent dental formula is 3I/3i +C/c +4P/3p +3 M/3m. LP1-M3 ranges from 138 up to 148 (mean = 143.2). Lp2-m3 ranges from 123 up to 145 (mean = 136.5). The anterior dentition is sub-vertically oriented, with C and c being the largest anterior teeth, as in the hyracodontid Eggysodon (Uhlig, 1999), and contrary to what occurs in all Oligocene rhinocerotids (Brunet, 1979, Heissig, 1969 and Ménouret and Guérin, 2009). P2 is quadratic, P2-M3 have a long parastyle, a wide and shallow paracone groove, and a weak paracone fold, and M1-3 always have an antecrochet, as in E. gaudryi and E. pomeli, but contrary to what is observed in E. osborni and E. reichenaui (de Bonis and Brunet, 1995, Roman, 1912 and Uhlig, 1999). The labial cingulum is always strong and continuous on P1-M1 and p2-m2, usually absent on M2-M3, and always absent on m3. According to (Uhlig, 1999), this condition distinguishes E. gaudryi and E. reichenaui from E. osborni and E. pomeli. All P3-4 are submolariform, and the paralophid of m1-m3 is short and low, contrary to E. reichenaui (Uhlig, 1999). On M1-3, the protocone is not constricted, contrary to what occurs in E. pomeli (Roman, 1912 and Uhlig, 1999). The entoconid of p2 is part of a short and low hypolophid, while the paralophid is not bifid in p2 and p3. Both features are only observed in E. gaudryi (Uhlig, 1999).

To sum up, all the morphological traits observed in Moissac-IV are consistent with those of E. gaudryi, from the late Early to early Late Oligocene of France (MP24-28; Uhlig, 1999). The only discrepancy concerns the small dimensions of the present sample, which are 15 to 30% smaller than other series referred to this species (de Bonis and Brunet, 1995, Roman, 1912 and Uhlig, 1999). These dimensions match the smallest representative of Eggysodon, E. osborni, from the Earliest Oligocene of western Europe (MP21-22; Uhlig, 1999).

To our knowledge, Moissac-IV yields not only the first comprehensive sample for E. gaudryi but also the only skulls referable to the hyracodontid Eggysodon. As a matter of fact, the current description is preliminary, as this material will necessitate further investigation.

Order CARNIVORA Bowdich, 1821

Family NIMRAVIDAE Cope, 1880

Genus Nimravus Cope, 1879

Nimravus intermedius (Filhol, 1872)

Fig. 3.8–9.

The material includes two left hemimandibles (28.08 and 28.10) that both preserve c, p3-m1 and lack the ventrodistal part of the dentary. The two specimens are morphologically very similar, 29.10 being from a larger and younger individual than 28.08. The dentary displays the diagnostic features of the genus, i.e. depth much greater below m1 than below p2, a ventral border narrow and somewhat pinched, no genial flange, although a small ventrally developed symphyseal apophysis is present, and a deep muscular fossa (for attachment of the digastric muscle) on the ventral side of the mesialmost part. The canine is small and bears two crests, one mesio-lingually and one, still preserving crenulations in 29.10, distally. The p1 is absent in both individuals. The p2 is absent in 28.08, which is quite unique in the species (only two specimens out of over 60 studied specimens); it was present in 29.09, although not preserved. The p3 and p4 are approximately the same height. Compared to p4, p3 is short, slender, and with a reduced (28.08) or vestigial (29.10) mesial cingular cuspid and a larger distal cingular cuspid. p4 is taller than the paraconid of m1; the mesial rim of the main cuspid is straight, while the distal rim is convex; the mesial cingular cuspid is larger than the distal one, which is diagnostic for the genus (Peigné, 2003). The m1 is typically trenchant and more elongated than in other nimravids; it lacks a metaconid and the talonid is short and more trenchant than in, e.g. Eofelis, Dinailurictis and Quercylurus. The m2 is not preserved but was present in both specimens. A right metacarpal is here assigned to the species on the basis of its size and felid-like morphology. Given the size of the species, this is a rather short bone (maxL = 57) compared to, e.g., felids similar or smaller in size such as Pseudaelurus quadridentatus (L = 59.3 for the Mc III MNHN Sa 634) and Promegantereon ogygia (mean = 67.65 for 35 specimens; Salesa, 2002). Compared to these felids, the distal part of the diaphysis of the Mc III of Nimravus intermedius is anteroposteriorly more compressed (but might partly result from post-mortem compaction); it also displays an articular facet for the Mc II that is both much less extended and less proximally developed, resulting in a much less concave facet for the magnum; the shelf forming the articulation with the Mc IV is less laterally developed.

Order CREODONTA Cope, 1875

Family HYAENODONTIDAE Leidy, 1869

Hyaenodon Laizer & Parieu, 1838

Hyaenodon dubius Filhol, 1873

Fig. 3.10.

H. dubius is documented by the right mandible 29.08, with p3-p4 and m2, and the roots of p2, m1, and m3. The mandible is deep (H = 35.2) and transversely compressed. The symphysis extends below p3. The masseteric fossa is deep, which implies the presence of a well-developed masseter muscle. The premolars are biradiculate and closely appressed: p3 and p4 are overlapped (brevirostric morphology). Based on the roots, p2 (estL = 13.2; estW = 6.7) was slightly shorter than p3 (L = 14.2; W = 8.0). p3 is shorter than p4 (L = 15.1; W = 8.7). The paraconid is not individualized and the talonid is short and narrow on the premolars. The only cusp present on the talonid is the hypoconid, transversely centred on it. No cingulid is present. The trigonid of m2 (L = 15.9; W = 7.0) is much worn labially, as usual in adult individuals of Hyaenodon. The paraconid is well shifted mesially. The paraconid and protoconid are of equal height. No metaconid is present. The talonid is very short and narrow. The only cusp present on the talonid is the hypoconid. The dimensions of m1 (L = 10.2; W = 7.0) and of m3 (L = 21.5; W = 7.4) are based on the roots.

The important reduction of the metaconid and talonid on molars permits to refer 29.08 either to the hyaenodontine Hyaenodon or to the hyaenaelurine Pterodon. Both genera are distinguished mostly based on cranial features (Polly, 1996). Yet, in 29.08, the teeth are less robust and the talonid is more reduced on m2 than in Pterodon, thus pointing to Hyaenodon. This long-lasting genus is known by eleven European species (Lange-Badré, 1979). Among the early Oligocene representatives of Hyaenodon, 29-08 compares well to H. leptorhynchus and H. dubius (MP21-MP23; BiochroM’97, 1997). Dental dimensions match those of H. dubius from Villebramar (MP22), and the robust and very appressed premolars are much similar to the specimens of H. dubius from Itardies (MP23; Lange-Badré, 1979).

Hyaenodon? leptorhynchus Filhol, 1873

Due to the presence of a disto-lingually oriented wear facet, 20.08 is interpreted as a left inferior canine. Most of the base of the crown has been worn out. The tooth is oval in occlusal view and no developed crest is visible. 20.08 has smaller dimensions (L = 9.1; W = 5.9) than the canines of H. dubius from Itardies (MP23). Such a size matches the specimens of H. leptorhynchus (Phosphorites of Quercy, old collections, MNHN). As a consequence and pending new discoveries, we tentatively refer 20.08 as to H.?leptorhynchus.

The present assemblage documents eleven distinct mammalian families: a theridomyid (rodent); a cainotheriid, a lophiomerycid, a gelocid, a dichobunid, an entelodontid, and an anthracotheriid (artiodactyls); a rhinocerotid and a hyracodontid (perissodactyls); a nimravid (carnivore); two hyaenodontids (creodonts). In terms of specific diversity, artiodactyls dominate, with six species out of 12 for the complete fauna, while the hyracodontid Eggysodon gaudryi, the lophiomerycid Lophiomeryx chalaniati and, to a lesser extent, the rhinocerotid Protaceratherium albigense, widely exceed all other taxa in terms of specimen abundance.

The Moissac-IV fauna is totally distinct from those of Moissac-I (MN1, Earliest Miocene) and Moissac-II (MP29, Late Oligocene), at species and/or genus level (Fig. 5; de Bruijn et al., 1992, de Bonis, 1973, Lihoreau et al., 2009 and Schmidt-Kittler et al., 1997). On the other hand, Moissac-III (MP26) and Moissac-IV have one species in common (the rhinocerotid Protaceratherium albigense), while theridomyid rodents and anthracotheriids are distinct, with Protechimys cf. lebratierensis and Anthracotherium sp. in Moissac-IV and Issiodoromys cf. pauffiensis and Elomeryx crispus in Moissac-III (Lihoreau et al., 2009), respectively.

The Moissac-IV assemblage compares well with other Early Oligocene faunas of the Phosphorites of Quercy, such as Cavalé for creodonts (MP22: Hyaenodon dubius + H. leptorhynchus; Vianey-Liaud & Schmid, 2009), Itardies for Ferae (MP23: Nimravus intermedius + Hyaenodon dubius; BiochroM’97, 1997), Lébratières 14 for the theridomyid rodent (MP24: Protechimys lebratierensis; Vianey-Liaud, 1998), and Le Garouillas, for most macromammals (MP25: Metriotherium mirabile, Plesiomeryx, Lophiomeryx chalaniati, Eggysodon gaudryi, and Nimravus intermedius; BiochroM’97, 1997). The “Middle” Oligocene locality of Las Peyres yields the same rhinocerotoid fauna (Fig. 1; Lihoreau et al., 2009).

As a whole, the concerned assemblage most probably documents the MP24 reference level, as synthesized for all recognized mammals in Fig. 5. The theridomyid Protechimys lebratierensis has been originally described on the basis of a rich assemblage (282 teeth) from the fissure filling Lébratières 14 (Phosphorites of Quercy; Vianey-Liaud, 1998). This locality also yields the issiodoromyine rodent Issiodoromys minor (grade 1), the evolutionary stage of which allows the concerned site to be correlated with MP24, as well are some poorer localities, such as Itzac-Delazens (Fig. 1; Vianey-Liaud, 1998). In our opinion, (Astruc et al., 2003) do not provide reliable arguments to push Itzac-Delazens up to MP25 and in turn, to extend the stratigraphical range of P. lebratierensis (Vianey-Liaud and Schmid, 2009). We consider P. cf. lebratierensis as a strong argument for Moissac-IV to be referred to MP24.

So far, the middle-sized creodont Hyaenodon dubius had a MP21-MP23 range (Ronzon, Villebramar, Cavalé, Itardies, and Montalbán; Lange-Badré, 1979). Together with the ramus transversely compressed, the robustness and the overlapping of the available premolars represent a derived condition for H. dubius (Lange-Badré, 1979), which would make sense with a referral to MP24 for Moissac-IV. The lophiomerycid Lophiomeryx chalaniati may have its FAD in Moissac-IV (MP24-28; Métais and Vislobokova, 2007). The dichobunid Metriotherium is documented in Early to early Late Oligocene localities from Southern France, ranging from MP22 (M. minutum, Villebramar) up to MP27 (M. sarelense; Astruc et al., 2003 and Sudre, 1995). The specimens from Moissac-IV display close affinities with M. mirabile. In Moissac area, Le Garouillas (MP25) yields M. mirabile and Puycelci (MP26; Fig. 1) M. cf. sarelense, respectively (Astruc et al., 2003). To date, the stratigraphical range of M. mirabile was MP25-MP26 (Astruc et al., 2003), but the small dimensions of p3 among the present specimens referred to as M. aff. mirabile would be consistent with an older age for Moissac-IV (i.e., MP24). The hyracodontid Eggysodon gaudryi spans the MP24-26 interval with certainty, and it perhaps extends up to MP28 (Hugueney, 1997, Ménouret and Guérin, 2009 and Uhlig, 1999). At a regional scale, E. gaudryi is mentioned in Latou, Las Peyres, and in various loci from the Phosphorites of Quercy (Fig. 1; de Bonis and Brunet, 1995, Roman, 1912 and Uhlig, 1999). Given the size increase observed both for this species and this genus throughout their stratigraphical range (Uhlig, 1999), the small dimensions of E. gaudryi in Moissac-IV would point to an age close to its FAD (Fig. 5). The entelodontid Entelodon spans the Early Oligocene in France, from Soumailles (MP21: E. antiquus), up to Saint-Martin-de-Casselvi (MP25: E. deguilhemi; Astruc et al., 2003 and Brunet, 1979). The cainotheriid Caenomeryx ranges from the middle Early to the Late Oligocene (MP23-?28; Erfurt and Métais, 2007). The rhinocerotid Protaceratherium albigense is well known throughout the middle Early-Early late Oligocene interval in southwestern Europe and Turkish Thrace (MP23-28; for review, Lihoreau et al., 2009). P. albigense, first defined in La Sauzière Saint-Jean (Fig. 1), was also recognized in Las Peyres, Lafrançaise and Moissac-III, all of them being referred to the MP25-26 interval (Fig. 1; Astruc et al., 2003, Lihoreau et al., 2009 and Roman, 1912). In Europe, Nimravus intermedius is known from a large sample from the old and undated collections of the Phosphorites of Quercy (Rémy et al., 1987). However, recently found and well-dated material comes from Early Oligocene sites: MP21 (Liptingen 1A, Germany; Scherzinger et al., 2005), MP22 (Mas-de-Got, La Plante 2, and Villebramar in France, Grafenmühle 10 and Möhren 13 in Germany), MP23 (Pech Crabit and Itardies, France) and MP25 (Rigal-Jouet, France). Outside Europe, the species is mentioned from a couple Late Eocene-Early Oligocene Asian sites (Peigné, 2003), but the classification of this material needs to be refined. The specimens from Moissac (e.g., L m1 ranges from 21 to 23.6) have greater dental dimensions than the holotype of N. intermedius (MNHN QU 9541; Peigné, 2003: Fig. 5). Considering only the material from well-dated sites, dental measurements (especially p3, p4 and m1) of Moissac specimens, which are distinctly greater than those of specimens from MP21 and MP22 sites, support an age ranging from MP23 to MP25 for that locality. The anthracotheriid Anthracotherium ranges from the late Middle Eocene up to the Late Oligocene in Asia and Europe (Lihoreau and Ducrocq, 2007). Its recognition in Moissac-IV is of no biostratigraphical use in the local context. Similarly, and according to Lange-Badré, 1979, Hugueney, 1997, and Astruc et al., 2003, the long-lasting creodont Hyaenodon leptorhynchus spans the Oligocene in France (MP22: Mas-de-Got, Villebramar; MP25: Saint-Martin-de-Casselvi; MP28: Pech-du-Fraysse, Cournon; MP29: La Milloque and Dieupentale) and Germany (MP22: Möhren 13; MP29: Gunzenheim). The tentative recognition of this species in Moissac-IV does not further constrain the stratigraphical age of it.

The new diversified meso- and macro-mammal assemblage from Moissac-IV is the oldest vertebrate fauna recognized in the Moissac area. It provides original data just prior the Early-Late Oligocene transition in the middle Garonne basin, a stratigraphical interval which was essentially documented by karstic fillings of the Phosphorites of Quercy so far.