Paschatherium levei, Hooker & Russell, 2012
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publication ID |
https://doi.org/ 10.1111/j.1096-3642.2011.00787.x |
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persistent identifier |
https://treatment.plazi.org/id/03DE8792-FF9C-655C-FC8A-F945FDCFFC1E |
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treatment provided by |
Marcus |
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scientific name |
Paschatherium levei |
| status |
sp. nov. |
PASCHATHERIUM LEVEI SP. NOV. ( FIG. 9 View Figure 9 )
? 2006 Paschatherium nov. sp., Condé-en-Brie; López- Martínez, Smith, Peláez-Campomanes & Smith, p. 270, table 1.
Etymology: After Dr J. Levé for finding key specimens of the species.
Holotype: R dentary with P 4 –M 1, MNHN.F.CB-303, from the Sables de Cuise , zone PE V, middle Ypresian , Early Eocene, Condé-en-Brie, France.
Paratypes: LP 4 , MNHN.F.CEB-314; RP 4, MNHN.F. Condé-1170-Levé; LM 1, MNHN.F.CB-313; RM 1 , MNHN.F.CB-824; LM 2, MNHN.F.CB-312; RM 2 , MNHN.F.CB-315; LM 3, MNHN.F.Condé-24-Levé; RM 3 , MNHN.F.PCB-0030; LP 4 , MNHN.F.CEB-321; LM 1, MNHN.F.CB-1088; LM 2, MNHN.F.Condé-137-
Levé; RM 2, MNHN.F.CB-1039; LM 3, MNHN.F.Condé- 1016-Levé; RM 3, MNHN.F.CB-1220; all Condé-en- Brie.
Age and distribution: Known only from the type horizon and locality.
Diagnosis: Large Paschatherium ( Table 3), mean length of M 1 3.12 mm (all other Paschatherium species are smaller). P 4 with postprotocrista confluent with metacingulum (shared with Pa. marianae ). M 1 hypoconulid slightly lingual of midline (central in the other species). M 1–2 precingulid a strong short ridge
OR, observed range.
(longer and/or more shelf-like in the other species). M 1 paraconid lingual in position (shared with Pa. marianae and Pa. plaziati ). M 1 pre-entocristid with straight edge (shared with Pa. marianae , Pa. plaziati , and Pa. russelli ).
Description
P 4: The two specimens show a metacone smaller than the paracone, a small hypocone, a paraconule with very weak postparaconule crista, and a metaconule with the premetaconule crista weak to lacking ( Fig. 9A View Figure 9 ). The postmetaconule crista joins the confluent postcingulum–metacingulum. There is a strong ridge-like ectocingulum and fairly strong precingulum. The postflexus is shallow. The parastyle varies in size. In one specimen ( Fig. 9A View Figure 9 2 View Figure 2 ) there is a low crest joining the hypocone to the trigon as in some specimens of Pa. plaziati (see Marandat, 1991). Indeed there is considerable similarity to Pa. plaziati . Paschatherium dolloi and Pa. yvettae have no postmetaconule crista. Paschatherium marianae has a taller metacone and an expanded shelf-like postcingulum creating a deep postflexus. The similar-sized B. phelizoni has cingula, hypocone, and conules much weaker and the postcingulum does not join the metacingulum.
M 1: Outline shape is rectangular but only slightly transversely elongate ( Fig. 9B View Figure 9 2 View Figure 2 ). The postflexi are very shallow, the preparacrista and postmetacrista are mesiodistally orientated and there is no postmetaconule crista, the metaconule being isolated from the confluent postcingulum–metacingulum. The paracone and metacone are of equal height ( Fig. 9B View Figure 9 1 View Figure 1 ). The hypocone is nearly as tall as the protocone. The general pattern is like the much smaller Pa. plaziati , although this species has a postmetaconule crista. Paschatherium dolloi has a more distobuccally orientated postmetacrista. Paschatherium marianae is more transversely elongate, has a smaller metacone and hypocone, deeper postflexus, more distobuccally orientated postmetacrista, and more mesiobuccally orientated preparacrista. In W. girardi and Berrulestes phelizoni , the outline is more triangular with a deeper postflexus, smaller metacone and hypocone, a postmetaconule crista, and weaker ectocingulum. B. phelizoni and B. poirieri have a postcingulum that does not join the metacingulum and more bulbous cusps. Early wear is dominantly shearing, whereas in the four last species tip wear dominates throughout ontogeny.
M 2: As is usual for this locus, the M 2 s are slightly trapezoidal in outline and relatively shorter mesiodistally ( Fig. 9C View Figure 9 ), but are otherwise very similar to M 1. One of the two specimens has a weak postmetaconule crista, but it does not reach the postcingulum– metacingulum and would probably not survive light wear. Most of the similarities and differences from the other species where this tooth is known are as on M 1.
M 3: The two specimens show considerable variation in outline shape and other features as is commonly the case in Paschatherium species. One has more angular corners than the other ( Fig. 9D View Figure 9 ). The postprotocrista bears neither metaconule nor its cristae and does not join the metacone. There is no postcingulum.
P 4: The tooth is semimolariform, the entoconid being smaller than the hypoconid, which is about half the height of the protoconid ( Fig. 9E View Figure 9 2 View Figure 2 , E 3 View Figure 3 ). The trigonid and talonid are of approximately equal width ( Fig. 9E View Figure 9 1 View Figure 1 ). There is a strong paracristid that joins a crestiform paraconid with a small lingual basin as in Pa. dolloi . The metaconid projects mesially, which, together with the protoconid, partly encloses a longitudinal valley almost as far as the paraconid ( Fig. 9E View Figure 9 1 View Figure 1 , E 3 View Figure 3 ), typical of most Paschatherium species , except Pa. marianae . It lacks the mesial convexity of this cusp in B. pellouini and B. phelizoni .
M 1–2: The paraconid forms only the lingual end of a strong paracristid ( Fig. 9E View Figure 9 1 View Figure 1 , E 3 View Figure 3 , F 1 View Figure 1 , F 3 View Figure 3 ). The trigonid is short, but well basined and its three cusps make an acute angle at the protoconid. In these ways it is like Pa. plaziati and Pa. marianae and different from the other Paschatherium species , where the paraconid is more median in position. The cristid obliqua joins the back of the trigonid slightly buccal of the midline. There is a marked ectoflexid. There is little retraction of the talonid compared to the trigonid, as in Pa. plaziati and Pa. marianae but unlike the others.
M 3: The talonid is less reduced than on most of the other Paschatherium species , but is like Pa. plaziati and Pa. marianae , although unlike these the hypoconulid does not project distally as far and the talonid cusps are less distinct from the encircling crest ( Fig. 9G, H View Figure 9 ).
Discussion: This is the largest species of Paschatherium and, being from the middle Ypresian Zone PEV site of Condé-en-Brie ( Hooker, 1996) and thus dating from c. 51–52 Mya, also the youngest.
| R |
Departamento de Geologia, Universidad de Chile |
| MNHN |
Museum National d'Histoire Naturelle |
| V |
Royal British Columbia Museum - Herbarium |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.