Eoelfomys lapradensis, Vianey-Liaud & Hautier, 2022
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publication ID |
https://doi.org/10.1186/s13358-022-00245-3 |
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persistent identifier |
https://treatment.plazi.org/id/497F1B1D-FFEB-DF67-C483-4172FB95FA79 |
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treatment provided by |
Felipe |
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scientific name |
Eoelfomys lapradensis |
| status |
nov. gen. |
Eoelfomys lapradensis nov. gen. nov. sp.
Elfomys nov. sp. Hartenberger, in Sudre et al., 1990, p. 20.
Elfomys sp. in Comte et al., 2012: Fig. 17 View Fig ; Pl.8, Fig. x to z
Holotype. LAP 243 , unworn right upper M1. ( Fig. 53c View Fig ).
Diagnosis. Size close to that of the large Elfomys engesseri Hooker & Weidmann, 2007 ; smaller than E. catalaunicus Bonilla-Salomon et al., 2016 .
Differs from the Eocene Elfomys species in:
- Te occurrence of a strong and high endoloph, which prevents the communication between the sinus and the mesoflexus;
- Te absence of connection between the metalophule II and the posteroloph on the upper teeth, the absence of a long prehypocrista connecting a mesiobuccal metaconule crest, the presence of a strong metaconule;
- Te occurrence of a long low mesolophid on m2–m3.
Material and measurements. Appendix, S3: two M1, one M2, one m2, one m3. (cf. Figure 17 View Fig , in Comte et al., 2012). Teir size is close to that of Elfomys engesseri Hooker & Weidmann, 2007 , and larger than E. catalaunicus Bonilla-Salomon et al., 2016 .
Description. Te crowns are unilaterally hypsodont but low.
M1–2. Te parastyle of the two M1 is slightly curved towards the paracone. LAP 243 , the holotype ( Fig. 53c View Fig ), shows a premetacrista, not easily distinguishable on the other two upper molars ( LAP 244 and 245), which are worn. Te posterior area is narrower on the M2 ( LAP 244 ) than on the M1 ( LAP 243 , 245 ) . Te three teeth have a high endoloph separating the shallow sinus from the mesoflexus. Te paraconule stretches forward and protrudes mesially. Te attachment of the protoloph to the mid-protocone is weak. Te mesostyle is present. Te mesoloph either reaches the buccal flank of the metaconule ( LAP 245 : Fig. 53d View Fig ), or is shorter ( LAP 244 : Fig. 53e View Fig ) or replaced by a low ridge reaching the buccal base of the metaconule ( LAP 243 ) . On the latter, a very low short ridge is reminiscent of a vestigial metalophule I. Te metalophule II is short and weakly connected to the base of the metaconule. Te latter also weakly attaches to the mid-hypocone. Tere are scarce granules on the enamel surface .
Te main differences with the late Eocene species of Elfomys are the strong endoloph together with the absence of communication between the sinus and the mesoflexus, the absence of relationship of the metalophule II with the posteroloph, the absence of a long prehypocrista connecting to the mesiobuccal metaconule crest.
m2-3. Te teeth are flatter than that of the late Eocene Elfomys , the metaconid less salient, the anteroconid smaller.
On m2 (LAP 242; Fig. 53f View Fig ), the anterolophid is very short, the anteroflexid reduced, and the anterocingulid absent. Te two parts of the metalophulid I are continuous, even if their extremities are not completely fused. Te long and oblique postprotocristid makes an angle with the short mesiodistal ectolophid. From the junction between the postprotocristid and the ectolophid, a few low granules punctuate the path of a mesolophid. Te mesoconid is weak. Te entolophid is straight and connects the junction of the prehypocristid to the ectolophid. Te sinusid and mesoflexid do not communicate.
On m3 ( Fig. 53g View Fig ), the anterolophid is a little longer and it is weakly attached to the short lingual part of the metalophulid I. Te buccal part of the metalophulid I is free and distally oriented. Small and very low granules trace the mesolophid path. Te posterior lobe is reduced.
Remarks and comparisons
As for basal Teridomorpha and the middle Eocene species of Masillamys or Protadelomys , this genus displays a high endoloph. Eoelfomys could represent an early stage preceeding Elfomys , genus in which the endoloph disappears, the prehypocrista lengthens to the mesoloph, and the distal ectolophid reduces. Te size and morphology of its lower molars is similar to those of the mandible Ek H003 from Egerkingen.
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