Plesiosminthus admyarion Comte, 2000

Freudenthal, Matthijs & Martín-Suárez, Elvira, 2017, A revision of European Plesiosminthus (Rodentia, Dipodidae), and new material from the upper Oligocene of Teruel (Spain), Palaeontologia Electronica 9 (1), pp. 1-25 : 12

Plesiosminthus admyarion Comte, 2000

Type locality. Thézels, MP30, France.

Holotype. m2 dext., Th. 7582, coll. University Poitiers.

Material and measurements. See Appendix 1.

Diagnosis. Translated from Comte (2000). Dimensions similar to those of the type material of P. schaubi , and sharing a number of morphological features with that species, but the relative proportions of the teeth and several other characters show affinities with P. myarion .

According to its author, P. admyarion Comte, 2000 is significantly different from P. schaubi from Coderet in terms of size: its m1, m3, and M3 are significantly longer, its M1, M2, and m2 are significantly shorter. The t-test values reported by Comte are somewhat different from our results (see Table 4 ) because that author applied the formula for equal variances (Vianey-Liaud, personal commun., 2016), but we confirm the differences are significant at α = 0.05. However, the distributions of the measurements ( Figures 7-12 ) largely overlap and size can hardly serve to distinguish these species.

The MV values are very similar: very high values for m2 and the lowest values of all species for M2. Plesiosminthus admyarion and P. schaubi are probably closely related. Among the differences is the more reduced m3 of P. schaubi (maximum four lingual crests). Another difference is found in the anteroconid of m1: isolated (n = 39), connected to the metaconid (30), or to the protoconid (39); in Coderet it is rarely isolated, generally connected to the metaconid, never to the protoconid.

Figures

FIGURE 7. m1 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 8. m2 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 9. m3 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 10. M1 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 11. M2 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.

FIGURE 12. M3 length (1) and width (2) of Plesiosminthus species. The bars represent the minimum and maximum in mm, a tick marks the mean, and the number of specimens is given to the right.