Plesiosminthus sp.

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 : 15-16

Plesiosminthus sp. small size

Apart from the species described above, a very small Plesiosminthus is documented in a number of localities:

Mirambueno 2A, MP27, Spain. M1 sup.dext., 0.85 x 0.74, RGM 558568, M2 sup.dext., 0.81 x 0.81, MIR2A 110; in our material there is a clear gap between these specimens and the distribution of P. margaritae n. sp. (see Figure 6 ).

Ruisseau du Bey, MP28, Switzerland. Specimens of similar size have been reported from Ruisseau du Bey ( Engesser, 1987; one M2 and maybe one M1); Engesser (1987) attributed this material to P. promyarion , but the size range of his sample is very large, and the small specimens probably represent another species.

Canales, MP28, Spain. The size of these specimens (three M1 and one M2) is at the lower limit of the penecontemporaneous sample from VIV1. It must, however, represent another species, because one M2 has a short mesoloph, and another one has a posterior metalophule plus an interrupted anterior connection. (see Alvarez et al. 1999).

Herrlingen 8, MP28, Germany. Two m2 from Herrlingen 8 are smaller than P. conjunctus from the same locality. They lack the protoconid hind arm and have a less-developed mesolophid (see Ziegler 1994).

FREUDENTHAL & MARTÍN-SUÁREZ: EUROPEAN PLESIOSMINTHUS

Thézels, MP30, France. Comte (2000) reported two very small M2 from Thézels as P. admyarion or Plesiosminthus sp. ?.

The presence of Plesiosminthus in Mirambueno 4C and 4D (MIR4C and MIR4D), Mp26, Spain, is doubtful; no molars have been found, only several incisor fragments with the characteristic furrow. If they represent Plesiosminthus , it must be a large species. The incisors of some Gliridae present a similar furrow, but in that group the furrow is less developed ( Freudenthal, 1997).

Figures

FIGURE 6. Scatter diagrams of molar length (L) and width (W) of Plesiosminthus aff. conjunctus (cross) and Plesiosminthus sp. (circle) from Mirambueno 2A, compared with the distribution area (rectangle) of Plesiosminthus conjunctus molars from HERR8 (in mm). 1, m1; 2, m2; 3, m3; 4, M1; 5, M2; and 6, M3.