Plesiosminthus winistoerferi Engesser, 1987

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 : 13-15

Plesiosminthus winistoerferi Engesser, 1987

Type locality. Brochene Fluh 53, MP30, Switzerland.

Holotype. m2 sin., Br.F. 1, Naturhistorisches Museum Basel.

Material and measurements. Appendix 1.

Diagnosis. From Engesser (1987). "Very large species of Plesiosminthus with very long and strong posterior arm of protoconid on m2 and m3, double protoloph on M2 and M3, and little reduced m3/M3. m1 always with secondary ridge between metalophid and mesolophid. Entoloph of M2 situated far lingually, ectolophid of m2 and m3 far labially. Connection between protoconid and anterior cingulum of m2 and m3 sometimes interrupted. m2

PALAEO- ELECTRONICA.ORG equally wide as m1, but somewhat longer. Upper molars with 3 roots. Upper incisor with longitudinal groove."

It is generally assumed ( Schaub, 1930; Ziegler and Werner, 1994; Engesser, 1987) that the evolutionary trend of the protoconid hind arm of Plesiosminthus is to lose contact with the metaconid, become shorter, and finally disappear. Apparently, this is not the case in P. winistoerferi , where the pcdha may even reach the molar border, a feature unknown in other species of the genus. It is doubtlessly the largest species known, but the length relation between m2 and m1 may be misleading due to the small number of specimens (see section "Size").