Yindirtemys birgeri Bendukidze, 1993

Oliver, A & Daxner-Höck, G, 2017, Large-sized species of Ctenodactylidae from the Valley of Lakes (Mongolia): An update on dental morphology, biostratigraphy and paleobiogeography, Palaeontologia Electronica 20 (1), pp. 1-22 : 14-15

Yindirtemys birgeri Bendukidze, 1993 .

Figure 7.1-7.8 .

1993 Yindirtemys birgeri Bendukidze , p. 64-65, 143.

1997 Yindirtemys sajakensis birgeri Bendukidze , p. 207.

2004 Yindirtemys birgeri Lopatin , p. 292-293.

2009 Yindirtemys birgeri Benduzidze, de Bruijn, and Van den Hoek Ostende , p. 351-352, 356, 368- 369.

Holotype. Palate with P4-M3 left and P4-M3 right.

Bendukidze (1993: pl. XXI, fig. 2).

Type Locality. Altyn Schokysu (Aral region, Kazakhstan).

Material and Measurements. Tatal Gol (TAT-051/ 2) NHMW 2012/0060/0001. Palate with P4-M3 left and P4-M3 right. See Table 5 and Appendix 3.

Stratigraphic Range in Mongolia. Upper part of the late Oligocene, Mongolian biozone C1; Hsanda Gol Fm.

Geographic Distribution. Valley of Lakes ( Mongolia) and North Aral region ( Kazakhstan).

Description. P4. The labial posteroloph is short (one of two specimens) or medium (one of two). The lingual posteroloph is connected to the protocone (two out of two). The lingual crest of the metaloph is long and connected to the posteroloph (two out of two).

M2. The two specimens are heavily worn and many of their morphological characters not visible. The labial anteroloph is connected to the paracone. The lingual anteroloph is absent.

M3. The labial anteroloph is long and connected to the paracone (one of two specimens) or it is medium long (one of two). The lingual anteroloph and the anterior groove are absent. The protoloph is anterior and transversely directed to the protocone. One specimen bears a deflexus structure and the other a deflexus structure and an anticrochet. The sinus is transverse and deep. The metaloph is connected transversely to the hypocone. The tooth morphology is swollen and bulky.

Remarks. The complete maxilla from Mongolia is similar in size to Yindirtemys birgeri Bendukidze, 1993 and Y. ambiguus Wang, 1997 . However, both M3 from Mongolia have deflexus structure, and according to Wang, 1997, this structure is absent in Yindirtemys ambiguus . Tatal Gol ( Mongolia) is the easternmost occurrence of Yindirtemys birgeri . So far this species has only been recorded from the Aral Fm. in Kazakhstan.

Figures

FIGURE 7. Complete maxilla of Yindirtemys birgeri from the locality of Tatal Gol (TAT-051/2- NHMW 2012/0060/0001) in the Valley of Lakes (Mongolia). Nos. 1-8. 1) P4 left; 2) M1 left; 3) M2 left; 4) M3 left; 5) P4 right; 6) M1 right; 7) M2 right; 8) M3 right. All teeth same magnification. Scale bar equals 1 mm.