Fig 1.
Geographic map of the zokor fossil site, loc. ZD1001 (star), in Zanda Basin, southwestern Tibetan Plateau.
Black solid line, national highway; Dashed line, country road; Grey line, river; Circles: County seat and villages.
Fig 2.
Molars of Prosiphneus eriksoni from loc. ZD1001, Zanda, Tibet.
A. right M1, V 18032.2; B. right M2, V 18032.3; C. right M2, V 18032.6; D. right M2, V 18032.7; E. left M3, V 18032.10; F. left M3, V 18032.11; G. left m1, V 18032.13; H, left m1, V 18032.14; I, left m1, V 18032.15; J. right m1, V 18032.17; K. left m2, V 18032.19; L. left m2, V 18032.20; M. left m3, V 18032.25. A1-M1, occlusal view; A2-F2, labial view, G2-M2, lingual view, showing the dentine tracts.
Table 1.
Tooth measurements (maximum length and width of the wear surface) of Prosiphneus eriksoni from loc. ZD1001, Zanda Basin, Tibetan Plateau (mm).
Table 2.
Dentine tract measurements of molars of Prosiphneus eriksoni from loc. ZD1001, Zanda Basin, Tibetan Plateau (mm).
Fig 3.
Scatter diagram of the measurements of M1 (left) and m1 (right) of Prosiphneus and “Pliosiphneus” lyratus.
a, Prosiphneus cf. P. eriksoni, Zanda, Tibet; b, P. qiui, Amuwusu, Nei Mongol; c, P. haoi, Qin’an, Gansu; d, P. licenti, Qin’an, Gansu; e, P. tianzuensis, Tianzhu, Gansu; f, Prosiphneus cf. P. eriksoni, Kunlun Pass, Qinghai; g, P. licenti, Qingyang, Gansu; h, P. murinus, Yushe, Shanxi; i, “Pliosiphneus” lyratus, Yushe; j, Prosiphneus cf. P. eriksoni, Bilike, Nei Mongol; k, P. eriksoni, Ertemte, Nei Mongol.
Fig 4.
Comparison of the dentine tract measurements of M1 (right) and m1 (left) of Prosiphneus.
1, P. qiui, Amuwusu; 2, P. haoi, Qin’an; 3, P. licenti, Qingyang; 4, P. murinus, Yushe; 5, P. tianzuensis, Tianzhu; 6and 8 P. eriksoni, 6, Ertemte; 8, Zanda; 7and 9, Prosiphneus cf. P. eriksoni: 7, Bilike; 9, Kunlun Pass. 1–6, data cited from Zheng et al. (2004: Tables 1 and 2); 7, remeasured and 8, 9 measured by authors.
Table 3.
Data matrix employed in the cladistic analysis, including 13 taxa and 55 characters.
A question mark means that the information is not available. Part 1, characters 1–18.
Table 4.
Data matrix employed in the cladistic analysis, including 13 taxa and 55 characters.
A question mark means that the information is not available. Part 2, characters 19–36.
Table 5.
Data matrix employed in the cladistic analysis, including 13 taxa and 55 characters.
A question mark means that the information is not available. Part 3, characters 37–54.
Fig 5.
Strict consensus tree (L = 122; CI = 0.869; RI = 0.888) based on the dental character matrix in Table 3, showing the relationships of Prosiphneus and relevant taxa.
Fig 6.
Species ranges and cladistic phylogeny among the Prosiphneus in the Neogene China.
Most of the species ranges are approximate. The first lower molars are scaled to their approximate relative size and the Fig also shows the m1 evolutionary trends of Prosiphneus especially on the heightening of the crown and lateral dentine tracts.
Fig 7.
Geographic distribution of the main localities of the fossil and extant zokors.
Green line–extant (referred from website of IUCN, http://www.iucnredlist.org/details/14116/0, /14118/0, /14119/0, /14120/0, /14121/0, and /14122/0, accessed on Dec. 11th, 2014); yellow shadow and black circles–fossils (based on Zheng, 1994). Red arrow shows a potential dispersal way of the Prosipheus from its center of origin in north China and Mongolian Plateau to the Zanda Basin of southwestern Tibetan Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet.