Dsungarodon, Pfretzschner & Martin, 2005

Pfretzschner, Hans-Ulrich, Martin, Thomas, Maisch, Michael W., Matzke, Andreas T. & Sun, Ge, 2005, A new docodont mammal from the Late Jurassic of the Junggar Basin in Northwest China, Acta Palaeontologica Polonica 50 (4), pp. 799-808 : 800-802

Genus Dsungarodon nov. Pfretzschner and Martin Derivation of the name: Named after the Junggar Basin (formerly Dsungar) and OÔO v, stem of OÔOÓÇ (Greek) tooth. Dsungarodon (masculine), tooth from the Junggar Basin.

Type species: Dsungarodon zuoi sp. nov.

Diagnosis.—Upper molar characters: (1) cusp X hook shaped and recurved buccally; (2) basin developed between cusps A−C−Y−X; (3) cusps A and C high and slender and considerably higher than cusps X and Y; (4) buccal crests forming a cutting edge; (5) lingual portion mesial to the A−X−crest is reduced; (6) distal margin C−Y of the lingual portion of the tooth not deeply indented; (7) strong ectoflexus; (8) outline of the tooth crown triangular.

Lower molar primitive (–) and derived (+) characters: (1) cusp e and f reduced (+); (2) crest b−e well developed (–); (3) crest b−e protruding to the mesial end of the tooth (+); (4) crest e−g missing (–); (5) crest b−g well developed (–); (6) enlarged anterior basin (pseudotalonid) (+); (7) cusp g enlarged, similar in height to cusp c (+); (8) region distal to cusps a and c reduced (+).

Differential diagnosis.—The upper molar of the new taxon differs from those of Haldanodon exspectatus by the following characters: (1) cusp X hook−shaped and recurved buccally; (2) basin developed between cusps A−C−Y−X; (3) cusps A and C high and slender; (4) buccal crests forming a cutting edge; (5) lingual portion mesial to the A−X−crest reduced; (6) distal margin C−Y of the lingual portion of the tooth not deeply indented; (7) strong ectoflexus. Dsungarodon differs from Simpsonodon oxfordensis by the following upper molar characters: (1) buccal cusps A and C much more slender and considerably higher than cusps X and Y; (2) lingual part of the tooth more narrow and more constricted; (3) outline of the tooth crown more triangular.

At the lower molars, the new taxon differs from Tegotherium , Sibirotherium , and Tashkumyrodon by exclusion of

PFRETZSCHNER ET AL.— NEW JURASSIC DOCODONT FROM CHINA 801

1 mm

cusp e from the border of the “pseudotalonid” and by retaining a well developed crest b−g. From Docodon , Haldanodon , and Borelalestes it differs by reduction of cusps f, presence of a large anterior basin (“pseudotalonid”), reduction of a c−d crest, large cusp b, and cusps c and g being of equal height. From Simpsonodon it differs by a straight, mesio−lingually oriented crest b−e that is accompanied by a straight transversal valley between the crests b−g and b−e. Furthermore, the pattern of enamel ridges in the region distal to cusp a and c is less complex. Dsungarodon is clearly distinct from Krusatodon by the following characters: (1) crest b−e runs straight forward in a mesio−lingual direction; (2) a distinct cusp e is not developed; (3) crest b−g is straight and not S−shaped; (4) cusp g does not bulge more lingually than cusp c; (5) crest c−d is almost straight; (6) a distinct cusp f is not developed.

Distribution and stratigraphical range.—Upper part of Qigu Formation at Liuhuanggou, 40 km southwest of Urumqi in the Junggar Basin (Xinjiang Autonomous Region, NW China). Early Late Jurassic (Oxfordian).