CADURCODONTINI, Wall, 1982

Veine-Tonizzo, Léa, Tissier, Jérémy, Bukhsianidze, Maia, Vasilyan, Davit & Becker, Damien, 2023, Cranial morphology and phylogenetic relationships of Amynodontidae Scott & Osborn, 1883 (Perissodactyla, Rhinocerotoidea), Comptes Rendus Palevol 22 (8), pp. 109-142 : 123

CADURCODONTINI

The tribe Cadurcodontini includes Zaisanamynodon , Amynodontopsis , Cadurcotherium and Cadurcodon . This clade is defined by five unambiguous synapomorphies (Bremer index = 1): the postglenoid process of squamosal is dihedron 42 (2); the upper premolars labial cingulum is always present 83 (0); the olecranon fossa of the humerus is low 193 (1); the mandibular condylar process is high 287 (0); the talonid of m3 is longer than the trigonid 288 (1).

Zaisanamynodon is placed as a sister group of the clade formed by Amynodontopsis , Cadurcotherium and Cadurcodon . The monophyly of Zaisanamynodon is supported by three synapomorphies (Bremer index = 1): the zygomatic process progressively diverges from the maxilla 37 (0); the lingual cingulum of the upper molars is usually absent 114 (2); the third posterior loph is present on P4 298 (1). ZSN-KKS-28-IPB is a sister group of Zaisanamynodon borisovi , which supports its identification (Bremer index = 1). Zaisanamynodon borisovi (sensu lato, = ZSN-KKS-28-IPB and Z. borisovi ) differs from Zaisanamynodon protheroi by a single autapomorphy: the paracone fold of M3 is weak 289 (1). Zaisanamynodon protheroi is defined by only one unambiguous autapomorphy: the lingual cingulum of the lower premolars is reduced 148 (0), but five other ambiguous autapomorphies might support the distinction of the two species.

Cadurcotherium and Amynodontopsis form a clade supported by three unambiguous synapomorphies (Bremer index = 1): the rostral end of the nasal bones is narrow 24 (0); the mandibular ramus is inclined posteriorly 60 (0); the labial cingulum of the lower molars is always absent 159 (3). Amynodontopsis is sister group to Cadurcotherium , and they share three synapomorphies (Bremer index = 2): the zygomatic process progressively diverges from the maxilla 37 (0); the presence of a sagittal crest on the basilar process 44 (1); the M3 paracone fold is weak 289 (1). Amynodontopsis jiyuanensis has six autapomorphies: nasal notch is above P1-3 3 (0); nasal bones are long 26 (0); paraoccipital process of the occipital is little developed 48 (1); upper molars antecrochet is usually present 110 (2); M1-2 metastyle is long 120 (1); M1-2 posterior part of the ectoloph is concave 122 (1). Cadurcotherium is supported by two synapomorphies (Bremer index = 2): the upper molars lingual cingulum is always absent 114 (3); the lower molars hypolophid is almost sagittal 161 (2). Cadurcotherium cayluxi is defined by two autapomorphies: the M1 postfossette is present 127 (0); the m3 talonid is equal or smaller than trigonid 288 (0). Cadurcotherium minum is defined by one autapomorphy: upper premolars labial cingulum is always absent 83 (3).

Cadurcodon is placed as a sister group to the clade formed by Cadurcotherium and Amynodontopsis . Cadurcodon is supported by six unambiguous synapomorphies (Bremer index = 2): the ramus coronoid process is little developed 61 (1); the I1 is absent 71 (1); the i1 is absent 76 (1); the upper molars antecrochet is usually absent 110 (1); the upper postcanine diastema is short 291 (1); the I3 size is distinctly smaller to I2 293 (2).