[MM] Gobiconodon borissiaki
DESCRIBER Trofimov, 1978
TIME Cretaceous Early
Valanginian Hauterivian Barremian Aptian Albian
FOSSILSITE Cannonball Member, Oshih Formation, Mongolia; Khoobur, Mongolia; Shestakovo, Ilek Formation, Kemerovo Region,Siberia, Russia
Gobiconodon borissiaki (Trofimov, 1978) > Gobiconodon hoburensis (Trofimov, 1978 )[ >> Guchinodon hoburensis (Trofimov, 1978 )] > Gobiconodon hopsoni (Rougier, Novacek, McKenna and Wible, 2001) > Gobiconodon ostromi (Jenkins and Schaff, 1988) > Gobiconodon zofiae (Li, Wang, Hu & Meng, 2003) > Gobiconodon sp. (1) (Rougier, Novacek, McKenna & Wible, 2001) > Gobiconodon sp. (2) (Tang et al., 2001) > Gobiconodon sp. (3) (Cuenca-Bescós & Canudo, 2003 )
Type species: Gobiconodon borissiaki Trofimov, 1978.
Emended generic diagnosis: Small to medium-sized triconodonts, with large procumbent i1 and correspondingly enlarged I1; reduction of number of incisors to 1 or 2; conic and pointed posterior incisors, canines, and anterior premolariforms. Anterior premolariforms (p1-p3) with tall central cusp and crown height greater than mesiodistal measurement. Accessory cusp on these premolariforms very small to absent. Procumbent i-p1. Rounded muscular depression on medial aspect of lower jaw, anteroventral to mandibular foramen (fig. 4; Kielan-Jaworowska and Dashzeveg, 1998: fig. 6c). Separate infraorbital canals connecting orbit with rostrum (see below). Anterior molariform teeth undergo replacement (documented in Gobiconodon ostromi, and probable in the remaining Gobiconodon species); this feature, however, may be plesiomorphic and not diagnostic. Rounded fossa in the base of the lesser trochanter of the femur and heavier appendicular skeleton (larger cross-section diameter) than other Mesozoic and basal tribosphenic mammals.
Much of the skeleton is known and several complete skulls have been collected (not yet described)
The specimen (PIN N 3101/09), collected in the Ilek Svita and dated as Neocomian (Osyko, 1958), or Aptian– Albian (Rozhdestvensky, 1960), is rather poor, but it has been identified as Gobiconodon borissiaki.