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Gobiconodon (Early Cretaceous mammal) revised
A new online paper:
Alexey Lopatin & Alexander Averianov (2014)
Gobiconodon (Mammalia) from the Early Cretaceous of Mongolia and
Revision of Gobiconodontidae.
Journal of Mammalian Evolution (advance online publication)
There are two species of Gobiconodon in the Early Cretaceous Khoboor
locality of Mongolia: G. borissiaki Trofimov, 1978, and G. hoburensis
(Trofimov, 1978). The smaller G. hoburensis has i2 half the size of
i1, double-rooted dp2, and two generations of molariforms (m1-5 and
m1r-4r). In the larger G. borissiaki, i2 is about ¾ size of i1, dp2 is
single-rooted, and there are three generations of molariforms (m1-5,
m1r-5r, m1rr-2rr). In larger G. ostromi Jenkins and Schaff, 1988,
there are three molariforms of the third generation (m1rr-3rr). The
anterior lower dentition of Gobiconodon is interpreted as i1-3, c, and
dp1-2. The replacement of dp1 by p1 is known only in G. hoburensis.
The dp2 is not replaced and may be lost in some specimens (G.
hoburensis, G. ostromi) with its alveolus plugged by bone. Gobiconodon
includes five valid species: G. borissiaki, G. hoburensis, G. ostromi,
G. hopsoni Rougier et al., 2001, and G. zofiae Li et al., 2001 (=G.
luoianus Yuan et al., 2009, syn. nov.). The holotype upper maxilla of
G. hopsoni is not diagnostic and a new diagnosis for this species is
provided based on lower dentitions from the type locality. Repenomamus
Li et al., 2001, and Meemannodon Meng et al., 2005, are the only other
members of the Gobiconodontidae. The dental formula of Repenomamus is
reinterpreted as I1-3, C, P1, M1-5/i1-2, c, p1-2, m1-5 and thus it
differs from Gobiconodon by lack of i3 and P2. Meemannodon is
different from Gobiconodon by lack of i3 (the upper dentition is
unknown). The Early Cretaceous Jeholodens, Yanoconodon, and
Liaoconodon are closer to the Gobiconodontidae than to the
Amphilestidae by having only two premolars. Liaoconodon with modified
anterior dentition is likely the closest relative to the
Gobiconodontidae. The Gobiconodontidae is likely the sister taxon for
the clade Amphilestidae + Trechnotheria.