Conoryctes comma (originally Hexadon molestus, Cope 1881; Schoch 1986; Paleocene; AMNH 3395). Here the Schoch drawings were not a great match for the fossil data. This taxon nests with the much earlier, Early Cretaceous marsupial, Vincelestes (Fig. 4). These were derived from Huerfanodon (Fig. 5). Note the elevated premaxila, flattened molars and deep dentary. The Schoch 1986 diagnosis of this genus is based on dental traits. He also compared Conoryctes to Huerfanodon, a related taxon in the LRT, but he also compared them to Onychonycteris, an unrelated, but convergent eutherian close to phenacodontids (Fig. 3), which is close to Conoryctella (Fig. 6) another putative taeniodont.
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Vincelestes neuquenianus (Bonaparte 1986, Early Cretaceous, 130 mya). Derived from a sister to Huerfanodon, Vincelestes is a carnivorous marsupial sister to the traditional taeniodont, Conoryctes. Note the hyper-enlarged canines and short rostrum. Premolars were not carnassial in shape, but still able to process by cutting and grinding. Nine individuals are known. Skeleton is probably a chimaera of several specimens and the degree of completion is unknown. The tail is extraordinarily long and provided with deep chevrons. Image from Digimorph.org and used with permission. Scale bar = 1 cm.
Huerfanodon torrejonius (Cope 1882; Eocene; AMNH 3224, Schoch 1986, USNM 15412) was traditionally considered a taeniodont, but here nests basal to the Vincelestes/ Thylacosmilus clade. Despite its late appearance, this taxon is more primitive than the others, which puts its genesis deep into the Jurassic. In dorsal view the skull is not compressed anterior to the jugals, similar to the ancestral Chironectes.
Cope ED 1881. On some Mammalia of the lowest Eocene beds of New Mexico. Palaeontological Bulletin 33:484-495.
Schoch RM 1986. Systematics, functional morphology and macroevolution of the extinct mammalian order Taeniodonta. Bulletin of the Peabody Museum of Natural History, Yale University, New Haven. 307pp.