'''Zhangheotherium''' is a
genus of
symmetrodont, an extinct
order of
mammals. Previously known from only the tall pointed crowned teeth, ''Zhangheotherium'', described from
Liaoning Province,
China,
fossils in
1997, is the first symmetrodont known from a complete skeleton. It was dated to between 145-125 million years ago in the
Cretaceous. A single
species, '''Zhangheotherium quinquecuspidens''', is presently known.
Symmetrodonts and other archaic mammals such as
multituberculates and
monotremes are still being debated on their taxonomical relationships. ''Zhangheotherium'' has many primitive characteristics. Among them is a venomous spur at the foot, seen today in the modern
platypus. In addition, it walked with a reptilian sprawl, not at all like our known mammals but instead like many
Mesozoic mammals, like ''
Jeholodens'' and ''
Repenomamus''.
The specimen
GMV 2124 of the feathered dinosaur ''
Sinosauropteryx prima'' contained 2 jaws of ''Zhangheotherium'' in its stomach region (Hurum ''et al.'' 2006). Thus, it seems to have preyed on this primitive mammal, possibly on a regular basis.
References
★ Hurum, Jørn H.; Luo, Zhe-Xi & Kielan-Jaworowska, Zofia (2006): Were mammals originally venomous? ''Acta Palaeontologica Polonica'' '51'(1): 1–11.
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