sinonyx

“Chinese Claw”

Species: Sinonyx jiashanensis

Time Period: Paleocene (60 MYA)

Location: Anhui province, People’s Republic of China

Sinonyx face reconstruction

 
Discovered by Philip Gingerich, director and curator of the Paleontology Museum at the University of Michigan , Sinonyx was an early primitive from of Mesonychid. The most significant feature of this genus is the skull, which is large in proportion to the body. This large skull, with its extended occipital bone and large sagital crest contained a tiny brain.

Sinonyx skeleton


Cast of Sinonyx skeleton, located at the Exhibit Museum of Natural History at the University of Michigan

Sinonyx skull

Side view of the skull of Sinonyx, showing the large sagital crest.

 Sinonyx was a creature about the size of a modern wolf built for stamina and strength, and it is believed to have hunted or scavenged along sea shores. The large sagital crest indicates a powerful bite, for these are the bones which anchor muscle to the lower jaw or mandible; with the increased surface area indicating a large muscle mass. The elongated muzzle and tooth shape of Sinonyx are atypical when compared to other Mesonychids, so it is believed this particular genus was developing features closer to that of the cetaceans (whales and dolphins), and it is a land animal similar to this from which whales are derived.

 

Sources: "Medical Illustrator Makes Puzzle Pieces Fit" by Joanne Nesbit, The University Record, March 25, 1997
"The Origins of Whales and the Power of Independent Evidence" by Raymond Sutera, in 'Reports of the National Center for Science Education', 2001

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