Protoclepsydrops

Protoclepsydrops; Temporal range: Upper Carboniferous (Middle Pennsylvanian)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
(unranked):	Amniota
Class:	?Synapsida
Order:	?Pelycosauria
Family:	?Ophiacodontidae
Genus:	Protoclepsydrops
Species:	P. haplous
Binomial name
	Protoclepsydrops haplous; Carroll, 1964

Protoclepsydrops was an early amniote from about 314 million years ago. Its remains were found at the Joggins Fossil Cliffs World Heritage Site. The dating of this site has been debated, with dates from 320 million years ago (mya) to 305 mya being suggested.^[1]^p39 It is now settled as 314.5–313.4 mya +/- 1.1 million years.^[1]^p40

The skeletal remains of Protoclepsydrops suggest it may have been a synapsid. If so, it is the oldest synapsid known, though its status is unconfirmed because its remains were fragmentary.^[1] Protoclepsydrops lived slightly earlier than Archaeothyris, which was definitely a synapsid. Like Archaeothyris, Protoclepsydrops had a body shape which resembled modern lizards.

References

↑ ^1.0 ^1.1 ^1.2 Benton M.J. and Donoghue P.C.J. 2006. Palaeontological evidence to date the tree of life. Molecular biology and evolution. 24(1): 26–53. [1]

[B.26D-1] 1.0 ^1.1 ^1.2 Benton M.J. and Donoghue P.C.J. 2006. Palaeontological evidence to date the tree of life. Molecular biology and evolution. 24(1): 26–53. [1]

[1]