What is Protoclepsydrops?
{{italictitle}} {{Taxobox | colour = | name = ''Protoclepsydrops'' | fossil_range = [[Upper Carboniferous]] (Middle [[Pennsylvanian]]) | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | unranked_classis = [[Amniota]] | classis = ?[[Synapsid]]a | ordo = ?[[Pelycosauria]] | familia = ?[[Ophiacodontidae]] | genus = '''''Protoclepsydrops''''' | species = '''''P. haplous''''' | binomial = ''Protoclepsydrops haplous'' | binomial_authority = [[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.<ref name=B&D>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. [http://mbe.oxfordjournals.org/content/24/1/26.full.pdf+html]</ref><sup>p39</sup> It is now settled as 314.5–313.4 mya +/- 1.1 million years.<ref name=B&D/><sup>p40</sup> The [[Skeleton|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.<ref name=B&D/> ''Protoclepsydrops'' lived slightly earlier than ''[[Archaeothyris]]'', which was definitely a synapsid. Like ''Archaeothyris'', ''Protoclepsydrops'' had a body shape which resembled modern [[lizard]]s. == References == {{Reflist}} {{biology-stub}} [[Category:Stem tetrapods]]