Name: Angelosaurus ‭(‬San Angelo lizard‭)‬.
Phonetic: An-gel-o-sore-us.
Named By: E.‭ ‬C.‭ ‬Olsen‭ & ‬J.‭ ‬R.‭ ‬Beerbower‭ ‬-‭ ‬1953.
Classification: Chordata,‭ ‬Synapsida,‭ ‬Pelycosauria,‭ ‬Caseidae.
Species: A.‭ ‬dolani‭ (‬type‭)‬,‭ ‬A.‭ ‬greeni,‭ ‬A.‭ ‬romeri.
Diet: Herbivore.
Size: A.‭ ‬dolani‭ ‬3‭ ‬-‭ ‬3.5‭ ‬meters long.‭ ‬A.‭ ‬greeni‭ ‬4‭ ‬meters long.‭ ‬A.‭ ‬romeri‭ ‬2.5‭ ‬meters long.
Known locations: USA,‭ ‬Oklahoma‭ & ‬Texas.
Time period: Kungurian to Wordian of the Permian.
Fossil representation: Remains of several partially preserved individuals.

       A heavily built pelycosaur similar to Cotylorhynchus,‭ ‬Angelosaurus also shared its habitat with Caseopsis and Caseoides,‭ ‬all caseidids typified by the type genus of the group,‭ ‬Casea.‭ ‬These were a distinctive group of pelycosaurs that don’t seem to have been that specially adapted beyond being quadrupedal and having large round bodies that are often described as being barrel-like.‭ ‬Herbivores like these seem to have been quite common at this time,‭ ‬and were likely one of the principal prey types of predatory pelycosaurs like the sail backed Dimetrodon.
       Angelosaurus species came in a range of sizes with A.‭ ‬greeni being the‭ ‬largest at four meters and A.‭ ‬romeri the smallest at‭ ‬2.5‭ ‬meters.‭ ‬The type species A.‭ ‬dolani is roughly intermediate between these two in terms of size.‭ ‬The oldest species of Angelosaurus are A.‭ ‬dolani and A.‭ ‬greeni‭ (‬Kungurian-Roadian‭)‬,‭ ‬while A.‭ ‬romeri seems to have existed slightly later in the Permian‭ (‬Roadian-Wordian‭)‬.‭ ‬This may indicate that as time went on the Angelosaurus genus evolved to become physically smaller.

Further reading
-‭ ‬The San Angelo Formation,‭ ‬Permian of Texas,‭ ‬and its Vertebrates,‭ ‬E.‭ ‬C.‭ ‬Olsen‭ & ‬J.‭ ‬R.‭ ‬Beerbower‭ ‬-‭ ‬1953.
-‭ ‬Permian vertebrates from Oklahoma and Texas.‭ ‬Part I.‭—‬Vertebrates from the Flowerpot Formation,‭ ‬Permian of Oklahoma,‭ ‬E.‭ ‬C.‭ ‬Olsen‭ & ‬H.‭ ‬Barghusen‭ ‬-‭ ‬1962.


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