Biology 680Major Groups of Vertebrates 2009 - PelycosauriaDr. Stuart S. Sumida

The Close Relatives of Pelycosaurs

Advanced Amphibian: e.g. SeymouriamorphaSeymouria sanjuanensis

Seymouriamorphs are amphibians:Retain an intertemporal bone (amniotes have lost them)

Parareptilia

Am

niota?

Eureptilia

Am

niota

Diadectomorpha

Synapsida

Mesosauridae

Bolosauridae

Pareiasauridae

Procolophonoidea

Captorhinidae

Protorothyrididae

Diapsida

Sumida: Origin of Amniotes, Fig. 1.

Diadectes

Orobates pabsti(Diadectomorph)

1 cm

Orobates pabsti (Diadectomorph)

Diadectomorpha:

•No intertemporal bone like other amniotes

•Feature of first and second vertebrae

•Very terrestrially adapted

Diadectomorpha:•No intertemporal bone like other amniotes•Feature of first and second vertebrae•Very terrestrially adapted

Diadectomorpha:

•No intertemporal bone like other amniotes

•Feature of first and second vertebrae

•Very terrestrially adapted

Parareptilia

Am

niota?

Eureptilia

Am

niota

Diadectomorpha

Synapsida

Mesosauridae

Bolosauridae

Pareiasauridae

Procolophonoidea

Captorhinidae

Protorothyrididae

Diapsida

Sumida: Origin of Amniotes, Fig. 1.

PARAREPTILIA Includes:

•Mesosauria•Bolosauridae•Procolophonia•Paraiesauria

Mesosaurus: A member of Mesosauria

Eudibamus reconstruction

Bradysaurus: A member of the Parieasauria

Parieasaurs have lumpy, bumpy skulls

Scutosaurus

Parareptilia

Am

niota?

Eureptilia

Am

niota

Diadectomorpha

Synapsida

Mesosauridae

Bolosauridae

Pareiasauridae

Procolophonoidea

Captorhinidae

Protorothyrididae

Diapsida

Sumida: Origin of Amniotes, Fig. 1.

Basal Captorhinid: Eocaptorhinus

Development of Large Size in Captorhinidae

At least twice.

1 cm

New taxon: (Albright, in prep) New, miniature, captorhinid with three rows of dentary and maxillary teeth.

1 cm

New taxon

Size Range in Captorhinid Reptiles

(All specimens collected by Everett C. Olson.)

1 cm

Parareptilia

Am

niota?

Eureptilia

Am

niota

Diadectomorpha

Synapsida

Mesosauridae

Bolosauridae

Pareiasauridae

Procolophonoidea

Captorhinidae

Protorothyrididae

Diapsida

Sumida: Origin of Amniotes, Fig. 1.

Basal Synapsida (“Pelycosauria”): A single opening on side of skull

an – angularart – articularbps – basiparasphenoidca – anterior coranoidco - coranoidd – dentaryec – ectopterygoideo - exoccipitalf – frontalj – jugall - lacrimalm - maxillan – nasalp – parietalpal - palatinepf – postfrontalpm – premaxillap - postparietalpra - prearticularprf – prefontalpt - pterygoidq – quadrateqj - quadratojugalsa – surangularsm – septomaxillaso – supraoccipitalsp - splenialsq – squamosalsta – stapesv - vomer

Eothyridid pleycosaurs

Oedaleops

Eothyris

an – angularart – articularbps – basiparasphenoidca – anterior coranoidco - coranoidd – dentaryec – ectopterygoideo - exoccipitalf – frontalj – jugall - lacrimalm - maxillan – nasalp – parietalpal - palatinepf – postfrontalpm – premaxillap - postparietalpra - prearticularprf – prefontalpt - pterygoidq – quadrateqj - quadratojugalsa – surangularsm – septomaxillaso – supraoccipitalsp - splenialsq – squamosalsta – stapesv - vomer

Haptodus

an – angularart – articularbps – basiparasphenoidca – anterior coranoidco - coranoidd – dentaryec – ectopterygoideo - exoccipitalf – frontalj – jugall - lacrimalm - maxillan – nasalp – parietalpal - palatinepf – postfrontalpm – premaxillap - postparietalpra - prearticularprf – prefontalpt - pterygoidq – quadrateqj - quadratojugalsa – surangularsm – septomaxillaso – supraoccipitalsp - splenialsq – squamosalsta – stapesv - vomer

Dimetrodon

an – angularart – articularbps – basiparasphenoidca – anterior coranoidco - coranoidd – dentaryec – ectopterygoideo - exoccipitalf – frontalj – jugall - lacrimalm - maxillan – nasalp – parietalpal - palatinepf – postfrontalpm – premaxillap - postparietalpra - prearticularprf – prefontalpt - pterygoidq – quadrateqj - quadratojugalsa – surangularsm – septomaxillaso – supraoccipitalsp - splenialsq – squamosalsta – stapesv - vomer