Movatterモバイル変換

Archosauromorpha

Protorosaurs

Taxa on This Page

1. Archosauromorpha
2. Czatkowiella X
3. "Protorosauridae" X
4. Protorosaurus X

Life restoration ofProlacerta broomi, an archosauromorph from theInduan of South-westGondwana. Length about 60 cm.Protorosaurus speneri would have been very similar in appearance. The long neck and long hind limbs (for bursts of bipedal running) represent the basal or primitive archosauromorph condition, from which the various more specialised types evolved. Illustration by Ghedoghedo (Wikimedia)

Descriptions

Archosauromorpha: Buzzards > Lizzards

Links:The Triassic Takeover with numerous links);Reptilian Systematics.Archosauromorpha - Wikipedia, the free encyclopedia has a short discussion, outlining the enormous scope of this group.Archosauromorphahas a similar, somewhat fuller discussion, in the same vein, in Spanish. You can get a sense of this diversity directly atMikko's Phylogeny or on theTaxonomicon. There is also an on-line (no figures) version of Chris Brochu's review of archosaur systematics and phylogenetic problems at  Journal of Paleontology- Progress and future directions in ... .  Several sites discuss Archosauromorpha as background to the study of dinosaurs; for exampleDinosaur Origins.Comparative Anatomy Topic 3 - Archosaurs andArchosauria- More on Morphology  have introductions to the anatomy of the group.  Some of John Hutchinson's archosaur mechanics papers (destined to be classics) can found here and there, includinghere. ATW051001. (phylogeny MAK101007)

Protorosauridae: (= Archosauromorpha?)Protorosaurus, Czatkowiella.

Comments: Although cladograms byBorsuk-Białynicka & Evans, 2009 uniteProtorosaurus andCzatkowiella, there are few, if any, clear synapomorphies (unique shared features that define a clade as having a common ancestor apart from other related forms) and this is probably a paraphyletic group. MAK101007

Protorosaurus speneri. From Henry Alleyne Nicholson, 1876,The Ancient Life History of the Earth, Project Gutenberg (public domain). (also onWikimedia commons)

Protorosaurus:Protorosaurus speneri von Meyer, 1830.

Synonym:Proterosaurus (variant spelling)

Comments: The earliest known Archosauromorph. Although frequently illustrated as a complete skull and skleleton, or life reconstruction, and often mentioned, this is a poorly known form. Included first in the Euryaspida, later in the Prolacertiformes. Although similar toProlacerta, there are many aspects of its anatomy that are still controversial (Benton 1985), and it may have a more basal position. (Borsuk-Białynicka & Evans, 2009). Although usually reconstructed as semi-aquatic, these animals were more probably fully terrestrial, very similar in lifestyle and appearance to extant monitor lizards (Varanidae). It is quite likely that the Protorosaurs and Prolacertifomes simlarily usedgular pumping of the hyoid skeleton to ventilate the lungs more efficiently. (Dr John Merck -Archosauromorpha). The life- reconstruction ofProlacerta at the top of the page could equally apply toProtorosaurus or the relatedCzatkowiella.

Links:Wikipedia -Dinocasts com life-sized cast (along with replica fossils and reconstructions of other permian fauna) very nice although the grass spoils the effect (grass didn't appear until the early Tertiary) MAK101008

The basal archosauromorphCzatkowiella harae, Early Triassic of Czatkowice, Poland. Reconstruction of the skull, (length about 4 cm) in dorsal (A), ventral (B), and lateral (C) views. fromBorsuk-Białynicka & Evans, 2009. This was a long necked animal very similar in appearance to, but smaller than,Protorosaurus andProlacerta

Czatkowiella:Czatkowiella harae Borsuk-Białynicka & Evans, 2009.

Comments: resemblesProtorosaurus but differs enough to justify distinct generic status. Both show diagnostic long-necked "prolacertiform" characteristics (loss of the parietal foramen, distinct transverse processes on the dorsal vertebrae, double-headed ribs), but cladistic analyses does not recover a monophyletic Prolacertiformes. Czatkowiella and Protorosaurus represent basal archosauromorphs with few specialised or common characteristics; the traditional prolacertiforms, like theyounginiformes, probably represent a basal assemblage grouped together because of shared primitive (plesiomorphic) characteristics the retention of primitive character states. Ifichthyosaurs,sauropterygians, andtestuduines arearchosauromorphs, they would derive from this early evolutionary assemblage of long-necked lizard-like forms.

References:Borsuk-Białynicka & Evans, 2009.

Links:Wikipedia MAK101007