Resurrecting extinct taxa: Pareiasauria, Compsognathidae and Ophiacodontidae

Earlier we looked at
four clades thought to be extinct, but are not extinct based on their nesting in the large reptile tree (LRT, 1366 taxa). Today, three more:

Figure 2. Another gap is filled by nesting E. wuyongae between Bunostegos and Elginia at the base of hard shell turtles in the LRT.

Figure 1. Another gap is filled by nesting E. wuyongae between Bunostegos and Elginia at the base of hard shell turtles in the LRT.

Pareiasauria
According to Wikipedia, “Pareiasaurs (meaning “cheek lizards”) are an extinct group of anapsid reptiles classified in the family Pareiasauridae. They were large herbivores that flourished during the Permian period.”

In the LRT two clades of turtles (Fig. 1) are derived in parallel from two small horned pareiasaurs.

Figure 1. Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently.

Figure 2.  Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently.

Compsognathidae
According to Holtz 2004, “The most inclusive clade containing Compsognathus longipes but not Passer domesticsus.” Traditionally Compsognathus nests outside the Tyrannoraptora, a clade that traditionally leads to birds.

In the LRT Compsognathus specimens nest at the base of several theropod clades (Fig. 2) including the tyrannosaurs and Mirischia, Ornitholestes and the feathered theropods leading to birds.

Figure 1. Varanosaurus, Ophiacodon, Cutleria and Ictidorhinus. These are taxa at the base of the Therapsida. Ophiacodon did not cross into the Therapsida, but developed a larger size with a primitive morphology. This new reconstruction of Ophiacodon is based on the Field Museum (Chicago) specimen. Click to enlarge.

Figure  3. Varanosaurus, Ophiacodon, Cutleria and Ictidorhinus. These are taxa at the base of the Therapsida. Ophiacodon did not cross into the Therapsida, but developed a larger size with a primitive morphology. This new reconstruction of Ophiacodon is based on the Field Museum (Chicago) specimen. Click to enlarge.

Ophiacodontidae
According to Wikipedia, “Ophiacodontidae is an extinct family of early eupelycosaurs from the Carboniferous and Permian. Ophiacodontids are among the most basal synapsids, an offshoot of the lineage which includes therapsids and their descendants, the mammals. The group became extinct by the Middle Permian.”

In the LRT Ophiacodon (Fig. 3) and Archaeothyris, neither members of the Pelycosauria, are more directly related to basal therapsids, including derived the therapsids: mammals.

References
Holtz TR 2004. Basal tetanurae. PP. 71–110 in The Dinosauria, U of California Press.

/wiki/Pareiasaur
wiki/Ophiacodontidae

 

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