Cutleria, Another Basal Therapsid

Laurin (1994) redescribed a small synapsid, Cutleria wilmarthi, (Lewis and Vaughn 1965) as a sister to the Sphenacodontidae + Therapsida at a time when therapsids were thought to descend from sphenacodontids. Here a close relationship to the derived ophiacodontid and basal therapsid, Stenocybus is noted (fig. 1).

Cutleria compared to Stenocybus.

Figure 1. Cutleria compared to Stenocybus. Click to enlarge. Smaller canines in Cutleria nest it closer to the early herbivore clan of Dicynodontia + Dromosauridae. Color added to restore the skull

Laurin (1994) got it right. This specimen is a close taxon to the Therapsida and not far from the Sphenacodontia. Unfortunately, Laurin (1994) published three years before Stenocybus was described by Cheng and Li (1997).

The smaller canines and lower snout mark this taxon as close to Nikkasaurus and the herbivorous clade of Dromosauridae + Dicynondontia.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Laurin, M 1994. Re-evaluation of Cutleria wilmarthi, an Early Permian synapsid from Colorado. Journal of Vertebrate Paleontology 14(1): 134-138.
Lewis GE and Vaughn PP 1965. Early Permian Vertebrates from the Cutler Formation of the Placerville Area Colorado. United States Geological Survey Professional Papers 503-C:1-50.
Cheng Z and Li J 1997. A new genus of primitive dinocephalian – the third report on Late Permian Dashankou lower tetrapod fauna. Vertebrata PalAsiatica 35 (1): 35-43. [in Chinese with English summary]

 

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