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Kammerer, C. F.

Publications and source records attributed to Kammerer, C. F..

2 recordsLinked to original sources

A new skeleton of the gorgonopsian Aelurognathus tigriceps from the Daptocephalus Assemblage Zone (Karoo Basin, South Africa) with novel insights into the pelvic girdle, hind limbs, and tail

Gorgonopsian therapsids represent a transitional condition in the evolution of synapsid locomotion and postcranial structure. Most descriptions of gorgonopsians have focused on cranial material, however, limiting their usefulness for informing patterns of postcranial evolution on the mammal stem. While some recent work has begun to focus on postcrania, especially the pectoral girdle and forelimbs, comparatively little data are available on the pelvic girdle, hind limbs and tail. We report a new specimen of the late Permian gorgonopsian Aelurognathus tigriceps comprising a partial skull and well-preserved postcranial skeleton, including the near-complete series of dorsal vertebrae and ribs, complete pelvic girdle, hind limbs, feet, and a nearly complete tail. The tail is longer than any other published gorgonopsian. The new material presented here provides an opportunity to better establish broader patterns of morphology in the gorgonopsian postcranial skeleton.

paleontology↗

Incorporating continuous characters in joint estimation of dicynodont phylogeny

Continuous characters have received comparatively little attention in Bayesian phylogenetic estimation. This is predominantly because they cannot be modeled by a standard phylogenetic Q-matrix approach due to their non-discrete nature. In this paper, we explore the use of continuous traits under two Brownian motion models to estimate a phylogenetic tree for Dicynodontia, a well-studied group of early synapsids (stem mammals) in which both discrete and continuous characters have been extensively used in parsimony-based tree reconstruction. We examine the differences in phylogenetic signal between a continuous trait partition, a discrete trait partition, and a joint analysis with both types of characters. We find that continuous and discrete traits contribute substantially different signal to the analysis, even when other parts of the model (clock and tree) are held constant. Tree topologies resulting from the new analyses differ strongly from the established phylogeny for dicynodonts, highlighting continued difficulty in incorporating truly continuous data in a Bayesian phylogenetic framework.

evolutionary biology↗