SVP 2018: new Whatcheeria data from nearly 100 specimens

Last one for this year.
This post finishes up an inundation of about 40 2018 SVP abstract reviews. We’ll get back to a regular one-a-day look at paleo news later today.

Otoo, Bolt and Lombard 2018
bring us new information on Whatcheeria (Fig. 1), a basal tetrapod (Fig. 2) now known from nearly 100 specimens. In the large reptile tree (subset Fig. 2, LRT) the Whatcheeria clade nests between the primitive Ossinodus clade and the Ichthyostega clade plus all higher tetrapods. The authors report, “Whatcheeria is key for establishing character polarities on the tetrapod stem, particularly in the context of recent controversies about age of the tetrapod crown group and the timing and pattern of the lissamphibian/amniote split.” In the LRT Tulerpeton and Eucritta have taken over that role.

Figure 3. Pederpes is a basal taxon in the Whatcheeria + Crassigyrinus clade.

Figure 1. Pederpes is a basal taxon in the Whatcheeria + Crassigyrinus clade.

After a short description
of key Whatcheeria traits, and without describing a phylogenetic analysis, Otoo, Lombard and Bolt conclude: “This combination of features in the femur emphasizes the moasic of characters present in Whatcheeria, and, in conjunction with recent Tournaisian discoveries, emphasizes the complexity of post-Devonian tetrapod evolution.”

A subset of the LRT
(Fig. 2) portrays post-Devonian tetrapod evolution rather differently and rather simply

Figure 1. Subset of the LRT focusing on basal tetrapods, colorized according to chronology. Note the wide dispersal of Early Carboniferous taxa, suggesting a Late Devonian radiation as yet largely undiscovered.

Figure 2. Subset of the LRT focusing on basal tetrapods, colorized according to chronology. Note the wide dispersal of Early Carboniferous taxa, suggesting a Late Devonian radiation as yet largely undiscovered.

References
Otoo BK, Bolt JR, Lombard E 2018. A leg up: Whatcheeria and its new contributions to tetrapod anatomy. SVP abstracts.

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