taxonID	type	description	language	source
03D287C99D47B076E381FA1E25EDD30F.taxon	description	These numerical results are visualized in the most taxonomically inclusive permutation of the PC analysis (Fig. 32). Due to difficulty in obtaining reliable limb measurements for Seymouria, it was excluded from this permutation, though the measurements are reported in Table 2. Three morphotypes are discernible: those with large, equal-length limbs (Micropholis, Orobates, Pederpes, Whatcheeria); those with medium-length, medium-disparity limbs (Balanerpeton, Eucritta, Ichthyostega, Proterogyrinus); and those with small, medium-to-high-disparity limbs (Acanthostega, Greererpeton, Trimerorhachis). There is no discernible phylogenetic clustering. All three morphotypes are represented by both stem tetrapods and crown tetrapods. Notably, Whatcheeria and Pederpes are the stem tetrapods that converge most closely with the terrestrially adapted crown tetrapods in terms of limb proportions. Although these results signal that multiple tetrapod lineages converged on similar limb proportions, extrapolations to convergent function are less clear. FUNCTIONAL ANATOMY	en	Otoo, Benjamin K A, Bolt, John R, Lombard, R Eric, Angielczyk, Kenneth D, Coates, Michael I (2021): The postcranial anatomy of Whatcheeria deltae and its implications for the family Whatcheeriidae. Zoological Journal of the Linnean Society 193 (2): 700, DOI: 10.1093/zoolinnean/zlaa182, URL: https://academic.oup.com/zoolinnean/article/193/2/700/6144098
03D287C99D47B076E381FA1E25EDD30F.taxon	description	The squat phalanges of Whatcheeria are dissimilar to those of (putatively) terrestrial taxa, which tend to be waisted with ventral grooves to accommodate ligaments to assist grasping (Clack & Finney, 2005). However, like Pederpes, the asymmetric pedal phalanges imply an anteriorly oriented foot (Figs 4, 25, 31), which in turn is a morphology associated with a walking gait (whether underwater or on land) (Clack & Finney, 2005). The significance of the breadth of the phalanges is unclear. These might have enhanced support (in or out of the water), or served as paddle-skeleton, acknowledging that broad phalanges occur in the paddles of extinct and extant tetrapods. Limb length relative to body length (Figs 2, 31, 32; Table 2) and limb robustness in Whatcheeria suggest an increased emphasis on appendicular locomotion and support compared to other early tetrapods (Fig. 32; Table 2). The tail lacks the radials and large neural and hemal spines of aquatic early tetrapods, suggesting it was less important for locomotion (although the extent of any soft-tissue fin is completely unknown). As in Proterogyrinus (Holmes, 1984), it is unlikely that Whatcheria could pull its limbs flush with the body; they would have protruded during swimming. Absence of an internal trochanter and presence of a broad fourth trochanter and well-developed femoral adductor crest suggest an emphasis on the muscles elevating the body, and de-emphasis on those associated with moving the limb in a paddle-like action (Panchen & Smithson, 1990). The morphology of the pelvic symphysis indicates that the pelvic girdle was strong and well buttressed. Extant analogues for swimming in Whatcheeria are difficult to identify, although the duckbilled platypus, Ornithorhynchus anatinus (Shaw, 1799), provides an intriguing model. The platypus uses a rowing stroke, moving the forelimbs either in conjunction or alternately (Howell, 1937; Fish et al., 1997; Fish, 2000). Like Whatcheeria, platypuses have a large and well-developed olecranon process on the ulna (with the caveats that the platypus also uses its forelimbs for digging, and that the elbow joint of Whatcheeria was not very mobile). Biomechanical research on swimming mammals shows that drag-based swimmers, such as platypuses, generate greater thrust at low speeds, increasing manoeuvrability (Fish et al., 1997; Fish, 2000; Walker & Westneat, 2000). Such capability would be useful in the context of aquatic predation. It might also have contributed to functional trade-offs needed to maintain swimming capability in the context of largely aquatic biotas, such as that of Delta (Bolt et al., 1988; Snyder, 2006; Bolt & Lombard, 2010), even as appendicular skeletal morphologies became increasingly adapted for occasional terrestrial support and locomotion. The elongate neck of Whatcheeria is the most striking feature revealed by the present reconstruction (Figs 2, 3). Neck length must have increased head mobility, relative to the primitive condition wherein the pectoral girdle is close behind the cheek (e. g. Ichthyostega and Pederpes). Such mobility would have reduced the need to move the entire body to track, grasp and manipulate prey. The increased space between the skull and pectoral girdle would also have allowed more room for jaw depression, increasing gape and throat volume. However, estimates of capacity are difficult without a preserved ceratohyal. The unusual combination of morphologies present in Whatcheeria complicates the inference of its life habits. Whatcheeria appears to have been capable of walking, and perhaps was able to undertake limited terrestrial excursions. However, it is unlikely that Whatcheeria spent most or much of its time on land, given the presence of the cranial sensory canals and lack of robust wrist and ankle joints. Moreover, the Delta fauna is dominated by aquatic taxa, so Whatcheeria likely fed mostly or solely in the water. An aquatic walking gait, as hypothesized for Seymouria (White, 1939) and Proterogyrinus (Holmes, 1984), seems plausible in Whatcheeria. Indeed, Whatcheeria may be a tetrapod specialized for walking in shallows, perhaps adapted for negotiating vegetation-choked, marginal habitats. This kind of locomotion was likely important and persistent within a range of water – land transition (s). RE- EVALUATION OF WHATCHEERIID TAXA AND SPECIMENS	en	Otoo, Benjamin K A, Bolt, John R, Lombard, R Eric, Angielczyk, Kenneth D, Coates, Michael I (2021): The postcranial anatomy of Whatcheeria deltae and its implications for the family Whatcheeriidae. Zoological Journal of the Linnean Society 193 (2): 700, DOI: 10.1093/zoolinnean/zlaa182, URL: https://academic.oup.com/zoolinnean/article/193/2/700/6144098
