Evolutionary trends on extant cat skull morphology (Carnivora: Felidae): a three-dimensional geometrical approach

Abstract

The skulls of 33 extant cat species were characterized through three-dimensional geometric morphometrics using 20 landmarks. A principal component analysis (PCA) was performed with Procrustes fitted coordinates, and the PC-scores were phylogenetically corrected by independent contrasts method. Three PCs allowed for the definition of five cat skull patterns. PC1: 'snouted/massive-headed cats' (genus Panthera) opposing the 'round-headed small cats' (genus Oncifelis, Prionailurus rubiginosus, Prionailurus bengalensis, among other small cats); PC2: 'taperingheaded cats' (Neofelis nebulosa, Herpailurus yagouaroundi, Prionailurus planiceps) opposing the 'stout-headed cats' (Acinonyx jubatus, Uncia uncia, Otocolobus manul, Felis margarita, and Felis nigripes); and PC3: 'low profiledheaded cats' (mostly, Pr. planiceps). A sixth pattern, the 'generalized skull', observed in the Caracal lineage, genus Lynx, Leopardus pardalis, and Catopuma temminckii, indicates a morphological convergence among midsized-cats. The morphological trends 'snouted/massive' and 'round' clearly denote a co-evolution between size and shape. The other skull patterns evolved unrelatedly to the size (i.e. their allometric variations are not a size function). Nevertheless, each species comprises an amalgam of these patterns, so the influence of the size permeates, in some extent, the skull morphology along all cat lineages. The felid ecomorphological fit to hypercarnivory is obvious; however, different skull shapes in same-sized species with similar habits, indicate that the variation in the skull morphology may result from phenotypic fluctuations, whose adaptive value (if indeed there is any) is still obscure.

Anyone with a Long-Face? Craniofacial Evolutionary Allometry (CREA) in a Family of Short-Faced Mammals, the Felidae

“…3D analyses might confirm the pattern we found in 2D ventral views, as suggested by Sicuro (2011) noticing that several species of small cats are round-headed, while an elongated snout is the most typical aspect of the large species of the genus Panthera. His work, as the previous two-dimensional analysis by Slater & Van Valkenburgh (2008), did not test differences between subfamilies.…”

“…However, whether the same patterns will be found on the dorsal side and, even more accurately, using 3D landmarks and semilandmarks over the entire cranium, is something that will have to be assessed in future studies but seems likely based on previous work, at least for facial elongation (Slater & Van Valkenburgh 2008;Sicuro 2011). …”

“…Previous work on cranial morphology in felids suggested that the the face grows faster than the braincase during ontogeny (Segura et al 2013(Segura et al , 2016 and that (Slater & Van Valkenburgh 2008;Sicuro 2011) larger species do tend to be long-faced. However, those studies did not have a specific focus on assessing the CREA pattern, and, for instance, said little on braincase size and did not test the sensitivity of results to the way relative proportions of cranial regions were measured.…”

“…Neofelis is less well known than most other pantherines and certainly atypical for being the living felid with proportionally longest canines, as well as for other cranial features, including an elongated and relatively narrow skull (Werdelin 1983;Sicuro 2011;Sicuro & Oliveira 2011). …”

Three-dimensional cranial ontogeny in pantherines (Panthera leo,P. onca,P. pardus,P. tigris; Carnivora:, Felidae)

“…low morphological diversity) (Ewer, 1973); this fact could be related to their restricted hypercarnivorous diet that could have acted as an evolutionary constraint (Holliday & Steppan, 2004). Even though the Felidae are considered to be homogeneous in skull morphology (Goswami, 2006;Sunquist & Sunquist, 2009;Sicuro, 2011), the Puma lineage shows noteworthy differences (Segura, Prevosti & Cassini, 2013); thus, the conservative shape of skull is directly related to the taxonomic level used in the work.…”