Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation

<p>Abstract</p> <p>Background</p> <p>Adaptive radiation, the evolution of ecological and phenotypic diversity from a common ancestor, is a central concept in evolutionary biology and characterizes the evolutionary histories of many groups of organisms. One such group is the Mustelidae, the most species-rich family within the mammalian order Carnivora, encompassing 59 species classified into 22 genera. Extant mustelids display extensive ecomorphological diversity, with different lineages having evolved into an array of adaptive zones, from fossorial badgers to semi-aquatic otters. Mustelids are also widely distributed, with multiple genera found on different continents. As with other groups that have undergone adaptive radiation, resolving the phylogenetic history of mustelids presents a number of challenges because ecomorphological convergence may potentially confound morphologically based phylogenetic inferences, and because adaptive radiations often include one or more periods of rapid cladogenesis that require a large amount of data to resolve.</p> <p>Results</p> <p>We constructed a nearly complete generic-level phylogeny of the Mustelidae using a data matrix comprising 22 gene segments (~12,000 base pairs) analyzed with maximum parsimony, maximum likelihood and Bayesian inference methods. We show that mustelids are consistently resolved with high nodal support into four major clades and three monotypic lineages. Using Bayesian dating techniques, we provide evidence that mustelids underwent two bursts of diversification that coincide with major paleoenvironmental and biotic changes that occurred during the Neogene and correspond with similar bursts of cladogenesis in other vertebrate groups. Biogeographical analyses indicate that most of the extant diversity of mustelids originated in Eurasia and mustelids have colonized Africa, North America and South America on multiple occasions.</p> <p>Conclusion</p> <p>Combined with information from the fossil record, our phylogenetic and dating analyses suggest that mustelid diversification may have been spurred by a combination of faunal turnover events and diversification at lower trophic levels, ultimately caused by climatically driven environmental changes. Our biogeographic analyses show Eurasia as the center of origin of mustelid diversity and that mustelids in Africa, North America and South America have been assembled over time largely via dispersal, which has important implications for understanding the ecology of mustelid communities.</p

Microanatomy and histology of bone pathologies of extant and extinct phocid seals

This study investigates three presumed fractured phocid seal bones: An isolated metapodial and an ulna belonging to different individuals of the extinct phocid, Homiphoca capensis, from Langebaanweg and a mandible of a juvenile elephant seal (Mirounga leonina), which was included to assess the validity of the assumption that changes to bones caused by fractures are consistent across extant and extinct members of the same groups. The bones were studied using a multi-method approach, including gross morphology, microcomputed tomography (micro-CT) and histology. Micro-CT showed that the metapodial was not fractured and information drawn from other analyses suggested that the pathology was an osteosarcoma. Histology of normal and fractured regions of the mandible and ulna permitted an estimate about the fracture healing stage, and showed the bone tissue at the fracture sites to be histologically similar. A birth line found on the lateral surface of the elephant seal mandible emphasised its young age and marked the first example of a birth line in a bone of a semi-aquatic mammal. A large scope of information was obtained using this multi-method approach, which could permit insight into the life events and lifestyles of modern and extinct individuals, such as H. capensis.NRF-DST Centre of Excellence in Palaeosciences to Megan Rose Woolley, NRF African Origins Programme (AOP) Grant awarded to Prof A Chinsamy-Turan (Grant No. 117716) NRF African Origins Programme (AOP) Grant awarded to Dr R Govender (Grant No. 98834).https://www.tandfonline.com/loi/ghbi202020-11-12hj2020Mammal Research InstituteZoology and Entomolog

Is Aardwolf A Mimic Of Hyaena

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62752/1/253191a0.pd