Geographic Variation in Cranial Morphology of the Southern Mountain Cavy, Microcavia australis (Rodentia, Caviidae): Taxonomic Implications, with the Description of a New Species

Pablo Teta, Ricardo A. Ojeda, Sergio O. Lucero, and Guillermo D'Elía (2017) We analyzed the geographic variation in cranial morphology of the Southern Mountain Cavy, Microcavia australis, throughout of its distributional range. Our analysis allows us to recognize three geographically allopatric morphotypes. These morphotypes differ in the general size and shape of the skull and discrete morphological traits of the zygomatic arch, palate and mesopterygoid fossa. Based on these results, we restrict the name australis to populations distributed in southern Argentina and west-central Andes and the name maenas to the morphotype of northwestern and central Argentina. The third morphotype occurs in the Dry Chaco ecoregion and is described here as a new species.

Population genetic structure and molecular diversity of the red swamp crayfish in China based on mtDNA COI gene sequences

Population genetic structure and molecular diversity are closely related to adaptability, potential and evolutionary of a species, which also reflects its population history. We analyzed the molecular variability and genetic structure among 24 populations of the red swamp crayfish in China based on the COI region. The COI of 687 bp aligned across 44 haplotypes, the average AT content (68.1%) was slightly higher than the AT content (31.9%). AMOVA indicated that a high proportion of the total genetic variance was attributable to variations within populations (87.57%), whereas only 12.43% occurred among populations. The Fst values were between 0.016 and 0.585, and the Nm values were between 0.178 and 15.182 in each population. All of the AMOVA, Fst statistics and Nm values suggested low genetic differentiation, but a high level genetic diversity existed in Chinese populations of Procambarus clarkii. The phylogenetic trees showed that some geographical populations were irregularly distributed according to the river systems while others were matched well, suggesting that genetic differentiation is created largely by geographic isolation.