Phylogeography of screaming hairy armadillo Chaetophractus vellerosus: Successive disjunctions and extinctions due to cyclical climatic changes in southern South America

Forelimb myology of armadillos (Xenarthra: Cingulata, Chlamyphoridae): Anatomical correlates with fossorial ability

Descriptions of myology reflect adaptations of the post-cranium and are essential for understanding the functional morphology of animal limbs. Armadillos (Cingulata) are the most species-rich group of the basal superorder Xenarthra, which is evident by their various lifestyles (subterranean vs. terrestrial) and levels of fossoriality (fossorial vs. semi-fossorial). While there have been several studies on limb bone proportions in numerous armadillos, limb myology has been reported for a limited number of species. Many of these descriptions need updating, and detailed quantitative muscle data are available only for nine-banded armadillos. The main objective of this study is to assess the forelimb myology of the pichi (Zaedyus pichiy), screaming hairy (Chaetophractus vellerosus), large hairy (Chaetophractus villosus), and pink fairy (Chlamyphorus truncatus) armadillos with comparisons to previous observations to specify muscle traits that indicate scratch-digging specializations in cingulates. Several myological features are variable among the species studied, including the origin of m. trapezius pars cervicalis, presence of a distinct m. rhomboideus profundus and m. omotransversarius, and number of heads present for m. triceps brachii and m. flexor digitorum profundus, all of which can be associated with variability in their respective habitats and functional habits. These traits are consistently observed in the members of the Euphractinae, whereas they are slightly divergent (i.e., reduced complexity) in the pink fairy armadillo despite a similar distribution of muscle mass in the limb retractors, elbow extensors, and carpal/digital flexors across species. The ecomorphology observed here among cingulates also confirms their recent reorganization into separate families and subfamilies.

Anthropogenic invaders: historical biogeography, current genetic status and distribution range of the “peludo” Chaetophractus villosus (Xenarthra) in Patagonia and Tierra del Fuego, southern South America

Chaetophractus villosus was once distributed from the south of Bolivia and Paraguay to the northwest of Patagonia, where the species survived in glacial refugia during Pleistocene. After the ice retreated, the species expanded its distribution further south reaching Chubut River. In the last two centuries, the species colonized the rest of Patagonia on both sides of the Andes and was introduced in Tierra del Fuego (TDF) in 1982, where it expanded its distribution range along 484 km2 until 2005. A single mitochondrial Control Region haplotype (HC) was described across Argentine Patagonia based on the low number of samples. This lack of variability was exceptional and impressive, taking into account that the northern neighboring areas of distribution are considered ancestral due to the haplotype richness. Here, we added new field and genetic data and compiled recent bibliography to update the biogeography and phylogeography of the species in southern South America. To explain the unprecedent lack of genetic variability, we discussed three main aspects: a historical biogeographic aspect related to the natural barriers for the species, a strong stochastic component, and the possible adaptive advantages of the only mitochondrial lineage detected, whose colonization and acclimatization to the new environment were mediated by man. We also estimated that the current distribution range in TDF is about 8527 km2.

Helminth fauna of the screaming hairy armadillo Chaetophractus vellerosus from Argentina: the consequence of host isolation on parasite diversity

Chaetophractus vellerosus in Argentina has a north-west and central distribution. An isolated population is located in the east of the Buenos Aires province, separated from the population of central Argentina by about 500 km. We compared the component community of C. vellerosus between the main population in central Argentina and the isolated population, evaluating the impact of the host isolation on parasite diversity. Sixteen species of helminths were found, namely Ancylostoma caninum, Aspidodera fasciata, Aspidodera scoleciformis, Mazzia bialata, Pterygodermatites chaetophracti, Pterygodermatites argentinensis, Strongyloides sp., Trichohelix tuberculata, Cruzia tentaculata, Cyclobulura superinae, Delicata ransomi, Macielia jorgei, Moennigia celinae, Orihelia anticlava (Nematoda), Mathevotaenia sp. (Cestoda) and Travassosia sp. (Acanthocephala). Only the first 8 species, however, were present in both populations. Prevalences and intensities of the shared species were similar. The parasite community of the isolated population, however, was less rich and diverse than that of the main population. The poor parasite community in the isolated population could have several causes: the founding population was composed of few specimens that were only infected with the most prevalent parasite species and intermediate hosts for parasites with indirect cycles were absent. In addition, coexistence with another Chlamyphoridae would have contributed to maintaining a group of species that are usual in armadillos along their distribution.