Kerodon

Abstract: The rock cavy Kerodon rupestris (Wied-Neuwied, 1820) is a rodent species endemic to northeastern Brazil. Earlier studies have associated the argasid tick Ornithodoros talaje (Guerin-Meneville, 1849) with rocky cavy; however, a recent study proposed that O. talaje is not established in Brazil, where previous reports of this species were possibly misidentifications of closely related species, yet to be properly determined. Here, we describe a new species of Ornithodoros Koch, 1844 associated with rock cavies in northeastern Brazil. During 2012–2013, Ornithodoros ticks were collected from K. rupestris resting places in Paraiba State (PB) and Piaui State (PI), northeastern Brazil. These ticks were brought alive to the laboratory, and used to form two laboratory colonies (PB and PI ticks). Field-collected adults and laboratory-reared larvae were used for morphological description through light and scanning electron microscopy. DNA sequences of the mitochondrial 16S rRNA gene were generated from nymphal ticks and used to conduct phylogenetic analyses along with other Ornithodoros spp. sequences from GenBank. Reproductive compatibility of crosses between PB and PI adult ticks was evaluated, as well as analyses of hybrid ticks through larval morphology by a principal components analysis (PCA) and DNA sequences of the second internal transcribed spacer (ITS2) region from adult ticks. Morphological analysis allowed recognizing these ticks as a new species, Ornithodoros rietcorreai n. sp. The larva of O. rietcorreai is distinct from those of other Ornithodoros spp. by the combination of the following character states: 14 pairs of dorsal setae, dorsal plate pyriform, hypostome with pointed apex and dental formula 3/3 anteriorly, 2/2 posteriorly, and anal valves with long and pointed leaf-shaped ends. There were a few larval morphological differences between PB and PI ticks, and their mitochondrial 16S rDNA sequences diverged by 3.3 %. On the other hand, cross-mating experiments showed that PB and PI ticks were reproductive compatible, indicating that they represent a single species. Analyses of ITS2 sequences and PCA corroborated this assumption. Ornithodoros rietcorreai is described as a new species associated with K. rupestris in Brazil, increasing the Brazilian tick fauna to 70 species.

Abstract: Etude de la reproduction en captivite d'un rongeur caviomorphe, Kerodon mpestris, de mai 1978 ä mars 1982. La reproduction du Kerodon differe nettement de celle de genres proches parents qui ont fait 1'objet d'etudes jusqu'ä present. Elle est caracterisee par de petites portees de jeunes tres pr£coces, par une gestation longue et une maturite sexuelle retardee. Ces caract£ristiques semblent en rapport avec un mode d'alimentation particulier dans un milieu ecologique aride et isole* qui a contribue* a eloigner les strategies biologiques du Kerodon de celles qui sont typiques chez les autres genres de la sous-famille des Caviinae.

Abstract: Trichuris eggs were observed in Kerodon rupestris coprolites dated 9,000 years before present, collected in archeological sites of Sao Raimundo Nonato, northeastern Brazil. However, present day local rodents seem not to be infected by the parasite, suggesting its disappearence due to climatic changes.

Abstract: The present study describes the fetal regions ethmoidalis and orbitotemporalis of the cranium of Galea musteloides and Kerodon rupestris and compares them with Galea spixii and Cavia porcellus. The fetal crania of these representatives of the Caviinae were serially sectioned and 3D plate reconstructions were built. For a broader scope, serially sectioned heads of the caviomorph taxa Hydrochaeris hydrochaeris and Dasyprocta leporina were also examined. The ethmoidal and orbitotemporal regions of the cranium provides characters that are pertinent to the discussion of systematics of the Caviinae. Nine cranial characters were identified as being significant and discussed phylogenetically. Taking the monophyly of the Cavioidea as given, two characters are autapomorphic for the genus Galea: the reduction of the crista semicircularis and the lacrimale forming the ‘arco antorbitario’ (Kraglievich 1930). Cavia is the sister group of Galea; synapomorphic characters are the extent of the processus palatinus medialis of the praemaxillare and the presence lamina pterygoidea of the alisphenoid. There were no apomorphic characters of the structural complexes examined that could support the Caviinae. The reduced and nonperforated alisphenoid is an autapomorphic feature of the Caviidae. The division of the nasoturbinale is evidence for a sistergroup relationship of the Hydrochaeridae and the Caviidae. Autapomorphic characters for the Cavioidea include the ventrolateral opening of the organon vomeronasale and the lateral prolongation of the lacrimale.