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We investigated the occurrence of congenital dental abnormalities in 94 wild boars Sus scrofa scrofa, and 20 Iberian pigs Sus scrofa domesticus from Doñana (DNP) and Sierra de Andújar Natural Park (ANP) southern Spain. The only dental variation found was agenesis of the lower first premolar, either deciduous (Dp1) or permanent (P1). We analyzed prevalence variations using: odds ratios, Fisher's exact test and logistic-regression models. The lower first premolar has often been reported to be absent in modern domestic breeds of pigs, but it is usually reported as present in wild boar. However, we found a similar occurrence of agenesis in wild boar as in Iberian pigs. A common genotypic background between wild boar and Iberian pig populations of ANP sharing the same ecosystems may explain this result. When considering only wild boar, unexpected differences between populations were detected. The wild boar from ANP showed higher estimated probabilities of agenesis than those from DNP. Environmental conditions can also represent influencing factors for changes within subspecies. Our findings reinforce the idea that in suids the congenital absence of premolars probably has an evolutionary relevance, which could represent a generalized trend towards the reduction of the dental formula from the plesiomorphic placental dentition. [ABSTRACT FROM AUTHOR]

Semiaquatic habits evolved in several Sigmodontinae rodent species, but this issue remains poorly studied. The marsh rat Holochilus vulpinus (Brants, 1827) has been associated with palustrine wetland environments and exhibits several morphological traits related to the semiaquatic habit. However, its swimming behavior and the way its morphological specializations contribute to it have not been evaluated so far in this species. This note focuses on describing and quantifying the swimming behavior and swimming performance of H. vulpinus. In order to address these issues, five individuals of H. vulpinus, four adults and one subadult, were filmed while swimming and their performance was quantified. The obtained results indicate that the swimming mode is bipedal paddling, alternating the stroke of the hind feet. The quantitative indicators also qualify H. vulpinus as a good swimmer compared to other terrestrial and semiaquatic mammals. [ABSTRACT FROM AUTHOR]

The echimyid rodents of the genus Phyllomys are medium-sized arboreal spiny rats endemic to the Atlantic Forest of Brazil. The genus is currently composed of 13 species, although there are at least four other undescribed species. The ecology, zoogeography and diversity of the genus are still poorly understood. Here, we provide the first record of Phyllomys sulinus from the Brazilian state of Rio de Janeiro, based on a specimen collected in the Serra da Bocaina National Park, which extends the known geographic range of the species approximately 130 km to the northeast. At this site, P. sulinus occurred in syntopy with the cryptic Phyllomys nigrispinus. We describe the karyotype of P. nigrispinus for the first time and identify two different diploid numbers (2n=84 and 85). We also conducted a molecular analysis of the cytochrome b gene of five specimens, which we identified by phylogenetic reconstruction. Our findings reinforce the importance of molecular data, such as DNA sequences, and karyotypes for the differentiation of cryptic, syntopic species. [ABSTRACT FROM AUTHOR]