Variação não-geográfica em Necromys lasiurus (Lund, 1840) (Cricetidae: Sigmodontinae) no Brasil

Abstract

Agradeço... ... em primeiro lugar, aos meus pais e à minha família, que constituem o alicerce da minha pessoa e foram fundamentais para que eu pudesse trilhar meus caminhos com segurança e tranquilidade. Também agradeço à confiança que depositaram em mim, sempre; ... aos meus amigos pelos mais diversos motivos. Não sou capaz de enumerar todos eles, e seria injusto se, ao final desta tarefa, me esquecesse de alguém, seja quem for. Cada um tem sua importância em minha vida, e sua passagem pela minha estrada, tenha sido curta curta, longa ou ainda inacabada, jamais será esquecida. Sem eles, dificilmente poderia compreender os sentimentos, as dificuldades, as diferenças entre as pessoas e o valor de uma amizade, por mais que minha família os explicasse; ... ao meu orientador, Alexandre R. Percequillo, em primeiro lugar pela oportunidade oferecida para ser seu orientado de iniciação científica, e agora pela orientação durante o Mestrado. Agradeço imensamente pelo apoio, atenção, lições e conselhos que recebi sempre, sejam sobre a profissão ou sobre a vida; ... aos companheiros de LaMa,

Small mammals of the Estação Ecológica de Bananal, southeastern Atlantic Forest, Brazil, with description of a new species of Brucepattersonius (Rodentia, Sigmodontinae)

“…The species that presented more dimorphic variables were Akodon montensis (six variables with significant divergences in subadults) and Juliomys ossitenuis (five variables with significant divergences also in subadults). These results corroborate previous studies with sigmodontine rodents which have found that, when present, sexual dimorphism is more evident in subadults (see Hingst, 1995;Camardella et al, 1998;Libardi, 2013). According to Shine (1989), sexual differences in subadults may result from divergences in niche competition at the onset of sexual maturity -a rapid increase in the cranial dimensions during this phase, more so in males, attenuates the differences with respect to females.…”

“…The lack of ontogenetic variation in the measurements of the upper molars, as observed for the LM in this study, is common in sigmodontine rodents (e.g., Voss, 1991;Brandt & Pessôa, 1994;Prado & Percequillo, 2011). However, these variables vary more in some Akodontini, at least in the lower age classes (e.g., Myers et al, 1990;Libardi, 2013).…”

“…Only between classes 4 and 5 they observed a decrease in the number of variables with significant variation. Libardi (2013), analyzing this variation in samples of Necromys lasiurus, also found significant values among all classes, which decreased, in females, between classes 4 and 5. In general, the results obtained for A. montensis collected at EEB corroborate these studies, and the fact that variation between age-classes decreases in the older classes, AC4 and AC5.…”

“…The variables IPB and IPL have a different variation pattern from all other measurements, with higher AC2 means and random variation (higher and lower means) among the age classes; the lack of age-related differences in the interparietal breadth was also observed in the species of the tribe Oryzomyini, Aegialomys xanthaeolus (Prado & Percequillo, 2011), and between classes 1 and 2 in the species of the tribe Akodontini, Necromys lasiurus (Libardi, 2013).…”

“…However, the five dimorphic measurements represent 20% of the variables analyzed. Considering that sexual dimorphism, when present in sigmodontine rodents, is more accentuated in age-class 2 (see Hingst, 1995;Camardella et al, 1998;Libardi, 2013), it is possible that these differences do not represent a great source of variation in J. ossitenuis in this and older age classes, even though they have not been evaluated.…”