Ontogenetic and sexual variation in cranial characters of Aegialomys Xanthaeolus (Thomas, 1894)(Cricetidae: Sigmodontinae) from Ecuador and Peru

Author(s)

Joyce R. Prado ; Alexandre R. Percequillo ^[2]

• Document type: Journal article
• Source: Papéis Avulsos de Zoologia (São Paulo); v. 51, n. 9, p. 155-177, 2011-00-00.

Abstract

Aegialomys xanthaeolus (Cricetidae: Sigmodontinae) inhabits the arid montane areas of western Ecuador and Peru, and higher elevations in the upper Marañón valley in northern Peru. Some researchers have included this species in broader systematic assessments over the years, but there are no comprehensive studies focusing on intraspecific variation. There are several sources of intraspecific phenotypic variation, including sexual dimorphism and age. These sources may confound the assessment of similarity/dissimilarity among populations, therefore it is essential that non-geographic variation is evaluated before studies on geographical variation and species delimitation are carried out. Here we summarize existing information regarding the geographical distribution of A. xanthaeolus and evaluate variation related to sex and age. We analyzed 19 traditional cranio-dental measurements taken from specimens housed in scientific collections, and organized the collecting localities of specimens examined in a gazetteer and plotted them on a distribution map. Uni and multivariate statistical analyses allow us to assert that age variation was significant, as age classes 3, 4 and 5 can be pooled for the subsequent analysis of geographic variation and that sexual dimorphism is not a consistent component of variation within this species in the continental samples, when considering samples from the same locality, or localities close to each other. (AU)

• FAPESP's process: 09/16009-1 - Systematics, evolution and diversification of the subfamily Sigmodontinae in South America: the tribe Oryzomyini
• Grantee: Alexandre Reis Percequillo
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 98/05075-7 - Systematics, Evolution and Conservation of Eastern Brazilian Mammals
• Grantee: Mario de Vivo
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 09/03547-5 - TAXONOMIC REVIEW OF AEGIALOMYS (WEKSLER, PERCEQUILLO & VOSS, 2006) (CRICETIDAE: SIGMODONTINAE)
• Grantee: Joyce Rodrigues Do Prado
• Support Opportunities: Scholarships in Brazil - Master