Variación intraespecífi ca en Cryptotis aroensis (Mammalia, Soricomorpha, Soricidae) de Venezuela

Abstract

Introduction: In Venezuela, the genus Cryptotis Pomel 1848 is represented by four species: C. meridensis Thomas 1898, C. tamensis Woodman 2002, C. aroensis Quiroga-Carmona and Molinari 2012; and C. venezuelensis Quiroga-Carmona 2013 (Quiroga-Carmona and Molinari 2012; Quiroga-Carmona 2013). C. meridensis, and C. tamensis have been documented in the Andes (Cordillera de Mérida, El Tamá, and Sierra de Perijá). On the other hand, C. aroensis, and C. venezuelensis are recorded only in the Cordillera de la Costa (Sierra de Aroa, and Serranía del Litoral). Cryptotis aroensis, was recently described and is known from only three specimens from type locality (Sector Milla, Sierra de Aroa, Yaracuy State), in Northern Venezuela. Based on a new series (45 specimens) from Yurubí National Park, Sierra de Aroa, Yaracuy State, Venezuela, in this article, we evaluated the intraspecifi c variations of Cryptotis aroensis, previously unknown in the literature.Metodology: Specimens studied are preserved in the Museo de la Estación Biológica de Rancho Grande (EBRG, Aragua State, Venezuela), and the Museo de Zoología, Universidad de Carabobo (MZUC, Carabobo, State, Venezuela). External measurements (mm) and weight (g) were taken from the colector’s tag. Craniodental terminology follows Woodman (2002, 2003), Quiroga-Carmona and Molinari (2012), and Woodman et al. (2013), and the craniodental measurements were taken with a digital caliper. Finally, for each measure, mean and range were calculated and we used a Student t test with intervals confi dence not less than 95% to explore differences related to sex.Results: Our morphological and metric analysis indicates that specimens of Cryptotis aroensis from Yurubí National Park are smaller and with longer tails, compared with C. meridensis, C. tamensis and C. venezuelensis. There were no signifi cant differences between sexes for the individuals studied, suggesting that there is no sexual dimorphism in C. aroensis. Within this sample there were highly variable morphological characters such as the shape of the wart on the nasolabial groove in the rhinarium, numbers of postnasal warts on the muzzle, hindlimb digits, presence and position of the fourth unicuspid tooth, presence and size of dorsal foramina on the skull, presence and size of foramina on posterior border of tympanic process of petromastoids. The humerus was slightly smaller, less robust and slightly curved in C. aroensis compared with one humerus available for C. meridensis.Discussion: The high intraspecifi c variation in C. aroensis is consistent with previous reports that indicates a high morphological and metric variation among individuals in the groups Cryptotis nigrescens (Woodman and Timm 1993), C. goldmani (Woodman and Timm 1999; Woodman 2011), C. thomasi (Woodman 2002), C. mexicana (Ramírez-Pulido et al. 2004), and C. parva (Ramírez-Pulido et al. 2004). With respect to the characters in the original description of C. aroensis (Quiroga-Carmona and Molinari 2012), there are similarities when the sample increases from three (holotype and two paratypes) to 45 specimens. Such characters include body-head length, and length of mandible, besides the presence of cusps on the third upper molar that defi ne a complex molar. Additionally, the result of this study suggests that tail length (extremely long) can be useful to separate C. aroensis of the different taxa in Venezuela. When we compared the type series of C. venezuelensis, a species known only from three specimens from the Cordillera de la Costa, like C. aroensis (Quiroga-Carmona 2013), there are several similarities in morphology and metrics. Those characters include its size and body coloration, presence and visibility of the fourth unicuspid tooth, shape of the wart and its extension on the nasolabial groove in the rhinarium, the numbers of postnasal warts, size and shape of the angular and coronoid processes, and the average of scales per centimeter on the tail. These characters suggest that C. aroensis and C. venezuelensis might be closely related taxa.