Abstract
BackgroundCaenolestids are a group of poorly known South American marsupials with a restricted distribution in Páramo and Subpáramo environments of the Andes from Colombia and western Venezuela to Bolivia (represented by the genera Caenolestes and Lestoros), and Valdivian rainforest in southern Chile (including a separate population in Chiloé Island) and Argentina, where a single species lives: the Long-nosed shrew opossum (Rhyncholestes raphanurus). The objectives of this work were to analyze the intraspecific variability of R. raphanurus, which includes an anatomical description of the skull and dentition, describe its geographic variation, test for sexual dimorphism, and assess potential differences between continental and Island populations.MethodsLinear Mossimann-transformed variables were used to assess sexual differences within a large population (La Picada), compare sexes within other continental populations, and in a separate analysis, compare continental from Island samples. A full model Principal Components Analysis was performed to assess differences between males and females of the continental and Island populations. A thorough description of the skull and teeth of the species and comparisons with other living Caenolestidae is presented.ResultsRhyncholestes raphanurus presents little geographic variation, even between Island and continental populations. Similarly, we found no significant difference between sexes of this species in cranial and dental measurements. We provide a detailed description of cranial morphology and its variation, and also, the first description of the occipital bones, which haven’t been previously described for any Paucituberculata.ConclusionsComparative studies of continental and Chiloé Island specimens support the treatment of R. raphanurus as a single valid species, especially since morphologic and morphometric differences fall within the extremes of continental populations. The morphology of R. raphanurus clearly separates this genus from other extant Caenolestidae, and in a much greater degree than the differences found between Lestoros and Caenolestes.
Highlights
Caenolestids are a group of poorly known South American marsupials with a restricted distribution in Páramo and Subpáramo environments of the Andes from Colombia and western Venezuela to Bolivia, and Valdivian rainforest in southern Chile and Argentina, where a single species lives: the Long-nosed shrew opossum (Rhyncholestes raphanurus)
Three genera are currently recognized within Caenolestidae: Caenolestes, with five described species living in the high Andean ecosystems of the northern Andes of northern Perú, Ecuador, Colombia, and southwestern Venezuela; Lestoros, with a single species (L. inca) living in the high Andean ecosystems of southern Perú and northern Bolivia; and Rhyncholestes, with a single species (R. raphanurus) living in the Valdivian rainforest of Chile and Argentina [2, 3]
Others show an intraspecific variability related to sexual dimorphism (e.g., M1 in continental samples; Table 4), or a small sample that was constrained towards an extreme within the variability (e.g., M1–3 and width of M3 in the sample from Chiloé; Table 5, and Additional file 1)
Summary
Caenolestids are a group of poorly known South American marsupials with a restricted distribution in Páramo and Subpáramo environments of the Andes from Colombia and western Venezuela to Bolivia (represented by the genera Caenolestes and Lestoros), and Valdivian rainforest in southern Chile (including a separate population in Chiloé Island) and Argentina, where a single species lives: the Long-nosed shrew opossum (Rhyncholestes raphanurus). Three genera are currently recognized within Caenolestidae: Caenolestes, with five described species living in the high Andean ecosystems of the northern Andes of northern Perú, Ecuador, Colombia, and southwestern Venezuela; Lestoros, with a single species (L. inca) living in the high Andean ecosystems of southern Perú and northern Bolivia; and Rhyncholestes, with a single species (R. raphanurus) living in the Valdivian rainforest of Chile and Argentina [2, 3]. Osgood [9] anticipated the presence of this species in continental Chile, which was later confirmed by individuals trapped by Sanborn in 1939 (a single adult male), and Gallardo [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
