Crocidura caudicrassa Esselstyn & Achmadi & Handika & Swanson & Giarla & Rowe 2021, new species

Autor: Esselstyn, Jacob A., Achmadi, Anang S., Handika, Heru, Swanson, Mark T., Giarla, Thomas C., Rowe, Kevin C.
Rok vydání: 2021
Předmět:
ISSN: 0003-0090
DOI: 10.5281/zenodo.5795541
Popis: Crocidura caudicrassa, new species LSID: urn:lsid:zoobank. org:act: 8274BDB8-B7AF-46CC-A0A8- 5EC15DC347D3 HOLOTYPE: MZB 34795, an adult female collected on 28 October 2011 by K.C. Rowe and preserved as a cleaned skull (fig. 34B), fluid-preserved body (fig. 33B), and tissue sample (NMV Z21760). External measurements are 144 mm �� 62 mm �� 17 mm �� 10 mm = 16.5g. TYPE LOCALITY: Indonesia, West Sulawesi Province, Kabupaten Mamasa, Desa Tondok Bakaru, Kampung Rantepangko, Mt. Gandang Dewata, Post 3; 2.84534�� S, 119.38216�� E, 2580��� 2640 m elevation. ETYMOLOGY: Caudicrassa is Latin for ���thick tail,��� identifying this species��� most distinctive trait. GEOGRAPHIC DISTRIBUTION: Known only from the type locality around 2600 m on Mt. Gandang Dewata and from a single specimen collected by Luis Ruedas at 2120 m elevation from an area approximately 40 km ESE of Gandang Dewata in Rindingallo, of the west-central area of endemism (fig. 1; table 3). DIAGNOSIS: A large (tables 2, 12), stocky shrew (fig. 17) with chocolate dorsal pelage (more reddish brown in MSB 93104 from Rindingallo), slightly grayer ventral pelage, and an unusually thick tail (fig. 33B). The dorsal hairs are dark gray at the base, with the overall pelage color determined by the browner approximately 1 mm tip. The tips of ventral hairs are a paler brown. The tail is shorter than head-and-body length (fig. 9) and holds conspicuous bristles spread along nearly its entire length (fig. 33B). The bristles are pigmented proximally for roughly half their length in the series from Mt. Gandang Dewata, but only for approximately 1 mm on the specimen from Rindingallo (MSB 93104). The tail varies from pale brown to dark brown dorsally and is slightly paler on the ventral surface. The overall color of the tail is largely determined by the many applied hairs that cover the tail scales. The feet are similar in color to the tail, dorsally and ventrally and both the tail and feet are slightly paler than the dorsal pelage. The feet are small relative to body mass, but not body length (fig. 17). The interdigital pads are exceptionally prominent, but the thenar and hypothenar are not unusual (fig. 33B). The pelage is unusually thick, with hairs at the middorsum approximately 8���10 mm long. The skull is large and robust, with a broad interorbital region (figs. 10, 34B). The rostrum is long relative to skull length (fig. 10; table 12). From a dorsal view, the braincase appears narrow, largely from the effect of the broad interorbital region. In dorsal view, the anteriorly converging lines formed by the sinus canal, interorbital margin, and rostrum above the maxillary process are quite straight. In ventral view, the rostrum is TABLE 10 Results of Principal Components Analysis of Craniodental Measurements of the Thick-Tailed Group of Crocidura a Table entries for variables are component loadings. narrow relative to the broad posterior palate. The molar row is robust (fig. 34B). COMPARISONS: Crocidura caudicrassa is larger (as estimated from skull length) than most other species of shrew on Sulawesi. The exceptions are C. elongata and C. quasielongata of the Elongata Subgroup, C. nigripes of the Ordinary Group, and C. rhoditis of the Rhoditis Group. Among these relatively large animals, C. caudicrassa is much stockier than C. nigripes and all members of the Long-Tailed Group (fig. 17; table 2). Only C. rhoditis has a body form nearly as robust, but it is substantially paler in pelage and skin color, particularly on the feet, and has a longer hind foot and thinner tail than C. caudicrassa (fig. 9; table 2). Crocidura caudicrassa could be confused with C. nigripes, despite its stockier body. However, C. caudicrassa differs by having a wider interorbital region relative to both braincase breadth and skull length and a less robust dentition than C. nigripes. Crocidura caudicrassa could also be mistaken for C. brevicauda, the only other member of the Thick-Tailed Group, but the latter has a less stocky body form, less prominent interdigital pads, shorter skull length, narrower rostrum and interorbital region, lesser braincase height, and less elongate interorbital region (table 12). The most distinctive feature of C. caudicrassa is its thick tail, which has no equal among Sulawesi���s Crocidura, but is approached by the somewhat thick tail of C. brevicauda (fig. 33). The pelage of C. caudicrassa is thick���only those of C. brevicauda and C. musseri, the latter of which is much smaller and does not have a particularly thick tail, are comparable. COMMENTS: We tested species limits between the two Thick-Tailed species using BPP on a small dataset containing 13 Crocidura caudicrassa and two C. brevicauda. Twelve of the C. caudicrassa specimens lack three of the five loci in this alignment, and thus it is only 54% complete. Nevertheless, BPP delimited these two species with posterior probability of 1.0 in all replicates. The area around Mt. Gandang Dewata is an expansive region of montane habitat that is almost entirely unexplored by mammalogists. TABLE 11 Results of Principal Components Analysis of External Measurements of the Thick-Tailed Group of Crocidura a Table entries for variables are component loadings. Although we describe Crocidura caudicrassa as a montane endemic, it may have a somewhat larger geographic range in this area. The single specimen from Rindingallo (~ 40 km from Mt. Gandang Dewata) hints at this possibility. We inferred a sister relationship between Crocidura caudicrassa and C. brevicauda in our analyses of UCEs (figs. 7, 8) and nuclear exons (supplementary data S 6), but not in our analyses of mitochondrial DNA (figs. 4, 5). These two phenotypically similar species each appear to be montane endemics restricted to neighboring areas of high elevation, and thus we suspect that our UCE inferences reflect the correct relationship. Jukes-Cantor cytochrome b distances between these two species averaged 0.12, close to the mode of interspecific divergences among Sulawesi shrews and more than twice the median of intraspecific differences (fig. 6; supplementary data S 4). Their morphological differences and presumed isolation by lowland habitats between Mts. Gandang Dewata and Latimojong further support their distinction. SPECIMENS EXAMINED: Mt Gandang Dewata (MZB 34792���34798, 34801���34805), Rindingallo, Tana Toraja (MSB 93104).
Published as part of Esselstyn, Jacob A., Achmadi, Anang S., Handika, Heru, Swanson, Mark T., Giarla, Thomas C. & Rowe, Kevin C., 2021, Fourteen New, Endemic Species Of Shrew (Genus Crocidura) From Sulawesi Reveal A Spectacular Island Radiation, pp. 1-109 in Bulletin of the American Museum of Natural History 2021 (454) on pages 69-71, DOI: 10.1206/0003-0090.454.1.1, http://zenodo.org/record/5788835
Databáze: OpenAIRE
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