Crocidura baletei, Esselstyn & Achmadi & Handika & Swanson & Giarla & Rowe, 2021

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, Bulletin of the American Museum of Natural History 2021 (454), pp. 1-109 : 57-60

Crocidura baletei , new species

LSID: urn:lsid:zoobank.org:act:6D7C389E-00FB-4D18-B6D9-889279B66FE1

Crocidura “dark lea” Esselstyn et al., 2019: 1715. Informal name.

HOLOTYPE: MZB 43005 (= LSUMZ 36959 ), an adult male, collected by J.A. Esselstyn on 10 March 2013. Specimen consists of a cleaned skull ( fig. 28A ), a fluid-preserved body, and frozen tissues. External measurements from the holotype are: 119 mm × 50 mm × 12 mm × 8 mm = 4.9 g. The voucher and a tissue sample will be permanently curated at MZB, with another tissue sample retained by LSUMZ.

TYPE LOCALITY: Indonesia, Sulawesi Tengah, Toli Toli, Galang, Malangga Selatan , Mt. Dako ; 1.10607° N, 120.93853° E, 1600 m.

ETYMOLOGY: Named in honor of Danilo S. Balete, an accomplished mammal systematist who passed away much too early in 2017. Danny, as he is known, was a tireless collector, whose years of field research in the Philippines built the kind of museum collections needed for comprehensive catalogs of biodiversity. Without the focused, long-term efforts of people like Danny, the type of comprehensive taxonomic research we are attempting here would not be possible.

GEOGRAPHIC DISTRIBUTION: Apparently endemic to montane forests of the north-west area of endemism. We recorded this species only on Mts. Dako and Buliohuto ( fig. 25 ) at elevations around 1600 and 1400 m, respectively ( fig. 13 ). Our sampling efforts at lower elevations (400–600 m; fig. 3 ) on both mountains did not find this species ( table 3 ). Surveys in the mountains west and south of Mt. Dako (i.e., the base of the northern peninsula) and east of Mt. Buliohuto are needed to draw firmer conclusions regarding the geographic distribution of Crocidura baletei .

DIAGNOSIS: Crocidura baletei is a very small shrew ( tables 2 , 8 ) with a brown pelage and skin color, where exposed. Overall, this species is quite uniform in color, with the feet, pinnae, and tail matching the surrounding fur. The venter and dorsum are similarly colored. The pinnae are, however, paler around their lower margin. The mystacial vibrissae are pigmented for about the proximal half of their length, but unpigmented distally. The color of the digits is only slightly paler than that of the rest of the foot ( fig. 27A ). Tail length is shorter than head-and-body length ( fig. 9 ; table 2 ) and bristles are present for approximately three-fourths of tail length. Small, applied hairs are present on the tail, but difficult to see with the naked eye. The skull is short, particularly the rostral portion, relative to the overall body size of the species ( fig. 28 ). Relative to skull length, the skull is broad overall, especially at the braincase ( fig. 10 ). On the upper dentition, I3 (U2) and C (U3) are subequal and the parastyle of P4 is modest ( fig. 28A ).

COMPARISONS: This shrew is much smaller than all other Sulawesi Crocidura outside of the Small-Bodied Group ( fig. 9 ). Within the Small- Bodied Group, C. lea and C. tenebrosa are the only other taxa known from the northern peninsula. Among the tiny shrews of the northern peninsula, C. baletei and C. tenebrosa are more uniform in color than C. lea , with C. baletei being paler (medium brown) than C. tenebrosa (dark brown). Crocidura lea has a paler integument, wherever it is exposed, and it is more strongly bicolored than either C. baletei (somewhat darker) or C. tenebrosa (much darker). Dorsally, the feet of both C. baletei and C. tenebrosa are uniformly dark, whereas the foot color transitions posteriorly from brown at the heel to white or pink digits in C. lea . Similarly, the tails of both C. baletei and C. tenebrosa are not obviously bicolored, and both are darker. Tail bristles are present on approximately three-fourths of the tail length in all three species, but they are much more abundant and longer on the tails of C. baletei and C. tenebrosa than in C. lea ( fig. 27 ). Applied hairs on the tail are also more visible in the two new species than in C. lea . Tail length in C. baletei is slightly shorter than in C. lea , but substantially longer than in C. tenebrosa ( fig. 9 ). On the hind foot, the thenar pad is wider and more prominent than in C. lea , but comparable to that of C. tenebrosa ( fig. 27 ). The skulls of all three species are similar in length, but that of C. baletei is considerably wider than that of C. lea ( figs. 10 , 26 , 30 ). The braincase breadths relative to skull lengths (BB/CIL) are similar in C. baletei and C. tenebrosa , but the interorbital region is relatively wider (IOW/CIL) in C. tenebrosa ( fig. 10 ). Relative rostral length (RL/CIL) is slightly less in C. baletei than in C. tenebrosa ( fig. 10 ). The parastyle of P4 is less prominent in C. baletei than in C. tenebrosa .

COMMENTS: See comments for Crocidura tenebrosa , below.

SPECIMENS EXAMINED: Mt. Buliohuto ( LSUMZ 38264 , 38265 , 38268 , 38270 ; NMV C37777 , C37794 , C37800 ), Mt. Dako ( LSUMZ 36946 , 36951 , 36953 , 36961–36963 , 36965 , 36966 ; MZB 43005 ; NMV C37306 ) .

Figures

FIG. 28. Images showing dorsal, ventral, and lateral views of the skull and lateral and occlusal views of the dentary from the three members of the Small-Bodied Group that are from the northern peninsula:A, Crocidura baletei, LSUMZ 36959; B, C. lea, LSUMZ 38262; and C, C. tenebrosa, LSUMZ 39272.

FIG. 25. Map of Sulawesi showing localities sampled for shrews. Colored areas enclose localities with known records of members of the Small-Bodied Group of Sulawesi Crocidura.

FIG. 13. Elevational records of all species of Crocidura known from Sulawesi. Each point represents a specimen. For specimens associated with a minimum and maximum elevation, we used the center of the given elevational range. Sample sizes are given above the x-axis. Species are grouped according to the species groups used in the text (Thick = Thick-Tailed Group).

FIG. 3. Plot of the elevational distribution of samples from each of the 12 mountains that comprise the bulk of specimens we examined. Each point represents the median elevation of a specimen we examined. The sample distribution from Mt. Gandang Dewata includes specimens from Salu Tiwo (~200 m). The number of specimens used from each mountain is given above the x-axis and the peak elevation of each mountain is shown on the x-axis.

FIG. 27. Images showing the ventral surface of the hind foot and dorsal surfaces of the tail base (approximately 1 cm from rump) and tail tip from the three members of the Small-Bodied Group that are from the northern peninsula: A, Crocidura baletei, LSUMZ 36959 (right hind foot); B, C. lea, LSUMZ 38254 (left hind foot); and C, C. tenebrosa, LSUMZ 39268 (right hind foot). Scale bars represent 5 mm. Within each panel, the upper bar applies to the foot and the lower bar corresponds to both tail images.

FIG. 9. Box plots showing variation in external measurements from all species of Sulawesi shrew. Plots show the median, 1st and 3rd quartiles, the maximum value within 1.5 × interquartile range (distance between 1st and 3rd quartiles; IQR), the minimum value within 1.5 × IQR, and outliers (black circles). Sample sizes are shown along the x-axis. Species are grouped according to the species groups used in the text (Thick = Thick- Tailed Group). All measurements in mm. HBL = head-and-body length.

FIG. 10. Box plots of relative skull measures showing braincase breadth (BB), interorbital width (IOW), and rostral length (RL) divided by condyloincisive length (CIL) and BB divided by IOW for all species of Sulawesi shrew. Plots show the median, 1st and 3rd quartiles, the maximum value within 1.5 × interquartile range (distance between 1st and 3rd quartiles; IQR), the minimum value within 1.5 × IQR, and outliers (black circles). Sample sizes are shown along the x-axis. Species are ordered according to the species groups used in the text (Thick = Thick-Tailed Group).

FIG. 26. Bivariate plots showing A, variation in the condyloincisive length and braincase breadth and B, the first two axes from a principal components analysis of 12 cranial measurements among all members of the Small-Bodied Group. Loadings and variance explained are given in table 9.

FIG. 30. Box plots showing variation in skull width and tail length from species of the Small-Bodied Group on the northern peninsula of Sulawesi. Plots show the median, 1st and 3rd quartiles, the maximum value within 1.5 × interquartile range (distance between 1st and 3rd quartiles; IQR), the minimum value within 1.5 × IQR, and outliers (black circles). Sample sizes are shown along the x-axis. All measurements in mm.