Crocidura parva, 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 : 66-67

Crocidura parva , new species

LSID: urn:lsid:zoobank.org:act:8C7D230C-7F04-4FE0-9896-5921A8574315

HOLOTYPE: MZB 43008 (= MVZ 237577 ), an adult female collected on 18 October 2016 by H. Handika. The specimen is preserved as a study skin, cleaned skull ( fig. 31C ) and skeleton, and frozen tissues. External measurements recorded in the field from the type are: 101 mm × 41 mm × 2 mm × 7 mm = 3.9 g. Hind-foot length for the holotype was erroneously recorded as 2 mm; the true value is almost certainly 12 mm. The voucher specimen and a tissue sample will be permanently curated at MZB, while an additional tissue sample will be retained at MVZ.

TYPE LOCALITY: Indonesia, Sulawesi Selatan, Sinjai, Sinjai Barat, Gunung Perak Village , Mt. Bawakaraeng ; 5.286815° S, 119.961406° E, 1713– 1754 m elevation.

ETYMOLOGY: Parva is Latin (feminine) for “tiny,” used in recognition of the diminutive body size of this species.

GEOGRAPHIC DISTRIBUTION: This animal was extremely abundant on Mt. Bawakaraeng of the south-west area of endemism (South Sulawesi Province; fig. 25 ). We did not encounter it anywhere else and it may be endemic to this region. All specimens were collected between 1700 and 2500 m elevation ( table 3 ). Habitat destruction has eliminated low- and middle-elevation forests in South Sulawesi, which may have altered the natural elevational distribution of this species.

DIAGNOSIS: Crocidura parva is among the smallest shrews on Sulawesi and it has the narrowest average braincase breadth of any species on the island ( tables 2 , 8 ). For a shrew of its head-and-body length, it has a rather delicate build ( fig. 17 ). Crocidura parva has a gray-brown to dark brown pelage, with a slightly grayer venter. The fur is not particularly dense, and individual hairs on the middorsum are only about 3 mm in length, despite all specimens coming from mid to high elevation. Overall, the color of the skin on the feet, ears, lips, and tail match that of the surrounding pelage. The mystacial vibrissae are short (most <10 mm) and pigmented proximally for no more than half of their length. The tail length is short absolutely, and less than head-and-body length ( fig. 9 ; table 2 ). Tail bristles are relatively abundant and are present along about two-thirds of the proximal tail length ( fig. 29C ). The skull is short, but also quite narrow at the braincase, giving it an elongate and dorsoventrally compressed overall appearance. The lambdoidal ridge is indistinct. The width of the interorbital region is middling relative to skull length ( fig. 10 ) and the maxillary process is not prominent. Rostral length forms a relatively small proportion of skull length ( fig. 10 ). The molar row is crowded on the narrow palate ( fig. 31C ). On the upper cheek teeth, the metacone is unusually prominent relative to the protocone, particularly on P4.

COMPARISONS: Crocidura parva is much smaller than all known Sulawesi shrews except other members of the Small-Bodied Group. Externally, C. parva is rather uniform in color, as are C. levicula , C. baletei , and C. tenebrosa , but other species have paler feet than bodies, including C. lea and to a lesser extent, C. mediocris . The overall color of C. parva is slightly darker than C. mediocris , and considerably darker than C. lea . The tail has more bristles than in C. mediocris , but fewer than C. levicula ( fig. 29 ). The pelage is shorter than in other species, except that C. mediocris is similar. The skull of the tiny C. parva is slightly smaller overall than seen in any of the other very small taxa ( table 8 ) and relative rostral length (RL/CIL) is less than in C. mediocris , C. baletei , and C. tenebrosa ( fig. 10 ). Most distinctively, the braincases of the other species are more dorsoventrally inflated, particularly in the case of C. lea . The flat braincase of C. parva is narrower than in all other Small-Bodied species, but the range of values overlaps with those from C. lea , C. levicula , and C. mediocris ( fig. 26 ). Bivariate plots of cranial length versus width and the first two axes from a PCA of 12 cranial dimensions show C. parva to occupy largely distinct morphometric space, but to overlap some with C. lea , C. levicula , and C. mediocris ( fig. 26 ). Finally, in C. parva , on the upper molariform teeth, the protocone is relatively low, compared with those of the other Small-Bodied shrews ( figs. 28 , 31 ).

COMMENTS: We found this species only on Mt. Bawakaraeng, but our nearest sample sites are on Mt. Latimojong ( fig. 25 ), some 215 km away. Much of the intervening habitat between Mts. Bawakaraeng and Latimojong is low elevation and dry, with the lowest area (the Tempe Depression) considered a barrier to many vertebrate taxa. Nevertheless, sampling additional sites in the south-west area of endemism may extend the known range of Crocidura parva . We interpret this probable isolation as additional support for distinguishing C. parva from C. mediocris , which is phenotypically similar. These two species are sister taxa in our mitogenome phylogeny ( fig. 5 ), but each is paraphyletic with respect to the other in our UCE ( figs. 7 , 8 ) and nuclear exon phylogenies (supplementary data S6). Because of the slow evolutionary rate of UCEs and exons, we do not consider this to be strong evidence against their distinction.

We tested species limits in BPP between Crocidura parva and C. mediocris and among C. parva , C. mediocris , and C. normalis . The former analysis employed 20 individuals of each species and the matrix is 95% complete. The second analysis used the same dataset, but with the addition of 36 specimens of C. normalis . This matrix is 94% complete. All analyses supported each species with a posterior probability of 1.

SPECIMENS EXAMINED: Mt. Bawakaraeng ( MVZ 237575 , 237576 , 237578–237581 , 237583 , 237584 , 237600–237609 ; MZB 43008 ; NMV Z57156 , Z56280 , Z56302 , Z56314 , Z56319 , Z56995 , Z57008 , Z57012 , Z57045 , Z57046 , Z57047 , Z57057 , Z57064 , Z57103 , Z57129 , Z57208 ) .

Figures

FIG. 31. Images showing dorsal, ventral, and lateral views of the skull and lateral and occlusal views of the dentary of the three members of the Small- Bodied Group that are not from the northern peninsula: A, Crocidura levicula, FMNH 213362; B, C. mediocris, FMNH 210603; and C, C. parva, MVZ 237577.

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. 17. Box plots showing the length of the hind foot (HF) relative to the head-and-body length (HBL) and the ratio of mass to HBL. 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 along the x-axis according to the species groups used in the text (Thick = Thick-Tailed Group). Lengths are in mm and mass is in grams.

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. 29. Images showing the ventral surface of the left 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 not from the northern peninsula: A, Crocidura levicula, FMNH 213271; B, C. mediocris, FMNH 210566; and C, C. parva, MVZ 237583. Where two scale bars are present within a panel, the upper applies to the foot and the lower to the tail.

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. 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. 5. Maximum likelihood estimate of the mitochondrial gene tree derived from an analysis of 14,007 characters (representing protein-coding and rRNA genes) from 83 samples. Bootstrap support values <95 are shown at nodes. Tips are labeled with the species, locality, and voucher number.

FIG. 7. Estimated species tree from analysis of 3940 ultraconserved element loci in ASTRAL. Samples from Sulawesi are labeled with the species name, locality, and catalog number. Asterisks indicate type specimens from Miller and Hollister (1921). Local posterior probabilities <0.95 are shown. Tip branch lengths are arbitrary.

FIG. 8. Estimated phylogenetic relationships from a maximum likelihood analysis of 983 concatenated ultraconserved elements. Samples from Sulawesi are labeled with the species name, locality, and catalog number. Asterisks indicate type specimens from Miller and Hollister (1921). Ultrafast bootstrap values <95 are shown.