Crocidura microelongata, 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 : 33-35

Crocidura microelongata , new species

LSID: urn:lsid:zoobank.org:act:015EFE9D-8AAC-433D-B563-DD8855C43B00

Crocidura elongata Ruedi, 1995: 251 .

Misidentification.

HOLOTYPE: MZB 43000 (= FMNH 213426 ), an adult male, collected on 1 March 2011 by J.A. Esselstyn. The specimen comprises a study skin, cleaned skull and skeleton, and frozen tissue samples. External measurements from the holotype are 206 mm × 111 mm × 20 mm × 10 mm = 12.5 g. The voucher specimen and a tissue sample will be permanently curated at MZB, with another tissue sample retained at FMNH. TYPE LOCALITY: Indonesia, Sulawesi Selatan, Enrekang, Buntu Bato, Latimojong Village , Karangan , Mt. Latimojong , Bantanase ; 3.40755° S, 120.0078° E, 2050 m.

ETYMOLOGY: We combine “micro” with “elongata” because this species looks like a small version of C. elongata .

GEOGRAPHIC DISTRIBUTION: This species is broadly distributed across western portions of the west-central area of endemism of Sulawesi. We identified populations from Mt. Latimojong, South Sulawesi Province; Mt. Gandang Dewata, West Sulawesi Province; and Mts. Torompupu and Rorekatimbo, Central Sulawesi Province ( fig. 16 ). Recorded from approximately 700 m on Mt. Latimojong to 2600 m on Mt. Gandang Dewata. Most specimens are from areas> 1500 m ( fig. 13 ; table 3 ).

DIAGNOSIS: Crocidura microelongata is a somewhat large Crocidura with a long tail and long, slen- der hind feet and skull ( tables 2 , 5 ). The dorsal pelage is gray-brown overall, with individual hairs having a gray-brown base and brown tip ( fig. 14D ). The ventral pelage is more silver, comprising individual hairs with a dark gray base and silver tip. The mystacial vibrissae are dark proximally for a third of their length but white distally. The hind feet are long in absolute terms and relative to head-andbody length ( figs. 9 , 17 ). Dorsally, the feet are brown, abruptly transitioning to pinkish white near the base of the phalanges (in some specimens, it is a gradual transition). Ventrally, the hind feet are nearly white, but brown pigment is present around the lateral, posterior margin of the hind foot and around the base of the thenar and hypothenar pads ( fig. 14D ). In some specimens, the 1st and 4th interdigital pads are also pigmented around the base. The palmar surface is entirely pinkish white. The claws are translucent. The tail is subtly bicolored, with a brown dorsum and pale brown venter. Tiny applied hairs are present along the entire length of the tail, but they are barely visible to the naked eye along most of the length of the tail ( fig. 14D ). These hairs are slightly longer and white near the tip of the tail, creating a very small distal white tuft. In a minority of specimens, the integument is also white for the distal ≤ 20 mm of the tail. The tail bristles that are common at the base of the tail of many Crocidura are nearly absent in this species ( fig. 14D ). The skull is somewhat long and slender, with a tapering interorbital region, and moderately robust dentition ( fig. 18B ). The braincase is dorsoventrally inflated and bulges outward in the parietal region as compared with the more posterior interparietal. Relative to skull length the rostrum is quite short ( fig. 10 ). The braincase is somewhat narrow relative to skull length, but the interorbital region is wide ( fig. 10 ).

COMPARISONS: This species is readily distinguished by its ratio of tail length to head-and-body length ( fig. 9 ; table 2 ) from all Crocidura species on Sulawesi except other members of the Long-Tailed Group. Within the Long-Tailed Group, C. caudipilosa is smaller and has a much hairier tail, shorter hind foot, paler pelage, and lower relative interorbital width (IOW/CIL) but greater relative braincase breadth (BB/CIL) ( figs. 9 , 10 ). Within the Elongata Subgroup, C. microelongata has a smaller body size, shorter tail, shorter and slightly darker hind feet, and shorter skull than C. elongata and C. quasielongata ( fig. 12 ; table 5 ). The thenar pad on the hind foot is shorter than in C. elongata , but comparable to that of C. quasielongta ( fig. 14 ). Although the skull is shorter, its breadth is similar to that of the other two species, whether measured at the braincase, interorbital area, or rostral region ( figs. 10 , 12 ). The interorbital region, however, is more tapered than in either of the two most similar species ( fig. 18 ). The dentition of C. microelongata is slightly smaller in proportion to the skull than in either C. elongata or C. quasielongata ( fig. 18 ).

COMMENTS: Although we have not examined the specimens Ruedi (1995) identified as Crocidura elongata from Mt. Rorekatimbo (IZEA 4365 and 4396), a published cytochrome b sequence from IZEA 4396 is indistinguishable from mitochondrial sequences we obtained from Mt. Rorekatimbo samples of C. microelongata . Our mitochondrial gene trees placed C. microelongata as either sister to the other 19 species that make up Sulawesi’s endemic radiation (all species except C. nigripes ) or to all members of the endemic radiation except C. musseri . However, statistical support for these hypotheses was nonexistent ( fig. 4 ) or modest ( fig. 5 ). Our analyses of nuclear DNA placed C. microelongata as part of the basal comb with no clear sister relationship ( figs. 7 , 8 ; supplementary data S6). See the next account for results of nuclear DNA species delimitation analyses.

SPECIMENS EXAMINED: Mt. Gandang Dewata ( MZB 34736–34741 , 34743–34745 , 34748 , 34749 , 34751 , 34753 , 34755–34757 , 38463 , 38472 , 38473 ; FMNH 218544–218547 , 218584 , 218593– 218603 , 218969 , 218972 ; NMV Z21764 ), Mt. Latimojong ( MZB 40935 , 40937 , 40938 , 43000 ; FMNH 212990–213005 ; MVZ 237567 , 237569– 237572 , 237594 , 238121 ; NMV C38534 ), Mt. Rorekatimbo ( FMNH 213146–213162 , 213164– 213173 , 213435 , 213436 ), Mt. Torompupu (MZB 43013 , 43014 ; NMV C40139 ).

Figures

FIG. 16. Map of Sulawesi showing localities sampled for shrews. Colored areas enclose localities with known records of members of the Elongata Subgroup. Although we excluded Pinedapa from the estimated geographic ranges, we suspect the two USNM specimens referred to Crocidura elongata by Miller and Hollister (1921) from this site represent C. microelongata.

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. 14. 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 four members of the Long-Tailed Group: A, Crocidura caudipilosa, LSUMZ 36940; B, C. quasielongata, FMNH 218551; C, C. elongata, LSUMZ 39009; and D, C. microelongata, FMNH 212998. Scale bars represent 5 mm and apply to their nearest images within each panel. The thenar (T) and hypothenar (H) pads are labeled on panel B.

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. 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. 18. Images showing dorsal, ventral, and lateral views of the skull and lateral and occlusal views of the dentary of the three members of the Elongata Subgroup: A, Crocidura elongata, LSUMZ 39259; B, C. microelongata, FMNH 213426; and C, C. quasielongata, LSUMZ 36939.

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.12. Box plots of skull measurements useful for distinguishing species of the Elongata Subgroup. 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.

FIG. 4. Maximum-likelihood estimate of the gene tree of Sulawesi Crocidura derived from an alignment of 851 individuals and 1111 characters from the mitochondrial gene cytochrome b. Bootstrap support is shown along branches. Clades corresponding to species are collapsed for ease of presentation. Tips are labeled with the species name, the number of tips (T), and number of localities (L), as labeled in figure 1, and the maximum intraspecific (MI) Jukes-Cantor distance calculated from a reduced alignment. Two species are paraphyletic and their respective, within-clade MI values are shown separately. For species described by Miller and Hollister (1921), the holotype or paratypes are included for C. elongata, C. lea, and C. rhoditis. Branch lengths between C. nigripes and other taxa are shortened for presentation. See supplementary data S2 for the full tree.

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.

Tables

TABLE 5 Descriptive Statisticsa for Craniodental Measurements (mm) for Species of the Long-Tailed Group of Sulawesi Crocidura

	C. caudipilosa	C. elongata	C. microelongata	C. quasielongata
Condyloincisive length	20.76 ± 0.624 (19.54–22.2) 44	24.35 ± 0.502 (23.15–25.46) 44	21.9 ± 0.749 (20.3–23.14) 35	24.25 ± 0.663 (22.32–25.23) 40
Braincase breadth	9.46 ± 0.232 (9.0–9.99) 44	9.73 ± 0.263 (9.16–10.22) 42	9.59 ± 0.229 (8.9–10.12) 33	9.81 ± 0.272 (9.26–10.48) 40
Interorbital width	4.47 ± 0.151 (4.1–4.84) 44	5.04 ± 0.17 (4.67–5.35) 44	5.01 ± 0.182 (4.69–5.35) 33	5.01 ± 0.179 (4.63–5.45) 41
Rostral length	8.32 ± 0.313 (7.59–9.05) 44	9.69 ± 0.276 (9.16-10.16) 44	8.59 ± 0.263 (7.91–9.03) 33	9.79 ± 0.307 (8.71–10.27) 41
Postpalatal width	3.77 ± 0.125 (3.52–4.05) 44	4.33 ± 0.13 (4.1–4.64) 44	4.21 ± 0.118 (4.0–4.48) 33	4.41 ± 0.156 (4.1–4.8) 41
Rostral width	2.92 ± 0.146 (2.63–3.22) 44	3.22 ± 0.116 (2.98–3.47) 44	3.03 ± 0.163 (2.62–3.4) 35	3.29 ± 0.178 (3.04–3.74) 41
Postpalatal length	9.44 ± 0.321 (8.82–10.24) 43	11.1 ± 0.265 (10.44–11.84) 44	9.89 ± 0.329 (9.18–10.44) 35	11.0 ± 0.387 (10.29–11.75) 40
Condyle to glenoid fossa	8.25 ± 0.214 (7.89–8.76) 44	9.68 ± 0.211 (9.24–10.09) 44	8.85 ± 0.316 (8.17–9.36) 35	9.38 ± 0.26 (8.88–9.93) 40
Upper toothrow length	9.07 ± 0.283 (8.49–9.66) 44	10.6 ± 0.261 (10.07–11.15) 44	9.46 ± 0.296 (8.78–9.88) 35	10.6 ± 0.30 (9.65–11.03) 41
P4 to M3 length	4.77 ± 0.15 (4.44–5.07) 44	5.82 ± 0.154 (5.42–6.14) 44	5.28 ± 0.179 (4.95–5.62) 35	5.86 ± 0.195 (5.21–6.15) 41
M2 to M2 labial width	5.79 ± 0.194 (5.42–6.26) 44	6.9 ± 0.251 (6.38–7.37) 44	6.32 ± 0.182 (5.93–6.69) 35	6.78 ± 0.181 (6.45–7.1) 41
Palatal width	2.46 ± 0.123 (2.2–2.75) 44	2.68 ± 0.125 (2.44–3.03) 44	2.58 ± 0.1 (2.4–2.84) 35	2.69 ± 0.138 (2.42–2.96) 41

a The sample mean ± one standard deviation, the observed range in parentheses, and the sample size.