Dibamus manadotuaensis Koppetsch & Böhme & Koch 2019, new species
Creators: name: Koppetsch, Thore
name: Böhme, Wolfgang
name: Koch, André
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Dibamidae
Dibamus
Dibamus manadotuaensis

description: Dibamus manadotuaensis, new species
Figs. 2–7
urn:lsid:zoobank.org:act: 8817F788-72D2-4983-9DF6-CC753A829596
Holotype: MZB Lace. 14728 (ex-ZFMK 95558, Figs. 2–7), a male collected by N. Schneider on Pulau (= island) Manado Tua off the northern tip of the Minahassa Peninsula of Sulawesi, Indonesia, donated to the ZFMK in August 1991.
Paratypes: ZFMK 95559 (Figs. 4B, 7B), an adult female, and ZFMK 95560, an adult male, with the same locality and collecting data as the holotype.
Diagnosis: Dibamus manadotuaensis sp. nov. can be distinguished from all other congeners by the following combination of characters: maximum snout-vent length 135 mm; tail length up to 14.2 mm (i.e., 1 2–13 % of SVL); labial and nasal sutures present and complete; no enlarged sublabial scale; four (three) postoculars; four to six scales on posterior edge of infralabial; 26–28 midbody scale rows; 30–33 transverse scale rows posterior to head; 25 transverse scale rows anterior to vent; 218–232 ventral scales; 39 subcaudal scales; relative size of frontal to frontonasal 0.68–0.73; relative size of interparietal to surrounding scales 0.67–1.43; 132–135 presacral vertebrae; and 21–24 postsacral vertebrae. Light bands on the body are missing (Table 1).
Description of holotype: Snout-vent length (SVL) 109 mm; tail length (TL) 14 mm (13% of SVL); head nearly as long (HL 3.9 mm) as wide (HW 4.0 mm); eye to snout distance (ES) 2.3 mm; eye to nostril distance (EN) 1.8 mm; internasal distance (IN) 1.0 mm; interorbital distance (IO) 2.4 mm; snout bluntly rounded, distinctly conical (IN/IO ratio 0.42), projecting beyond lower jaw; nostril laterally oriented, oval, situated closer to tip of snout than to orbit (EN/ES ratio 0.78); rostral pad with a large number of evenly distributed sensory papillae; nasal sutures complete, extending from ocular to nostril; labial sutures complete, extending from anterior part of nasal suture to mouth; posterior border of rostral deeply curved; both frontonasal (FNSL/FNSW = 0.29) and frontal (FSL/FSW = 0.5) wider than long; frontonasal 1.42 times wider than frontal; frontonasal posteriorly bordered by five scales including frontal; two ocular scales; interparietal single, not enlarged, narrower than frontonasal and frontal, posteriorly bordered by four slightly smaller nuchal scales; four postoculars, with one postocular scale contacting frontal on each side; supralabial single, elongated, bordering ocular ventrally; infralabials lanceolate, separated by a smaller, trapezoid mental; six scales bordering posterior edge of infralabial; ear opening absent; eyes dimly visible through ocular; ocular scale larger than anterior body scales (Fig. 3); tongue short, not bifurcated; fourteen teeth in the lower and upper jaw, respectively, each with a slightly curved tip (Fig. 6).
Body worm-like, almost cylindrical, midbody width (BW) 4.4 mm (BW/SVL ratio 0.04); head slightly distinct from neck; tail short (TL/SVL ratio 0.13), tip rounded, not bulbous, wider than rest of the tail (Fig. 2); body scales smooth, subcycloid, including near preanal region; 27 midbody scale rows; 30 transverse scale rows posterior to head; 25 transverse scale rows anterior to vent; 218 ventral scales; 39 subcaudal scales; 134 presacral vertebrae; 24 postsacral vertebrae (Fig. 5); tail complete; rudimentary flap-like hind limbs present, measuring 1.6 mm in length, covered with four paired scales, and terminating in a single scale with a rounded tip (Fig. 4A); pair of enlarged scales on preanal region, separated by a median scale, overlapping those on sides; preanal pores absent; postanal scales not reduced, compared to body scales.
Colouration in life: Unknown.
Colouration in preservation: Dorsum dark brown to grey-brown, unpatterned (Fig. 2); venter slightly paler than dorsum; scales of head and neck dark brown, each edged by a brighter border; remaining body scales, particularly on the ventral side, light brown with darker marbling; nuchal and body bands absent; tip of snout, supralabials, throat, hind limbs and preanal region slightly lighter, cream coloured (Fig. 4A).
Variation. In the female paratype ZFMK 95559 the two flap-like hind limbs that are present in the two males, as is typical for dibamids, are lacking (Fig. 4B). The absence of hind limbs correlates with the reduction of osseous limb structures in the female specimen. Fibula and tibia are missing as is visible in the micro-CT images (Fig. 7B). In addition, this specimen shows a slightly higher number of transverse scale rows posterior to head (33 vs. 30), a lower number of scales bordering the posterior edge of the infralabial (5 vs. 6), a higher number of ventrals (232 vs. 218), and a greater snout-vent length (115 mm vs. 109 mm). The male paratype ZFMK 95560 is similar to the holotype in morphology except for the missing tail probably caused by damage during collecting or by a predator. The specimen exhibits a slightly higher number of ventrals (223 vs. 218), but shows a lower number of scales bordering the posterior edge of the infralabial (4 vs. 6) and possesses only three postoculars on the right side (see Table 1).
Comparisons. In possessing four postoculars, Dibamus manadotuaensis sp. nov. can be distinguished from the following congeners that possess three or fewer postoculars: D. alfredi Taylor 1962, D. bogadeki Darevsky 1992, D. booliati Das & Yaakob 2003, D. bourreti Angel 1935, D. celebensis, D. dalaiensis Neang et al. 2011, D. deharvengi Ineich 1999, D. dezwaani Das & Lim 2005, D. floweri Quah et al. 2017, D. greeri Darevsky 1992, D. ingeri Das & Lim 2003, D. kondaoensis Honda et al. 2001, D. leucurus (Bleeker 1860), D. montanus Smith 1921, D. nicobaricum (Steindachner 1867), D. novaeguineae Duméril & Bibron 1839, D. smithi Greer 1985, D. somsaki Honda et al. 1997, D. tebal Das & Lim 2009, D. tiomanensis Diaz et al. 2004 and D. vorisi Das & Lim 2003.
The lower maximum snout-vent length of D. manadotuaensis sp. nov. (135 mm) separates it from D. seramensis Greer 1985 (203 mm) and D. taylori Greer 1985 (169 mm). In addition, D. manadotuaensis sp. nov. can be distinguished from D. seramensis by its lower number of mid-body scale rows (26–28 vs. 33) and the lower number of subcaudal scales of the new species (39 in both sexes) separates it from D. taylori (males: 41–55; females: 41–52) (see Table 2).
22 dezwaani 2 4 22? 37?? 123.1 12.75 1 floweri 1(2) 4(2) 21 46 23 1.1–1.5 1.3–1.8 112 11.4–15.2
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Etymology. The specific epithet manadotuaensis refers to the little volcanic island of Manado Tua, the type locality and only known distribution of the new species.
Distribution. At present, Dibamus manadotuaensis sp. nov. is only known from the type locality Pulau (= island) Manado Tua, Northern Sulawesi, Indonesia, which belongs to the Bunaken Marine National Park (Fig. 1). It is likely that this species also inhabits the other surrounding islands off the coast of Manado, the capital of Sulawesi Utara Province.
Natural history. While nothing is known about behaviour or ecology of D. manadotuaensis sp. nov., it seems likely that it resembles those of other dibamids from insular Southeast Asia. All known species show a fossorial lifestyle and occur in rainforest leaf litter and soil (Das & Lim 2009). They feed on small arthropods and earth worms (Zug et al. 2001). When disturbed a defensive, anti-predator behaviour is reported for several species, such as D. floweri and D. tiomanensis. They flare up their body scales, so that the smooth surface appears to be covered with little bristles, resembling the epidermis of possibly non-palatable earthworms (Diaz et al. 2004; Quah et al. 2017).
description: Published as part of Koppetsch, Thore, Böhme, Wolfgang & Koch, André, 2019, A new species of Dibamus Duméril & Bibron, 1839 (Squamata: Dibamidae) from Pulau Manado Tua, Northern Sulawesi, Indonesia, pp. 331-345 in Zootaxa 4555 (3) on pages 334-342, DOI: 10.11646/zootaxa.4555.3.3, http://zenodo.org/record/2624448