Asthenodipsas stuebingi, Quah & Grismer & Lim & Anuar & Imbun, 2019

Quah, Evan S. H., Grismer, L. Lee, Lim, Kelvin K. P., Anuar, M. S. Shahrul & Imbun, Paul Y., 2019, A taxonomic reappraisal of the Smooth Slug Snake Asthenodipsas laevis (Boie, 1827) (Squamata: Pareidae) in Borneo with the description of two new species, Zootaxa 4646 (3), pp. 501-526 : 504-506

publication ID 10.11646/zootaxa.4646.3.4

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scientific name

Asthenodipsas stuebingi

sp. nov.

Asthenodipsas stuebingi sp. nov.

Sabah Mountain Smooth Slug Snake

Figs. 2 View FIGURE 2 & 3 View FIGURE 3 .

Amblycephalus laevis View in CoL (in part): Boulenger 1896: 441 & 442; de Rooij 1917: 276.

Amblycephalus vertebralis View in CoL (in part): Loveridge 1938: 43.

Asthenodipsas laevis (in part): Das 2006: 007, 2010: 344; Grossmann & Tillack 2003: 188; Stuebing et al. 2014: 85.

Internatus laevis: Malkmus et al. 2002: 342 & 343, Figs, 337 & 338.

Pareas laevis: Malkmus 1996: 293 ; Manthey & Grossmann 1997: 377, Abb. 284; Stuebing 1991: 330 & 331 (in part); Stuebing & Inger 1999: 87 (in part); Haile 1958: 766 (in part).

Holotype. Adult female, SP 04679 collected by Paul Yambun Imbun, Fred Tuh Yit Yu and Safrie on 25 March 2009 from Minduk Sirung (Alab–Mahua trail), Crocker Range Park, Sabah, East Malaysia (estimated: N 5.823240, E 116.347238, 1859 m a.s.l.). GoogleMaps

Paratypes. Adult male (SP 04806) collected by Siti Azizah Kusop, Junaidi Ais and R., Adzmie on 26 October 2014 from Kampung Desa Aman , Kundasang (estimated: N5.988087, E 116.570162, 1341 m a.s.l.) GoogleMaps . Adult female ( ZMB 65429) collected by Rudolf Malkmus and Andreas N ӧllert in August 1994 on Kamborangoh Road , Mount Kinabalu, Sabah, West Malaysia (estimated: N6.0292, E116.5473, 1854 m a.s.l.) GoogleMaps . Adult male ( MCZ R43591) collected by John A. Griswold Jr. in 1937 from Kadmayan R, near Kiau , Sabah, West Malaysia (estimated: N6.029788, E 116.489732, 971 m a.s.l.) GoogleMaps .

Diagnosis. Morphological analyses of the four specimens from the highlands of Sabah confirms the placement of this population in the genus Asthenodipsas based on the combination of the following characters: smooth dorsal scales; absence of preoculars and suboculars; one or more supralabials in contact with the eye; a single anterior inframaxillary, followed by two or three pairs of inframaxillaries which are wider than long ( Grossmann & Tillack 2003). Asthenodipsas stuebingi sp. nov. can be differentiated from its congeners by the following combination of characters: a maximum SVL of 557 mm; 15/15/15 dorsal scale rows; 165–175 ventrals; 35–47 subcaudal scales; one or two postoculars; 2(+0–1)+2 temporals; six supralabials, 3 rd & 4 th touching the eye; 4–6 infralabials, 2 nd or 3 rd pair in contact; a sharp vertebral keel; dorsum of adults beige to brown and overlain with 30–42 irregularly-shaped, rhomboidal dark brown bands beginning posterior to dark patch on the neck that and extends the length of body and tail and onto lateral edges of the ventral scales to form spots, but not encircling body; a narrow, light-coloured vertebral stripe; throat and ventrals beige to yellow and mottled with small, dark spots; head whitish to light-brown with dark speckling on the snout and crown; and iris and pupils black ( Table 4 View TABLE 4 , 5 View TABLE 5 & 6 View TABLE 6 ; Fig. 2 View FIGURE 2 & 3 View FIGURE 3 ).

Description of holotype. Adult female SVL 557 mm and Tal 62 mm; rostral as wide as high; head somewhat bulbous and elongate in shape, longer than wide; nasals undivided; internasals shorter than prefrontals; posterior margin of prefrontals contact eye; frontal hexagonal, slightly wider than long; loreals present, longer than wide; supraoculars subpentagonal, approximately half the length and half the width of frontal; preoculars absent; upper and lower postoculars present on right side of head, lower postocular extending to below orbit; single postocular on left side of head, lower margin extending to below orbit; suboculars absent; supralabials 6/6 with 3rd and 4th contacting orbit and 6th elongate; temporals 2(+1)+2/2+2, i.e. on left side of head there are two anterior temporals and two posterior temporals but between lower anterior and lower posterior temporal is an additional scale resulting in two upper temporals and three lower temporals; mental triangular wider than long; anterior inframaxillary pentagonal, in contact with infralabials 1–3; two pairs of posterior inframaxillaries following anterior inframaxillary, first pair of posterior inframaxillaries slightly oval, rhomboid-shaped, second pair more heaxagonal, elongated; infralabials 6/6 with 3 rd pair in medial contact. Body long, bulky, laterally compressed, bearing a prominent keel-shaped vertebral region; dorsal scales smooth, in 15/15/15 rows, vertebrals slightly enlarged; 170 ventrals; 36 divided subcaudals; cloacal scute entire; tail tapering to a point.

Colouration in preservation ( Fig 2A & B View FIGURE 2 ). The ground colour of the head, body and tail is beige with dark speckling. The speckling is heavier on the dorsum nearer to the vertebral scale rows and lightens up on the flanks. The top of the head is also heavily speckled and the rostral, nasal, loreal, postoculars, supralabials, mental, inframaxillaries and infralabials are mottled with dark spots. On the neck is a dark patch starting from the nape, behind the posterior margin of the jaw, extending to approximately the position of the 11 th ventral. The dark patch starts as a narrow stripe on the 4 th & 5 th dorsal scale rows, gradually widens to dorsal scale rows 1–5, and does not cross the vertebral scales or meet on the ventrals. Starting behind the dark neck patch are 42 dark, rhomboidal bands ranging from 1–2 dorsal scales in length along the body and tail. The venter is yellow and bears, dark lateral blotches from the extensions of the dorsal bands that meet the ventral scales as well as scattered dark spots between them. The thin vertebral stripe is light-yellow.

laevis group. Abbreviations are in the Materials and methods. A. jamilinaisi A. stuebingi A. laevis A. laevis Thai-Ma- A. laevis A. laevis

sp. nov. sp. nov. Borneo lay Peninsula Java Sumatra Variation ( Table 4 View TABLE 4 ; Fig 2 View FIGURE 2 & 3 View FIGURE 3 ). The paratypes closely resemble the holotype in overall external morphology, colouration, and pattern. All paratypes have a slightly darker ground colour than the holotype and a larger dark neck patch. In SP 04806 the markings from the dark neck patch extend further onto the edges of the ventrals, leaving a narrow, light-coloured median stripe on the underside of the neck and the tail is more heavily mottled. Paratypes ZMB 65429 and MCZ R43591 also have fewer infralabials than the holotype (4–5 vs. 6) and the second instead of the third pair are in contact. Variation in scale counts and size measurements within the type series are shown in Table 4 View TABLE 4 .

Comparison. Asthenodipsas stuebingi sp. nov. can be differentiated from Aplopeltura boa by its higher number of mid-dorsal scale rows (15 vs. 13) and divided subcaudals ( de Rooij 1917; Grossmann & Tillack 2003; Stuebing et al. 2014). Asthenodipsas stuebingi sp. nov. can be differentiated from members of the genus Pareas by their possession of preocular and subocular scales (absent vs. present), supralabials in contact with orbit (3 rd & 4 th contact orbit vs. no supralabials in contact with orbit) and anterior single inframaxillary (present vs. absent) ( Grossmann & Tillack 2003). Asthenodipsas lasgalenensis , A. tropidonotus and A. vertebralis can be differentiated from the new species by their higher number subcaudals (54–77 vs. 35–47), pairs of infralabials in contact (1 st vs. 3 rd) and more pairs of posterior inframaxillaries (three vs. two). In addition, A. vertebralis and A. tropidonotus can be differentiated from A. stuebingi sp. nov. by their higher number of ventrals (195–215 vs. 165–175). Adult A. lasgalensis can also be differentiated from A. stuebingi sp. nov. by their dorsal colour pattern that is solid dark brown to black and their whitish labials versus a beige to brown dorsum with dark-bands and a dark patch on the neck in the latter ( Loredo et al. 2013). From Bornean populations of A. malaccana to which it is most similar in colour pattern, A. stuebingi sp. nov. can be differentiated by a lower number of supralabials (6 vs. 7–8) (Chan-ard et al. 2015; Das 2010; de Rooij 1917; Stuebing et al. 2014). From A. laevis to which it was previously confused, A. stuebingi sp. nov. can be differentiated by its larger adult length, (Max SVL 557mm vs. 373mm), dorsal scales rows (15/15/15 vs. 15/15/13) and sharp vertebral keel (present vs. absent) ( Figs. 3F View FIGURE 3 & 4F View FIGURE 4 ) ( Tables 2–6 View TABLE 2 View TABLE 3 View TABLE 4 View TABLE 5 View TABLE 6 ). A. stuenbingi sp. nov. can be differentiated from A. jamilinaisi sp. nov. by its lower number of subcaudals (35–47 vs. 52–53), lower number of ventrals in males (165 vs. 173–175), size of vertebral scales (slightly enlarged vs. greatly enlarged), colour pattern (light-coloured head and dorsum with a dark neck patch and distinct bands vs. dark overall colouration of dorsum with muted banding) and body form (robust and stout vs. gracile and laterally compressed) ( Tables 4–6 View TABLE 4 View TABLE 5 View TABLE 6 ). A key to the family Pareidae of Borneo is presented below.

Distribution ( Fig. 8 View FIGURE 8 ). Asthenodipsas stuebingi sp. nov. is only known from the highlands of Sabah, East Malaysia at Mount Kinabalu, Kundasang and the Crocker Range. It is likely to range further throughout the island and found in similar upland habitats in Sarawak, Malaysia and Kalimantan, Indonesian Borneo.

Etymology. The specific epithet stuebingi is a patronym in honour of Robert B. Stuebing for his contributions to the field of herpetology in Borneo, especially on the study of snakes.

Natural History. Asthenodipsas stuebingi sp. nov. is a montane species that so far has only been found on the highlands of Sabah from 900–2000 m a.s.l.. This is in contrast to its congener A. laevis that is widely distributed in Borneo and recorded from many lowland localities up to 1150 m in elevation ( Stuebing et al. 2014). At some locations such as the Crocker Range, both species occur (SP 04476, SP 04570 & SP 04679; see Table 5 View TABLE 5 ). Similar to other species of slug snakes, A. stuebingi sp. nov. is nocturnal. It is reportedly both terrestrial and arboreal ( Malkmus et al. 2002). Malkmus et al. (2002) reported finding a specimen crossing the road at night in rainy weather and another specimen in a bush approximately 1m above the ground. The paratype ZMB 65429 was also collected at night fol- lowing light rains at approximately 22:00 h. A specimen was observed at 09:00 h close the power station of the Kinabalu park headquarters along Kamborangoh road (Andreas N ӧllert in litt. 2018). When threatened, the snakes roll themselves up into tight coils and remain motionless ( Fig. 3D & E View FIGURE 3 ) — a behaviour observed in Aplopeltura boa ( Jablonski & Hegner 2016) . Asthenodipsas stuebingi sp. nov. presumably feeds on snails or slugs like other mem- bers of the family and nothing is known about the reproductive biology of the species.


Museum für Naturkunde Berlin (Zoological Collections)


Museum of Comparative Zoology














Asthenodipsas stuebingi

Quah, Evan S. H., Grismer, L. Lee, Lim, Kelvin K. P., Anuar, M. S. Shahrul & Imbun, Paul Y. 2019

Asthenodipsas laevis

Stuebing, R. B. & Inger, R. F. & Lardner, B. 2014: 85
Grossmann, W. & Tillack, F. 2003: 188

Internatus laevis:

Malkmus, R. & Manthey, U. & Vogel, G. & Hoffmann, P. & Kosuch, J. 2002: 342

Pareas laevis: Malkmus 1996: 293

Stuebing, R. B. & Inger, R. F. 1999: 87
Manthey, U. & Grossmann, W. 1997: 377
Malkmus, R. 1996: 293
Stuebing, R. B. 1991: 330
Haile, N. S. 1958: 766

Amblycephalus vertebralis

Loveridge, A. 1938: 43

Amblycephalus laevis

de Rooij, N. 1917: 276
Boulenger, G. A. 1896: 441
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