Amblycephalus laevis Boulenger 1896: 441 de Rooij 1917: 276 Amblycephalus vertebralis Loveridge 1938: 43 Asthenodipsas laevis Grossmann & Tillack 2003: 188 Stuebing et al . 2014: 85 Malkmus et al . 2002: 342 Malkmus 1996: 293 Manthey & Grossmann 1997: 377 Stuebing 1991: 330 Stuebing & Inger 1999: 87 Haile 1958: 766 A taxonomic reappraisal of the Smooth Slug Snake Asthenodipsas laevis (Boie, 1827) (Squamata: Pareidae) in Borneo with the description of two new species Quah, Evan S. H. Grismer, L. Lee Lim, Kelvin K. P. Anuar, M. S. Shahrul Imbun, Paul Y. Zootaxa 2019 2019-07-25 4646 3 501 526 Quah & Grismer & Lim & Anuar & Imbun, 2019 Quah & Grismer & Lim & Anuar & Imbun 2019 [151,444,785,812] Reptilia Pareatidae Asthenodipsas Animalia Squamata 3 504 Chordata species stuebingi sp. nov.   Figs. 2& 3.  urn:lsid:zoobank.org:act: 99B2763A-B16E-4320-8176-FC7E311305BA     Amblycephalus laevis(in part):  Boulenger 1896: 441& 442;  de Rooij 1917: 276.    Amblycephalus vertebralis(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. Adultfemale, SP 04679 collected by Paul Yambun Imbun, Fred Tuh Yit Yuand Safrieon  25 March 2009from Minduk Sirung(Alab–Mahua trail), Crocker Range Park, Sabah, East Malaysia(estimated: N 5.823240, E 116.347238,  1859 ma.s.l.).    Paratypes. Adultmale (SP 04806) collected by Siti Azizah Kusop, Junaidi Aisand R., Adzmieon  26 October 2014from Kampung Desa Aman, Kundasang(estimated: N5.988087, E 116.570162,  1341 ma.s.l.).  Adultfemale ( ZMB65429) collected by Rudolf Malkmusand Andreas Nӧllert in  August 1994on Kamborangoh Road, Mount Kinabalu, Sabah, West Malaysia(estimated: N6.0292, E116.5473,  1854 ma.s.l.).  Adultmale ( MCZR43591) collected by John A. Griswold Jr.in 1937 from Kadmayan R, near Kiau, Sabah, West Malaysia(estimated: N6.029788, E 116.489732,  971 ma.s.l.).  Diagnosis.Morphological analyses of the four specimens from the highlands of Sabahconfirms the placement of this population in the genus  Asthenodipsasbased 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 thtouching the eye; 4–6 infralabials, 2 ndor 3 rdpair 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, 5& 6; Fig. 2& 3).  Description of holotype.Adult female SVL 557 mmand 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 rdpair 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).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 thventral. The dark patch starts as a narrow stripe on the 4 th& 5 thdorsal 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.   TABLE 2.Summary statistics for  Asthenodipsas stuebingi  sp. nov.and the different populations of  A. laevis, SD = standard deviation and N = sample size.       A. stuebingi sp. nov.   A. laevis   A. laevis   A. laevis  A. laevis   Borneo  Thai-Malay  Java  Sumatra   Peninsula   Posterior dorsal scale rows  mean (±SD) 15.00 (±0.00) 13.00 (±0.00) 13.00 (±0.00) 13.00 (±0.00) 13.00 (±0.00)  range 15 13 13 13 13  N 4 43 9 11 5   Ventrals  mean (±SD) 168.75 (±4.79) 158.16 (±4.46) 157.44 (±7.09) 157.64 162.20  range 165–175 150–167 148–173 (±6.17) 150–165 (±2.59) 158–165  N 4 43 9 11 5   Subcaudals  mean (±SD) 39.50 (±5.45) 41.53 (±3.95) 42.89 (±5.11) 39.91 (±3.33) 43.8 (±4.97)  range 35–47 34–49 37–51 35–44 37–50  N 4 43 9 11 5   Supralabials  mean (±SD) 6.0 (±0.0) 6.02 (±0.15) 6.00 (±0.00) 6.09 (±0.30) 6.00 (±0.00)  range 6.0 6–7 6.00 6–7 6.00  N 4 43 9 11 5   Infralabials  mean (±SD) 5.00 (±1.15) 5.93 (±0.40) 5.44 (±0.53) 5.00 (±0.45) 5.2 (±0.45)  range 4–6 5–7 5–6 4–6 5–6  N 4 43 9 11 5   Infralabial pair in contact  mean (±SD) 2.5 (±0.58) 2.95 (±0.21) 3.00 (±0.00) 2.82 (±0.40) 3.00 (±0.00)  range 2–3 2–3 3.00 2–3 3.00  N 4 43 9 11 5   TABLE 3. Pairwise matrix of statistically significant mean differences of characters among species of the Asthenodipsas   laevisgroup. Abbreviations are in the Materials and methods.  A. jamilinaisi A. stuebingi A. laevis A. laevisThai-Ma-  A. laevis A. laevis  sp. nov. sp. nov.Borneo lay Peninsula Java Sumatra Variation ( Table 4; Fig 2& 3).The paratypesclosely resemble the holotypein overall external morphology, colouration, and pattern. All paratypeshave a slightly darker ground colour than the holotypeand 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 ZMB65429 and MCZR43591 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.      A. jamilinaisi  sp. nov. - - - - - -    A. stuebingi  sp. nov. SubC - - - - -    A. laevisBorneo PDSR, Ven, PDSR, Ven, InfL, - - - -    A. laevisThai-Malay SubC PDSR, Ven, InfL-contact PDSR, Ven, InfL- - - - -  Peninsula SubC contact    A. laevisJava PDSR, Ven, PDSR, Ven InfL - - -  SubC    A. laevisSumatra PDSR PDSR InfL - - -  Comparison.  Asthenodipsas stuebingi  sp. nov.can be differentiated from  Aplopeltura boaby 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  Pareasby their possession of preocular and subocular scales (absent vs. present), supralabials in contact with orbit (3 rd& 4 thcontact orbit vs. no supralabials in contact with orbit) and anterior single inframaxillary (present vs. absent) ( Grossmann & Tillack 2003).  Asthenodipsas lasgalenensis,  A. tropidonotusand  A. vertebraliscan be differentiated from the new species by their higher number subcaudals (54–77 vs. 35–47), pairs of infralabials in contact (1 stvs. 3 rd) and more pairs of posterior inframaxillaries (three vs. two). In addition,  A. vertebralisand  A. tropidonotuscan be differentiated from  A. stuebingi  sp. nov.by their higher number of ventrals (195–215 vs. 165–175). Adult  A. lasgalensiscan 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. malaccanato 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. laevisto which it was previously confused,  A. stuebingi  sp. nov.can be differentiated by its larger adult length, (Max SVL 557mmvs. 373mm), dorsal scales rows (15/15/15 vs. 15/15/13) and sharp vertebral keel (present vs. absent) ( Figs. 3F& 4F) ( Tables 2–6).  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). A key to the family Pareidaeof Borneo is presented below.  Distribution ( Fig. 8).  Asthenodipsas stuebingi  sp. nov.is only known from the highlands of Sabah, East Malaysiaat Mount Kinabalu, Kundasang and the Crocker Range. It is likely to range further throughout the island and found in similar upland habitats in Sarawak, Malaysiaand Kalimantan, Indonesian Borneo.  Etymology.The specific epithet  stuebingiis 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 Sabahfrom 900–2000 ma.s.l.. This is in contrast to its congener  A. laevisthat is widely distributed in Borneo and recorded from many lowland localities up to 1150 min 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). 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 1mabove the ground. The paratype ZMB65429 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) — 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. 2430030363 [151,563,821,847] Mountain Smooth Slug Snake 3 504 1 Sabah 2430030365 2009-03-25 Adult & Paul Yambun Imbun & Fred Tuh Yit Yu & Safrie Malaysia East 1859 5.82324 Minduk Sirung 1 116.34724 Crocker Range Park 3 504 1 Sabah holotype 2430030360 2014-10-26 Adult & Siti Azizah Kusop & Junaidi Ais & Adzmie 1341 5.988087 Kampung Desa Aman 1 116.57016 Kundasang 3 504 1 paratype 2430030364 1994-08 ZMB Adult & Rudolf Malkmus & Andreas N Malaysia West 1854 6.0292 Kamborangoh Road 7 116.5473 Mount Kinabalu 3 504 1 Sabah paratype 2430030357 MCZ Adult & John A. Griswold Jr. & Kadmayan R Malaysia 971 6.029788 Kiau 1 116.48973 West 3 504 1 Sabah paratype