Lygosoma samajaya Karin & Freitas & Shonleben & Grismer & Bauer & Das 2018, sp. nov.
Creators: name: Karin, Benjamin R.
name: Freitas, Elyse S.
name: Shonleben, Samuel
name: Grismer, L. Lee
name: Bauer, Aaron M.
name: Das, Indraneil
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Scincidae
Lygosoma
Lygosoma samajaya

description: Lygosoma samajaya sp. nov.
Figs. 1–6
Holotype. An adult of unknown sex (CAS 259777; field number SS 0137) collected on 24 June 2014 by Indraneil Das, Benjamin Karin, and Samuel Shonleben from a pitfall trap placed in Sama Jaya Forest Reserve, Kuching, Sarawak, Malaysia (1.523683ºN, 110.38793ºE; WGS84; elevation 25 m; Figs. 2–4). The specimen was spotted at the edge of the pitfall trap, and directed into the bucket by hand.
Paratype. An adult of unknown sex (UNIMAS 9503; field number SS 0031) collected on 2 February 2013 by Samuel Shonleben and Indraneil Das from a pitfall trap at the foothills of Gunung Gumbang, Kuching Division, Sarawak, Malaysia (1.267ºN, 110.050ºE; WGS84; elevation 167 m; Figs. 2, 4). No tissue sample was collected.
Diagnosis. Lygosoma samajaya sp. nov. is distinguished from all other south-east Asian congeners by the following combination of characters: (1) quinquecarinate dorsal and lateral scales; (2) 13 or 14 subdigital lamellae on the fourth toe; (3) 10 or 11 subdigital lamellae on the fourth finger; (4) paravertebral scale rows 61; (5) midbody scale rows 28–30; (6) lacking enlarged nuchals; (7) supranasals in medial contact; (8) paired frontoparietals; (8) seven supralabials; (9) six infralabials; (10) adult SVL 70 mm; and (11) tail shorter than SVL.
Description of Holotype. Medium sized, SVL 70.1 mm; head weakly differentiated from neck; head width 9.0 mm, 6.8 mm at center of eyes; neck width 8.7 mm; head height 4.8 mm; head length 11.0 mm; nostril–snout length 1.6 mm; nostril–eye length 3.1 mm; internarial distance 2.8 mm; interocular distance 5.1 mm; ear opening small, 0.7 mm in length and 0.6 mm in height. Body slightly dorsoventrally depressed, 9.6 mm in width and 6.7 mm in height at widest point, about midway between the limbs; axilla–groin length 39.8 mm; snout–forelimb length 22.7 mm (axilla–groin length 1.75x snout–forelimb length); forelimb 13.2 mm; hindlimb 18.2 mm; fourth fingers (left/ right) 3.4/ 3.3 mm in length; fourth toes (left/right) 6.9/ 6.2 mm in length; tail narrower than body, incomplete, 18.2 mm in length from vent; tail width 6.7 mm at its base.
Scales glossy; ventral scales smooth; dorsal scales with five keels (Fig. 5); keels indistinct and nearly smooth near the neck and becoming more prominent posteriorly; scales on limbs much smaller than body scales, moderately keeled; 30 midbody scale rows; 60 paravertebral scale rows; 58 ventral scale rows; four slightly enlarged precloacal scales; 36 rows of scales between the forelimb and hindlimb insertions; limbs well-developed, pentadactyl; keeled scales on dorsal surface of limbs; adpressed hindlimb does not reach halfway to base of adpressed forelimb; lamellae under fingers (left/right) I:3/3, II:9/9, III:10/10, IV:11/11, V:5/5; lamellae under toes (left/right) I:4/4, II:9/8, III:12/12, IV:13/13, V:10/10 (Fig. 5).
Rostral separated from frontonasal by supranasals, nearly trapezoidal with slight projection along midline towards frontonasal; supranasals in contact along the midline; nasal contacts supranasal, rostral, first supralabial, and the anterior loreal; supranasal enters the nostril opening; two loreals, posterior loreal almost twice the length of the slightly taller anterior loreal; frontonasal in broad contact with the frontal; prefrontals widely separated; four supraoculars, first two in contact with frontal, second to fourth in contact with frontoparietal; frontoparietals in broad contact; interparietal with pineal eyespot near the posterior margin; parietals in broad contact behind the interparietal; no enlarged nuchals; seven supraciliaries; three preoculars, uppermost largest; lower eyelid scaly, without window; seven supralabials, fifth below the eye; six infralabials; mental much wider than long; postmental slightly larger than mental; two pairs of enlarged chin shields; first pair of chin shields in medial contact; second pair of chin shields separated by two small gular scales, slightly larger than first pair. A small tick is preserved between the fourth and fifth gular scale rows (see Fig. 6 for dorsal and lateral diagram of head scales).
Colour in Alcohol. Dorsal surface of head, body, limbs, and tail uniform brown; ventral surface of head, body and limbs uniform cream-coloured; a dark brown lateral stripe extends from nostril through the eye and fades to the brown dorsum colour halfway between the limbs, bordered above by a thin whitish line that begins above the eye and terminates above the forelimb insertion; ventral surface of tail begins to darken posteriorly (though incomplete).
Variation. The paratype matches the holotype in size and form, but differs in having 28 (vs. 30) scale rows around the midbody; 61 (vs. 60) paravertebral scale rows; 60 (vs. 58) ventral scale rows; 58 subcaudals (tail of holotype incomplete); (left/right) 10/11 (vs. 11/11) lamellae under the fourth finger (see Table 1 for comparison and other measurements of paratype). Though we do not have molecular data for the paratype, we regard it as a member of this species due to the high degree of morphological similarity observed.
Distribution. Only known from two localities in western Sarawak that are approximately 50 km apart (Fig. 2). It is presumed to occur more widely in lowland rainforest with dense leaf-litter at other sites in western Borneo. No genetic data is available for the paratype, so we cannot assess molecular divergence or connectivity between the two localities and we are assuming that based on morphology, they are conspecific and not cryptic species.
Natural History. Both specimens were collected in pitfall traps placed among leaf litter in dense, closedcanopy forest. In Sama Jaya, the area is primarily heath forest (Kerangas), while in Gumbang it is disturbed, partially logged, mixed dipterocarp forest. We presume the new species is semi-fossorial as its elongate body morphology suggests (Grismer 2011).
Etymology. The species epithet samajaya is a proper noun in apposition that refers to the locality of collection of the holotype at the Sama Jaya Forest Reserve in Kuching, Sarawak, Malaysia. This name draws attention to the importance of small urban rainforest parks in sustaining species diversity (see Discussion).
Comparisons. Here, we focus comparisons on the 17 congeners that occur in south-east Asia. As our phylogenetic analysis places the new species outside of the Indian radiation of Lygosoma (Fig. S1), we exclude Indian congeners from the analysis. Lygosoma samajaya sp. nov. differs from nearly all other Lygosoma in having five distinct keels on the dorsal scales, an uncommon feature in Lygosoma. Of the south-east Asian congeners, most have smooth dorsal scales— L. angeli (Smith, 1937), L. anguinum (Theobald, 1868), L. bampfyldei, L. corpulentum Smith, 1921, L. frontoparietale (Taylor, 1962), L. haroldyoungi (Taylor, 1962), L. isodactylum (Günther, 1864), L. koratense Smith, 1916, L. lineolatum, L. popae (Shreve, 1940), L. quadrupes (Linnaeus, 1766), L. tabonorum Heitz, Diesmos, Freitas, Ellsworth & Grismer, 2016; juveniles and subadults of one species possess pseudokeels (i.e., the optical illusion of keels underlying a smooth scale; sensu Ziegler et al. (2007))— L. boehmei Ziegler, Schmitz, Heidrich, Vu & Nguyen, 2007; two species usually possess smooth scales but occasionally show weak keels— L. bowringii and L. veunsaiensis Geissler, Hartmann, & Neang, 2012; and one species possesses tricarinate scales— L. opisthorhodum Werner, 1910. Only one other species of south-east Asian Lygosoma also possesses quinquecarinate scales, Lygosoma herberti from southern Thailand and Peninsular Malaysia, to which Lygosoma samajaya sp. nov. is most closely related. The new species is distinguished from L. herberti in possessing fewer lamellae under the fourth toe (13–14 vs. 15) and fourth finger (10–11 vs. 12), more paravertebral scale rows (61 vs. 54–58), and being slightly larger in adult body size (SVL 69–71 mm vs. 56–66 mm).
We further differentiate the new species from the south-east Asian congeners that possess some degree of dorsal scale keeling. Lygosoma samajaya sp. nov. is distinguished from L. boehmei by smaller body size (SVL 69– 71 mm vs. 91 mm), in possessing a tail shorter than SVL (vs. longer), six infralabials (vs. seven) possessing true keels (vs. pseudokeels); from L. bowringii in lacking enlarged nuchal scales (though some L. bowringii may also lack nuchals) and in coloration (sides same color as dorsal surface, fading to white vs. sides with red and yellow, fading to white) and in pigmentation patterns (sides solid vs. a lateral stripe and spotting); and from L. veunsaiensis by possessing supranasals in contact (vs. separated), seven supralabials (vs. five), six infralabials (vs. five), external ear openings present (vs. absent), 28–30 midbody scale rows (vs. 22), more lamellae under the fourth toe (13–14 vs. 9) and fourth finger (10–11 vs. 5).
The new species is easily distinguished from the two congeners known to occur on Borneo, L. bowringii and L. bampfyldei: from L. bowringii as above; and from L. bampfyldei in being much smaller in body size (SVL 69–71 vs. 110–142 mm), in possessing keeled (vs. unkeeled) dorsal scales, and in having fewer midbody scale rows (28– 30 vs. 38).
Four other species of Lygosoma (L. albopunctata, L. opisthorhodum, L. quadrupes, and L. tabonorum) occur in close enough proximity to Borneo (Sunda Shelf or the Philippines) to warrant further comparison beyond differences in carination. Lygosoma samajaya sp. nov. is further differentiated by the following characters: from L. albopunctata by showing a greater midbody scale row count (28–30 vs. 14) and larger body size (SVL 69–71 mm vs. 35–47 mm); from L. opisthorhodum by possessing quinquecarinate (vs. tricarinate) dorsal scales, in being larger in size (SVL 69–71 mm vs. SVL 45 mm), with tail shorter (vs. longer) than SVL, and in color pattern (uniform brown with dark anterolateral stripe vs. black-brown, brighter toward posterior, with a bright lateral stripe, starting at subocular region and extending below tympanic region to the midbody); and from L. quadrupes and L. tabonorum by possessing separated frontoparietals (vs. fused), absence (vs. presence) of enlarged nuchals, and a greater fourth toe lamellae count (13–14 vs. 6–7 in each).
description: Published as part of Karin, Benjamin R., Freitas, Elyse S., Shonleben, Samuel, Grismer, L. Lee, Bauer, Aaron M. & Das, Indraneil, 2018, Unrealized diversity in an urban rainforest: A new species of Lygosoma (Squamata: Scincidae) from western Sarawak, Malaysia (Borneo), pp. 345-362 in Zootaxa 4370 (4) on pages 348-353, DOI: 10.11646/zootaxa.4370.4.2, http://zenodo.org/record/1146423