Pareas carinatus WAGLER, 1830
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Pareas carinatus
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| Higher Taxa | Pareidae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | Pareas carinatus carinatus (WAGLER 1830) Pareas carinatus tenasserimicus POYARKOV et al. 2022 |
| Common Names | E: Keeled Slug Snake G: Gekielte Schneckennatter Chinese: 棱鳞钝头蛇 |
| Synonym | Amblycephalus carinatus H. BOIE in SCHLEGEL 1826: 238 (nomen nudum) Amblycephalus carinatus BOIE in SCHLEGEL 1826: 293 (nomen nudum) Amblycephalus carinatus BOIE in SCHLEGEL 1828: 251 (nomen nudum) Pareas carinata — WAGLER 1830: 181 Dipsas carinata — SCHLEGEL 1837: 285 Pareas carinata — DUMÉRIL, BIBRON & DUMÉRIL 1854: 439 Leptognathus carinatus — JAN 1863 Amblycephalus carinatus — DE ROOIJ 1917: 277 Pareas carinatus — COCHRAN 1930 Amblycephalus carinatus carinatus — MERTENS 1930 Amblycephalus carinatus — SMEDLEY 1931: 53 Amblycephalus carinatus — KOPSTEIN 1936 Pareas carinatus — SMITH 1943 Pareas carinatus carinatus — HAAS 1950 Amblycephalus carinatus — DEUVE 1961: 30 Pareas carinatus — MANTHEY & GROSSMANN 1997: 376 Pareas carinatus — COX et al. 1998: 78 Pareas carinatus carinatus — CHAN-ARD et al. 1999: 177 Pareas carinatus — SCHMIDT & KUNZ 2005: 41 Pareas carinatus carinatus — NGUYEN et al. 2009 Pareas carinatus — WALLACH et al. 2014: 535 Pareas (Pareas) carinatus — POYARKOV et al. 2022 |
| Distribution | Indonesia (Java, Lombok, Sumatra, Bali [M. Auliya, pers. comm.]), Malaysia (Malaya and East Malaysia) Burma (Myanmar), Thailand, Vietnam, Laos , Cambodia, China (Yunnan) tenasserimicus: Thailand; Type locality: Suan Phueng District, Ratchaburi Province, Thailand. unicolor: Cambodia Type locality: Java |
| Reproduction | oviparous |
| Types | Lectotype: RMNH 954C, adult male, designated by Poyarkov et al. 2022; Syntypes: RMNH 954 (pers. comm. Gernot Vogel), ZSI 8021, ZSI 8022 (Bhosale et al. 2021) Holotype: MNHN-RA 1938.0149 [unicolor] |
| Diagnosis | Diagnosis (genus): The genus Pareas is morphologically characterized by having medially smooth or keeled dorsal scales in 15 rows throughout the body; the ventrals preceded by a strongly enlarged preventral, larger than the ventrals; the subcaudals divided; the absence of mental groove; suboculars are usually present; supralabials usually not touching the eye (except in P. monticola and P. stanleyi); the anterior single inframaxillary shield lacking, three pairs of inframaxillaries, the first pair distinctly elongated, posterior inframaxillaries usually as long as wide or wider than long (Grossmann & Tillack 2003). Updated diagnosis (genus): Dorsal scales smooth or keeled, in 15 rows throughout the body; vertebrals slightly larger than other dorsal scales or not enlarged; one (rarely two) loreals; preocular and subocular scales present; supralabials generally not contacting the eye (except for P. monticola and P. stanleyi); three anterior temporals; the anterior single inframaxillary shield absent (Figs. 5H–5G); three pairs of inframaxillaries, all in contact with each other; subcaudals divided (Wagler, 1830; Smith, 1943; Taylor, 1965; Vogel et al., 2020; our data; see Table S14 for details; from Poyarkov et al. 2022). Diagnosis: Pareas carinatus differs from all other members of the genus Pareas by the following combination of morphological characters: body slender, maximal total length of 702 mm; frontal scale hexagonal with lateral sides parallel to the body axis; anterior pair of chin shields longer than broad; loreal and prefrontal not contacting the eye; 1–3 suboculars; usually one postocular; temporals 3 + 4 or 3 + 3; three median vertebral rows slightly enlarged; 7–9 infralabials; 15 dorsal scale rows, at midbody the five upper rows might be slightly keeled; 158–194 ventrals; 54–96 subcaudals, all divided; dorsum yellow-brown with dark vertebral blotches and dark mottling, transverse dark bands on the body present or absent; upper postorbital stripes continue to nape forming one or two longitudinal black spots; iris bronze laterally, beige dorsally (Wagler, 1830; Poyarkov et al. 2022). Body scalation. Dorsal scales in 15–15–15 rows, slightly keeled at midbody, and without apical pits; three vertebral scale rows slightly enlarged; outermost dorsal scale row not enlarged; ventrals 170 (+ 1 preventral), without lateral keels; subcaudals 67; cloacal plate single (Poyarkov et al. 2022). Head scalation. Rostral not visible from above; one nasal; two internasals, much wider than long, narrowing and slightly curving back laterally (in dorsal view), anteriorly in contact with rostral, laterally in contact with nasal and loreal, posteriorly in contact with prefrontal, not contacting preocular; two large irregular pentagonal prefrontals, much larger than internasals and with a slightly diagonal suture between them, not contacting the eye; frontal scale hexagonal with the lateral sides parallel to the body axis, longer than wide, smaller than parietals; one preocular; two suboculars; one postocular, not fused with subocular; one loreal in contact with prefrontal, not touching the eye; 7/7 supralabials, 3rd and 5th SL touching the subocular, none of them reaching the eye, 7th by far the largest, elongated; temporals 3 + 4; 9/9 infralabials, the anterior most in contact with the opposite along the midline, bordering mental, anterior 5 pairs of infralabials bordering anterior chin shields; 3 pairs of chin shields interlaced, no mental groove under chin and throat; anterior chin shields relatively large, generally wider than long, followed by two pairs of chin shields much wider than long (Poyarkov et al. 2022). Coloration. After over 200 years in preservative, the dorsal and ventral surfaces of the head, brownish with some dark-brown dusted spots (Fig. 7). Head with two lateral dark-brown postorbital stripes: the lower one is an interrupted dark line starting from the posterior edge of the eye, going diagonally down onto the anterior part of the last supralabial; the upper postorbital stripe is a dark-brown line running from the postocular backwards to the dorsal scales on the neck, where it meets the similar line on the opposite side of the body forming a narrow X-shaped dark-brown marking on the nuchal area (Fig. 7A). Upper labials marked with some fine irregular brown speckling (Figs. 7C and 7D). Dorsal surface is nearly uniformly light brown with slightly visible dark cross bands; ventral surfaces yellowish with sparse brownish mottling forming the interrupted line along the midline, descending backwards. Coloration in life unknown (Poyarkov et al. 2022). Comparisons: Pareas carinatus differs from P. berdmorei (revalidated below) by the generally smaller body size (494.3 ± 73.3 mm vs. 554.9 ± 73.3 mm); by slightly lower number keeled dorsal scale rows (6.5 ± 2.9 vs. 8.9 ± 2.8); and by generally thicker upper postorbital stripe and more pronounced dark markings on the nape (vs. thinner postorbital stripe and less pronounced dark markings on the nape); P. carinatus differs from P. nuchalis by prefrontal not contacting the eye (vs. in contact); by the absence of the large ring-shaped black blotch on the nape (vs. present); by lower number of ventrals (171.35 ± 9.3 vs. 209.89 ± 5.3); lower number of subcaudals (73.3 ± 7.6 vs. 111.1 ± 6.1); and by having keeled dorsal scales (vs. dorsal scales totally smooth). Morphological comparisons between all species of the subgenus Pareas are detailed in Table 2. Pareas carinatus can be distinguished from other species of Pareas belonging to subgenus Eberhardtia stat. nov. by having two or three distinct narrow suboculars (vs. one thin and elongated) and by having a hexagonal frontal with its lateral sides parallel to the body axis (vs. subhexagonal) (see Tables S13 and S14) (Poyarkov et al. 2022).\ Diagnosis (tenasserimicus): Pareas carinatus tenasserimicus ssp. nov. differs from the nominative subspecies by the following combination of morphological characteristics: total length 702 mm; anterior pair of chin shields as long as broad; two postoculars; temporals 3 + 3; 15 dorsal scale rows slightly keeled in 7 scale rows at midbody; 194 ventrals; 96 subcaudals; dorsum light brown to beige, 73 weak dark vertebral spots; transverse dark bands on the body absent (Figs. 9D and 9E); upper postorbital stripes not contacting each other on the nuchal area forming a weak X-shaped dark marking with curved branches; ventral scales beige with dense brownish mottling not forming the interrupted midventral line (Poyarkov et al. 2022). For more details see Poyarkov et al. 2022. |
| Comment | Behavior: nocturnal. Subspecies: Pareas carinatus unicolor (BOURRET 1934) has been moved to P. berdmorei by Poyarkov et al. 2022. Type species: Dipsas carinata REINHARDT is the type species of the genus Pareas WAGLER 1830: 181. Type genus: Pareas WAGLER 1830 is the type genus of the family Pareidae ROMER 1956 (not Pareatidae as sometimes used, see Savage 2015 for an explanation) and the subfamily Pareinae ROMER 1956. Group: The carinatus complex of Pareas includes P. carinatus, nuchalis, temporalis, and menglaensis (Le et al. 2021). Le et al. 2021: 449 have a key to the members of the carinatus complex. See also Poyarkov et al. 2022. Habitat: Snakes of the genus Pareas are mainly arboreal. This species is semi-arboreal (Harrington et al. 2018). Diet: slugs and snails; pareid snakes have more teeth on the right mandible than on the left for functional specialization in feeding on the dextral majority of land snails (Hoso 2017). Synonymy: Kaiser et al. 2013 rejected the (sub-) generic names Dannyleeus Hoser 2012, Katrinahoserserpenea Hoser 2012 invalid and rejected their use instead of Pareas. Distribution: Reported sometimes from, but not listed for Borneo by Stuebing et al. 2014. For a map of the P. hamptoni species complex see Ding et al. 2020: 180 (Fig. 1). Key: Vogel et al. 2021 provide a key to the Pareas slug snakes of Myanmar. Quah et al. 2021 provide a key to the species of Pareidae of Borneo. Poyarkov et al. 2022: 28 present a key to the genera and subgenera of Pareinae. |
| Etymology | The species name “carinatus” is a Latin adjective in nominative singular, masculine gender, derived from “carina” for a “keel of a ship”, and is given in reference to the keeled dorsal scales in this species (Poyarkov et al. 2022). The genus name is a latinized noun in masculine gender derived from the Greek noun “pareias” (πaρείaς), a name of a mythological snake dedicated to Asclepius, and which was believed to be non-venomous and create a furrow anytime it moves (Poyarkov et al. 2022). |
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