Stegonotus derooijae, Ruane & Richards & McVay & Tjaturadi & Krey & Austin, 2017

Ruane, Sara, Richards, Stephen J., McVay, John D., Tjaturadi, Burhan, Krey, Keliopas & Austin, Christopher C., 2017, Cryptic and non-cryptic diversity in New Guinea ground snakes of the genus Stegonotus Duméril, Bibron and Duméril, 1854: a description of four new species (Squamata: Colubridae), Journal of Natural History (J. Nat. Hist.) 52 (13 - 16), pp. 917-944 : 929-933

publication ID	https://doi.org/ 10.1080/00222933.2017.1391959
publication LSID	lsid:zoobank.org:pub:9E21390E-3FD4-40EB-9442-31BC92A76B4F
persistent identifier	https://treatment.plazi.org/id/400B69E0-73E1-4D0B-8DCD-32CA7BEA6D3F
taxon LSID	lsid:zoobank.org:act:400B69E0-73E1-4D0B-8DCD-32CA7BEA6D3F
treatment provided by	Felipe
scientific name	Stegonotus derooijae
status	sp. nov.

Treatment

Stegonotus derooijae sp. nov.

( Figures 2−4 View Figure 2 View Figure 3 View Figure 4 , 6 View Figure 6 , Table 1, Appendix 1)

Stegonotus diehli Lindholm 1905

Holotype

MZB. Ophi. 3288 (field number SJR 7788 , tissue ABTC 90225 View Materials ), adult male. Collected by S. Richards, B. Tjaturadi and K. Krey on 26 June 2005, from Waibya Camp , Salawati Island, Raja Ampat Regency, West Papua, Indonesia, elevation 75 m asl (0.956383°S, 130.784333°E) ( Figure 4 View Figure 4 ). GoogleMaps

Paratypes

MZB.Ophi. 3293 (field number SJR 7789 , tissue ABTC 90226 View Materials ; Figure 6 View Figure 6 ), same data as holotype; SAMA R 70467 (field number SJR 7586 , tissue ABTC 90123 View Materials ) collected by S GoogleMaps . Richards, B GoogleMaps . Tjaturadi and K . Krey on 9 June 2005 from Warinkabom , Batanta Island, Raja Ampat Regency, West Papua Province, Indonesia, elevation 50 m asl (0.836942°S, 130.72162°E) GoogleMaps .

Referred specimens

MZB.Ophi. 3292 (field number SJR 7650 , morphology only) collected by S . Richards, B . Tjaturadi and K . Krey on 13 June 2005 from Urbinasopen , Waigeo Island, Raja Ampat Regency, West Papua Province, Indonesia, elevation 45 m asl (0.337183°S, 131.258800°E) GoogleMaps .

Diagnosis

A new species of Stegonotus that can be diagnosed from its congeners by the following combination of characters: a dark grey or brown unpatterned dorsum with a white or cream venter with dorsal scale pigmentation continuing onto some or many of the ventral scales, dark grey pigmentation on the subcaudal scales extending from the dorsal scale pigmentation and with grey on the anterior edges of some subcaudal scales, 17 dorsal scale rows at midbody, 178−197 ventral scales and 90−94 divided subcaudal scales, two preocular scales, seven (rarely nine) supralabial scales, eight or nine infralabial scales, with the supralabial and infralabial scales cream and with grey pigmentation.

Description of holotype

Adult male in excellent state of preservation, with a short (<5 cm) ventral slit midbody. Body shape relatively gracile with a narrow head. Snout–vent length 455 mm with 181 ventral scales, tail length 193 mm with 94 divided subcaudal scales. Anal scale single. Head length 17.0 mm, as measured from the snout to the rear of the quadrate, width 8.7 mm as measured across the widest point of the head anterior to the quadrate. Eyes 2.6 mm horizontal diameter, pupil shape is subcircular. Supralabials seven with the third and fourth in contact with the eye. Infralabials eight, with first pair in contact behind mental, infralabials one to five in contact with inframaxillaries. Rostral broader than high, 3.2 mm wide/ 2.2 mm high, visible from above. Nasal in contact with first supralabial. Single loreal, in contact with nasal, preoculars, prefrontal, and supralabials one, two and three. Circumoculars five: one supraocular, two preoculars, zero suboculars and two postoculars. Anterior temporals two. Dorsal surface of head includes pair of internasals (width 2.1 mm /length of suture 1.6 mm), pair of prefrontals (width 3.4 mm /length of suture 2.8 mm), pair of supraoculars (width 2.0 mm/length 2.7 mm), frontal longer than wide (length 4.6 mm /anterior width 4.0 mm), pair of parietals (length of suture 5.1 mm). Two pairs of inframaxillaries, (anterior inframaxillary suture length 2.6 mm, posterior inframaxillary suture length 1.5 mm), posterior inframaxillaries in contact with each other. Dorsal scale rows 17−17−15 (15th ventral from anterior, midbody and 15th ventral anterior to cloaca). A distinct pair of apical pits on most scales on the dorsum.

Coloration in life

Overall coloration in life similar to that described for preserved specimen except the white mottling on dorsal scales near the venter and lateral head scales has distinctly yellow pigment in life ( Figure 4 View Figure 4 ).

Coloration in preservative

Overall dorsal coloration dark grey-brown with no pattern down the dorsal side of the body and tail but some dorsal scales nearest the venter whitish-cream. Colour of iris opaque grey. Dorsum of head, including rostral, internasals, prefrontals, frontal, supraoculars and parietals brownish-grey and showing iridescence, with extensive white mottling on dorsal and lateral head scales including temporal scales. Supralabials with grey pigmentation that is darker on the dorsal edge and becoming almost entirely cream approaching the ventral edge of the scales. Infralabials cream with limited mottled grey pigment on the edges of each scale. Ventral scales cream with limited grey pigmentation from the dorsal scales extending on to some ventral scales in small patches but not crossing the ventral scales. Anal plate cream, subcaudals all with grey pigmentation concentrated on the anterior edge of each scale and becoming greyer moving posteriorly. Ventral scales show iridescence under lights.

Variation

The holotype is the only sexually mature individual in the type series. At just 290 mm snout–vent length, SAMA R 70467 is clearly a juvenile, whereas MZB .Ophi.3293 is possibly a juvenile female because it lacks any sign of gonadal development under dissection despite being around the same size as the sexually mature male holotype. Apical pits are absent in the two paratypes ( MZB.Ophi.3293, SAMA R 70467) and referred specimen ( MZB.Ophi.3292) . In overall colour pattern, scalation and body shape paratypes are similar to the holotype excepting: MZB .Ophi. 3293 and SAMA R 70467 lack the extensive white mottling on the dorsal and lateral head scales; MZB .Ophi. 3293 with 178 ventrals, 81 subcaudals (tail incomplete), nine rather than eight infralabials; SAMA R 70467 with 178 ventrals, 90 subcaudals .

Etymology

The species epithet is a noun in the genitive case and is a patronym in honour of Dr Nelly De Rooij, who described many taxa from New Guinea and Indonesia, including Stegonotus florensis .

Natural history and distribution

Currently known only from the Raja Ampat islands of Batanta, Salawati and Waigeo in eastern Indonesia. This small, slender species was active on the forest floor in moderately to heavily disturbed lowland (<100 m above sea level) rainforest at night. At each site it occurred in sympatry with S. iridis sp. nov., described above.

Comparisons

Stegonotus derooijae sp. nov. is part of the S. diehli complex ( Figure 3 View Figure 3 ) and this taxon would have been formerly considered S. diehli . It differs morphologically from S. diehli by having 17 dorsal scale rows at midbody versus 15 dorsal scale rows in S. diehli . Stegonotus derooijae sp. nov. also differs from S. diehli in having higher numbers of ventral scales (178−197 in S. derooijae sp. nov. versus 162−174 in S. diehli ) and subcaudal scales (90−94 in S. derooijae versus 73−85 in S. diehli ) for the specimens we examined (excluding specimens with incomplete tails; Appendix 1). It differs from the new species (described below) from Southern Highlands and Chimbu Provinces by having two rather than (usually) one preocular scale. The overall dark coloration of S. derooijae sp. nov. distinguishes it from the sympatric S. iridis sp. nov. described above.