Stegonotus admiraltiensis, 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 : 937-939

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/03DA87E1-D400-4575-04CA-E5D087BD9844
treatment provided by	Felipe
scientific name	Stegonotus admiraltiensis
status	sp. nov.

Treatment

Stegonotus admiraltiensis sp. nov.

( Figures 2−4 View Figure 2 View Figure 3 View Figure 4 , 8 View Figure 8 , Table 1)

Stegonotus modestus ( Schlegel 1837)

Holotype

LSUMZ 93598 View Materials (field number CCA 2087 View Materials ), adult male. Collected by Christopher C. Austin on 1 September 2001 from Penchal Village on Rambutyo Island , Manus Province, Papua New Guinea, elevation 58 m asl, (2.3283333°S, 147.7666667°E). GoogleMaps

Paratypes

LSUMZ 93599 View Materials (field number CCA 2092 View Materials ) and LSUMZ 93600 View Materials (field number CCA 2097 View Materials ), both collected by Christopher C . Austin on 3 September 2001 from northeast of Penchal Village on Rambutyo Island, Manus Province, Papua New Guinea, elevation 100 m asl (2.3405000°S, 147.7945000°E); LSUMZ 93597 View Materials (field number CCA 2042 View Materials ), collected by C GoogleMaps . Austin on 29 August 2001 from near Peyon Village on Los Negros Island, Manus Province, Papua New Guinea, elevation 10 m asl (2.0326667°S, 147.4341667°E) GoogleMaps .

Diagnosis

Stegonotus admiraltiensis can be diagnosed from its congeners by the following combination of characters: a reddish-tan unpatterned dorsum with an immaculate white or cream venter that may be barely darker approaching and continuing posteriorly onto the subcaudal scales, 17 or 19 dorsal scale rows at midbody, the presence of two apical pits on most or all dorsal scales, 202−214 ventral scales and 93−98 divided subcaudal scales, two preocular scales, eight supralabial scales, nine or ten infralabial scales, with the supralabial and infralabial scales cream with little or no dark pigmentation.

Description of holotype

Adult male in excellent state of preservation, tail complete, short (~ 10 cm) ventral slit midbody for DNA tissue sample, hemipenes partially everted. Snout–vent length 658 mm with 208 ventral scales, tail length 185 mm with 98 divided subcaudal scales. Anal scale single. Head length 27 mm, as measured from the snout to the rear of the quadrate, width 15 mm, as measured across the widest point of the head anterior to the quadrate. Eyes 2.9 mm horizontal diameter, pupil shape subcircular. Supralabials eight with the fourth and fifth in contact with the eye. Infralabials 10 with first pair in contact behind mental, infralabials one to six in contact with inframaxillaries. Rostral broader than high, 5 mm wide/ 2.5 mm high, visible from above. Nasal in contact with first supralabial. Single loreal, in contact with nasal, preoculars, prefrontal and supralabials 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 2.9 mm /length of suture 1.5 mm), pair of prefrontals (width 4.0 mm/length of suture 4.0 mm), pair of supraoculars (width 2.5 mm /length 4.8 mm), frontal longer than wide (length 5.9 mm / anterior width 5.4 mm), pair of parietals (length of suture 6.5 mm). Two pairs of inframaxillaries, (anterior inframaxillary suture length 2.8 mm, posterior inframaxillary suture length 1.7 mm), posterior inframaxillaries in contact with each other. Dorsal scale rows 17−19−15 at 15th ventral from anterior, midbody, and 15th ventral anterior to cloaca.

Variation

Paratypes similar to the holotype excepting the following: LSUMZ 93597 and LSUMZ 93599 with 17 rather than 19 dorsal scale rows midbody; LSUMZ 93599 with nine rather than ten infralabial scales; LSUMZ 93597 with slightly darker/grey wash on the subcaudal scales compared to the holotype; LSUMZ 93597 with 214 ventrals, 94 subcaudals; LSUMZ 93599 with 206 ventrals, 93 subcaudals, LSUMZ 93600 with 202 ventrals, 43 subcaudals (missing large portion of tail).

Coloration in life

Dorsal ground colour in life dark brown along the vertebral scale row and fading to yellowish lighter tan/light brown ventrally but with no distinct pattern down entire dorsal side of body and tail. Dorsum of head dark brown, ventrals and subcaudals cream with no patterns. Colour of iris in life dark brown-black.

Coloration in preservative

Overall coloration reddish brown in preservation and lighter in colour approaching the ventrals with no pattern down the dorsal side of body and tail. Colour of iris opaque grey in preservation. Dorsum of head, including rostral, internasals, prefrontals, frontal, supraoculars and parietals reddish brown. Supralabials one to five cream, with six to eight cream with a light wash of reddish brown infringing on the anterior of the scale where the supralabials come into contact with the temporals. Ventral scales cream with no pattern, subcaudals cream with no pattern. Ventral scales show iridescence under lights.

Etymology

The species epithet refers to the Admiralty Islands where this species is found, an archipelago of 18 islands to the north of New Guinea, comprising Manus Province, Papua New Guinea.

Natural history and distribution

As with all New Guinea Stegonotus , S. admiraltiensis sp. nov. is nocturnal. All four specimens were collected at night as they were moving on the forest floor on the leaf litter. Typical for Stegonotus , once picked up S. admiraltiensis sp. nov. rapidly attempted to bite the collector’ s hand and writhed violently in a side-to-side motion. Nothing more is known about the natural history or ecology of S. admiraltiensis sp. nov. Stegonotus admiraltiensis sp. nov. is found on the islands of Rambutyo and Los Negros in Manus Province of Papua New Guinea. Based on descriptions of similar specimens from Manus ( McDowell 1972) and recent collections there by SJR that will be registered in the near future ( Richards and Aplin 2015), we conclude that S. admiraltiensis sp. nov. is also found on Manus Island proper and that all specimens of Stegonotus from the Admiralty Islands are S. admiraltiensis sp. nov.

Comparisons

The Manus population of Stegonotus was thought to be conspecific with S. modestus ; however, in our phylogeny it is not sister to S. modestus ( Figure 3 View Figure 3 ). Due to the poorly supported node, it is unclear what the relationship of S. admiraltiensis is to other species in the genus. Stegonotus admiraltiensis sp. nov. differs morphologically from S. modestus by having no or little dark pigmentation on the subcaudal scales and in lacking extensive dark/grey pigmentation on the supralabial and infralabial scales, which is seen in some S. modestus . Stegonotus admiraltiensis also has two apicals pits on all or most dorsal scales, but these are absent in S. modestus . Superficially, S. admiraltiensis most closely resembles S. parvus . Both species are more tan/brown than the grey/black typical of most New Guinea Stegonotus ( Figure 2 View Figure 2 ), and they both have an unpatterned cream venter and no grey mottling on the labial scales. Apart from genetic differences, S. admiraltiensis differs from S. parvus in having apical pits on all or most dorsal scales, (absent in S. parvus ), as well as a higher number of ventral scales (202−214 in S. admiraltiensis versus 165−196 in S. parvus ).