Typhlops andasibensis, Wallach, Van & Glaw, Frank, 2009

Wallach, Van & Glaw, Frank, 2009, A new mid-altitude rainforest species of Typhlops (Serpentes: Typhlopidae) from Madagascar with notes on the taxonomic status of T. boettgeri Boulenger, T. microcephalus Werner, and T. capensis Rendahl, Zootaxa 2294, pp. 23-38 : 24-28

Typhlops andasibensis sp. nov.

Figs. 1–4

Typhlops cf. domerguei — Glaw & Vences, 1994: fig. 357.

Typhlops sp. “Andasibe” — Glaw & Vences, 2007: 445, fig. 8.

Holotype. ZSM 54/2005 (field number ZCMV 2255), an adult female, collected on 23-26 February 2005 near Andasibe (= Perinet), 18°56.169'S, 48°24.734'E, 939 m elevation, central eastern Madagascar, in pitfall lines installed by the NGO "Mitsinjo" and its president Rainer Dolch.

Paratypes. ZSM 53/2005 (field number ZCMV 2287), an adult female, and UADBA uncatalogued (field number ZCMV 2256), same data as holotype; ZFMK 59787, an adult female, collected 24–28 February 1994 near the train station of Andasibe by F. Glaw; MRSN R1153 (field number FN 6296), an adult male, collected on 2 December 1996, near Andasibe, by F. Andreone.

Diagnosis. Typhlops andasibensis sp. nov. can be distinguished from all other Typhlops by the combination of 26 midbody scale rows, 373–381 total middorsal scales, a slightly trilobed snout in dorsal profile, a rounded snout in lateral profile, a T–V supralabial imbrication pattern, transversely enlarged frontal, postfrontal and interparietal scales, inferior nasal suture contacting second supralabial, and an incomplete superior nasal suture. Within Madagascar, T. andasibensis sp. nov. can be separated from all other typhlopids by the combination of 26 midbody scale rows, less than 400 middorsals, and a T–V supralabial imbrication pattern.

Description of holotype. The holotype (ZSM 54/2005) has a snout-vent length of 317.5 mm and an overall length of 325 mm. With a midbody diameter of 11.9 mm, the width of the relatively stout body is contained in its length 27.3 times. The tail is short, 2.3% of the total length, and about as broad as long; its length is 7.5 mm and its midtail diameter is 6.8 mm, resulting in a TL/W ratio of 1.1. The nuchal diameter is 7.3 mm and the precloacal diameter is 10.4 mm; the body thus tapers anteriorly and posteriorly in thickness. A minute terminal spine is present that extends horizontally, as does the tail which lacks a terminal ventral curvature.

The longitudinal scale row formula includes 24 anterior rows, 26 rows at midbody, and 24 precloacal scale rows. Total middorsal or transverse scale rows, counted between the rostral and terminal spine, are 377. There are 8 subcaudal scales. Five anal scales are present. All body scales have rounded posterior borders.

The head is slightly narrower than the neck, tapering in dorsal profile to a rounded but slightly trilobed snout. The rostral, oval in shape and 0.4 of the diameter of the head, reaches beyond the level of the eyes and possesses a tapered posterior edge. The frontal, postfrontal, and interparietal are hexagonal and transversely enlarged, twice the size of the body scales. The supraoculars and parietals are also enlarged to the same extent and oriented obliquely to the body axis. The lateral edge of the supraocular is wedged between the dorsal margins of the preocular and ocular. There is a pair of transversely elongated occipitals, one and a half times the width of the body scales.

The snout is rounded in lateral aspect. The nostril's axis is oriented vertically, directed laterally, and midway between to the rostral and preocular. The inferior nasal suture contacts the second supralabial; superior nasal suture is incomplete, extending dorsomedially across 0.67 of the nostril-rostral gap. The nasal exhibits a moderately concave posterior border. The preocular is single and slightly wider than the nasal. The ocular is one and a half times wider than either the preocular or nasal, broadest medially and tapering ventrally. The eye is small with a discernible pupil and is located beneath the preocular-ocular border. There are four supralabials, each one larger than the one preceding with the fourth more than twice as large as the third. Three postoculars occur between the parietal and fourth supralabial on each side. The supralabial imbrication pattern is type T–V with both the second and third supralabials posteriorly overlapping the anterior margins of the preocular and ocular, respectively.

A radiograph ( Fig. 3 ) reveals that there are 198 total vertebrae (186 costals and 12 caudals with 5 pairs of lymphapophyses); the costal/vertebral ratio is 1.90:1. As with all Typhlopidae , the atlas and axis are devoid of ribs and the third vertebra supports the first pair of ribs.

In preservative, the dorsum and venter are brown, each scale with a brown base and clear posterior edge. A thick yellow ring of glands present on the rostral. The snout and lower lateral head are yellow in addition to a yellow nuchal collar three scales wide, small midventral yellow spots covering 1–3 scales that form a broken stripe, yellow precloacal region, and the entire ventral tail is yellow.

Variation. See Table 1 for morphometric variation in the type series of Typhlops andasibensis sp. nov. The single male specimen (MRSN R1153) differs slightly from the females in having a lower middorsal scale count (306 vs. 320–340), higher number of nuchal scale rows (26 vs. 24), fewer postoculars (2 vs. 3), narrower rostral (0.3 vs. 0.4), and broader parietals (3 vs. 2), some or all of which may be attributable to sexual dimorphism. Conversely, it is possible that the male represents a separate species.

There are 194 vertebrae in the paratype ZSM 53/2005 (180 costals and 14 caudals with 5 lymphapophyses); the costal/vertebral ratio is 1.92:1.

Internal anatomy. Based upon one male and two female paratypes. Table 2 summarizes visceral differences and similarities in the type series; Table 3 compares Typhlops andasibensis sp. nov. with other Malagasy and Comoro species.

The only other Malagasy species for which C/V ratio data are available are Typhlops boettgeri with a ratio of 1.86:1 ( Alexander & Gans, 1966), Xenotyphlops grandidieri with a ratio of 1.79:1 ( Wallach & Ineich, 1996), and Ramphotyphlops braminus with a ratio of 1.63–1.87 ( Roux-Estève, 1974; Ota et al., 1993). The C/ V ratio of 1.90–1.92:1 is thus similar to the other Malagasy species and falls within the range for all typhlopid species examined of 1.5–2.3:1 ( Alexander & Gans, 1966).

Comparisons. See Table 3 and 4 for comparison with other Malagasy and Comoro species.

Etymology. The specific epithet refers to the type locality.

Suggested common name. Andasibe Blind Snake.

Natural history. The holotype and two of the paratypes (from ZSM and UADBA) were collected in pitfalls in primary rainforest within a period of few days in the rainy season (February 2005), indicating that T. andasibensis sp. nov. is moderately common at the type locality. Other reptiles collected with these pitfalls were the snake Exallodontophis albignaci , and many skinks representing five species of the genera Amphiglossus and Madascincus . Paratype ZFMK 59787 was collected during the day, active on the ground, in the leaf litter of disturbed primary rainforest, just a few hundred meters from the train station of Andasibe during dry weather. Further road-kills were observed or collected by Rainer Dolch (pers. comm.) on the road between the "Route Nationale" and the train station of Andasibe. Despite its obvious moderate abundance, we discovered only one single living specimen by opportunistic searching during many (day and night) surveys around Andasibe between 1987 and 2005 at different seasons and weather conditions. The three other specimens were captured in pitfalls within a few days in 2005, indicating the inefficiency of the opportunistic searches for surveying typhlopids. These observations might further suggest that T. andasibensis sp. nov. is generally hidden below the leaf litter and only rarely active on the ground.

Distribution. Until now Typhlops andasibensis sp. nov. is known only from the forests along the road between the Hotel "Feonnyala" and the train station of Andasibe.

Figures

FIGURE 1. Typhlops andasibensis sp. nov., dorsal view of head of paratype, ZSM 53 / 2005.

FIGURE 2. Typhlops andasibensis sp. nov., lateral view of head of paratype, ZSM 53 / 2005.

FIGURE 3. Typhlops andasibensis sp. nov., radiograph of the holotype (ZSM 54 / 2005).

FIGURE 4. Typhlops andasibensis sp. nov., dorsal view of paratype ZFMK 59787.

Tables

TABLE 1. Morphometric data of available specimens of the Typhlops andasibensis sp. nov. type series. Mus. = museum deposition, No. = catalogue number, TS = type status (HT = holotype, PT = paratype), LOA = total length (mm), MBD = midbody diameter (mm), L / W = length / width ratio, TL = tail length (mm), RTL = tail length / total length, TL / W = tail length / midtail width, LSR = longitudinal scale rows, TMD = total middorsals, SC = subcaudals, RW = midrostral width / head width at eye level, NS = superior nasal suture, PO = postoculars, PAR = parietal enlargement (times body scale), OCC = occipital enlargement.

Mus.	No.	TS	Sex	LOA	MBD	L/W	TL	RTL	TL/W	LSR	TMD	SC	RW	NS	PO	PAR	OCC
ZSM	54/2005	HT	F	325	11.9	27.3	7.5	2.3	1.1	24-26-24	377	8	0.39	0.67	3/3	2.0	1.5
ZSM	53/2005	PT	F	340	12.1	28.1	8.5	2.5	1.3	24-26-24	373	10	0.40	0.67	3/3	2.0	2.0
ZFMK	59787	PT	F	320	11.5	27.2	6.0	1.9	0.9	24-26-24	381	8	?	?	3/3	?	?
MRSN	R1153	PT	M	306	11.0	27.8	9.0	2.9	1.4	26 - 26-24	380	11	0.29	0.50	2/2	3.0	2.0