Chikila alcocki, Kamei, Rachunliu G., Gower, David J., Wilkinson, Mark & Biju, S. D., 2013

Kamei, Rachunliu G., Gower, David J., Wilkinson, Mark & Biju, S. D., 2013, Systematics of the caecilian family Chikilidae (Amphibia: Gymnophiona) with the description of three new species of Chikila from northeast India, Zootaxa 3666 (4), pp. 401-435 : 403-409

Chikila alcocki sp. nov.

( Figures 1 , 2 , 3 A, 4A, 5A, 6A and 7; Tables 1–6)

Chikila sp.: Kamei et al. (2012) (in part)

Holotype. ZSI A11539 , female, collected 26 June 2007 by RGK & SDB from Dhyütere (25.91528 N, 94.10528 E; 782 m asl), New Sendenyu village, Tseminyu subdivision, Kohima district, Nagaland, India.

Paratypes. BNHS 5523, ZSI A11544 collected with the holotype; ZSI A11540, collected 26 June 2007 from Dhyütere 1; BNHS 5520, collected 27 June 2007 from Paraseng 1 (ca. 1 km from the type locality); BNHS 5519, BNHS 5525, collected 0 2 October 2007 from Kenrunhü (less than 1 km from the type locality); BNHS 5524, collected 23 October 2007 from Dhyütere 2. All specimens collected by RGK & SDB.

Referred specimens. BNHS 5521, collected 22 June 2008 by DG, MW, RGK & SDB from Khotlo (Shongnga); ZSI A11538, collected 24 June 2008 by DG, MW, RGK & SDB from Humlu; BNHS 5522, collected 21 July 2009 by RGK & SDB from Sipanullah; BNHS 5526, SDB.DU 2009.743, collected 21 July 2009 by RGK & SDB from Sipanullah 1; SDB.DU 1613, collected 23 June 2008 by DG, MW, RGK & SDB from Api 1; SDB.DU 1662, collected 26 June 2008 by RGK & SDB from Dhyütere 1.

Locality Altitude Coordinates Species recorded

Latitude (N) Longitude (E) ARUNACHAL PRADESH

East Kameng district

Darlong , Seijosa 121 26.93722 92.99611 C. darlong sp. nov. Darlong 1, Seijosa 122 26.93750 92.99333 C. darlong sp. nov. PTR, Seijosa 125 26.93694 92.98194 C. darlong sp. nov. PTR 2 (Jaali nullah 2), Seijosa 254 26.95889 92.95694 C. darlong sp. nov. PTR 3 (Jaali nullah 3), Seijosa 261 26.95528 92.95361 C. darlong sp. nov. Changlang district

Sipanullah, Bhoddisatta 365 27.51900 96.36712 C. alcocki sp. nov Sipanullah 1, Bhoddisatta 372 27.51917 96.36762 C. alcocki sp. nov...... continued on the next page Diagnosis. A Chikila that differs from all congeners in its relatively unicoloured (weakly bicolored anteriorly) adult colour pattern (vs. moderately bicoloured in C. darlong and C. fulleri , strongly bicoloured in C. gaiduwani ), weakly marked AGs (vs. moderately marked in C. darlong , C. gaiduwani , strongly marked in C. fulleri ), and relatively narrow choanae (vs. small in C. darlong and C. fulleri , large in C. gaiduwani ).

Description of the holotype ( Figures 4 A and 7). Some morphometric and meristic data are given in Tables 3A and 4 . In good condition; two midventral incisions, one ca. 10 mm close to midbody, one extending for ca. 50 mm from ca. 25 mm anterior to vent; one posterior scale pocket open dorsally; short artificial transverse crease in front of NG1 (mouth open); artefactual longitudinal ridges on anterior of body; broken vertebral column approximately halfway; slightly dehydrated; terminus dented. Female with yolky ova, largest 3.8 x 1.8 mm.

Body slightly tapering on anterior half, dorsoventrally flattened throughout, slightly less so on posterior half; L/W = ca. 25. In dorsal view, sides of head straight, converging steadily to level of TAs, rapidly between TAs and snout tip. In lateral view, top of head straight to weakly convex; upper lip weakly concave with apex slightly closer to level of eye than TA; lower jaw approximately same height as upper jaw at CM. In ventral view, lips notably more blunt anteriorly than ST. Eyes not visible. TAs barely elevated, visible ventrally (not dorsally), positioned just below imaginary lines between nares and CMs. Nares just visible ventrally, not dorsally. Teeth of inner series approximately half as small as those of outer series; VP series forming narrowly curved (somewhat angulate) arc anteromedially; projection of snout beyond anterior of mouth almost twice the distance between VP and PM series anteriorly. Choanae subcircular, smallest distance between them approximately 2.5 times the width of each at that point; valves just visible. Gap between anterior tip of tongue and IMs or between lateral margins of tongue and OMs narrow to absent, some IMs overlapping tip of tongue. Narial plugs with some irregular dark patches, flaplike, extend very slightly beyond tongue margin, separated from body of tongue by deep grooves, except posteriorly. Tongue with short median groove posteriorly, some small lateral grooves.

Nuchal region not notably more massive than adjacent body or back of head. NG1 and NG2 completely encircling body, both curving slightly anteromedially on dorsum; C2 with one long TG; one dorsal transverse crease behind TG on C2 and one in front. AGs mostly complete middorsally except for middle third of body where incomplete or very faintly marked; ventrally AGs mostly incomplete along midline, more widely so on anterior half, a few complete posteriorly. Posterior edges of most PAs slightly raised. Many anterior PAs with one or more transverse, predominantly dorsolateral creases. Anteriormost SAGs short, dorsolateral, on both sides of 74th PA; SAGs middorsally complete from 78th PA, ventrally complete from 85th PA. Vent region interrupts last four or five AGs. Vent in ovate (wider than long), fairly discrete disc with 10 denticulations, 3 of which partially subdivided. Two main rows of substantially overlapping scales present dorsally in posterior (87th PA) of body in pocket approximately half-length of PA. Scales here irregular, squarish (0.8 mm).

C. gaiduwani C. darlong C. fulleri C. alcocki C. gaiduwani 0–0.003, mean = 0.001

(n = 11) (n = 55)

C. darlong 0.067–0.068, mean = 0.067 0–0.003, mean = 0.002

(n = 6) (n = 66) (n = 15)

C. fulleri 0.084–0.088, mean = 0.086 0.089–0.092, mean = 0–0.015, mean = 0.008 (n = 13) (n = 143) 0.09 (n = 78) (n = 78) C. alcocki 0.094–0.098, mean = 0.096 0.1–0.105, mean = 0.102 0.092–0.099, mean = 0–0.013, mean = (n = 13) (n = 143) (n = 78) 0.095 (n = 169) 0.007 (n = 78) Weakly bicoloured anteriorly, more weakly so posteriorly; dorsally dark grey, ventrally brown-grey with intermittent, weak darker midventral line; slightly darker on last tenth of body. Dorsal grey to ventral grey transition gradual (less so posteriorly), at a short distance above halfway down flank; ventral brown-grey pales very slightly ventrally. Top of head not notably darker than body. Midline of lower jaw with narrow, anterior projection of same brown-grey as body; lateral to this a grey V, a whitish V and then pale grey bordered by whitish edge to lower lip. TAs in whitish spot that extends back as narrower pale stripe to expected position of eye. Nares in broad whitish blotches that meet anteriorly at pale snout tip. To unaided eye, AGs distinct, dark except immediately anterior to vent where whitish. Microscopically, AGs laterally with whitish edge, giving way to darker very narrow aglandular posterior margins of annuli; ventrally, a thicker dark band just behind anterior edge of annuli extending across midline even where AGs incomplete. Disc surrounding vent unpigmented; narrow strip (slightly less than length of secondary annulus) immediately anterior to disc also unpigmented. Tongue unpigmented.

In life ( Figure 4 A), dorsally dark lilac, slightly darker in the last one-fourth of the body, ventrally slightly paler. Head slightly paler than body with some white patches; lips, areas around CMs and snout tip whitish; nares in broad whitish blotches that meet anteriorly at pale snout tip; lower jaw bears a thick whitish V in ventral view, not reaching whitish margins of lips.

Variation and additional information from the paratypes and referred specimens. Some morphometric and meristic data are given in Tables 3A and 4 . Noteworthy differences from the type include the following. Anterior body tapering less apparent in thinner animals (e.g., BNHS 5524, ZSI A11540). In BNHS 5525 the upper lip is barely concave, with the apex almost below the TA. CM slightly less far from bottom than top of head in lateral view in BNHS 5524. TAs mostly touching imaginary lines between nares and CMs, a little variation in their degree of elevation. Collars more massive than adjacent body and head in BNHS 5524, BNHS 5525 and SDB.DU 1613. Longitudinal line or crease on throat never extends to posterior half of C1 (in SDB.DU 2009.743 and BNHS 5521, the line or crease extends up to posterior groove of C1). In most specimens the region in which AGs are incomplete dorsally is larger, approaching half the total length, and AGs are most widely incomplete ventrally approximately at midbody. Skin smooth on most specimens, with irregular creases on some. Pale patch in front of disc biggest (ca. equal to length of one PA) in ZSI A11540, about half a PA in BNHS 5520 and ZSI A11544, small in BNHS 5525, barely noticeable in BNHS 5519. Top of head notably greyer than body in SDB.DU 1613, ZSI A11544 and BNHS 5523, and with a paler central patch in BNHS 5520 and BNHS 5524. BNHS 5519, BNHS 5525 and ZSI A11538 are more or less unicoloured, not noticeably darker posteriorly, and lack a dark midventral line. In some specimens (e.g., BNHS 5525, ZSI A11540) anterior of head quite pale, with pale spots around nares and TAs connected. Curve in VP series anteriorly less angulate with slight indentation laterally in BNHS 5520 and BNHS 5523. Choanae generally ovate and separated mostly by a little more than 2.25 times width of a single choana. Narial plugs generally not flap-like, may not extend beyond tongue (e.g., BNHS 5520, BNHS 5524), pigment not always apparent, but present on whole anterior of tongue in BNHS 5523. Median tongue groove present or absent. Snout projecting in front of mouth compared to the distance between anterior PM and VP series variable, about equal in BNHS 5525. In ZSI A11538, scales present on last third of body, commencing between 65th to 70th PA; on 70th PA few, only on lateral side of body; at 88th PA longer (1.1 mm) than wide (0.8 mm) in three rows dorsally; three to four rows of slightly smaller (1.1 x 0.7 mm) scales on venter, in pockets approximately half-length of PA. In BNHS 5526, scales commencing at ca. 82nd PA, few, isolated, tiny, only on dorsum; on 89th PA three rows, small, round (0.6 x 0.6 mm) dorsally, pocket half-length of PA; two to three rows on venter in pocket slightly less than half-length of PA. In BNHS 5520, commencing between 70th to 74th PA; on 74th PA two to three rows, small, isolated; on 85th PA two to three rows dorsally and ventrally.

Etymology. Named in honour of Alfred William Alcock (1859–1933), former Superintendent of the Indian Museum, who described ‘Herpele’ fulleri ( Chikila fulleri ). The species name alcocki is a noun in the genitive case.

Suggested English common name. Alcock’s chikila .

Distribution and natural history. Chikila alcocki sp. nov. is currently known from the type locality Dhyütere and its vicinities in New Sendenyu village, Tseminyu, Kohima district, from Mon district in Nagaland, and from Changlang district of Arunachal Pradesh ( Figure 1 ; Table 1). The type series and one referred specimen (SDB.DU 1662) were collected from slushy soil at the edges of rice paddies, banana plantation and jhum fields; soil was silty clay loam. The referred specimen SDB.DU 1613 was collected along the sides of artificial water canals that fed paddy fields; BNHS 5521 and ZSI A11538 were collected in disturbed secondary forest bordering agricultural fields; BNHS 5522, BNHS 5526 and SDB.DU 2009.743 were collected near seepage-fed puddles inside disturbed secondary forests near Namdapha National Park. The species is known from altitudes of 320–900 meters asl and was fairly abundant at the type locality.

Remarks. Summary comparisons are provided in Tables 5 and 6 . Beyond the differences given in the diagnosis, the examined material of C. alcocki differs from C. darlong in: having a less pointed head in dorsal view; externally invisible eyes; similar numbers of VPs and PMs (vs. fewer VPs than PMs). Chikila alcocki differs from C. fulleri additionally in: lacking pale blotches on the chin, throat and underside of anteriormost annuli; having a more extensive (length and breadth) pale eye-TA patch, generally encircling and extending behind the eye; having an unpigmented disc and patch anterior to disc; having an anteriorly less angulate VP series; having a broader head in dorsal view; having relatively lower TAs, imaginary naris-TA line crosses upper lip halfway (vs. one quarter) between CM and AM. Chikila alcocki differs from C. gaiduwani additionally in its less broadly rounded snout in dorsal view.

The uncorrected mean divergences (16S and cox1 genes) between Chikila alcocki and C. darlong , C. fulleri and C. gaiduwani are 10.2%, 9.5% and 9.6%, respectively ( Table 2).

The data suggest also that Chikila alcocki might differ from C. darlong in having relatively fewer SAGs, having a proportionately shorter head, and attaining a greater maximum length; from C. fulleri in having a less attenuate body and relatively shorter, broader head; and from C. gaiduwani in having relatively fewer SAGs.

Figures

FIGURE 1. Northeast India showing the distribution of the genus Chikila. Positioning of locality dots is approximate; for exact coordinates, see Table 1.

FIGURE 2. DNA phylogeny of Chikila based on the analysis of 1,982 base pairs (bp) of mitochondrial (mt) sequence data comprising a 696 bp long fragment of mt cytochrome oxidase 1 (cox 1), and two (non-overlapping) fragments of mt small subunit ribosomal DNA (16 S) of 463 and 823 bp. Numbers at nodes are support values for Maximum Likelihood (ML) and Bayesian inference (BI) analyses (see Kamei et al. 2012 for details).

FIGURE 3. Midbody (lateral view) of Chikila species skinned and unskinned to show the pigmentation of the annular grooves and of septa in the underlying musculature. A. Chikila alcocki sp. nov. (SDB. DU 1662), B. Chikila darlong sp. nov. (SDB. DU 1695), C. Chikila fulleri (SDB. DU 1304), D. Chikila gaiduwani sp. nov. (SDB. DU 1560). Scale bar: 10 mm.

FIGURE 4. Holotypes in life. A. Chikila alcocki sp. nov. (ZSI A 11539), B. Chikila darlong sp. nov. (ZSI A 11546).