Gegeneophis goaensis, Bhatta, Gopalakrishna, 2007

Bhatta, Gopalakrishna, 2007, A new species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) from Goa, India, Zootaxa 1409, pp. 51-59 : 51-57

Gegeneophis goaensis sp. nov.

( Figs. 1 , 2 , Table 1 )

Holotype: Bombay Natural History Society, Mumbai, India ( BNHS) 4594. A mature female, collected at Ganv Kond locality - 15o 36.80'N latitude 74o 04.46' E longitude (Keri Village, Sattari Taluk, North Goa district, Goa), September 2004.

Paratypes: BNHS 4595. A juvenile, same collection data as for the holotype. Zoological Survey of India, Calicut (ZSI/ WGFRS /V/A/608), mature male, collected at Ghoteli locality - 15o 36.44' N latitude and 74o 03.82' E longitude (Keri Village, Sattari Taluk, North Goa district, Goa), July 2006.

Diagnosis: A Gegeneophis differing from all other species in having a combination of more than 120 primary annuli, more than 75 of which are marked with secondary annular grooves. G. goaensis is a more slender species (length> 40 times greater than midbody width) than the only other Gegeneophis that have more than 50 secondary annuli ( G. danieli , G. nadkarnii ).

Description of the holotype: Some morphometric and meristic data are given in Table 1 . The specimen is a mature female. It is in good condition generally, but the skin throughout much of the body is slightly roughened due to dehydration. There is an artefactual ridge on the dorsal surface, commencing c. 58 mm from the snout tip. A midventral longitudinal groove of 145 mm length extends between the third nuchal groove and the vent. There is an 18 mm long midventral incision into the body cavity beginning 40 mm in front of the vent. Another incision of 12 mm is present commencing c. 85 mm from the snout tip. There are a few small scratches on the skin on both the dorsal and ventral surfaces (made during the search for scales).

The body in life is sub-cylindrical and slightly dorsoventrally compressed. The specimen measures 185 mm in length and 14 mm in circumference at midbody. The body is almost uniform in its width throughout the length. In the preserved specimen the body is 3.6 mm wide at the first annular groove and 4.3 mm at midbody in the broadest part. Thereafter the body gradually decreases in width to 3.0 mm just in front of the vent. In dorsal view, the head tapers strongly from the level of the occiput to the tentacular apertures. Anteriorly, the head tapers and terminates in a bluntly rounded but narrow snout tip. The posterior region of the head at jaw angle is slightly narrower than the nuchal region. Laterally the top of the head is straight and without any strong bulges. The margin of the upper lip slightly arched. The snout projects 0.6 mm beyond the mouth. The distance between the jaw angle and the top of the head (1.5 mm) is less than the distance between the jaw angle and the ventral surface of the lower jaw (1.6 mm). In ventral view, the anterior margin of the lower jaw is more broadly rounded than the anterior margin of the snout.

The minute sub-circular nostrils are slightly closer to the level of the snout tip (0.4 mm). The nostrils are 1.0 mm apart, visible dorsally and laterally but not ventrally. They are surrounded by a narrow whitish rim. In life, the tentacles are globular. The tentacular apertures are lateral in position and 2.5 mm apart. They are situated at a distance of 1.4 mm from the tip of the snout and 0.8 mm from the nostrils. The slightly raised tentacular apertures are visible in both dorsal and ventral views. They are much closer to the margin of the upper lip (0.3 mm) than to the top of the head (0.7 mm). The eyes that are situated under bone are visible to the naked eye (and clearly visible in photographs) in life but not in the preserved specimen.

We counted 18 premaxillary-maxillary, 19 vomeropalatine, 17 dentary, and 4 splenial teeth. The teeth in all four series are recurved and monocusped. They are smaller posteriorly than anteriorly. The posteriormost teeth of the premaxillary-maxillary and vomeropalatine series are almost parallel. The vomeropalatine series lacks diastemata. Both in the upper and lower jaw the teeth of the outer rows are markedly larger than those of the inner rows. The premaxillary-maxillary and vomeropalatine tooth rows clearly extend posterior to the choanae. When viewed anteriorly, the dentary teeth appear largest, followed by the premaxillary-maxillary and vomeropalatine teeth in decreasing order of the size. The splenials are the smallest.

The choanae are small, sub-circular and are separated by a distance of approximately two times the width of each choana.

The tongue is broadly rounded in dorsal view and unattached anteriorly. The anterior end of which, lies close to the splenial teeth. It is separated by a groove from the gingivae. The narial plugs are situated far anterolaterally close to the edge of the tongue and have encircling grooves. The posterior part of the dorsal surface of the tongue behind the narial plugs and the anterior surface to it is uniform whitish colour.

The nuchal region is broader and higher than the adjacent parts of the body. The two nuchal collars are marked clearly by three nuchal grooves. The nuchal region at the first nuchal groove (3.6 mm) is slightly broader than the back of the head at the jaw angle (3.4 mm) but the width of the body at the first annular groove (3.6 mm) is equal to the width at the first nuchal groove. The first collar (1.2 mm) is shorter than the second (2.0 mm) laterally. The nuchal grooves are complete around the nuchal region with the exception of the third nuchal groove, which is incomplete midventrally. The first collar bears one short transverse groove middorsally. The second collar also bears a middorsal transverse groove that extends almost fully across the dorsal surface. Although the nuchal and annular grooves are mostly perpendicular to the long axis of the body, the third nuchal groove and the posterior grooves of the first two primary annuli are slightly angulate anterodorsally. On the ventrolateral surface, the free ends of the third nuchal groove bend slightly posteriorly.

The annuli are marked by whitish coloured grooves, which are more conspicuous posteriorly. There are 125 primary annuli. Primary annular grooves are complete middorsally on the 1st and 2nd primary annuli, and from the 39th primary onwards, but they are incomplete middorsally on primary annuli 3 to 38. The secondary annular groove appears for the first time on right side of the 48th primary annulus dorsolaterally, but it is not seen in the 49th primary annulus. The secondary grooves are middorsal from 50th to 55th primary annuli with the exception of 51 and 53 where secondary annular grooves are not seen. 56th primary annulus also is without secondary annular groove. From 57 to 115, secondary annular grooves are middorsal in position extending gradually on both sides. The secondary grooves extend across the midline on the ventral surface and become complete from the 116th primary annulus up to the sub-circular disc surrounding the vent. The sub-circular disc is 1.0 mm wide, 0.7 mm long. The rounded terminus ends in a cap that is completely demarcated by the last primary annular groove. The transverse vent is 0.4 mm wide. The vent is surrounded by eight denticles. Nine secondary grooves in front of the vent are complete. There are 78 primary annuli with secondary grooves.

Scales were sought at three different points along the body both dorsally and ventrally. No scales were found anterior to the 50th primary annulus. On the 60th primary annulus oval scales were found only on the dorsal surface in four rows. On the posterior primary annulus, where the secondary annular grooves become complete ventrally, scales occur in four rows on the dorsal and two rows on the ventral surface.

In life, the holotype was a fleshy-brown on its anterior two thirds of the body, which gradually merged with the dark brown of the posterior one third. The colour of the body was almost uniform on both dorsal and ventral surfaces. The annuli were more prominent in the posterior one-third, comparatively less prominent in the anterior one third and moderate in the middle of the body. The head was pinkish brown in colour. A creamy white patch extends from behind the eyes to just in front of the tentacular apertures. The rims of both upper and lower jaws were lighter than the dorsum of the head. The skin contains whitish glands throughout the body which were more prominent on the posterior one third.

In preservation, the body is blackish grey on the dorsal surface which merges gradually with the light grey on the ventral surface. The annular grooves are of whitish colouration and more prominent laterally. The entire dorsal surface of the head including the snout tip is light cream coloured. The under surface of the lower jaw is yellowish white in colour up to the second nuchal groove. The disc surrounding the vent is whitish both in life and preservation.

Paratypes: Morphometric and meristic data for the type series are given in Table 1 . The paratypes are very similar to the holotype. The paratypes are in good condition generally. Specimens range in size from 133 mm (BNHS 4595) to 220 mm (ZSI/WGFRS/V/A/608) in length and 9 to 15 mm in circumference respectively at midbody. Sex was determined by examining gonads. Both the paratypes resemble the holotype in the pattern of nuchal grooves; width of disc surrounding vent; width of vent; in number of denticles surrounding the vent; recurved and monocusped teeth in all four series; lacking diastemata. In having markedly larger outer rows of teeth in both upper and lower jaws than the inner rows; largest dentary teeth followed by the premaxillarymaxillary and vomeropalatine teeth in decreasing order of the size and smallest splenials, the paratypes are similar to the holotype.

Distance between jaw angle and ventral surface of lower jaw 1.6 1.2 1.5 Total number of primary annuli with secondary grooves 78 82 89

Paratype BNHS 4595 is an immature specimen (neither ova nor testes could be identified), dorsolaterally compressed with an artefactual 105 mm long midventral groove, beginning c. 8 mm from tip of the ventral surface of the lower jaw. There is a 9 mm long midventral incision in to the body cavity beginning 60 mm in front of the vent. In preserved specimen body is 2.6 mm at the first annular groove and 3.3 mm at midbody in the broadest part and width at the level of vent is 1.9 mm. There are 126 primary annuli and 82 of these have secondary grooves. Primary grooves are incomplete dorsally only on the 4th and 5th primary annuli and are middorsally complete from 1st to 3rd and from 6th primary annulus onwards. Secondary grooves ‘start’ dorsolaterally on both sides from the 45th primary annulus and continue middorsally from 48th primary annulus back along the body. The secondary grooves extend across the midline on the ventral surface and become complete from the 116th primary annulus onward. Nine secondary annular grooves in front of the vent are complete. We counted 17 premaxillary-maxillary, 18 vomeropalatine, 17 dentary and 4 splenial teeth. No scales could be found.

Paratype ZSI/WGFRS/V/A/608 is a mature male, slightly dorsolaterally compressed with a sub-cylindrical body. There is an artefactual middorsal groove of 4 mm, beginning c. 4 mm behind the snout tip, and a midventral groove 148 mm long beginning c. 10 mm behind the tip of the ventral surface of the lower jaw. There is an 18 mm long midventral incision into the body cavity beginning 25 mm in front of the vent. There are 126 primary annuli, 89 of which have secondary annular grooves. Primary grooves are complete middorsally on the 1st and 2nd primary annuli and from 39th primary annulus onwards, but incomplete middorsally from the 3 to 38. Secondary grooves ‘first appear’ dorsolaterally on the 38th primary annulus on the left side. On the 39th primary annulus secondary groove is on the right side dorsolaterally. Secondary grooves are not seen on 40th and 41st primary annuli. From 42nd primary annulus onwards secondary grooves are middorsal. Secondary grooves extend across the midline on the ventral surface from the 112th primary annulus to become complete. Eleven secondary annular grooves in front of the vent are complete. We counted 16 premaxillarymaxillary, 20 vomeropalatine, 16 dentary teeth and only 1 splenial tooth. No scales were observed at the 25th or 40th primary annulus. On each of the 50th and 60th primary annuli four dorsal rows of scales were found, but none were found ventrally. Where the secondary annular grooves become complete ventrally, scales occur in four rows on the dorsal and two rows on the ventral surface.

Ecology and habitat: The holotype and smaller of the two paratypes were collected from rotting vegetation at the base of saplings c. 5 m from a small river (Kalti) in a mixed orchard of arecanut, banana, coconut, acacia and pepper. The locality is 32 m above sea level. The soil where the specimens were collected was black and rich in mixed compost and rotten waste, temperature 32o C (at 30 cm depth), humidity 87% and canopy cover around 55%. The larger paratype was collected from underneath piles of rotting coconut leaves c. 20 m from a small rivulet (Angadiho Vahal) in a coconut orchard at 42 m above sea level. The soil was lateritic, mixed with clay, temperature 30o C (at 30 cm depth), humidity 70% and canopy cover around 30%.

Comparison with congeneric species: The numbers of primary and secondary annuli are important characters differentiating the species of Gegeneophis (e.g. Giri et al. 2003). G. goaensis differs from all other species of Gegeneophis except G. krishni and G. seshachari in having more than 120 primary annuli, but it is easily distinguished from these because the latter two have no ( seshachari ) or fewer than 20 ( krishni ) of their primaries bearing secondary grooves. Indeed, only G. goaensis , G. danieli and G. nadkarnii among the nine species of Gegeneophis have more than 50 primary annuli bearing secondary grooves. G. goaensis is readily distinguished from G. danieli and G. nadkarnii in being more slender (superficially earthworm-like). Additionally, the latter two species have some secondary grooves on the anteriormost primary annuli, whereas in G. goaensis they ‘begin’ no further forwards than the 40th primary. G. danieli has more premaxillary-maxillary teeth (30 versus 18) than G. goaensis . We are convinced that these differences are sufficient to warrant description of the new species. As with many caecilians, several species of Gegeneophis are known from small samples and few localities and our very rudimentary understanding of intra-specific will probably need to improve as additional species are recognized.

Etymology: The species is named after Goa where the type locality is situated.

Figures

FIGURE 1. Photograph of the paratype of Gegeneophis goaensis (ZSI / WGFRS / V / A / 608) in life

FIGURE 2. a. Dorsolateral view of the head, b. Ventral view of the body terminus (Photographs of the paratype of Gegeneophis goaensis ZSI / WGFRS / V / A / 608 in life)

Tables

TABLE 1. Some morphometric (in mm) and meristic data for type series of Gegeneophis goaensis. Measurements were made to the nearest 0.1 mm with dial calipers, except for length and circumference, which were measured with a ruler and a piece of thread.

Total length	Holotype (BNHS 4594) 185	Paratype (BNHS 4595) 133	Paratype (ZSI/WGFRS/V/A/608) 220
Head length	3.7	2.7	4.0
Head width at jaw angle Circumference at midbody	3.4 14	2.5 9	3.5 15
Width of the body at 1st annular groove Width of the body at broadest region	3.6 4.3	2.6 3.3	3.8 4.5
Width of the body at the level of vent	3.0	1.9	3.2
Length divided by width Length of the snout projecting beyond mouth	43.0 0.6	40.3 0.7	48.8 0.7
Distance between jaw angle and top of head	1.5	1.3	1.4