Gegeneophis madhavai , Bhatta, Gopalakrishna & Srinivasa, R., 2004

Bhatta, Gopalakrishna & Srinivasa, R., 2004, A new species of Gegeneophis Peters (Amphibia: Gymnophiona: Caeciliidae) from the surroundings of Mookambika Wildlife Sanctuary, Karnataka, India, Zootaxa 644, pp. 1-8: 2-7

publication ID

10.5281/zenodo.158094

publication LSID

lsid:zoobank.org:pub:35DD5003-1DBC-46B4-AEDA-C2200BC352DA

persistent identifier

http://treatment.plazi.org/id/038387C8-2B66-2001-FEC2-346B53010A41

treatment provided by

Plazi

scientific name

Gegeneophis madhavai
status

sp. nov.

Gegeneophis madhavai  sp. nov.

( Figs. 1, 2 View Figure , Table 1)

Holotype: Bombay Natural History Society, Mumbai, India ( BNHSAbout BNHS 4235). A mature male, collected at Doddinaguli locality (Mudur Village, Kundapura Taluk, Udupi District, Karnataka State) in August 2001. The village is situated adjacent to the Mookambika Wildlife Sanctuary, in the Western Ghats.

Paratype: Zoological Survey of India, Calicut (ZSI, Calicut: V/A/ 574). A mature male, with collection data as for the holotype.

Diagnosis: A large Gegeneophis  differing from all other species in having ‘visible eyes in life’, fewer than 100 primary annuli and more than 25 secondary annuli that are confined to the posterior of the body. These features are found in other species, but not in this unique combination.

holotype paratype

Distance between jaw angle and ventral surface of lower jaw 2.9 3.0 Distance between jaw angle and snout tip 7.0 6.1 Distance between jaw angle and tip of lower jaw 5.9 5.1 Distance between nostrils 2.0 1.8 Distance between nostril and snout tip 0.8 1.0 Distance between tentacles 3.8 3.7 Distance between tentacle and snout tip 2.8 2.5 Distance between tentacle and jaw angle 4.1 3.7 Distance between tentacle and nostril 1.4 1.4 Distance between tentacle and margin of upper lip 0.5 0.6 Distance between tentacle and top of head 1.2 0.9 Width at 1 st nuchal groove 7.8 7.8 Width at 2 nd nuchal groove 8.5 8.6 Width at 3 rd nuchal groove 9.2 8.3 Length of 1 st nuchal collar (laterally) 2.0 2.2 Length of 2 nd nuchal collar (laterally) 2.5 2.9 Distance between snout tip and 1 st nuchal groove 9.1 7.5 Distance between snout tip and 2 nd nuchal groove 11.1 9.7 Distance between snout tip and 3 rd nuchal groove 13.6 12.6 Total number of primary annuli 97 96 Total number of secondary annuli 35 27 Anteriormost primary annulus with secondary groove 63 rd 70 th Number of complete secondary annuli in front of vent 7 5

Description of the holotype: Morphometric and meristic data are given in Table 1. The specimen is in good condition. The holotype measures 256 mm in length and 34 mm in circumference at midbody. There are four artefactual transverse ridges on the dorsal surface, commencing c. 22 mm from the snout tip. A midventral longitudinal groove of 210 mm length extends between the third nuchal groove and the vent. There is a 44 mm long midventral incision into the body cavity beginning 41 mm in front of the vent. 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 subcylindrical and slightly dorsoventrally compressed. The body is not uniform in its width throughout the length. In the preserved specimen the body is 8.8 mm wide at the first annular groove and 11.7 mm at midbody in the broadest part. At 55 mm anterior to the terminus, i.e. just behind the broadest region, the body is 8.5 mm width. Thereafter the body gradually increases in width to 10.6 mm just in front of the vent. The body is 8.6 mm wide at the level of 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 1.0 mm beyond the mouth. The distance between the jaw angle and the top of the head (2.7 mm) is less than the distance between the jaw angle and the ventral surface of the lower jaw (2.9 mm). In ventral view, the anterior margin of the lower jaw is more broadly rounded than the anterior margin of the snout.

The small subcircular nostrils are slightly closer to the level of the snout tip (0.8 mm) than to the anteriormost margin of the mouth (1.1 mm) in lateral view. The nostrils are 2.0 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 circular, lateral in position and 3.8 mm apart. They are situated at a distance of 2.8 mm from the tip of the snout and 1.4 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 (0.5 mm) than to the top of the head (1.2 mm). The eyes, which are scarcely visible in life, are not visible in the preserved specimen.

We counted 25 premaxillary­maxillary (13 left, 12 right), 22 vomeropalatine, 19 dentary (9 left, 10 right) and 4 splenial teeth (including empty sockets). The vomeropalatine and splenial teeth occur in equal numbers on each side of the jaws. The teeth in all four series are generally recurved and are monocusped. They are smaller posteriorly than anteriorly. The posteriormost teeth of the premaxillary­maxillary and vomeropalatine series are not parallel, but lie closer together. 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 premaxillary­maxillary and vomeropalatine tooth rows clearly extend posterior to the choanae. When viewed anteriorly, the dentary teeth appear largest, followed by the premaxillary­maxillary and vomeropalatine teeth in decreasing order of the size. The splenials are the smallest.

The choanae are small, 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. It is separated by a groove from the gingivae. The raised narial plugs are situated far anterolaterally close to the edge of the tongue and are with encircling grooves. The posterior part of the dorsal surface of the tongue behind the narial plugs is darker than the anterior and it is marked by tiny longitudinal grooves.

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 (7.8 mm) is slightly broader than the back of the head at the jaw angle (6.5 mm) but it is less expanded than the body at the first annular groove (8.8 mm). The first collar (2.0 mm) is shorter than the second (2.5 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. There is a small transverse groove on the ventral surface just in front of the first nuchal groove. Although the nuchal and annular grooves are mostly perpendicular to the long axis of the body, the transverse groove on the second collar, the third nuchal groove and the posterior grooves of the first three 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 97 primary annuli. Secondary annular grooves occur as far forward as middorsally on the 63 rd primary annulus. They are absent on the 64 th and 65 th primary annuli but present on all subsequent primary annuli. Between the 66 th and 73 rd primary, the secondary grooves are dorsolateral in position but often not on both sides. From 74 th primary annulus onwards, they are middorsal in position, gradually increasing in length up to the terminus. The secondary grooves extend across the midline on the ventral surface from the 90 th primary annulus up to the subcircular disc surrounding the vent. The subcircular disc is 4.2 mm wide, 2.1 mm long and is interrupted by the 96 th primary and the 35 th secondary annular grooves. The rounded terminus ends in a cap that is completely demarcated by the last primary annular groove. The transverse vent is 3.3 mm wide. The vent is surrounded by ten denticles. Seven secondary grooves in front of the vent are complete. There are 35 secondary annuli.

Scales were sought at five different points along the body both dorsally and ventrally. No scales were found on the 40 th primary annulus. On the 50 th and the 56 th primary annulus the oval scales are found only on the dorsal surface in two rows. On the 90 th primary annulus, where the secondary annular grooves become complete ventrally, scales occur in two rows both on the dorsal and the ventral surfaces. Behind this annulus, on both the dorsal and ventral surfaces, scales occur in three rows in each of the annular grooves.

In life, the colour of the holotype in the anterior one third was pinkish grey, which gradually merged with the dark grey of the posterior two thirds of the body. The dorsal surface of the head was light pink and the ventral surface pinkish grey with a prominent inverted ‘V’ shaped light pink mark on the underneath of the lower jaw. The skin contains whitish glands throughout the body.

In preservation, the body is dark 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 indistinguishable in colouration from the rest of the body behind it but it has a 2 mm wide light cream coloured border. The disc surrounding the vent is whitish both in life and preservation.

Paratype: Morphometric and meristic data are given in Table 1. The paratype is very similar to the holotype. The paratype is in good condition. It measures 218 mm in length and 33 mm in circumference at midbody. There are four artefactual transverse ridges on the dorsal side, beginning c. 10 mm behind the snout. There is a 195 mm long midventral groove extending between the third nuchal groove and the vent. There is a 39 mm long midventral incision into the body cavity beginning 48 mm in front of the vent. In the preserved specimen the body is 8.5 mm wide at the first annular groove and 11.2 mm at midbody in the broadest part. At 55 mm anterior to the terminus, i.e. just behind the broadest region the body is 9.0 mm width. Thereafter the body gradually increases in width to 10.4 mm just in front of the vent. The body is 8.0 mm wide at the level of vent.

The paratype is a paler grey than the holotype. It resembles the holotype in the pattern of nuchal grooves. There are 96 complete primary annular grooves in the paratype i.e. one less than the holotype. The paratype has 27 secondary annuli with the grooves appearing most anteriorly on either side of the middorsal line of the 70 th primary annulus. The 71 st primary annulus lacks a secondary groove. Between the 72 nd and 78 th primary, the secondary grooves are dorsolateral in position but often not on both sides. From 79 th primary annulus onwards, they are middorsal in position, gradually increasing in length up to the terminus. They extend across the midline on the ventral surface from the 92 nd primary annulus up to the subcircular disc surrounding the vent. The disc is 4.0 mm wide, 2.8 mm long and is interrupted by the grooves of the 96 th primary and 27 th secondary annular grooves. The transverse vent is 3.0 mm wide and surrounded by nine denticles. Five secondary annular grooves in front of the vent are complete. The paratype has 22 premaxillary­maxillary teeth, in equal numbers on both the sides and 15 dentary teeth of which seven are on the left side and eight on the right side of the jaw. The scalation pattern resembles that of the holotype although the exact number of the primary annulus where the scaling commences differs from the latter.

Ecology and habitat: Both the holotype and paratype were collected from rotting vegetation at the base of saplings at a distance c. 5 m from a stream in an arecanut orchard. The locality is situated in the Western Ghats at approximately 80 m above sea level. The soil where the specimens were spotted was reddish­black in colour with pH 6.0, temperature 29 o C (at 30 cm depth) and 75 % canopy cover.

Comparison with congeneric species: The presence or absence of secondary annuli and grooves, the number of primary and secondary annuli, the position of secondary annuli and the external visibility of eyes are important characters used for differentiating the species of Gegeneophis ( Giri et al. 2003)  .

G. madhavai  differs from G. seshachari  in having secondary annuli and from G. ramaswamii  in having visible eyes in life. It differs from G. danieli  and G. nadkarnii  in having secondary annular grooves confined to the end of body, and from G. carnosus  , G. seshachari  , G. danieli  , G. nadkarnii  and G. krishni  in having fewer than 100 primary annuli. G. madhavai  is distinct from G. f u l l e r i in having more than 25 secondary annuli.

Externally visible eyes, fewer than 100 primary and more than 25 secondary annuli are found in other species, but not in this unique combination. The above differences are substantial to consider G. madhavai  as a new species.

Etymology: The species is named for Madhava Bhat, Madhavarao Bhide, Madhava Anantha Pai and Madhava Gadgil for supporting the first author’s research into caecilians.

TABLE 1. Some morphometric and meristic data (in mm) for the holotype (BNHS 4235) and paratype (ZSI, Calicut V / A 574) of Gegeneophis madhavai. Measurements were taken to the nearest 0.1 mm with vernier calipers. Total length and circumference were measured to the nearest 1 mm using ruler and a piece of thread.

Total length Head length 256 7.4 218 6.2
Head width at jaw angle Circumference at midbody Width of the body at 1st annular groove Width of the body at broadest region 6.5 34 8.8 11.7 5.7 33 8.5 11.2
Width of the body at the level of vent Length divided by width Length of the snout projecting beyond mouth 8.6 22 1.0 8.0 19 1.1
Distance between jaw angle and top of head 2.7 2.8

TABLE 1. Some morphometric and meristic data (in mm) for the holotype (BNHS 4235) and paratype (ZSI, Calicut V / A 574) of Gegeneophis madhavai. Measurements were taken to the nearest 0.1 mm with vernier calipers. Total length and circumference were measured to the nearest 1 mm using ruler and a piece of thread.

Total length Head length 256 7.4 218 6.2
Head width at jaw angle Circumference at midbody Width of the body at 1st annular groove Width of the body at broadest region 6.5 34 8.8 11.7 5.7 33 8.5 11.2
Width of the body at the level of vent Length divided by width Length of the snout projecting beyond mouth 8.6 22 1.0 8.0 19 1.1
Distance between jaw angle and top of head 2.7 2.8
BNHS

Bombay Natural History Society