Ichthyophis catlocensis, Geissler & Poyarkov & Grismer & Nguyen & An & Neang & Kupfer & Ziegler & Böhme & Müller, 2015

Geissler, Peter, Poyarkov, Nikolay A., Grismer, Lee, Nguyen, Truong Q., An, Hang T., Neang, Thy, Kupfer, Alexander, Ziegler, Thomas, Böhme, Wolfgang & Müller, Hendrik, 2015, New Ichthyophis species from Indochina (Gymnophiona, Ichthyophiidae): 1. The unstriped forms with descriptions of three new species and the redescriptions of I. acuminatus Taylor, 1960, I. youngorum Taylor, 1960 and I. laosensis Taylor, 1969, Organisms Diversity & Evolution (New York, N. Y.) 15 (1), pp. 143-174 : 160-162

Ichthyophis catlocensis sp. nov.

Holotype Metamorphosed female ( ZFMK 88976 , Fig. 9 ), collected on 8 April 2009 by P. Geissler in Sui Lan stream bed near Phuoc Son Ranger Station (11° 37′ 22.5″ N 107° 17′ 57.2″ E; elevation, 135 m), Cat Loc area, Cat Tien National Park, Lam Dong Province, in southern Vietnam (see Fig. 1).

Diagnosis A species of Ichthyophis without a lateral yellow stripe; snout blunt and rounded ( SP / HL =0.07); TN/ ET =4.5; premaxillary and maxillary teeth 44, vomeropalatine teeth 51, dentary teeth 27, inner mandibular teeth 16; inner mandibular tooth row shorter than dentary row; tail ending in a large blunt cap; total annuli 342 (dorsal count), encircling venter by forming an angle pointing tailwards, five interupted by cloacal disc, five posterior to cloacal disc; cloacal disc elliptic in shape; 110 vertebrae; scales present solely on posterior half of body, in one row per annulus (dorsolaterally). The new species differs from all other known unstriped congeners in the following characters: from I. acuminatus by the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 2.4–3.1); from I. billitonensis by more inner mandibular teeth (16 vs. 2); from I. bombayensis by the absence of scales in the anterior half of body; from I. cardamomensis sp. nov. by the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 2.8–3.2); from I. chaloensis sp. nov. by a larger eye size ( HL / ED =14.6 vs. 31.3) and a smaller snout projection ( SP / HL =0.07 vs. 0.14); from I. dulitensis by the absence of scales in the anterior half of body; from I. glandulosus in having more annuli (342 vs. 273–286); from I. javanicus by the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 2.3); from I. lakimi by a more elongated snout, which affects the following characters: the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 1.9), and the snout length being longer with respect to head length ( HL / ES =2.0 in I. catlocensis sp. nov. vs. 1.6 in I. lakimi ); from I. laosensis by the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 2.7); from I. larutensis by the presence of inner mandibular teeth; from I. monochrous by the absence of scales on the anterior half of body and a higher count of annuli (342 vs. 247); from I. orthoplicatus by a higher count of annuli (342 vs. 205–291); from I. sikkimensis by more annuli (342 vs. 276–292); from I. singaporensis by the absence of scales on the anterior half of body; from I. sumatranus by the absence of scales on the anterior half of body; from I. weberi by the presence of inner mandibular teeth; from I. youngorum by the tentacle being much closer to the eye than to naris ( TN / ET =4.5 vs. 2.0).

Description of holotype Selected morphological and meristic data are given in Table 4. Condition of the preserved specimen: incisions in both corners of mouth in order to open the mouth; one 10 mm long ventral incision in the first third of body; second ventral incision from about 8 mm behind the latter, running down towards vent disc; few scale pockets opened dorsolaterally; paravertebral skin somewhat parched during fixation, resulting in a brownish coloration of the affected areas.

Head ( Fig. 9 ) elongated and flattened dorsoventrally, in dorsal view as broad as collar region, slightly narrowing between corner of mouth and tentacles; snout bluntly rounded anterior to tentacles; in lateral view, head barely tapered between collar region and nares, anterior to nares snout dropping down in a blunt arc; lips straight edged, corner of mouth closer to throat than to top of head; mouth almost terminal, snout barely projecting; in ventral view, gular region flattened, with a distinct median depressed groove, starting between tentacles and fading on collar region; eyes clearly visible through unpigmented skin, rounded, lens forming a grey, round central disc, slightly elevated above adjacent skin; in lateral view, eyes in a median position between top of head and upper lip; tentacle aperture 4.5 times closer to eye than to naris, close to upper lip, smaller than eyes, about the size of the naris; tentacular aperture elevated from surrounding skin, visible in lateral, dorsal and ventral view; in preservative, tentacles protrude slightly from the tentacular apperture; nares oval in shape, closer to upper lip than to top of head, neither visible in dorsal nor in ventral view; teeth ( Fig. 5b ) small, recurved and bicuspid, main cusp slightly longer than accessory cusp; 44 teeth in premaxillary-maxillary, 51 in vomeropalatine, 27 in dentary, and 16 in inner mandibular row; teeth in premaxillary-maxillary row as large as teeth in vomeropalatine row, but smaller than teeth in dentary as well as in inner mandibular row; length of premaxillary-maxillary tooth row shorter than length of vomeropalatine row; length of inner mandibular tooth row about half of dentary row; palate slightly arced; choanae oval, elongat- ed, posterior to tentacles; tongue semi-elliptic with a median, triangular depression on its posterior half; collar region barely distinct from head or adjacent body; collar grooves weak; first four annular grooves not encircling venter; total annuli 342/340 (dorsal count/ventral count); vertebrae 110; grooves encircling venter forming an angle pointing towards tail in the anterior 140 mm of body length, on the last 30 mm anterior to cloacal disc grooves cross venter in a straight line; slight depression along midline of belly present on the anterior 140 mm of trunk; on dorsum, grooves cross in an even S shape, slightly curving posteromedially along the vertebral line; longitudinal cloacal slit situated in an elliptic cloacal disc, interrupting five annuli; cloaca surrounded by 7/7 (right /left) denticulations ( Fig. 7b ); tail bearing five annuli, annular grooves fading on ventral side; tail terminating in a large blunt tail cap; scales only present in scale pockets in posterior half of body; scales minute to small, oval in shape, present in one row per scale pocket (counted dorsolaterally).

Coloration In preservative: light pinkish grey all over body and tail, slightly lighter on venter; cloacal disc white; and eyes, tentacles, and nares encircled by a narrow whitish grey margin (see Fig. 9 ). In life: dark grey all over body, somewhat lighter on venter; annular grooves blackish; and margins of tentacles, eyes, and nares whitish (see Fig. 10 ).

Natural history The type specimen was found at 2:00 p.m. on 8 April 2009, hiding under a stone (30 cm in diameter) on a sunlit sand bar at the edge of the small forest rivulet Sui Lan. Substrate temperature was 27 °C. The steep slopes of the rivulet valley were dominated by highly damaged secondary bamboo forest with numerous bushes of rattan palms ( Calamus sp. ) and occasional large trees ( Dipterocarpus sp. ). The species occurs sympatrically with I. nguyenorum ; larvae of this striped Ichthyophis species were found in the same rivulet. Other sympatric species of amphibians include Ingerophrynus galeatus , Odorrana cf. banaorum , Rhacophorus rhodopus , Limnonectes poilani , Theloderma bambusicola , and Polypedates leucomystax .

Etymology We name this new species after its type locality, the Cat Loc area of the Cat Tien National Park. This is to underline the importance of this National Park for conservating the unique biodiversity of the lowland forests in southern Vietnam.

Figures

Fig. 9 Holotype (ZFMK 88976) of Ichthyophis catlocensis sp. nov. in preservative (TL, 183.5 mm). Photographs by PG

Fig. 5 a–f Jaws of the holotype of (depicted characters are also present in the respectively investigated paratype specimens): a Ichthyophis cardamomensis sp. nov. (LSUHC 9335), b Ichthyophis catlocensis sp. nov. (ZFMK 88976), c Ichthyophis chaloensis sp. nov. (IEBR A.2011.16), d Ichthyophis laosensis (MNHN 1928.95), e Ichthyophis acuminatus (AMNH A20875), and f Ichthyophis youngorum (FMNH 189250). Drawings by PG

Fig. 7 a–f Holotype (LSUHC 9335) of Ichthyophis cardamomensis sp. nov. in preservative (TL, 183.0 mm). Photographs by PG

Fig. 10 a, b Holotype (ZFMK 88976) of Ichthyophis catlocensis sp. nov. in life (TL, 183.5 mm) from Cat Loc, Cat Tien National Park, Lam Dong Province, southern Vietnam. a General view. Photograph by PG; b close up of the head. Photograph by E.A. Galoyan