A new short brown unpatterned moray eel (Anguilliformes, Muraenidae) from the southeast coast of India, Bay of Bengal Author Kodeeswaran, Paramasivam https://orcid.org/0000-0002-4636-3056 ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh - 226 002, India & Faculty of Fisheries Science, Kerala University of Fisheries and Ocean Studies, Kochi, Kerala - 682 506, India Author Kantharajan, Ganesan ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh - 226 002, India Author Mohapatra, Anil Estuarine Biology Regional Centre, Zoological Survey of India, Gopalpur-on-Sea, Ganjam, Odisha - 761 002, India Author Ajith Kumar, T. T. ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh - 226 002, India tt.ajith@icar.gov.in Author Kumar Sarkar, Uttam https://orcid.org/0000-0001-8166-4375 ICAR-National Bureau of Fish Genetic Resources, Lucknow, Uttar Pradesh - 226 002, India text Zoosystematics and Evolution 2023 2023-03-23 99 1 253 260 http://dx.doi.org/10.3897/zse.99.100461 journal article http://dx.doi.org/10.3897/zse.99.100461 1860-0743-1-253 A86FEFE87DFD458E9E34616C17E4D06E 3F037C3AB81851DAB88B519BE1E07A9E Gymnothorax tamilnaduensis sp. nov. Figs 2 , 3 , 4 , 5 Type material. The holotype and paratype specimens are deposited at the National Fish Repository of the ICAR-National Bureau of Fish Genetic Resources (Ministry of Agriculture and Farmers Welfare, Govt. of India). Holotype . NBFGR/MURGTAM (487 mm TL), collected from trawl landings at Mudasalodai fish landing centre, off Cuddalore coast, Bay of Bengal, 11°29'N, 79°46'E, 26 June 2022, coll. by G. Kantharajan and P. Kodeeswaran. Paratypes . Three specimens, NBFGR/ MURGTAM.2 (296 mm TL); EBRC/ ZSI/F14687 (2: 272-451 mm TL), were collected along with the holotype. Diagnosis. A new species of a short brown unpatterned moray eel with the following combination of characters: series of lines of small dark spots present on head and a single line of black spots on mid-line of body, origin of dorsal fin at middle of rictus and gill opening, anus just before mid-body, pre-anal length 45.7-47.4% TL, snout blunt and very short, 6.5-7.7 mm in HL, eye small, teeth serrated, uniserial, ethomovomerine teeth five on each side with one tooth on mid-point, vomerine with eight teeth in a series, jaw pores with white rim, anal-fin margin whitish, 3 pre-dorsal vertebrae, 56-59 pre-anal vertebrae, 139-150 total vertebrae. Figure 2. Gymnothorax tamilnaduensis sp. nov. holotype, NBFGR/MURGTAM, 487.8 mm TL, fresh colouration, collected from Mudasalodai fish landing centre, off Cuddalore, Bay of Bengal. Description (all measurements in mm). A medium-sized, moderately elongated eel with tapering body, anus just before mid-body, pre-anal length 45.7-47.4% TL, depth at gill opening 19.8-32.8 in TL, depth at anus 31.1-49.0 in TL. Head moderate, 7.8-8.2 in TL, snout blunt, and very short, 6.5-7.7 in HL, both jaws almost equal, upper jaw 2.5-3.0 in HL, lower jaw 2.4-2.8 in HL, eye small, 9.1-12.2 in HL, at middle of upper jaw, far from rictus, interorbital space 7.0-12.6 in HL. Dorsal-fin origin before gill opening, at mid-length of rictus and gill opening, pre-dorsal length 9.3-11.0 in TL, anal fin starts just after anus, gill opening a minute diagonal slit, 8.0-11.3 in HL. Teeth serrated, uniserial; five pointed ethomovomerine teeth on each side, one tooth on mid-point, three median ethomovomerine teeth, middle tooth larger than other two, maxillary teeth uniserial, 12-13 on each side, uniserial vomerine with eight teeth; lower jaw teeth uniserial, 16-17 teeth on each side, three anterior teeth enlarged (Fig. 3 ). Head pores moderate-sized, three supraorbital pores, four infraorbital pores, six mandibular pores before rictus, cephalic pores in white rims. Branchial pores two behind the dorsal-fin origin (Fig. 4 ). Three pre-dorsal vertebrae, 56-59 pre-anal vertebrae, 139-150 total vertebrae. Figure 3. Dentition pattern on upper jaw and lower jaw of Gymnothorax tamilnaduensis sp. nov (holotype). Figure 4. Lateral view of head and cephalic pores of Gymnothorax tamilnaduensis sp. nov. (holotype, NBFGR/MURGTAM). Supraorbital pores (SO) - Blue closed dots, Infraorbital pores (IO) - Green, Mandibular pores (M) - Red, Branchial pores (B) - Black; DFO - dorsal-fin origin, PN - Posterior nostril, AN - Anterior nostril, GO - Gill opening. Table 1. Meristic and morphometric characters of Gymnothorax tamilnaduensis sp. nov. compared with other short brown unpatterned moray described from Indian waters.

-	Gymnothorax tamilnaduensis sp. nov.				G. andamanensis	G. mishrai	G. odishi
	Holotype	Paratype	Paratype	Paratype	n = 2	n = 1	n = 11
Total length (mm)	487	451	296	272	325-464	324	420-700
In TL
Pre-anal length	2.2	2.1	2.1	2.2	2.1-2.2	2.0	1.9-2.1
Predorsal length	11.0	9.3	10.9	9.5	9.9-10.8	-	8.4-10.8
Head length	8.2	7.8	8.1	8.2	8.1	6.9	6.7-7.6
Depth at gill opening	19.8	22.1	28.8	32.8	15-17.1	19.0	11.5-18.4
Depth at anus	31.1	31.8	38.7	49.0	16-19.1	24.9	17.3-24.0
In HL
Snout length	6.5	6.7	7.4	6.6	4.4	6.5	4.3-5.4
Eye diameter	10.3	12.2	9.1	11.6	6.7-7.6	20.2	8.6-10.8
Inter-orbital space	7.0	8.2	12.6	11.1	6.7-8.8	8.7	6.0-7.9
Jaw length	2.5	2.6	2.6	3.0	2.2-2.4	2.9	2.2-2.8
Vertebrae
Pre-dorsal vertebrae	3	3	3	3	3	9	4
Pre-anal vertebrae	59	56	56	57	57	59	56-58
Total vertebrae	150	143	139	140	135-136	134	134-138

Counts and measurements of the holotype in mm: TL 487.8, pre-anal length 223.1, tail length 260.7, trunk length 155, pre-dorsal length 44.4, head length 59.6, depth at anus 15.7, width at anus 12.3, snout length 9.2, eye diameter 5.7, upper jaw length 23.9, interorbital width 8.5, gill opening 6.8. Vertebral formula 3-59-150. Colouration. In fresh condition, body uniform chocolate brown, head with numerous line marks, ventral-most portion of lower body pale, dorsal fin brown, dorsal-fin margin black, anal-fin margin whitish, head pores with white rim, series of small dark spots forming several lines on head and a single line of black spot-on mid-line of body (Fig. 2 ). After preservation, body tanned, series of small dark spot lines remain the same in the head and body (Fig. 5 ). Figure 5. Gymnothorax tamilnaduensis sp. nov. holotype, NBFGR/MURGTAM, 487.8 mm TL preserved colouration. Distribution. Indian Ocean: off Cuddalore Coast, Bay of Bengal, southeast coast of India. The species were collected at a depth of about 25-30 metres. Etymology. The species is named " tamilnaduensis " with reference to the state Tamil Nadu from where it was collected. Remarks. The brown unpatterned groups of morays were divided into two groups by Boehlke (1997 , 2000 ): the long brown unpatterned morays (> 150 vertebrae) and the short brown unpatterned morays (<150 vertebrae). The species described herein comes under the short brown unpatterned moray. From Indian waters, only three species of short brown unpatterned morays have been described to date ( Mohapatra et al. 2019 ). All three short brown unpatterned morays reported from India have smooth teeth, and the new species clearly differs from all three species in having serrated teeth. The new species differs from all the Indian water short brown morays by having jaw pores with white rim (vs. black in G. andamanensis , brown in G. mishrai and dark in G. odishi ); having more total vertebrae (139-150 vs. 135-136 in G. andamanensis , 134 in G. mishrai and 133-138 in G. odishi ); smaller snout (6.5-7.4 in HL vs. 4.4 in G. andamanensis , 6.5 in G. mishrai , 4.3-5.4 in G. odishi ); having a distinct series of lines of small dark spots present on head and a single line of black spot on the mid-line of the body (vs. absent in all the other species). The new species shares serrate teeth with Gymnothorax atolli (Pietschmann, 1935), G. australicola Lavenberg 1992, G. panamensis (Steindachner, 1876) and G. pindae Smith 1962, but the new species differs from the species mentioned above by having more total vertebrae (139-150 vs. 127-133 in G. atolli , 122-137 in G. panamensis and 110-124 in G. pindae ), fewer predorsal vertebrae (3 vs. 4-6 in G. atolli , 5-6 in G. australicola , 8-12 in G. panamensis and 5-7 in G. pindae ) and uniserial maxillary teeth (vs. biserial in G. atolli , G. australicola and G. panamensis ). Further, the new species differs from the other unpatterned morays, such as Gymnothorax herrei Beebe & Tee-Van, 1933, G. kontodontos Boehlke , 2000, G. microstictus Boehlke , 2000 and G. pseudoherrei Boehlke , 2000 by having serrate teeth (vs. smooth in all the remaining species); more total vertebrae (139-150 vs. 108-122 in G. herrei , 126-135 in G. kontodontos , 113-121 in G. microstictus , 110-118 in G. pseudoherrei ); more pre-anal vertebrae (56-59 vs. 45-50 in G. herrei , 40-43 in G. kontodontos , 40-44 in G. microstictus , 44-50 in G. pseudoherrei ) (Table 2 ). Table 2. Comparative characters from short brown unpatterned Gymnothorax (data obtained from Boehlke (2000) and specimens examined from India).

-	G. tamilnaduensis sp. nov.	G. andamanensis	G. atolli	G. australicola	G. herrei	G. kontodontos	G. microstictus	G. mishrai	G. odishi	G. panamensis	G. pindae	G. pseudoherrei
Branchial pores	2	2	1	1	1	2	2	2	2	2	2	2
Pre-dorsal vert.	3	3	4-6	5-6	7-11	7-9	4-5	9	4	8-12	5-7	5-9
Pre-anal vert.	56-59	57	51-54	52-56	45-50	40-43	40-44	59	55-58	50-55	42-46	44-50
Total vert.	139-150	135-136	127-133	141-146	108-122	126-135	113-121	134	133-138	122-137	110-124	110-118
Jaw pores	White rim	Black rim	White rim	White rim	Pale rim	Pale rim	Brown rim	Brown rim	Dark rim	White rim	Brown rim	Brown rim
Median EV teeth	0-3	3	2	2	2-3	2	2	3	3	2	2	2
Inner EV teeth	0	3	8-14	7-12	8-15	9-13	0-7	0	0	9-12	0-10	8-21
MX teeth	Uniserial	Biserial	Biserial	Biserial	Biserial	2-3 series	1-2 series	Uniserial	Uniserial	Biserial	Uniserial	Biserial
DFO/GO	Before	Before	Before	Before	Behind	Behind	Before	Before	Before	Behind	Before	Before
VM teeth	Uniserial	Uniserial	Uniserial	Uniserial	Uniserial	2-3 series	Uniserial	Uniserial	Uniserial	Irregular	Staggered	Staggered
Teeth edge	Serrate	Smooth	Serrate	Serrate	Smooth	Smooth	Smooth	Smooth	Smooth	Serrate	Serrate	Smooth

Molecular analysis. Based on the 16s rRNA gene sequences, the new species exhibits 8.0% genetic divergence with G. reticularis sequences in the Kimura 2 parameter. Further, the new species exhibits 10.1% genetic divergence with G. sagmacephalus , followed by G. albimarginatus by 11.2%-12.1%, G. castaneus (11.9%) and G. pictus (12.6%). The Maximum Likelihood tree (Fig. 6 ) shows the new species forms a strongly distinct clade from the congeners with a high bootstrap value supporting the status as a new species. Figure 6. The Maximum Likelihood tree of the genus Gymnothorax plotted with a model of HKY+G+I with 1000 bootstrap replicates, based on 16s rRNA sequences (500 bp). Each node represents branch support values.