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Mohanty, Swarup Ranjan, Behera, Rajesh Kumar, Patro, Shesdev, Mohapatra, Anil (2023): A new species of cirri-bearing eel of the genus Cirrhimuraena (Anguilliformes: Ophichthidae) from the coastal Bay of Bengal, India. Zootaxa 5315 (6): 575-583, DOI: 10.11646/zootaxa.5315.6.5, URL: http://dx.doi.org/10.11646/zootaxa.5315.6.5

Cirrhimuraena odishaensis sp. nov. Proposed commom name: Odisha fringe-lip eel (Figs. 2–4; Table 1). urn:lsid:zoobank.org:act: 5BB58FDF-C693-4432-891D-4FBA52172932 Holotype. EBRC /ZSI/F 11811 (395 mm TL), Palur canal (19.47068889°, 85.14005833°), Odisha, India, 2 Aug. 2021. Paratype. EBRC /ZSI/F 14713 (320 mm TL), Talasari Fish Landing Centre (21.60361111°, 87.46027778°), Odisha, India, 2 Mar. 2022. Diagnosis. Dorsal fin origin directly above midpoint of pectoral fin; single row of mandibular teeth; 1–4 rows of vomerine teeth; 13 total cirri on upper jaw (8 before anterior nostril and 5 between nostrils); and vertebral count of pre-dorsal 10, pre-anal 46–47, and total 160–162; small pectoral fin (4.0– 4.9 in HL). Description. Body elongated, with depth at gill opening of 58.1–62.7 in total length (TL) and depth at anus of 52.7–62.7 in TL. Tail longer than head and trunk, 1.5 in TL. Anus present before midbody and pre-anal (head and trunk), 3.0– 3.1 in TL. Dorsal fin originates above midpoint of pectoral fin. Pre-dorsal length 9.4–10.1 in TL. Head moderate, length 11.0– 11.5 in TL. Eye small, located closer to snout tip than rictus, diameter 18.0– 18.6 in head length (HL). Snout pointed at tip, length 6.0– 6.8 in HL. Space between eye slightly convex and 15.6–18.6 in HL. Length of upper jaw is greater than lower jaw, upper jaw with small tubular anterior nostrils present near tip of snout and flap-like posterior nostrils present slightly anterior to orbit on maxilla, edge of upper lip with 5 small cirri in between anterior and posterior nostrils, and 8 small cirri behind posterior nostril. Lower jaw lacks cirri and tip of jaw reaching in front of anterior nostrils. Pectoral fin lanceolated, originates in front of gill opening, length 43.9–53.3 in TL and 4.0– 4.7 in HL, and pectoral-fin base length 12.0– 15.5 in HL. Gill opens at latero-ventral side of body; depth 9.0– 9.6 in HL. Dorsal fin with 298–303 rays, anal fin with 197–198 rays, and pectoral fin with 9 rays. Pre-dorsal vertebrae 10, pre-anal vertebrae 46–47, and total vertebral 160–162. Head pores: supraorbital 4; infra-orbital 5; mandibular 3; temporal 1; supra-temporal 3. Lateral line pores before gill opening 11; before dorsal-fin origin 12; before anus 49, and total lateral-line pores 137+ (not clear towards tail tip). Tooth band formed by tiny, club-shaped, pointed teeth, closely grouped together and slightly curved at tip. Prevomer with patch of 14 teeth. Vomerine teeth arranged in 3–6 rows, extending near to posterior maxillary tip. Maxillary teeth in 3–7 rows of small, conical, and club-shaped teeth in unique pattern as shown in Figure 3. Mandibular teeth in one row of teeth on each side. Colour. Dorsal side of body is pale brown and ventral side of body is milky white. Dorsal, ventral, and pectoral fins are white. Distribution. The species was collected from the Palur canal, very near the Chilika lagoon, and from a creek close to the Subarnarekha Estuary (Talasari fish landing centre), Odisha, India. Both specimens were caught from channels connecting estuaries to the sea and are not very frequent. It may be possibly caught during the migration. Etymology. The species is named Cirrhimuraena odishaensis based on the collection site “ Odisha ” — a state of India. The common name of the species is proposed as “ Odisha fringe-lip eel.” Comparative materials. Cirrhimuraena indica (Holotype)— EBRC /ZSI/F 11811 (232 mm TL), Paradeep fishing harbour, Odisha, India, 10 May 2019. Paratypes EBRC /ZSI/F 12062, 1 ex. (345 mm TL), Non-type EBRC/ ZSI/F 12063 (400 mm TL), EBRC /ZSI/F 12064, 1 ex. (512 mm TL), EBRC /ZSI/F 12065, 1 ex. (353 mm TL) and EBRC /ZSI/F 12066, 1 ex. (380 mm TL), Paradeep fishing harbour, Odisha, India, 25 October 2019, EBRC/ZSI/F 12067 (1 ex, 401 mm TL) and MARC /ZSI/F 7778 (1 ex, 381 mm TL), Petuaghat Fishing Port, West Bengal, India, 16 Jan. 2020. Cirrhimuraena playfairii — EBRC /ZSI/F12060, 1 ex. (452 mm TL), Paradeep fishing harbour, Odisha coast, India, 25 October 2019, EBRC /ZSI/F1576, 1 ex. (502 mm TL), Upapara, near Kakinada (Godavari Estuary), Andhra Pradesh, India, 18 Mar. 1995., Published as part of Mohanty, Swarup Ranjan, Behera, Rajesh Kumar, Patro, Shesdev & Mohapatra, Anil, 2023, A new species of cirri-bearing eel of the genus Cirrhimuraena (Anguilliformes: Ophichthidae) from the coastal Bay of Bengal, India, pp. 575-583 in Zootaxa 5315 (6) on pages 576-580, DOI: 10.11646/zootaxa.5315.6.5, http://zenodo.org/record/8142547

Gymnothorax poikilospilus sp. nov. is described based on two specimens collected from Penghu Islands, western Taiwan. It is a medium-sized brown moray that body covered with several rows of inconspicuous large dark brown patches on the back of body and dorsal fin. It has slightly elongated and arched jaws similar to the common characteristic of the genus Enchelycore Kaup, but the dentition supports it belongs to typical morays of the genus Gymnothorax Bloch. The new species can be distinguished from other similar Indo-Pacific brown morays by the combination of dentition, vertebral formula, and morphometric measurements. Molecular analyses based on 612 bp of mitochondrial COI gene also support it as a distinct species.

An additional description of the Misol snake eel Yirrkala misolensis (Günther, 1872) is reported on the basis of 9 specimens collected from Dong-gang and Ke-tzu-liao, southwestern Taiwan. The species was previously reported from Indonesia and Australia and then extends northward to Taiwan and Japan, and was lacking adequate characterization on morphology. A detail description, fine condition of fresh photographs and 4 partial CO1 sequences are provided for the first time.

Two new species of the elongate snake eel genus Bascanichthys are described from the northwestern Pacific. Bascanichthys kabeyawan sp. nov. is described based on a single specimen collected from estuary of southern Taiwan. It is characterized by having head 4.6% TL; tail 52.3% TL; body depth at gill opening 1.1% TL; predorsal-fin length 58.4% HL; snout length 10.9% HL; body bicolored, head without bands; lateral-line pores anterior to anus 104; vertebral formula 4-103-224. Bascanichthys ryukyuensis sp. nov. is described based on two specimens collected from the shallow water of Okinawa-jima Island, Ryukyu Islands of southern Japan. It is characterized by having head 3.7–4.3% TL; tail 43.3–44.2% TL; predorsal-fin length 40.7–45.4% HL; snout length 11.3–13.1% HL; body pale brown, head without distinct dark bands after preservation; lateral-line pores anterior to anus 114–118; total vertebrae 207–216, mean vertebral formula 2-116-212; and dorsal-fin origin before middle of head.

FAMILY Moringuidae Moringua raitaborua (Hamilton, 1822); Native; Purple Spaghetti-Eel; Found in rivers and watersheds of Visayas Islands; Kottelat 2013; NE

FAMILY Anguillidae Anguilla borneensis Popta, 1924; Native; Borneo Eel; Found in river basins of Southern Mindanao Island; Kottelat 2013, Shirotori et al. 2016; VU Anguilla bicolor McClelland, 1844; Native; Bicolor Eel; Found in wetlands and river basins across the Philippines. Most likely to be the subspecies Anguilla bicolor pacifica; AUM 9819, NMST-P 72123-24; Kottelat 2013, Aoyama et al. 2015, Shirotori et al. 2016; NT Anguilla celebesensis Kaup, 1856; Native; Celebes Longfin Eel; Found in river basins of Luzon, Visayas and Mindanao Island groups; Kottelat 2013, Aoyama et al. 2015, Shirotori et al. 2016; DD Anguilla interioris Whitley, 1938; Native; Highlands Long-Finned Eel; Found in river basins Visayas and Mindanao Island groups; Kottelat 2013, Shirotori et al., 2016; DD Anguilla japonica Temminck & Schlegel, 1846; Native; Japanese Eel; Found in northern and eastern river basins of Luzon, Visayas and Mindanao Island groups; Kottelat 2013, Shirotori et al. 2016; EN Anguilla luzonensis Watanabe, Aoyama & Tsukamoto, 2009; Native; Luzon Eel, Philippine Mottled Eel; Found mainly in river basins of Northern Luzon, but also found in Visayas and Mindanao Island groups; NSMT-P 90000-28; Watanabe, Aoyama, Tsukamoto, 2009, Kottelat 2013, Shirotori et al. 2016, Canon et al. 2021; VU Anguilla marmorata Quoy & Gaimard, 1824; Native; Giant Mottled Eel, Indo-Pacific Eel; Found in watersheds and river basins across the Philippines; USNM 318419; Jamandre et al. 2007, Kottelat 2013, Shirotori et al. 2016, Canon et al. 2021; LC, Published as part of Jamandre, Brian Wade, 2023, Freshwater fishes of the Philippines: a provisional checklist, pp. 151-181 in Zootaxa 5301 (2) on page 159, DOI: 10.11646/zootaxa.5301.2.1, http://zenodo.org/record/8030274, {"references":["Kottelat, M. (2013) The fishes of the inland waters of Southeast Asia: A catalogue and core bibliography of the fishes known to occur in freshwaters, mangroves and estuaries. Raffles Bulletin of Zoology, Supplement No. 27, 1 - 663.","Shirotori, F., Ishikawa, T., Tanaka, C., Aoyama, J., Shinoda, A., Yambot, A. V. & Yoshinaga, T. (2016) Species composition of anguillid glass eels recruited at southern Mindanao Island, the Philippines. Fisheries Science, 82, 915 - 922. https: // doi. org / 10.1007 / s 12562 - 016 - 1030 - 8","Aoyama, J., Yoshinaga, T., Shinoda, A., Shirotori, F., Yambot, A. V. & Han, Y. - S. (2015) Seasonal changes in species composition of glass eels of the genus Anguilla (Teleostei: Anguillidae) recruiting to the Cagayan River, Luzon Island, the Philippines. Pacific Science, 69 (2), 263 - 270. https: // doi. org / 10.2984 / 69.2.8","Watanabe, S., Aoyama, J., Tsukamoto, K. (2009) A new species of freshwater eel Anguilla luzonensis (Teleostei: Anguillidae) from Luzon Island of the Philippines. Fisheries Science, 75, 387 - 392. https: // doi. org / 10.1007 / s 12562 - 009 - 0087 - z","Canon, K. L., Nieves, P. M., Mendoza Jr., A. B., Nolial, J. C. C., Celestial, N. C., Mediario, R. O., Bradecina, R. G., Avila, T. N. & Kubota, S. (2021) Occurrence of Anguilla luzonensis in the tributaries along the Lagonoy Gulf, Philippines. Journal of Fisheries Science, 3 (1), 8 - 16. https: // doi. org / 10.30564 / jfsr. v 3 i 1.3010","Jamandre, B. W., Shen, K. N., Yambot, A. V. & Tzeng, W. N. (2007) Molecular phylogeny of Philippine freshwater eels Anguilla spp. (Actinopterygi: Anguilliformes: Anguillidae) inferred from mitrochondrial DNA. Raffles Bulletin of Zoology, 14, 51 - 59."]}

FAMILY Ophichthidae Lamnostoma kampeni (Weber & de Beaufort, 1916); Native; Freshwater Snake-Eel; Found in river basins of Luzon, Visayas and Mindanao Island groups; Herre 1953; NE Lamnostoma mindora (Jordan & Richardson, 1908); Native; Mindoro Snake-Eel; Found in river basins of Luzon and Mindoro Island groups; CAS-SU 20209; Herre 1953, Kottelat 2013; NE Lamnostoma orientale (McClelland, 1844); Native; Oriental Worm-Eel; Found in river basins of Palawan, Visayas and Mindanao Island Groups; USNM 134959; Kottelat 2013; LC Lamnostoma taylori (Herre, 1923); Native; Found in rivers of Luzon and Visayas islands; Kottelat 2013; NE Muraenichthys thompsoni Jordan & Richardson, 1908; Native; Thompson’s Snake Eel; Found in rivers of Luzon, Visayas and Mindanao Islands; Herre, 1923, Kottelat 2013; NE Ophichthus polyophthalmus Bleeker, 1864; Native; Many-Eyed Snake Eel; Found in rivers and watersheds Visayas Islands; Herre 1953, Kottelat 2013; NE Pisodonophis boro (Hamilton, 1822); Native; Rice-Paddy Eel; Found in river basins of Visayas and Mindanao Island groups; CAS-SU 26831, CAS-SU 26837; Herre 1953, Kottelat 2013; LC Pisodonophis cancrivorus (Richardson, 1848); Native; Longfin Snake-Eel; Found in watersheds of Luzon, Visayas and Mindanao Island groups; CAS-SU 38873; Herre 1953, Kottelat 2013; NE Yirrkala kaupii (Bleeker, 1858); Native; Worm Eel; Found in watersheds of Luzon, Visayas and Mindanao Island groups; Herre 1953; NE, Published as part of Jamandre, Brian Wade, 2023, Freshwater fishes of the Philippines: a provisional checklist, pp. 151-181 in Zootaxa 5301 (2) on page 160, DOI: 10.11646/zootaxa.5301.2.1, http://zenodo.org/record/8030274, {"references":["Herre, A. W. C. T. (1953) Check list of Philippine fishes. Fish and Wildlife Service Research Report, 20, 293 - 295.","Kottelat, M. (2013) The fishes of the inland waters of Southeast Asia: A catalogue and core bibliography of the fishes known to occur in freshwaters, mangroves and estuaries. Raffles Bulletin of Zoology, Supplement No. 27, 1 - 663."]}

Jamandre, Brian Wade (2023): Freshwater fishes of the Philippines: a provisional checklist. Zootaxa 5301 (2): 151-181, DOI: 10.11646/zootaxa.5301.2.1, URL: http://dx.doi.org/10.11646/zootaxa.5301.2.1

Conger melanopterus, new species New English Name: Indian Black-fin Conger (Figures 1–5; Tables 1–3) Holotype: NBFGR /CONCMEL, (569 mm TL, spent female) collected from deep-sea trawl, Colachel fishing harbour (8°10′21.92″N, 77°15′2.98″E), Southwest coast of India, Indian Ocean, Deepa Dhas, D. S., 08 July 2021. Diagnosis. A moderate sized dark-coloured eel of the genus Conger, distinguished from its congeners by having the following combination of characters: dorsal-fin origin behind the pectoral-fin tip; larger head, 18.5% TL; longer predorsal length 24.0% TL; relatively shorter trunk, 52.4% PAL; smaller eye, 12.9% HL; trunk length is 1.1 times in head length; vomer with seven uniserial teeth at posterior end; body fully blackish to dark brown; pectoral fin much darker than body; cephalic pores with whitish rims; SO pores 3; first two pores located at snout tip; small adnasal pore, which is positioned adjacent to third SO pore; IO pores 6, 5 before rictus and 1 behind rictus; pectoral rays 19; total vertebrae 141+. Description. Morphometric measurements in proportion of total length: head length 5.4 in TL; preanal length 2.5; predorsal length 4.2; trunk length 4.7; tail length 1.7; depth at gill opening 15.6. Measurements in proportion of head length: snout length 4.0 in HL; eye diameter 7.7; interorbital width 6.1; upper jaw 2.8; gill opening width 6.8; interbranchial width 3.7; pectoral fin 3.3. Meristic data and morphometric proportion of % TL, PAL and HL are provided in Table 1. Moderately elongate eel with anus positioned before mid-length, preanal length 40.6% TL. Relatively slender tail with flexible caudal fin. DFO behind pectoral-fin tip, predorsal length 24.0% of TL and continuous with caudal and anal fins. Snout moderate, fleshy part projecting slightly beyond intermaxillary tooth patch. Head relatively large, 18.5% TL. Anterior nostril rather large; posterior nostril moderate pore in front of eye. Both jaws almost equal in length with well-developed flanges. Tongue large and broad, anterior half free from mouth floor, with pointed tip. Head pores small, positioned on head instead of flanges. SO pores 3; first two pores located at snout tip; small adnasal pore, which is positioned adjacent to third SO pore. IO pores 6; 5 before rictus and 1 behind rictus. ST canal with 1 pore; preoperculo-mandibular pores 9, 6 before rictus and 3 behind rictus (Fig. 3). Lateral line almost complete, pores inconspicuous; 5 prepectoral pores, 13 predorsal pores, 34 preanal pores and 138 total pores. 14 predorsal vertebrae; 36 preanal vertebrae; 141+ total vertebrae; 19 pectoral rays. Teeth small, pointed or blunt and acute. Rounded intermaxillary tooth patch with 4 transverse rows, not well separated from maxillary and vomerine teeth. Maxillary and dentary teeth in two rows, those of outer row pointed, those of inner row blunt and reaching more than half length of outer maxillary rows. Vomerine teeth pointed or blunt, forming a long patch, 3 or 4 transverse rows in the anterior portion, followed by seven uniserial teeth posteriorly (Fig. 4). Morphometric data of holotype (in mm): TL 569, HL 105.4, depth at gill opening 36.4, depth at anus 35.7, predorsal length 136.7, preanal length 231.2, trunk length 121.0, tail length 333.5, snout length 26.4, eye diameter 13.6, interorbital width 17.2, upper jaw length 37.2, gill opening width 15.5, interbranchial width 28.3, pectoral fin length 32.4. Colouration. For general appearance see Figs. 1 & 2. Body uniformly blackish to dark brown (not much brown), median fin bases and distal margins also black (Figs. 1 & 2A). Ventral surface of head blackish; anterior nostril pale pinkish to brown; rims of cephalic pores milky white (Figs. 2B, 2C). Inner surface of flanges whitish; tongue white to pale brown with numerous melanophores on side margins and lower surface, but not at the tip. Pectoral fin completely black, much darker than body. In preservative: body remains the same, but darker than when fresh. Etymology. The species name “ melanopterus ” derived from two Greek words melano (μελανός) = black and pterus (πτερόν) = winged, denotes black pectoral fin. Distribution. Southwest coast of India, Arabian Sea, Indian Ocean. The species was collected at a depth of 300 m along the EEZ of Indian Waters in the Western Indian Ocean. Molecular analysis. The K2P genetic analysis reveals that new the species is closely related to C. verreauxi from Australian waters with a divergence of 5.7%. Further, the genetic divergence between the new species and C. macrocephalus from Indonesian and Taiwan waters was 5.9%. The new species differs from the species commonly treated as Conger wilsoni (Bloch & Schneider, 1801) in Australian waters and Conger myriaster (Brevoort, 1856) from Taiwan waters with 6.4% and 6.8% divergence respectively. The new species shows a maximum genetic divergence between Conger triporiceps Kanazawa, 1958 with 22.7%, followed C. cinereus with 22.0%, Conger oceanicus (Mitchill, 1818) with 15.2%, and Conger orbignianus Valenciennes 1837 with 15.1% and Conger conger (Linnaeus, 1758) with 10.9% (Table 2). In the maximum likelihood tree (Fig. 6), C. melanopterus forms a distinct lineage sister to known congeners with high bootstrap values supporting the status as a new species. Comparison. Conger melanopterus differs from all other congeners but shares few characters with C. macrocephalus such as larger head 18.5% (vs. 15.4–21.0% in C. macrocephalus) and maxillary teeth with 2 rows. It differs from C. macrocephalus in having more total vertebrae (141+ vs. 132–139), a larger gill opening length (14.7% HL vs. 10.7–13.1% HL), trunk length 1.1 times in head length (vs. 1.2–1.6), smaller eye (12.9% HL vs. 13.7–18.7%), shorter tail (58.6% TL vs. 59.3–62.2% TL), more pectoral rays (19 vs. 17), pectoral fin completely dark (vs. pale or with large black patch), body completely dark including median fins and margin (vs. pale greyish to brown, median fins whitish with black margin) and vomerine teeth forming seven uniserial teeth in posterior end (vs. vomerine forming short patch, see Fig. 3C in Smith & Ho 2018) (Smith et al. 2017; Smith & Ho 2018). Conger melanopterus differs from the Indian congener, C. cinereus, in having more predorsal vertebrae (14 vs. 9–11), longer predorsal length (24.0% vs. 12.8–14.1% TL), DFO behind the pectoral-fin tip (vs. DFO at middle of the pectoral fin), pectoral fin completely dark (vs. dark spot on pectoral fin), maxillary teeth in 2 rows (vs. 1), and larger head (18.5% vs. 11.5–12.7% TL) (Smith & Ho 2018). The new species further differs from C. conger, Conger marginatus Valenciennes, 1850, C. orbignianus, C. triporiceps, C. verreauxi, and C. wilsoni in having fewer vertebrae (141+ vs. 148–161 in C. conger; 148–153 in C. marginatus; 160–161 in C. orbignianus; 156–160 in C. triporiceps; 152–157 in C. verreauxi; 146–147 in C. wilsoni) (Kanazawa 1958). Further, C. melanopterus differs from Conger esculentus Poey, 1861, Conger oligoporus Kanazawa, 1958 and Conger philippinus Kanazawa, 1958 in having more total vertebrae (141+ vs. 132–133 in C. esculentus; 136–139 in C. oligoporus; 127–135 C. philippinus) (Kanazawa 1958; Smith & Ho 2018). The new species shares total vertebrae and body colouration with Conger jordani Kanazawa, 1958, but is readily distinguishable from the latter in having 3 SO pores (vs. 4), trunk length 1.1 in times the head length (1.4–1.9), vertical fins bases black (vs. white), larger head (18.5% TL vs. 13.3–14.3%), smaller eye (12.9% HL vs. 15.5–17.1% HL), trunk length 52.4% PAL (vs. 59.6–64.5% PAL), longer predorsal length (24% TL vs. 18.8–20.6% TL), and shorter tail (58.6% TL vs. 61.7–64.7% TL) (Kanazawa 1958; Smith & Ho 2018). The new species shares similar total vertebrae, pectoral rays, and colouration with Conger erebennus (Jordan & Snyder, 1901) from the Western North Pacific. But it readily differs from the latter in having fewer preanal vertebrae (36 vs. 40–42), preanal pores (34 vs. 37–40), head larger (18.5% HL vs. 16.3–17.3% HL), and pectoral fin 3.3 in HL (vs. 3 in HL) (Jordan & Snyder 1901; Kanazawa 1958; Smith et al. 2016). 1 Previously treated as Conger wilsoni Conger myriaster from the waters off Japan, Taiwan and China has a close total vertebrae count to C. melanopterus, and one specimen from Taiwan shares similar body colouration (See Fig. 6C in Smith & Ho 2018). But C. melanopterus readily differs from C. myriaster in having a larger head (18.5% TL vs. 12.3–14.9% TL), longer predorsal length (24.0% TL vs. 17.7–18.9% TL), trunk length 52.4% PAL (vs. 61.8–67.9% PAL), relatively smaller pectoral fin (30.7% HL vs. 35.9–43.1% HL), trunk length 1.1 times in head length (vs. 1.6–2.1), and maxillary teeth inner row ½ of outer row (vs. short) (Smith & Ho 2018). Remarks. Although several species of the genus Conger undergo changes in body colour, variation in pectoral fin shape, eyes shape, tooth loss and vertebral decalcification during maturity (see Smith & Ho 2018; Battaglia et al. 2020), the new species is significantly different in that teeth are retained and vertebral decalcification is not as intense and in possessing a larger head than all other species except C. macrocephalus, but differs from this species in other characters and genetically. We described the first new species of the genus Conger in 65 years. This joins C. cinereus and C. wilsoni as the third species of Conger known from the Western Indian Ocean. Further attempts to collect additional specimens were unsuccessful due to the difficulty of deep-sea collection and rarity. Though the species of the genus Conger are well-known for their large size and commercial value, knowledge of the taxonomic status and diversity of the species is limited (Smith & Ho 2018). After Kanazawa (1958), no new species have been described from this genus until now, and only a very few authors such as Asano (1962), Castle (1964, 1968), Smith (1989) and Smith & Ho (2018) had worked on the systematics of the genus Conger. Hence, the revision of this genus along with both morphological and phylogenetic analysis is needed to resolve the taxonomic and diversity ambiguity., Published as part of Kodeeswaran, Paramasivam, Smith, Id. G., Dhas, Deepa, Ajith Kumar, T. T. & Lal, Kuldeep Kumar, 2023, A new species of the congrid eel genus Conger (Anguilliformes: Congridae) from the southwest coast of India, pp. 474-484 in Zootaxa 5244 (5) on pages 475-483, DOI: 10.11646/zootaxa.5244.5.4, http://zenodo.org/record/7663852, {"references":["Bloch, M. E. & Schneider, J. G. (1801) M. E. Blochii, Systema Ichthyologiae Iconibus CX Ilustratum. Sumtibus auctoris impressum et Bibliopolio Sanderiano commissum, Berolini, lx + 584 pp., 110 pls.","Brevoort, J. C. (1856) Notes on some figures of Japanese fish taken from recent specimens by the artists of the U. S. Japan Expedition. In: Perry, M. C. (Ed.), Narrative of the Expedition of an American Squadron to the China Seas and Japan, performed in the years 1852, 1853, and 1854 under the command of Commodore M. C. Perry, United States Navy, by order of the Government of the United States. Vol. 2. U. S. Senate Ex. Doc. No. 79. 33 rd Congress. 2 nd Session. Beverley Tucker, Washington, D. C., pp. 253 - 288, pls. 3 - 12.","Kanazawa, R. H. (1958) A revision of the eels of the genus Conger with descriptions of four new species. Proceedings of the United States National Museum, 108 (3400), 219 - 267, pls. 1 - 4. https: // doi. org / 10.5479 / si. 00963801.108 - 3400.219","Mitchill, S. L. (1818) Description of three species of fish. Journal of the Academy of Natural Sciences, Philadelphia, 1 (2), 407 - 412.","Valenciennes, A. (1837) Poissons. Catalogue des principales especes de poissons, rapportees de l'Amerique meridionale. In: d'Orbigny, A. Voyage dans l'Amerique meridionale. P. Bertrand, Paris and V. Levrault, Strasbourg, 5 (2), 1 - 11.","Linnaeus, C. (1758) Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Impensis Direct. Laurentii Salvii, Holmiae, ii + 824 pp. https: // doi. org / 10.5962 / bhl. title. 542","Smith, D. G. & Ho, H. - C., (2018) Review of the congrid eel genus Conger (Anguilliformes: Congridae) in Taiwan. Zootaxa, 4454 (1), 168 - 185. https: // doi. org / 10.11646 / zootaxa. 4454.1.14","Smith, D. G., Jawad, L. & Al-Kharusi, L. H. (2017) New records and new information on four eel species from Oman. Journal of the Ocean Science Foundation, 28, 34 - 46. https: // doi. org / 10.5281 / zenodo. 996846","Valenciennes, A. (1850) Poissons. In: Eydoux, J. F. T. & Souleyet, F. A., Voyage autour du monde execute pendant les annees 1836 et 1837 sur la corvette La Bonite, commandee par M. Vaillant, Paris, Zoologie, 1 (2), pp. 155 - 216.","Poey, F. (1861) s. n. In: Memorias sobra la historia natural de la Isla de Cuba, acompanadas de sumarios Latinos y extractos en Frances. Tomo 2. Impr. de Barcina, La Habana, pp. 337 - 442. https: // doi. org / 10.5962 / bhl. title. 2485","Jordan, D. S. & Snyder, J. O. (1901) A review of the apodal fishes or eels of Japan, with descriptions of nineteen new species. Proceedings of the United States National Museum, 23 (1239), 837 - 890. https: // doi. org / 10.5479 / si. 00963801.23 - 1239.837","Smith, D. G., Schwarzhans, W. W. & Pogonoski, J. J. (2016) The identity of Conger japonicus Bleeker, 1879 (Anguilliformes: Congridae). Copeia, 104 (3), 734 - 737. https: // doi. org / 10.1643 / CI- 16 - 408","Battaglia, P., Smith, D., Ammendolia, G., Cavallaro, M., Maggio, T., Consoli, P., Guerrera, M. C., Andaloro, F. & Romeo, T. (2020) The last stage in the life history of the European conger eel Conger conger: a transformation before death. Journal of Fish Biology, 96 (2), 533 - 538. https: // doi. org / 10.1111 / jfb. 14223","Asano, H. (1962) Studies on the congrid eels of Japan. Bulletin of the Misaki Marine Biological Institute Kyoto University, 1, 1 - 143.","Castle, P. H. J. (1964) Congrid leptocephali in Australasian waters with descriptions of Conger wilsoni (Bl. and Schn.) and C. verreauxi Kaup. Zoology Publications from Victoria University of Wellington, 37, 1 - 45.","Castle, P. H. J. (1968) The congrid eels of the western Indian Ocean and the Red Sea. Ichthyological Bulletin Department of Ichthyology Rhodes University, 33, 685 - 726.","Smith, D. G. (1989) Family Congridae. In: Bohlke, E. B. (Ed.), Fishes of the western North Atlantic. Memoirs of the Sears Foundation for Marine Research, 1 (Part 9), pp. 460 - 567."]}

A new species of Conger eel is described from a single specimen (569 mm total length) collected off Kanyakumari, Southwest coast of India, Arabian Sea. The following characters distinguish the new species from other congeners: dorsal-fin origin behind the pectoral-fin tip; head larger, 18.5% TL; longer predorsal length 24.0% TL; relatively shorter trunk, uniserial teeth at the posterior end of vomerine patch; body blackish to dark brown; pectoral fin completely darker; cephalic pores rim whitish; SO pores 3; IO pores 6; pectoral rays 19; total vertebrae 141+. Genetic analysis of the mitochondrial COI gene revealed that the new species is closely related to Conger verreauxi Kaup, 1856 and Conger macrocephalus Kanazawa, 1958, with a genetic divergence of 5.7% and 5.9% respectively.

Huang, Wen-Chien, Liao, Te-Yu, Tan, Heok Hui (2023): Uropterygius cyamommatus, a new moray eel (Anguilliformes: Muraenidae) from anchialine caves in Christmas Island, Australia, and Panglao Island, the Philippines. Raffles Bulletin of Zoology 71: 268-278, DOI: 10.26107/RBZ-2023-0021

Gymnothorax tamilnaduensissp. nov., a new species of short brown unpatterned moray, is described, based on four specimens ranging from 272–487 mm total length collected from the trawl bycatch landings at Mudasalodai fish landing centre, off Cuddalore coast, Tamil Nadu, southeast coast of India. The new species is distinguished by the following combination of characters: origin of dorsal fin at middle of rictus and gill opening, anus just before mid-body, series of lines of small dark spots present on head and a single line of black spot-on mid-line of body, jaw pores with white rim, anal-fin margin whitish, 3 pre-dorsal vertebrae, 56–59 pre-anal vertebrae and 139–150 total vertebrae. The new species differs from its known Indian water congeners by having series of lines of small dark spots present on the head and a single line of black spots on the mid-line of the body (vs. absent in all the three congeners in India), serrated teeth (vs. smooth), jaw pores with white rim (vs. black to brown in others) and higher vertebral count (139–150 vs. 134–138 in others). Our morphological and molecular analyses show that the new species forms a distinct clade from its congeners and these data support the status as a new species.

Microsatellite loci were screened from the genomic data of Dysomma anguillare and their composition and distribution were analysed by bioinformatics for the first time. The results showed that 4,060,742 scaffolds with a total length of 1,562 Mb were obtained by high-throughput sequencing and 1,160,104 microsatellite loci were obtained by MISA screening, which were distributed on 770,294 scaffolds. The occurrence frequency and relative abundance were 28.57% and 743/Mb, respectively. Amongst the six complete microsatellite types, dinucleotide repeats accounted for the largest proportion (592,234, 51.05%), the highest occurrence frequency (14.58%) and the largest relative abundance (379.27/Mb). A total of 1488 microsatellite repeats were detected in the genome of D. anguillare, amongst which the hexanucleotide repeat motifs were the most abundant (608), followed by pentanucleotide repeat motifs (574), tetranucleotide repeat motifs (232), trinucleotide repeat motifs (59), dinucleotide repeat motifs (11) and mononucleotide repeat motifs (4). The abundance of microsatellites of the same repeat type decreased with the increase of copy numbers. Amongst the six types of nucleotide repeats, the preponderance of repeated motifs are A (191,390, 43.77%), CA (150,240, 25.37%), AAT (13,168, 14.05%), CACG (2,649, 8.14%), TAATG (119, 19.16%) and CCCTAA (190, 19.16%, 7.65%), respectively. The data of the number, distribution and abundance of different types of microsatellites in the genome of D. anguillare were obtained in this study, which would lay a foundation for the development of high-quality microsatellite markers of D. anguillare in the future.

Along with the mysteries of their body's shape like snakes, marine eels have fascinated biologists for centuries. Information on the molecular taxonomy of marine eels is scarce from the Southeast Indian region and hence, the present study aimed to barcode marine eels collected from Kasimedu fishing harbor, Chennai, Tamil Nadu. A total of 44 specimens were collected and DNA barcoding was done with a COI marker. The evolutionary history was inferred using the BA method. We observed 17 species, 10 genera, 4 families from the suborder Congroidei of which the genus Ariosoma and Conger were found to be predominant. The species of the family Muraenesocidae and Congridae are highly variable. The average Kimura two-parameter (K2P) distances within species, genera, and families were 3.08%, 6.80%, 13.80%, respectively. Maximum genetic distance (0.307) was observed between the species Muraenesox cinereus and Ariosoma sp.1. BA tree topology revealed distinct clusters in concurrence with the taxonomic status of the species. A deeper split was observed in Uroconger lepturus. We sequenced for the first-time barcode of Sauromuraenesox vorax and a new species Ophichthus chennaiensis is the gap-filling in identifying this taxon in the Indian context. We found a correct match between morphological and genetic identification of the species analyzed, depending on the cluster analysis performed (BINs and ASAP). This demonstrates that the COI gene sequence is suitable for phylogenetic analysis and species identification.

In October 2020, a single specimen of the daggertooth pike conger, Muraenesox cinereus (Forsskål, 1775), was caught by longline at a depth of 120 m, from the Mediterranean coast of Turkey. This species has been recorded from the Mediterranean for the second time after approximately four decades. This new finding shows that the distribution of the species has expanded.

Bascanichthys kabeyawan Hibino & Ho, sp. nov. English name: Kabeyawan Sand Eel Figs. 1‒2; Table 1 urn:lsid:zoobank.org:act: E76966BF-BEB0-4C89-8686-0E661A23D84F Holotype. NMMB-P 36052, 526 mm TL, ca. 22°03'42.3"N 120°42'23.6"E, mouth of Shi-Chong River, Pingtung, southwestern Taiwan, trap net (fyke net), 8 Jan. 2022. Diagnosis. An extremely elongate species of Bascanichthys with the following combination of characters: head 4.6% TL; tail 52.3% TL; body depth at gill opening 1.1% TL; predorsal-fin length 58.4% HL; snout length 10.9% HL; body bicolored, head without bands; lateral-line pores anterior to anus 104; vertebral formula 4-103-224; and dorsal-fin origin slightly behind middle of head and above fourth lateral-line pore. Description. Counts and measurements are shown in Table 1. Body extremely thin and slender (Fig. 1), nearly circular in cross-section to anterior part of tail, then becoming slightly compressed laterally, its depth at gill opening 92 times in TL. Skin mostly smooth on entire body, except for slightly wrinkling on cheek and anterior branchial basket regions; anus a long slit, situated at around middle of total length, preanal length 2.1 in TL. Head small; branchial basket well-expanded, clearly deeper than trunk, its deepest depth 3.1 times in HL. Snout short, bluntly pointed from dorsal view and slightly pointed from side, its length 9.2 in HL; posterior half of snout bisected by a deep groove ventrally (2 flashy vertical lamellae present). Eye small, its center behind mid-upper jaw, posterior margin of eye clearly before rictus, its diameter 4.0 in upper jaw length and 19.9 in HL; interorbital space narrow, its width 1.4 times eye diameter and 14.0 in HL; interbranchial space narrow, its width 13.4 in HL; numerous papillae present on anterior half of head, including snout, lips, chin, cheek, top of skull and interorbital space; anterior nostril tubular, extending rather downward than forward from the snout; posterior nostril a hole along upper lip, covered by broad flap extending slightly below edge of mouth gape, opening towards posteroventrally; a single compressed fleshy barbel in front of the posterior nostril. Rictus situated clearly behind a vertical through posterior margin of eye; no short fold at posterior end of mouth gape; lower jaw short, tip extends to near the posterior margin of anterior nostril tube, distance from tip of snout to anterior end of lower jaw slightly longer than eye diameter; gill opening lateral, located ventral half of body. Sensory pores on head and body large and well apparent (Fig. 2A); supraorbital pores 1 (ethmoid)+3 on dorsal surface of snout and interorbital space, 4th pore above middle of eye; infraorbital pores 3+2 (right) or 3+3 (left), 1 above the barbel (in front of posterior nostril), 2 below eye along upper jaw, and 2 (right) or 3 (left) in a vertical row behind eye; mandibular pores 4, anterior 3 along lower jaw and the 4th slightly behind rictus; preopercular pores 2; interorbital pore 1; supratemporal pores 3 (single mid-temporal pore). A row of tiny sensory papillae on outer surface of gill basket. Lateral-line pores relatively large, opening clearly below the lateral-line canal, forming waveshape; 3 pores before dorsal-fin origin; 10 before gill opening, forming an arch; 104 anterior to anus; total pores 213, the last at about 1/2 HL in advance of tail tip. All teeth (Fig. 2B) moderately small, conical and closely spaced; intermaxillary with 3 large teeth arranged in a triangle, followed by a gape and then single row of 11 small teeth on vomer; maxilla with single row of teeth on anterior third, then biserial on the rest, 16 teeth on outer row and 21 on inner row; mandible with single row of 21 teeth on each side. Dorsal and anal fins low but obvious, ending at near tip of tail; dorsal-fin origin slightly behind a vertical through middle of head, above fourth lateral-line pore, 0.4 HL before gill opening; pectoral fin minute, flap-like with about 3 short rays, located at upper corner of gill opening, its length 2.6% HL and base height 5.4% HL (best seen with magnification). Color in both fresh and preserved condition (Figs. 1A‒C): head uniformly grayish black with ventral surface slight paler; body grayish black dorsally and uniformly pale on ventral surface, forming clearly bicolored with the boundary slightly below lateral line; lateral-line pores and adjacent regions without pigments; all fins pale without pigments, except for some dark pigments on pectoral fin; a small cluster of pigments in front of anus; mouth cavity pale with few dark pigments. Etymology. The scientific name kabeyawan (Taiwanese: ku-piah-uan), used as a noun, is an old name of the type locality Checheng, a territory of aboriginal Paiwan people documented in the Dutch occupation period (1624‒ 1662). Distribution. Currently only known from the single specimen collected from mouth of Shih-chong River, Pingtung, southern Taiwan at depth about 1 meter. Ecological note. The specimen was collected by trap net operated by a local fisherman who targeted on glass eel of Anguilla spp. It was collected together with other snake eels, such as Lamnostoma sp. and Ophichthus sp., and was likely chasing the fish larvae to the river mouth.

Bathycongrus melanostomus sp. nov. English name: Black mouth conger Figs. 1A–D, 2A–C, 3, 4; Table. 1 Holotype. TOU-AE 7271 (439 mm TL), ca. 23°29'N, 121°30'E, off Shihtiping, Hualien, eastern Taiwan, hook and line, ca. 300 m, 23 Jan. 2015, coll. J.-S. Chiu. Paratypes. TOU-AE 7272 (371 mm TL), ca. 23°45'N, 121°34'E, off Shuilien, Hualien, eastern Taiwan, hook and line, ca. 300 m, 27 Jan. 2015, coll. J.-S. Chiu. NMMB-P36072 (formerly TOU-AE 5560) (420 mm TL), ca. 23°18'N, 121°26'E, off Changbin, Taitung, eastern Taiwan, hook and line, ca. 300 m, 13 Jun. 2010, coll. J.-S. Chiu. Diagnosis. A moderately elongate species of Bathycongrus with uniformly small teeth on vomer forming an oval patch; a strongly reduced caudal fin; abdomen, mouth cavity and gill chamber blackish. It can be further distinguished from the congeners by dorsal and anal fins grayish with black margins; a short, broad and blunt snout, intermaxillary teeth barely exposed when mouth closed; pre-anal vertebrae 31, precaudal vertebrae 41; total vertebrae 133–135; and pre-anal lateral-line pores 31. Description. The following values are given for the holotype, followed by the range of the two paratypes in parentheses. Body rather stout, robust, rounded in cross section anteriorly, becoming more compressed behind anus and posterior portion; head moderately slender, head depth and width slightly smaller than those of trunk; trunk moderately long, its length 1.5 (1.6–1.7) times of head length; tip of tail rounded, not filiform; anus situated at near anterior two fifths of total length (when tail complete), pre-anal length 36.4 in TL; tail relatively short, tail length 63.6 in TL. Dorsal-fin origin behind tip of pectoral fin, continuous around tip of tail with caudal and anal fins. Anal fin begans immediately behind anus. Pectoral fin well developed, pointed distally with a narrow base. Caudal-fin rays strongly reduced, with membranes forming a small flap. Gill opening large, similar to eye diameter or slightly smaller in length, its upper end nearly opposite to middle of pectoral-fin base. Interbranchial width much broad, more than twice of width of gill opening (Fig. 1). Head relatively large and robust, its length 14.6% (13.5–14.6%) TL, deepest at about occiput, slightly tapering anteriorly to this point; dorsal profile nearly flat from occiput to internasal space; snout short and rounded, its length 1.7 (1.6–1.7) times eye diameter, slightly projecting beyond lower jaw; lower jaw longer than snout; fleshy part of snout without median keel on underside, projecting anteriorly beyond anterior end of intermaxillary tooth patch; rictus below middle of eye. Anterior nostril tubular, near tip of snout, directed ventrolaterally. Posterior nostril elliptical, with clear rim, in front of eye above mid-eye level. Upper lip with flange strongly reduced, lower lip with a well-developed downturned flange. Tongue free, long, and broad. Lateral line complete, first pore on each side slightly enlarged, the canal extended to caudal-fin base; 13 pores before dorsal-fin origin, 5 pores before pectoral-fin base, 31 pores before anal-fin origin; total pores 109 (108–109), last one running to about 1 head length before rear tip. Head pores various in size (Fig. 3). Supraorbital canal with 3 pores, the first (ethmoidal pore) on ventral side of snout tip, just ahead of lip; the second enlarged and immediately in front of anterior nostril; the third greatly enlarged and immediately above anterior nostril. Infraorbital canal with 5 pores, first pore at dorsal-posterior corner of anterior nostril; the second and third enlarged, between anterior and posterior nostrils, both shaded by upper flange; the fourth small, below anterior margin of eye; the fifth small, behind rictus. No pore on frontal region and behind eye. Preoperculomandibular canal with 9 pores, 5 before and 4 behind rictus, second and posteriormost 2 pores (preopercular) enlarged. Supratemporal with a single, small medial pore. Teeth (Fig. 4) uniformly small in size, conical to blunt. Intermaxillary in about 5 transverse rows, not well separated from maxillary and vomerine teeth, barely excluded from closed mouth. Maxillary and mandibular teeth in bands, wider anteriorly, roughly in 4 or 5 rows in anterior three-fourths, followed by a narrower, curved band of 2 or 3 rows of smaller teeth; outermost teeth slightly smaller than those of inner rows. Vomerine teeth blunt, shorter than those of intermaxillary, forming an oval patch, patch with length longer than width, reaches to level of posterior nostril, in about 8 rows middly. Coloration. When fresh (Figs. 1A–B, 2A–B), body uniformly dark grey to brown; vertical fins black with gray bases. Dark papillae outlining supratemporal canal and along dorsal surface; an indistinct patch of pigments on opercle in front of pectoral-fin base. Pectoral fin yellowish with black margin. Lateral-line pores white. Anterior portions of snout, lips and chins whitish. Mouth cavity, gill chamber black. When preserved (Figs. 1C, 2C), body uniformly dark brown. Anterior portions of snout, lips and chins whitish. Mouth cavity, gill chamber, peritoneum, stomach, and intestine black. Pectoral fin brown with black margin. Lateral-line pores white. Measurement for holotype (in mm): total length 439.0; head length 64.0; predorsal length 89.0; preanal length 160.0; trunk length 96.0; tail length 279.0; depth at gill opening 34.9; width at gill opening 22.4; depth at mid-anus 34.3; eye diameter 8.6; interorbital width 15.6; snout length 14.5; interbranchial width 17.2; pectoral-fin length 22.3; gill-opening length 9.0; upper-jaw length 17.7; lower-jaw length 16.5. Size. The largest specimen is a mature male measured 439 mm TL. Etymology. The specific name is from the Greek melano, black and stomus, a mouth, in refer to the black mouth. Distribution. Known from the type series collected from eastern Taiwan off three localities, Changbin, Shihtiping and Shuilien at depth about 300 m., Published as part of Huang, Jian-Fu, Ho, Hsuan-Ching, Chen, Hong-Ming & Chan, Tin-Yam, 2022, A new species of the congrid eel genus Bathycongrus (Order Anguilliformes) from eastern Taiwan, pp. 78-86 in Zootaxa 5189 (1) on pages 79-83, DOI: 10.11646/zootaxa.5189.1.10, http://zenodo.org/record/7119260

Bascanichthys ryukyuensis Hibino, Yamashita & Sakurai, sp. nov. New standard Japanese name: Kazura-umihebi New English name: Vine-like Sand Eel Figs. 3‒4; Table 1 urn:lsid:zoobank.org:act: 4B91D8E3-F13A-4B4A-9FDC-6F4F51049E26 Bascanichthys sp.: Hibino et al. 2021: 17, fig. 6a (Okinawa-jima Island, Japan). Holotype. FRLM 52250, 627 mm TL, female, Yakena, eastern coast of Yokatsu Peninsula, Okinawa-jima Island, Ryukyu Islands, Japan, stranded specimen found at beach (0–1 m depth) around seagrass bed, 26 Jan. 2016, coll. K. Yamashita. Paratype. FRLM 52251, 516 mm TL, male, collected with holotype. Diagnosis. An extremely elongate species of Bascanichthys with the following combination of characters: head 3.7–4.3% TL; tail 43.3–44.2% TL; predorsal-fin length 40.7–45.4% of head length; snout length 11.3–13.1% of head length; body pale brown, head without distinct dark bands after preservation; lateral-line pores anterior to anus 114–118; total vertebrae 207–216, mean vertebral formula 2-116-212; and dorsal-fin origin slightly before middle of head and before first lateral-line pore. Description. Counts and measurements are shown in Table 1. Body extremely elongate (Fig. 3A), subcylindrical, tail laterally compressed posteriorly, its depth at gill opening 83‒91 times in TL. Skin generally smooth, with weak longitudinal wrinkles dorsally; tail shorter than head and trunk, preanal length 1.8 in TL. Head small, skin with many longitudinal wrinkles except snout; dorsal contour smoothly curved; branchial basket convex, well-expanded, its deepest depth 2.4–2.7 times in HL. Snout stout and broad, tip weakly pointed and relatively pointed from dorsal view (Fig. 3B, C), its length 7.6–8.8 in HL; posterior half of snout bisected by a deep groove ventrally; interorbital region smooth, slightly convex. Eye small, positioned about mid-jaw, its diameter 3.8–5.0 in upper jaw length and 18.4–19.7 in HL; interorbital space narrow, its width 1.6–2.1 times eye diameter and 9.4–11.6 in HL; numerous papillae present on snout, interorbital space, temporal and lips, rather dense in holotype but scattered in paratype; anterior nostril tubular, extending downward; posterior nostril a hole covering by a compressed thin skin, its opening towards posteroventrally; upper lip with several fleshy thorn-shaped barbels (Fig. 4A), one between nostrils, very minute barbels along with the barbel in left side of holotype; and two posterior to posterior nostril (three in left side of paratype); rictus relatively short, behind posterior margin of eye; lower jaw short, distance from tip of snout to anterior end of lower jaw slightly longer than eye diameter; gill opening lateral, located at ventral half of body. Sensory pores small but conspicuous (Fig. 4B); supraorbital pores 1 (ethmoid)+3; infraorbital pores 3+3, 1 between nostrils, 2 below eye along upper jaw, and 3 behind eye in a vertical row; mandibular pores 5, the last pore slightly behind rictus; preopercular pores 2; interorbital pore 1; supratemporal pore 3 (single mid-temporal pore). Lateral line nearly completed, pores conspicuous, 0 pore before dorsal-fin origin, 8 anterior to gill opening, 118 anterior to anus and total 207 in holotype (0, 9, 114 and 195, respectively, in paratype), the last just before tip of tail about 1/3 HL. All teeth small, conical, and relatively pointed; teeth on maxilla in holotype arranged uniserial, in paratype partly biserial but generally uniserial (Figs. 4B, C); dentary teeth biserial; 5 intermaxillary teeth arranged as chevron; vomerine teeth biserial in holotype, mid-part of vomer partly triserial in paratype. Dorsal and anal fins very low, ending at near tip of tail, end of anal fin slightly behind that of dorsal fin; dorsalfin origin before middle of head, right behind the mid-temporal pore and before the first lateral-line pore; pectoral fin extremely minute, flap-like, located at anterior corner of gill opening, its length 13.1–20.4% HL and base height 26.2–44.1% HL. Color when fresh condition (after refrigeration; Fig. 3): body purplish pale brown, darker dorsally; head yellowish, snout and lower jaw deep, tip of snout yellowish brown; fins dusky white. Color in preserved condition: purplish and yellowish color faded. Body pale brown, darker dorsally; head slightly paler than body, in paratype tip of snout dark brown and pale dusky white band between tip of snout and eye; fins dusky white. Etymology. The specific name ryukyuensis is derived from the type locality. Distribution. Only known from the two specimens collected from shore of Okinawa-jima Island, Ryukyu Islands, Japan. Ecological note. The present specimens were collected as stranded specimens caused by the extremely low temperatures by a serous cold wave coming from the Arctic (Hibino et al. 2021). In the type locality, several species of Muraenidae, Ophichthidae, Apogonidae, Syganidae, etc., were also collected at the same time.

Bascanichthys Jordan & Davis, 1891 Bascanichthys Jordan & Davis, 1891:621 (type species: Caecula bascanium Jordan, 1884, by original designation)., Published as part of Hibino, Yusuke, Yamashita, Kenta, Sakurai, You & Ho, Hsuan-Ching, 2022, Two new species of the snake eel genus Bascanichthys (Anguilliformes: Ophichthidae) from the northwestern Pacific, pp. 103-113 in Zootaxa 5189 (1) on page 104, DOI: 10.11646/zootaxa.5189.1.12, http://zenodo.org/record/7119307, {"references":["Jordan, D. S. & Davis, B. M. (1891) A preliminary review of the apodal fishes or eels inhabiting the waters of America and Europe. United States Commission of Fish and Fisheries, Report of the Commissioner, 16, 581 - 677., pls. 73 - 80.","Jordan, D. S. (1884) List of fishes from Egmont Key, Florida, in the Museum of Yale College, with description of two new species. Proceedings of the Academy of Natural Sciences of Philadelphia, 36, 42 - 46."]}