Bathyuroconger hawaiiensis, Smith & Ho & Tashiro, 2018

Smith, David G., Ho, Hsuan-Ching & Tashiro, Fumihito, 2018, Eels of the genus Bathyuroconger in the northwestern Pacific, with descriptions of four new species (Anguilliformes: Congridae), Zootaxa 4454 (1), pp. 147-167 : 160-161

Bathyuroconger hawaiiensis sp. nov.

English name: Hawaiian large-toothed conger

Figs. 4 , 8B ; Tables 2, 3

Bathyuroconger vicinuS (non Vaillant, 1888): Smith, 1989a:541; Chave & Mundy, 1994:381; Mundy, 2005:140.

Holotype. USNM 348215 (392 mm), Hawaiian Is. north of Maui , 21.10°N, 156.23°W, 640‒686 m, Townsend Cromwell sta. 35-24, 5 Apr. 1968.

Paratypes. BPBM 21071 (7, 241‒315), Hawaiian Is., 21.08°N, 156.18°W, 623‒667 m, Townsend Cromwell sta. 40-87, 23 Nov. 1968 USNM 441777 (2, 280‒292), same data as holotype.

Non-types (detailed counts and measurements not taken). BPBM 24336 (2, 600‒675), 21.10°N, 156.22°W, 631‒705 m, Townsend Cromwell sta. 40-86, 23 Nov. 1968. BPBM 25042 (2, 280‒335, same data as BPBM 24336 . BPBM 24044 (4, 340‒645, 21.08°N, 156.18°W, 623‒667 m, Townsend Cromwell sta. 40-87, 23 Nov. 1968. BPBM 25072 (1, 415), Pailolo Channel, mid-channel, 650 m, 6 Mar. 1971 . BPBM 25074 (1, 434), Pailolo Channel, midchannel, Townsend Cromwell sta. 52- 88, 10 Mar 1971. BPBM 25090 (3, 619‒694), 21.02°N, 156.13°W, 860 m, Townsend Cromwell sta. 61-66, 26 Oct. 1972.

Diagnosis. A species of Bathyuroconger with a slightly reduced gill opening, separated from pectoral-fin base by a distance of less than diameter of gill opening; total vertebrae 201‒210; color medium to dark brown.

Description. Measurements in %TL: PAL 34.7‒38.7, PDL 12.8‒14.8, HL 12.2‒14.3, TR 22.5‒25.2, DA 4.8‒ 5.7. In % PAL: PDL 34.5‒40.2, HL 34.0‒38.6, TR 61.4‒66.0, DA 13.6‒15.0. In % HL: S 26.1‒30.0, E 13.8‒18.0, IOW 11.3‒13.8, UJ 37.4‒44.5, GO 6.8‒11.3, IB 10.2‒16.6, PL 18.8‒31.7. Pores: PDLL 8, PPLL 7, SO 3, IO 5, POM 9‒10, ST 1. Vertebrae: PDV 10‒13, PAV 51‒55, PCV ca. 58‒63, TV 201‒210.

Body slender, cylindrical anteriorly, gradually tapering and compressed posteriorly. Trunk short, trunk length 1.6‒1.9 times head length. Tail thin, anus anterior to mid-body at slightly more than one-third total length. Dorsal and anal fins confluent with caudal, dorsal fin begins slightly behind base of pectoral fin, anal fin begins immediately behind anus. Head stout, rounded, deeper than body; jaws nearly equal. Snout short and blunt, rounded in dorsal view, about 1.5‒2.1 times eye diameter. Eye moderate, over posterior third of upper jaw, posterior margin at level of rictus; interorbital space slightly less than eye diameter. Anterior nostril short and tubular, at front of snout; posterior nostril in front of mid-eye, a simple pore. Gill opening reduced, its upper margin not contacting base of pectoral fin, separated from base of fin by a distance of about half diameter of gill opening.

Head pores moderately enlarged, not elongate and slit-like. Supraorbital pores 3; first pore small, at tip of snout on edge of upper lip, opening ventrally; second pore larger, at level of and anterior to anterior nostril; third pore slightly larger and above posterior margin of anterior nostril; no pores on interorbital space. Infraorbital pores 5; first immediately behind anterior nostril; second between anterior and posterior nostrils; third below anterior margin of eye; fourth below posterior third of eye; fifth behind rictus; no pores behind eye. Preoperculomandibular pores 10; 7 on mandibular section, 6 before and 1 behind rictus; 3 on preopercular section, progressively larger posteriorly, the last one at about level of first lateral-line pore. One median supratemporal pore, anterior to first lateral-line pore. Lateral line complete, lateral-line pores large; predorsal 8, prepectoral 7.

Vertebrae: predorsal 10‒13, preanal 51‒55, precaudal ca. 58‒63, total 201‒210.

Teeth pointed, variable in size. Intermaxillary teeth in 2 transverse rows of about 4‒6 teeth each, enlarged and fang-like, exposed when mouth closed. Vomer with 2 enlarged median teeth, with a few smaller teeth around and behind, the row relatively short. Maxillary teeth in 3 rows anteriorly and 2 posteriorly, the outer teeth larger. Dentary teeth in about 3‒4 irregular rows anteriorly narrowing to 2 rows posteriorly, the outer teeth larger; the anteriormost teeth enlarged and fang-like, exposed when mouth closed.

Color in preservative medium to dark brown; interior of mouth with some dark pigment; gill cavity and digestive tract black.

Distribution. Hawaiian Islands. Bathymetric range 600‒ 860 m.

Etymology. Named for the type locality.

Remarks. This species has been known for some time, but it was identified as Bathyuroconger vicinus , which has been considered world-wide in distribution. The difference in the form of the gill opening was not noticed previously. The high vertebral count separates it from all other known species of Bathycongrus except the B. cf. vicinus specimens reported below, which have an unreduced gill opening in contact with the pectoral-fin base. The lateral-line pores in the type specimens could not be counted because of damage to the skin on the side of the body.

Figures

FIGURE 4.. Scatter plots demonstrating the different mophormetric proportion of Bathyuroconger species in present study. A. gill opening height (%HL) versus preanal length. B. Head length (%PAL) versus preanal length.

FIGURE 8. Lateral view of head of three Bathyuroconger species. A. B. fowleri sp. nov., paratype, USNM 93372, 497 mm TL. B. B. hawaiienSiS, holotype, USNM 348215, 392 mm TL. C. B. parvibranchialiS, holotype, USNM 92346, 645 mm TL.