Bathycongrus villosus, Smith & Karmovskaya & Silva, 2020

Smith, David G., Karmovskaya, Emma S. & Silva, João Paulo Capretz Batista Da, 2020, A new congrid eel (Teleostei: Anguilliformes: Congridae) from the Western Pacific with an analysis of its relationships, Zootaxa 4845 (2), pp. 191-210 : 192-195

Bathycongrus villosus sp. nov.

Figs. 1–3 ; Tables 1–3

Holotype: MNHN 1997-3795 (236 mm TL, female), Vanuatu, 15 о 36’ S, 167 о 16’ E, depth 182–215 m, beam trawl, 5 October , 1994, station CP 1086, C. R. V. “Alis”, MUSORSTOM 8.

Paratypes: USNM 344104 (2 females, 239–296 mm), Albay Gulf , Philippines, 13° 10’ 16” N, 123° 50’ 12” E to 13° 10’ 14”N, 123° 52’ 22 “E, depth 174–190 m, 30-m otter trawl, RV “Fishery Researcher 1”, 22 Sep 1995 ; USNM 451061 (1 male, 252 mm, stained and partly dissected), same data as USNM 344104 .

Material for comparison. Bassanago albescens: USNM 365200 (12, 367– 508 mm), 37°24’06”S, 54°39’42”W, depth 187–327 m, 5 May 1975; USNM 404584 (21, 354–605) same data as USNM 365200 ; USNM 427184 (1, 343, stained and partly dissected), same data as USNM 365200. Conger cinereus Rüppell, in Klunzinger, 1871 : CSIRO H 8518-01 (1, 382), Solomon Is. , 8° 17’S, 157° 09’E, 9 Jul 1987 ; USNM 451062 (1, cleared and stained), Red Sea , Gulf of Aqaba, depth 0–2 m, 5 Sep 1969 .

Diagnosis. A moderately elongate congrid eel of the subfamily Congrinae , with small hair-like epidermal processes on surface of body and head. Tail moderately attenuate. Dorsal-fin origin behind origin of pectoral fin. Snout slightly projecting beyond lower jaw. Upper labial flange rudimentary. Anterior and posterior nostrils tubular, posterior at mid-eye level. Teeth conical, relatively small, all about the same size, in bands tapering posteriorly on jaws; intermaxillary patch broader than long, teeth slightly exposed when mouth closed, in 3–4 transverse rows; vomerine teeth in an elongate patch, blunt conical, none enlarged, roughly in 4–5 rows anteriorly and 2 rows posteriorly. Total vertebrae 121–126, preanal lateral-line pores 26–27. Lateral-line pores tubular. Head pores small.

Description Counts and measurements of individual specimens are provided in Table 1. Values given for holotype, with those of paratypes in parentheses. Measurements as % TL: preanal length 33.9 (35.1–36.1), predorsal length 16.1 (17.6–18.7), head length 14.8 (15.5–16.3), trunk length 19.1 (18.9–20.5), depth at anus 8.1 (5.7–7.1); as % of head length: snout length 22.9 (23.4–23.8), horizontal eye diameter 20.3 (16.5–21.2), postorbital length 56.9 (55.4–59.7), snout to rictus 29.7 (30.8–33.7), gill opening 15.4 (9.4–12.2), interbranchial 28.6 (20.5–28.9), pectoral-fin length 37.1 (32.7–35.1). Meristic characters: preanal lateral-line pores 26 (26–27), supraorbital (SO) pores 3, infraorbital (IO) pores 5, preoperculomandibular (POM) pores 10, supratemporal commissure (STC) 1 pore. Predorsal vertebrae 8 (8–10), preanal vertebrae 28 (29–30), precaudal vertebrae 36 (35–37), total vertebrae 123 (121–126). Pectoral-fin-rays 12 (13), dorsal-fin-rays 284 (268 +, ca 278), preanal dorsal-fin-rays 54 (50–59), anal-fin-rays 217 (205 +, ca 215), caudal-fin rays ca. 4+5. Branchiostegal rays 9 (10).

Body moderately elongate, robust, round in cross section anteriorly, tapering and compressed behind anus to tip of caudal region; tip of tail slender but not filiform; anus slightly posterior to anterior third of total length. Dorsal fin begins slightly ahead of midpoint of appressed pectoral fin. Anal fin begins immediately behind anus under the 26 th– 27 th lateral-line pore. Pectoral fin well developed. Gill opening large, upper end slightly below midpoint of pectoral-fin base. Interbranchial nearly twice gill opening. Small villiform transparent epidermal processes over surface of head and body, some of them pigmented by minute melanophores. Myorhabdoi absent, dorsal- and analfin rays segmented.

Head well differentiated from trunk, deepest midway between posterior margin of eye and gill opening, its length contained 2.2–2.3 times in preanal and 6.1–6.7 in total length; snout about equal to eye diameter, projecting slightly beyond anterior end of lower jaw; rictus below middle of eye. Upper lip with reduced upturned flange; lower lip thick, with well-developed downturned flange. Anterior nostril a short tube, near tip of snout, directed anteroventrally. Posterior nostril tubular, at mid-eye level.

Lateral line not complete, ca.100 small tube-like pores along lower edge of lateral-line canal; 26–27 pores before anus. Head pores relatively small, none greatly enlarged ( Fig. 3A ). Supraorbital canal with three pores: the first (ethmoidal) small, on ventral side of tip of snout; the second somewhat enlarged and immediately in front of anterior nostril; the third somewhat enlarged and immediately above anterior nostril. Infraorbital canal with five pores: the first immediately behind anterior nostril; the second between anterior and posterior nostrils; the third below posterior nostril; the fourth below anterior part of eye; the fifth behind rictus and below posterior part of eye; no adnasal pore, and no pores behind eye. Preoperculomandibular canal with ten pores, seven in mandibular canal and three behind mandible; the third mandibular pore round and noticeably enlarged. Supratemporal commissure with one medial pore.

Teeth rather small, conical, all about the same size ( Fig. 3B ). Intermaxillary patch slightly broader than long, teeth in three to four transverse rows, slightly separated from maxillary and vomerine teeth, partially excluded from closed mouth. Maxillary and mandibular teeth in bands, wider anteriorly, roughly in five to six rows anteriorly tapering to two rows posteriorly. Vomerine tooth patch longer than broad, reaches to level of posterior nostril; teeth blunt-conical, larger posteriorly, in three to four irregular longitudinal rows.

Gas bladder terminates far behind anus. Stomach long, reaching about three-quarters of distance from gill opening to anus.

Color in life unknown. Color in preservative yellowish-brown to medium brown. Large, diffuse, darkish spot below lateral line in front of pectoral fin. Body mottled with tiny pointed melanophores. Vertical fins pigmented in posterior caudal part but not edged in black. No traces of larval pigmentation. Peritoneum mostly pale, slightly pigmented on dorsal side; intestine dark; stomach black. Oral cavity pale; branchial cavity largely pale with some scattered melanophores.

Size range of specimens 236–296 mm TL. Three of the specimens are females with well-developed ovaries, one is a male. Apparently a small species, probably not greatly exceeding 300 mm TL.

Etymology. Referring to the small dermal villi or papillae on the head and body.

Remarks. In three of the four specimens, the dorsal-fin origin is over the eighth vertebra. In the other specimen, it is between the ninth and tenth vertebrae.

Figures

FIGURE 1. Bathycongrus villosus sp. nov. Holotype, MNHN 1997-3795, 236 mm TL.

FIGURE 2. Bathycongrus villosus sp. nov. Paratype, USNM 344104, 296 mm TL. A, Whole; B, Head.

FIGURE 3. Bathycongrus villosus sp. nov. Holotype, MNHN 1997-3795, 236 mm TL. A, Head; B, Upper teeth.