Bathygadus melanobranchus Vaillant, 1888

Bañón, Rafael, Arronte, Juan Carlos, Barros-García, David, Vázquez-Dorado, Sandra & Carlos, Alejandro De, 2013, Taxonomic study of Bathygadidae fishes (Gadiformes) from Atlantic Spanish waters combining morphological and molecular approaches, Zootaxa 3746 (4), pp. 552-566 : 561-562

Bathygadus melanobranchus Vaillant, 1888

Fig. 5 .

Bathygadus melanobranchus Vaillant, 1888: 206 , Pl. 18 ( Figs. 1-1 e). Morocco coast, 32°31'N, 9°48'W, station 33, depth 1,350 meters. Lectotype: MNHN 1886-0112. Farran, 1924: 120–121 (description); Parr, 1946: 8–17 (description, key); Iwamoto, 1970: 327–352 (description, key); Marshall & Iwamoto, 1973: 518–530 (description, key); Howes & Crimmen 1990: 192– 201 (description, key).

Material examined. MHNUSC 25007- 1, 370 mm TL, 23th August 2010, Galicia Bank; 42º32.846'N — 11º59.027'W; 1,185–1,187 m depth.

Description. Body elongated and attenuated to the caudal peduncle; head large, 6 times in total length; snout blunt, 4.1 times into head; mouth large and terminal, jaws do not reaching the posterior margin of the orbit; snout as long as eye diameter and 4.1 times into head length; chin barbel absent; only first ventral ray slightly produced, 0.8 in the head length. The main morphometric and meristic characteristics are presented in Table 6 .

Habitat and distribution. Benthopelagic in tropical and subtropical Atlantic at depths between 450 and 2,650 m, but generally from 700 to 1,400 m ( Marshall & Iwamoto, 1973). Amphi-Atlantic distribution; in western Atlantic from the Gulf of Mexico, Caribbean sea and off Suriname and in eastern Atlantic from the Irish continental slope, Azores, Madeira, Canary Islands, Morocco, Mauritania, Guinea-Bissau, Senegal and Gabon (Farran, 1924; Marshall & Iwamoto, 1973; Sobrino et al. 2012). The records from South Africa were not included because they cannot be verified (Howes & Crimmen, 1990).

Key to species of Bathygadidae from the north-eastern Atlantic Ocean waters (adapted from Iwamoto, 2003)

1a. Chin barbel very small or absent; no elongated fin rays in dorsal and pectoral fins and only slightly elongated in the ventral fin.

................................................................................. Genus Bathygadus ...(2) 1b. Chin barbel long, well developed; elongated fin rays in dorsal, pectoral and ventral fins............. Genus Gadomus ...(4) 2a. Very small barbel present on chin; body integument relatively tough, not readily torn; head bones strong; gill filaments pale.

.................................................................................... Bathygadus macrops 2b. No barbel on chin; body integument weak, easily torn; head bones weak, easily broken; gill filaments dusky or pale....... 3 3a. Pelvic-fin rays 8; gill filaments dusky; interorbital width moderate, 4 or more times into head length.....................

.............................................................................. Bathygadus melanobranchus 3b. Pelvic-fin rays 9; gill filaments pale; interorbital wide, 2.5–3.0 into head length..................... Bathygadus favosus 4a. Two elongated rays in pelvic fin; pectoral-fin soft rays 20 to 28................................... Gadomus arcuatus 4b. One elongated ray in pelvic fin; pectoral-fin soft rays 14 to 21.................................................. 5 5a. Gill rakers on lower limb of first arch 26 to 31; interorbital length 21–28% head length; pectoral-fin soft rays 14 to 18; orbit

17.1–28.0% head length; 9–13 pyloric caeca in adult specimens.................................. Gadomus longifilis 5b. Gill rakers on lower limb of first arch 19 to 21; interorbital length 15.2–20.5% head length; pectoral-fin soft rays 17 to 21; orbit

24.6–31.6% head length; more than 50 pyloric caeca in adult specimens............................. Gadomus dispar

Figures

FIGURE 1. Molecular phylogenetic analysis of bathygadid COI barcoding sequences by Maximum Likelihood method. For each specimen a code followed by a location abbreviation (NEA, Northeast Atlantic) was given. Voucher specimens were deposited in the Museo de Historia Natural da Universidade de Santiago de Compostela (MHNUSC) and Instituto Español de Oceanografía de Canarias (IEOSC). A Gadus morhua sequence (EU 752090) was employed as out-group. The percentage of trees in which the associated taxa clustered together is shown above the branches. The scale bar represents 1 fixed mutation per 10 nucleotide sequence positions.

FIGURE 5. Bathygadus melanobranchus from the north-east Atlantic Ocean, MHNUSC 25007 – 1, 370 mm total length.

Tables

TABLE 6. Comparison of morphometric, meristic data and respective body proportions for specimens of Bathygadus melanobranchus.

Bathygadus melanobranchus	MHNUSC (25007–1)	Parr (1946)	Iwamoto (1970) Marshall & Iwamoto N=22 (1973) N=11
Total Length (mm) Head length (mm) As % TL	370 62	— —	70–400 — — 28–89
Head length As % HL Eye diameter	16.8 24.2	— 27–29	— 15–20 — 24.7–34.2
Preorbital length Postorbital length Interorbital length	24.2 51.6 29.0	— — —	25–33 24.7–29.2 46–52 — 25–35 24.7–33.9
Upper jaw length 1st Predorsal length 2nd Predorsal length	54.8 111.3 151.6	54–57 — —	51–60 46.1–56.5 — 102.3–115.8 — 128.2–147.9
1st Dorsal base length Preanal length	35.5 195.2	40 —	— — — 166.1–187.0