Gigantactis microdontis Bertelsen, Pietsch, and Lavenberg, 1981

Prokofiev, Artem M. & Pietsch, Theodore W., 2019, First Record of the Ceratioid Anglerfish Species Gigantactis microdontis (Teleostei: Lophiiformes: Gigantactinidae) in the Western Pacific Ocean, Zootaxa 4664 (3), pp. 441-444 : 441-443

Gigantactis microdontis Bertelsen, Pietsch, and Lavenberg, 1981 ( Figs. 1 , 2 )

Gigantactis sp. 2: Parin et al., 1973: 146 (19.5-mm metamorphosal stage; eastern tropical Pacific, 12° 30’ S, 87°45’ W, 0–100 m); Parin et al., 1977: 156 (107 mm SL, western tropical Pacific Ocean, 7° 57’ N, 135° 53’ E, 0–1000 m).

Gigantactis microdontis Bertelsen et al., 1981: 54 , figs. 56–58, 67 (original description, seven specimens, 19.5–127 mm SL, eastern Pacific); Bertelsen and Pietsch, 2002: 959, 961, fig. 3D (comparison with congeners, in key); Love et al., 2005: 62 (eastern North Pacific); Walther-Mendoza et al., 2013: 413, tabl. 1 (in list, LACM 30284, 32204, off Guadalupe Island).

Material. IOM 3596 , female ( Fig. 1A ), 110 mm SL, western tropical Pacific Ocean , 7° 57’ N, 135° 53’ E, Isaacs-Kidd midwater trawl no. 87, fished open between 0–1000 m, 3300 m wire out, 5:42–6:42 hours, R/ V Vityaz, cruise 57, station 7297, sample no. 199, 29 March 1975.

Description. Illicium without lateral filaments, nearly cylindrical throughout length; escal bulb ( Fig. 1B ) clubshaped, without dermal spinules, pigmented only near base and on distal part of short distal prolongation; distal patch of pigment oblong in shape, tapering posteriorly towards pore of photophore; 13 unpigmented stalked filaments, arising from distal surface of bulb just inside edge of distal pigment patch in two nearly parallel, lateral series that meet anteriorly; escal filaments short, length approximately equal to diameter of bulb, spatulate and compressed distally.

Dorsal-fin rays 5, anal-fin rays 5, pectoral-fin rays 16, caudal-fin rays 9, free nearly to base. Number of premaxillary teeth 20; number of dentary teeth 31. Measurements in percent of SL: illicial length 245.5, length of esca (excluding distal filaments) 6.4, caudal peduncle length 32.7, longest caudal-fin rays (second and seventh) 37.3, longest dentary and premaxillary tooth 0.7 and 0.9, respectively.

Remarks. Parin et al. (1977: 156) measured SL of 107 mm for this specimen; however, we measured 110 mm from the tip of the pterygiophore of the illicium to the posteriormost margin of the hypural plate. It may reflect a different scheme of measurements.

Figures

FIGURE 1. Gigantactis microdontis: (A) IOM 3596, 110 mm SL, habitus; (B) IOM 3596, esca, lateral view, scale bar—2 mm; (C) esca of the 66-mm SL holotype, MCZ 52574, drawn by K. Elsman, after Bertelsen & Pietsch (2002: fig. 3D), scale bar—1 mm.

FIGURE 2. Known distribution of Gigantactis microdontis: (○) previous records, (●) new record. A single symbol may indicate more than one capture.