Pontoeciella abyssicola (Scott T. 1893)

Pontoeciella abyssicola (T. Scott, 1894)

?Artotrogus abyssicolus T. Scott, 1894, pp. 128–129, pl. 12: figs. 5–9; pl. 14: figs. 11–18.

Pontoeciella abyssicola (T. Scott).—Giesbrecht, 1895, p. 186; 1899, pp. 20–22, 83, 105, pl. 5: figs. 15–27.—Farran, 1936, pp. 125–126, fig. 24.—Saraswathy, 1967, p. 89, fig. 2 [7–8].

Ratania sp. Rose, 1939, pp. 24–30, figs.

Carnegiella gracilis C. B. Wilson, 1942, p. 176, figs. 20–25.

Danodes plumata C. B. Wilson, 1942, pp. 182–183, figs. 57–68.—Olson, 1949, pp. 51–54, pl. 4: figs. 8–11.

Carnegietta gracilis (C. B. Wilson).—Schmitt, in C. B. Wilson, 1950, pp. viii–ix.

Pontoeciella is close to the Ascomyzontidae, but Pontoeciella has no mandibular palp and fewer segments in female 1st antenna and 1st maxilla.

Giesbrecht (1899) and Farran (1936) have discussed the variable shape of the prosome and irregularities in the armature of the swimming legs of P. abyssicola.

Examination of C. B. Wilson’s type specimens, deposited in the United States National Museum, confirmed Sewell’s (1948) supposition that Carnegietta gracilis (C. B. Wilson, 1942) is the male and Danodes plumata C. B. Wilson, 1942, is the female Pontoeciella abyssicola. Armature is highly variable in this species, and several of Wilson’s illustrations reflect this.

Records indicate a wide distribution and a variable length in female:

Author

Location

Length, mm

Depth, m

Scott (1894) Gulf of Guinea 1.1 450–700

Giesbrecht (1899) Naples 1.5 —

Tropical Eastern Pacific 0.9–1. 17 1000–1800

Farran (1926) Bay of Biscay 1.15 200–750

Farran (1936) Great Barrier Reef 0.7–0. 93 0–580

Rose (1939) Bay of Algiers 1.3 0–200

Wilson (1942) Eastern and Central Pacific 1.25–1.45 0–100

Olson (1949) Baja California Coast 0.90 0–800

Saraswathy (1967) Trivandrum Coast 1.0 —

IPHC Gulf of Alaska 1.65 850–1020

MATERIAL STUDIED.—1 female from sample 4; body length 1.65 mm.

FEMALE.—IPHC specimen and Scott’s (1894) description of female appeared to be similar in most respects; both differ in some details from descriptions of Giesbrecht (1899) and Rose (1939): differences in proportion of urosomal segments; terminal spines of 2nd antenna vary in length and width; mandible straight rather than curved; claw of 2nd maxilla inclined 65° (also shown by Saraswathy, 1967, fig. 2[7]) rather than 90°; leg 3 exopod spines are slightly longer than on Giesbrecht’s and Rose’s illustrations; leg 4 shows differences in spine of exopod 2 and seta of protopod 2. Second maxilla of IPHC specimen with spine and 1st endopod of leg 1 with inner seta as described by Saraswathy (1967).

First maxilla (Figure 27) differs from illustrations of Scott (1894, pl. 14: fig. 14) and Giesbrecht (1899, pl. 5: fig. 22), which resembled each other. First maxilla of IPHC specimen 2-segmented with expanded basal segment. Apex of 2nd segment with 1 long seta arising within demisheathed expanded base of 2nd long, lashlike seta. Small subapical protrusion with short seta.

Leg 4 (Figure 28) showed some minor differences in armature from descriptions given by Scott and Giesbrecht.