Metataeniacanthus epigri Cressey & Cressey 1979

Metataeniacanthus epigri

MATERIAL EXAMINED.—Holotype (USNM 171313) and 28 paratypes (USNM 171314) from the gills of Synodus englemani Schultz (paratypes USNM 152981) collected at Bikini, 8 July 1946. Seven collections containing 27 from the Red Sea near Aquaba. A single collection containing 1 from off Zanzibar. A single collection containing 3 from the Comores Islands. Two collections containing 9 from Nossi Bè, Malagasy Republic. Four collections containing 12 and 1 from Caragados Islands. Twenty three collections containing 236 and 3 from the Seychelles. Two collections containing 11 from off Male, Maldive Islands. One collection containing 2 from the South China Sea off Viet Nam. Seven collections containing 17 from Big Hope Island and Endeavour Reef off Australia. Two collections containing 55 from off the Philippines. Two collections containing 4 from Indonesia. Three collections containing 24 from near Trobriand Islands, New Guinea. Three collections containing 36 from off New Britain. Three collections containing 6 from off Ambon Island. One collection containing 75 and 1 from Celebes. Two collections containing 5 from the Solomon Islands. Two collections containing 3 and 1 from the Marianas Islands. Four collections (exclusive of types) containing 68 from the Marshall Islands. Three collections containing 14 from Palau Islands. One collection containing 7 from Tonga Islands. One collection containing 1 from Fiji. One collection containing 1 from Samoa. One collection containing 4 from Tahiti. One collection containing 2 from Gambier Islands. All above collections from the gill filaments of Synodus englemani.

Female: Body form as in Figure 8a. Total length 1.94 mm, greatest width 0.42 mm (measured at widest part of cephalon). Cephalon wider than long (0.34 × 0.42 mm) with low rounded rostrum. Genital segment and area of egg sac attachment (Figure 8b) wider than long (118 × 230 μm), not distinctly separated from abdomen and seen as a prominent ventral projection when viewed laterally. Abdomen almost half body length (0.94 mm), unsegmented, cylindrical, tapering gradually, with fine spinules near base of caudal rami (Figure 8c). Caudal rami (Figure 8c) almost 3 times as long as wide (94 × 32 μm), each ramus with 6 setae, innermost terminal finely plumose, longest 324 μm.

First antenna (Figure 8d) 7–segmented with aesthete on last 2 segments; segments measure 83, 68, 24, 24, 32, 24, and 35 μm long respectively, basal segments with 25 plumose setae. Second antenna (Figure 8e) 3–segmented, armed essentially as in other species. Oral area as in Figure 8f; labrum with fine spinules along posterior edge, mandible similar to other species, paragnath conspicuously trilobed and bearing row of spinules, remaining mouth parts as in other species. Maxilliped (Figure 8g) claw not reaching to base of setae on basal segment.

Legs 1–4 biramous, rami 3–segmented. Leg 1 (Figure 9a) basipod with stout plumose seta on outer corner and longer plumose seta on inner edge near interpodal plate; exopod 3–segmented, first segment with a seta on outer distal corner, second with a seta on outer and one on inner edge, last segment with 7 setae; endopod first segment with inner seta (segment indistinctly separated from basipod), second segment with an inner seta, last segment with 7 setae (outer 2 much shorter than other 5). Leg 2 (Figure 9b) basipod with naked seta on outer distal corner; exopod first segment with long, slender, finely spinulose spine on outer distal corner, inner edge with thick hairs, second segment with 2 blunt sensillae near base of outer spine and 1 inner seta, last segment with a pair of blunt sensillae near base of each of the 3 outer spines (Figure 9c) and terminal to inner edge with 5 finely plumose setae; endopod first segment outer edge fringed with hairs and one seta on inner edge, second segment outer edge with hairs and inner edge with hairs and one seta, last segment with 3 outer spines (proximal 2 about 1/2 length of distalmost) each with hyaline fringe on distal half of outer margin, terminal to inner margin of segment with 3 finely plumose setae plus hairs on inner margin. Leg 3 (Figure 9d) similar to leg 2 except exopod second segment more elongate and endopod last segment with one less seta. Leg 4 (Figure 10a) basipod with naked seta on outer distal corner; exopod first segment with long outer recurved spinulose spine and inner edge with hairs, second segment with short slender outer spine and one inner seta, last segment with 4 outer to terminal slender, spinulose spines and 3 inner finely plumose setae; endopod first and second segments outer edges with hairs and one long finely plumose seta on inner edge of each, last segment outer edge with few hairs, 2 short outer finely spinulose spines and one long terminal seta (distal half finely spinulose). Leg 5 (Figure 10b) basal segment with naked dorsal seta, last segment with 4 finely spinulose seta (innermost considerably longer than others). Leg 6 (see Figure 8b) represented by 3 naked setae at area of egg sac attachment.

Eggs sacs cylindrical, extending entire length of abdomen.

Male: Body form as in Figure 10c. Total length 0.96 mm, greatest width 0.37 mm. Cephalon somewhat wider than long (0.37 × 0.30 mm). Genital segment (Figure 10d) slightly longer than wide (153 × 142 μm). Abdomen (see Figure 10c) 3–segmented; segments wider than long, measuring 59 × 89 μm, 47 × 74 μm, and 38 × 59 μm, respectively. First abdominal segment with lateral lobate processes anteriorly. Caudal rami (Figure 10e) longer than wide (56 × 24 μm) each ramus bearing one lateral, 2 subterminal and 3 terminal setae (longest 236 μm).

Rostrum (Figure 10f) with ventral sclerotized plate bearing anteriorly directed spinelike process. Cephalic appendages as in female except maxilliped. Maxilliped (Figure 10g) second segment with saddle-shaped process on inner margin, edges of process ornamented with rows of spinules, 2 setae on inner margin of second segment; claw with heavily serrate inner margin, tip somewhat expanded and serrate as indicated in the figure.

Legs 1–4 similar to female except exopods lack sensillae at bases of outer spines and exopod segments relatively shorter. Leg 2 illustrated by Figure 10h. Leg 5 basically as in female, innermost terminal seta broken off on both specimens. Leg 6 absent.

ETYMOLOGY.—The Latin epigri (“wooden peg”) alludes to the sensillae at the bases of the outer exopod spines of female legs 2 and 3.

Bikini, Marshall Islands; Red Sea; Zanzibar; Comores Islands; Nossi Be, Madagascar; Caragados Islands; Seychelles; off Male, Maldive Islands; South China Sea off Viet Nam; Big Hope Island and Endeavour Reef off Australia; Philippines; Indonesia; New Guinea; New Britain; Ambon Island; Celebes; Solomon Islands; Mariana Islands; Marshall Islands; Palau Islands; Tonga Islands; Tahiti; Gambier Islands