Ericthonius pugnax Dana, 1852

Just, Jean, 2009, Ischyroceridae *, Zootaxa 2260 (1), pp. 463-486 : 478-481

Ericthonius pugnax Dana, 1852

( Figs 10 , 11 )

Ericthonius pugnax Dana, 1852: 218 .

Ericthonius pugnax . — Moore, 1988: 727, fig. 14. — Myers, 1995: 80, figs 40–42.

For synonymy and further list of records see Moore, 1988: 727, 729.

Material examined. Sixty one specimens in all. 1 male, 4 females, AM P70661 (QLD 1639) ; 1 male, 2 females, AM P70700 (QLD 1640); female (illustrated), 4.8 mm, AM P70755 (QLD 1645) ; 3 males, 3 females, AM P70719 (QLD 1645) ; 4 males, 2 ovigerous females, 2 juveniles, 3 broken specimens, AM P70738 (QLD 1645) ; 4 males, 6 females, AM P75647 (QLD 1645) ; 1 male, 1 female, AM P70731 (QLD 1648) ; 2 females, AM P70850 (QLD 1666) ; 2 males, 1 female, AM P70961 (QLD 1687); 1 ovigerous female, AM P70955 (QLD 1697) ; 2 males, 2 females, 1 juvenile, AM P71299 (QLD 1716) ; 2 juvenile, AM P71284 (QLD 1763) ; 1 male (illustrated), 3.7 mm, AM P71267 (QLD 1771) ; 5 males, 2 females, AM P75648 (QLD 1771) ; 1 male, broken, 1 female, AM P75649 (QLD 1823) .

Type locality. Sulu Sea , Indonesia .

Description. Based on male, 3.7 mm, AM P71267, and male, 3.4 mm, AM P75648.

Head. E yes 1/3 dorsal length of head, situated mainly within lateral lobe of head. Antenna 1 peduncular article 1 distinctly shorter than article 3; flagellum distinctly longer than peduncular article 3, with 10 articles, most with single aesthetasc. Antenna 2 only slightly longer than 1, peduncular articles 4 and 5 with 4–5 rows of setae; flagellum distinctly longer than peduncular article 5, with 10 articles.

Pereon. Coxae 1–4 not ventrally setose. Gnathopod 1 distinctly smaller than gnathopod 2; coxa about 2/3 length and half width of coxa 2; carpus distinctly longer than propodus; propodus length 1.5 width, posterodistal margin evenly rounded. Gnathopod 2 carpochelate; coxa 2 widely separated from coxa 1 and 3, rounded, distinctly broader than deep, with stridulation ridges along ventral margin; basis widening distally, length approximately 2.5 width; carpus with distinct free posterior expansion with two carpal teeth, posterior margin of carpus with slender setae only; propodus length 3/4 carpus length, rectangular, posterior margin with low rectangular projection in distal 2/3; dactylus as long as propodus, with apical tuft of long setae. Pereopods 3–4 basis distally expanded, flask shaped; merus weakly expanded. Pereopods 5 coxa with a few short slender setae along ventral margin, basis with distinctive posterodistal tongue-shaped lobe overreaching ischium. Pereopod 7 basis length 1.5 width.

Pleon. Uropod 1 peduncle dorsolateral margin with row of 3–4 robust setae, outer ramus with 2 lateral and 1 medial robust setae, inner ramus with 2 robust setae on medial margin. Uropod 2 peduncle dorsolateral margin with 1 or 2 robust setae, medial margin with single long robust seta distally; outer ramus without lateral or medial robust setae; inner ramus lateral margin without setae, medial margin with single robust seta. Uropod 3 peduncle length approximately twice greatest width, broad proximally, narrowing distally, with 2 dorsolateral slender setae; ramus length approximately twice width.

Female (sexually dimorphic characters). Based on female, 4.8 mm, AM P70755. Similar to male, except for sexually dimorphic gnathopod 2. Females share with males stridulation ridges on coxa 2, but lack the tongue-shaped posterior lobe on basis pereopod 5.

Habitat. Seagrass beds and blue-green algae; sediment among coral rubble; 1–11 m depth, Lizard Island; to 200 m depth elsewhere.

Remarks. Ericthonius pugnax males are easily distinguished from its congeners by the tongue-like posterior lobe on the basis of the male pereopod 5. The Lizard Island material is most similar to specimens of E. pugnax from Madang, Papua New Guinea, illustrated by Myers (1995: 80, fig. 40), especially in the shape of the posterior margin of gnathopod 2 propodus. Hyperadult males of E. pugnax were not present in the material studied.

Distribution. Australia. Lizard Island (current study). Ericthonius pugnax is widely distributed in the Indo-West Pacific tropical to temperate waters from Madagascar north-and eastward to Japan and south to New Zealand (see map of distribution in Hirayama 1985, fig. 160). More recently the species has been reported from Western Australia ( Moore 1988) and Papua New Guinea ( Myers 1995).

Figures

FIGURE 10. Ericthonius pugnax Dana, 1852, male, 3.7 mm, AM P71267, except M1, male, 3.4 mm, AM P75648, Casuarina Beach, Lizard Island, Great Barrier Reef. Gnathopods 1–2 (not to scale).

FIGURE 11. Ericthonius pugnax Dana, 1852, male, 3.7 mm, AM P71267, except F, female, 4.8 mm, AM P70755, Casuarina Beach, Lizard Island, Great Barrier Reef.