Icilius ovalis Dana, 1852

Watson, M. J., Lowry, J. K. & Steinberg, P. D., 2004, Revision Of The Iciliidae (Crustacea: Amphipoda), Raffles Bulletin of Zoology 52 (2), pp. 467-495 : 485-486

Icilius ovalis Dana, 1852

Icilius ovalis Dana, 1852a: 844 pl. 212, fig 4; 1852b: 220; Della Valle, 1893: 345 (part); Stebbing, 1906: 707 (part); 1910: 625.

Icilius ellipticus Dana, 1853: 844 , pl. 56, fig. 4a-g; Della Valle, 1893: 345 (part); Stebbing, 1906: 707 (part).

Type material. – Lost.

Material examined. – The figures of Dana, 1852a.

Type locality. – Balabac Strait , Northern Borneo .

Description. – Head length 2.6 x width; rostrum subacute. Antenna 1 shorter than antenna 2; peduncular article 1 longer than, (1.33 x) article 2; flagellum 19+ articles. Mandible left incisor with 3 serrations; accessory setal rows: left with 7– 8 setae; palp article 2 broad, length 4.4 x breadth, 1.1 x article 3; article 3 slender, straight, not distally falcate. Maxilla 1 inner plate with 3 apical pappose setae; outer plate with 11 setal-teeth; palp with 8 apical robust setae and many subapical slender setae.

Pereon. Pereonite 7: posterodorsal margin with mid dorsal spine, without setae along posterior margin. Gnathopods 1 and 2 not sexually dimorphic. Pereopods 3-4: basis with midmedial row of vertical pappose setae, with submarginal row of robust setae, with marginal row of pappose setae. Pereopod 5: Unknown. Pereopod 6: Unknown. Pereopod 7: basis with posterodorsal corner bicuspidate, outer cusp much longer than inner.

Pleon. Pleonite 1: posterodorsal margin: with mid dorsal spine, without setae along posterior margin; posterolateral margins: without spines. Pleonite 2: with mid dorsal spine, without setae along posterior margin; posterolateral margin without spines. Pleonite 3: smooth, without spines or bulges, without setae along posterior margin. Urosomite 1: short, less than 2 x length of urosomite 2. Uropod 3: rami unknown. Telson : longer than broad, tapering distally.

Habitat. – Coralline algae.

Remarks. – Dana appears to have mentioned I. ovalis for the first time in 1849, and then published a description ( Dana, 1853) under the name I. ellipticus . It appears that the second name has not been used since 1853.

Icilius ovalis is a poorly described species. This is unfortunate because it is the type species of the genus. We tried to recollect this species in Sabah in Dec. of 1998, but the areas where we were able to dive, Tunku Abdul Rahman National Park, were so degraded that there was little chance of the host or the species being present.

Icilius ovalis appears to be a basal taxon with no clear sister species. It is the only Icilius with a spine on the posterodorsal margin of pleonite 3. It shares a broad mandibular palp with I. crinocolus , I. pulchellus and I. punctatus , but this may be a homoplasy. It has a mid-dorsal spine on the posterior margin of pleonite 1, a character it shares with I. caledoniana , I. crinocolus and I. danae , a mid-dorsal spine on the posterior margin of pleonite 2, a character it shares with I. caledoniana , I. crinocolus and I. danae and I. pulchellus .

Distribution. – Balabac Strait, Northern Borneo.