Amphilochus justi, Azman, 2009

Azman, B. A. R., 2009, Amphilochidae *, Zootaxa 2260 (1), pp. 143-152 : 144-147

Amphilochus justi sp. nov.

( Figs 1 , 2 )

Type material. Holotype, female, 2.6 mm, AM P70575 (in slides), 200 m off Research Beach , Lizard Island (14°40.83’S 145°26.75’E), fine biogenic sand, patches of reef and sand, 2.5 m, J. Just, 23 February 2005 (QLD 1625).

Type locality. Off Research Beach , Lizard Island, Queensland, Australia (14°40.83’S 145°26.75’E) .

Etymology. The species is dedicated to Dr Jean Just from the Museum of Tropical Queensland, who collected these animals.

Description. Based on holotype, female, 2.6 mm, AM P70575.

Head. Head lateral cephalic lobes apically round; eyes irregularly round with black centre bordered with numerous opaque ommatidia. Antenna 1 flagellum with about 5 articles, distoventral corner of last three articles with several elongate and flattened setae; accessory flagellum lacking. Antenna 2 longer than Antenna 1; flagellum with 5 articles. Upper lip bilobed, asymmetric, densely pubescent apically. Lower Lip each lobe of outer plate subtriangular, shoulders densely pubescent, produced inward with bifid tooth. Mandible molar conical; palp with 3 articles of length ratios 6:13:16, article 3 apically attenuated. Maxilla 1 outer plate with several large teeth; palp biarticulate, extending far beyond outer plate, apical margin with several large teeth. Maxilla 2 inner plate with medial row of submarginal setae; outer plate longer than inner, with several terminal setae. Maxilliped inner plate missing; palp article 3 longer than wide, dactylus without unguis.

Pereon. Gnathopod 1 coxa anterodistally rounded; basis slender, anterior and posterior margin without setae, posterodistal margin with seta; merus with 2 distal robust setae; carpus with robust setae on posterior lobe; propodus anterior margin with few long setae, anterodistally with 2 short setae, palm transverse lined with slender setae and defined by three robust setae; dactylus inner margin serrate. Gnathopod 2 basis anterior without seta, with flange, posterodistal margin with robust seta; carpus with elongate posterior lobe extending edge of palm, inner margin of lobe with two robust setae, distal part with three robust setae; propodus distally expanded, palm transverse, serrate, lined with slender setae, posterodistally with 2 short robust setae; dactylus inner margin serrate. Pereopod 3 coxa longer than wide; basis without setae; dactylus attenuate. Pereopod 4 coxa large, quadrate; dactylus attenuate. Pereopod 5 basis expanded, anterior margin with 4 short robust setae, posterior margin with short fine setae; dactylus attenuate. Pereopod 6 basis anterior margin with 4 robust setae, posterior margin expanded with fine setae; dactylus attenuate. Pereopod 7 basis anterior margin with 5 robust setae, posterior margin subquadrate with fine setae along margin; dactylus attenuate.

Pleon. Uropod 1 rami subequal in length with several short robust setae along margin; peduncle elongate much longer than rami, inner margin with 5 short robust setae. Uropod 2 biramous, inner ramus longer than outer ramus with several short robust setae along margin; peduncle subequal in length to inner ramus, inner margin lined with short robust setae. Uropod 3 biramous, rami subequal, inner ramus slightly longer than outer; peduncle longer than rami, lined with short robust setae. Telson entire, longer than wide, rounded distally.

Male (sexually dimorphic characters). Unknown.

Habitat. Sandy biogenic substrate.

Remarks. In general appearance this species shows close resemblance to species of Amphilochus as is particularly evident in the shape of the gnathopods, coxae, uropods and telson. However, the heavily setose peduncular article of uropod 2, subquadrate structure of pereopod 7 basis, and comparatively longer carpal lobe of gnathopod 2 (exceeding the end of propodus) are quite unlike those of any other known species of Australian Amphilochus . Amphilochus justi sp. nov. is quite similar to A. ruperti Moore, 1988 , in not having a dactylar unguis on the maxillipedal palp. On the other hand it differs in the absence of accessory flagellum of antenna 1, longer carpal lobe of gnathopod 2 (extending beyond edge of palm) and the absence of submarginal minute robust setae along the anterior margins of the bases of pereopods 5–7. The other known Australian Amphilochus , A. marionis Stebbing, 1888 , could be readily distinguished from A. justi sp. nov. by having propodus of gnathopod 2 as long as wide and a relatively shorter telson. Table 1 summarizes the characters and states reviewed from literature and the present study.

Distribution. Australia. Queensland: Lizard Island (current study).

Figures

FIGURE 1. Amphilochus justi sp. nov., holotype female, 2.6 mm, AM P70575, off Research Beach, Lizard Island, Great Barrier Reef.

FIGURE 2. Amphilochus justi sp. nov., holotype female, 2.6 mm, AM P70575, off Research Beach, Lizard Island, Great Barrier Reef.