Aoroides palfreyensis, Myers, 2009

Myers, Alan A., 2009, Aoridae *, Zootaxa 2260 (1), pp. 220-278 : 221-223

Aoroides palfreyensis sp. nov.

( Figs 1 , 2 )

Aoroides vitiosus . — Myers, 2005: 355 (not A. vitiosus Myers, 1995: 27 , figs 1, 2).

Type material. Holotype, male, 1.8 mm, AM P75478, rubble zone on south-east side of Palfrey Island , Lizard Island (14°41'S 145°27'E), heavy algal turf, fine sediment, rubble on sandy substrate, 1 m, J.D. Thomas, 4 February 1989 (JDT/LIZ 20) . Paratype: female, AM P75479, same station data .

Additional material examined. 1 male, 1 female, AM P77553 (JDT/LIZ 20) .

Type locality. Palfrey Island , Lizard Island, Queensland, Australia (14°41'S 145°27'E) .

Etymology. Named after the type locality.

Description. Based on holotype, male, 1.8 mm, AM P75478.

Head. Head lateral cephalic lobes apically round. Antenna 1 flagellum with about 11 articles; accessory flagellum absent. Antenna 2 with few long setae. Lower lip with fine setae only. Maxilla 1 inner plate with 1 long pectinate apical seta. Mandible, palp absent.

Pereon. Pereonites without sternal spines. Gnathopod 1 enlarged in males only; coxa anterodistally rounded; basis slender, much less than half as broad as long, without a spine, posterodistal margin with setae absent, anterodistal margin with strong acute flange; ischium anterior margin with strong flange, posterodistal margin with few setae; merus elongated as long as or longer than carpus, distally free and produced along posterior margin of carpus, posterior margin with few setae, without posterodistal spine; carpus longer than propodus, anterior margin without setae, without spine, posterior margin without spines; propodus anterior margin with few long setae, posterior margin sinuous, palm absent; dactylus subequal in length with propodus. Gnathopod 2 subchelate; basis anterodistal margin weakly concave, without flange, posterodistal margin without robust setae; merus not enlarged; carpus subequal in length with propodus, anterior margin not lobate, with short, sparse setae; propodus anterior margin with short sparse setae, with robust seta defining palm. Pereopod 3 without brush of long setae on merus. Pereopod 6 basis not produced posterodistally. Pereopod 7 about 125% length of pereopod 6.

Pleon. Epimeron 3 posterodistal margin rounded. Uropod 1 rami subequal, peduncle much longer than broad, distoventral spine shorter than peduncle. Uropod 2 biramous, inner ramus longer than outer ramus, peduncle without distoventral spine. Uropod 3 biramous, rami subequal, inner ramus a little shorter than peduncle. Telson with distal fine setae only.

Female (sexually dimorphic characters). Based on paratype, female, AM P75479. Gnathopod 1 merus not greatly elongated, not distally free; carpus shorter than that of male, shorter than propodus. Gnathopod 2 more slender than that of male, basis anterior margin straight, carpus and propodus subequal .

Habitat. Algal turf and rubble on a sandy substrate.

Remarks. This species is very close to Aoroides vitiosus Myers, 1995 from Papua New Guinea, which also lacks a mandibular palp. Myers (1995) gave reasons for retaining the genus Aoroides for species of this genus lacking a mandibular palp. The loss of a palp probably occurs by a single point mutation rather then by gradual loss. There are no other generic level differences between species with and those without a mandibular palp. It differs from A. vitiosus in the acute ending anterodistal flange on the basis of the male gnathopod 1 (rounded in A. vitiosus ) and in the shape of the merus of the male gnathopod 1 which in A. vitiosus , is much shorter than the carpus and constricted at the base of its free portion, whereas in A. palfreyensis , it is longer than the carpus, and evenly tapering. Other differences are the evenly curved posterior margin of the carpus of the male gnathopod 2 in A. palfreyensis (straight in A. vitiosus ) and the shorter carpus of the female gnathopod 1 in A. palfreyensis . The pereopods and the uropods are more slender in A. vitiosus than they are in A. palfreyensis .

Distribution. Australia. Queensland: Lizard Island (current study). Society Islands. Austral Isles ( Myers 2005).

Figures

FIGURE 1. Aoroides palfreyensis sp. nov., holotype, male, 1.8 mm, AM P75478, Palfrey Island, Lizard Island, Great Barrier Reef.

FIGURE 2. Aoroides palfreyensis sp. nov., holotype, male, 1.8 mm, AM P75478, paratype female, 1.8 mm, AM P75479, Palfrey Island, Lizard Island, Great Barrier Reef.