Autonoe seurati ( Chevreux, 1907 ) Myers, Alan A., 2009

Myers, Alan A., 2009, Aoridae *, Zootaxa 2260 (1), pp. 220-278 : 226-227

Autonoe seurati ( Chevreux, 1907) , nov. comb.

( Figs 5 , 6 )

Xenocheira seurati Chevreux, 1907: 416 . — Chevreux, 1908: 510, figs 26–28. — Schellenberg, 1938 b: 86. — Ledoyer, 1984: 41, fig. 19. — Moore, 1988: 712, figs 4–7. — Lowry & Stoddart, 2003: 73 (catalogue).

Material examined. 1 male, 1 female, AM P70696 (QLD 1640) ; 1 male, AM P70728, (QLD 1640) ; 2 males, 4 females, AM P70751 (QLD 1645) ; 2 males, AM P70724, (QLD 1646) ; 2 males, 2 females, AM P70739 (QLD 1647); 2 unsexed, AM P75573 (QLD 1863); 7 unsexed, AM P75673 (QLD 1878); 4 unsexed, AM P75672 (QLD 1895); 2 unsexed, AM P 75674 (QLD 1902); 1 unsexed, AM P75676 (QLD 1903); 2 unsexed, AM P75574 (QLD 1905); 1 unsexed, AM P75675 (QLD 1927); 4 unsexed, AM P75579 (QLD 1927) .

Type locality. Mangareva Island , Gambier Islands, French Polynesia (~ 23°5'57''S 134°58'1''W) .

Description. Based on male, 3.0 mm, AM P70739.

Head. Head lateral cephalic lobes apically round. Antenna 1 flagellum with about 12 articles; accessory flagellum with one long and one distal rudimentary article. Antenna 2 with few long setae. Lower lip with fine setae only. Maxilla 1 inner plate with 1 long pectinate apical seta. Mandible, palp article 3 longer than 2, posterior margin straight or weakly falcate, posterior margin with setae of more than two distinct lengths.

Pereon. Pereonites without sternal spines. Gnathopod 1 enlarged in both sexes; coxa weakly produced anterodistally; basis robust, half or more as broad as long, without a spine, posterodistal margin with setae absent, anterodistal margin with strong flange, densely covered in long setae; ischium anterior margin without flange, posterodistal margin with long setae; merus not elongated, fused along its entire length with carpus, posterior margin with dense rows of setae, without posterodistal spine; carpus subequal in length with propodus, anterior margin with long setae, without spine, with an oblique row of long setae on inner face, posterior margin without spines; propodus anterior margin with long setae, posterior margin straight, palm present, sinuous, delimited from posterior margin, by subquadrate corner, with robust seta defining palm, without spine near base of dactylus; dactylus about half length of propodus, fitting palm. Gnathopod 2 subchelate; basis anterodistal margin convex, without flange, with dense long setae, posterodistal margin without robust setae; merus enlarged elongate, anterodistal margin with dense long setae; carpus subequal with propodus, anterior margin lobate, with long dense setae; propodus anterior margin with long dense setae, without robust seta or spine defining palm. Pereopod 3 without brush of long setae on merus. Pereopod 5 basis enlarged, posterodistal and anteroproximal margins with short robust setae. Pereopod 6 basis not or weakly produced posterodistally. Pereopod 7 significantly greater than 125% length of pereopod 6.

Pleon. Epimeron 3 posterodistal margin rounded. Uropod 1 rami subequal, peduncle much longer than broad, distoventral spine about half length of peduncle. Uropod 2 biramous, endopod longer than exopod, peduncle with distoventral spine over two thirds length of peduncle. Uropod 3 biramous, rami subequal, inner ramus 1.5 x length of peduncle. Telson with distal fine setae only.

Female (sexually dimorphic characters). Based on female, 3.0 mm, AM P70739. Gnathopod 1 carpus and propodus a little more slender than those of male; propodus palm evenly rounded; dactylus overlapping palm.

Habitat. Udotea over sand, seagrass, rubble, oyster shells.

Remarks. Autonoe seurati presents all the diagnostic features of the genus Autonoe Boeck, 1871 . These are: mandibular palp posterodistal margin concave and with setae of more than two distinct lengths; male gnathopod 1 carpus subequal with propodus; uropod 3 peduncle moderately elongate, rami with marginal spines and no marginal setae. Autonoe resembles Lemboides Stebbing, 1895 ,but differs in the unshortened peduncle of uropod 3 and in having the male gnathopod 1 carpus subequal with the propodus. The genus Autonoe was, until now, considered to be restricted to the Atlantic Ocean (Myers, 1988). Its occurrence in Australian waters is therefore most unexpected, but the combination of characters is thought unlikely to be a homoplasy. The elongate, highly setose, filtering gnathopod 2 occurs as a convergent evolution in many aorid genera, viz Bemlos ( B. leptocheirus Walker, 1909 ), Microdeutopus ( M. versiculatus Bate, 1857 ), Lemboides ( L. angusticarpa Lyons & Myers, 1990 ). Within the Great Barrier Reef, A. seurati is easily recognised by its elongate, filtering (setose) gnathopod 2 in both sexes.

Distribution. Australia. Queensland: Lizard Island (current study); Western Australia ( Moore 1988). Gambier Islands ( Chevreux 1907). Fiji. Viti Levu ( Schellenberg 1938). New Caledonia. Noumea ( Ledoyer 1984).

Figures

FIGURE 5. Autonoe seurati Chevreux, 1907, male, 3.0 mm, AM P70696, Watsons Bay, Lizard Island, Great Barrier Reef.

FIGURE 6. Autonoe seurati Chevreux, 1907, male, 3.0 mm, female 3.2 mm, AM P70696, Watsons Bay, Lizard Island, Great Barrier Reef.