Polycheria goanna, Myers & LeCroy, 2009

Myers, Alan A., 2009, Dexaminidae *, Zootaxa 2260 (1), pp. 393-424 : 420-423

Polycheria goanna sp. nov.

( Figs 21 , 22 )

Type Material. Holotype, male, 4.0 mm, AM P78023, south of Lizard Head , Lizard Island (~ 14°41’S 145°28’E), coral rubble, 2 m, J.D. Thomas, 29 January 1989 ( JDT / LIZ 14 ) . Paratypes, 2 males, 2 females, AM P78024 , off southern tip of island, Lizard Island , coral rubble and algal turf on patch reef, 1 m, J.D. Thomas, 23 January 1989 ( JDT / LIZ 3 ) .

Type Locality. South of Lizard Head , Lizard Island, Queensland, Australia (~ 14°41’S 145°28’E) .

Etymology. The specific epithet refers to the large monitor lizards or goannas for which the type locality at Lizard Head and Lizard Island itself are named.

Description. Based on holotype, male, 4.0 mm, AM P78023 (JDT/LIZ 14); 2 paratype, males, 3.0– 3.4 mm, AM P78024 (JDT/LIZ 3).

Head. Head eye large, approximately one-half length of head, or huge, nearly as long as head. Antennae 1–2 flagellar articles with very long distal setae, setae 2–3 articles in length. Antenna 2 peduncle article 4 with sparse short bristle setae on anterior margin. Mandible palp absent. Maxilla 1 palp stout, about three times as long as broad, expanded distally, with apical serrations, without marginal slender setae; inner plate with apical seta. Maxilla 2 inner plate subequal to outer plate in length, with dense apical slender setae, inner margin with dense row of slender setae. Maxilliped palp 4-articulate, article 4 reduced, subtriangular, with apical nail.

Pereon. Gnathopods 1–2 coxa anterodistal corner unproduced or weakly produced, rounded. Gnathopod 1 coxa as wide as deep or wider than deep. Pereopods 3–7 fully prehensile. Pereopod 3 coxa anterodistal corner strongly produced, forming subacute process, process moderately slender. Pereopod 4 coxa anterodistal corner strongly produced, forming subacute process, process stout. Pereopod 5 coxa subtriangular, broadest proximally. Pereopods 5–7 of uniform morphology. Pereopod 7 coxa posterodistal corner unproduced or weakly produced, rounded; coxal gill present; carpus subequal in length to propodus.

Pleon. Epimeron 3 with posteroventral spine, ventral margin with elongate slender setae. Urosomite 1 with poorly developed, apically rounded dorsal keel. Urosomites 2–3 fused. Uropod 1 peduncle without slender setae on ventral margin; inner ramus subequal in length to outer. Uropod 2 inner ramus longer than outer. Uropod 3 rami slender, lanceolate, margins with short robust setae; inner ramus longer than outer. Telson subtriangular, broadest proximally, with 1–3 submarginal short robust setae laterally, without apical or subapical robust setae.

Female (sexually dimorphic characters). Based on 2 paratype, females, 2.1–2.6 mm, AM P78024. Eye small, approximately one-third length of head. Antenna 2 peduncle article 4 without short bristle setae on anterior margin. Gnathopod 1 coxa deeper than wide. Pereopod 4 coxa anterodistal process moderately slender. Uropod 2 inner ramus subequal to outer in length.

Habitat. Coral rubble and algal turf on patch reefs at depths of 1– 2 m.

Remarks. Polycheria goanna sp. nov. can be distinguished from all other known species of Polycheria except P. obtusa J.L. Barnard, 1972b from New Zealand by the extremely elongate setae on the flagella of antennae 1–2. It is otherwise very different from that species, however, differing in the distally expanded, poorly setose palp of maxilla 1 (palp distally narrowing, with long marginal and apical slender setae in P. obtusa ), the more strongly produced anterodistal corners of the coxae, the more slender pereopods, the lack of slender setae on the ventral margin of the peduncle of uropod 1 and the inner ramus of uropod 3 ( P. obtusa has long slender setae on these appendages), and the more weakly spinose uropods and telson. It is very similar to P. atolli Walker, 1905 , differing mainly in the longer antennal setae (short in P. atolli ), the presence of an apical seta on the inner plate of maxilla 1 (seta lacking in P. atolli ) and the much less well developed dorsal keel on urosomite 1. The shape of the apical article of the maxillipedal palp may also differ between the two species. Walker's (1905) figure shows a claw-like apical article; however, Ledoyer's (1972, 1983) figures of P. atolli material from Madagascar show a shorter, subtriangular article much closer to that of P. goanna sp. nov. in morphology.

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

Figures

FIGURE 21. Polycheria goanna sp. nov., paratype, male, 2.9 mm, AM P78024, off southern tip of Lizard Island, Great Barrier Reef.

FIGURE 22. Polycheria goanna sp. nov., paratype, male, 2.9 mm, paratype, male 2, 3.4 mm, paratype, female, 2.6 mm, AM P78024, off southern tip of Lizard Island, Great Barrier Reef; holotype, male 3, 4.0 mm, AM P78023, south of Lizard Head, Lizard Island, Great Barrier Reef.