Seba gruneri Yerman & Coleman 2009, sp. nov.

Seba gruneri sp. nov.

(Figs 1–3)

Type material. Holotype, male, 3.9 mm, AM P71239, Horseshoe Reef, Lizard Island (14°41.21’S 145°26.49’E), sponge, large coral bommies surrounded by sand and rubble, by hand on scuba, 9 m, C. Serejo, 2 March 2005 (QLD 1760). Paratypes: 7 males from type locality; and 1 female, 2.5 mm, AM P71237, from type locality.

Other material examined. 32 females, 5 juvenile males AM P71237 (QLD 1760); 1 male JDT/LIZ-19; 3 juveniles, 1 male JDT/LIZ-7.

Type locality. Horseshoe Reef, Lizard Island, Queensland, Australia (14°41.21’S 145°26.49’E).

Etymology. Named for the late Professor Dr. Hans Eckhard Gruner, the predecessor of COC at the Natural History Museum in Berlin, to acknowledge his valuable contributions to crustacean research.

Description. Based on male holotype, 3.9 mm, AM P71239.

Head. Head eyes apparently absent. Antenna 1 peduncular article 1 subequal in length to article 2; article 2 length 2.9 x breadth. Maxilla 1 palp 1-articulate. Maxilla 2 with two plates.

Pereon. Gnathopod 1 subchelate; larger than gnathopod 2; coxa with posteroventral corner rounded; propodus thumb absent, palm obtuse, sculptured; dactylus curved. Gnathopod 2 chelate; ischium long, 3.3 x breadth; carpus not lobate, carpus more than 0.6 x length of propodus. Pereopod 3 coxa with posteroventral corner subquadrate to rounded. Pereopod 4 coxa with posteroventral lobe absent. Pereopod 5 basis evenly expanded, margins subparallel; merus expanded, extending 75% along carpus. Pereopod 6 basis evenly expanded, margins subparallel. Pereopod 7 basis broadly expanded, posterior margin evenly convex; merus broadly expanded, extending past distal margin of carpus.

Pleon. Epimeron 2 posteroventral corner acutely produced. Epimeron 3 posteroventral corner subquadrate. Urosomites 2–3 coalesced. Uropod 1 peduncle subequal in length to uropod 2 peduncle; outer ramus subequal in length to inner ramus. Uropod 2 outer ramus subequal in length to inner ramus. Uropod 3 peduncle about half length of ramus. Telson longer than broad, lateral margins slightly convex.

Female (sexually dimorphic characters). Based on paratype, female, 2.5 mm, AM P71237. Antenna 1 peduncular article 2 length 2.5 x breadth. Gnathopod 1 chelate; smooth, straight. Pereopod 5 extending halfway along carpus. Pereopod 7 merus expanded, extending about halfway along carpus.

Habitat. Sponges on large coral bommies surrounded by sand and rubble.

Remarks. Similar to Seba gruneri sp. nov., there are a few sebid species that have a characteristically widened merus lobe that surpasses the distal margin of the carpus on pereopod 7 in the male sex. However, details of the morphology or combination of characters are different. Seba aloe Karaman, 1971, Seba antarctica Walker, 1907 and Seba gloriosae Ledoyer, 1986 have the same merus shape, but on pereopods 5–7 (vs on pereopod 7 only) and a finger like palm process creating a chelate gnathopod 1 (vs a subchelate, sculptured palm). Also similar is the material that Griffiths (1974, 1976) described from Southern Africa as Seba saundersi. This species has a ventrally strongly elongate merus lobe on pereopod 7 (weaker on pereopod 6) and a subchelate, though differently sculptured subchelate palm region. A similar merus lobe arrangement appears in Seba subantarctica Schellenberg, 1931, but this species has a clearly chelate gnathopod 1. Seba chiltoni Moore, 1987 and Seba typica (Chilton, 1884) in the descriptions by Ledoyer, 1978 and 1986 are very similar to the new species in the shape of the gnathopod 1 palm and the protrusion on the inner curvature of the dactylus, but compared to Seba gruneri sp. nov. the merus lobe on pereopod 7 is not longer than the distal carpus margin. Seba robusta Ortiz & Lemaitre, 1997 has also a very similar palm morphology of gnathopod 1, however, the meral lobes are short and rather slender.

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