Tepidopleustes acromatius, Just, 2009

Just, Jean, 2009, Pleustidae *, Zootaxa 2260 (1), pp. 836-840 : 837-838

Tepidopleustes acromatius sp. nov.

( Figs 1 , 2 )

Type material. Holotype, male, 3.9 mm (tip of rostrum to insertion of telson), AM P71533, Yonge Reef, Half Mile Opening (14°34'19"S 145°36'51"E), Halimeda opuntia (green coralline algae), 10 m, I. Takeuchi, R. T. Springthorpe & O. Coleman, 5 March 2005 (QLD 1823) . Paratypes: 2 unsexed (poor), AM P71494 (QLD 1819); 1 ovigerous female, 3 fully developed females , 2 males, 6 juveniles, AM P77856 (QLD 1823) ; 2 juveniles (poor), AM P71559 (QLD 1823) ; 1 male, 1 juvenile, AM P71478 (QLD 1823) .

Type Locality. Half Mile Opening , Yonge Reef, Queensland, Australia (14°34'19"S 145°36'51"E) .

Etymology. The epithet is composed of the Greek ακρο (akro) meaning extreme and µάτƖ (mati) meaning eye, in allusion to the very large eyes of this species.

Description. Based on holotype, male, 3.9 mm, AM P71533 and paratype, male, AM P77856.

Head. Rostrum about 0.3 x length of antenna 1 peduncle article 1; lateral head lobe bluntly pointed, right angled to slightly acute; eyes large, inflated, occupying nearly entire lateral face of head. Antenna 1 with tiny accessory flagellum of single article with single simple seta apically; peduncle articles 1 and 2 with several robust setae distally; flagellum article 1 elongate, about as long as succeeding 3 articles combined. Antenna 2 peduncle articles 3–5 with several robust setae distally; flagellum proximal articles shorter than wide, gradually decreasing in width and increasing in length to approximately 4 times width. Labrum asymmetrical, with deep notch. Mandible lacinia mobilis present on both sides; molar low, rounded, non-triturative; accessory setal row reduced, with 3 short setae; palp article 3 with ventral row of plumose setae in distal third, 2 strong, serrate apical setae and 2 adjoining slender setae. Maxilliped palp article 3 apex rounded, without terminal dactylus.

Pereon. Pereonite 6 with small, flat dorsoposterior projection; pereonite 7 with dorsal carina and larger posterior projection. Coxae 1–4 each shorter than corresponding pereonite, gradually increasing in length from 1 to 4; coxa 4 with weakly serrate ventral margin. Gnathopod 1 slender, slightly larger than 2; propodus simple, 0.8 length of carpus; merus, carpus and propodus with long, finely dentate setae along posterior margin. Gnathopod 2 slender, similar to 1 in shape and setation, propodus simple. Pereopods 5–7 successively longer; basis posterodistally broadly rounded, posterior margin finely serrate.

Pleon. Pleonites 1 and 2 each with dorsal carina and dorsoposterior projection, strong lateral apodemic ridge with rounded posterior projection; epimeron 2 with acutely pointed posteroventral corner. Pleonite 3 with low dorsal carina, weak apodemic ridge, posterior margin of epimeron rounded, multiserrate. Uropod 1 outer ramus 0.6 x length of inner ramus. Uropod 2 outer ramus slightly more than 0.5 x length of inner ramus. Uropod 3 outer ramus approximately 0.7 x length of inner ramus. Telson entire, apex broadly rounded, ventrally thickened midlength but not distinctly keel-shaped, with 2 robust setae in midline.

Habitat. Among Halimeda opuntia algae, 10 m.

Remarks. Tepidopleustes acromatius sp. nov. is clearly distinguished from the only two Australian congeners, T. coffsiana and T. juliana , on account of its serrate third epimeron and its broadly rounded entire telson. Tepidopleustes acromatius differs from T. barnardi and T. honomu , the two species with serrate epimeron 3, by the enormous, bulbous eyes that cover almost the entire lateral surfaces of the head. The outer ramus of uropod 3 of T. acromatius is 2/3 the length of inner ramus, as in T. honomu , but 9/ 10 in T. barnardi . The lateral cephalic lobe in T. acromatius is acute, as in T. barnardi , but rounded quadrate in T. honomu . Tepidopleustes barnardi has the propodus of gnathopods 1 and 2 subchelate; in T. acromatius and the other three species the propodus is simple.

Distribution. Australia. Queensland: Yonge Reef, Great Barrier Reef.

Figures

FIGURE 1. Tepidopleustes acromatius sp. nov., holotype, male, 3.9 mm, AM P71533, Yonge Reef, Great Barrier Reef.

FIGURE 2. Tepidopleustes acromatius sp. nov., H, holotype, male, 3.9 mm, AM P71533, Yonge Reef, Great Barrier Reef. All other details, paratype, male, AM P77856.