Pleustidae * Author Just, Jean text Zootaxa 2009 2009-10-08 2260 1 836 840 https://www.biotaxa.org/Zootaxa/article/view/zootaxa.2260.1.46 journal article 10.11646/zootaxa.2260.1.46 1175-5326 5307959 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.