Heterodina qeshmensis Khalaji-Pirbalouty & Bruce, 2014, sp. nov.

Heterodina qeshmensis sp. nov.

(Figs 1–3)

Material examined. Holotype. ♂ (1.6 mm); Kovei, Qeshm Island, north-eastern coast, Persian Gulf, 3 m depth, from coral reefs, 26°57’279”N, 55°59’340”E, 13 November 2009, coll. M. S. Ranjbar (ZMH –K–42602). Paratypes: 1 ♂ (1.5 mm), 3 ♀♀ (ovig. 1.6, 1.9, 2.0 mm), same data as holotype (ZUTC Iso. 1107). Also examined: Paratypes of Heterodina mccaini Schotte & Kensley, 2005, Manifa, Ras Tanajib, Saudi Arabia, Persian Gulf, 12 November 1981 (USNM 280351).

Description of male. Body oval, smooth, moderately convex, about twice (1.9) as long as greatest width, widest at pereonite 5 (Fig. 1 A). Head with weak rostral point, disto-lateral part not embraced by pereonite 1. Eyes round laterally embraced by extension of pereonite 1. Pereonites unornamented; pereonites 2–7 with coxal plate sutures clearly visible on dorsal sides; coxal plates fringed with fine marginal setae; pereonites 2 and 3 equal, shortest; pereonites 5 and 6 sub-equal longest.

Pleon sub-equal in length to pereopod 7, posterior margin bearing a single short suture line on either side.

Pleotelson 0.6 times as long as anterior width, with narrowly rounded apex, posterior margin fringed with fine setae (Fig. 1 A)

Antennula (Fig. 1 B) extending to posterior margin of pereonite 1; peduncle articles 1 stout, peduncle articles 2 and 3 sub-equal in length; flagellum with 6 articles, articles 3 and 4 each bearing an aesthetasc.

Antenna (Fig. 1 C) extending just beyond to posterior of pereonite 1, peduncle article 5 longest; flagellum with 7 articles.

Epistome (Fig. 1 D) visible dorsally between antennal bases, with slightly concave posterior margin, bearing some marginal setae, lateral margins concave; labrum laterally enclosed by epistome posterior extensions.

Left mandible (Fig. 1 E, F) incisor with 4 cusps, spine row of 2–3 curved, serrate spines; molar process round; palp articles 2 and 3 with 3 and 6 biserrate setae respectively.

Maxillula (Fig. 1 G) lateral endite with 4 simple RS and 2 serrate RS on apical margin, mesial endite with 4 long comb setae and 1 small simple seta.

Pereopod 1 (Fig. 1 I) basis about 2.4 times as long as greatest width; ischium superior margin with 2 simple RS; inferior margin fringed with 6 small setae; merus infero-distal corner with 1 long RS, supero-distal corner with 1 long biserrate RS; carpus triangular, with 1 biserrate RS on infero-distal corner; propodus inferodistal corner with 1 biserrate seta, 1 serrate RS and 1 simple seta, supero-distal corner with 1 palmate sensory seta; dactylus with a small secondary unguis.

Pereopod 2 (Fig. 1 J) similar to pereopod 3 (Fig. 2 A) merus and carpus sub-equal in length, merus supero-distal corner with 1–2 biserrate setae, carpus supero-distal corner with a single palmate sensory seta.

Pereopods 4 and 5 (Fig. 2 B, C) are shorter than pereopods 2–3, merus supero-distal corner with 2 long biserrate RS.

Pereopods 6 and 7 (Fig. 2 D, E) are similar except in some details such as the number of serrate RS on distal margin of carpus.

Pleopod 1 (Fig. 3 A) exopod and endopod with 8 and 2 PMS; exopod 1.7 times longer than narrower endopod, medial margin with a single long simple seta; sympod mesial margin with 2 coupling hooks, lateral margin with single long simple seta.

Pleopod 2 (Fig. 3 B) exopod and endopod equal in length, with 12 and 7 PMS respectively; appendix masculina arising sub-basally bearing tiny short setae on lateral margin distally, single plumose seta on rounded apex; sympod mesial margin with 2 coupling hooks, disto-lateral corner with a single simple seta.

Pleopod 3 (Fig. 3 C) exopod and endopod with 14 and 8 PMS, exopod narrower than endopod, lacking transverse suture; sympod with 3 coupling hooks, lateral margin with single long simple seta.

Pleopod 4 (Fig. 3 D) both rami subequal in length, with very weak transverse folds, exopod lateral margin with 2 fine simple setae.

Pleopod 5 (Fig. 3 E) exopod with 2 scale patches, mesial margin with 3 fine simple setae.

Penial process (Fig. 3 F) basally fused, elongated, tapering steadily to rounded apices, about 4.4 times as long as basal width.

Uropod (Fig. 1 H) extending to distal margin of pleotelson; endopod much longer than exopod, about 4.4 length of exopod; distally rounded, exopod and endopod lateral margins fringed with long slender setae interspersed among smaller fine setae.

Female: Similar to male with the exception of the sexual characters.

Remarks. Heterodina qeshmensis sp. nov., can be identified by the unornamented dorsal surfaces, wide and anteriorly concave epistome, and the appendix masculina with sub-parallel margins and not extending beyond the distal margin of the endopod.

The new species is most similar to Heterodina mccaini Schotte & Kensley, 2005 from the southern coast of the Persian Gulf. Based on the examination of type material (USNM 280351), the new species differs from H. mccaini, in having the penial processes fused along two-fifths of their length, with rami diverging abruptly before tapering to the rounded apices. The correct shape of the penial processes was not clearly shown in the original illustration and is figured here (Fig. 3 G, USNM 280351). Penial processes with diverging rami and small acute scales on the distal surface were found in adult male, as well as sub-adult specimens of H. mccaini. Moreover, H. mccaini differs by having a pleopod 2 with basally swollen appendix masculina, which extends well beyond the apex of the endopod. Furthermore, merus, carpus and propodus of pereopods are more setose in H. mccaini.

Etymology. The epithet of the new species refers to its type locality, Qeshm Island (the largest island in the Persian Gulf).