Sphaeromopsis sarii, Khalaji-Pirbalouty, Valiallah & Wägele, Johann-Wolfgang, 2009

Khalaji-Pirbalouty, Valiallah & Wägele, Johann-Wolfgang, 2009, Two new species of Sphaeromopsis (Crustacea: Isopoda: Sphaeromatidae) from the Persian Gulf, Zootaxa 2305, pp. 33-50 : 34-42

Sphaeromopsis sarii sp. nov.

( Figs 1–5 )

Material examined. All material from the Iranian shores of the Persian Gulf.

Holotype: male (2.6 mm), Kish Island, Kish Hospital, sandy beaches, 24 June 2006, 26°30’109” N, 53°57’386” E, coll. V. Khalaji (ZMH-42315).

Paratypes: 1 male (2.5 mm); 3 subadult males (up to 2.3 mm); 3 juveniles (up to 2.1mm); 1 ovigerous female (2.8 mm); 2 non-ovigerous females (up to 2.4 mm), same data as holotype (ZMH-42316); Kish Gas, 10 December 2008, 26°29’416” N, 53°59’494”E, sandy beaches; 2 male (up to 2.5 mm); 6 subadult males (up to 2.4 mm); 2 juveniles (up to 2.2 mm); 11 non-ovigerous females (up to 2.4 mm), coll. Lotfallah & Ismaeil Khalaji (ZMH-42317); Harrireh, in clumps of algae, 26 Jun 2009, 26°34’203” N, 53°57’444” E, 10 adult male (up to 2,9 mm); 6 non-ovigerous female (up to 2.4 mm), coll. Reza & Valiallah Khalaji (ZMH-42318); Qeshm Island, Sea Cinema, 0 8 December 2007, 26°56’136” N, 56°58’296” E, in the tide pools; 1 adult male; 3 subadult males; 3 juveniles; 5 non-ovigerous females, coll. V. Khalaji & A. Bahpouri (ZMH-42319).

Diagnosis. Body 2.2 times as long as wide; head with trapeziform rostrum; eyes large, postero-laterally located; pereonite 2–7 with coxal plate sutures clearly visible on lateral sides; pleon with posterior margin bearing 2 short, separate sutures at either side; pleotelson with faint medial furrow in dorsal view, posterior margin produced to broadly rounded apex; pereopods 1–3 with setulose fringe on inferior margins of ischium, merus, carpus and propodus; uropod exopod lateral margin and endopod distolateral margin serrate.

Description of male. Body 2.2 times as long as greatest width; head smooth, with 2 clear and some faint tubercles in dorsal view, moderately convex with trapeziform rostrum barely visible in dorsal view. Pereonites 1–7 smooth, or with some very faint tubercles; pereonite 1 with convex depression on each dorsal side anteriorly into which the posterior eye borders fit; pereonites 2–7 with coxal plate sutures clearly visible on lateral sides; coxae 2–7 subequal, ventral margin with short setae, coxae 2–3 subtruncate and lateral margin narrower than others, more rounded laterally in pereonites 4–6. Pleon posterior margin bearing two separate sutures on either side. Pleotelson wider than long, forming a dorsal arch in posterior view and with faint tubercles over surface, bearing in anterior half a faint dorsomedial furrow; posterior margin produced to broadly rounded apex, lateral margins folded ventrally.

Antennule basal article about 2 times as long as article 2, article 3 about 1.4 as long as article 2; flagellum 8–articled, extending to posterior margin of pereonite 1, articles 2–5 each bearing aesthetascs. Antenna peduncle article 5 about 1.2 times as long as article 4; flagellum extending to level of pereonite 2, with 11 articles.

Epistome ( Fig. 6A ) with narrowly rounded sub-triangular apex, lateral margins concave, posterolateral lobes extending to mid-length of labrum.

Maxillule lateral lobe mesial margin with some simple setae, apical margin with 8 robust setae, some inferiorly serrate, mesial lobe with 4 comb and 2 simple setae. Maxilla lateral and middle lobes with 4 curved nodular serrate robust setae; mesial lobe with 2 serrate robust and 4 stout simple setae, mesial margin with many short simple setae. Right mandible incisor with 4 cusps, lacinia mobilis with 3 cusps; spine row of 4 curved, serrate spines; molar process round, crushing surface ridged; palp article 2 longer than 1, article 2 distolateral margin with 5 biserrate setae becoming progressively longer distally; article 3 with 7 biserrate setae, terminal seta being longest. Maxilliped endite lateral margin weakly sinuate, distal margin with 3 blunt robust setae, set in amongst 5 distal and 1 sub-distal circumplumose robust setae; mesial margin with 1 coupling hook and 2 simple setae; palp articles 1–5 with about 1, 7, 8, 3 and 6 setae respectively.

Pereopod 1 robust, basis about 2.4 times as long as greatest width, distal superior margin fringed with short scale-setae and 2 small sensory palmate seta, inferodistal angle with single long simple setae; on ischium, merus, carpus and propodus inferior margin fringed with short setae; ischium about 2 times as long as greatest width, superior margin with 4 long distally biserrate setae; merus 0.5 times as long as ischium, superodistal angle with single long distally biserrate and single biserrate robust setae, carpus approximately as long as wide, subtriangular, inferodistal angle with single biserrate robust seta; propodus 2.9 times as long as wide, 2 biserrate robust setae, superodistal corner with single sensory palmate seta; dactylus inferior margin with cuticular scales, secondary unguis curved, with 3 simple setae at base, superior margin with single seta, distal margin with 2 simple sub-marginal setae.

Pereopod 2 basis about 4 times as long as wide, superior margin fringed with short scale-setae and single small sensory palmate seta; on ischium to propodus inferior margin fringed with short setae; ischium about 3.3 times as long as greatest width, superior margin with 4 long distally biserrate setae and single proximal simple seta; merus 0.5 times as long as ischium, superodistal angle with 4 long distally biserrate setae; carpus superodistal angle with single simple seta; propodus 0.7 times as long as ischium, superodistal corner with 2 palmate setae(1 long sensory, 1 short); dactylus inferior margin with cuticular scales, secondary unguis curved, with 3 simple setae at base, superior margin with single scale seta, distal margin with 2 simple submarginal setae. Pereopod 3 similar to pereopod 2 as illustrated. Pereopod 4 ischium without short setae fringe on inferior margin; carpus with 2 palmate setae (1 long sensory, 1 short). Pereopod 5 similar to pereopod 4 as illustrated.

Pereopod 6 basis about 3.6 times as long as greatest width; ischium about 2.6 times as long as greatest width, superior margin with 4 long distally biserrate setae; on merus, carpus and propodus inferior margin fringed with short setae; merus 0.5 times as long as ischium, superodistal angle with 6 long distally biserrate setae; carpus subequal in length to merus, inferodistal angle with single biserrate robust seta, superodistal angle with 1 biserrate robust and 1 sensory palmate seta; propodus superodistal corner with 3 palmate setae (1 long sensory, 2 short); dactylus inferior margin with cuticular scales, secondary unguis curved.

Pereopod 7 basis about 3.8 times as long as greatest width, inferodistal angle with 1 simple setae, superior margin with short fringe scale setae, with 2 small sensory palmate seta, dorsal surface with 6 widely spaced small sensory palmate seta; ischium 0.7 times as long as basis, 3 times as long as greatest width, superior margin with 4 long distally biserrate setae; on merus to propodus inferior margin fringed with short setae; merus 0.5 times as long as ischium, superior distal margin with 3 long distally biserrate setae; carpus subequal in length to merus, inferodistal angle with 2 biserrate robust seta, superodistal angle with 2 biserrate robust setae; propodus superodistal corner with 3 palmate setae (1 long sensory, 2 short); dactylus inferior margin with cuticular scales, secondary unguis curved, with 3 simple setae at base, superior margin with single scale seta, distal margin with 2 simple sub-marginal setae.

Penes 5.3 as long as basal width, fused along basal 0.37 of length, widening slightly, reaching maximum width at two-fifth length and then tapering to acute and curved apices.

Pleopod 1 exopod and endopod with 20 and 14 plumose marginal setae respectively; endopod lateral margin proximally truncate and rest of margin concave, mesial margin with short fringe setae; exopod lateral margin proximally with single long, distally biserrate seta, distal margin subtruncate; sympodite mesial margin extended, with 3 coupling hooks and some toothed scales. Pleopod 2 exopod and endopod equal in length, margin with 21 and 13 plumose setae respectively; appendix masculina bearing tiny short setae on proximal medial margin, arising sub-basally, single plumose seta on narrowly rounded apex; sympodite with 3 distomesial coupling hooks. Pleopod 3 exopod and endopod with 22 and 12 plumose marginal setae respectively; sympodite with 3 distomesial coupling hooks, lateral margin with fringe of thin setae and single long simple seta on distolateral corner; endopod mesial margin straight with fringe of thin setae. Pleopod 4 both rami subequal in length, mesial margins with some fine simple setae. Pleopod 5 exopod with 3 scale patches (2 distally of and 1 under transverse suture), mesial margin with some fine simple setae.

Uropod extending to distal margin of pleotelson; endopod longer than exopod, lateral and medial margins with fringe of fine short setae and some long simple seta on apical margin, distolateral margin serrate; exopod lateral margin serrate bearing some simple or palmate setae (single seta on each notch), medial margin with fringe of fine short setae.

Etymology. This species is named for Dr. Alireza Sari, to acknowledge many years of contributions to the zoology of Iran, especially his work on crustaceans.

Remarks. This species can be easily recognized by the dorsomedial furrow on the pleotelson. Among all known Sphaeromopsis species, only S. sulcifera Schotte & Kensley, 2005 has a faint longitudinal, dorsomedial furrow on the pleotelson. Sphaeromopsis sarii sp. nov., is the second species exhibiting this feature, but is readily distinguished from S. sulcifera by its long, slender penes that are fused basally, tapering to rounded apices with patches of tiny setules around the margins of their anterior half. Both species differ also in the shape and setation of pleopods 2, 4 and 5.

Sphaeromopsis sarii sp. nov. is closely related to S. amathitis Holdich & Jones, 1973 . Based on the description of S. amathitis given by Holdich and Harrison (1981) and on examination of topotypic material (MTQ W14091, Museum of Tropical Queensland), the new species differs from S. amathitis , which has a broadly truncate pleotelson, an epistome with a trapezoid apex and more foraminate tubular setae, as well as differently shaped penes. Sphaeromopsis sarii differs from S. minutus Javed & Yousuf, 1995 (from Pakistan), which has a broadly rounded pleotelson with setules on the apex, an epistome with a subacute apex, and penes with curved rami, that taper inwards in their proximal part and form narrow and outwardly directed apices.

Figures

FIGURE 1. Sphaeromopsis sarii sp. nov., holotype (male). A, dorsal view; B, lateral view; C, antenna; D, antennule; E, ventral view of pleotelson.

FIGURE 2. Sphaeromopsis sarii sp. nov., holotype (male). A, maxillule; B, right mandible; C, maxilla; D, maxilliped.

FIGURE 3. Sphaeromopsis sarii sp. nov., holotype (male). A – D, pereopods 1 – 4, respectively.

FIGURE 4. Sphaeromopsis sarii sp. nov., holotype (male). A – C, pereopods 5 – 7, respectively.

FIGURE 5. Sphaeromopsis sarii sp. nov., holotype (male). A – E, pleopods 1 – 5, respectively; F, uropod; G, penes.

FIGURE 6. A – B, Sphaeromopsis sarii sp. nov. (paratype); A, frons and anterior of head in ventral view; B, dorsal view of pleotelson. C – F, Sphaeromopsis persikolpos sp. nov. (paratype); C, frons and anterior of head in ventral view; D, dorsal view of pleotelson; E, a foraminate tubular seta on pleotelson; F, hand-like scales on distal third of penes rami.