Atarbolana setosa Javed and Yasmeen, 1989

Khalaji-Pirbalouty, Valiallah & Raupah, Michael J., 2016, DNA barcoding and morphological studies confirm the occurrence of three Atarbolana (Crustacea: Isopoda: Cirolanidae) species along the coastal zone of the Persian Gulf and Gulf of Oman, Zootaxa 4200 (1), pp. 153-173 : 162-168

Atarbolana setosa Javed and Yasmeen, 1989

( Figs 7–11 )

Atarbolana setosa Javed and Yasmeen (1989): 79 , figs 1–2.

Type material. Holotype: ♂, ZMUKP-W. J–8; Paratypes: 2 ♂, ZMUKP. -W. J–9. Type locality. Manora Island, Karachi , 24°47'40"N 66°58'39"E.

Atarbolana dasycolus Yasmeen (2004): 21 , figs 1–3.

Type material. Holotype: ♂ (3.7 mm), Sandspit , Karachi ; Paratypes: 3 ♂ (3–5 mm), 4 ♀ (3–4 mm), Sandspit , Karachi ; 5 ♀ (4–4.3 mm), Bulleji , Karachi, Pakistan, ZMUKP .

Material examined. 3 ♂ (4.1, 4, 3.6 mm); 4 ♀ (5.1, 4.5, 4.2, 3.6 mm), Bahl village , Near Jask, Hormuzgan Province, Iran, Gulf of Oman, 25°40'48.95"N, 57°51'13.36"E, 28 June 2013, coll. V. Khalaji-Pirbalouty ( ZMSU 1014 ) . 3 ♂ (5.2, 4.6, 4.6 mm); 6 ♀ (5.5, 5.2, 4.5, 4.5, 4.2, 4.1 mm), Pasabandar , Sistan and Baluchestan Province, Iran, Gulf of Oman, 25° 4'15.93"N, 61°24'32.76"E, 20 May 2013, coll. V. Khalaji-Pirbalouty ( ZMSU 1015 ) . 2 ♂ (5.3, 5 mm), Djod village , Sistan and Baluchestan Province, Iran, Gulf of Oman, 25°26'56.40"N, 59°30'29.28"E, 0 9 October 2014, Ebrahimnezhad ( ZMSU 1016 ) .

Diagnosis. Body about 2 times as long as greatest width; pereonites 4–7, pleon and pleotelson bearing scattered small tubercles; flagellar articles in male bearing a tuft of long serrate and simple setae; pleotelson elongated, with narrowly rounded apex, posterior margin with 8–10 marginal RS; uropodal endopod not reaching to pleotelson apex, exopod nearly 1.7 times as long as endopod, extended well beyond pleotelsonic apex, peduncle ventromedial surface with a row of 7 RS; appendix masculina with a curve acute apex, arising above mid-point of endopod medial margin, extending much beyond endopod distal margin (by approximately 0.5 times of length).

Description of male (from Bahl village, Near Jask, Hormuzgan Province, Gulf of Oman, Iran) Body 2.2 times as long as greatest width, widest at pereonite 5 ( Fig. 7 A). Head with minute rostral process, with 2 posterior sutures. All pereonites posterior margins bearing long simple marginal setae; pereonites 4–7 bearing scattered small tubercles; pereonites 2–3 with sub-quadrate coxal plates; coxal plates 5–7 progressively more produced and acute posteriorly, all coxal plate ventral margin fringed with long simple setae ( Fig. 7 B).

Pleon ( Fig. 7 A) with pleonite 3 visible dorsally; pleonite 4 extended well over lateral margins of pleonite 5; pleonites 3–5 with scattered small tubercles.

Pleotelson ( Fig. 7 A, C) with 2 bimedian depressions, dorsal surface with 4 long simple setae and scattered small tubercles; posterior margin bearing 10 marginal RS set between long PMS ( Fig. 7 E, F).

Antennula ( Fig. 7 E) extending to posterior margin of pereonite 3, peduncle article 1 short, peduncle article 3 approximately 1.4 times as long as article 2; flagellum with 16 articles, articles 7–15 bearing 1 or 2 aesthetascs.

Antenna ( Fig. 7 F) peduncle articles 2–4 subequal in length, all articles each with a group of long simple setae on anterodistal corner, article 3 with 10 very long simple setae on ventral margin; flagellum with 16 articles, extending to middle of pereonite 1, articles 1–8 bearing a tuft of long setae (some serrated), articles 3–8 distoventral corner with a long simple seta.

Left mandible ( Fig. 8 A, B) molar process anterior margin with about 34 flat teeth; spine row composed of 11 spines; palp article 2 longest with 9 robust biserrate setae, 4 robust simple setae and 3 long submarginal RS; article 3 with 11 robust biserrate marginal setae.

Maxillula ( Fig. 8 C) lateral endite with 10 RS (weakly serrated); mesial endite with 3 large circumplumose RS and 2 short simple setae.

Maxilla ( Fig. 8 D) lateral and middle endites with 4 and 5 long finely plumose setae respectively; mesial endite with 6 long CRS and 3 simple RS.

Maxilliped palp ( Fig. 8 E) article 1 with 7 distally placed long setae, articles 2–5 lateral margins with 2, 9, 2 and 4 slender simple setae respectively; articles 3–5 with continuous fringe of finely biserrate setae on medial margin; endite ( Fig. 8 F) with 4 long CPS, and 3 coupling hooks.

Pereopod 1 ( Fig. 9 A) basis 3.1 times as long as wide, superior margin with 4 long simple and 2 SPS, posterodistal corner with 4–5 long finely plumose setae; ischium inferior margin with 2 long simple setae, mediodistal margin with 4 long simple setae; merus inferior margin with 3 RS and 4 long simple setae, mediodistal margin with 2 long simple setae, superior margin with 3 long simple setae; carpus inferior margin with 3 RS and 3 long simple setae; propodus inferior margin with 8 RS and 2 sets of sub-marginal slender simple seta, superior margin with 2 simple setae, superodistal corner with 2 simple and 1 plumose setae; dactylus with minute secondary unguis.

Pereopod 2 ( Fig. 9 B) basis 2.6 times as long as wide, superior margin with 6 long simple and 2 SPS, posterodistal corner with 5 long finely plumose or simple setae; ischium inferior margin with 3 long simple setae, mediodistal margin with 4 long simple setae, superiodistal corner with 3 long simple setae and 1 long RS; merus inferior margin with 5 RS and 2 long simple setae, superodistal corner with 3 long simple setae and 1 RS, mediodistal margin with 3 long simple setae; carpus inferior margin with 2 RS and 3 long simple setae; propodus inferior margin with 5 RS, superodistal corner with a SPS and 4 simple setae; dactylus with minute secondary unguis.

Pereopod 3 ( Fig. 9 C) similar to pereopod 2.

Pereopod 4 ( Fig. 9 D) basis 2.5 times as long as wide, with 3 long simple marginal and 2 SPS, posterodistal corner with 3 long simple setae and 1 long finely biserrate setae; ischium inferomedial surface with 4 long simple setae and 2 RS, inferodistal corner with 3 long RS, superodistal corner with 3 RS, mediodistal margin with 7 long simple setae; merus inferomedial surface with 3 RS, inferodistal corner with 4 long simple RS and 1 serrate RS, superodistal corner with 4 RS; carpus inferodistal corner with 4 simple RS and 2 serrated RS, superior distal corner with 3 RS; propodus inferodistal margin with 2 RS; dactylus with minute secondary unguis.

Pereopod 5 ( Fig. 10 A) and Pereopod 6 ( Fig. 10 B) are similar to pereopod 4 as illustrated.

Pereopod 7 ( Fig. 10 C) basis 2.7 times as long as wide, posterodistal corner with 3 simple, 2 finely biserrate RS and 5 long simple setae; ischium inferior margin with 2 sets of long simple setae and 2 RS, inferodistal corner with 1 simple and 5 biserrated RS, superodistal corner with 4 simple and 1 biserrated RS; merus and carpus superior and inferior margins fringed with numerous long plumose setae; propodus inferior margin with 2 RS, superodistal corner with 1 RS, 1 simple and 1 SPS; dactylus with minute secondary unguis.

Pleopod 1 ( Fig. 11 A) exopod and endopod with ~46 and 20 PMS, endopod longer and narrower than exopod; sympod mesial margin with 4 coupling hooks and 1 plumose seta, lateral margin with a single RS.

Pleopod 2 ( Fig. 11 B) exopod and endopod with ~51 and 17 PMS respectively; appendix masculina arising above 0.5 of endopod medial margin, extending much beyond endopod distal margin (by approximately 0.5 times of length), tapering to a curve acute apex; sympod mesial margin with 3 coupling hooks and 2 plumose setae, lateral margin with a single sub-marginal RS.

Pleopod 3 ( Fig. 11 C) and Pleopod 4 ( Fig. 11 D) essentially similar, exopod with ~70 and ~59 PMS, and an entire transverse suture; sympod medial margin with 3 and 4 coupling hooks and 2 plumose setae, lateral margin with single sub-marginal RS.

Pleopod 5 ( Fig. 11 E) exopod with 60 PMS, and entire transverse suture; sympod without coupling hook, lateral margin with single sub-marginal RS.

Penes ( Fig. 11 F) short, separate but adjacent, 2.8 times as long as basal width.

Uropod ( Fig. 10 D); endopod not reaching to pleotelsonic apex, with 21 marginal RS; exopod ( Fig. 10 E) elongate, slender, nearly 1.7 times as long as endopod, extended well beyond pleotelsonic apex, dorsolateral margin with 2 RS, ventromedial margin with 6 RS, distal margin with a tuft of long simple setae, 1 prominent RS and 1 small RS; peduncle ventromedial surface with a row of 7 RS.

Female. Apart from sexual characters differs from male by having an antenna without tuft of long setae on flagellum articles; uropod rami smaller than in male and extending just beyond the pleotelsonic apex, endopod with 18 marginal RS, exopod dorsolateral margin with 2 RS, ventro-medial margin with 4 RS; pleotelson with 8 marginal RS, elongation less than in male.

Variations. Pleotelson marginal RS (n = 17 [8 ♂ and 9 ♀]) males with 8 –10 RS (100%); in females with 8–10 RS, with 8 RS (44%), 10 RS 44%), and (11%) occurring only once; Uropod endopod in males with 11–21 RS, with 18 RS (62%) most frequent, and 19, 20 and 21 occurring only once; in females with 17–18 RS, with 17 RS (55%) most frequent, and 18 RS (44%).

Remarks. The species Atarbolana setosa was originally briefly described by Javed & Yasmeen (1989) from Karachi, Pakistan. In the original brief description several important characters including pereopods 3–7, mouth parts, variations of the pleotelson marginal robust setae and number of the uropodal endopod marginal robust setae were not mentioned or figured. Nevertheless, this species can be recognized by a) the elongate appendix masculina which extends much beyond the apex of the endopod of the pleopod 2, b) the antennal flagellum with tufts of long and dense setae and antennal peduncle article 3 with ~10 very long simple setae on ventral margin, and c) the ventral surface of the uropod peduncle with a row of 7 robust setae. Nevertheless, Atarbolana setosa is similar to A. makranensis in having an antennal flagellum with tufts of long and dense setae. However, this species can be clearly distinguished from A. makranensis by having an elongated appendix masculina, which extends well beyond the apex of the endopod of the pleopod 2. Furthermore, the pleotelson of A. setosa extends just to the endopod apex, whereas in A. makranensis the pleotelson extends well beyond the uropodal endopod.

Atarbolana dasycolus recorded from the Karachi coast ( Pakistan) matches key characters of A. setosa including an elongated appendix masculinum and antennal flagellum with tufts of long and dense setae. The main nominal difference between them is the number of pleotelson and also uropodal endopod marginal robust setae. Atarbolana dasycolus is described as having a pleotelson with 8 (rather than 10) marginal robust setae and uropodal endopod with 11 marginal robust setae (rather than 16). However, all examined material from three species of the genus Atarbolana show variation in the number of pleotelson and also uropodal rami robust setae and Yasmeen (2004) did not outline other differences. Based on description and illustration given by Yasmeen, 2004, and the size (3.7 mm) of the holotype specimen, we conclude A. dasycolus is based on no more than small male of A. setosa and therefore is a junior synonym of A. setosa .

Distribution. Karachi, Pakistan (Manora Island, Sandspit, Bulleji); Gulf of Oman, Iran (Bahl village, Djod village, Pasabandar).

Figures

FIGURE 7. Atarbolana setosa, male, (ZMSU 1014); A, dorsal view; B, lateral view; C, pleotelson apex; D, female pleotelson; E, antennula; F, antenna.

FIGURE 8. Atarbolana setosa, male, (ZMSU 1014); A, left mandible; B, maxillula; C, maxilla; D, maxilliped; E, maxilliped endite.

FIGURE 9. Atarbolana setosa, male, (ZMSU 1014); A – D, pereopods 1 – 4 respectively.

FIGURE 10. Atarbolana setosa, male, (ZMSU 1014); A – C, pereopods 5 – 7 respectively; D, uropod dorsal view; E, uropod ventral view.

FIGURE 11. Atarbolana setosa, male, (ZMSU 1014); A – E, pleopods 1 – 5; F, penes.