Cirolana bitari, Castelló, 2017

Castelló, José, 2017, New and little-known species of isopods (Crustacea, Isopoda) from the eastern Mediterranean, Zootaxa 4311 (2), pp. 151-182 : 163-169

Cirolana bitari sp. nov.

( Figs 9–11 )

Material examined. Holotype: adult male, 7.7 mm, sample 5M37, station 7, Beirut Harbor, Lebanon, 33°54'26”N, 35°31'16”E., 14 m, inner side of the breakwater, no ecological data, G. Bitar & H. Zibrowius coll., 9 July 2003 ( MZB2016-3482 : 19 slides).

Paratypes: female, 7.3 mm, sample 5M37, same locality as holotype ( MZB2016-3483 ) ; juvenile, 2.8 mm (dissected, 19 slides), sample 5M8, stn. 10: Beirut Harbor outer side of breakwater ( MZB2016-3571 ) ; female, 4.8 mm, sample 5M9, stn. 10: Beirut Harbor outer side of breakwater ( MZB2016-3572 ) ; female, 4.2 mm, sample 5M19, stn. 3: Tripoli inside harbor ( MZB2016-3573 ) ; female, 4.7 mm, sample 5M19, stn. 3: Tripoli inside harbor ( MZB2016-3574 ) ; male, 5.0 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3575 ) ; male, 6.2 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3576 ) ; female, 4.3 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3577 ) ; female, 5.2 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3578 ) ; female, 6.4 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3579 ) ; juvenile, 3.9 mm, sample 5M23, stn. 12: Beirut Airport pier ( MZB2016-3580 ). Depth: between 2 and 15 m. G. Bitar & H. Zibrowius coll., between 16 Sept. 2002 and 9 July 2003.

Diagnosis. Body flat, depressed, about 3.0 times as long as wide. Dorsal surface of body without tubercles. Posterior margin of pereonites and pleonites without denticles or nodules. Pleonite 4 notched. Stiff setae on pleonite 5 and pleotelson. Frontal lamina pentagonal. Antenna 2 reaching beginning of pereonite 3. Articles of antennal flagellum with tuft of simple setae on anterodistal angle. Penes flat, well developed.

Description of holotype [MZB2016-3482]. Body about 3.0 times as long as width, depressed, widest on pereonite 5. Cephalon without dorsal furrows and with anterior margin rounded, not produced. Frontal lamina pentagonal not visible in dorsal view, separating antennular bases. Eyes lateral, rounded, with about 60 ommatidia; slightly covered by pereonite 1. Pereonite 1 longest, with lateral furrow on each side. Pereonite 2 also with lateral furrow. Pereonites 2–7 subequal in length. Posterior margin of pereonites without denticles or nodules. Coxae 4–7 with oblique carina; coxae 2–3 with posterior margin almost straight; coxae 4–7 with posterior margin oblique. Pleonite 1 largely concealed by pereonite 7. Pleonites 2–4 subequal in length, with concave posterior margin, especially last one. Pleonite 5 longest. Posterior margin of pleonites without denticles or nodules. Pleotelson triangular with slightly rounded margins; apex acute with 8 robust setae interspersed with plumose setae (also in paratype female 7.3 mm (sample 5M37) [MZB2016-3483]); dorsal surface without nodules, almost entirely covered by stiff setae, also present on pereonite 5.

Antenna 1 with peduncle of 4 articles; article 2 slightly longer than article 1; article 3 longest; article 4 minute; flagellum of 16 articles; aesthetascs from article 2 forwards; 3 simple setae and sensory seta at the apex. Antenna 1 almost reaches posterior margin of pereonite 1. Antenna 2 progressively increase in length; tuft of setae on anterodistal angle of articles, and some setae on anterior margin; sensory seta on posterodistal angle of article 5; flagellum of 19 articles (right antenna 2 broken off at the apex, losing two last articles); tuft of setae on anterodistal angle of articles. Antenna 2 reaching pereonite 3.

Mandible with incisor with 3 cusps, external one longest; molar process well produced with a continuous row of 21 teeth (right mandible), not placed on margin but on one side; on the opposite side there is a ridge of setae, 3 of them longest, almost reaching apex; spine row with 5 robust setae (right mandible); palp with 3 articles; articles 2– 3 setose; apical article with about 15 pectinated setae. Maxilla 1 exopod with 8 stout setae and 2 short setae; endopod lost during dissection. Maxilla 2 inner lobe with 10 plumose setae and 3 simple setae; medial lobe with 11 simple setae; outer lobe with 4 simple setae. Maxilliped with endite extending to mid-point of palp article 2, distally with coupling hook and 4 plumose setae; palp article one with mediodistal seta; article 2 with seta on externodistal angle, and 6 setae on internodistal angle; article 3 with 3 setae on external margin, and 10 setae on internodistal angle; article 4 with 2 setae on external margin, and 12 setae on internodistal angle, 3 of them pectinated; article 5 with 3 setae on external margin, and 10 setae at apex, 4 of them pectinated.

Pereopod 1 basis stout with 3 setae on posterodistal angle; ischium with 2 setae on anterodistal angle, tubercular blunt seta near posterodistal angle; merus with 3 setae on anterodistal angle, posterior margin with 6 tubercular blunt stout setae and robust pectinated seta between the fourth and fifth, medial side without setae; carpus triangular laterally, posterior margin with 2 setae on distal angle, and 2 other setae more centered; propodus with 2 setae on anterodistal section, posterior margin toothed with 2 robust setae, last of them stoutest and placed on posterodistal angle; 3 simple setae in same position on medial side. Pereopod 2 similar but less robust than pereopod 1; the main differences are: ischium with 2 tubercular blunt stout setae near posterodistal angle, merus with 9 tubercular blunt stout setae on posterior margin, some of them pectinated, carpus with 2 robust setae on anterodistal angle, and propodus with posterior margin only sinuate, not toothed, and with 3 robust setae. Pereopod 3 similar to pereopod 2 but less robust; the main differences are: ischium with 3 setae on anterodistal angle, merus with 12 tubercular blunt stout setae on posterior margin, some of them pectinated, carpus with 3 robust pectinated setae on posterodistal angle, and one other seta more centered, and propodus with posterior margin smooth. Pereopods 4–7 similar but becoming longer posteriorly; basis with short simple setae on anterior margin (pereopods 4–7), a group of 5 (pereopods 4–6) or 4 (pereopod 7) setae on posterodistal angle, ischium with 5 (pereopod 4), 8 (pereopods 5-6) or 9 (pereopod 7) setae (bifurcated or pectinated) on anterodistal angle, posterior margin with four groups of 5, 2, 3 and 5 (pereopod 4), 5, 2, 3 and 4 (pereopod 5), 5, 2, 2 and 3 (pereopod 6), and 4, 2, 3 and 3 (pereopod 7) bifurcated setae, merus with 5 (pereopod 4), 6 (pereopod 5), 11–12 (pereopod 6), and 8 (pereopod 7) bifurcated setae (2–3 of them serrated in pereopod 6) on anterodistal angle, posterior margin with two groups of 9 and 12 (pereopod 4), 8 and 9 (pereopod 5), 4 and 8 (pereopod 6), and 4 and 11 (pereopod 7) bifurcated setae, carpus with one (pereopods 4–5), 8 (pereopod 6), and 4 (pereopod 7) bifurcated setae (3–4 of them serrated in pereopod 6), posterior margin with three groups of 3, 5 and 7 (pereopod 4), 3, 4 and 6 (pereopod 5), 2, 4 and 7 (pereopod 6) or four groups of one, 3, 4 and 10 (pereopod 7) bifurcated setae, propodus with 2 bifurcated setae on anterodistal angle (pereopods 4–7), posterior margin with four groups of one, 2, 2 and 2 (pereopods 4–5), 2, 2, 3 and 2 (pereopod 6), and 2, 2, 2 and 2 (pereopod 7) bifurcated setae.

Penes present, flat, well developed.

Pleopod 1 rami subequal in length; medial margin of peduncle with 4 coupling-hooks, and 3 plumose setae on a triangular boss; external margin with stout seta; endopod and exopod with 14 and 40 plumose setae respectively; exopod with stout seta near the peduncle. Pleopod 2 rami subequal in length; medial margin of peduncle with 3 coupling-hooks, 3 plumose setae on a triangular boss, and 3 plumose setae on margin; external margin with stout seta; endopod and exopod with 21 and 40 plumose setae respectively. Appendix masculina robust, curved, surpassing length of endopod and reaching beyond half of length of setae; proximal section of appendix masculina with short setae and distal section with scales of short setae; thin and winding apex. Pleopods 3–5 exopod slightly longer than endopod; exopod with incomplete suture. Sympod of pleopods 3–4 with 3 coupling-hooks; sympod of pleopod 3 with 2 plumose setae on triangular boss, and 4 plumose setae on inner margin; sympod of pleopod 4 with plumose seta on triangular boss and 4 plumose setae on inner margin. Pleopod 3 with robust seta on outer margin of sympod, and 16 and 45 plumose setae on endopod and exopod respectively. Pleopod 4 sympod with stout seta on outer margin, and 13 and 46 plumose setae on endopod and exopod respectively. Pleopod 5 with stout seta on external margin of sympod; endopod without setae and 48 plumose setae on exopod.

Uropods clearly surpassing apex of pleotelson; endopod longer than exopod. Peduncle ventrolateral angle with 5 robust setae. Endopod length:width ratio 2.3; both margins serrated; outer margin with 9 stout robust setae interspersed with plumose setae, both absent in proximal third; apex bifid with tuft of plumose setae same as those of margin, and long simple setae; inner margin with 8 stout bifid setae interspersed with plumose setae, both absent in proximal third. Exopod length:width ratio 2.8; lateral margin convex and slightly serrated, with 7 short robust setae and plumose setae along entire margin; apex bifid with tuft of simple setae; internal margin serrated with 3 stout setae and plumose setae along margin, except on proximal fifth.

Color in alcohol yellowish brown, without cromatophores.

Variation. Pleonite 1 totally concealed by the pereonite 7 in the juvenile 3.9 mm, the females 4.3–4.8 mm, and the female paratype 7.3 mm.

Pleotelson with only a few dorsal setae in the juvenile 2.8 mm; pleotelson without dorsal setae in the juvenile 3.9 mm, the females 4.2–6.4 mm, and the male 5.0 mm. Pleotelson with apex more rounded in the male 5.0 mm.

Antenna 2 with 16 articles in the female paratype 7.3 mm.

Etymology. The species is named after Dr. Ghazi Bitar, Lebanese University, Hadath, Lebanon, in recognition of his organization of the sampling campaigns that allowed the collection of specimens studied.

Remarks. Bruce (1986) established several groups for the Australian species of Cirolana on the basis of the presence or absence of nodular dorsal sculpture, and lateral margin of uropodal exopod with or without continuous marginal setae. These criteria, applied to the two new species described in this study, place C. bitari sp. nov. in the “ Cirolana parva group”, with unornamented pereon, and pleon and pleotelson with reduced or absent ornamentation, and also external margin of uropodal exopod with 6–10 stout setae. To this same group belong C. cranchi Leach, 1818 and C. ferruginosa Risso, 1826 , the only species mentioned in the Mediterranean (WoRMS database, accessed 2 May 2017), the former also found in the collection of this study together with C. manorae Bruce & Javed, 1987 . C. manorae belongs to the “tuberculate group” and is related to C. zibrowiusi sp. nov. Since Bruce & Javed (1987) compare C. manorae and C. bovina Barnard, 1940 , in the present study the two new species are also compared with this latter species.

Cirolana bitari sp. nov. is easily distinguished from C. cranchi and C. manorae because the male has flat welldeveloped penes (absent in C. cranchi and C. manorae ). Furthermore, C. manorae has two nodules on pleonite 5 and four nodules on pleotelson, located at the level of initiation of the uropodal protopod, unlike C. bitari sp. nov., which has no nodules. The dorsal surface of the pleotelson is covered with stiff setae, absent in C. manorae .

The absence of nodules and granules on pleonite 5 and the pleotelson of C. bitari sp. nov. is a clear difference with respect to C. bovina . Bruce & Javed (1987) include a table comparing C. bovina and C. manorae ; an additional character that is not mentioned but is apparent is the length of antenna 2, which in C. bovina reaches the end of pereonite 4, while in C. manorae it only reaches pereonite 2. In C. bovina the dorsal surface of pleotelson presents stiff setae, a feature also present in C. bitari sp. nov., but in the latter antenna 2 only reaches pereonite 3. It is not known whether C. bovina presents penes.

Regarding C. zibrowiusi sp. nov., the main differences are: C. bitari sp. nov. has a depressed, flat body, while in C. zibrowiusi sp. nov. it is rounded and slightly depressed; antenna 2 reaches pereonite 3 in C. bitari sp. nov., but only pereonite 2 in C. zibrowiusi sp. nov.; the articles of antennal flagellum have one ( C. bitari ) or two ( C. zibrowiusi ) tufts of simple setae on the anterodistal angle; the pleonite 4 is clearly notched in C. bitari sp. nov., while in C. zibrowiusi sp. nov. it is not (or is only slightly) notched; and the uropods bear many lateral setae in C. bitari sp. nov., compared with few setae in C. zibrowiusi sp. nov. (in the remarks on C. zibrowiusi sp. nov. this feature is discussed in depth).

Figures

FIGURE 9. Cirolana bitari sp. nov. Holotype male [MZB 2016 - 3482]: A, body, dorsal View; B, body, lateral View; C, frontal lamina; D, antenna 1; E, antenna 2; F, apex of antenna 2 [female paratype MZB 2016 - 3483]; G, penes; H, uropod. Scale bars: A – B = 1 mm; C – G = 0.5 mm; H = 0.25 mm.

FIGURE 10. Cirolana bitari sp. nov. Holotype male [MZB 2016 - 3482]: A, mandible; B, maxilla 1, exopod; C, maxilla 2; D, maxilliped; E, pereopod 1; F, pereopod 3; G, pereopod 5; H, pereopod 7. Female paratype [MZB 2016 - 3483]: I, pleotelson, dorsal View; J, apex of pleotelson. Scale bars: A – D = 0.25 mm; E – H = 0.5 mm; I = 1 mm; J = 0.25 mm.

FIGURE 11. Cirolana bitari sp. nov. Holotype male [MZB 2016 - 3482]: A – E, pleopods 1 – 5. Scale bar: A – E = 0.5 mm.