Cirolana zibrowiusi, Castelló, 2017

Castelló, José, 2017, New and little-known species of isopods (Crustacea, Isopoda) from the eastern Mediterranean, Zootaxa 4311 (2), pp. 151-182 : 169-177

Cirolana zibrowiusi sp. nov.

( Figs 12–16 )

Material examined. Holotype: ovigerous female, 8.2 mm, sample 5M23, station 12: Beirut Airport pier, Lebanon, 33°50'32”N, 35°28'48”E, 3–11 m, pillar of the breakwater, no ecological data, G. Bitar & H. Zibrowius coll., 25 Sept. 2002 ( MZB2016-3484, 21 slides).

Paratypes: male, 5.9 mm, sample 5M23, same locality as holotype ( MZB2016-3485, 20 slides); ovigerous female, 7.6 mm, sample 5M23 , same locality as holotype ( MZB2016-3486 ) ; juvenile, 3.9 mm, sample 5M23, same locality as holotype ( MZB2016-3487 ) ; female, 7.2 mm, sample 5M13, stn. 9: Beirut inside harbor, quay 60 ( MZB2016-3488 ) ; ovigerous female, 10.2 mm, sample 5M51, stn. 12: Beirut Airport pier ( MZB2016-3489 ), depth: between 3 and 11 m. G. Bitar & H. Zibrowius coll., between 16 Sept. 2002 and 16 July 2003.

Diagnosis. Body rounded, slightly depressed, about 3.7 times as long as wide. Dorsal surface of body without tubercles. Posterior margin of pereonites 5–7 and pleonites 2–5 with denticles or nodules. Stiff setae on pereonite 7, pleonites 2–5 and pleotelson. Frontal lamina pentagonal with rounded angles. Antenna 2 reaching half of pereonite 2. Articles of antennal flagellum with two tufts of simple setae on anterodistal angle. Penes flat, well developed.

Description of holotype [MZB2016-3484]. Body about 3.7 times as long as wide, moderately depressed, widest at pereonite 5. Cephalon with dorsal furrows and with anterior margin rounded, not produced. Frontal lamina pentagonal with rounded angles, not visible in dorsal view, separating antennular bases. Eyes lateral, rounded, with about 50 ommatidia; slightly covered by pereonite 1. Pereonites 1–6 subequal in length; pereonite 7 shortest. Pereonites with dorsal transverse furrow, especially conspicuous in pereonites 1, 6 and 7. Posterior margin of pereonites 1–3 without denticles or nodules, which are present in pereonites 4–7, increasingly further back. Stiff setae on posterior margin of pereonite 6 and dorsal surface of posterior half of pereonite 7. Coxae 2–3 with posterior margin rounded; coxae 4–7 with posterior margin oblique; coxae 4–7 with oblique carina. Pleonite 1 largely concealed by pereonite 7. Pleonites 2–5 subequal in length. Pleonites 2–4 with concave posterior margin, especially last one. Posterior margin of pleonites 2–5 with nodules and stiff setae, also present dorsally. Pleotelson triangular with slightly rounded margins; apex acute with 8 robust setae interspersed with simple setae (also in paratype male 5.9 mm (sample 5M23) [MZB2016-3485]). Dorsal surface of pleotelson without nodules, entirely covered by stiff setae (also in paratype male 5.9 mm (sample 5M23) [MZB2016-3485]), not as robust as 8 apical setae.

Antenna 1 with peduncle of 4 articles; article 2 slightly longer than article 1; article 3 longest; article 4 minute; flagellum of 16 articles; articles 1–15 with aesthetascs; final article with 3 simple setae. Antenna 1 reaches one half of pereonite 1. Antenna 2 with peduncle of 5 articles progressively increasing and decreasing their length and section respectively; 2–3 simple setae on anterodistal angle of articles 2–5; 2 sensory setae on distal margin of article 5; flagellum with 22 articles; two tufts of simple setae on anterodistal angle of articles; final article with 2 simple setae. Antenna 2 reaching half of pereonite 2.

Mandible with incisor with 3 cusps, external one longest; molar process with continuous row of 21 teeth (left mandible) placed not on margin but on one side; opposite side with numerous thin setae near complete margin of lamina; spine row with 4 robust setae (left mandible); palp with 3 articles; articles 2–3 setose; apical article with 17 pectinated setae. Maxilla 1 exopod with 8 stout setae and 3 short setae; endopod lost during dissection. Maxilla 2 inner lobe with 8 plumose setae and 7 simple setae; medial lobe with 12 simple setae; outer lobe with 4 simple setae. Maxilliped with endite extending to mid-point of palp article 2, distally with coupling hook and 6 plumose setae; palp article one with 2 mediodistal setae; article 2 with seta on externodistal angle, and 8 setae on internodistal angle; article 3 with 3 setae on external margin, and 12 setae on internodistal angle; article 4 with 2–3 setae on external margin, and 10–12 setae (one of them, pectinated) on internodistal angle; article 5 with 3 setae on external margin, and about 10 setae at apex (2 of them pectinated); epipod oval, extending half of length of palp article 3, with some 25 plumose marginal setae.

Pereopod 1 basis stout with 2 setae on posterodistal angle; ischium with stout bifid seta on anterodistal angle, 5–6 setae near the tubercular distal margin, blunt short seta on posterodistal angle (medial side); merus with stout bifid seta on anterodistal angle, 6 setae on distal margin, 5 tubercular bifid blunt setae on posterior margin, and robust pectinated seta between blunt second and third setae placed on medial side; carpus triangular laterally, with seta on posterodistal angle, tubercular, and 2 more setae on distal margin; propodus with seta on anterodistal angle, and 2 small setae on anterior margin, posterior margin toothed with 2 robust setae (last of them stoutest and placed on posterodistal angle) and 3 setae on posterodistal angle on medial side; a ridge of 7 teeth and 2 small setae on external side, parallel to posterior margin. Pereopod 2 less robust than pereopod 1; basis with 5 setae on posterodistal angle; ischium with stout bifid seta on anterodistal angle, 3 setae near distal margin, not tubercular, 3 short setae on proximal section and 2 tubercular bifid blunt setae near distal angle of posterior margin; merus with 2 stout bifid setae on anterodistal angle, near another stout bifid seta on distal margin, 5 stout bifid setae and 2 setae on posterodistal angle, and 4 stout bifid setae on posterior margin, tubercular, near seta on external side; carpus with seta on posterodistal angle, near 2 setae on distal margin; propodus with 2 setae on anterodistal angle, stout bifid seta wrapped by two groups of 2 (internal side) and 3 (external side) setae on posterodistal angle, and 2 stout bifid setae on smooth posterior margin. Pereopod 3 stouter than pereopod 2 although smaller in size; basis with 5 setae on posterodistal angle; ischium with 2 stout bifid setae on anterodistal angle, near another bifid seta on the distal margin, 2 setae on the distal margin, 2 stout bifid setae on posterodistal angle (internal side), and 2 setae on posterior margin; merus with 2 stout bifid setae on anterodistal angle, near pectinated seta on distal margin (internal side), posterior margin with two groups of 4 (distal angle) and 5 stout pectinated bifid setae; carpus with seta on anterodistal angle, seta on distal margin, near the posterodistal angle, with seta and 3 pectinated bifid setae; propodus with 4 setae on anterodistal angle, 2 setae and stout bifid seta on posterodistal angle, and 2 stout bifid setae on posterior margin. Pereopods 4–7 similar but becoming longer posteriorly; basis with row of short simple setae on external side (2, 3, 3, and 5 setae on pereopods 4–7 respectively), and a group of setae on posterodistal angle (pereopod 4: 2 simple setae and 2 bifid setae; pereopod 5: 3 simple setae and 2 bifid setae; pereopod 6: 5 simple setae; pereopod 7: 5 simple setae and one pectinated seta); ischium with 4 (pereopod 4), 9 (pereopod 5), 8 (pereopod 6) or 9 (pereopod 7) setae (bifurcated or pectinated) on anterodistal angle, posterior margin with three groups of 2, 4 and 4 (pereopod 4), 2, 3 and 4 (pereopod 5), 2, 4 and 5 (pereopod 6), and 2, 2 and 3 (pereopod 7) simple, bifid or pectinated setae, sometimes becoming robust setae on posterodistal angle; merus with 5 (pereopod 4), 6 (pereopod 5), 6 (pereopod 6), and 9 (pereopod 7) bifid or pectinated setae on anterodistal angle, posterior margin with two (pereopods 4–6) or three (pereopod 7) groups of 8 and 10 (pereopod 4), 6 and 10 (pereopod 5), 5 and 10 (pereopod 6) and 2, 3 and 8 (pereopod 7, bifid or robust setae placed on tubercular ridges) bifid or robust setae; carpus with 3 (pereopod 4), 3 (pereopod 5), 10 (pereopod 6) and 11 (pereopod 7) bifid or pectinated setae on anterodistal angle, posterior margin with three groups of 2, 6 and 8 (pereopod 4), 2, 5 and 10 (pereopod 5), 2, 4 and 10 (pereopod 6), and 2, 4 and 10 (pereopod 7) bifid, robust or pectinated setae; propodus without setae (pereopods 4, 5 and 7) or with 3 small setae on anterior margin (pereopod 6), anterodistal angle with 3 simple setae (pereopod 4), 5 simple, sensory or bifid setae (pereopod 5), 6 simple, sensory or bifid setae (pereopod 6) and 6 simple or bifid setae (pereopod 7), posterior margin with four groups of one, 2, 3 and 2 (pereopod 4), 2, 2, 2 and 3 (pereopod 5), 2, 3, 3 and 3 (pereopod 6) and one, 2, 3 and 3 (pereopod 7) bifid or robust setae; in addition, one simple long seta on posterodistal angle on pereopod 7.

In male paratype 5.9 mm (sample 5M23) [MZB2016-3485], penes present, flat, well developed.

Pleopod 1 rami subequal in length; medial margin of peduncle with 4 coupling-hooks, and 3 plumose setae; external margin with robust seta; endopod and exopod with 14 and 35 plumose setae respectively; exopod with robust seta on proximolateral angle. Pleopod 2 endopod slightly longer than exopod; medial margin of peduncle with 3 coupling-hooks, and 3 plumose setae on the margin; external margin with robust seta; endopod and exopod with 15 and 37 plumose setae respectively. In male paratype 5.9 mm (sample 5M23) [MZB2016-3485], peduncle with seta on triangular boss and 2 setae on margin, appendix masculina robust, curved, surpassing length of endopod and reaching two-thirds 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 rami subequal in length; exopod with incomplete suture. Sympod of pleopods 3–4 with 3 coupling-hooks, and 4 plumose setae on inner margin; external margin with robust seta; endopod and exopod with 13 and 43 plumose setae (pleopod 3), and with 9 and 41 plumose setae (pleopod 4). Pleopod 5 with robust seta on external margin of sympod; endopod without setae and 41 plumose setae on exopod.

Uropods clearly surpassing apex of pleotelson; endopod longer than exopod. Peduncle ventrolateral angle with 6 robust setae. Endopod length:width ratio 2.1; both margins serrated; outer margin with 5 stout setae interspersed with plumose (proximal section) and bifid (distal section) setae, both absent in proximal half; apex bifid with tuft of bifid setae and 3 longer simple setae; inner margin with 7 stout setae interspersed with plumose setae, both absent in proximal half. Exopod length:width ratio 2.6; lateral margin slightly serrated with 6 stout setae interspersed with bifid setae; apex bifid with tuft of bifid setae and 4 longer simple setae; internal margin serrated with 4 stout setae interspersed with plumose setae, absent in proximal half.

Color in alcohol yellowish brown, without cromatophores.

Variation. Female 7.2 mm, ovigerous female paratype 7.6 mm, and ovigerous female 10.2 mm with body less depressed than in the holotype; the section of the body is circular or slightly compressed at the level of the first pereonites.

Antenna 1 reaches the end of pereonite 1 and antenna 2, and the half of pereonite 2 in the male paratype 5.9 mm. Pleonite 1 is totally concealed by the pereonite 7 in the female 7.2 mm, the ovigerous female paratype 7.6 mm, and the juvenile paratype 3.9 mm, and only slightly visible in the male paratype 5.9 mm.

Absence of denticles or nodules on pereonites 4–7 and pleonites 2–5 in the female 7.2 mm, the male paratype 5.9 mm, and the juvenile paratype 3.9 mm.

Absence of setae on the surface of pleotelson in the juvenile paratype 3.9 mm.

Etymology. The species is dedicated to Dr. Helmut Zibrowius, who entrusted me with the study of the isopods from Lebanon collected during the CEDRE campaigns and has waited patiently for the results.

Remarks. According to Bruce's (1986) criteria, C. zibrowiusi sp. nov. can be included in the “tuberculate group” although it has nodules rather than dorsal tubercles. It is related to C. manorae , which presents nodules and also tubercles on pleonite 5 and the pleotelson ( Fig. 17 ); and also to C. bovina , which furthermore shows pleotelson entirely covered by stiff setae like C. zibrowiusi sp. nov..

Cirolana zibrowiusi sp. nov. can be distinguished from the related species ( C. bitari sp. nov., C. bovina , C. manorae ) by flat penes (different from C. manorae ), antenna 2 reaching pereonite 2 (different from C. bitari sp. nov. and C. bovina ), flagellum of antenna 2 with two tufts of simple setae on the anterodistal angle (different from C. bitari sp. nov.), a relatively cylindrical body (different from C. bitari sp. nov., C. bovina , and C. manorae ), pleonite 4 not or only very slightly notched (different from C. bitari sp. nov.), pleotelson with dorsal stiff setae (different from C. manorae ), and uropodal margins with few setae (different from C. bitari sp. nov.).

The differences in uropodal setation between C. bitari sp. nov. and C. zibrowiusi sp. nov. are summarized as follows: Endopod inner margin.- C. bitari : setae absent in the proximal third; C. zibrowiusi : setae absent in the proximal half; Endopod outer margin.- C. bitari : 9 robust setae, setae absent in the proximal third; C. zibrowiusi : 5 robust setae interspersed with bifid setae, setae absent in the proximal half; Exopod inner margin.- C. bitari : 3 robust setae, setae absent in the proximal fifth; C. zibrowiusi : 4 robust setae, setae absent in the proximal half; Exopod outer margin.- C. bitari : 6 robust setae, plumose setae on the entire length; C. zibrowiusi : 6 robust setae, bifid setae on the entire length.

Figures

FIGURE 12. Cirolana zibrowiusi sp. nov. OVigerous female 10.2 mm [MZB 2016 - 3489]: A, body, dorsal View; B, body, lateral View. Scale bar: A – B = 1 mm.

FIGURE 13. Cirolana zibrowiusi sp. nov. Holotype female [MZB 2016 - 3484]: A, frontal lamina; B, distal end of body, dorsal View; C, apex of pleotelson; D, antenna 1; E, antenna 2; F, uropod. Scale bars: A, C – F = 0.5 mm; B = 1 mm.

FIGURE 14. Cirolana zibrowiusi sp. nov. Holotype female [MZB 2016 - 3484]: A, mandible; B, maxilla 1, exopod; C, maxilla 2; D, maxilliped; E, pereopod 1; F, pereopod 3; G, pereopod 5; H, pereopod 7. Scale bar: A – H = 0.5 mm.

FIGURE 15. Cirolana zibrowiusi sp. nov. Holotype female [MZB 2016 - 3484]: A – E, pleopods 1 – 5. Scale bar: A – E = 0.5 mm.

FIGURE 16. Cirolana zibrowiusi sp. nov. Paratype male 5.9 mm [MZB 2016 - 3485]: A, body, dorsal View; B, body, lateral View; C, antenna 1; D, antenna 2; E, pleopod 2. Scale bars: A – B = 1 mm; C – E = 0.5 mm.

FIGURE 17. Cirolana manorae Bruce & JaVed, 1987. OVigerous female from station 12 (Beirut Airport pier, Lebanon) (sample 5 M 23): A, distal end of body, dorsal View; Another oVigerous female from the same station (sample 5 M 23): B, distal end of body, dorsolateral View. Scale bar: A – B = 1 mm.