Cirolana aldabrensis, Schotte & Kensley, 2005

Schotte, Marilyn & Kensley, Brian, 2005, New species and records of Flabellifera from the Indian Ocean (Crustacea: Peracarida: Isopoda), Journal of Natural History 39 (16), pp. 1211-1282 : 1220-1223

Cirolana aldabrensis sp. nov.

( Figures 5 , 6 )

Material examined

Holotype: USNM 280265 , one male (6.0 mm), Seychelles, sta K-AL-60, encrustations on intertidal boulders, Île Ésprit in Aldabra lagoon, 16 March 1985 . Paratypes: USNM 280266 , two females, one juvenile, sta K-AL-42, intertidal reef crest, Picard Island , Aldabra, 12 April 1983 .

Other material examined. USNM 280267 , four males, six juveniles , from four stations, coral rubble and low algal turf, Picard Island , Aldabra, intertidal to 10 m.

Description

Male. Body length about three times greatest width. All somites except telson and uropods dotted with red-brown chromatophores. Cephalon with very faint interocular furrow; rostrum not overlapping frontal lamina. Coxae 4–7 with entire oblique carinae and acute posterolateral angles. Pleonites 1 and 2 in lateral view overlapped by coxa of pereonite 7. Pleonites 4 and 5 with seven to eight tiny denticles on posterior margin. Pleotelson with dense mat of setules on dorsal surface in mature males; triangular, tapering to narrowly rounded apex bearing six spine-like setules, each separated by two plumose setae.

Antennular peduncle articles 1 and 2 fused but suture still visible, article 3 subequal in length to 1 and 2 combined; flagellum with 10–11 articles. Antenna extending to pereonite 4, flagellum with 25–27 articles.

Frontal lamina pentagonal, maximum width about two-thirds of length, lateral margins straight, converging very slightly toward base. Maxilla 1, maxilla 2 and mandible as figured. Maxillipedal endite with two coupling hooks and three plumose setae; article 5 of palp bearing 12 fringed setae of varying lengths amongst long, simple setae.

Pereopod 1, propodus with two simple, short setules on posterolateral margin; merus bearing four short, squat, wide setae on posterior margin, each bearing a short lash; ischium with very large, stout seemingly hollow seta on anterodistal margin. Pereopod 2, propodus with three flagellated setae on posterior margin; carpus bearing four robust and one slender setae at posterodistal margin; merus with six stout and two slender setae on posterior margin; ischium bearing one large and two smaller stout setae at posterolateral corner, one short and one long stiff setae at anterolateral angle. Pereopod 7, propodus with three pairs of short, double spine-like setae along anterior margin; carpus with nine serrate setae at posterolateral angle and five simple setae at anterolateral corner; merus having seven serrate setae and four simple setae at same angles; ischium with large, hollow seta, two shorter setae and one long, flagellated seta on posterolateral margin. Penes separate, elongate, about three times as long as wide, separated by about 10% of width of sternite 7.

Pleopod 1 peduncle with four coupling hooks and two plumose setae; endopod twothirds width of exopod, lateral margins straight. Pleopod 2, four coupling hooks and four plumose setae on peduncle; appendix masculina narrow, parallel-sided, extending beyond endopod by one-quarter of length, several setules set on lateral margin near acute apex. Pleopod 3 peduncle with four coupling hooks and four plumose setae, exopod suture complete. Pleopod 4 peduncle having four coupling hooks and three plumose setae, exopod suture complete. Pleopod 5 endopod lacking marginal setae, exopod with complete suture. Uropodal exopod shorter than pleotelson, lanceolate, bifid apex containing several long setae; lateral margin with five spine-like, flagellated setae and medial margin with four such setae set among numerous plumose marginal setae. Endopod with two short, spine-like lateral setae, five medial setae and bifid apex bearing long, slender setae; subequal in length to pleotelson.

Female. Similar to male except for sexual characters. Pleotelson nearly glabrous, denticles on pleonal margins lacking.

Remarks

The new species differs from its similar congener from Réunion Island, C. mascarenensis Müller, 1991 , by details of setation of the uropods and pleotelson: e.g. eight short, spinelike, flagellated setae on the pleotelsonic apex versus six in the new species, and seven and three such setae on lateral and inner margins of the exopod versus five and four, respectively, for C. aldabrensis . In Müller’s species the appendix masculina is relatively longer and penes are lacking; further differences can be seen in the type and number of strong setae on the pereopods, and in the lack of an overlapping rostrum. The prominent and elongate penes of C. aldabrensis represent a rare condition in the Cirolana parva complex of species.

Etymology

The species is named for the type locality.

Figures

Figure 5. Cirolana aldabrensis sp. nov. (A) Male, dorsal view; (B) male, lateral view; (C) uropod; (D) mandible; (E) apex of pleotelson; (F) maxilliped; (G) terminal palp article of maxilliped, enlarged; (H) frons; (I) maxilla 1; (J) penes; (K) pleopod 1; (L) maxilla 2.

Figure 6. Cirolana aldabrensis sp. nov. (A) Male pleopod 2; (B) pleopod 3; (C) pleopod 4; (D) apex of copulatory stylet; (E) pleopod 5; (F) pleopod 1; (G) dactyl of pereopod 1; (H) pereopod 2; (I) pereopod 7.