Cassidinidea clarkae, 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 : 1241-1245

Cassidinidea clarkae sp. nov. ( Figures 17 , 18 )

Material examined

Holotype: USNM 280290 , one male, 2.0 mm, intertidal mudflat with green algae, Harbour View Guesthouse, Mahe´, Seychelles, coll. J. Clark, 1 May 1984 . Paratypes: USNM 280291 , two males, two ovigerous females, one female, same data as holotype .

Description

Male. Body reticulate brown-red pigment on all segments including base of uropodal endopods. Pereonites smooth. Epistome rectangular, twice as wide as long, fairly straightsided with incurving extensions posteriorly. Pleonite 7 and pleon with few scattered tubercles especially in male. Pleotelson with four very weak longitudinal carinae, not tuberculate, medial two seeming to converge at base of segment; apex of pleotelson truncate.

Antennal flagellum with seven articles; antennular flagellum with three to four. Maxilla 1 and 2 and mandible as figured. Pereopod 1 having two stout fringed setae at mid-length of propodus; pereopod 2 with scattered simple setules and two robust setae on propodus. Pereopod 7 with nine very robust and two slender setae at articulation of carpus. Pleopod 1 endopod reduced in width, indented distally, margins of both rami with simple and plumose setae. Pleopod 2, appendix masculina long, slender, extending beyond endopod by one-third total length, posterior one-third with tiny setules on margins. Pleopod 3 with complete suture on endopod. Pleopods 4 and 5 as shown, few if any marginal setae present. Fused penial process more than three times longer than wide.

Ovigerous female. As for male, except sexual characters, somewhat larger in size. Internal pouches absent.

Remarks

This animal is tentatively separated from another Indian Ocean species, C. quadricarinata Pillai, 1954 , which was not examined. The latter’s dorsum is furnished with ‘‘four distinct longitudinal rows of tubercles giving the animal a quadricarinate appearance’’. The rows on the pleotelson of C. clarkae , which are lacking on the dorsum, are not tuberculate but very low and smooth. Based on Pillai’s illustrations, C. quadricarinata bears one large biserrate seta on the propodus of pereopod 1 whereas the new species has two; pereopod 7 is much more setose marginally than in C. clarkae . These two species both possess an apically truncate pleotelson. Cassinidea monodi ( Barnard, 1951) , recently transferred from Dies by Bruce (1994b), also shows four low, rounded keels on the pleotelson but is distinguished by its bluntly rounded apex.

Etymology

The species is named for its collector, Janice Clark Walker, formerly of the Department of Zoology, NMNH.

Genus Cymodoce Leach, 1814

Restricted synonym. Cymodoce Leach 1814, p 433 ; Dumay 1972a, 1972b, 1972c, 1972d; Harrison and Holdich 1984, p 302.

Diagnosis

Cephalon, pereon and pleon lacking dorsal extensions. Pleon bearing two, long, straight parallel sutures at each side extending to postero-lateral angle. Pleotelsonic apex with marked notch bearing median tooth. Pleopods 4 and 5 with branchial pleats on endopods only. Sexual dimorphism obvious. Uropodal endopod in male thickened, not reduced, often lanceolate; exopod lamellar. Penes long, slender, separate to base. Appendix masculina arising basally and extending well beyond apex of pleopodal endopod. Ovigerous female mouthparts metamorphosed; brood pouch formed by four pairs of oostegites arising from sternites 1–4 and overlapping at midline; brood held in internal pouches. Uropodal rami in female both lamellar.

A tentative key to recognized species of Cymodoce found in the Indian Ocean is presented below, based on morphology of adult males. Since the genus is in need of extensive revision ( Harrison and Holdich 1984), those species whose generic standing is in question are not included in the key but listed here: C. acanthiger Barnard, 1914 ; C. africana Barnard, 1914 ; C. alia Kensley, 1975 ; C. amplifrons ( Stebbing, 1902) ; C. cavicola Barnard, 1920 ; C. cryptodoma Barnard, 1920 ; C. daviae Kensley and Buxton, 1984 ; C. excavans Barnard, 1920 ; C. falcata Barnard, 1920 ; C. lis Barnard, 1955 ; C. madrasensis ( Srinivasan, 1959) ; C. picta Brocchi, 1875 ; C. radiata Barnard, 1957 ; C. setulosa ( Stebbing, 1902) ; C. tetrahele Barnard, 1920 ; C. umbonata Barnard, 1914 ; C. uncinata Stebbing, 1902 ; C. valida ( Stebbing, 1902) ; C. velutina Kensley, 1975 .

Key to species of Cymodoce from the Indian Ocean 1. Adult male pleotelson with large, obvious, submedian boss, usually setose,

anterior to median apical lobe............... 6 – Adult male pleotelson lacking submedian boss anterior to median lobe... 2

2. Pleon with two extensions or large tubercles on posterior margin..... 3 – Pleon lacking two extensions or tubercles on posterior margin......

................. C. erythraea Nobili, 1906

[Red Sea]

3. Pleotelson with median apical lobe bifid..... C. comans Barnard, 1914 [False Bay to Natal, South Africa]

– Pleotelson with median apical lobe not bifid........... 4

4. Uropodal exopod extending beyond apex of pleotelson by 50% of length, much longer than endopod; pleotelson with several conical and bifid tubercles...................... C. alis Barnard, 1955 [False Bay to Port Elizabeth, South Africa]

– Uropodal rami subequal in length.............. 5

5. Median lobe of pleotelsonic apex tapering to narrowly rounded apex; lateral incisions deep, equal to one-third of pleotelson in length.. C. fuscina sp. nov. [Persian Gulf]

– Median lobe of pleotelson short, very rounded apically; lateral incisions shallow.............. C. natalensis Barnard, 1920 [Algoa Bay to Natal, South Africa]

6. Median apical lobe of pleotelsonic apex considerably longer than lateral lobes.......................... 7 – Median apical lobe of pleotelsonic apex subequal to or slightly longer than lateral lobes....................... 8

7. Median lobe coplanar with lateral lobes; notches on either side of median lobe very shallow; uropodal endopod extending beyond apex of pleotelson by more than 25%............... C. bicarinata Stebbing, 1904 [ Maldive Islands; Sri Lanka, Zanzibar]

– Median lobe overlying telsonic incision; uropodal endopod barely extending beyond apex of pleotelson........... C. lirella sp. nov. [ Mahe, Seychelles]

8. Pleotelson with two curving carinae in proximal half.........

................. C. richardsoniae Nobili, 1906 [Red Sea]

– Pleotelson lacking such carinae............... 9

9. Uropodal endopod extending beyond pleotelsonic apex by 40–50% of length.

........................ 10 – Uropodal endopod barely surpassing apex of pleotelson....... 11

10. Submedian boss bearing antero-median spine; pleotelsonic tubercles discrete, single.............. C. pelsarti Tattersall, 1922 [Western Australia and Queensland]

– Antero-median spine on submedian boss lacking; some tubercles on pleotelson fused into ridges............ C. longistylis Miers, 1884 [Torres Strait, Australia; Nicobar Islands; India; Thailand]

11. Uropodal exopod extending beyond apex of pleotelson by much less than 50% of length............. C. zanzibarensis Stebbing, 1910a [ Zanzibar; Mozambique]

– Uropodal exopod extending beyond apex of pleotelson by at least 50% of length............ C. pilosa (H. Milne Edwards, 1840) [Gulf of Suez; Mediterranean]

Figures

Figure 17. Cassidinidea clarkae sp. nov. (A) Male, dorsal view; (B) male, lateral view; (C) frontal lamina; (D) antenna; (E) antennule; (F) pleotelson; (G) penes; (H) left mandible; (I) right mandible; (J) maxilla 1; (K) maxilla 2; (L) maxilliped.

Figure 18. Cassidinidea clarkae sp. nov. (A) Pereopod 2; (B) pereopod 7; (C) pleopod 1; (D) pereopod 1; (E) pleopod 3; (F) pleopod 4; (G) male pleopod 2; (H) pleopod 5.