Accalathura kensleyi, King, Rachael A., 2008

King, Rachael A., 2008, A re-description of Accalathura crenulata (Richardson, 1901) from type material and the description of two new Accalathura species (Crustacea: Isopoda: Cymothoida), Zootaxa 1761, pp. 17-29 : 20-24

Accalathura kensleyi n. sp.

( Figs 2–3 )

Material examined. HOLOTYPE, USNM 211350 (ex 211350), ovigerous female, 27 mm, Carrie Bow Bay, Belize, Stn. AC-320, 321, 1–30 m, coll. 1979. PARATYPE, male, UNSM 1111737 (ex 211350), 25 mm, Carrie Bow Bay, Belize, Stn. AC-320, 321, 1–30 m, coll. 1979.

Other material. USNM 9121, off Cape San Antonio, Cuba, 9 m, coll. W. Nye, R/V Albatross, 7 May 1884, 1 immature female (20 mm). USNM 9581, off Cabo Catoche, Mexico, Stn. 2363, coll. R/V Albatross, 30 January 1885, 1 male (25 mm). USNM 211348, Carrie Bow Bay, Belize, 0–0.5 m, coll. B.F. Kensley, March 1980, males (9–25 mm), females (22–25 mm), immature females (15–20 mm), juveniles (5–7 mm). USNM 211349, Carrie Bow Bay, Belize, 0–0.5 m, coll. B.F. Kensley, March 1980, 1 immature female (20 mm), many juveniles (5–9 mm). USNM 1111738, Carrie Bow Bay, Belize, 1–30 m, coll. C. Reutzler, 1979, 2 immature females (12 mm), 3 juveniles (5–7 mm).

Diagnosis. Antenna 1 shorter than antenna 2; antenna 1 flagellum at least 2 times as long as peduncle; antenna 2 flagellum distinctly longer than the combined lengths of peduncular articles 3–5. Pereopod 1 propodus 2.2 times as long as broad (excluding ventral lobe). Pereopod 2 propodus 3 times as long as broad. Uropodal endopod narrow (2 times as long as broad) and tapered, with setae distributed laterally and distally. Telson broadest proximally, tapered to sub-acute point. Male pleopod 2 appendix masculina inflated sub-apically, narrowing to sub-acute point.

Description. Female. Head, pereon and pleon with dorsal pigmentation. Clusters of long setae present laterally on pereon at articulations of pereopods.

Antenna 1 shorter than antenna 2. Antenna 1 peduncle with articles 2 and 3 similar length, flagellum longer than peduncle, with more than 27 articles. Antenna 2 peduncular article 3 shortest, article 4 and 5 similar length, flagellum slightly longer than peduncle, with 34 articles.

Mandibular palp second article with six long setae, third article with longitudinal row of 31 short robust setae and one long apical robust seta with associated short single seta. Maxilla 1 slender and elongate with distal serration. Maxilliped palp, article 1 with two rows of long setae on inner edge, article 2 with seta at midlength and 18 long terminal setae; endite not reaching past article 2 of palp, with subterminal long seta.

Pereopod 1 basis and ischium with rows of long dorsal setae; merus broader than long and enclosing carpus, with long dorsal and ventral setae; carpus ventral margin with a cluster of robust setulate setae and long setae; propodus 2.2 times as long as broad, with proximal ventral lobe, ventral margin between lobe and dactylus excavated, with long simple setae, long tuberculate setae and short robust setulate setae along ventral margin and excavated section. Pereopod 2 basis and ischium with paired rows of long dorsal setae; merus as long as broad and enclosing carpus, with long dorsal and ventral setae; carpus with long ventral setae; propodus 3 times as long as broad, ventral margin with eight robust setae, six most proximal setae vary in lengths (fourth and fifth largest) and possess setule at mid-length, seventh and eighth most distal setae are trifid and bifid and lack setule at mid-length. Pereopod 3 basis and ischium with paired rows of long dorsal setae; merus longer than broad and covering carpus, with long dorsal and ventral setae; carpus with long ventral setae; propodus 4.6 times as long as broad, ventral margin with seven robust setae possessing setule at mid-length. Pereopods 4–7 becoming more elongate posteriorly, with numerous short robust setae on carpus and propodus.

Pleopod 1 exopod 2.2 times as long as broad, with at least 45 distal long plumose setae; endopod shorter than exopod, 4.5 times as long as broad, with 10 distal long plumose setae. Pleopods 2–5 shorter than pleopod 1, exopod and endopod similar size, endopod with around 12 long plumose setae, exopod with 12–16 long plumose setae.

Uropodal peduncle inner distal margin raised, outer distal margin acute and distinctly raised, endopod distally rounded, 2 times as long as broad, with setae distributed laterally and distally. Uropodal exopod reaching past peduncle of endopod, dorsal and ventral margins with long plumose and simple setae (simple setae concentrated apically). Telson broadest proximally, 2.6 times as long as broad, tapered to sub-acute point, with long simple setae distally, distal 1/3 margin with some slight serration between setae.

Male. (Sexually dimorphic characters) Antenna 1 peduncle similar to female, flagellum with at least 41 articles, articles 2–18 with dense clusters of aesthetascs and setae or in larger males (> 20 mm) with aesthetascs less abundant or lacking. Antenna 2 peduncle similar to female, flagellum with at least 52 articles.

Pereopod 1 propodus varying with size of adult male: propodus robust, with proximal lobe (9 mm male), without proximal lobe (> 15 mm males). Pereopod 2 propodus varying with size of adult male: propodus as for female (9 mm males), with developed proximal lobe (> 15 mm males). Pereopod 3 propodus varying with size of adult males: without proximal lobe (9 mm males), with proximal lobe (> 20 mm males).

Appendix masculina inflated sub-apically and narrowing to a terminal sub-acute point. Size of appendix masculina (relative to endopod and exopod rami) varies with size of adult male: in smaller males appendix masculina reaches past rami, in larger males similar in length to rami.

Distribution. Belize (type locality); Cuba; Yucatan Peninsula of Mexico; US Virgin Islands ( Barnard, 1925) (see Discussion).

Etymology. This species is named for Dr. Brian Kensley, formerly of the National Museum of Natural History (Smithsonian), Washington D.C., in tribute to his substantial work on anthuroid isopods.

Remarks. The males of A. kensleyi n. sp. exhibit marked secondary sexual characters similar to those that have been noted in two other species of Accalathura ( A. normani Nierstrasz, 1941 from the Flores Sea and A. zoisia Poore & Lew Ton, 1990 from Western Australia). Specifically, in A. kensleyi n. sp. mature males (those with a developed appendix masculina) exist over a range of sizes, from 9 mm to 25 mm, exhibiting differences in the morphology of the antennae, anterior pereopods and appendix masculina, compared to the females and among male size classes (detailed in the species description).

Figures

FIGURE 2. Accalathura kensleyi n. sp., USNM 211350, holotype female, 27 mm (circles show setal inserts, where setae have been removed for clarity). A, dorsal view of head and pereonite 1; B, pereopod 1 (with enlargement of long tuberculate seta at left and robust setulate seta at right); C, pereopod 2; D, pereopod 3; E, maxilliped; F, mandible; G, pereopod 4 (dactylus damaged); H, telson; I, uropodal peduncle and endopod; J, uropodal exopod; K, distal end of pereopod 7.

FIGURE 3. Accalathura kensleyi n. sp. USNM 211350, paratype male, 25 mm (circles show setal inserts, where setae have been removed for clarity). A, pereopod 1 (15 mm TL); B, pereopod 1 (> 20 mm TL); C, distal end of pereopod 2 (15 mm TL); D, distal end of pereopod 2 (> 20 mm TL); E, distal end of uropodal peducle and endopod (> 20 mm TL); F, antenna 1; G, antenna 2; J, pleopod 2 with appendix masculina. USNM #####, holotype female, 27 mm, H, pleopod 1; I, pleopod 2 (peduncle missing).