Colopisthus cavalier, MOORE & BRUSCA, 2003

MOORE, WENDY & BRUSCA, RICHARD C., 2003, A monograph on the isopod genus Colopisthus (Crustacea: Isopoda: Cirolanidae) with the description of a new genus, Journal of Natural History 37 (11), pp. 1329-1399 : 1349-1355

Colopisthus cavalier new species

(figures 10–14)

Material examined. H  , female ( USNM 285288 ) and six female paratypes ( USNM 285289 ); Barbuda, Spanish Point, intertidal beach wrack and live Porites ; Bredin Expedition 1958, Station 112a-58, collected by Smitt and Shuster ( USNM 217237 ) .

Diagnosis. Lateral margins of cephalon and pereonite 1 with crenulations. Coxae 4–7 visible dorsally. Antenna 1 flagellum three-articulate. Antennae 2 flagellum sixarticulate. Pleon with one free pleonite and two fused pleonites (suture visible only in lateral view). Maxilliped endite with four circumplumose setae and three coupling setae. P-1 to P-3 merus with four to six molariform setae on inferior margin. Carpus of P-1 with four connate spines on inferior margin; P-2 and P-3 with three to five molariform setae and cuticular tubercles on inferior margin. Propodus of P-1 and P-2 with two complex setae and four or five connate spines. Pl-3 exopod with partial transverse suture. Uropodal exopod with two robust setae.

Description of female

Head. Lateral margins of cephalon and pereonite 1 with crenulations.

Antennae. Antenna 1 peduncular articles 1–3 with biplumose setae, article 3 longest and narrowest, article 4 with slender and biplumose setae; flagellum threearticulate, first article much longer than distal two articles, all flagellar articles with slender setae and jointed aesthetascs, terminal article with biplumose seta. Antennae 2 peduncular articles 2–3 wider than long with slender setae only; article 4 subquadrate with biplumose and slender setae; article 5 longer than wide with three biplumose, one palmate and approximately 11 slender setae; flagellum six-articulate, all longer than wide, all with cluster of slender setae in anterior-distal region.

Maxilliped. Endite with four circumplumose setae and three coupling setae. Palp article 1 medial margin with fine and slender setae; article 2 much wider than long, medial margin with slender setae; article 3 subquadrate with jointed slender setae on lateral and medial margins, article 4 subquadrate with one jointed slender seta on disto-lateral angle, two uniserrate and approximately four jointed slender setae on distal medial angle; terminal article length greater than width and with approximately four slender, one biplumose and two uniserrate apical setae.

Maxillae. Maxilla 1 lateral lobe with one stout, seven forked and three uniserrate setae; medial lobe with two slender and three stout biplumose setae. Maxilla 2 outer lobe with three uniserrate apical setae, fine setae on lateral margin; medial lobe with four uniserrate setae; gnathal lobe apical margin with one large circumplumose, five stout biplumose and two slender setae; clusters of fine setae on medial and lateral margins.

Mandible. Spine row with 11 large spines; molar process with approximately 16 small acute marginal spines; proximal palp article longer than wide with one slender seta on lateral margin; middle article with three slender, seven biserrate and four unequally biserrate setae; distal article with nine biserrate setae.

Pereopods 1–3. Ischium with one or two stout setae on inferior margin and one stout seta on superior-distal angle; P-3 with molariform seta near inferior-distal angle. Merus with cuticular tubercles on inferior margin, P-2 and P-3 with two molariform setae and a cluster of stout setae on distal angles; distal margin deeply incised (notched) on anterior surface. Carpus subtriangular, inferior margin much longer than superior margin; with cluster of stout setae on inferior distal angle; P-1 with four connate spines on inferior margin; P-2 and P-3 with three to five cuticular tubercles on inferior margin. Propodus with complex setae and connate spines on inferior margin as figured; P-1 and P-2 with two complex setae and four or five connate spines; P-3 with two complex setae and no connate spines; P-1 to P-3 superior distal angle with two slender setae, P-2 also with a biplumose seta.

Pereopods 4–7. Basis with two biplumose setae at inferior distal angle. Ischium with two to four clusters of stout setae on inferior margin; P-4 with cuticular tubercles on inferior distal angle; P-5 and P-7 with two or three robust setae at superior-distal angle. Carpus of P-5 with one biplumose seta on anterior-distal margin, P-6 with two biplumose setae on anterior-distal margin and one biplumose seta on superior-distal angle, P-7 with seven biplumose setae on anterior-distal margin and approximately five long biplumose setae at superior-distal angle. Propodus superior-distal angle with stout and biplumose setae; P-4 to P-6 posteriordistal margin with one stout seta; inferior distal angle with two stout setae on P-4 and P-5 and one stout seta and one reduced complex seta on P-6 and P-7.

Pleopods. Pl-1 to Pl-4 peduncle with three coupling setae on medial margin. Pl-3 to Pl-5 lateral margin of peduncle with one stout seta. Pl-3 exopod with partial transverse suture, Pl-4 and Pl-5 exopod with complete transverse suture. P1-1 to Pl-5 exopods with fine setae on proximo-lateral angle. Pl-1 to Pl-3 endopods with fine setae on proximo-medial angle. Pl-1 to Pl-4 endopods with approximately five PMS; exopods with approximately 13–16 PMS. Pl-5 endopod subovate, without setation; exopod with approximately eight PMS.

Uropod. Endopod with slender and palmate setae; two robust setae on medial margin and one robust seta on lateral margin; apex broadly rounded, with approximately four long slender setae. Exopod with slender setae and two robust setae on medial margin; apex rounded, with approximately three long slender setae; lateral margin with a continuous row of short slender setae; proximal lateral margin with dorsal fold.

Distribution

So far known only from Spanish Point, Barbuda, where it was collected from intertidal beach wrack and live Porites (a scleractinian coral).

Remarks Known only from females.

Etymology

This species is named after Cavalier rum, a light golden rum of the islands of Barbuda and Antigua.