Colopisthus parvus Richardson, 1902

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 : 1355-1364

Colopisthus parvus Richardson, 1902

(figures 15–22)

Colopisthus parvus Richardson, 1902: 289 , pl. XXXVIII, figures 33–36; Richardson 1905: 137, figure 119; Kensley and Schotte, 1989: 147, figure 66A; Kensley, 1994: 319.

Not Colopisthus parvus . Monod, 1952; Menzies and Glynn, 1968; Müller, 1993: figures 72–96.

Type material examined. (1) Syntypes (co-types), females ( USNM 24867 , Acc. No. 37555): Bermuda, Bailey Bay , low water in coralline algae; Yale University Expedition 1898; collected by A. E. Verrill.

Other material examined. (2) YPM 3338 ; Bermuda; collected by A. E. Verrill; one female specimen. (3) YPM 3341 ; Bermuda, St George’s Parish, Castle Harbor, Waterloo ; A. E. Verrill Bermuda Expedition 1901; one male specimen. The following voucher specimens from Kensley (1994). (4) YPM 9574 ; Bermuda, Devonshire Bay ; 1985, collected by M. F. Gable; one female and one juvenile specimen. (5) YPM 9684 ; Bermuda, Devonshire Bay , 0.3 m depth; 1988; collected by E. A. Lazo-Wasem; 18 female, five male and 12 juvenile specimens. (6) YPM 9685 ; Bermuda, St George’s Parish ; 1988, collected by E. A. Lazo-Wasem and J. Hamilton; one male specimen. (7) YPM 9632 ; Bermuda, Hamilton Parish, Shelly Bay , 0.3 m depth; 1987, collected by M. F. Gable; three female specimens .

Diagnosis. Pleon of female with two free pleonites; males with three free pleonites. Lateral margins of pereonite 1 without crenulations or with weak crenulations. Antenna 1 flagellum three-articulate. Antennae 2 flagellum six-articulate. Maxilliped endite with five circumplumose setae and two coupling setae. Merus of P-1 to P-3 with two or three molariform setae on inferior margin. Carpus of P-5 with one biplumose seta on anterior-distal margin, P-6 with three biplumose setae on anteriordistal margin, P-7 with 10 biplumose setae on anterior-distal margin. Pl-3 exopod with partial transverse suture.

Description of female

Antennae. Antenna 1 peduncular article 1 with slender and palmate setae; articles 2–3 with slender setae only; article 3 longest and narrowest; article 4 without setae; flagellum three-articulate, first article much longer than distal two articles, all flagellar articles with slender setae and jointed aesthetascs. Antennae 2 peduncular article 1 minute, articles 2 and 3 with slender setae, articles 4 and 5 with biplumose and slender setae on distal margin; flagellum six-articulate, all with clusters of slender setae in the anterior-distal region.

Maxilliped. Endite with five circumplumose setae and two coupling setae. Palp article 1 medial margin with fine and slender setae; article 2 lateral margin with slender setae and medial margin with fine and slender setae; articles 3 and 4 with slender setae on lateral and medial margins, article 4 with one uniserrate seta on distal medial angle; terminal article subquadrate, with slender and uniserrate apical setae.

Maxillae. Maxilla 1 lateral lobe with one stout, six forked and four uniserrate setae; medial lobe with one small slender and three stout biplumose setae. Maxilla 2 outer lobe with three uniserrate setae, fine setae on lateral margin; medial lobe with four uniserrate setae; gnathal lobe with one slender seta at base (below outer lobe), fine setae on medial margin; apical margin with one large circumplumose, five stout biplumose and slender setae.

Mandible. Spine row with 14 large spines; molar process with approximately 20 small acute marginal spines; proximal palp article with one slender seta on lateral margin; middle article with one slender, seven biserrate and four unequally biserrate setae; distal article with 10 biserrate setae.

Pereopods 1–3. Ischium on P-1 and P-2 without setae on inferior margin; P-3 with stout setae on inferior margin and superior-distal angle, molariform seta near inferior-distal angle. Merus with two or three molariform setae on inferior margin and clusters 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 three connate spines on inferior margin. Propodus with complex setae and connate spines on inferior margin as figured; P-1 with two complex setae and four or five connate spines; P-2 with two complex setae and two connate spines, P-3 with two complex setae and no connate spines.

Pereopods 4–7. Basis with slender and biplumose setae at inferior-distal angle. Ischium with three or four clusters of stout setae on inferior margin; P-5 to P-7 with one or two biplumose setae at superior-distal angle. Carpus of P-5 with one biplumose seta on anterior-distal margin, P-6 with three biplumose setae on anterior-distal margin and approximately two long biplumose setae at superior-distal angle, P-7 with 10 biplumose setae on anterior-distal margin and approximately five long biplumose setae at superior-distal angle. Propodus inferior distal angle with one stout and one reduced complex seta; posterior-distal margin with one stout seta; superior-distal angle with one stout and one biplumose seta.

Pleopods. Pl-1 to Pl-4 peduncle with one biplumose and three coupling setae on medial margin. Pl-2 to Pl-5 lateral margin of peduncle with one stout seta. Pl-3 exopod with partial transverse suture, Pl-4 to Pl-5 exopod with complete transverse suture. Pl-1 to Pl-3 endopods with approximately six or seven PMS; exopods with approximately 14–19 PMS. Pl-4 endopod with approximately four PMS; exopod with approximately 21 PMS. Pl-5 endopod subovate, without setation; exopod with approximately eight PMS.

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

Description of male

As described for female except for the following. Pleon with three free pleonites. Antennae 1 peduncular article 2 with palmate setae; flagellum composed of two articles, a long proximal article with four jointed aesthetascs; distal article short with two aesthetascs, one biplumose and six slender setae. Antennae 2 peduncular articles 2–5 with slender setae, articles 4 and 5 with biplumose setae; flagellum sixarticulate, all articles with clusters of slender setae in the anterior-distal region. Coxae 4–7 concave.

Distribution

This species is widely distributed in the intertidal areas of Bermuda. So far it has been collected from Bailey Bay , Devonshire Bay, Castle Harbor in St George’s Parish, and Shelly Bay in Hamilton Parish .