34 



R. HUYS AND S. CONROY-DALTON 



Clytemnestra rostrata (Brady, 1883) sensu Huys et al. (1996): pp. 



300-303, Figs 120A-G, 121A-D. 

 Clytemnestra rostrata (Brady, 1883) sensu Boxshall & Huys (1998): 



p. 782, Fig. 13(a)-(b). 



Type locality. Bay of Cadiz, 36°30'N 7°20'W (Spain). 



ETYMOLOGY. The species is named in honour of Carl Claus, one of 

 the most prolific 19th century copepodologists, who first called 

 attention to the distinctiveness of the clytemnestrid genera. 



Type material. Holotype 9 dissected on 10 slides (BMNH 

 1999.1035). Paratypes are 2 dissected 66 (on 2 and 5 slides, 

 respectively), 2 dissected 9 (on 1 slide each), and 9 99(1 damaged), 

 1 6\ 4 copepodids (2 Cop V, 1 Cop IV, 1 Cop III) in alcohol (BMNH 

 1999.1036-1055). In addition, 2 99 and 1 6 were prepared for 

 SEM. Donated by J.M. Gee, collected by A. Lindley (Plymouth 

 Marine Laboratory), 1984. 



Other material examined. 4 99, 266: Adriatic Sea, Station 

 CJ-008, Pelegrin, Hvar (Croatia), leg. F. Krsinid, 'Bios', 23 May 

 1998 (BMNH 1999.1072-1077). 



Description. 



FEMALE. Total body length from tip of rostrum to posterior margin 

 of caudal rami: 979-1067 urn (x = 1017 um; n = 8). Maximum width 

 (306 um) measured at posterior margin of cephalic shield. Postero- 

 lateral angles of cephalothorax only weakly expanded laterally but 

 markedly produced posteriorly (Fig. 19A, B). Somites bearing P2- 

 P4 successively decreasing in width posteriorly and bearing 

 backwardly produced alate processes. 



Genital double-somite (Figs 23A; 27C) slightly constricted bilat- 

 erally; original segmentation marked by two minute chitinous patches 

 ventrally. Copulatory pore (Figs 23C, D; 27 A, C) located medially 

 in large circular depression, halfway the length of genital double- 

 somite; leading to anteriorly directed, strongly chitinized duct which 

 at level of P5-bearing somite enters median seminal receptacle. 

 Genital apertures located far anteriorly; closed off by small opercula 

 derived from vestigial P6; each with 1 well developed seta (Figs 

 23C; 27D). 



Urosomites with zone of small denticles around dorsal hind 

 margin (not figured in Fig. 19A, but see Fig. 23B); penultimate and 

 anal somites also with larger spinules around ventral hind margin 

 (Fig. 23A). 



Caudal rami short (Figs 23B; 26A), convergent; conical in shape 

 with stepped inner and outer margins marking insertion sites of setae 

 I, II and IV-V; produced into conical process bearing terminal pore; 

 with numerous ventral pores as illustrated in Fig. 26A. Setae I — II 

 bipinnate, spiniform and strongly developed; seta I 1.85 times as 

 long as seta II, extending beyond apex of caudal ramus. Seta III 

 minutely bipinnate. Setae IV-V basally fused, without fracture 

 planes, multipinnate and spiniform; seta V about 2.1 times ramus 

 length. Seta VI minute, bare; seta VII biarticulate at base, bare. 



Rostrum (Figs 19A; 211) triangular and well offset, completely 

 fused to cephalothorax; with numerous dorsal surface pores as fig- 

 ured, none on ventral surface; with minute lateral sensillae near apex. 



Antennule (Fig. 20A) slender, 6-segmented; segment 6 very long. 

 Plumose setae present on segments l^t. Segment 1 with small pore 

 near seta and few long setules along anterior margin. Armature 

 formula: 1-[1 plumose], 2-[6 + 1 plumose + 3 pinnate], 3-[5 + 2 

 plumose + 1 transformed], 4-[l + 1 plumose + (1 transformed + ae)], 

 5-[l], 6-[ll + acrothek]. Apical acrothek consisting of aesthetasc, 

 long transformed seta and short bare seta. Transformed setae on 

 segments 3, 4 and 6 long and aesthetasc-like, with minutely spiniform 

 tip; those on segments 4 and 6 basally fused to aesthetasc. Rudimen- 



tary element present at base of acrothek (arrowed in Fig. 20B). 



Antenna (Fig. 21 A, B) 4-segmented, comprising coxa, basis and 

 2-segmented endopod. Coxa well developed, bare. Basis and proxi- 

 mal endopod segment with few surface denticles; unarmed. Exopod 

 inserted in membranous area between basis and endopod; repres- 

 ented by small, weakly chitinized segment bearing strong recurved 

 seta apically; exopodal seta multipinnate, spinules in proximal third 

 distinctly longer. Distal endopod segment with 3 surface frills and 

 minute denticles on outer surface and patch of long setules on medial 

 surface; lateral armature consisting of 1 pinnate seta; distal armature 

 consisting of 1 subapical and 3 apical, non-geniculate, bipinnate or 

 multipinnate elements, 2 of which spiniform, recurved and bearing 

 long spinules proximally; distal margin with 2 rudimentary elements 

 on inner surface (arrowed in Fig. 2 IB). 



Labrum (Fig. 21H) large, with 6 secretory pores on anterior 

 surface; distal margin smooth medially and with spinular patch on 

 either lateral lobe. 



Mandible (Fig. 21C-E) reduced. Palp represented by single na- 

 ked seta. Gnathobase long and narrow, stylet-like; produced into 

 number of cuspidate processes apically and subapically; without 

 dorsal seta(e). 



Paragnaths (Fig. 21H) well developed lobes without any con- 

 spicuous ornamentation. 



Maxillule (Fig. 2 IF) reduced; represented by small triangular 

 segment bearing naked apical seta and raised pore along outer 

 margin. 



Maxilla (Fig. 2 1 G, H) 2-segmented, comprising elongate syncoxa 

 and allobasis. Syncoxa with expanded basal portion; exit of maxil- 

 lary gland large (arrowed in Fig. 21G), partly concealed under 

 lobate extension; coxal endite cylindrical, with 2 naked setae apically. 

 Allobasis with large articulating claw distally, smaller inner spine 

 and unipinnate seta along outer margin. 



Maxilliped (Fig. 22A) very large, articulating with well devel- 

 oped pedestal; 3-segmented, comprising syncoxa, basis and endopod. 

 Syncoxa extremely elongate, longer than basis; without ornamenta- 

 tion but with 1 anterior, plumose seta near membranous articulation 

 with basis. Basis elongate; distal third of palmar margin with double 

 spinule row and 2 elements located closely to articulation with 

 endopod (Fig. 22B-D); proximal element spiniform and bare, distal 

 element stubby and spinulose. Endopod represented by short seg- 

 ment bearing naked claw; accessory armature consisting of 3 anterior 

 setae and 2 posterior setae (Fig. 22B-D). 



Swimming legs with wide, narrow intercoxal sclerites and well 

 developed praecoxa; both without ornamentation. Rami 3-segmented 

 except for PI exopod. 



PI (Fig. 23E) separated from maxillipeds by large membranous 

 area. Coxa and basis prolonged along dorsoventral axis; without 

 surface ornamentation. Basis without inner or outer seta (spine). 

 Exopod 1 -segmented, represented by elongate segment bearing long 

 setules along outer margin; with subapical pore and 3 setiform 

 elements distally, outer one less than half the length of others. 

 Endopod 3-segmented; segments decreasing in size distally, each 

 with anterior pore and few spinules/setules along outer margin; enp- 

 1 with very long inner seta; ornamentation of inner elements typically 

 (multi)pinnate, distal elements plumose. 



P2-P4 (Figs 24A, B; 25B) with transversely prolonged basis 

 bearing short outer seta. Endopods distinctly longer than exopods. 

 Exopodal outer spines setiform with distinct flagellate tip. Exopod 

 segments typically with pore near outer distal corner; without 

 ornamentation. Endopods with long proximal segment, particularly 

 in P2-P3; segments with anterior pore, setules along outer margin 

 and spinules (enp-2 and -3) or setular tuft (enp-1) on posterior 

 surface; setal ornamentation typically combination of setular and 



