Calanoidea: Families

J.M. Bradford-Grieve


Discoidae Gordejeva, 1975

Description. Female. Anterior head in dorsal view rounded or bluntly triangular. Rostrum without filaments; rostral margin extends into 2 points, or extends into 1 blunt protrusion, or not extended. Cephalosome and pedigerous somite 1 fused or partly fused, or separate; pedigerous somites 4 and 5 fused or partly fused, or separate. Posterior corners of prosome in lateral view bluntly rounded, or triangular or obtusely pointed; dorsal view symmetrical. Genital double-somite symmetrical in dorsal view; gonopores close together and totally covered by single genital operculum. Caudal rami symmetrical; seta VII located dorsally or laterally, or absent.

Mouthparts. Antenna 1 with 17-25 free segments; ancestral segments X and XI separate. Antenna 2 exopod with 8 free segments; 4-11 setae; with 3 terminal setae, or with 4 terminal setae; basis and endopod separate. Mandible basis without setae; endopod terminal segment with 6 setae, or 8 setae. Maxilla 1 basal exite seta present, or absent; exopod extends short of endopod distal border. Maxilla 2 coxal epipodite seta absent. Maxilliped coxal endite 2 without setae, or with 1 seta, or with 2 setae, or with 3 setae.

Legs. Leg 1 basis inner distal seta absent; outer seta absent; endopod with 1 segment, or with 2 segments, or with 3 segments; exopod with 3 segments; exopod segment 1 with outer distal spine; exopod segment 3 with 4 inner setae. Leg 2 endopod with 1 segment, or with 3 segments; exopod with 3 segments; exopod segment 3 with 2 outer spines, or with 3 outer spines. Leg 3 basis outer distal spine absent; endopod segment 3 with 3-5 setae. Legs 3 and 4 endopod with 1 segment, or with 3 segments; exopod with 3 segments; exopod segment 3 with 2 outer spines, or 3 outer spines; exopod segment 3 with 5 inner setae. Leg 4 endopod segment 3 with 3-5 setae. Legs 2-4 surfaces naked; terminal spine with outer border serrated. Leg 5 absent, or rudimentary; very dissimilar from legs 2-4; coxa inner border without seta.

Mode of life. Pelagic, in oceanic waters.

Depth distribution. Mesopelagic (500-1000 m), or bathypelagic (greater than 1000 m).

Generic composition. This family contains 3 genera: Disco Grice & Hulsemann, 1965; Paradisco Gordeyeva, 1975; Prodisco Gordeyeva, 1975.


(Variant) Male (sexually dimorphic characters).

Description. Male. Pedigerous somites 4 and 5 fused or partly fused. Posterior corners of prosome in lateral view bluntly rounded.

Mouthparts. Mouthparts well-developed. Antenna 1 geniculate on left. Maxilliped endopod segments 5 and 6 with outer setae normal.

Legs. Leg 2 endopod with 3 segments. Legs 3 and 4 endopod with 3 segments. Right leg 5 uniramous, or biramous; endopod separate from basis and 1-segmented, or 2-segmented, or 3-segmented; exopod elongate, 3-segmented, segments 1 and 2 naked or with small outer distal spine, segment 3 with 1-3 terminal spines. Left leg 5 uniramous, or biramous; endopod 1-segmented, or 2-segmented, or 3-segmented; exopod elongate, 3-segmented, segments 1 and 2 naked or with small outer distal spine, segment 2 may be extended into inner process, segment 3 with 1-2 terminal spines.



Cite this publication as: 'Bradford-Grieve, J.M. (2002 onwards). Calanoida: families. Version 1: 2 October 2002. http://crustacea.net'.