Calanoidea: Families

J.M. Bradford-Grieve


Clausocalanidae Giesbrecht, 1892

Description. Female. Anterior head in dorsal view rounded or bluntly triangular. Rostrum with 2 filaments, or 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; dorsal view symmetrical. Genital double-somite symmetrical in dorsal view; gonopores close together and totally covered by single genital operculum; with pair of seminal receptacles; with pair of copulatory pores that are completely covered by genital operculum. Caudal rami symmetrical; seta VII located dorsally or laterally.

Mouthparts. Antenna 1 with 22-24 free segments; ancestral segments X and XI fused. Antenna 2 exopod with 6-7 free segments; 8-12 setae; basis and endopod separate. Mandible basis with 3 setae, or with 4 setae; endopod terminal segment with 9-10 setae. Maxilla 1 basal exite seta absent; exopod extends short of endopod distal border. Maxilla 2 coxal epipodite seta absent; endopod setae normal. Maxilliped coxal endite 2 without setae, or with 3 setae, or with 4 setae.

Legs. Leg 1 basis outer seta absent; endopod with 1 segment; exopod with 3 segments; exopod segment 1 with outer distal spine, or without outer distal spine; exopod segment 3 with 3 inner setae. Leg 2 endopod with 2 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 5 setae. Legs 3 and 4 endopod with 3 segments; exopod with 3 segments; exopod segment 3 with 2 outer spines, or 3 outer spines; exopod segment 3 with 4 inner setae. Leg 4 endopod segment 3 with 5 setae. Legs 2-4 surfaces weakly spinulose, or naked; terminal spine with outer border serrated. Leg 5 present, or absent, or rudimentary; very dissimilar from legs 2-4; coxa inner border without seta; if present, uniramous, coxae and intercoxal sclerite fused, basis naked, exopod 1-segmented with 2-3 terminal teeth or one seta or in form of long curved spine.

Mode of life. Pelagic, in oceanic waters or in coastal waters.

Depth distribution. Epipelagic (0-500 m), or mesopelagic (500-1000 m).

Generic composition. This family contains at least six genera: Clausocalanus Giesbrecht, 1888; Ctenocalanus Giesbrecht, 1888; Drepanopus Brady, 1883; Farrania Sars, 1920; Microcalanus Sars, 1920; Pseudocalanus Boeck, 1873. Spicipes Grice & Hulsemann, 1965 has been excluded from this family in this key. There is a need for a review of the unity of this family.


(Variant) Male (sexually dimorphic characters).

Description. Male. Rostral margin extends into 1 blunt protrusion, or not extended. Cephalosome and pedigerous somite 1 fused or partly fused; pedigerous somites 4 and 5 fused or partly fused.

Mouthparts. Mouthparts reduced (especially maxillae 1 and 2). Antenna 1 similar, neither geniculate. Maxilliped endopod segments 5 and 6 with outer setae normal.

Legs. Leg 2 exopod segment 3 with 3 outer spines. Legs 3 and 4 exopod segment 3 with 3 outer spines. Right leg 5 uniramous, or biramous; endopod separate from basis and 1-segmented; exopod 1-3 segmented, much shorter, subequal to or longer than left exopod, may end in long claw or elongate spine. Left leg 5 uniramous, or biramous; endopod 1-segmented; exopod 3-segmented, much longer, subequal to or shorter than right exopod, usually terminates in at least 1 small spinule.



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