Calanoidea: Families

J.M. Bradford-Grieve

Scolecitrichidae Giesbrecht, 1892

Description. Female. Anterior head in dorsal view crested, or rounded or bluntly triangular. Rostrum with 2 filaments, or without filaments; rostral margin extends into 2 points, or extends into 1 blunt protrusion, or extends into 2 blunt protrusions, 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 with 1 acute point, 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; with pair of seminal receptacles; with pair of copulatory pores that are completely covered by genital operculum. Caudal rami symmetrical; seta VII located ventrally.

Mouthparts. Antenna 1 with 19-24 free segments; ancestral segments X and XI fused. Antenna 2 exopod with 6-7 free segments; 7-8 setae; basis and endopod separate. Mandible basis with 1 seta, or with 2 setae, or with 3 setae; endopod terminal segment with 7-9 setae. Maxilla 1 basal exite seta absent; exopod extends short of endopod distal border. Maxilla 2 coxal epipodite seta absent; endopod setae of sensory type; endopod with 3 worm-like setae; endopod with 5 brush-like setae. Maxilliped coxal endite 2 with 1 seta.

Legs. Leg 1 basis inner distal seta inserted directly on surface of joint, or absent; 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 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 3 outer spines; exopod segment 3 with 4 inner setae. Leg 4 endopod segment 3 with 5 setae. Legs 2-4 surfaces strongly spinulose, or weakly spinulose; terminal spine with outer border serrated. Leg 5 present, or absent; very dissimilar from legs 2-4; coxa inner border without seta; if present, coxae and intercoxal sclerite fused, basis and exopod segment 1 fused, partly fused, or separate, exopod 1-segmented, variously ornamented with terminal, inner border, and sometimes outer border articulated spines and sometimes outer border teeth.

Mode of life. Pelagic, in oceanic waters.

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

Generic composition. This following 24 genera have been assigned by different workers to this family: Amallothrix Sars, 1925; Archescolecithrix Vyshkvartzeva, 1989; Falsilandrumius Vyshkvartzeva, 2001; Grievella Ferrari & Markhaseva, 2000; Heteramalla Sars, 1907; Landrumius Park, 1983; Lophothrix Giesbrecht, 1895; Macandrewella Scott, 1909; Mixtocalanus Brodsky, 1950; Neoscolecithrix Canu, 1896; Parascaphocalanus Brodsky, 1955; Pseudamallothrix Vyshkvartzeva, 2000; Pseudophaenna Sars, 1902; Puchinia Vyshkvartzeva, 1989; Racovitzanus Giesbrecht, 1902; Scaphocalanus Sars, 1900; Scolecithricella Sars, 1902; Scolecitrichopsis Vyshkvartzeva, 2000; Scolecithrix Brady, 1883; Scolecocalanus Farran, 1936; Scopalatum Roe, 1975; Scottocalanus Sars, 1905; Undinothrix Tanaka, 1961. Xantharus Andronov, 1981. A number of these genera are not of the typical scolecitrichid form (e.g. Falsilandrumius, Grievella, Landrumius, Puchinia, Neoscolecithrix, Xantharus) and key out as Tharybidae in this key. There is a need for further review of a number of genera and families in the Clausocalanoidea.

(Variant) Male (sexually dimorphic characters).

Description. Male.

Mouthparts. Mouthparts well-developed, or reduced (especially maxillae 1 and 2). Antenna 1 similar, neither geniculate. Maxilliped coxal endite 2 without setae, or with 1 seta; endopod segments 5 and 6 with outer setae enlarged, or normal.

Legs. Right leg 5 uniramous, or biramous; endopod separate from basis and 1-segmented, or 2-segmented; exopod 2-3 segmented, proximal segment may have processes, terminal segment may be variously modified. Left leg 5 uniramous, or biramous; endopod 1-segmented, or 2-segmented, or 3-segmented; exopod 3-segmented, longer or shorter than endopod.

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