Calanoidea: Families

J.M. Bradford-Grieve


Tortanidae Sars, 1902

Description. Female. Rostrum without filaments; rostral margin not extended. Cephalosome and pedigerous somite 1 separate; pedigerous somites 4 and 5 separate. Posterior corners of prosome in lateral view bluntly rounded, or with 1 acute point, or triangular or obtusely pointed; dorsal view symmetrical. Urosome with 2 free somites, or with 3 free somites. Genital double-somite symmetrical in dorsal view, or asymmetrical in dorsal view; gonopores close together and totally covered by single genital operculum; without seminal receptacles. Caudal rami symmetrical, or asymmetrical.

Mouthparts. Antenna 1 with 12-15 free segments; ancestral segments X and XI separate. Antenna 2 exopod with 3 free segments; 5 setae; with 1 terminal seta, or with 2 terminal setae; basis and endopod fused, or separate. Mandible basis without setae; endopod terminal segment with 6 setae. Maxilla 1 basal exite seta absent; exopod absent. Maxilla 2 coxal epipodite seta absent; endopod setae claw-like. Maxilliped with coxa large, but basis and endopod reduced; coxal endite 2 with 1 seta.

Legs. Leg 1 basis inner distal seta absent; outer seta absent; endopod with 2 segments; exopod with 3 segments; exopod segment 1 without outer distal spine; exopod segment 3 with 4 inner setae. Leg 2 endopod with 2 segments; exopod with 3 segments; exopod segment 3 with 2 outer spines. Leg 3 basis outer distal spine absent. Legs 3 and 4 endopod with 2 segments; exopod with 3 segments; exopod segment 3 with 3 outer spines; exopod segment 3 with 5 inner setae. Legs 2-4 surfaces naked; terminal spine with outer border serrated. Leg 5 present; very dissimilar from legs 2-4; coxa inner border without seta; uniramous, may be slightly asymmetrical, coxae and intercoxal sclerite fused with outer seta, exopod 1-segmented, variously shaped: may be elongate and tapering with or without terminal accessory teeth, through to rectangular with lateral and terminal spines and inner distal tooth.

Mode of life. Pelagic, in coastal waters.

Depth distribution. Epipelagic (0-500 m).

Generic composition. This family contains only the genus Tortanus Giesbrecht, 1888.


(Variant) Male (sexually dimorphic characters).

Description. Male. 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. Urosome symmetrical in dorsal view, or asymmetrical in dorsal view.

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

Legs. Right leg 5 uniramous; exopod 2-segmented, segment 1 often expanded into inner lamellate process armed with up to 3 setae, segment 2 curved, armed with 3 or 4 small setae and forming a subchela with the process on segment 1. Left leg 5 uniramous; exopod 2-segmented, segment 1 elongate with inner and outer seta, segment 2 curved, typically armed with 2 setae on inner margin, an apical seta and 2 on the outer margin.



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