Vyshkvartzeva, 1994
Short Description:
Senecella siberica is an aetideid calanoid copepod known after both sexes (female 3.0-3.3 mm and male 2.8-2.88 mm) from the Kara and Laptev Sea and their bays and estuaries.
Taxonomic Description:
Female. (Description after Vyshkvartzeva (1994) with modifications). Total length 3.0-3.3 mm. Cephalothorax about 2.9-3.0 times longer than abdomen. Rostrum absent. Th5 posterior corners rounded, reaching the anterior third of genital segment's length. Genital segment is nearly as long as 3 following segments together, slightly asymmetrical (ventral view). A1 24-jointed. Ri A2 slightly shorter than Re. Re1 and Re2 A2 with 2 setae each. Md palp base with 2 setae; Ri1 with 2 setae; Ri2 with 10 setae. Mx1 gnathobase with 9 terminal spines and 4 posterior setae; second and third internal lobes with 5 and 4 setae respectively; protopodite near Ri base with 5 setae; Ri with 16 setae; Re with 10 setae. Mx2 with 6 endites; sixth endite with 2 setae. Mxp protopodite with 1 seta proximally and groups of 2, 3 and 3 setae (from proximal to distal part of the joint). Segmentation of P1-P4 typical of Aetideidae. Re1 P1 without external spine; Re2-Re3 P1 with external spine each. Re3 P2-P4 with 3 external spines each.
Male. Total length 2.8-2.88 mm. Cephalothorax nearly 2.5-2.6 times longer than abdomen. Rostrum present, very small, conical. A1 24-jointed, symmetrical, reaching the end of cephalothorax. A2 similar to female, but the setae of Re1-Re2 are shorter. Md palp base with 1 rudimentary seta; Ri1 Md without seta; Ri2 with 8 setae. Md gnathobase, Mx1 and Mx2 are severely reduced. P1-P4 almost like in females, but external spines of Re2 P1 and of the 1st and 2nd spines of Re3 P2-P4 are shorter. P5 is large and asymmetrical. Right Ri P5 long clapper-like, reaching slightly beyond of right Re2; Re1 subcylindrical, 2 times as long as wide; a narrow hyaline lamella rises at the inner distal angle of this segment and extends inwards along Re2; Re2 is small, with small spine at its outer distal angle and long terminal hook, not separated from the joint. Left Ri is about trapezoidal with a narrow base and cup-like wide distal edge and with digitiform process at the outer distal angle, reaching far beyond Re1. Re1 left is oblong, 1.5 times as long as wide with convex outer edge; Re2 is larger than Rel, distal border hyaline, wavy with small spine in the inner distal angle and digitiform process near its base.
Geographical distribution:
The Kara and Laptev Sea and their bays and estuaries (Vyshkvartzeva, 1994).
Type locality: Neelov Bay (71°46'N 128°51'E).
Ecology:
The species was found in waters with salinities from 1 to 22ä and T° from -0.48 to + 8°C; possibly may inhabit freshwater bodies of North Siberia. The species seems to reproduce in winter (Vyshkvartzeva, 1994).