Farran, 1936a
Short Description:
Jaschnovia brevis is an aetideid calanoid copepod known after both sexes (female 2.31-2.45 mm and male 1.85-2.30 mm in length) from the north-western Atlantic, the Greenland Sea, the central part of the Arctic Ocean, the region of Novosibirsk Islands. Very probably benthopelagic species.
Taxonomic Description:
Female. Total length 2.31-2.45 mm. Cephalothorax 3.1-3.5 times longer than abdomen. Th5 posterior corners rounded. A1 nearly equal to cephalothorax in length, or reaching Th3. Oral parts and P1-P4 typical of the genus.
Male. Total length 1.85-2.30 mm. Th5 posterior corners rounded and not curved externally (dorsal view). Cephalothorax 2.8 times longer than abdomen. A1 reaching the middle of genital segment. P1-P4 as in females, only P4 surface setation weaker. P5 typical of the genus.
Remarks: Bradyetes brevis Farran, 1936 was removed from Bradyetes to Jaschnovia , and Jaschnovia johnsoni Markhaseva, 1980 was considered to be its junior synonym. The most important distinguishing features from Bradyetes are: absence of sensitive appendage in proximal part of Mxp protopodite, Re1 P1 lacking external spine, and also not so important features (Markhaseva, 1996).
Vertical distribution:
The ecology of the species is obscure: It was found in total hauls from 50 m when net contacted with bottom (Farran, 1936a), and in near bottom hauls from depths of 17 m (Markhaseva, 1980a), that might be considered as evidence of possible relation the life cycle to sea bed, on the other hand the species was found in under ice hauls (surface) in the central part of Arctic Basin (Markhaseva, 1980a).
Geographical distribution:
The north-western part of the Atlantic Ocean: region of 37°N (Wheeler, 1970), the Greenland Sea (Farran, 1936a), the central part of Arctic Basin (Johnson, 1963; Markhaseva, 1996), the region of Novosibirsk Islands, (Markhaseva, 1980a).
Type locality: 72°55'N 25°W.
Material examined:
24 female and 3 males from samples 564-566, 568. See examined samples module.