Morphological differentiation between species of Pseudocalanus is very ambiguous, identification bordering impossible in juvenile stages. Adult P. elongatus can be distinguished from other species of the genus by the anteriorly tapered cephalosome.
Temperate and sub-Arctic North Atlantic Ocean. Range extends south of the English channel to the Alboran Sea in the Mediterranean.
Oceanic, epi-bathypelagic
As differences between species are very subtle, for general morphological description, see genus diagnosis.
Female:
Cephalothorax stocky in lateral view, cephalosome strongly tapered anteriorly, barely protruding anteriad of the rostrum. Posteroventral margins of the first 2 thoracic segments without or with very short spiniform processes. Posteroventral margin of the 3rd thoracic segment is convex and smoothly rounded. The mediodorsal surface of one or more abdominal segments 1-3 with a short sensillum and integumental pore. Seminal receptacle small. The ratio of the lengths of the 1st and 2nd basipodites of P4 is less than 1.5.
Egg diameter average 125 um.
Female: 0,91-1,77 mm
Male: 0,91-1,37 mm
Pseudocalanus elongatus is a copepod found primarily in the Atlantic Ocean.
The female P. elongatus ranges from about .7 to 1.8 millimetres (0.028 to 0.071 in) in length, and the male is usually between about .5 and 1.4 millimetres (0.020 and 0.055 in).[1]
P. elongatus is generally found in temperate or sub-Arctic waters in the Atlantic[2] and in the western Mediterranean Sea,[3] although it is also found in the Arctic, and off of the southwestern coast of the United States.[1]
P. elongatus is abundant (at least off the coast of Plymouth, UK) from March to October, and breeds from January to December,[4] usually having from four to six generations.[3] It is most abundant from April to August,[4] and peaks during June and August. In the southern North Sea, P. elongatus breeds year round. The peaks in abundance here in June, August, and October is likely caused by advection of other individuals into the area. In this region, maximum reproduction occurs during April and May (during which the concentration of chlorophyll a is at its highest), clutch size and egg production rate being highest during this period. Clutch size, hatching success, and egg production rate are negatively correlated with temperature. The proportion of breeding females is significantly related to the concentration of chlorophyll a.[3]
Pseudocalanus elongatus is a copepod found primarily in the Atlantic Ocean.
