Euphausia americana Hansen, 1911
Etymology: Euphausia - brightly shining; americana - American
Eye: The eye is round and medium in size (E. americana eye & rostrum). The eye diameter : carapace length is about 0.17.
Peduncle of 1st Antenna: The 1st segment has a pectinate lappet (E. americana lappet) projecting anteriorly over the 2nd segment. The lappet has 5-6 denticles along the margin. The 2nd segment, dorsal-distally, has a pair of rudimentary subacute tubercles, or none at all. The 3rd segment has a low keel (E. americana,).
Rostrum: It is long and sharply pointed, reaching almost to the anterior limit of the eyes (E. americana eye & rostrum).
Carapace: There are two pairs of lateral carapace denticles (E. americana carapace denticle). The gastric region is domed.
Abdomen: There are no dorsal spines or specific features (E. americana).
Length: Adults are 8-12 mm.
Petasma: The terminal process is short and thick, terminating in a strong 4-tyned fork. The curved proximal process is clearly expanded beyond the middle on its inner side. There are some distinct but fine saw-teeth near the tapered acute end (E. americana petasma).
Thelycum: Described by Guglielmo and Costanzo, 1978.
Comments: E. americana together with E. eximia and E. krohni have conspicuous pectinate lappets. The small species E. americana has 5-6 denticles along the margin of the lappet. The large species, E. eximia has as many as 12 denticles while E. krohni usually has 9, the outermost of which is distally trifurcate.
HORIZONTAL DISTRIBUTION
E. americana is confined to the Atlantic where its range extends northwards on the west to about 45°N and southwards down the coast of South America to about 32.5°S (E. americana distribution).
VERTICAL DISTRIBUTION
E. americana usually lives close to the surface but has been found at deeper depths.
LARVAE
Undescribed.
We expect the larvae of E. americana to be similar to the larvae of the closely related species E. eximia and E. krohni .