Ulcina olrikii

Common Name

Arctic Alligatorfish

Year Described

L├╝tken, 1877


Dorsal Fin: 5-7
Anal Fin: 5-7
Pectoral Fin: 14-15
Pelvic Fin: I, 2
Caudal Fin: 10 (principle)
Branchiostegal Rays: 5-6
Vertebrae: 37-39

Body very elongate and tapering posteriorly (deepest in pectoral region), with a flattened head. Body and head covered with armored plates. Eyes large. Several rows of small spines on the body (correspond to bony plates). Head expanded laterally and flattened, with numerous low bony ridges and spines. Snout protruding with a curved spine on each side. Mouth subterminal; reaches anterior margin of eye. A single dorsal fin (no spines). Anal fin origin directly under dorsal fin origin. Pectoral fins large. Caudal fin small and rounded.


Brown above with small dark spots or reticulations on head and body. Sometimes with several vague dark saddles. A few dark bands radiate from lower eye. Ventral half of body apruptly whitish. Fins (except for anal fin) with spot-bands of dark brown.


Maximum size to 8.6cm.


Benthic from 18-110m, over soft or hard bottoms.


Northwestern Atlantic: Arctic to Labrador, including Hudson Bay.


Froese, R. & D. Pauly. Editors. 2012. FishBase. World Wide Web electronic publication: www.fishbase.org, version (06/2012).

Fahay, M.P. 2005. Agonidae. In M.P. Fahay, Early stages of fishes in the western North Atlantic Ocean, Vol II, p. 982-986. Northwest Atlantic Fisheries Organization, Dartmouth, Nova Scotia, Canada, 1696 p.