Amphipoda of the Atlantic and Arctic Coasts of North America: Anonyx (Lysianassidae)

• Published in: Journal of the Fisheries Research Board of Canada
• Main Authors: Steele, Donald H., Brunel, Pierre
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1968
• Subjects: Arctic
• Online Access: http://dx.doi.org/10.1139/f68-087; http://www.nrcresearchpress.com/doi/pdf/10.1139/f68-087

In place of the widely ranging, abundant, and variable species Anonyx nugax, previously recorded from Canadian Atlantic and Arctic waters, eight less variable species of this genus are here recognized, one of which (sarsi) is new to science. Detailed descriptions, figures, distribution maps and a key applying to all sizes are given. The study of the species is based on examination of available type-specimens and the use of new characters. The systematics of the genus is discussed in a chronological review of all the relevant literature, and the status of several species is revised.Since the young of large and small species are similar among themselves, and have sometimes been wrongly described as distinct species, they are also described and illustrated at two sizes. Mature males are distinguished by elongated second antennae equipped with calceoli, in most species by the armature of the second and third uropods, and sometimes by their enlarged eyes.Three species are characterized by a row of spines accompanying single setae on the hind margin of segment 6 of peraeopods 3–4, and by a rather unprominent upper lip. One may distinguish them as follows. The large (> 33 mm) A. laticoxae has short spines on peraeopods 3–4, an anteriorly well-expanded first coxa, and an unconstricted short-spined inner ramus of uropod 2. Anonyx compactus is smaller (12–17 mm), has one elongated ventral spine on each of the first two flagellar segments of antenna 1, a posterior projection marked off by an angle from the lateral plate of metasome segment 3, a strongly parachelate peraeopod 1 with a perpendicular palm, and a fairly strongly subchelate peraeopod 2. Anonyx sarsi is of medium size (20–31 mm), has a very low and unprominent upper lip and, on the outer ramus of uropod 2, small similar-sized spines on the proximal two-thirds of the inner margin (no such spines in laticoxae and compactus); the female has tufts instead of a row of setae on the dorsal margin of the fourth peduncular segment of antenna 2, but otherwise the ...