Scientific Name and Authority

Iais californica   (Richardson, 1904)


Iais californica is a small isopod, living commensally on the pleopods of the isopod Sphaeroma quoianum, a wood-borer in marine and estuarine habitats. Iais californica has an elongated egg-shaped body, which is broadest in pereaonal segment 7 and tapered towards the head. Coxal plates are visible in dorsal view. The pleotelson is shield-shaped, with long biramous uropods protruding beyond it. The head is roughly oval, with medium-sized eyes. Antenna 1 is 1/6 the size of the body length and composed of 6 segments, while Antenna 2 is 6/10 of the body length, with a flagellum of 24 segments. In males, Pleopods 1 and 2 are modified for copulation. Pleopods 1 are fused to form a narrow appendage (the sympod), not widening near the tip and ending in a pair of rounded processes, each bearing 5 setae (Menzies and Barnard 1951, California). Pleopods 2 are not fused, but the inner ramus is modified into a needle-like stylus. The pleotelson is wider than it is long and the uropods are about half as long as the pleotelson. One male was 2.7 mm long (Menzies and Barnard 1951), and Schultz (1969) gives an average length of 1.9 mm. Description based on: Hurley 1956, Menzies and Barnard 1951, Schultz 1969, and Wilson and Wagele 1994.

Iais pubescens (s. l.) was described by Dana from Tierra del Fuego. Chilton reported this species from New Zealand in 1893, as I. pubescens var. longistylis, associated with S. quoianum, but it was later found to be identical with I. californica (Menzies and Barnard 1951; Hurley 1956).

Taxonomic Classification:

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Subclass: Eumalacostraca
Superorder: Peracarida
Order: Isopoda
Suborder: Asellota
Family: Janiridae
Genus: Iais
Species: californica


Iais pubescens var. longistylis (Chilton, 1912)

Ianiropsis californica (Richardson, 1904)