Protohyale sp.

Common name(s): Sea flea

Synonyms: Hyale frequens, Hyale rubra frequens Protohyale sp
Phylum Arthropoda 
Subphylum Crustacea 
Class Malacostraca 
Subclass Eumalacostraca 
Superorder Peracarida 
Superfamily Talitroidea 
Family Hyalidae 
Protohyale sp. about 1 cm long, found intertidally near Rosario.
(Photo by:  Dave Cowles, July 2009)
Description:   Head to telson:
Antenna 1 is longer than the peduncle of antenna 2 but it is distinctly shorter than the entire antenna 2.
Antenna 2 has a long flagellum ( >20 articles in adults).
 The eyes are not borne on lateral lobes.

Coxa 1 is not much reduced and coxa 4 is not greatly enlarged--the coxae are of similar size range though they become gradually larger posteriorly.  The proximal posterior margin of coxa 4 has a deep concavity.

Pleon: Pleosome/Urosome:
The urosome is laterally compressed.
Uropod 1 has an enlarged peduncular spine at the base of and lateral to the rami.
Uropod 3 has a stout peduncle which does not greatly exceed the length of the telson.  The third uropod has a single, distinct main ramus, which is conical or bladelike (not flattened and paddlelike) and at least 1/2 as long as the peduncle.  This ramus has only one section.  Uropod 3 has stiff spines.  There is no second ramus on uropod 3.
The telson is naked (no spines or setae) and cleft to its base.  The apical margins are smooth.

Note:  This is a species complex.  What originally keyed to Hyale frequens in Kozloff (1987, 1996) has subsequently been subdivided into a whole group of species, some of which are found in our area and some are not.  See Bousfield and Hendrycks, 2002 for a more detailed breakdown of the species.  The species group now includes Protohyale frequens (not in our area), P. lamberti, jarretteae, P. seticornis, P. oclairi, and P. hiwatarii.

How to Distinguish from Similar Species:  Several other hyalid species have a short 2nd antennal flagellum with <20 segments and the telson has slender spinules.  Also see the note above.

Geographical Range:

Depth Range:  Intertidal to 6 m

Habitat:  A common amphipod in the rocky intertidal, in tidepools, and in kelp holdfasts,

Biology/Natural History:   Predators include the tidepool sculpin Oligocottus maculosus and the fluffy sculpin Oligocottus snyderi.



Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996 (as Hyale frequens)

General References:

Scientific Articles:
Bousfield, E.L. and E.A. Hendrycks, 2002.  The talitroidean amphipod family Hyalidae revised, with emphasis on the North Pacific fauna: systematics and distributional ecology. Amphipacifica 3(3):17-134
Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

Authors and Editors of Page:
Dave Cowles (2009):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)