''Hallaxa chani'' is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
sea slug
Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary time ...
or dorid
nudibranch
Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, ...
, a
marine gastropod mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Actinocyclidae
Actinocyclidae is a family of sea slugs, dorid nudibranchs, marine gastropod mollusks in the superfamily Doridoidea. This family is within the clade Euctenidiacea.
Taxonomy
Genera within the family Actinocyclidae include:
* ''Actinocyclus'' E ...
.
[Turgeon, D.; Quinn, J.F.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.; Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. (1998). Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. American Fisheries Society Special Publication, 26. American Fisheries Society: Bethesda, MD (USA). . IX, 526 + cd-rom pp. (look up in IMIS) page(s): 127 Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=581807 on 2012-02-26][Rosenberg, G. (2015). Hallaxa chani Gosliner & Williams, 1975. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=581807 on 2016-05-21]
Distribution
''Hallaxa chani'' ranges from central California to southeast Alaska (Gosliner & Williams, 1975; Millen, 1989).
It is rare in the southern part of its range, but in the Pacific Northwest, can be quite common in boulder/cobble habitats with large populations of its sponge prey, ''Halisarca'' sp. (Goddard, 1981, 1984; Goddard et al., 1997). Most records of ''Hallaxa chani'' are from the intertidal zone, but Millen (1983 and 1989) found it subtidally at unspecified depths in
British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
and
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
.
Description
''Hallaxa chani'' preys exclusively on ''Halisarca'' sp., a slick-textured dendroceratid sponge lacking both spicules and spongin fibers (Goddard, 1981, 1984, 1998). Like its congeners, ''Hallaxa chani'' is remarkably cryptic on its prey, both in color and texture. Both are tan to yellow-tan in color, and ''Hallaxa chani'' also lacks spicules. Additionally, the mantle edge of''Hallaxa chani'' is semi-translucent and blends in almost seamlessly when spread out on the surface of ''Halisarca'' sp.
The radular teeth of ''Hallaxa chani'' are similar in shape to those of other nudibranchs known to prey primarily on sponges that lack spicules and provided an early clue that ''Hallaxa chani'' does not feed on colonial ascidians as originally reported by McDonald & Nybakken (1978) (Goddard, 1981). As noted by Nybakken & McDonald (1981), nudibranchs that specialize on ascidians or fleshy ctenostome bryozoans have a radula dominated by large, paired, wing-shaped lateral teeth. Dorids specializing on dendroceratid and dictyoceratid sponges have thin, comb-like outer lateral teeth with multiple denticles (Goddard, 1981, personal observations; Rudman, 1984; and see electron micrographs of radulae in Gosliner & Johnson, 1994).
References
* Gosliner T.M. & Johnson S. (1994) ''Review of the genus Hallaxa (Nudibranchia: Actinocyclidae) with descriptions of nine new species''. The Veliger 37(2): 155-191.
Actinocyclidae
Gastropods described in 1975
{{Heterobranchia-stub