Henricia leviuscula (Stimpson, 1857)
Common name(s): Blood star, Pacific blood star
|Synonyms: Linckia leviuscula|
|Henricia leviuscula, collected from 100-150 m depth in San Juan Channel|
|(Photo by: Dave Cowles, July 2005)|
How to Distinguish from Similar Species: This species is variable and is likely a species complex. H. sanguinolenta has no prominent marginal plates and the rays are thickened at the base, forming creases between them. Henricia pumila is a small species with genital pores slightly oral to the margin of the disk and is a mottled color.
In 2010 Douglas Eernisse, M. Strathmann, E.Corstorphine, R. Clark, and C. Mah were working on a key to distinguish species in this complex.
Geographical Range: Aleutian Islands, AK to Baja California, Mexico; Japan
Depth Range: Low intertidal to 671 m
Habitat: Common in the rocky intertidal and subtidally in rocky and shelly hash areas.
Biology/Natural History: Feeds mainly on sponges, or on particulates which stick to mucus on the body surface and are passed to the mouth. Often has a commensal scaleworm, Arctonoe vittata. Small females may brood their young in winter (or the brooders may be a separate species--this is most likely the correct interpretation). Has ocelli at the tips of the rays.
Henricia leviuscula is fairly stiff with only small papulae and
tube feet. It seems to rely much more on seawater uptake through
the madreporite than does Leptasterias
hexactis, another intertidal species of similar size (Ferguson,
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Brusca and Brusca, 1978
McConnaughey and McConnaughey, 1985
O'Clair and O'Clair, 1998
Ricketts et al., 1993
Ferguson, John C., 1994. Madreporite inflow of seawater to maintain body fluids in five species of starfish. pp. 285-289 in Bruno David, Alain Guille, Jean-Pierre Feral, and Michel Roux (eds). Echinoderms through time. Balkema, Rotterdam.
McEdward, Larry R. and Benjamin G. Miner, 2006. Estimation and interpretation of egg provisioning in marine invertebrates. Integrative and Comparative Biology 46:3 pp 224-232
This species is found in many sizes and colors, and may be a species complex. Photo by Dave Cowles, July 2005
A closeup view of the aboral ossicles. This photo was taken on the 4-rayed seastar below.
Compare the pattern of these aboral ossicles to that in Henricia pumila.
This closeup of the aboral portion of a ray in another individual shows that the aboral ossicles have about 30-60 closely-spaced spinelets. Photo by Dave Cowles, August 2015
This view of the oral side of a ray shows that the adambulacral ossicles each have two rows of 5-12 stubby spinelets arranged transversely to the ambulacral groove.
This large individual, with ray length from 11.5 to 12.5 cm, has only 4 rays and not a hint of another ray regenerating. It is much larger than most intertidal H. leviuscula.
This individual, found on Sares Head in 2012, had 6 rays. Ray length 7 cm.
The madreporite of the 4-rayed individual above is orange and not strongly distinguished from the ossicles around it.
The ossicles along the margin of the ambulacral grooves are larger, usually lighter, and form 3 rows.
The ambulacral groove is narrow. Here the enlarged marginal ossicles can also be seen. Photo by Dave Cowles, July 2005
A beige form is especially common in deep water. This is probably actually H. sanguinolenta. Collected at 100-150 m in San Juan Channel. Photo by Dave Cowles, July 2005
A saddle-like marking of lilac blotches between the rays is a common color variant. This may also be a separate species from H. leviuscula. Collected at 100-150 m depth,San Juan Channel. Photo by Dave Cowles, July 2005
This closeup of the madreporite of a saddled or blotched individual shows that the madreporite looks different than in the orange individuals.
This individual, photographed underwater by Kirt Onthank near Northwest island in February 2006, has even more pronounced lilac patches over the base of the rays and the central disk.
The nudibranch is Cadlina luteomarginata.
In summer 2005 three students, Shannon Greenlaw, Jill Interlichia, and
Lyndi Hetterle did a student research project titled "Nocturnal vs diurnal
levels of activity in Henricia leviuscula. They placed 15
blood stars in an outdoor tank and placed a video time-lapse camera overhead
to record their movement. They found that the seastars moved significantly
more during the day than at night. They were not able to determine
whether this was a natural level of movement or whether the seastars were
searching for shelter from the sunlight, though a number of stars continued
substantial levels of movement even after entering the shade. The
figure below of mean distance moved as a function of time of day summarizes
their data. Daylight hours are from approximately 6:00 to 21:30.