Henricia leviuscula (Stimpson, 1857)  Common name(s): Blood star, Pacific blood star
Synonyms:  Linckia leviuscula
Phylum Echinodermata  Class Asteroidea   Order Spinulosida    Suborder Leptognathina     Family Echinasteridae
	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, 1994). 

The genus Henricia is closely related to the genus Echinaster (Medeiros-Lopes et al., 2016)

References:

General References:
  Brusca and Brusca, 1978
  Harbo, 1999
  Kozloff, 1993
  McConnaughey and McConnaughey, 1985
  Niesen, 1994
  Niesen, 1997
  O'Clair and O'Clair, 1998
  Ricketts et al., 1993
  Sept, 1999
  Snyderman, 1988

Scientific Articles:

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.

Knott, K. Emily, and Gregory A. Wray, 2000. Controversy and consensus in Asteroid systematics: new insights to Ordinal and Familial relationships. American Zoologist 40:3 pp. 382-392

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

Medeiros-Lopes, Elinia, Rocio Perez-Portela, Paulo Cesar Paiva, and Carlos Renato Rezende Ventura, 2016.  The molecular phylogeny of the sea star Echinaster (Asteroidea: Echinasteridae) provides insights for genus taxonomy.  Invertebrate Biology 135:3 pp 235-244

This species is found in many sizes and colors, and may be a species complex.  Photo by Dave Cowles, July 2005

The ossicles on the aboral side form a branching network of small papillate bumps.

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

This distorted individual was trawled from 100-150 m depth in the San Juan Channel.  Photos 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.

This individual is an interesting flesh color. Phot by Dave Cowles 2019

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.