How to Distinguish from Similar Species: This species is very similar to Leptasterias pusilla but can be distinguished by its large, flat aboral spines, thicker arms, and darker color. L. epichlora is usually mottled and blue-gray, dark green, or indigo and its pedicellariae are few and randomly arranged around the aboral spines. L. aequalis is thought to be a hybrid between L. hexactis and L. epichlora. It has many small pedicellariae randomly arranged around the aboral spines, and a variable aboral color ranging from olive-green, indigo, or gray to coral-red or orange.
Note from Kozloff, 1996: "Specimens keying to Leptasterias hexactis are now believed to belong to three recognizable entities. They are distinguished to some extent by biochemical properties, but the following visible feathres will usually enable one to separate them. Leptasterias hexactis (Stimpson, 1862): small pedicellariae (as distinguished from larger pedicellariae) especially abundant around the aboral spines, generally embedded in tissue either at the base or about midway on the spines, and forming a characteristically wreathlike arrangement; color of aboral surface usually dark olive-green or indigo. Leptasterias epichlora (Brandt, 1835): small pedicellariae few and randomly arranged around the aboral spines; color of aboral surface commonly indigo, blue-gray, or dark green, usually mottled. Leptasterias aequalis (Stimpson, 1862) (believed to be a hybrid of L. hexactis and L. epichlora): small pedicellariae usually numerous and randomly arranged around the aboral spines; color of aboral surface extremely variable, ranging from olive-green, indigo, or gray to coral-red or orange (in our region, the last two colors not often noted in the other two species)."
Additional note: Flowers and Foltz (2001) confirm based on extensive molecular and morphological analysis that the putative species is actually a species complex, all species of which have 6 rays. They identify Leptasterias hexactis, L. alaskensis, L. leptodoma, and possibly L. aequalis, L. aleutica, L. camtschatica, L. pusilla, and L. asteira as separate species, most of which are quite difficult to distinguish morphologically.
Geographical Range: L. hexactis resides as far north as the San Juan Islands and the Strait of Juan de Fuca in Washington south to Santa Catalina Island in the Channel Islands, California.
Depth Range: Middle intertidal zone, often in small beds of mussels (Mytilus californianus). L. hexactis can often be found sheltered under rocks or algae at very low tides or on sunny days.
Habitat: This species is common on rocky shores that are exposed to the surf.
Biology/Natural History: L. hexactis is known to cling very tightly to rocks and it has the ability to conform closely to irregularities in the surface. It is a carnivore and feeds on sea cucumbers, littorine snails, limpets, chitons, small mussels, barnacles, and other small animals, including dead animals. L. hexactis often selects large, hard to capture prey that is often rich in calories. This type of prey supplies most of the sea star’s energy. It is often in direct competition with the much larger sea star, Pisaster ochraceus for food. Breeding occurs from November to April in the Puget Sound. The eggs are yellow, yolky, and about 0.9 mm in diameter. A unique feature of this species is that the broods of eggs (ranging from 52 – 1,491 eggs, variable based on the size of the female) are held by the female in the region of the mouth below the central disk (photo). Because of this, brooding females cannot flatten themselves against the substratum and are only anchored by their outermost tube feet. Unfortunately, they are often dislodged by the waves, losing their eggs. It is necessary for the female to clean the egg masses, and if she does not do this then the eggs quickly die. The presence of the eggs blocks the female’s mouth and she will not feed while brooding, even if there is food readily available. The development of the embryos is direct (photo of juveniles) and L. hexactis individuals will reach maturity within 2 years. Experiments with the behavior of L. hexactis have shown that if the nerve ring is cut at two opposite points, then the animal will walk apart until fission occurs.
Leptasterias hexactis is fleshy, with
and a stronger, coarser skeleton than is Henricia
leviuluscula, another intertidal seastar of similar
It seems to rely much less on its madreporite
to take up seawater for maintaining its tissue fluid balance.
probably uses osmotic uptake of fluid through the papulae
instead (Ferguson, 1994).
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.
Flowers, Jonathan Mark, 1999. Discordant patterns of genetic and morphological variation and their implications for the taxonomy of Leptasterias subgenus Hexasterias of the north Pacific. M.S. Thesis, Louisiana State University. 57 pp.
Flowers, J.M. and D.W. Foltz, 2001. Reconciling molecular systematics and traditional taxonomy in a species-rich clade of sea stars (Leptasterias subgenus Hexasterias). Marine Biology 139: pp 475-483
Foltz, D.W., 1998. Distribution of intertidal Leptasterias spp. along the Pacific North American coast: A synthesis of allozymic and mtDNA data. pp. 235-239 in Rich Mooi and Malcolm Telford (eds), Echinoderms: San Francisco. Proceedings of the Ninth International Echinoderm Conference, San Francisco, California USA 5-9 August 1996.
Foltz, D.W., J.P. Breaux, E.L. Campagnaro, S.W. Herke, A.E. Himel, A.W. Hrincevich, J.W. Tamplin, and W.B. Stickle, 1996. Limited morphological differences between genetically identified cryptic species within the Leptasterias species complex (Echinodermata: Asteroidea). Canadian Journal of Zoology 74: pp 1275-1283
Foltz, David W. and William B. Stickle, Jr., 1994. Genetic structure of four species in the Leptasterias hexactis complex along the Pacific coast of North America. pp. 291-296 in Bruno David, Alain Guille, Jean-Pierre Feral, and Michel Roux (eds). Echinoderms through time. Balkema, Rotterdam.
Kwast, K.E., D.W. Foltz, and W.B. Stickle, 1990. Population genetics and systematics of the Leptasterias hexactis (Echinodermata: Asteroidea) species complex. Mar. Biol. 105: 477-489
Stickle, William B., Jr. and David W. Foltz, 1994. Habitat affinities of species in the Leptasterias hexactis complex along the Pacific coast of the continental United States. pp. 353-358 in Bruno David, Alain Guille, Jean-Pierre Feral, and Michel Roux (eds). Echinoderms through time. Balkema, Rotterdam.
General Notes and Observations: Locations, abundances, unusual behaviors, etc.:
The following set of photos were taken by Dave Cowles of
being used in an experiment by Tamara Loveday. The seastars
collected from rocks near Rosario December 2, 2009. They were
in an aquarium at 8 degrees C. The photos were taken April
Here is a timetable of some events noted by Tamara:
Authors and Editors of Page:
Melissa McFadden (2002): Created original page
Edited by Hans Helmstetler 12-2002, Dave Cowles 2005