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Scientific NameCommon NameSummary
Solaster dawsoniDawson's sun starSimilar to Stimpson's sun star (Solaster stimpsoni), which usually has a black dorsal stripe running from the central disk, out over each arm. A definitive characteristic is that S. Dawsoni has long, individually defined ambulacral spines, whereas those of S. stimpsoni are shorter, and terminate a common structure (ambulacral spines are found along the edges of the space in which the tube feet are located).

There are two more species which may be confused with this one:

Northern Pacific Sun Star (Solaster endeca) has arms that are "puffy" so that the armpits appear creased. It is primarily a subtidal species. It tends to be orange-tan in color.

Solaster paxillatus is very, very similar to Solaster dawsoni. It tends to have proportionately longer arms, and the spines along the edges of the furled-in "gutter" of the arms tend to be organized in groups of four, rather than three as in this species. Solaster paxillatus is a subtidal species that has been observed on longline gear off Sitka.

This starfish is cannibalistic and a fierce predator. Its primary prey is Solaster stimpsoni, but it also is reputed to be a major predator of Leather star (Dermasterias imbricata). It is regularly found in the shallow subtidal at negative tides, usually among large rocks covered with kelp in areas that aren't exposed to heavy surf or siltation.
Solaster pacificusNorthern Pacific Sun StarMost people still know this species as Solaster endeca ssp. pacificus, but it was raised to the species level in 2010 by C.L. Mah. The nominate ssp., from the Atlantic Ocean, is a starfish predator.

This sun star looks a lot like the more common Dawson's sun star (Solaster dawsoni), except that it has shorter, puffy arms, is more reliably tan-orange in color, and has much shorter adambulacral spines (those are the spines that line the edges of the groove that runs down each arm).

Sometimes, Solaster pacificus has stripes that run down each arm dorsally from the central disk much like in Stimpson's sun star (Solaster stimpsoni), but that species has much longer arms.

This species feeds mostly on sea cucumbers. It is reported to feed in the intertidal (on Long-footed white sea cucumber (Eupentacta pseudoquinquesemita) by Rita O'Clair), but tends to be more subtidal than Solaster dawsoni.
Solaster stimpsoniStimpson's sun starThis species feeds primarily on sea cucumbers. It usually has a dramatic black stripe running down the dorsal side of each arm, from the black central disk. It is a fairly common species in the lower intertidal areas, especially in mixed rock, sediment, and surfgrass areas. A predator of this species is Dawson's sun star (Solaster dawsoni). A mnemonic device for this genus is "stimpsoni is striped, dawsoni is dull."