Crossaster papposus (Linnaeus, 1767)

Common name(s): Rose star, Snowflake star, Common sun star
Synonyms: photo
Phylum Echinodermata
 Class Asteroidea
  Order Spinulosida
   Suborder Eugnathina
    Family Solasteridae
Crossaster papposus from 100 m depth trawl, San Juan Channel. Diameter approx. 20 cm
(Photo by: Dave Cowles, July 2001)
Description:  This many-rayed seastar has a broad central disk and 8-16 rays, has abundant scattered spines (paxillae) on the aboral surface (photo) but no pedicellariae.  Its color is a rose-red with light pink or white (picture) (sometines yellow or orange).  Up to 30 cm diameter.

How to Distinguish from Similar Species: Solaster stimpsoni and S. dawsoni have much smaller central disks in relation to their total diameter and do not have the abundant aboral spines nor this coloration.  Pycnopodia helianthoides has more rays (when mature), grows larger, and has abundant pedicellariae, plus its rays are very flabby.

Geographical Range: Bering Sea to Puget Sound; Arctic Ocean, North Atlantic Ocean, North Sea, western Baltic sea (circumpolar)

Depth Range: Extremely low intertidal to 1200 m.  Mostly subtidal.

Habitat: Varied.

Biology/Natural History: Diet includes sea pens, nudibranchs such as Archidoris odhneri and Coryphella sp, the scallops Chlamys hastata and C. rubida, bryozoans, and tunicates.  Has been known to attack the seastar Evasterias troschelii and Leptasterias sp.  Predators include the seastars Solaster dawsoni and Pycnopodia helianthoides.  May have the symbiotic polychaete worm Arctonoe vittata.  This species can move relatively fast for a seastar--up to 70 cm/minute.  Spawns March to April.  Juveniles often cluster subtidally in masses of the tubedwelling polychaete Phyllochaetopterus prolifica.  Grow slowly--maximum size is achieved after about 10 years.


 
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References:

Dichotomous Keys:
Kozloff 1987, 1996
 

General References:
Harbo, 1999
O'Clair and O'Clair, 1998

Scientific Articles:
 

Hotchkiss, Frederick C., 2000. On the number of rays in starfish. American Zoologist 40:3 pp. 340-354

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


General Notes and Observations:  Locations, abundances, unusual behaviors:


Various color forms can be found.  Animals from 100 m depth, San Juan Channel.  Photo by Dave Cowles, July 2000



This species has large aboral paxillae, as seen in this closeup.



The edges of the rays have long, spiny paxillae.

Aboral Oral side
A small Crossaster papposus found by divers at about 50 feet depth off Coffin Rocks in 2020. We have rarely found them this shallow, but have now found small individuals at Coffin Rocks for 2 years in a row. Perhaps the extensive die-off of shallower species due to seastar wasting disease opened an opportunity for them to come shallower than they have been in the past. Aboral and Oral views Photo by Dave Cowles, July 2020


Authors and Editors of Page:
Dave Cowles (2005):  Created original page