Rose Star – No Two Alike
One species. So many colours.
That’s beauty. That’s biology.
Rose Stars have such diversity in colour and pattern, that the species is also known as the “Snowflake Star”; a name suggesting that no two are alike.
Am I trying to make some sort of point as it applies much more broadly? Why, whatever would make you think that? 😉
Surely we humans rejoice in the beauty of diversity?
Please see additional photos (and slideshow) below to get a further sense of the diversity, the beauty, and the perfection.
- Crossaster papposus to 34 cm but in British Columbia the maximum size is believed to be 17 cm.
- They can live to at least age 20. Species is slow growing. Maximum size is reached around age 10.
- Even the number of arms varies. Most Rose Stars have 11 arms but number ranges from 8 to 16. From personal communication with zoologist Neil McDaniel: ” I did counts of 63 images I had on file [all from British Columbia’ and nearly 90% (87%) had 11 arms, about 10% had 10 and 3% had 12.”
- They are SPEEDY! Zoologist Neil McDaniel clocked them at 50 cm/min. Larger individuals were documented to travel over 5 meters in 12 hours. They are serious predators but may also be speedy because they are known to be prey for Sunflower Stars and Morning Sun Stars.
- Diet is known to include sea pens, nudibranchs, bryozoans, bivalves (e.g. clams), juvenile urchins and tunicates. Their diet is likely broader than this as they are not picky eaters. I often see them in rocky habitats covered by coralline algae species (see photo below) and believe that is, at least in part, because the prey there include Orange Social Tunicates. They are one of the few species of sea star known to feed on nudibranchs. They also are known to have attacked other sea star species – Mottled Stars and Six-rayed Stars
- How they feed: When they feel their prey, and are hungry, they retract their sensory tube feet (tube feet at the tips of their arms), and then stretch up on their tippy toes (extending their terminal tube feet) to be higher and able to “pounce” on their prey when on the ocean bottom. Smaller prey are swallowed whole. Larger prey are held with the tube feet and, as is the case with other sea star species too, they evert their stomach OUT OF THEIR BODIES and into or over their prey.
- Research supports that Rose Stars can sense potential prey and other sea stars by smell (distance chemoreception).
- In the photos below you will also see the intricacy of the surface of sea stars. You will see:
- Pedicellaria = amazing little structures that can nip off the tube feet of other species of sea star e.g. the predatory Morning Sun Star (Solaster dawsoni).
- The tufts are “papulae”. They are the gills / respiratory organs of the sea star. They can retract into the surface of the sea star’s body.
- Range: Bering Sea to Puget Sound; Arctic Ocean, North Atlantic Ocean, North Sea, western Baltic Sea.
- Depth: Found from the shallows of the intertidal to ~1,200 m. Believed to more often be in low current areas.
- I saw little impact on this species from Sea Star Wasting Disease around NE Vancouver Island BUT Rose Stars were hit very badly in 2014 in other areas e.g. Sechelt Inlet, British Columbia (McDaniel, pers. comm.). See photo at the end of the blog. The species seems to be rebounding, unlikely Sunflower Stars which remain devastated across their range.
The next 3 images are of the same individual.
- Lambert, Philip; Sea Stars of British Columbia, Southeast Alaska, and Puget Sound
- McDaniel, Neil, pers. comm. 2020-06-06
- McDaniel, Neil; Sea Stars of the Pacific Northwest
- Sloan NA, Northway S. 1982. Chemoreception by the asteroid Crossaster papposus (L). J Exp Mar Biol Ecol 61:85–98.
- Wallawalla.edu; Crossaster papposus
4 Responses to “Rose Star – No Two Alike”
Hi Jackie, Great photos!
Can you settle a debate for us? We notice that every sea star has a white spot near the middle of it’s body; what is this feature?
Hello Gary, All sea stars need an intake for their water vascular system. That round structure is the madreporite (or sieve plate).
Not only ALL sea star species but ALL Echinoderms have this (sea cucumbers, urchins, etc).
“Sea stars (and other echinoderms) have a unique circulatory system that basically processes and circulates sea water throughout the animal’s body. Imagine if your body was basically just OPEN to sea water and funneled through a bunch of tubes that make your tube feet and stomach work.
That’s basically how starfish (and their relatives) get around and hold themselves up. Other than the calcium carbonate endoskeleton in echinoderms-the only other thing that holds them up?? Water pressure.
Basically, the softer the skeleton, the more dependent the animal is on its surroundings to hold up its body . . . But even an open system like this needs to have an intake valve to process water for the animal’s basic bodily functions-like movement and internal circulation and etc… That is what the madreporite is for.”
More intel here
By the way, is your blog searchable for previous posts (e.g. sea star wasting disease)?
Cheers, Gary at HMB
On Sun, Jun 7, 2020 at 9:47 AM The Marine Detective wrote:
> The Marine Detective commented: “Hello Gary, All sea stars need an intake > for their water vascular system. That round structure is the madreporite > (or sieve plate). Not only ALL sea star species but ALL Echinoderms have > this (sea cucumbers, urchins, etc). “Sea stars (and other echinode” >
Absolutely. There are tags in the marine and you can also use the search within the blog or use Google to search the topic and “The Marine Detective”. Here it the direct link re. Sea Star Wasting Disease https://themarinedetective.com/2013/11/10/wasted-what-is-happening-to-the-sea-stars-of-the-ne-pacific/