Asterias rathbuni
From Wikipedia, the free encyclopedia
| Asterias rathbuni | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Forcipulatida |
| Family: | Asteriidae |
| Genus: | Asterias |
| Species: | A. rathbuni |
| Binomial name | |
| Asterias rathbuni (Verrill, 1909) Djakonov, 1950 | |
| Synonyms[1] | |
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Asterias rathbuni is a starfish native to the Pacific coasts of Alaska in the United States[2][3] and Far East Russia. There are two subspecies.[4]
Intraspecific variation
According to Addison Emery Verrill it may have first been collected in 1881-1883 by the International Polar Expedition to Point Barrow, Alaska, where some starfish of the genus Asterias were collected at a depth of 7 fathoms on a pebbly seabed just off of Port Clarence.[3][5] The species was first described by Verrill as Allasterias rathbuni in 1909 as the type species for his new genus Allasterias.[1][2][6] He commemorated Richard Rathbun, curator of marine invertebrates at the United States National Museum, in the specific epithet. He described three varieties: the nominate, var. anomala and var. nortonensis (named after the Norton Sound in Alaska). The variety anomala was described by Verrill in this 1909 work from St. Michael Island in the southeast of Norton Sound.[2] In 1914 Verrill raised var. anomala to an independent species, Allasterias anomala.[2] In 1923 Walter Kenrick Fisher synonymised Allasterias with Asterias,[6][7] and in 1930 synonymised anomala, rathbuni and rathbuni var. nortonensis with Asterias amurensis.[6][8] In 1950 Alexander Michailovitsch Djakonov reinstated the taxon as A. rathbuni, and subsumed A. anomala under A. rathbuni as forma anomala, accepting all other of Verrill's forms.[1][4] Fisher synonymised the variety nortonensis with A. amurensis in 1930; the World Register of Marine Species maintains this classification despite following Djakonov's recognition of the variety as a form of A. rathbuni, and Jangoux and Lawrence also largely following Djakonov.[6][8][9]
Verrill originally recognised three varieties in 1909: the nominate, var. anomala and var. nortonensis.[2] Fisher considered all three to be synonyms of Asterias amurensis sensu stricto. Regarding var. nortonensis, he stated that it is only known from five specimens recovered from Norton Bay in Alaska, these varied in spination, with the type being the most divergent among them (the only specimen Verrill was able examine), but all within the diversity to Russian specimens of A. amurensis, and thus maintaining recognition for this taxon was unwarranted.[8] In 1950 Djakonov described one new subspecies, crassispinis, and recognised four formae of the nominate subspecies: the nominate, alveolata, anomala and nortonensis.[4] Jangoux and Lawrence followed Djakonov in 2001, but recognised f. anomala as a synonym of the nominate, and classed alveolata and nortonensis as varieties of A. rathbuni ssp. rathbuni.[6]
Two subspecies are accepted in the World Register of Marine Species by Christopher Mah as of 2008:[1]
- A. rathbuni ssp. rathbuni (Verrill, 1909)
- A. rathbuni ssp. crassispinis Djakonov, 1950 - Found in the Sea of Okhotsk[4][6] and around Sakhalin. The arm length is up to 14.6cm.[4]