Mediaster aequalis Stimpson 1857

• Main Author: Mah, Christopher L.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Asteroidea; Valvatida; Goniasteridae; Mediaster; Mediaster aequalis; Alaska; Aleutian Islands
• Online Access: https://zenodo.org/record/6055246; https://doi.org/10.5281/zenodo.6055246

Mediaster aequalis Stimpson 1857 Stimpson 1857: 530; Fisher 1911: 198; Ziesenhenne 1937: 214; Alton 1966a: 1682, 1701; Blake 1973: 49; Kozloff 1987: 449, 450, 453 (key & checklist); Maluf 1988: 34, 118; A.M. Clark 1993: 262; Lambert 2000: 57, 67; Lamb & Hanby 2005:327; Mah 2007b: 927(in key) (as Mediaster aequalis) Dujardin & Hupé 1862: 365 (as Ophidiaster) Occurrence. Alaska / Aleutian Islands, British Columbia, Washington, Oregon, California (including Cordell Bank) to Southern California and Gulf of California (Cortez Seamount), intertidal to 1500 m. Comments. Although three specimen lots are outlined below, they all represent sampling from one locality. This record of this primarily shallow-water species below 1000 m suggests that it is the lower limit of this species’ distribution. The largest of those sampled had an R=2.6 with only three furrow spines. Larger, shallower individuals display up to five furrow spines. Pedicellariae were not observed on these smaller individuals (R<2.0) which also display three furrow spines. These specimens also showed a more weakly stellate body form (R=~1.8) versus the R/r=2.6 as outlined by Fisher (1911). One specimen of Mediaster aequalis collected from Cortez Bank in the Gulf of California from 91.4 m showed a stellate body from (R/r=2.3) but with sharply triangular arms, four furrow spines (at R=2.8), and a strongly expressed superomarginal plate series which occupies approximately 28% of the distance r (disk center to edge of interradius) whereas more northern individuals display superomarginals which occupy only 14% of the distance r. Material examined. CASIZ 117511, 2–3 nautical miles SW of Pt. Soberantes, Monterey County, California. 36º25’7N, 120º58’20”W, 1280–1500 m (700–820 fms). Coll. R / V Searcher. 7 wet spec. R=1.6, r=0.8; R=1.1, r=0.6; R=1.2; r=0.6; R=1.7, r=0.8; R=1.4, r=0.7; R=1.8, r=0.9; R=2.6, r=1.4. CASIZ 117603, 2–3 nautical miles SW of Pt. Soberantes, Monterey County, California. 36º25’7N, 120º58’20”W, 1280–1500 m (700–820 fms). Coll. R ...