UC specimens and range limits for Derbesia marina

• Blue markers: specimen records
• Yellow marker: type locality, if present
• Red markers: endpoints of range from literature

View map from the Consortium of Pacific Northwest Herbaria

Notes: Worldwide. On the west coast, from Amchitka Island, Alaska (MICH-728315), Vancouver Island, British Columbia to Sulphur Bay, Clarion I., Revillagigedo Islands, Mexico, MICH-727372. Apparently disjunct (or not collected) between Cape Arago, Oregon and Mendocino Co. Spotty distribution in California between Monterey and the southern California bight.

Status: Specimens of this species from the west coast have not been analyzed with molecular tools, but should be. Derbesia prolifera has been reported but not confirmed.

Habitat: Low intertidal-subtidal

Life History: Not completely known for Pacific coast populations, but probably same as in Europe, where unisexual spherical gametophytes ("Halicystis ovalis") alternate with a siphonous sporophyte (Derbesia marina) by means of biflagellate anisogametes and stephanospores (Kornmann 1938; Neumann 1974; Neumann 1969b; Neumann 1967).

Search Sequences in GenBank

Illustration from DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California

Derbesia Solier 1846

With features of the family. Certain species with pyrenoids, others without. Some species reported to lack gametangial stage under culture conditions; many species known in nature that have never been matched to a gametangial stage.

Derbesia marina (Lyngb.) Sol.

Vaucheria marina Lyngbye 1819: 79. Derbesia marina (Lyngb.) Solier 1846: 452; Setchell & Gardner 1920b: 165; Smith 1944: 71. Gastridium ovale Lyngb. 1819: 72. Halicystis ovalis (Lyngb.) Areschoug 1850: 447; Hollenberg 1935: 782; 1936: 1; Kornrnann 1938: 464.

Sporangial stage (Derbesia): Thalli tufted, to 1.5 cm tall, attached by irregularly branched, prostrate and often penetrating branches; erect branches 50-65 µm diam., frequently branched without percurrent axes; chloroplasts without pyrenoids; sporangia lateral, obovoid to obpyriform, 100-160 µm diam., 150-200 µm long, on brief pedicels with a biconcave partition; zoospores mostly 20-30 per sporangium, with anterior crown of flagella, germinating directly and slowly developing into sexual phase.

Frequent on rocks or on the chiton Cryptochiton stelleri, or on encrusting coralline algae, low intertidal on exposed rocky shores to subtidal (23 m), Sitka, Alaska, to La Jolla, Calif. Also N. Europe. Type locality: Faeroes.

Gametangial stage ("Halicystis ovalis"): see below.

Gametangial Stage of Derbesia marina

"Halicystis ovalis" (Lyngb.) Aresch. Gastridium ovale Lyngb. 1819: 72. Halicystis ovalis (Lyngb.) Areschoug 1850: 447.

Thalli spherical, coenocytic, 2-10(15) mm diam., with rhizomelike basal part penetrating encrusting coralline algae; protoplasm forming thin layer next to wall, with chloroplasts next to the large vacuole and numerous nuclei next to wall; reproduction by anisogamous biflagellate gametes; gametangial areas irregularly band-shaped, formed in spherical portion, not cut off by cell wall from vegetative portion; numerous gametes liberated periodically and forcefully through 1 or more pores.

Frequent to locally abundant, low intertidal (on Lithophyllum spp. on exposed rocky shores) to subtidal (23 m), Silver Bay, Alaska, to Pta. Eugenio, Baja Calif.; in Calif., known chiefly south of Pt. Lobos (Monterey Co.) to Santa Catalina I. Widely distributed in N. Hemisphere. Type locality: N. Europe.

Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.

Notes: While the gametophyte is readily identified, the sporophyte is less so; both phases are poorly represented by herbarium specimens.