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Phylum: Alderia modesta Class: , Order: : “shield tongue” A sacoglossan sea slug (Loven, 1844) Family:

Description Size—to 8 mm long; Coos Bay specimens to food), or Enteromorpha (Gonor 1961). It has 5 mm. prominent rhinophores and a tail. Color—greenish- to yellowish-tan, black oliviae (= ) has a Y- markings, base ivory. shaped mahogany line from the rhinophores Body—'aeolid': changing; an oblong, flat- to the head midline; it is pale yellow with a bottomed form without tentacles or tail (figs. 1, pink spot behind the eyes. 2). Hermaea vancouverensis is a small (to 5 Rhinophores—reduced, rolled not solid (fig. mm) brown and white slug, more common in 1)7; (Kozloff calls these cephalic projections Puget Sound than in the south; its habitat is 'dorsolateral tentacles,' not rhinophores) eelgrass (Zoctera); its food the diatom lsthmia (Kozloff 1974a). (Williams and Gosliner 1973). Foot—no parapodia (lateral flaps that could Placida dendritica ( =Hermaea ornata) has fold over dorsum); foot extends laterally a long, obvious tail, long cerata, and is pale beyond body (Kozloff 1974a). yellow with dark green lines. It is usually on Cerata—dorsal projections, about 18 (fig. 1), algae Bryopsis or Codium in the rocky in 2 loose branches on both anterior and intertidal, and is found in California and Puget

posterior halves of dorsum (Kozloff 1974a). Sound (Williams and Gosliner 1973). Gills—none. Olea hansineensia (family Oleidae) has Eyes—small, black (figs. 1, 2). only about 10 elongate cerata on its posterior Anus—a long tube originating on a medial dorsum; it is gray, and is found commonly in line, resembling posterior ceratum (McDonald bays in Puget Sound and probably not in 1975). California. Eggs—light yellow, in clear skein (fig. 3). None of these is yellowish tan with small black markings, a tubular anus, and living in Possible Misidentifications Vaucheria. Sacoglossans are a little known group of few species and small size, but which can Ecological Information occur in large numbers. Alderia modesta, like Range—San Juan Island to Elkhorn Slough,

others of the order, feeds on a specific alga, Calif.; Europe (Steinberg 1963). has a wide distribution, and could probably Local Distribution—Coos Bay: South not be confused with other Opisthobranchs. Slough. Sacoglossans resemble superficially the Habitat—found only in mats of alga more well known nudibranchs, but unlike Vaucheria in Salicornia marshes. them, most do not have a circlet of gills, solid Salinity—prefers 16-17 ‰ seawater; cannot rhinophores, or oral tentacles. (One survive in normal seawater or fresh water exception, Stiliger fuscovittatus, has solid (Hyman 1967), although eggs develop in rhinophores; it is tiny (3 mm), transparent either seawater or brackish water. Cerata white with reddish brown patterns, and lives in pulsation rate varies with salinity (Hyman Polysiphonia, a red alga.) 1967). Other Sacoglossans with dorsal cerata Temperature— and rolled rhinophores include, also in the Tidal Level—at higher levels of marsh (Coos family Hermaeidae Bay): about 4.0'. Aplysiopsis smithi (=Hermaeina), greenish Associates—insects; alga Vaucheria. to brownish black with white edges, bulbous cerata, up to 22 mm long; it lives in Quantitative Information Chaetomorpha, Rhizoclonium (its preferred Weight—

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected] Abundance—common in its particular microhabitat, Vaucheria (McDonald 1975).

Life History Information Reproduction—hermaphroditic; eggs laid in September, Coos Bay (this specimen). Growth Rate—to early veliger two days in lab (this specimen). Longevity— Food—alga Vaucheria, exclusively. Predators—some sacoglossans emit nasty repellents (Hyman 1967). Behavior—

Bibliography 1. GONOR, J. J. 1961. Observations on the biology of Hermaeina smithi, a sacoglossan opisthobranch from the west coast of North America. The Veliger. 4:85-98. 2. HYMAN, L. H. 1967. The invertebrates: mollusca. McGraw-Hill, New York. 3. KOZLOFF, E. N. 1974a. Keys to the marine invertebrates of Puget Sound, the San Juan Archipelago, and adjacent regions. University of Washington Press, Seattle & London. 4. MCDONALD, G. R. 1975. Orders Sacoglossa and Nudibranchia, p. 522- 542. In: Light's manual; intertidal invertebrates of the central California coast. S. F. Light, R. I. Smith, and J. T. Carlton (eds.). University of California Press, Berkeley. 5. STEINBERG, J. E. 1963. Notes on the Opisthobranchs of the west coast of North America. The Veliger. 6:68-73. 6. WILLIAMS, G. C., and T. M. GOSLINER. 1973. Range extensions of four sacoglossan opisthobranchs from the coasts of California and the Gulf of California. The Veliger. 16:112- 116.

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]

Digitized 2010 – Last Updated 1979 – E-mail corrections to [email protected]