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Aegires albopunctatus
Aegires albopunctatus MacFarland, 1905
This beautiful little species was perhaps whimsically named by Frank Mace MacFarland in his first taxonomic article on the dorid nudibranchs of Monterey Bay, California. At first glance, it is a vivid white, with numerous small dark brown to black spots. Only under close examination will one see the minute white-on-white spots for which the species was named!
Aegires albopunctatus is definitely a "warty" slug--the dorsum is covered with numerous small cylindrical protuberances. As MacFarland (1966) wrote, "Dorsum rounded, thickly set everywhere with short blunt tubercles, cylindrical or with slightly expanded apices, arranged in irregular longitudinal rows."
This elongate nudibranch reaches about 25 mm in total length. "Body arched, limaciform, not at all depressed, robust and firm to the touch owing to abundant spicules of the integument. Highest and broadest immediately in front of the branchial plumes, from which it slopes rapidly downward behind into the broad bluntly pointed tail, in front more gradually to the head" (MacFarland, 1966).
It has simple rhinophores, each within a sheath of 5-6 rounded tubercles.
The radula consists of 15-22 rows of 17-24 teeth per half row; there is no rachidian. Radular teeth are hamate. I have described (see Bertsch, 1980 and 1983) the feeding of Aegires albopunctatus on the calcareous sponges Leucetta losangelensis (De Laubenfels, 1930), and Leucilla nuttingi (Urban, 1902). It is especially significant that Aegires albopunctatus feeds upon calcareous sponges. First, Altimira & Ros (1979) reported that the European species Aegires sublaevis Odhner, 1932, feeds on the calcareous sponge Clathrina ceriacea. Secondly, of the 25 genera of Porifera known as prey items of the other species of dorid nudibranchs from the northeast Pacific coast, all belong to the Class Demospongiae. The other sponge-feeding genera of dorids (e.g., Chromodoris, Archidoris, Anisodoris, etc.) are all members of Cryptobranchia. However, species of Aegires and Notodoris belong to Phanerobranchia, the dorid group which normally preys on ascidians and bryozoans, and has a distinctly different radular tooth morphology. However, the radula of Aegires has the morphology of typical sponge-feeding cryptobranchs: rows of simple, hamate teeth. The evolutionary relationships of this group may help us to better understand dorid phylogeny.
The range of this species is from Porcher Island, British Columbia,
Canada, to Estero de Coyote (near Punta Eugenia), Baja California Sur,
Mexico (Behrens, 1991); in a disjunct distributional record, this species
has also been reported from inside the Gulf of California at Bahía de los
Angeles (Lance, 1966; Steinbeck and Ricketts, 1941).
Altimira, C., and J. Ros. 1979. Algunos moluscos marinos de las Islas
Canarias. Vieraea 8 (1): 3-12.
Behrens, David W. 1991. Pacific coast nudibranchs. Sea Challengers,
Monterey, 107 pp.
Bertsch, Hans. 1980. The nudibranch Aegires albopunctatus
(Polyceratacea: Aegiretidae) preys on Leucilla nuttingi (Porifera:
Calcarea). The Veliger 22 (3): 222-224.
Bertsch, Hans. 1983. Estudios de ecosistemas bentónicos a lo largo de la
costa noroccidental de Baja California, México: Distribución y presa de
varios invertebrados marinos. Ciencias Marinas 8 (2): 91-123.
Lance, James R. 1966. New distributional records of some northeastern
Pacific Opisthobranchiata (Mollusca: Gastropoda) with descriptions of two
new species. The Veliger 9 (1): 69-81.
MacFarland, Frank Mace. 1905. A preliminary account of the Dorididae of
Monterey Bay, Califronia. Proc. Biol. Soc. Washington 18: 35-54.
MacFarland, Frank Mace. 1966. Studies of opisthobranchiate mollusks of
the Pacific coast of North America. Mem. Calif. Acad. Sci. 6: xvi + 546 pp.
Steinbeck, J., and E.F. Ricketts. 1941. Sea of Cortez: a leisurely
journal of travel and research. Mamaroneck, N.Y., Paul R. Appel (1971
reprint). 598 pp.
Taxonomic Information and Photos courtesy of Dr. Hans Bertsch
Assoc. Prof. |
