Botrylloides violaceus Oka, 1927

Lambert, Gretchen, 2003, New records of ascidians from the NE Pacific: a new species of Trididemnum, range extension and redescription of Aplidiopsis pannosum (Ritter, 1899) including its larva, and several non-indigenous species, Zoosystema 25 (4), pp. 665-679 : 675-676

Botrylloides violaceus Oka, 1927

Botrylloides violaceus Oka, 1927: 608 , 609 (type locality: Japan). — Saito et al. 1981: 360-364, figs 3, 4, 5b, redescription.

MATERIAL EXAMINED. — North America. Many marinas in Puget Sound, the San Juan Archipelago and southern Vancouver Island (specific sites available from the author), VIII.1998 - IX.2001, numerous samples.

USA, 16 km N of Seattle, WA, Edmonds Marina, 0.5- 2.0 m, 21.VIII.1998, several colonies with larvae on floats and ropes ( CASIZ 162515, 3 colonies) ( MNHN S1 BOT A 32, 3 colonies).

Willapa Bay, WA (A. Cohen et al. 2001), on oysters and marina floats, 22. V.2000, many.

DISTRIBUTION. — NE Pacific: Alaska to Baja California ( Lambert & Sanamyan 2001); NW Pacific: Vladivostok ( Sanamyan 2000); NW and NE Atlantic, Mediterranean ( Zaniolo et al. 1993), Japan ( Nishikawa 1991).

DESCRIPTION

All specimens agree in every respect with the detailed description given by Saito et al. (1981) for the Japanese colonies. The zooids are aligned vertically in the tunic, in round, oval or elongated systems or sometimes crowded together so that the systems are obscured. The colonies may be purple, light lavender, any shade of yellow or orange, brown, or even nearly colorless, but in all cases the entire colony is all of one color. The tunic is soft, easily torn, and the zooids are then easily freed from the tunic. There are 10-11 rows of stigmata; the second row of stigmata is incomplete on both sides. The most distinguishing character is the large larva (about 1 mm trunk length) with 24-32 lateral ampullae. The larvae are brooded in a separate brood sac that is nourished by the vascular system while the parent zooid dies.

REMARKS

Botrylloides violaceus was described from Japan by Oka in 1927 and redescribed by Saito et al. (1981). Tokioka (1953) characterized it as “the commonest botryllid in Japanese waters”. It appeared on both the US Atlantic and Pacific coasts at least 30 years ago. The earliest confirmed description of it was by G. Freeman (cited by Berrill 1975) who observed the unusual larva in colonies collected in San Diego but misidentified it as Botryllus schlosseri (Pallas, 1766) . Fay & Vallee (1979) also observed it in southern California but misidentified it as Botrylloides diegensis Ritter & Forsyth, 1917 . B. violaceus has a very long breeding season and is a precocious species that begins to produce larvae when the colony is still quite young and small. Following the classification of Saito et al. (2001), the genus Botrylloides is retained here for those botryllids in which the testes are located anterior to the ovaries. An additional non-indigenous species, Botryllus schlosseri , is also common in many areas of Washington state from Olympia to the Canadian border at Blaine ( Mills et al. 2000). Locations can be found in C. S. Cohen et al. (1998) and the unpublished reports by A. Cohen et al. (1998, 2001).