Edwardsia olguini sp. nov.

Figs. 1, 7; Table 2

Diagnosis. With large, single nemathybomes scattered on column; nemathybomes more numerous proximally than distally. Larger nemathybome nematocysts shorter than 60 μm. Length of whole animal in contraction approximately 10 mm, diameter 2 mm.

Material examined. Holotype: CAS 175216, San Diego, California, 33°34.064’N 118°00.750’W, July 1999, 91 m. Paratype: CAS 175252, collected with holotype.

External anatomy. Tentacles filiform, 16, in two cycles of eight. In life, tentacles translucent white, with irregularly arranged yellow to white blotches; oral surface of each tentacle with reddish longitudinal stripe extending length halfway from tip (JL pers. obs.). Scapus beige, with large, scattered nemathybomes (Figs. 7 A–D). Periderm thin, loose, of relatively large grains. Furrows of mesenterial insertions more prominent distally than proximally. Physa naked, small, bearing central pore, often retracted inside scapus so that aboral end appears covered in periderm (Figs. 7 C, D).

Internal anatomy and histology. Parietal and retractor muscles relatively weak (Figs 7 E, F). Retractor muscle branched on both surfaces of mesentery but without distinct pennon (Fig. 7 F). Branches of retractor muscle widely spaced, variable in height and degree of ramification. Parietal muscle trianguloid, with central lamella slightly thicker than lateral branches (Fig. 7 E). No examined specimens contained gametes.

Nemathybomes relatively large, single, scattered, protrude above epidermis and periderm (Figs. 7 A–C). Epidermis and mesoglea thin. Epidermis thicker and more glandular on physa than scapus.

Cnidom. Spirocysts, basitrichs, microbasic p ­mastigophores (Figs. 7 G–N; see Table 2 for size and distribution).

Etymology. Named for John M. Olguin, director emeritus of the Cabrillo Marine Museum, San Pedro, California, in recognition of his enthusiasm and skill at communicating his love of the sea and marine life to generations of marine biologists.

Distribution and habitat. Throughout Southern California Bight shelf, 10–100 m, not extending into central California (JL, pers. obs.); in fine, silty sediments.

Similar species. Relatively few species of Edwardsia have nemathybomes containing nematocysts of two sizes (England 1987). In southern California, there are three: E. californica, E. handi, and E. olguini . Edwardsia olguini is distinguished from all other species of Edwardsia with 16 tentacles and two sizes of nemathybome nematocysts in having the smallest nemathybome nematocysts (see differential diagnosis of E. handi, above). Because its physa is small even in expansion, E. olguini can easily be mistaken for a member of Scolanthus, but its nemathybomes contains two size classes of nematocysts, and the aboral end lacks nemathybomes and periderm.

Remarks. None.