Edwardsia profunda Daly & Ljubenkov, 2008, sp. nov.

Edwardsia profunda sp. nov.

Figs. 1, 8; Table 2

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Edwardsia californica (McMurrich, 1913): pro parte Fautin 1998 Diagnosis. With large, clustered nemathybomes in longitudinal rows between macrocnemes. Length of whole animal in contraction 19–34 mm, diameter 4–5 mm.

Material examined. Holotype: CAS 175213, Los Angeles County, California, LA­3 dumpsite station CN1, rep. 2, 425 m. Paratypes: CAS 175211, Monterey Bay, California, Southern Cross ALT 1 Sta. 1.1200s.1, 12­Sep­ 1999, 500 m; CAS 175215, San Diego County, California, OCSD Historic Sta. B47, 28­Aug­ 1983, 447 m; CAS 175214, San Diego County, California, OCSD Historic Sta. B41, 31­Jul­ 1983, 303 m; SBMNH 422859, Santa Maria Basin, California, MMS Phase II Sta. R­7, 34º52.90’N, 121º10.30’W, October, 1986, 565 m; SBMNH 422856, Pacific Ocean, Santa Maria Basin, California, MMS Phase I Sta. 78, 34º18.78’N, 120º49.30’W, 9­Nov­ 1983, 762 m; SBMNH 422857, Santa Maria Basin, California, MMS Phase I Sta. 56, 4º30.32’N, 121º01.02’W, 5­Jan­ 1984, 900 m (2 specimens).

External anatomy. Tentacles filiform, 14–16, retracted inside column in all specimens examined. Scapus with clusters of nemathybomes in broad longitudinal rows between macrocnemes (Fig. 8 B). Periderm thin, fine, may be visible only in mesenterial furrows. Physa naked, bulbous, typically rosette­like, with pronounced mesenterial insertions (Figs. 8 A, D).

Internal anatomy and histology. Parietal and retractor muscles strong (Figs. 8 C, G). Retractor muscle branched on both surfaces of mesentery, with small pennon and numerous short branches on secondary surface of mesentery (Fig. 8 C). Parietal muscle ovoid, with many lateral branches and relatively broad central lamella (Fig. 8 G). Lateral branches of parietal muscle ramified, those closest to body wall grouped, attached to the mesentery by single, slightly longer lamella. No examined specimens contained gametes.

Nemathybomes large, forming clusters of multiple nemathybomes adjacent to one another; clusters sunken into mesoglea and protruding slightly into epidermis (Fig. 8 B). Epidermis of scapus thin; mesoglea thick, bi­layered, becoming thinner and homogenous proximally.

Cnidom. Spirocysts, basitrichs, microbasic p ­mastigophores, pterotrichs (Figs. 8 E–F; H–L; see Table 2 for size and distribution).

Etymology. The species epithet is an adjective based on the Latin root “profund­,” referring to the habitat of the species, and should be translated as “the deep Edwardsia.”

Distribution and habitat. Slopes and basin floors of southern California and Monterey Canyon, at depths exceeding 300 m, in fine, high­organic content sediments.

Similar species. In having 16 tentacles and large, clustered nemathybomes, E. profunda resembles E. carlgreni Williams, 1981, E. delapiae Carlgren & Stephenson, 1928, and E. elegans Verrill, 1869. These three species are known from intertidal and shallow shelf depths in the North Atlantic (Fautin 2007). The nemathybome nematocysts are considerably smaller in E. profunda than in E. elegans (67–84 and 67–101 μm: Carlgren 1931); the tentacle basitrichs are considerably longer in E. profunda than in E. delapiae (19–22 μm: Stephenson 1928) or E. carlgreni (17–19 μm: Carlgren 1931).

Remarks. The three deeper­water lots Fautin (1998) identified as E. californica (SBMNH 422856, 422857, 422858) belong to E. profunda.