Diaulula odonoghuei Steinberg 1963

Common name(s): Spotted dorid

Synonyms: part of Diaulula sandiegensis,  Doris echinata Dialula odonoghuei
Class Gastropoda 
Family Discodorididae 
Two Diaulula odonghuei found at Cape Flattery
(Photo by: Dave Cowles, July 2012 )

Description:  The anus is on the midline of the dorsum, 1/2 to 3/4 of the way from the anterior end. Gills in a circle around the anus. Though the dorsum has small papillae (visible only with a microscope), the only conspicuous dorsal outgrowths are the rhinophores and the gills. The gills can be completely retracted. The rhinophores are relatively stout. The dorsum is white, gray, light or dark brown, or occasionally orange. with large, scattered brown spots or rings. These spots occur both on the central part of the dorsum and out to the mantle edges. Number of spots may range from around 23 to 234 (mean of 78)(Lindsay et al., 2016).

How to Distinguish from Similar Species:  This species appears very similar to D. sandiegensis and until recently was considered to be the same species. The most clear distinction is that this species has dorsal spots on both the central portion of the dorsum and out to the mantle edges, while D. sandiegensis does not have spots or rings near the mantle edges. Also, the spots on D. sandiegensis are usually (not always) rings, while those on  this species are usually (not always) solid spots. Also, in the Pacific Northwest this species is usually intertidal while D. sandiegensis is mainly subtidal here.

Geographical Range:  Japan and Korea through Alaska south to Bodega Bay (northern California).

Depth Range:  Mostly intertical in the Pacific Northwest

Habitat:  Mostly rocky intertidal on the open coast and in bays 

Biology/Natural History:  As individuals of this species grow, they accumulate more dorsal spots, and the dorsal spots also grow larger (Lindsay et al., 2016). Individuals of this species appear to feed primarily on purple Haliclona sponges. Molecular analysis indicates that there is little gene exchange between the populations on the west coast of North America and those in Asia.

Until recently this species was considered to be a variant of Diaulula sandiegensis. Lindsay et al., 2016 established molecularly and confirmed by morphology and breeding choices that the species is separate from D. sandiegensis.



Dichotomous Keys:
  Kozloff keys this species in combination with D. sandiegensis)

General References:

Scientific Articles:
  Lindsay, Tabitha, Julie Kelly, Anton Chichvarkhin, Sean Craig, Hiroshi Kajihara, Joshua Mackie, and Angel Valdes, 2016. Changing spots: pseudocryptic speciation in the North Pacific dorid nudibranch Diaulula sandiegensis (Cooper, 1863) (Gastropoda: Heterobranchia). Journal of Molluscan Studies 82:4 pp 564-574. doi: 10.1093/mollus/eyw026

Web sites:

General Notes and Observations: Locations, abundances, unusual behaviors:

Authors and Editors of Page:
Dave Cowles (2019):  Created original page
CSS coding for page developed by Jonathan Cowles

Salish Sea Invertebrates web site provided courtesy of Walla Walla University