Stiliger fuscovittatus Lance, 1962

Common name(s): Brown-streak stiliger, streaked stiliger

Synonyms: Stiliger fuscovittatus
Phylum Mollusca 
Class Gastropoda 
Family Stiligeridae 
Stiliger fuscovittatus, about 4 mm long, found in the Rosario seawater system.  The animal is crawling rapidly and very difficult to photograph.
(Photo by:  Dave Cowles, August 2014)

Description:  As a Sacoglossan, this nudibranch-like species has no external shell nor cephalic shieldRhinophores, if present,  are solid or rolled, not perfoliate, with longitudinal ridges, or with vertical pinnate plumes, and the clavus is not distinct from the stalk.  Rhinophores, if present, cannot be retracted into a sheath.  The dorsum of Sacoglossans may or may not have elongated outgrowths such as cerata.  The anus is on the dorsal midline, just posterior to the rhinophoresStiliger fuscovittatus has cerata and well-developed, simple, solid, tapered rhinophores but the foot is not expanded into parapodia.  The large cerata are on both the anterior and posterior half of the dorsum.  The body is approximately cylindrical, and the posterior foot tapers back to form a pointed tail.  The cerata and the dorsum have a reddish-brown pattern of spots and irregular lines on a grayish-white background.  Some references say that two reddish-brown lines run posteriorly from the rhinophores and others say there may be a brownish line running down the rhinophore stalk and forward between the eyes.  These features were not seen on this individual.  Total length up to 8-10 mm.

Although much of the descriptions fit this species well, this identification is still tentative since I see no reddish-brown lines behind the rhinophores or the lines down the rhinophores forward to between the eyes.

How to Distinguish from Similar Species:  Hermaea oliviaeHermaea vancouverensis and Placida dendritica have rolled rhinophoresAlderia modesta has no rhinophoresPlacida dendritica has up to 50 cerata, which have green extensions of the gut into them.

Geographical Range:  Ketchikan, Alaska to Bahia de Los Angeles, Baja California, Mexico

Depth Range: [Presumably intertidal and shallow subtidal]

Habitat:  On filamentous red algae, mainly in bays.

Biology/Natural History:  Usually found on the red alga Microcladia or sometimes other filamentous red algae (such as Callithamnion in Monterey Bay, CA).  Can be abundant, especially in April-June.  The eggs are laid in spiral strings with individual sausage-shaped sections in late spring-summer.



 

References:

Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996

General References:
  Behrens, 1991
  Morris et al., 1980

Scientific Articles:
 

Web sites:


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

Another view
Another view as the animal charges (streaks?) around the dish.  Note the thick cerata with the reddish-brown pattern.
 


Authors and Editors of Page:
Dave Cowles (2014):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)

Salish Sea Invertebrates web site provided courtesy of Walla Walla University