Dendronotus rufus O’Donoghue, 1921

Fig. 7

Dendronotus rufus O’Donoghue, 1921:190– 192; Pl. 3, Figs 25–27; Pl. 4, Fig. 48; O’Donoghue, 1922:125; Robilliard, 1970: 456–460, Figs 4–6, 16–18, Pl. 63, Fig. 32.

Behrens, 1980:76; Behrens & Hermosillo, 2005:95; Lamb & Hanby, 2005: 262.

Dendronotusfrondosus sensu Odhner, 1936 (part.) non Ascanius, 1774.

Extended diagnosis. Body relatively narrow. Six to nine pairs of branched dorsolateral appendages. Fiveappendages of oral veil. Five appendages of rhinophoral stalks. Lateral papilla of rhinophoral sheaths present. Rhinophoreswith 19–24 lamellae. More than 30 lip papillae. Basal colour from red to grayish white, white specimens commonly have remarkable differences in colour of dorsolateral appendages (which can be brick red to dark red). Dorsal processes of jaws inclined posteriorly at approximately 70° to the longitudinal axis of the jaw body and 0.45 of its length. Masticatory processess with ridge-likestructures and smaller denticles. Radula with up to 35 rows of teeth. Central tooth with up to 28 small denticles (usually smaller) with ribs or shallow furrows, never completely smooth. Upto 16 lateral teeth with up to seven denticles. Ampulla relatively narrow, long, with several windings and loops. Bursa copulatrix large, oval. Seminal receptaculum small, placed distally at a moderately short distance from the vaginal opening. Prostate discoid with numerous alveolar glands (at least more than 50). The vas deferens is very long, penis long, narrow, looped several times. Body length up to 170 mm.

Distribution. NE Pacific, from southern Alaska to Washington state, Canadaand USA.

Bathymetry. 7–38 mdepth.

Remarks. This is among the largest Dendronotus species. According to the radular formulait issimilar to D. lacteus and molecular data confirm D. rufus as a sister species to D. lacteus (fig. 1). In its biogeographical pattern it reveals quite narrow endemism, so far known only from southern Alaska to Washington state.