Laona californica ( Willett, 1944 )

Valdés, Ángel, Cadien, Donald B. & Gosliner, Terrence M., 2016, Philinidae, Laonidae and Philinorbidae (Gastropoda: Cephalaspidea: Philinoidea) from the northeastern Pacific Ocean and the Beaufort Sea (Arctic Ocean), Zootaxa 4147 (5), pp. 501-537 : 503-506

Laona californica ( Willett, 1944)

Figures 1–2

Philine californica Willett 1944: 72 , pl. 14, fig. 4.

Philine sp. 2 Gosliner 1996: 183 , figs. 2.9B, 2.10A.

Type material. Holotype ( LACM 1074 ): off Redondo Beach , California, 91 m depth ( Fig. 1 C).

Other material examined. Six miles southwest of Seal Beach , California (33º36.5’N, 118º06.4’W), 48 m depth, R/ V Velero III ( AHF BS 1135), 16 Feb 1941, 1 shell with dried soft parts, 4.6 mm long ( LACM 41-228.4 ) . North flank of the Redondo Submarine Canyon, Santa Monica Bay , California (33º49.25’N, 118º32.95’W), 208 m depth, R/ V Ocean Sentinel (Southern California Bight Project, stn. 1175), 18 Jul 1994, 1 specimen 6 mm preserved length, leg. Cadien ( LACM 178900 ) .

Description. Live animal unknown. The specimen here examined was contracted and the cephalic shield not visible ( Fig. 1 A). Shell internal, covered with tissue. Shell to 5.5 mm long, elongate, inflated ( Fig. 1 D–E). Spire sunken. Aperture very large, oval, narrowing posteriorly. Outer lip extending above apex. Columella slightly thickened. Inner lip twisted, flattened at intersection with body whorl. Sculpture of fine axial striations crossed by spiral lines forming a net-like pattern. Mature adult individuals often bear sharp raised spines at the intersections of the axial and spiral lines. Shell color white, in some specimens with a light brown band.

Digestive system with an oval buccal mass, surrounded by the central nervous system anteriorly ( Fig. 2 A). Two salivary glands connect with the buccal bulb at the insertion point of the esophagus. Esophagus short, simple, thin-walled. Gizzard and gizzard plates absent. Radular formula 12 x 6.1.0.1.6. Innermost lateral teeth large, hookshaped, smooth, lacking denticles ( Fig 1 B). Outer teeth elongate, smooth. Gizzard plates absent.

Male reproductive system with a long and simple prostate connected to an undiferentiate penis ( Fig. 2 B).

Range. Southern California ( Fig. 3 A). Depth range 48–208 m.

Remarks. Willett (1944) placed Philine californica in the “section” Laona because of the “latticed” or net-like sculpture of the shell. Examination of the radula of two specimen from Seal Beach, California (LACM 41-228.4) and Santa Monica Bay (LACM 178900) confirms this species has a 6.1.0.1.6 radular formula and lacks gizzard plates, which along with the shell sculpture justifies its placement in Laona .

In this paper we examined two specimens, a shell with dried soft parts and a full preserved specimen. The material here examined matches the characteristics of the shell described in the original description by Willett (1944), including the “latticed” or net-like sculpture and the presence of a band of light brown on the shell. This was corroborated with the examination of the holotype (LACM 1074; Fig. 1 C), which is partially broken.

Philine sp. 2 of Gosliner (1996) has a similar radula and also lacks gizzard plates and it is most likely the same species. The preserved specimen described by Gosliner (1996) has a short cephalic shield rounded posteriorly; parapodia short, not extending over heard and posterior shields; posterior shield elongate with elongate skirt-like posterior lobes. The characteristics of this specimen match the features here described for Laona californica .

Laona californica is morphologically similar to the Atlantic species Laona pruinosa (Clark, 1827) , redescribed by Ohnheiser & Malaquias (2013). Similarities between the two species include the shell shape and sculpture, the presence of a brown band on the shell, and the radular morphology. Further research is necessary to fully understand the relationship between these two species.

Figures

FIGURE 1. Laona californica (Willett, 1944). A. Preserved specimen from Southern California (LACM 178900), dorsal view. B. Radula, same specimen. C. Partially broken holotype (LACM 1074). D – E. Ventral and dorsal view of a 4.6 mm long shell from the Southern California (LACM 41 - 228.4).

FIGURE 2. Laona californica (Willett, 1944). Anatomy of a specimen from Southern California (LACM 178900). A. Anterior portion of the digestive system. B. Male reproductive organs. Abbreviations: bb, buccal bulb; cns, central nervous system; e, esophagus; pe, penis; pr, prostate.

FIGURE 3. Distribution maps of the specimens studied in this paper (native species only).