Suavotrochus lubricus ( Dall, 1881 )

Cavallari, Daniel C., Salvador, Rodrigo B., Dornellas, Ana P. S. & Simone, Luiz R. L., 2019, Calliostomatidae, Colloniidae, Margaritidae, and Solariellidae (Gastropoda: Trochoidea) collected by the Marion Dufresne (MD 55) expedition in southeastern Brazil, with description of a new species of Calliostoma, Zootaxa 4609 (3), pp. 401-428 : 423

Suavotrochus lubricus ( Dall, 1881)

( Fig. 9 H–L)

Synonymy see Quinn (1979). Complement: Margarita lubrica Dall, 1881: 44 . Solariella (Suavotrochus) lubrica: Quinn, 1979: 42 , figs 68–74. Solariella lubrica: Springer & Bullis, 1956: 25 ; Lopes & Cardoso, 1958: 62; Rios, 1975: 21, pl. 4, fig. 46; Rios, 1985: 23, pl. 10,

fig. 96; Rios, 1994: 36, fig. 109; Gracia et al., 2004: 50, fig. 17; Miyaji, 2004: 78; Benkendorfer & Soares-Gomes, 2009:

150; Rios, 2009: 56, text fig.; Rosenberg et al., 2009: 623; Barros, 2010: 62, figs 22–28; Miloslavich et al., 2010: table S6;

Welch, 2010: table S1; Daccaret & Bossio, 2011: 54, fig. 91. Suavotrochus lubricus: Bouchet, 2015 .

Type material. Lectotype: USNM 95061 .

Type locality. Cuba, North of Havana, Blake sta. 2, 23º14’N, 82º25’W, 1472 m (24/v/1893) .

Distribution. From Florida Straits to southernmost Brazil, 73–1472 m ( Rosenberg et al. 2009). Quinn (1979), however, remarked that the species might actually inhabit only depths up to 500 m, being carried post-mortem to greater depths. Barros (2010) gave a bathymetric range of up to 5633 m of depth based on empty shells.

Habitat. Muddy bottoms ( Barros et al., 2008)

Material examined. Brazil: Espírito Santo: off São Mateus, continental slope of Abrolhos, 18°59’S, 37°50’W, MD55 sta. DC 75, 295 m, MNHN, 100 sh (27/v/1987). Rio de Janeiro: East of Cabo de São Tomé, 21°31’S, 40°08’W, MD55 sta. CB96, 295– 300 m, MNHN, 1 sh (31/v/1987); S of Cabo Frio, 23°41’S, 42°06’W, MD55 sta. CB104, 430– 450 m, MNHN, 50 sh (02/vi/1987). Additional non-MD55 material: Cuba: lectotype.

Measurements. 5½–6 whorls, H=5.0– 5.5 mm, D=4.0– 4.5 mm (n=20).

Remarks. This species is by far the most abundant trochoid found in the MD55 material. The present specimens compare very well with the lectotype, even though they show an overall less-pronounced sculpture; this is in line with the known degree of morphological variation of this species ( Quinn 1979). The variety (subspecies) Margarita lubrica iridae was described by Dall (1889) as a nearly smooth form (lectotype USNM 95063, paralectotype USNM 887343), but was later considered a synonym of S. lubricus by Quinn (1979), who observed several intermediate stages between these two forms.

Interestingly, some specimens from one locality (sta. CB96) have the teleoconch sculptured by regularly spaced well-marked prosocline ribs. Moreover, S. lubricus has some axial corrugations restricted to the periumbilical area ( Fig. 9 J ), but in these specimens the corrugations seem to be expanded, forming complete ribs ( Fig. 9 L ). To the best of our knowledge, this feature has never been reported for this species. In the present specimens, the axial sculpture is of variable strength and there are even completely smooth specimens.

Figures

FIGURE 9. Solariellidae collected by the MD55 expedition. A–C. Solariella carvalhoi MNHN, sta. CB101 (H=6.9 mm, D=7.8 mm). A. apertural view. B. apical view. C. umbilical view. D–G. Solariella quinni MNHN, sta. DC73 (H=4.2 mm, D=4.2 mm). D. apertual view. E. apical view. F. umbilical view. G. SEM, protoconch detail. H–L. Suavotrochus lubricus. H–J. MNHN, sta. DC75, apertural view (H=4.8 mm, D=3.5 mm). I. apical view. J. umbilical view. K. MNHN, sta. DC75, detail of protoconch under SEM. L. MNHN, sta. CB93, juvenile specimen with ribbed sculpture (H=2.2 mm, D=2.1 mm).