Eulimella rudis Watson, 1886

Pimenta, Alexandre Dias, Santos, Franklin Noel Dos & Absalão, Ricardo Silva, 2011, Taxonomic revision of the genus Eulimella (Gastropoda, Pyramidellidae) from Brazil, with description of three new species, Zootaxa 3063 (1), pp. 22-38 : 27-28

Eulimella rudis Watson, 1886

Figures 11–18

Eulimella rudis Watson (1886) : 496, pl. 33, fig. 2a–c; Lange de Morretes (1949): 84; Rios (1975): 143, fig. 666, pl. 43; (1985): 163, pl. 54, fig. 770; (1994): 185, pl. 61, fig. 859.

Types and type locality. Holotype NHMUK 1887.2 .9.1563. Challenger sta 122 (9°05'S, 34°50'W, 630 m), off Pernambuco, northeast Brazil.

Material examined. The holotype photo and: Brazil: MNHN, MD 55 sta SY74, [1]; MNRJ 16295 , MD 55 sta CB76, [5]; MNHN, MD 55 sta CB76, [2]; MNHN, MD 55 sta DC73, [18]; MNHN, MD 55 sta DC73, [4]; MZSP 101566 , MD 55 sta CB93, [2]; MNHN, MD 55 sta CB93, [7]; MNHN, MD 55 sta CB105, [11]; MNHN, MD 55 sta DC72, [2].

Characterization. Shell tall, with elongate turriform shape, reaching 7.0 mm in length; glossy white. Teleoconch with up to 11 whorls with shallow constriction at middle. Suture shallow, rectilinear. Protoconch heterostrophic planispiral, type B with “spiral” shaped suture and ~2.25 whorls; diameter 231µm to 282µm (mean = 254µm, n=20). Axial sculpture absent, except for growth lines, more evident in last whorls, as short microscopic axial threads organized in a spiral belt in middle of whorl, giving rise to an apparent tiny spiral groove in low magnification. Spiral sculpture absent. Aperture ovoid to subquadrate, inner lip slightly projected into parietal region; columella slightly arcuate, without columellar fold. Outer lip thin. Not umbilicate.

Dimensions. Maximum shell length / width: 7.0 mm / 1.44 mm (eleven teleoconch whorls); maximum protoconch width: 282 µm.

Geographic distribution: Northeastern (~ 9°S, 630 m) and southern (~19 o S to ~24 o S, 610 m to 1,050 m) coast of Brazil .

Remarks. Eulimella rudis Watson, 1886 was originally described from the deep sea off the state of Pernambuco in northeastern Brazil. The few subsequent references to this species are in the molluscan catalogues of Lange de Morretes (1949) and Rios (1970, 1975, 1985, 1994, 2009). These works did not present new material, but merely repeated the occurrence of the species, in some case reproducing the original figure.

Other records of E. rudis were based on misidentifications. Castellanos (1982) recorded E. rudis from Argentina, but illustrated a shell with a totally different shape, much more slender and almost cylindrical. Barros & Oliveira (1996) recorded the species from the Pernambuco coast, but the figures show a shell that does not correspond to E. rudis , being somewhat pupoid in shape, more similar to Eulimella cf. calva (discussed below).

Therefore, this work presents the first confirmed new records of this species after its original description. Although these records are from a latitude (~19 o S to ~24 o S, southeast coast of Brazil) somewhat distant from the original record (~ 9°S, northeast coast of Brazil), such a range is rather common for Brazilian benthic molluscan fauna, and the bathymetry is the same.

The photograph of the syntype of Eulimella rudis (Fig. 11) shows a shell with the same shape as the shells determined herein. Although it is not visible in the photograph, the original figure by Watson (1886) shows the tiny spiral striae in the middle region of the teleoconch whorls, typical of the shells from southeast Brazil illustrated herein (Figs. 12–13, 16–18). The columella is curved in the same way, lacking a fold.

FIGURE 11–18. Eulimella rudis . 11–12, 16. whole shells (lengths: 11. 4.8 mm; 12. 6.3 mm; 16. 6.3 mm); 13. last whorl; 14– 15. protoconchs; 17–18. detail of sculpture. 11. Holotype (NHMUK 1887.2.9.1563); 12–18 (MNHN). Scale bars: 11-12, 16. 1.0mm; 13-15, 17-18. 200 µm.

Eulimella rudis is very similar to Eulimella smithi in dimensions and general shell shape, although E. smithii is more regularly conical, with a straight whorl profile (Figs. 8–9), while E. rudis has a somewhat sinuous whorl profile due to the spiral striae in the middle of the whorls (Figs. 13, 17–18). Furthermore, Eulimella rudis is always white, without any trace of the spiral color band; Eulimella rudis has a curved columella (Figs. 11–13, 16), but lacks the fold present in E. smithii (Fig. 4). The spiral belt formed by the axial threads is stronger in E. rudis (Figs. 17–18) and readily visible in all shells; whereas in E. smithii these threads are weaker (Figs. 8–9) and tend to disappear in some shells.