Eulimella cylindrata, Pimenta & Santos & Absalão, 2011

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 : 30

Eulimella cylindrata new species

Figures 26–31

Diagnosis. Eulimella species with a large and inflated teleoconch, whose whorls decrease in width increment from third whorl on, resulting in an acuminate apex and an almost cylindrical shape from the fourth whorl on; teleoconch whorls with a wide spiral yellow band.

Description. Shell tall, elongate turriform, somewhat inflated, with pointed apex and abrupt decrease in width increment from third teleoconch whorl on, becoming almost cylindrical; reaching 5.3 mm in length; glossy white, some shells with a wide spiral yellow band on each teleoconch whorl, just above suture. Teleoconch with up to eight whorls rectilinear in profile. Suture shallow, rectilinear. Protoconch heterostrophic planispiral, type B with “spiral” shaped suture and ~2.25 whorls; diameter 269µm to 321µm (mean =290µm, n=4). Axial sculpture absent, except for growth lines, more evident as short, microscopic axial threads organized in spiral belts variously located near middle of earlier teleoconch whorls, and not visible in last whorls. Spiral sculpture absent. Aperture ovoid to subquadrate, inner lip barely projected into parietal region; columella arcuate, without columellar fold. Outer lip thin. Not umbilicate.

Dimensions. Holotype with 4.7 mm length / 1.2 mm (7.5 whorls); protoconch width: 297 µm, angle to shell axis: 120 o.

Type material. Holotype: MNHN 24590 , MD 55 sta CB96; paratypes: MNHN 24591 , MD55 sta CB96 [2]; MNRJ 19486 , MD55 sta CB77 [1]; MZSP 101568 , MD55 sta CB96 [1]; IBUFRJ 19202 , off Camburi beach, Espírito Santo state (60 m), 07/v/1986, Eq. Zoo coll.

Type locality. MD 55 sta CB96: 21º31.8’S, 40º08.7’W (295–300 m), east of Cabo de São Tomé , off southeastern Brazil.

Etymology. From Latin cylindrata = in the form of a cylinder. An allusion to the subcylindrical shell shape.

Geographic distribution. Off southeast coast of Brazil.

Remarks. Eulimella cylindrata ( Figs. 26–31 ) is a large species, with a few records on the southeast coast of Brazil. The species is easily recognizable by its tall and somewhat inflated shell. The general shape of the shell is quite different from all other Eulimella species from Brazil, which are conical ( E. smithii , E. rudis , E. torquata , and E. ejuncida ) or pupoid ( E. cf. calva ). In E. smithii , E. rudis , and E. torquata , there is a regular increase in the width of teleoconch whorls, resulting in a strictly conical shell. In E. cylindrata , the width of the teleoconch whorls tends to increase more gradually from the third or fourth whorl on, resulting in a shell with an acute apex (first three teleoconch whorls) and an almost cylindrical shape in the remaining teleoconch ( Figs. 26, 29 ).

The most similar species from the western Atlantic is Eulimella lissa ( Verrill, 1884) ( Fig. 32 ), which also has a somewhat inflated shell and a very similar aperture and columella. However, the width increase is more regular, not resulting in a cylindrical teleoconch as in E. cylindrata . In addition, the whorl profile of E. lissa ( Fig. 32 ) is convex in outline, whereas in E. cylindrata it is more rectilinear.

Eulimella variabilis de Folin, 1870 and Eulimella similminuta Peñas & Rolán, 1997 , both from West Africa, have a similar subcylindrical shell shape. Eulimella variabilis has a very acuminate apex, and E. similminuta shows a very immersed protoconch. Both cases differ from E. cylindrata , whose protoconch is well visible above the first teleoconch whorl ( Fig. 28 ).

The yellow spiral band on teleoconch whorls in a similar pattern to E. smithii , but in E. cylindrata , the spiral band is wider ( Fig. 26 ).

Figures

FIGURE 32. Eulimella lissa Verrill, 1884. Syntype USNM 35433 (length: 4.1 mm). Scale bar: 1 mm.

FIGURE 26–31. Eulimella cylindrata n. sp. 26, 29. whole shell (lengths: 26. 5.3 mm; 29. 5.3 mm); 27. last whorl; 28. protoconch; 30–31. detail of sculpture. 26. holotype (MNHN 24590); 27-29. paratype (MNHN 24591). Scale bars: 26, 29. 1.0 mm; 27. 500 µm; 28, 30–31: 100 µm.