Eulimella ejuncida, 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 : 33-34

Eulimella ejuncida new species

Figures 40–47

Diagnosis. Slender shell with protoconch of one whorl with “arc” shaped suture.

Description. Shell small, slender, with acuminate apex; reaching 3.7 mm in length; white. Teleoconch with up to eight whorls of almost rectilinear profile. Suture shallow, rectilinear. Protoconch heterostrophic planispiral, type B with curved with “arc” shaped suture, diameter 229µm to 265µm (mean =244µm, n=14), with around one whorl. Axial sculpture absent, except for microscopic growth lines. Spiral sculpture absent. Aperture ovoid elongate, inner lip slightly projected into parietal region; columella slightly arcuate, with very small columellar fold. Outer lip thin. Not umbilicate.

Dimensions. Holotype with 3.7 mm length / 0.8 mm width (eight teleoconch whorls), protoconch width: 253 µm, angle to shell axis: 100 o.

Type material. Holotype: MZSP 99916 . Paratypes: MZSP 99918 , REVIZEE sta 6662, [5] ; MZSP 99917 , type locality, [4] ; MZSP 99919 , PADCT sta 6553, [3] ; MNHN 24618 , REVIZEE sta 6652, [3] ; MNRJ 15399 , PADCT sta 6553, [2] ; MNRJ 15398 , type locality, [1] .

Type locality. Off São Paulo state, PADCT sta 6631 (25°46' S, 45°28.8' W, 164 m), southeast coast of Brazil .

Etymology. From Latin ejuncidus = slender.

Geographic distribution. Continental slope (164 – 225 m) in southeast (off São Paulo state) and south (off Santa Catarina state) coasts of Brazil .

Remarks. Eulimella ejuncida ( Figs. 40–47 ) is markedly different from the other Eulimella species from Brazil in shell shape, microsculpture and protoconch. It has an elongate and slender shell ( Figs. 40–41 ), whereas in the other species the shells are wider and conical, as in E. smithii (Figs. 1–3), E. rudis (Figs. 11–12, 16), and E. torquata ( Figs. 19, 23 ); subcylindrical, as in E. cylindrata ( Fig. 26 ); or pupoid, as in E. cf calva ( Figs. 33, 37 ). Eulimella ejuncida ( Figs. 40–42 ) has no trace of the spiral belt formed by axial growth threads, which is present in the other species in variable degrees of expression. Also, the protoconch has only one whorl, with a short curved, “arc” shaped suture emerging from the first teleoconch whorl ( Fig. 44 ). The remaining species have a “spiral” shaped suture (Figs. 5, 15, 21, 28, 35) with varying degrees of immersion into the first teleoconch whorls, but always having at least two whorls.

The most similar species from the western Atlantic is Turbonilla melea Dall, 1927 , described from a depth of 584 m off Fernandina, Florida—actually off Georgia, according to Rosenberg (2009). This species was described based on two shells only. It has a similar general shell shape and dimensions, but the original description mentions a protoconch with 2.5 whorls, forming a helicoid spire. In addition, Dall (1927) indicated that T. melea has obsolete, very ill-defined axial ribs. In fact, after examining the syntype we observed an almost smooth shell; the obsolete axial ribs mentioned by Dall (1927) probably led him to allocate it to the genus Turbonilla , which is characterized by this sculpture.

Eulimella polita ( Verrill, 1872) is also similar in the slender teleoconch, but the whorl profile is more convex and the shell is longer, with more teleoconch whorls.

Some species from West Africa have similarly slender shells, such as Eulimella kobelti ( Dautzenberg, 1913) and Eulimella poligyrata Dautzenberg, 1913 ; but these have a “spiral” shaped protoconch suture. Eulimella protofunis Peñas & Rolán, 1999 has a similar protoconch with the “arc” shaped suture, but in this species the whorls are proportionally shorter and the whorl outline is somewhat sinoidal, with a large convexity just above the suture; in E. ejuncida , the whorl outline is almost rectilinear.

Figures

FIGURE 40–47. Eulimella ejuncida n. sp. 40–41, whole shell (length: 3.7 mm); 42–44. protoconch; 45. last whorl; 46–47. detail of sculpture. 40–43, 46–47. holotype MZSP 99916; 44. paratype MNRJ 15398; 45. paratype MNRJ 15399. Scale bars: 40-41. 1 mm; 42-47. 200 µm.

FIGURE 19–25. Eulimella torquata n. sp. 19, 23: whole shells (lengths: 19. 6.0 mm; 23. 5.72 mm); 20: last whorl; 21–22: protoconchs; 24–25: detail of sculpture. 19–21. holotype (MNRJ 13251). 22–25. paratype (MNHN 24588). Scale bars: 19, 23. 1.0 mm; 20. 500 µm; 21–22, 24–25: 100 µm.

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.

FIGURE 33–39. Eulimella cf. calva. 33, 37: whole shells (lengths: 33. 3.32 mm; 37. 3.0 mm); 34: last whorl; 35–36: protoconchs; 38–39: detail of sculpture. Scale bars: 33, 37. 1.0 mm; 34-36, 38-39. 200 µm. 33–35. DOUFPE 5018; 37–39. DOUFPE 5017.