Eulimastoma Bartsch, 1916

Pimenta, Alexandre D. & Absalão, Ricardo S., 2004, Review of the genera Eulimastoma Bartsch, 1916 and Egila Dall & Bartsch, 1904 (Mollusca, Gastropoda, Pyramidellidae) from Brazil, Zoosystema 26 (2), pp. 157-173 : 159-161

Genus Eulimastoma Bartsch, 1916

Odostomia (Eulimastoma) Bartsch, 1916: 73 .

TYPE SPECIES. — Odostomia (Scalenostoma) dotella Dall & Bartsch, 1909 by original designation.

DIAGNOSIS. — Shell small, elongate-conic, smooth or with microscopic spiral striae on the base; protoconch heterostrophic generally with immersed nucleus; teleoconch whorls flattened; suture V-shaped notched, with or without suprasutural spiral cord; with or without columellar fold; umbilicus variable, from absent to a deep one.

REMARKS

Eulimastoma was employed at full generic level by Bartsch (1955), Altena (1975), Odé & Speers (1972), Odé (1994) and Rios (1994). For discussion on nomenclature and synonymy, see Odé (1994).

According to Odé & Speers (1972), this genus, although well defined as a group, includes several species that display a great range of variation in shell morphology. The main diagnostic characters of this genus are the immersed protoconch and the V-shaped suture ( Odé & Speers 1972; Odé 1994). Also, a spiral cord above the Vshaped suture can be seen from the third or fourth whorl onward and is very conspicuous in the type species Eulimastoma dotella ( Dall & Bartsch, 1909) ( Dall & Bartsch 1909: pl. 30, fig. 5).

The genus Eulimastoma has not being used in recent reviews of European pyramidellids. However, some species included in other genera, such as Odostomia (Megastomia) pagodiformis Schander, 1994 ( Schander 1994: fig. 6b) and Odostomia (Pyramistomia) fehrae Van Aartsen, Gittenberger & Goud, 1998 ( Van Aartsen et al. 1998: fig. 40) are similar to the concept of Eulimastoma herein used and further studies comparing the faunas from the two sides of the Atlantic Ocean are necessary to better clarify the classification of the species in the Pyramidellidae . Beside the species herein reported from Brazil, additional species from Western Atlantic coast have been, elsewhere, referred to Eulimastoma . We give a brief summary of them:

1. Odostomia (Evalea) pocahontasae Henderson & Bartsch, 1914 ( Henderson & Bartsch 1914: 418, pl. 13, fig. 6), described from Chincoteague Bay, Virginia, USA. This species was reported from the Gulf of Mexico by Odé (1994) who considered that it is probably an adaptation of Eulimastoma canaliculatum to its environment. The figure provided by Henderson & Bartsch (1914) resembles E. canaliculatum indeed.

2. Eulimastoma harbisonae Bartsch, 1955 ( Bartsch 1955: 82, pl. 16, fig. 1) and Eulimastoma olssoni Bartsch, 1955 ( Bartsch 1955: 83, pl. 16, fig. 5), both described from Pliocene of North St Petersburg, Florida, USA. Odé (1994) reported E. harbisonae from Texas coastal bays and stated that it produces specimens with open and with closed umbilicus, suggesting the synonym with E. olssoni .

3. Pyramidella (Sulcorinella) bartschi Winkley, 1909 ( Winkley 1909: 39, fig. 1), described from Woods Hole, Massachussets, USA. Odé (1994) reported specimens from Texas as Eulimastoma cf. bartschi . However, as demonstrated by Robertson (1996) based on anatomy, reproductive characters and host preferences, this species is better included in the genus Fargoa , a genus that encloses both high sculptured shells and nearly smooth ones due to evolutionary divergence in shell sculpture ( Robertson 1996).

4. Orinella ? (Cricolophus) humboldti Weisbord, 1962 ( Weisbord 1962: 460, pl. 43, figs 15, 16). Holotype PRI 26351, Pliocene of La Salina, Carabobo ( Venezuela). This species has been reported from Yucatan Peninsula, Mexico ( Vokes & Vokes 1983) and Brazil ( Rios 1994), in the genus Eulimastoma . See discussion under Eulimastoma didyma .

Eulimastoma canaliculatum (C. B. Adams, 1850) ( Fig. 1 )

Odostomia canaliculata C. B. Adams, 1850: 109 . — Clench & Turner 1950: 262, pl. 40, fig. 3. — Jong & Coomans 1988: 121.

Eulimastoma canaliculatum – Altena 1975: 70, fig. 26a, b.

Eulimastoma canaliculata – Odé & Speers 1972: 14, fig. 12. — Odé 1994: 21, figs 5-7.

Odostomia (Odostomia) canaliculata – Vokes & Vokes 1983: 32, pl. 30, fig. 1. — Mello & Perrier 1986: 138. — Díaz & Puyana 1994: 233, pl. 69, fig. 625. — Rios 1975: 142, pl. 43, fig. 656; 1985: 163, pl. 54, fig. 771; 1994: 185, pl. 61, fig. 860.

Odostomia (Evalea) canaliculata – Mello 1990: 40, fig. 7.

TYPE MATERIAL. — Holotype ( MCZ 186101 ).

TYPE LOCALITY. — Jamaica.

OTHER MATERIAL EXAMINED. — Brazil. Amapá State, AMASSEDS, RV Columbus Iseling , stn 3221, 03°23.08’N, 50°04.08’W, 40 m, 15.V.1990, 4 specs ( IBUFRJ 4180). — Pará State, AMASSEDS, RV Columbus Iseling , stn 3210, 01°52.45’N, 48°16.02’W, 47 m, 12.V.1990, 6 specs ( IBUFRJ 4147). — Pernambuco State, Itamaracá, Praia de Jaguaribe, 1 spec. ( MNHN); Recife, Praia do Pina, 5 specs ( MNHN); Cabo, Praia de Gaibu, 2 specs ( MNHN); Paulista, Praia de Maria Farinha, 9 specs ( MNHN); Cabo (pedras pretas), 2 specs ( MNHN); Paulista, Praia de Maria Farinha, 2 specs ( MNHN); Paulista, Praia da Conceição, 1 spec. ( MNHN). — Maranhão State, São Luiz, Praia de Areia Preta, 1 spec. ( MNHN). — Bahia State, Itaparica, Praia do Despacho, 2 specs ( MNHN). — Rio de Janeiro State, Arquipélago de Santana, Macaé, Astro Garoupa, V.1993, 5 specs ( IBUFRJ 9623); Enseada de Dois Rios, Ilha Grande, stn 6, 1996, 11 specs ( UERJ 1971).

Material of Eulimastoma cf. canaliculatum : Pernambuco State, Praia de Raposa, 3 specs ( MNHN). — Bahia State, Itaparica, Praia do Despacho, 10 specs ( MNHN).

DISTRIBUTION. — USA (Texas); Jamaica; Mexico (Yucatan Peninsula; NW Gulf of Mexico); Colombian Caribbean; West Indies ( Aruba, Bonaire and Curaçao Islands); Suriname; N, NE and SE coasts of Brazil (Amapá, Pará, Pernambuco, Maranhão, Bahia and Rio de Janeiro states).

DESCRIPTION

Shell white, conical with slightly convex whorls. Holotype 3.2 mm in length; 1.14 mm in width. Protoconch intorted, sunken into first teleoconch whorl. Sutures oblique to shell main axis, almost straight, somewhat channeled, without adjacent spiral cords. Axial and spiral sculpture absent. Base rounded, smooth with a very distinct small chink-like umbilicus. Aperture rhomboid. Outer lip thin. Columellar fold very prominent.

REMARKS

The original description of E. canaliculatum does not mention the umbilicus which is very conspicuous in the holotype ( Fig. 1A ) and in Brazilian specimens ( Fig. 1 B-E). This species exhibits some degree of variation in the spire angle of the shell and in the convexity of the whorls ( Fig. 1 A-D). Besides that, 13 Brazilian specimens from some localities in Bahia and Pernambuco states, herein called E. cf. canaliculata , are very similar to typical

Eulimastoma and Egila (Mollusca, Gastropoda ) from Brazil specimens of E. canaliculatum and probably the same species, with the same type of protoconch, teleoconch shape, sculpture and identical umbilicus, but lacking the columellar fold ( Fig. 1D ). Considering the co-occurence of these specimens and typical E. canaliculatum ( Fig. 1B, C ) and the fact that Eulimastoma species display a wide range of intraspecific variation in shell morphology ( Odé & Speers 1972; Odé 1994), we feel not secure to treat them as a different species. As will be seen for E. engonium , the expression of the columellar fold is a variable character in the species.

Figures

FIG. 1. — Eulimastoma canaliculatum (C. B. Adams, 1850); A, holotype (MCZ 186101), length 3.20 mm; B-F, Brazilian specimens (all from off Pernambuco State, MNHN); B, C, whole shells, respective lengths: 2.56 mm, 2.60 mm; D, whole shell of E. cf. canaliculatum, length 2.52 mm; E, aperture; F, protoconch of E. cf. canaliculatum. Scale bars: 100 µm.