Eulimastoma engonium ( Bush, 1885 )

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 : 161-169

Eulimastoma engonium ( Bush, 1885)

( Fig. 2 )

Odostomia engonium Bush, 1885: 466 . — Abbott 1974: 292. — Johnson 1989: 36, pl. 16, fig. 1.

Odostomia engonium var. teres Bush, 1885: 467 , pl. 45, fig. 9. — Johnson 1989: 69.

Eulimastoma engonium – Odé & Speers 1972: 13, fig. 10. — Odé 1994: 21, fig. 4.

Eulimastoma teres – Odé & Speers 1972: 13, figs 8, 9. — Lyons 1989: 29, pl. 12, fig. 4. — Odé 1994: fig. 3. Odostomia teres – Jong & Coomans 1988: 122, pl. 6, fig. 641a. — Abbott 1974: 292.

Eulimastoma engonia – Lyons 1989: 29, pl. 12, fig. 3.

Eulimastoma weberi – Absalão et al. 1996: 66, fig. 10.

TYPE MATERIAL. — Lectotype (herein designated): Beaufort, North Carolina ( YPM 16145); paralectotypes: Vicinity of Cape Hatteras, North Carolina, 2 specs ( YPM 16146, 16148 ); off Cape Hatteras , North Carolina, 3 specs ( YPM 16147); 1 spec. ( USNM 44762 ); syntypes of E. engonium var. teres: Vicinity of Cape Hatteras, North Carolina, 9 specs ( YPM 16149, 16152 , 16153 , 16154 ); off Cape Hatteras, North Carolina, 5 specs ( YPM 16150, USNM 44951 ).

TYPE LOCALITY. — Off Cape Hatteras, 27-28.8 m and Beaufort, North Carolina.

MATERIAL EXAMINED. — The type material from YPM and the following specimens:

Brazil. Pará State, off Pará, 40-70 m, 2 specs ( IBUFRJ 6024 ). — Maranhão state, São Luiz , Praia de Areia Preta , 6 specs ( MNHN). — Bahia State, Itaparica , Praia do Despacho , 1 spec. ( MNHN). — Espírito Santo State, off Aracruz , 1 spec. ( IBUFRJ 8996 ). — Rio de Janeiro State, GEOMAR XII, stn 10, 1 spec. ( IBUFRJ 7780 ) ; Arquipélago de Santana, Macaé, V.1993, Astro Garoupa , 11 specs ( IBUFRJ 9622 ), 15 specs ( IBUFRJ 9621 ) ; GEOMAR XII, stn 112, 1 spec. ( IBUFRJ 7812 ) .

DISTRIBUTION. — USA (North Carolina, Texas) ; Mexico (NE Gulf of Mexico) ; West Indies ( Aruba Island) ; N, NE and SE coasts of Brazil (Pará, Maranhão, Bahia, Espírito Santo and Rio de Janeiro states) .

DESCRIPTION

Shell white, conical-elongate with rectilinear whorls. Lectotype (here designated) 6.1 mm in length; 2.1 mm in width. Protoconch intorted, sunken into first teleoconch whorl. Sutures oblique, almost straight, channeled, with adjacent posterior spiral cord. Axial sculpture absent but spiral sculpture present on the base. Suture deep, bordered by a rounded suprasutural spiral cord. Base rounded, with fine spiral stria; with a distinct but small chink-like umbilicus somewhat variable in development. Aperture rhomboid. Outer lip thin. Columellar fold usually inconspicuous.

REMARKS

Johnson (1989) listed holotypes (in USNM) and paratypes (in YPM) for both Eulimastoma engonium and E. engonium var. teres , probably based on the fact that the specimens from USNM had been measured ( E. engonium ) or illustrated ( E. teres ) in the original publication. However, the original publication of these two species by Bush (1885) does not mention holotypes, paratypes, “the type” or other equivalent expression refering to the type series used to describe the species; actually, both descriptions were based on more than one specimen. In this case, the inference of a holotype made by Johnson (1989) cannot be considered a lectotype designation by inference of holotype ( ICZN 1999), since Johnson knew that there was more than one specimen in the type series. The International Code of Zoological Nomenclature ( ICZN 1999: Article 74.6) states that fixation of lectotype by inference of “ holotype ” before 2000 requires that the author that makes such inference assumes that the species-group taxon was based upon a single specimen.

We examined the four lots labeled as syntypes of E. engonium in YPM. From these, we designate the shell in lot YPM 16145 ( Fig. 2A, B ) as lectotype of E. engonium . This designation is made to establish the type status of the specimens in the type series, since there are confusion regarding their type status following Johnson (1989). The selection of the YPM 16145 specimen is based on its good condition, locality, for being from a collection that bears several other syntypes of this species, according to the recommendation of Article 74.7 of the Code ( ICZN 1999). This specimen is referred to in Bush’s original remarks as: “A more mature specimen from Beaufort, N.C., is 6.5 mm long; 2.8 mm broad”; we measured this specimen, founding 6.1 mm in length and 2.1 in width; the difference in the measurements can be probably explained assuming that Bush calculated the measurements using a microscope equipped with a camera lucida and overlooks the additional magnification produced by that instrument ( Absalão & Pimenta 1999).

Also, the YPM collection bears six lots (15 specimens, not 13 as reported by Altena [1975]) labeled as syntypes for Eulimastoma engonium var. teres . From these, one shell ( YPM 16151) is not Eulimastoma , but Chrysallida , as noticed by Altena (1975) and another one (one shell out four of YPM 16154) has a very distinct tooth on the columella and is more likely Eulimastoma canaliculatum . The remaining 13 have no collumelar tooth, are slender, fitting very well in the description by Bush (1885). We figure two of them ( Fig. 2 D-F).

According to Odé (1994), Eulimastoma engonium can be distinguished from E. teres by its larger shells, with an apical angle wider, a less deep suture, a more diamond shaped aperture and by the presence of an obsolete columellar fold, while E. teres is more slender and has no columellar fold, even an obsolete one. In spite of these differences, Odé (1994) states that the Eulimastoma engonium is rather variable with respect to the depth of the suture, size and slenderness.

There is some variation in the degree of expression of the columellar fold as well. As reported by Altena (1975), from the six shells labeled as syntypes of E. engonium in YPM, three of them (lots 16145, 16146, 16148) have an indistinct (obsolete) fold on the columella, while two of them ( YPM 16147) have no tooth; in fact, these two shells to which Altena refers and a third one from the same lot, which is glued by its aperture in a paper card (and so the aperture is invisible), are more slender than typical E. engonium , being more similar to E. engoniun var. teres (an observation also written on the label of this lot). We follow the Article 57.7 ( ICZN 1999), “precedence of names of species over those of subspecies”, to synonymize E. engonium over E. engonium var. teres .

The Brazilian shells herein identified as E. engonium ( Fig. 2 G-J) are very similar to the type specimens of this species and of E. engonium var. teres ( Fig. 2 D-F), except for the columellar fold, which is somewhat visible in the type specimens and is very distinct in the Brazilian specimens. Moreover, the Brazilian specimens show a variation in the expression of the umbilicus; some specimens have a chink-like umbilicus, whereas others are imperforate ( Fig. 2I ). On the other hand all the type specimens have a chink-like umbilicus ( Fig. 2 A-E).

The large range of variation in Eulimastoma species had already been observed by Odé & Speers (1972) when they stated that all species appear to be highly variable in shell morphology; in the same population one can find umbilicate and imperforate shells, specimens with keeled or rounded periphery, and shells with a strongly notched or shallow suture. Thus, we do not consider the variation in the size of the shell, width of the whorls, depth of the suture, expression of the columellar fold and umbilicus as characters that can be used to distinguish between E. engonium and its variety teres .

Absalão et al. (1996) identified shells of E. engonium as Eulimastoma weberi Morrison, 1965 , based on the similarity of their material to the specimen determined by Altena (1975: fig. 28) (which is also imperforate and has a well developed columellar fold). However, Altena (1975) expressed doubts about the accuracy of his identification of E. weberi , since, as he reported, the holotype ( USNM 635638) and paratypes of E. weberi do not show any trace of columellar fold. Moreover, the holotype of E. weberi ( Fig. 4A, B ) shows two spiral keels, one above the suture, the other below it, in a pattern similar to E. didyma . The shells illustrated by Altena (1975) as E. weberi and E. engonium lack the keel below the suture.

Eulimastoma surinamense Altena, 1975 ( Fig. 3 )

Eulimastoma engonium surinamense Altena, 1975: 70 , fig. 27. — Rios 1994: 187, pl. 61, fig. 870. — Barros 1994a: 69, fig. 12b.

Odostomia (Eulimastoma) engonium surinamense – Mello 1990: 42, fig. 19. — Díaz & Puyana 1994: 236, pl. 69, fig. 940.

TYPE MATERIAL. — Holotype and 33 paratypes (Rijksmuseum van Natuurlijke Historie, Leiden).

TYPE LOCALITY. — Near Popogaimama Creek, Saramacca District, Surinam.

MATERIAL EXAMINED. — Maranhão State, São Luiz, Praia de Areia Preta, 2 specs ( MNHN). — Pernambuco State, Cabo , Laguna de Suape , 1 spec. ( MNHN) ; Praia de Raposa , 4 specs ( MNHN) . —

Eulimastoma and Egila (Mollusca, Gastropoda) from Brazil

Bahia State, off Caravelas , IX.1985, R. Noveli coll., 2 specs ( IBUFRJ 5993 ) ; Itaparica, Praia do Despacho, 1 spec. ( MNHN). — Espírito Santo State, REVIZEE, stn C63, 19°40’42”S, 038°08’15”W, 61 m, NOAN, 25.IV.1996, 1 spec. ( IBUFRJ 12675 ). — Rio de Janeiro State, Arquipélago de Santana , Macaé , Astro Garoupa , V.1993, 3 specs ( IBUFRJ 6372 ) .

DISTRIBUTION. — Colombian Caribbean; Surinam (Saramacca District) ; N, NE and SE coasts of Brazil (Maranhão, Pernambuco, Bahia, Espírito Santo and Rio de Janeiro states) .

DESCRIPTION

Shell white, elongate-conic with rectilinear to slighty convex whorls with anterior periphery strongly angulated. Holotype 3.2 mm in length; 1.1 mm in width. Protoconch intorted, partially sunken into first teleoconch whorl. Sutures deep, oblique, slightly sinuous; with two rounded suprasutural spiral cords. Usually the suprasutural spiral cord immediately above the suture is narrower. Minute axial ridges present between the suprasutural spiral cords and below the narrower one, sometimes extending to the upper part of the base as evanescent scars. These suprasutural cords are more visible toward the latter whorls. Base rounded, smooth (except by obsolete axials posteriorly); usually imperforate but a barely-discernible chink-like umbilicus may be present. Aperture rhomboid. Outer lip thin. Columellar fold absent.

REMARKS

Eulimastoma surinamense ( Fig. 3 ) was described as a variety of E. engonium but despite the same shell profile, the conchological differences are enough to give it a full species status. Especially relevant are the two suprasutural spiral cords and the axial ridges in sutural region ( Fig. 3C, D ).

Eulimastoma didyma ( Verrill & Bush, 1900) ( Fig. 4 A-I)

Odostomia (Cyclodostomia) didyma Verrill & Bush,

1900: 533, pl. 45, fig. 14. — Odé & Speers 1972: 13.

— Johnson 1989: 34. — Díaz & Puyana 1994: 233,

69, fig. 926. — Wise 1996: 492, 493, fig. 14a-g.

Cyclodostomia didyma – Odé 1993b: 56.

Odostomia didyma – Jong & Coomans 1988: 122, pl. 19, fig. 641. — Redfern 2001: 142, pl. 64, fig. 586A-C.

Eulimastoma humboldti – Rios 1994: 187, pl. 61, fig. 871.

TYPE MATERIAL. — Holotype ( YPM 15706).

TYPE LOCALITY. — Bermuda.

OTHER MATERIAL EXAMINED. — West Indies. Aruba, I. Peeters coll., 14 specs ( ZMA) ; Curaçao, Santa Marta , 30 m, de Jong leg., 50+ specs ( ZMA) ; W Tiara Beach Hotel, Cayman Brac , 10.IV.1991, M. J. Faber leg., 3 specs ( ZMA) ; Curaçao, de Jong coll., 4 specs ( ZMA) .

Brazil. Amapá State, AMASSEDS, RV Columbus Iseling , stn 3228, 03°25.13’N, 49°54.76’W, 74 m, 17.V.1990, 3 specs ( IBUFRJ 6534 ). — Pernambuco State, Recife, Praia do Pina , 2 specs ( MNHN) ; Praia de Raposa, 1 spec. ( MNHN) ; Paulista, Praia de Maria Farinha , 2 specs ( MNHN) ; Recife, Praia do Pina , 1 spec. ( MNHN) ; Praia de Raposa, 1 spec. ( MNHN). — Bahia State, Itaparica, Praia do Despacho , 4 specs ( MNHN). — Rio de Janeiro State, GEOMAR XII, stn 11, 1 spec. ( IBUFRJ 6970 ) ; Enseada de Dois Rios, Ilha Grande , stn 3, 1996, 1 spec. ( UERJ 1972 ) .

Material of Eulimastoma aff. didyma: Enseada de Dois Rios , Ilha Grande, RJ, stn 6, 1996, 4 specs ( UERJ 1973).

DISTRIBUTION. — USA (Texas); Bermuda; Bahamas Islands (Abaco Island); Colombian Caribbean; West Indies ( Aruba and Curaçao Islands); Mexico (NW Gulf of Mexico); N, NE and SE coasts of Brazil (Amapá, Pernambuco, Bahia, and Rio de Janeiro states).

DESCRIPTION

Shell white, conical with rectilinear whorls. Holotype 1.78 mm in length. Protoconch intorted, sunken into first teleoconch whorl. Axial and spiral sculpture absent except at suture. Suture almost straight, deep, somewhat channeled, surrounded by a suprasutural spiral cord and a less conspicuous subsutural spiral one. Base rounded, varying from smooth to spirally striated, with its anterior periphery marked by a deep furrow below the spiral cord of the preceding whorl and bordered anteriorly by another spiral cord; with a very distinct small chink-like umbilicus variably developed. Aperture rhomboid. Outer lip thin. Columellar fold very prominent.

REMARKS

Eulimastoma didyma was included in the genus Cyclodostomia by Verrill & Bush (1900) and Odé (1993b). However, as demonstrated by Van Aartsen & Corgan (1999), Cyclodostomia should be considered monotypic, including only its type species, Odontostomia (Cyclodostomia) mutinensis Sacco, 1892 , renamed Odostomia italiana by Corgan & Van Aartsen (1998).

Eulimastoma didyma has some degree of variation in the expression of the upper spiral cord ( Fig. 4 B-D). In addition, Jong & Coomans (1988) and Díaz & Puyana (1994) illustrated specimens with spiral cords on the base. Despite the eroded state of the holotype of this species ( Fig. 4A ), the original description and illustration do not show this sculpture. Jong & Coomans (1988) consider this species to bear two “forms”, depending on the expression of the “cingula” and groove on the periphery of the base. Indeed, we could see a large variation in the specimens studied regarding the expression of the cords, the periphery of last whorl, on the upper spiral cord and on the striation of the base ( Fig. 4 E-G).

Vokes & Vokes (1983) and Rios (1994) reported Eulimastoma humboldti ( Weisbord, 1962) from Peninsula of Yucatan ( Mexico) and northeast Brazil, respectively. This is a fossil species from the Pliocene of La Salina, Carabobo ( Venezuela), originally described as Orinella ? (Cricolophus) humboldti . The material studied by Vokes & Vokes (1983) could not be found, but we examined the specimens upon which Rios (1994) based his record from Brazil, from the locality of Pina, Pernambuco State, and noticed that the shells belong to E. didyma , with spiral cords along the entire surface of the base ( Fig. 4D, G, H ). Actually the original figure of E. humboldti resembles E. dydima , what led to the record by Rios (1994) and probably that of Vokes & Vokes (1983). Examination of the holotype of E. humboldti ( PRI 26351) ( Fig. 4L ) revealed a shell with the last whorl, base and aperture broken; the remaining parts of the shell, however, are very similar to E. dydima , with a little smaller protoconch. Due to the similarity between the shells from Brazil and holotype of E. didyma and speci-

Pimenta A. D. & Absalão R. S.

mens of this species from West Indies, and also considering that this is a recent taxon, contrary to the Pliocene fossil E. humboldti , we use the specific name E. didyma to refer to Brazilian specimens. Although Grant & Gale (1931), working with Pyramidellidae , stated that “perhaps none of the Pleistocene species is extinct” and lists several species of Turbonilla occuring from Pleistocene to Recent and few species from Pliocene to Recent, we prefer to keep Eulimastoma humboldti as a valid species, based on the lack of additional specimens from type locality for study and to the geological time separating both taxa.

Some shells collected in Rio de Janeiro State ( Fig. 4J, K ) have the same shell shape and sculpture of E. didyma , including the double spiral cords in the periphery of the base ( Fig. 4J ). However, these examples have a different protoconch, with its axis oriented about 90° in relation to teleoconch axis ( Fig. 4K ). As we are not sure about the exact taxonomic significance of this character, we prefer to simply designate them Eulimastoma aff. didyma .

Eulimastoma aff. weberi ( Morrison, 1965) ( Fig. 5 C-G)

Odostomia weberi Morrison, 1965: 221 , fig. 3.

MATERIAL EXAMINED. — Brazil. REVIZEE, stn 52C,

21°46’S, 40°05’W, 450 m, 9 specs ( IBUFRJ 12678).

DISTRIBUTION. — USA (Lousiana; Texas); Mexico (NW of Gulf of Mexico); occurence of E. aff. weberi in Brazil (coast of Rio de Janeiro State).

DESCRIPTION

Shell white, conical with rectilinear whorls. Holotype 1.4 mm in length; 0.7 mm in width. Protoconch intorted, partially sunken into first teleoconch whorl. Sutures almost straight, channeled. A supra- and other subsutural rounded keels present, axial sculpture absent. Base round- ed, smooth; no umbilicus. Aperture rhomboid. Outer lip thin. Columellar fold absent.

REMARKS

According to its original description ( Morrison 1965), holotype (USNM 635638, from North of Bayou Chene Fleur, northern part of Barataria Bay, Lousiana) ( Fig. 5A, B ) and as seen in the shell illustrated by Odé & Speers (1972: fig. 7), E. weberi has two spiral cords per whorl, contrary to the definition of Eulimastoma of a suprasutural cord only. For this reason, and in the lack of further clear options, we consider that this species should be only provisionally included in Eulimastoma .

The Brazilian specimens herein identified as Eulimastoma aff. weberi ( Fig. 5 C-G) differ from E. weberi by their less canaliculate suture compared to the holotype and illustrations of E. weberi which has an excavated V-shaped suture. Besides, the subsutural spiral cord in E. weberi is visible from the second teleoconch whorl onward but in E. aff weberi it is only discernible on the body whorl ( Fig. 5 C-E). Odé (1994) reported E. weberi from Gulf of Mexico, with a great variabilty in shape, both in spire angle and development of spiral ridges. Barros (1994a, c) recorded E. weberi from northeast coast of Brazil, but the illustration is lacking or too poor to allow a precise identification. Absalão et al. (1996: fig. 10) and Altena (1975: fig. 28) illustrated specimens of E. engonium misindentified as E. weberi .

Figures

FIG. 2. — Eulimastoma engonium (Bush, 1885); A, B, lectotype here designated (YPM 16145), A, whole shell, length 6.10 mm; B, last whorl; C, pararalectotype (YPM 16146), length 4.95 mm; D-F, syntypes of E. engonium var. teres (Bush, 1885); D, E, YPM 16153; F, YPM 16150; D, F, whole shells, respective lengths: 4.00 mm, 3.08 mm; E, last whorl of syntype of E. engonium var. teres (YPM 16153); G-J, Brazilian specimens; G-I, whole shells, respective lengths: 1.95 mm, 3.73 mm, 2.04 mm; G, H, IBUFRJ 9621; I, MNHN; J, protoconch (MNHN). Scale bars: B, E, 200 µm; J, 100 µm.

FIG. 4. — A, Eulimastoma didyma (Verrill & Bush, 1900), holotype, length 1.78 mm (YPM 15706); B-I, E. didyma, Brazilian material, B, E, UERJ 1973; C, D, F-I, MNHN; B-D, whole shells, respective lengths: 1.70 mm, 1.73 mm, 1.65 mm; E-G, last whorls; H, I, protoconchs; J, K, Eulimastoma aff. didyma (UERJ 1973); J, whole shell, length 1.60 mm; K, protoconch; L, Eulimastoma humboldti (Weisbord, 1962), holotype, length 1.40 mm (PRI 26351). Scale bars: 100 µm.

FIG. 3. — Eulimastoma surinamense Altena, 1975 from Brazil (MNHN); A, B, whole shells, respective lengths: 3.17 mm, 2.95 mm; C, last whorl; D, base of last whorl; E, protoconch. Scale bars: 100 µm.

FIG. 5. — A, B, Eulimastoma weberi (Morrison, 1965), holotype, length 1.40 mm (USNM 635638), courtesy Dr Jerry Harasewych, Yolanda Villacampa (USNM); C-G, Eulimastoma aff. weberi (IBUFRJ 12678); C, D, whole shells, respective lengths: 1.73 mm, 1.26 mm; E, last whorl; F, G, protoconchs. Scale bars: 100 µm.