Trabecula krumpermanni ( Jong & Coomans, 1988 ) Jong & Coomans, 1988

Pimenta, Alexandre Dias, Absalão, Ricardo Silva & Miyaji, Cintia, 2009, A taxonomic review of the genera Boonea, Chrysallida, Parthenina, Ivara, Fargoa, Mumiola, Odostomella and Trabecula (Gastropoda, Pyramidellidae, Odostomiinae) from Brazil, Zootaxa 2049, pp. 39-66 : 61-62

Trabecula krumpermanni ( Jong & Coomans, 1988) comb. nov.

( Figs. 62−65 )

Turbonilla krumpermanni Jong & Coomans, 1988: 131 , pl. 20, 46, fig. 678. Redfern 2001: 150, pl. 67. fig. 627. Salassiella sp.: Lyons 1989: 29, pl. 12, fig. 11.

Odostomia (Salassiella) richi auct non Dall & Bartch, 1909: Mello 1990: 42, fig. 18. Odostomia (Salassiella) laxa auct non Dall & Bartsch, 1909: Mello and Barros 1991: 14, fig. 15. Odostomia (Salassiella) aff. laxa: Rios 1994: 187 , pl. 77, fig. 868a.

Types and type locality: Holotype: ZMA 3.87.110. Curaçao / Aruba, West Indies, K. M. Jong coll ( Fig. 62 ).

Material examined: The holotype and: -- Brazil: --Pernambuco State: MNHN, Cabo (praia de Gaibu) [2]; MNHN, Cabo [3]; MNHN, Recife [3]; MNHN, Cabo (enseada dos corais) [4]; MNRJ 10975, Paulista (Maria Farinha) [2]; MNHN, Itamaracá (praia de Jaguaribe) [1]; MNHN, Recife (praia do Pina) [2]; MNHN, Recife (praia do Pina) [4]; --Bahia State: MNHN, Praia de Rio Vermelho [1]; IBUFRJ 10811, Guarajuba, i/1989, L. Trinchão coll. [2]; MORG 27644, Itapuã, Salvador [1]; MORG 38550, R. Areia, Abrolhos Archipel [1]; -- Espírito Santo State: IBUFRJ 6000, Camburi, 19/iii/1993, eq. Zoo. coll. [1]; IBUFRJ 10311, Aracruz, 01/xii/ 1989, V. Abud coll. [8]; --Rio de Janeiro State: MZSP 86703, off Bacia de Campos [1]; IBUFRJ 10494, off Bacia de Campos (22o15’20”S, 40o19’45”W, 100m), AG coll. [1]; IBUFRJ 8988, off Angra dos Reis, 1997, C. Alvarenga coll. [1].

Remarks: The type species of Trabecula ( Trabecula jeffreysiana Monterosato, 1884 ) has been included in the genera Chrysallida ( Aartsen, 1981; Linden & Eikenboom, 1992) and Odostomella ( Peñas et al. 1996) . Since T. jeffreysiana is the type species of this genus, we presume that these authors considered Trabecula a synonym of Chrysallida or Odostomella , although they did not clearly state this.

Odé (1993b), on the other hand, considered Trabecula as a valid genus and Salassiella Dall & Bartsch, 1909 as a synonym of Trabecula , based on the great similarity between the type species ( Salassiella laxa and Trabecula jeffreysiana , respectively). He further diagnosed Trabecula as having strong axial ribs continuing over the base, with formation of varices, no spiral sculpture and a very weak columellar fold. Odostomella was characterized by Schander (1994) and Peñas et al. (1996) as having strong axial sculpturing and a welldeveloped columellar fold, but lacking spiral sculpture and varices. Therefore, based on the above differences, and following Odé (1993b), we consider Salassiella as synonym of Trabecula , and different from Odostomella .

Mello (1990) recorded Odostomia cf. richi Dall & Bartsch, 1909 or (sic) Odostomia cf. laxa Dall & Bartsch, 1909 , and Mello and Barros (1991) reported Odostomia (Salassiella) laxa from the coast of Pernambuco (northeast Brazil), while Rios (1994) recorded this same taxon as Odostomia (Salassiella) aff. laxa . In fact, Odostomia laxa , which occurs on the coast of California, is very similar to Trabecula krumpermanni and also to Trabecula jeffreysiana Monterosato, 1884 . Robertson (1978) stated that there might be convergence between odostomioid shells from mutually isolated populations (see discussion under Fargoa bushiana ).

Herein, we report the Brazilian specimens ( Figs. 63−65 ) with the western Atlantic name T. krumpermanni (holotype herein illustrated in Fig. 62 ). Redfern (2001) also used this name for shells from the Bahamas, although allocated to its original genus, Turbonilla . The known geographical range of T. krumpermanni is herein considered to be enlarged to southeastern Brazil (≅23o S).

Trabecula krumpermanni ( Figs. 62−65 ) was originally placed by Jong and Coomans (1988) in the genus Turbonilla . However, the species does not fit the concept of this genus, since it has a deeply immersed protoconch ( Fig. 65 ), while members of the genus Turbonilla have prominent protoconchs that project beyond the first teleoconch whorl. Due to its great similarity to the type species of Trabecula , we introduce the new combination Trabecula krumpermanni . Actually, Odé (1993b) has already used the genus Trabecula ; however, Odé (1993b) identified the shells from Texas as Trabecula laxa , a position that we do not support, as discussed above. Odé (1993b) went further and considered the possibility of synonymy between T. laxa and T. jeffreysiana . This hypothesis for a worldwide distribution in a pyramidellid species remains open, to be tested by other sources of data.

Trabecula krumpermani varies widely in the shape of the apex, with variable width of the first whorls. The holotype ( Fig. 62 ) is an example of a more pupoid shape, with a less acuminate apex and larger width in the first three whorls; the figured paratype ( Jong & Coomans 1988: pl. 20, fig. 678) and most of the Brazilian material ( Figs. 63−65 ), as well as the shell illustrated by Redfern (2001: pl. 67. fig. 627), have more acuminate apices.

Figures

FIGURES 62 − 65. Trabecula krumpermanni. 62: holotype (ZMA 3.87.110); 63: (IBUFRJ 10776); 64 − 65: (IBUFRJ 10495). 62 − 64: whole shells (respective lengths: 6.2 mm, 8.6 mm, 5.7 mm); 65. protoconch. Scale bar: 200 Μm.