Bittiolum guaranianum (Pimenta & Faria & Figueira & Fernandes, 2024)

Pimenta, Alexandre Dias, Faria, Raquel Garofalo De Souza, Figueira, Raquel Medeiros Andrade & Fernandes, Maurício Romulo, 2024, Unraveling another of the ‘ Big Fiveʹ: new species and records of Cerithiopsidae from Brazil (Caenogastropoda: Triphoroidea), Zootaxa 5494 (1), pp. 1-71 : 61

Bittiolum guaranianum (dʹOrbigny, 1841) comb. nov. and syn. nov. of Bittiolum varium ( Pfeiffer, 1840)

Cerithium guaranianum d’Orbigny, 1841: 443 , pl. 77, figs. 11–12 (figures in error, see remarks).

Bittium guaranianum : Mörch (1876: 95, not figured).

Cerithiopsis guaranianum : Tryon (1887: 171, pl. 35, fig. 39 (figure in error, see remarks).

Cerithium guaranianum : Lange-de-Morretes (1949: 79, not figured).

Cerithium guaranianum doubtful species: Houbrick (1974, not figured).

Type material. Syntypes: NHMUK 1854.12 .4.512 [17].

Type locality. Brazil, off Rio de Janeiro

Material examined. The types.

Remarks. Cerithium guaranianum was described by dʹOrbigny (1841) as abundant on the coast of Rio de Janeiro (southeastern Brazil), but curiously this name only appeared in the first catalogue of Brazilian mollusks ( Lange-de-Morretes 1949), being ignored in the subsequent catalogues by Rios (1970, 1975, 1985, 1994, 2009).

Houbrick (1974: 81) cited this name as a doubtful species whose type was not found and, based on the original illustration, assumed it to be an immature Cerithium atratum or a Cerithiopsis sp. Rosenberg (2009) listed it as Cerithiopsis guaraniana - dubious name. Tryon (1887) also illustrated this species, and allocated it to Cerithiopsis , but the provided image belongs to Cerithium peruvianum dʹOrbigny, 1841 (see below).

Without examining the types, the assumption by Houbrick (1974) was based on the original figures by dʹOrbigny (1841). However, examination of the cabinet of the dʹOrbigny Collection in the Natural History Museum, U.K., revealed that the type is available and that the original captions for the figures of Cerithium guaranianum and Cerithium peruvianum in dʹOrbigny (1841) were inverted, leading to all those misidentifications. The syntypes of C. guaranianum must be related to figure 9 in dʹOrbigny (1841), while the syntypes of C. peruvianum correspond to figure 11.

The syntypes of C. guaranianum are somewhat eroded specimens that correspond to the common littoral species Bittiolum varium ( Pfeiffer, 1840) ; we allocate it to Bittiolum guaranianum (dʹOrbigny, 1841) comb. nov., a junior synonym of B. varium .