A new species of Leiostracus ( Gastropoda , Pulmonata , Orthalicoidea ) from Espírito Santo , Brazil

A remarkable new species of pulmonate land snail was found in the collection of the Senckenberg Forschungninstitut und Naturmuseum Frankfurt (Frankfurt am Main, Germany) and is described here as Leiostracus faerie sp. nov. It can be easily identified by its small and translucent shell with fine axial light brown bands and its protoconch sculpture. It was collected in the Rio Doce (“Doce River”) region in Espírito Santo, Brazil, an area known for a high diversity and endemicity of land snails. This discovery shows how little this fauna is known and reinforces the importance of museum collections in the study of biodiversity and conservation.


ABSTRACT.
A remarkable new species of pulmonate land snail was found in the collection of the Senckenberg Forschungninstitut und Naturmuseum Frankfurt (Frankfurt am Main, Germany) and is described here as Leiostracus faerie sp.nov.It can be easily identified by its small and translucent shell with fine axial light brown bands and its protoconch sculpture.It was collected in the Rio Doce ("Doce River") region in Espírito Santo, Brazil, an area known for a high diversity and endemicity of land snails.This discovery shows how little this fauna is known and reinforces the importance of museum collections in the study of biodiversity and conservation.
An extraordinary new species of pulmonate land snail was fortuitously found in the collection of the Senckenberg Forschungninstitut und Naturmuseum Frankfurt (SMF; Frankfurt am Main, Germany) while browsing through the specimens of the genus Leiostracus Albers, 1850.It is part of an old collection (1914) and was collected in the Rio Doce ("Doce River") region, Espírito do Santo, Brazil (Fig. 1), an area of known high diversity and endemicity of many taxa (e.g., Rolim et al., 2006;maRques et al., 2013; for the land and freshwater mollusks, see simone, 2006).This new species is described and illustrated herein.

MATERIAL AND METHODS
The single specimen is a dry adult shell, housed at the malacological collection of the SMF.Unfortunately, as the material belongs to an old collection, precise habitat and locality data remain unknown.Measurements were made with a digital caliper; abbreviations: H, shell length; D, shell greatest width; S, spire length (excluding aperture); S', spire length (excluding body whorl); h, aperture height; d, aperture width.
Etymology.The name, from Old French, is allusive of the shell's fairy-like features: small, delicate and ethereal.
Distribution.Known only from the type locality.
Diagnosis.Shell small if compared with other species of genus, very delicate and translucent.Protoconch with reticulated sculpture.Color pattern composed of very fine light yellowish brown axial bands.

DISCUSSION
Leiostracus is an endemic South American genus, occurring in Guyana, Suriname and Brazil, and being particularly diverse in the eastern and southeastern regions of the latter (BReuRe, 1979;simone, 2006); its earliest record dates from the Middle Paleocene of Rio de Janeiro state, Brazil (salvadoR & simone, 2013).Leiostracus is traditionally classified in the family Bulimulidae, but some recent works have placed it in the family Simpulopsidae (e.g., BReuRe & RomeRo, 2012).
Leiostracus faerie sp.nov.can be easily identified by its small size (~14.5 mm in the holotype; the genus ranges from 20 to 30 mm) and its delicate and translucent shell, of whitish base color and with very fine light yellowish brown axial bands.There is only one species in the genus that resembles L. faerie in both shell shape and color pattern, namely, L. cinnamomeolineatus, known from the states of Pernambuco, Bahia (type locality) and Espírito Santo (simone, 2006; although all analyzed museum specimens that bear locality data come from Bahia).Leiostracus cinnamomeolineatus can be easily distinguished by its larger size, stronger and opaque shell with more numerous and stronger axial brown bands, narrower umbilicus and usually broader aperture (but there is some variation in aperture shape).A striking difference resides in the protoconch: L. cinnamomeolineatus shows the common protoconch sculpture for the genus (BReuRe, 1979;salvadoR & CavallaRi, 2013), i.e., broad, parallel and strongly prosocline wrinkles only on the upper portion of whorls, disappearing towards the median region and giving place to very fine spiral lines.
The completely reticulated protoconch seen in L. faerie (Fig. 2) is very unusual, although it is common in Pseudoxychona Pilsbry, 1931, which is either considered a subgenus of Leiostracus or a separate genus (BReuRe, 1979;simone, 2006).The present specimen lacks the typical strong carina of Pseudoxychona and displays a markedly convex whorl profile instead of a straight one with a clearly conical spire.Conservatively, we classify the new species in the genus Leiostracus.
As noted, L. faerie was collected in the Rio Doce region in Espírito Santo, a place known for a high diversity of land snails and by many endemic species, notably among the orthalicids: a good example is the already mentioned genus Pseudoxychona, since two of its four species are endemic to the Rio Doce region (simone, 2006).

Fig. 1 .
Fig. 1.Map of the state of Espírito Santo and the region covered by the Doce River (Rio Doce, in Portuguese) (BA, Bahia; MG, Minas Gerais; RJ, Rio de Janeiro).