Taxonomical study on a sample of land and freshwater snails from caves in central Brazil, with description of a new species

A sample of land and freshwater snails, mainly pulmonates, was recently collected in caves in Goiás and Bahia states, Brazil. Twenty-one species were found in the material. The following species are reported for the first time for Goiás state: Cecilioides consobrina (Ferussaciidae), Dysopeas muibum and Stenogyra octogyra (Subulinidae), Entodina jekylli and Prohappia besckei (Scolodontidae; also reported for the first time for Bahia state), Pupisoma dioscoricola (Valloniidae). A new species from Goiás is described herein: Gastrocopta sharae sp. n. (Gastrocoptidae). The new records and species addressed here constitute important findings, helping to fill distributional gaps and improving the knowledge of the local molluscan fauna, an essential step for future conservation efforts.


Introduction
The Brazilian continental molluscan fauna is still poorly known and is deemed to have so many undescribed species as to triple the presently known number (Simone 1999(Simone , 2006)).Since cave-dwelling invertebrates, in general, have received scarce attention from researchers in Brazil (Trajano and Bichuette 2010), it should be no surprise that cave-dwelling land and freshwater snails are even less known (a few exceptions are: Bichuette and Trajano 1999, 2003, Simone 2013, Salvador et al. 2016).This lack of study is alarming, especially from a conservationist point of view, since caves usually have very fragile ecosystems with a high degree of endemic species (Trajano 2000, Gallão and Bichuette 2012, Silva and Ferreira 2015).
Some recent expeditions (April/2012-January/2013) by Dr. M. E. Bichuette (Universidade Federal de São Carlos; São Carlos, Brazil) and her team to cave systems in Goiás and Bahia states, central Brazil, recovered many land and freshwater snails.This whole material was deposited in the malacological collection of the Museu de Zoologia da Universidade de São Paulo (MZSP, São Paulo, Brazil) and is studied here.The sample studied herein includes the description of a new species and occurrence of another twenty species, some of which are new records for Bahia and/or Goiás states.

Material and methods
All the material studied here was collected by M. E. Bichuette and her team and deposited in the MZSP.All the specimens were collected in caves (see Table 1 for all the localities) and comprise both empty shells and living an-imals.Brief descriptions of each locality can be found in Table 1, alongside their precise coordinates (see also Fig. 1).Localities from Goiás all fit into the Cerrado Biome, while those in Bahia are either Campos Rupestres (montane subtropical savannah) or a transition between the Cerrado and the Caatinga.
Identification was conducted based on the work of Simone ( 2006), the original descriptions, and additional material housed in the collection of the MZSP.Unfortunately, some species could not be identified beyond genus level, either due to poor preservation of the specimens or to very young age.The complete list of species, as well as a relation of all the studied material, can be found in Table 2. Species that deserve further notice, such as those with new records, are figured and discussed in the Systematics session below.Measurements were made with a digital caliper or with the aid of the Zeiss Axiovision SE64 Rel Table 1.List of all localities, i.e., the caves (or "grutas" in Portuguese), where the present material was collected, alongside their city/municipality, state, coordinates (see also Fig. 1), date of collection, the biome of the surrounding area, the microhabitat where the snails were collected and if there is a water body inside each cave.lower palatal tooth and columellar lamella.Umbilicus narrow, deep.
Discussion.The minute pupilloid shell and the pattern of apertural barriers, especially the presence of an anguloparietal lamella (formed by the fusion of the angular and parietal lamellae), place the present specimens in Gastrocopta.They are sufficiently different and easily diagnosable from all known Gastrocopta species in Brazil, which warrants the description of a new species: Gastrocopta sharae sp.n.Although each of the diagnostic features of G. sharae can be found separately in congeners (e.g., Pilsbry 1916Pilsbry -1918)), their occurrence together is unique for this species.
Likewise, G. sharae is easily diagnosable by its narrow gutter-like anguloparietal lamella (Fig. 4), slightly bent towards the palatal region of the aperture.All the Brazilian species present a bifid weak anguloparietal lamella, with the single exception of G. iheringi (Fig. 8).The latter also has a gutter-like lamella, but it is much broader and straight (i.e., not bent towards the palatal region).Moreover, G. iheringi is much taller than G. sharae, reaching a shell length of 2.5 mm; this might not seem a large difference at first sight, but differences of this magnitude are usually considered to be interspecific in the family.
Remarks.Despite the species being known throughout the Americas, the present record fills a gap in the species distribution (see the revision of Hausdorf 2007: fig.6).

Previously known distribution.
From the Caribbean Islands to central-northern Argentina (Miquel and Aguirre 2011) and Uruguay (Figueiras 1963).
Remarks.The present record is the first occurrence for Goiás and fills a gap in the species distribution in Central Brazil.Type locality.Brazil (restricted to Rio de Janeiro by Hidalgo 1870).
Remarks.The shell morphology of the present specimens compare very well to P. besckei; the size of the specimens from Goiás, however, is much smaller (D ~ 2 mm), slightly larger than half the normal size.This could represent a variation of the species in a cave environment, but the sample is too small to be of any significance.The present record extends the species distribution ca.600 km to the north.

Discussion
Many records reported here are the first for either Goiás or Bahia states (Table 2).These findings are especially important as they not only extend the geographical distribution of some species but also fill "distribution gaps" of some others; for instance, one species, Entodina jekylli, was previously known only from its type locality.The present records are among the few concerning molluscan cave fauna.Most caves in Brazil have no legal protection and are threatened by mining activities, but still harbor new discoveries (e.g., Simone 2013).Better known geographical distributions, as well as the presence of endemic taxa, can improve arguments for conservation.It is our hope that the present work is a step towards proper legal protection of such fragile ecosystems.

Table 2 .
List of all species found on the present material, with information on locality data, whether it is a new occurrence (species with new records are analyzed more thoroughly in the text) and record number of the MZSP collection.

Genus Stenogyra Shuttleworth, 1854 Stenogyra octogyra (Pfeiffer, 1856)
The present record fills a gap in the species' previously known distribution in Brazil.