Stapafurdius, a new genus of Bulimulidae (Mollusca, Eupulmonata) from Bahia, Brazil, with two new species

The new genus Stapafurdius gen.  nov. is introduced collected from Bahia, Brazil, including two new species: S.  glaber sp.  nov., the type species, occurs in Ibicoara; and S.  costiferus sp.  nov., from Andaraí regions. The new genus includes species of about 10 mm, elongated shell, reticulated protoconch, elongated peristome, and wide umbilicus. Both species differ mainly by the sculpture, as S. glaber sp. nov. is smooth, while S. costiferus sp. nov. has strong axial sculpture. http://zoobank.org/C851695E-6BF1-4418-8D8A-8BC7D10CC2FE.


INTRODUCTION
Recent expedition of the collection team of the naturalist José Coltro in calcareous regions from Minas Gerais and Northeast Brazil has brought to light a quantity of new samples, promoting expansions on the geographic distribution of know species, as well as several new taxa (e.g., Simone, in press). This operation is presently facilitated by complete inventories of the Brazilian continental malacofauna (Simone, 2006;Birckolz et al., 2016), in which new taxa can easily be detected.
The present paper refers to samples collected in the central Bahia region, in a semi-dry environment, for which the analysis revealed to belong to a new genus, formally described herein. Two new species are easily detected, one from the Andaraí, and the other from the Ibicoara municipalities.
As the samples are composed only of shells, no information on the internal anatomy is so far possible. However, the shells are informative enough to base the taxonomical analysis. Some doubt, however, remains in the family attribution, an issue stressed in the Discussion section.

MATERIAL AND METHODS
The samples were donated dry and deposited in the malacological collection of the Museu de Zoologia da Universidade de São Paulo (MZSP). The specimens were carefully examined under stereomicroscopes and digitally photographed by Nikon and Canon cameras, as well as by AxioCam ERc5s coupled in the microscope. All images were processed in the Corel software, mainly PhotoPaint®, and by AxioVision multifocal software. A pair of young specimens were selected for Scanning Electron Microscopy; they were covered by gold and examined by ordinary methods, with main concern to the protoconch sculpture. The list of material examined is the type material mentioned in each species description. Most of the generic definition used in the Discussion was based on Pilsbry (1897-1898), beyond the indicated references.

Distribution:
Only know from type locality. Etymology: The specific epithet means "bearing ribs" in Latin, an allusion to the shell axial sculpture.

Measurements (in mm
Diagnosis: Shell rather cylindrical, sculpture strong axial cords.

DISCUSSION
There is almost no doubt that Stapafurdius gen. nov. is a new genus, as nothing similar exists in South America. The most similar genera are discussed below. The main problem is, however, to attribute a family to the new genus. Tentatively it has been considered Bulimulidae. However, this family has recently suffered radical changes, mostly based on molecular approaches (e.g., Breure et al., 2010;Breure & Romero, 2012;Bouchet et al., 2017). However, these changes have not been accompanied by efforts to provide visible diagnostic features to the taxa, precluding the analyses of taxa lacking molecular known sequences. Those papers (and references therein), however, are good bases for showing how weak is the orthalicoidean systematics, that some of considered genera are clearly polyphyletic, and they need to be divided. The introduction of new genera appears inevitable. The general bulimuloid shape of Stapafurdius gen. nov., and the peristome lacking teeth are the main reasons for considering it a bulimulid. However, as reported below, some of the genera that need to be compared by their conchological similarity belong to other orthalicoidean families.
The last whorl of Stapafurdius gen. nov., having an umbilicus and antero-posteriorly elongated peristome, is similar to Anctus Martens, 1860 (Simone, 2006: 173), considered a bulimulid or orthalicid, but it differs by the elongated spire and outline, and pale protoconch, as Anctus has obese shell, with dark, not-sculptured protoconch. Elongated peristomes are also found in some species of Moricandia Pilsbry & Vanatta, 1898 (Simone, 2006: 171-172), odontostomid, from which Stapafurdius gen. nov. differs in being much smaller, less elongated, and by the opened umbilicus; the elongated peristome of Moricandia actually is oblique, while that of Stapafurdius gen. nov. is longitudinal; the protoconch of Moricandia has a similar sculpture as Stapafurdius gen. nov., but Stapafurdius gen. nov. differs in having the sculpture still more delicate, and in having rounded whorls, while Moricandia has a blunt middle carina, keeping the apex rather umbilicated. The tall spire, the elongated peristome, the opened umbilicus, and the pigmentation also differ Stapafurdius gen. nov. from Bulimulus Leach, 1814, Protoglyptus Pilsbry, 1897, both bulimulid, and from Rhinus Martens, 1860, simpulopsid (Simone, 2006, and references therein;Breure & Romero, 2012). Rhinus and Bulimulus also have reticulated protoconchs, however their sculpture is rougher and slightly more irregular. The odontostomid subgenus Ventania Parodiz, 1940, also has species with elongated outline, and peristome lacking teeth, however, the elongated peristome and the opened umbilicus differ Stapafurdius gen. nov. from it. From the odontostomid Clessinia Döring, 1875, Stapafurdius gen. nov. differs in having the elongated peristome, the opened umbilicus, lack of palatal tooth in the peristome, and by more delicate protoconch sculpture, as Clessinia has clear predominance of strong axial cords. From the odontostomid Spixia Pilsbry & Vanatta, 1898, Stapafurdius gen. nov. differs by the elongated peristome (Spixia has a rounded one), in lacking peristome teeth (all Spixia have strong teeth in the aperture), by the cylindric anterior portion (Spixia has a continuous shell increment), and by the reticulated protoconch (Spixia has only strong axial cords as protoconch sculpture). From the odontostomid Bahiensis Jousseaume, 1877, Stapafurdius gen. nov. mainly differs by the external position of the peristome, dislocated because of the ample umbilicus, while Bahiensis has the peristome centrally positioned, practically lacking umbilicus; besides, Bahiensis has the peristome widely expanded, while Stapafurdius gen. nov. almost lack expansions; similarly, Stapafurdius gen. nov. has resem- blance of the protoconch sculpture of Bahiensis, despite being really more delicate; also, some Bahiensis have tooth-lacking peristome, but the peristome is always expanded, mainly anteriorly, which is not observed in Stapafurdius gen. nov. Two other bulimulid genera looks closer to Stapafurdius gen. nov.: Drymaeus Albers, 1850 and Bostryx Troschel, 1847. Stapafurdius gen. nov. differs from Drymaeus in having much smaller size (typical Drymaeus are ~ 30 mm), elongated outline (while Drymaeus have a clear bulimuloid shape), and elongated peristome; the protoconch of Stapafurdius gen. nov. differs in being much smaller and by the delicate sculpture, the protoconch of Drymaeus also has reticulate sculpture, but more robust, with stronger axial and spiral lines; additionally, typical Drymaeus lack or have pressed umbilicus. Bostryx is a genus occurring in the Andean region and near the Pacific coast of South America (no Bostryx occurs in Brazil - Pilsbry, 1898;Simone, 2006), and has a wider range of shapes and protoconchs; some species also have elongated shape, and some are even slightly cylindric, however, their peristome are never elongated; their protoconchs vary from smooth to reticulated, however, even the reticulated forms do not have a so delicate sculpture like that of Stapafurdius gen. nov.; the elongated forms of Bostryx usually have deep suture, so much that some species have scalariform last whorl. No other orthalicoidean genus can be somehow confused with Stapafurdius gen. nov. Focusing the protoconch of Stapafurdius gen. nov., it looks the single genus with so delicate sculpture, constituted of squared aligned pits, instead of being composed of minute axial and spiral lines like the other orthalicoideans that possess reticulated protoconchs.
The elongated peristome, based on the experience in collecting Anctus, is related to the habit of the snail to dovetail it in narrow dry bushes, very common in Northeast Brazilian region. The animal can, thus, hibernate during the dry season. The elongated peristome does not appear a defense mechanism, which more usually is the presence of teeth (Simone, 2018).
The protoconch of Stapafurdius gen. nov. is similar to most bulimulid and allied genera, in having the delicate net of spiral and axial lines equally predominating. The main exclusivity is the paucispiral condition (slightly more than 2 whorls) while most genera have more than 3 whorls.
The genus Stapafurfius gen. nov. so far appears to be endemic to the central Bahia dry region (Fig. 30). This present discovery joins several recent ones describing new species and even new genera (e.g., Simone, 2013, in press;Simone & Oliveira, 2021;Simone & Salvador, 2021), showing how weak is the knowledge on the Brazilian malacofauna. Possibly protective efforts must be implemented to preserve such species and environments. The proper description of the fauna is a first step.

ACKNOWLEDGMENTS
The samples studied were collected and donated by José Coltro-Jr. and his team of Femorale, for whom I am very grateful; additionally, he also commented some aspects of the taxonomy and of the paper. I also thank to two anonymous referees and the editor for comments, corrections and opinions that improved the paper. The collection was performed under IBAMA-ICMBio license 10560-1.