A new genus and species of cavernicolous Pomatiopsidae ( Mollusca , Caenogastropoda ) in Bahia , Brazil

Spiripockia punctata is a new genus and species of Pomatiopsidae found in a cave from Serra Ramalho, SW Bahia, Brazil. The taxon is troglobiont (restricted to subterranean realm), and is characterized by the shell weakly elongated, fragile, translucent, normally sculptured by pus‐ tules with periostracum hair on tip of pustules; peristome highly expanded; umbilicus opened; radular rachidian with 6 apical and 3 pairs of lateral cusps; osphradium short, arched; gill filaments with rounded tip; prostate flattened, with vas deferens inserting subterminally; penis duct narrow and weakly sinuous; pallial oviduct simple anteriorly, possessing convoluted by‐ pass connecting base of bulged portion of transition between visceral and pallial oviducts with base of seminal receptacle; spermathecal duct complete, originated from albumen gland. The description of this endemic species may raise protective environmental actions to that cave and to the Serra Ramalho Karst area. Key-Words: Pomatiopsidae; Spiripockia punctata gen. nov. et sp. nov.; Brazil; Cave; Troglobiont; Anatomy.


IntroductIon
The family Pomatiopsidae is represented in the Brazilian region by only two species of the genus Idiopyrgus Pilsbry, 1911 (Simone, 2006: 94).However, the taxon is much richer in remaining mainland areas, with both freshwater and semi-terrestrial habits (Ponder & Keyzer, 1998;Kameda & Kato, 2011).Common features of the pomatiopsids are small size (smaller than 15 mm), elongated to short spired, and smooth shell with paucispiral protoconch.The main distinction from other rissooideans is the diaulic pallial oviducts of the females; i.e., the typical pallial oviduct has two separate openings to the pallial cavity (Davis, 1967(Davis, , 1979;;Ponder, 1988).
An enigmatic tiny gastropod has been collected in caves from the Serra Ramalho Kars area, southwestern Bahia state, Brazil.It has a pretty, fragile, translucent shell in such preliminary gross anatomy, which already reveals troglobiont adaptations, i.e., depigmentation, lack of eyes and small size.The sample has been brought by Maria Elina Bichuette, who is specialized in subterranean fauna.Complementary analysis revealed a new pomatiopsid for which no known genus can be attributed.Both genus and species are hereby formally introduced, including a detailed anatomical investigation.The description of this new taxon is not only academically urgent, but the cave is also threatened for economic reasons.The description of an endemic species helps in the argumentation for preserving this fragile location.

MAterIAl And Methods
All specimens were fixed in 70% Ethanol.The dissections were performed under a stereomicroscope by standard techniques, with the specimens immersed under fixative.Digital photos of each step of the dissection were obtained, as well as drawings aided by a camera lucida.A scanning electron microscope (SEM) was employed to view details of the shell and radula in the Laboratório de Microscopia Eletrônica of Museu de Zoologia da Universidade de São Paulo.

Family Pomatiopsidae Genus Spiripockia new genus
Diagnosis: Turbiform shell with highly expanded peristome.Walls translucent, smooth except for pustules containing hair-like projections of periostracum.Freshwater environment.
Description: Outline turbiform to slightly turriform.Protoconch paucispiral, of single whorl.Outer surface simple, except for small pustules distributed in somewhat spiral alignment, absent in some specimens (surface totally smooth).Peristome highly expanded and sprayed except for implantation on columellar surface.Umbilicus somewhat opened.Operculum thin.Pair of strong ventral retractor muscles of snout.Salivary gland reduced.Gonoducts closed (tubular); oviduct with bypass in posterior region.Spermathecal duct originated from albumen gland.
Type species: S. punctata new species.
List of included taxa: S. punctata new species.

Etymology:
The generic epithet is a contraction of Latin words spiri, from spira, and pocillum a little cup.Meaning something like a spiral small cup.This name is also used by my father, Egydio do Carmo de Simone, to designate any female pet in which he does not know the name.
Pronunciation: in English terms the genus must be vocalized as "speereepowqueeah".Circulatory and excretory systems (Fig. 31): Pericardium narrow, located transversely between stomach and pallial cavity (Fig. 22: pc), volume ~1/20 of that of visceral mass; auricle anterior, small, just posterior to posterior end of ctenidial vein; ventricle posterior, simple.Kidney minute, weakly smaller than pericardium, located on right side of pallial cavity posterior end; inner tissue totally solid, white.Nephrostome (ne) small, transverse, located close to pericardium.
Digestive system 28) Odontophore muscles 28): mj, pair of jaw and peribuccal muscles, working also as odontophore protractors, originating in lateral and ventral region of mouth, running towards posterior as part of oral tube along ~half odontophore length (Fig. 24), inserting in latero-ventral mid region of odontophore cartilages (Fig. 26); m2, pair of posterior retractor muscles of odontophore (Figs.24-25), narrow, originating in lateral region of haemocoel inner surface, in its middle level, running towards anterior a distance slightly longer than buccal mass length, inserting in postero-lateral region of odontophore cartilages (Fig. 28); m4, pair of main dorsal tensor muscle of radula (Fig. 28), broad and thick, surrounding outer lateral surface of odontophore cartilages, originating from their ventro-lateral surface, inserting in lateral edges of subradular cartilage in its region in buccal cavity, and also in radular sac region preceding buccal cavity (Fig. 28: ir); m5, pair of secondary dorsal tensor muscles of radula (Figs. 26,28), narrow and thick, originating in posterior edge of odontophore cartilages, running towards medial and anterior, between cartilages, inserting in ventral side of radular ribbon in its region exposed in buccal cavity (Figs.28: is); m6, horizontal muscle, thin and wide, connecting ventral edge of both odontophore cartilages along ~75% of their length (Fig. 28); m10, pair of ventral as lateral tooth and ~40% narrower, general form as rod curved inwards at tip, tip flattened, bearing ~13 (inner) and ~10 (outer) terminal cusps of similar characters as lateral tooth cusps.Salivary gland small (Figs.23-24: sg), white, with maximum length ~half buccal mass length, and sometimes smaller; about 3 times longer than wide, tip rounded; salivary aperture in postero-lateral region of oral cavity (Fig. 25: sa).Dorsal folds of buccal mass (Fig. 25: df ) smooth, simple, wide, located close to each other.Esophagus simple and sinuous along haemocoel , generally with anterior glandular enlargement (Fig. 24), but sometimes (~30%) with same width along length; most remaining esophageal inner surface simple, lacking folds; posterior esophagus (Fig. 22: es) narrow, inserting in ventral-mid region of stomach.Stomach dimensions and positions above described (visceral mass); possessing main gastric chamber posterior, with rounded posterior surface, and narrow style sac (Figs. 22: ss), with ~half remaining gastric dimensions.Style sac totally separated from intestine; esophagus inserting just ventrally to origins of style sac and intestine, on anterior stomach side; duct to digestive gland as wide as posterior esophagus, originating at short distance posterior to esophageal insertion (Fig. 22: dd), running towards posterior.Intestine originating dorsally and at left from esophageal insertion (Fig. 22: in), with ~double esophagus width, and at left from style sac; running surrounding externally style sac up to dorsal region of kidney, broadening in region preceding pallial cavity.Rectum, fecal pellets and anus above described (pallial cavity).Fecal pellets formed only after renal portion of intestine (Figs. 11,22).
Female (Figs. 22,32): Visceral structures similar to those of males; ovary (oy) somewhat broader than testis.Visceral oviduct very narrow, running along middle level of columellar surface of visceral mass ~half whorl (vo).Visceral oviduct inserting terminally in complex posterior region of pallial oviduct (Fig. 32) in bulged region of oviduct (co) with simple glandular walls and hollow inside.This bulged region continuing to albumen gland (ag) strongly curved in ~180°.Spermathecal duct (of ) originating in ventral-left side of albumen gland, very narrow but with thick walls, running along right edge of pallial cavity ventral to remaining pallial oviduct ~90% of pallial cavity length; opening simple by side and ventral to main female pore (Figs. 22: fp).Seminal receptacle (rs) bulging subterminally in posterior region of pallial oviduct, possessing two successive bulbs or sometimes horseshoe-shaped; inserting by narrow duct in adjacent left side of posterior end of capsule gland.Sperm duct, or bypass (sd) as convoluted duct connecting anterior region of bulged region of oviduct (co) with base of seminal receptacle (rs); posterior half clearly narrower, gradually broadening in anterior half.Capsule gland (cg) occupying ~80% of pallial oviduct length; walls thick glandular, white, lumen flattened (Fig. 22); short terminal atrium with walls weakly thick, tapering up to female pore.Female pore shortly siphoned, papilla-like, turned anteriorly, located close to and at right of anus.No special female genital structure in head-foot .
Central nervous system (Figs. 30,33): Nerve ring located just posterior to buccal mass, with pedal ganglia weakly more anterior (Fig. 23: nr) than remaining ganglia.Each cerebral ganglion (ce) oval, with size equivalent to esophageal section; cerebral commissure narrow, with ~half-length as each ganglion.Pleural ganglia (pl) with ~half size of cerebral ganglia, located just ventral to them.Each pedal ganglion (pn) weakly larger than cerebral ganglion, somewhat spherical, located very close to each other (pedal commissure extremely short).Cerebro-pedal and pleuro-pedal connectives about as long as pedal ganglia (Fig. 30).Subesophageal ganglion (su) with ~half pleural ganglion size, located a distance from right pleural ganglion equivalent to 1.5 times each cerebral ganglion length.Pair of statocysts (sy) located in ventro-posterior side of pedal ganglia; with large, single statolith inside.Single pair of tentacular nerve (tn), lacking optical nerve.
Distribution: Only known in the type locality (Lapa dos Peixes cave).
Habitat: In a cave surrounded by Caatinga semi-arid environment, attached to rocks inside a small stream.

dIscussIon
Spiripockia punctata is the second troglobiont gastropod described in Brazilian territory.The first one is a relative taxon, Potamolithus troglobius Simone & Moracchioli, 1994, a Hydrobiidae from Ribeira Valley, southern São Paulo state.Both species share the characters to consider them as troglobiont -the total lack of pigmentation and eyes, and small sizeand the freshwater environment.In light of the enormous quantity of caves in the Brazilian region, it is difficult to believe that only 2 troglobiont gastropod species exist.Bichuette & Trajano (2003) cited at least five more troglobiont species, all belonging to Hydrobiidae and probably to the genus Potamolithus Pilsbry, 1911, occurring in Ribeira Velley, SE Brazil.Though, certainly many more studies on this issue and urgent preservation of cave environments are necessary.I can affirm that the MZSP collection already has some samples of troglobiont rissooideans and even pulmonates waiting for study.
Spiripockia punctata has no South American species with which it can be confused.The set of conchological features are so far exclusive and sufficiently distinctive to erect a new genus.From the family Pomatiopsidae, the only two species hitherto described belong to the genus Idiopyrgus -I.rudolphi Haas, 1838 and I. souleyetianus Pilsbry, 1911(Simone, 2006), from which S. punctata differs in having a shorter and wider shell, fewer whorls, peristome more expanded, umbilicus wider, and the sculpture of most specimens of pustules with periostracum hair in them (10)(11).The radula and genital part of the anatomy of I. souleyetianus has been investigated (Rey, 1959;Malek, 1983), which permits some extra-shell comparison.The operculum of S. punctata has a more central nucleus.Its osphradium is much shorter and curved.Spiripockia punctata also has the insertion and pallial origin of the vas deferens in the prostate gland in a subterminal manner (Fig. 31: vd), however, that of I. souleyetianus is inserted and originated at mid-level of that gland.The penis is somewhat similar, with totally closed (tubular) duct, but the penis duct of S. punctata appears to be more convolute.The contrary happens in the seminal vesicle, such as in the case of I. souleyetianus whose seminal vesicle is apparently much more coiled.Related to the pallial oviduct, S. punctata lacks a clear separation between albumen and capsule glands (Fig. 32), as happens in I. souleyetianus; the bypass duct (sd) is much more coiled in S. punctata, and its seminal receptacle is connected directly to the pallial oviduct, while that of I. souleyetianus is connected to the visceral oviduct; S. punctata lacks a small secondary receptacle, which is present in I. souleyetianus; the spermathecal duct (of ) has its origin in the end of the albumen gland, close to insertion of the visceral oviduct in S. punctata, while that of I. souleyetianus is originated from the receptacle (also known, in rissooideans, as spermatheca or bursa copulatrix).Actually, the arrangement of the posterior region of the pallial oviduct of I. souleyetianus looks more like the pattern of the family (Davis, 1967(Davis, , 1979;;Ponder, 1988;Davis et al., 1992) than that of S. punctata, with the spermathecal duct connected to the pallial oviduct instead to the receptacle.In this point of view, the name "spermathecal duct" is not totally accurate; however the name was maintained in order to permit further comparisons and to suggest homology.This singularity of S. punctata is another indication of generic separation, beyond those features of the shell.
With respect to the radula, Spiripockia punctata possesses the normal pattern of the family (Ponder & Keyzer, 1998), which includes the lateral cusps in the rachidian and the basal lateral expansion of the lateral toot base.It differs in number and form of the cusps, as normally found amongst closely related species.

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Mouth in anteroventral end of snout(Fig.23: mo).Pair of strong ventral retractor muscles of snout and mouth; originating in middle level of haemocoelic ventral floor; running close to median line towards anterior, flanking ventral surface of buccal mass, passing through nerve ring(Figs.23, 33); inserting along ventral wall of snout, close to ventral border of mouth.Buccal mass bulged, occupying entire snout inner surface and ~1/3 of haemocoelic volume.Pair of jaw plates (Fig.25: jw) somewhat separated from each other; each jaw oval and very thin, translucent.Odontophore spherical, with ~half of buccal mass volume.