Cyclodontina capivara, Simone, Luiz Ricardo L. & Casati, Rafael, 2013

Simone, Luiz Ricardo L. & Casati, Rafael, 2013, New land mollusk fauna from Serra da Capivara, Piauí, Brazil, with a new genus and five new species (Gastropoda: Orthalicoidea, Streptaxidae, Subulinidae), Zootaxa 3683 (2), pp. 145-158 : 149-151

Cyclodontina capivara new species

( Figs. 16–22 )

Types. Holotype MZSP 112448 ( Figs. 16–18 ). Paratypes MZSP 111837, 19 shells (sta. P1), MZSP 111838, 18 shells (sta. P1), MZSP 111845, 8 shells ( Figs. 19–20 ), USNM, 2 shells; MNRJ, 2 shells. All from type locality.

Type locality. BRAZIL. Piauí; Serra da Capivara ; Coronel José Dias municipality, close to Sítio do Mocó town, Cave Toca de Cima dos Pilão, 8°51’47.10”S 42°33’26.96”W (R. Casati col, 2012).

Diagnosis. Shell well sculptured axially, with ribs uniform and well-spaced; apex slightly pointed. Peristome with 6 somewhat equidistant, well-developed teeth, occupying ~70–76% of shell length.

Description. Shell of about 20 mm. Color pure white. Periostracum wanting. Outline slightly turriform; width ~30% of length. Protoconch of 2 whorls, opaque, tall, suture well-marked; sculptured by delicate and uniform reticulation ( Figs. 21, 22 ); occupying ~6% of shell length and ~26% of shell width; border protoconch-teleoconch clear, slightly prosocline. Spire of ~8 whorls, tall, being wider in two penultimate whorls; angle ~25 ( Fig. 19 ) to 35° ( Fig. 20 ); suture shallow but well-marked. Sculpture uniform series of axial, slightly prosocline, narrow ribs, from suture to suture, ~ 30 in penultimate whorl; interspaces between ribs ~5 times their width. Sculpture absent in inferior half of body whorl in young specimens ( Fig. 21 ), with low carina in periphery. Body whorl varying from equal ( Figs. 19, 20 ) to ~10% narrower ( Figs. 16–18 ) than two preceding whorls. Three spiral wide grooves corresponding to palatal tooth in ¼ whorl preceding peristome ( Figs. 17, 18 ). Peristome entirely deflected outwards, expanding ~20% width of preceding whorl; aperture slightly prosocline, ~10° related to longitudinal shell axis. Aperture oval, occupying ~20% of shell length and ~70–76% of width ( Figs. 16, 19, 20 ); greatly occluded by series of blunt and tall teeth ( Figs. 16, 19, 20 ), teeth fold-like, disposed rather perpendicularly to peristome; as follows: 2 teeth on inner lip, located somewhat equidistant from each other on inner lip, columellaris (inferior) tooth ~8 times longer than wide, almost straight, edge broader than base, disposed obliquely (distal end more anterior than posterior end), parietalis (superior) tooth about as long as inferior tooth, but slightly thinner and more perpendicularly organized; four palatal tooth, equidistantly located on outer lip, all them ~4 times longer than wide, edges slightly broader than base, palatalis superior (second tooth) with ~double height than remaining teeth; basalis tooth as smallest. Callus thick but planar, simple, widely attached to penultimate whorl ( Figs. 16, 19 ); fecal and urinary furrows narrow and shallow, but clearly visible in both sides of callus ( Fig. 16 ). Umbilicus wanting.

Measurements (in mm): Holotype ( Figs. 16–18 ): 19.2 by 5.9; paratypes MZSP 111845 #1 ( Fig. 19 ): 20.4 by 5.8; #2 ( Fig. 20 ): 17.0 by 5.5.

Distribution. Only known from type locality.

Habitat. Caatinga semi-dry environment; collected inside caves.

Material examined. Types. Non-type material from type locality MZSP: 112348, 10 shells, 112352, 12 shells, 112359, 11 shells, 112336, 9 shells, 112370, 7 shells, 112374, 8 shells, 112401, 35 shells, 112414, 40 shells, 112417, 40 shells, 112430, 50 shells, 112434, 20 shells, 112441, 20 shells.

Etymology. The specific epithet refers to the local of occurrence, the Serra da Capivara , being attributed in apposition.

Systematic remarks. Cyclodontina capivara has resemblance to some congeneric species that possess welldeveloped axial sculpture, which are only a small part of the Cyclodontina species ( Simone, 2006). It differs from C. cylindrica ( Baker, 1913) , from Ceará to Pernambuco, in having more developed teeth in peristome, mainly palatal ones, a more slender outline and axial ribs more spaced. It differs from C. gemellata (Ancey, 1901) , from Goiás, in being much slender, in having a more pointed spire and by the aperture being much smaller. It differs from C. scabrella (Anthony & Dohn, 1882) , from Paraíba, in having a slender outline, less regular axial ribs, and the aperture is narrower. Cyclodontina capivara also resembles Clessinia costata (Pfeiffer, 1848) , from Minas Gerais, differing in having more developed teeth in peristome, more pointed spire and less-spaced axial ribs. There is no other species in such C. capivara can be confused.

Young specimens of C. capivara are rare. They clearly show that the characteristic sculpture is restricted to the superior half of the teleoconch whorls ( Fig. 21 ), and that the inferior half (exposed only in the body whorl) is smooth.

Figures

FIGURES 16 – 23. Type shells. Figs. 16 – 22: Cyclodontina capivara n. sp. shell of types; Fig. 16, holotype MZSP 112448, apertural view (L 19.2 mm); Fig. 17, same, right view; Fig. 18, same, dorsal view; Fig. 19, paratype MZSP 111845 – 1, apertural view (L 20.4 mm); Fig. 30, same, # 2 (L 17.0 mm); Fig. 21, paratype MZSP 111837, young specimen, apertural view (L 6.5 mm); Fig. 22, same, detail of apex in profile (W 2.0 mm); Fig. 23, Rhinus gilbertus n. sp., holotype, detail of apex in profile (W 1.5 mm).