Idiopyrgus adamanteus, Salvador & Silva & Bichuette, 2022
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publication ID |
https://dx.doi.org/10.3897/zse.98.90797 |
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publication LSID |
lsid:zoobank.org:pub:6CEC845A-7018-4DF3-ADE7-141B15FCBE05 |
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persistent identifier |
https://treatment.plazi.org/id/277BBC82-4F6F-4810-A0E0-7E23B7301D18 |
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taxon LSID |
lsid:zoobank.org:act:277BBC82-4F6F-4810-A0E0-7E23B7301D18 |
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treatment provided by |
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scientific name |
Idiopyrgus adamanteus |
| status |
sp. nov. |
Idiopyrgus adamanteus sp. nov.
Fig. 2A-H View Figure 2
Type material.
MZSP 158237 (holotype), LES 0027974 (14 paratypes, from type locality), LES 0027975 (3 paratypes, from type locality).
Type locality.
Brazil, Bahia state, Central municipality, Toca Bonita cave.
Distribution.
Known from four caves in Central municipality.
Etymology.
From Latin, meaning 'of diamond’; an allusion to the region in Bahia known as Chapada Diamantina, where all the caves in the species’ known distribution are located.
Diagnosis.
Elongated shell spire; narrow body whorl; more circular aperture when compared to congeners.
Description.
Shell small, truncatelloid, of translucent beige to whitish color. Protoconch bulbous and translucent, of fragile appearance (it is broken off in many specimens). Spire narrow. Shell smooth except for fine growth lines; growth lines can be more marked in some specimens, forming a light axial ribbing pattern (Fig. 2E, G View Figure 2 ). Suture deep; subsutural cord observed in one specimen (Fig. 2E View Figure 2 ). Whorl profile markedly convex, rounded. Whorls initially increasing regularly in size with growth, but final whorls are typically similar in size (Fig. 2A, D-G View Figure 2 ). Aperture small in proportion to body whorl; oval to circular, with a more acuminate end towards the upper lip insertion. Peristome complete; reflexed but not thickened. Shell rimate. Operculum translucent, of same color as the shell. Soft body white.
Measurements.
holotype: 6½ whorls, H = 5.3 mm, D = 2.3 mm; mean (n = 7), 6½ whorls (min 6, max 7), H = 5.6 ± 0.39 mm, D = 2.5 ± 0.12 mm.
Genetic data.
GenBank reg. nrs: COI, ON323464; 16S, ON359913; ITS2+28S, ON324828.
Remarks.
Idiopyrgus adamanteus sp. nov. is most similar in shell shape to I. souleyetianus and I. brasiliensis , but it can be diagnosed from them by the fewer number of whorls and the much narrower body whorl, as well as a more circular aperture (Fig. 1 View Figure 1 ). It can be distinguished from I. rudolphi by the deeper suture, more convex whorl profile and more circular aperture. It differs from the remaining congeners by its narrower shell, more elongated spire and smaller aperture (in proportion to body whorl).
Idiopyrgus adamanteus sp. nov. displays a fair amount of morphological variation in the shell, even in specimens from the same cave (Fig. 2A-D, F-H View Figure 2 ), like what is observed in many other freshwater truncatelloids. The shell and the spire of some specimens can be shorter (Fig. 2C View Figure 2 ) or taller and more elongated (Fig. 2D View Figure 2 ), the body whorl can be slighter wider (Fig. 2C, H View Figure 2 ), the shell sculpture can be more prominent (Fig. 2E, G View Figure 2 ), and a subsutural cord can be present (Fig. 2E View Figure 2 ).
Given its occurrence in four distinct caves of Central region (Bahia state), Idiopyrgus adamanteus sp. nov. is considered a troglophilic species rather than a strict troglobitic one. The region of Central is characterized by a dry vegetation type (Caatinga) and the caves represent good shelters for these animals, given their high-humidity microhabitats. Few collections were conducted outside the caves and, as such, this species occurrence outside subterranean habitats was not tested. Nevertheless, the lack of body pigmentation and the translucent shell of some specimens (Fig. 2A-H View Figure 2 ) are possible troglomorphisms, i.e., morphological traits typically observed in cave-dwelling gastropods ( Christiansen 2012; Trontelj et al. 2012; Salvador et al. 2022).
The caves of Central municipality and their surroundings are impacted by deforestation caused by subsistence agriculture, mining activities, and wind energy installations in the karst landscapes (Bichuette, pers. obs.).
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