Research Article |
Corresponding author: Adrienne Jochum ( adrienne.jochum@gmail.com ) Academic editor: Thierry Backeljau
© 2019 Adrienne Jochum, Carlos E. Prieto, Marian Kampschulte, Gunhild Martels, Bernhard Ruthensteiner, Marko Vrabec, Dorian D. Dörge, Anton J. de Winter.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jochum A, Prieto CE, Kampschulte M, Martels G, Ruthensteiner B, Vrabec M, Dörge DD, de Winter AJ (2019) Re-evaluation of Zospeum schaufussi von Frauenfeld, 1862 and Z. suarezi Gittenberger, 1980, including the description of two new Iberian species using Computer Tomography (CT) (Eupulmonata, Ellobioidea, Carychiidae). ZooKeys 835: 65-86. https://doi.org/10.3897/zookeys.835.33231
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The present study aims to clarify the confused taxonomy of Z. schaufussi von Frauenfeld, 1862 and Zospeum suarezi Gittenberger, 1980. Revision of Iberian Zospeum micro snails is severely hindered by uncertainties regarding the identity of the oldest Iberian Zospeum species, Z. schaufussi von Frauenfeld, 1862. In this paper, we clarify its taxonomic status by designating a lectotype from the original syntype series and by describing its internal and external shell morphology. Using SEM-EDX, we attempt to identify the area of the type locality cave more precisely than “a cave in Spain”. The shell described and illustrated by
Zospeum suarezi was described from various caves in NW Spain. Study of the type material reveals that these shells are not homogenous in shell morphology. The holotype shell of Z. suarezi is imaged here for the first time. The paratype shell, illustrated by
Cave-dwelling species, microgastropods, shell variability, subterranean land snail
The Cantabrian-Pyrenean Region, encompassing 500 × 50 km of the northwestern part of the Iberian Peninsula, harbours a remarkable diversity of the cave-dwelling, land snail genus Zospeum. A number of species have been formally described. The oldest available name for a Spanish Zospeum species is Z. schaufussi von Frauenfeld, 1862. Since then, six more Spanish species have been described, viz., Zospeum bellesi Gittenberger, 1973; Z. suarezi Gittenberger, 1980; Z. biscaiense Gómez & Prieto, 1983; Z. vasconicum Prieto, De Winter, Weigand, Gómez & Jochum, 2015; Z. zaldivarae Prieto, De Winter, Weigand, Gómez & Jochum, 2015, and recently Z. percostulatum Alonso, Prieto, Quiñonero-Salgado & Rolán, 2018 (Fig.
Map indicating geographic position of type locality caves of described species of Zospeum in northern Spain. From left to right: Cueva del Puente de Inguanzo (Z. gittenbergeri sp. n., Z. praetermissum sp. n.), Cueva de La Herrería (Z. percostulatum), Cueva de Búho (Z. suarezi, syn. n. of Z. schaufussi), Cueva de Las Paúles (Z. zaldivarae), Cueva de Otxas (Z. biscaiense), Cueva de la Ermita de Sandaili (Z. vasconicum) and Cueva Molino de Aso (Z. bellesi). Source of DEM data: ALOS Global Digital Surface Model (AW3D30), JAXA.
Insufficient knowledge, causing doubts about the identity of two of these species, Z. schaufussi and Z. suarezi, has blocked further descriptions of this potentially very speciose radiation in a region where many caves are inhabited by two or three different morphotypes (
Zospeum schaufussi was the first Zospeum species reported from Spain. Detailed information about its provenance is lacking while its description is insufficient according to today’s standards. When
When
Subsequent to its description, Z. suarezi was reported from Bizkaia, Burgos and Cantabria (e.g.
Re-examination of the original material of Z. suarezi in
Material studied is housed in the following collections:
Maps were produced with the freely available QGIS software (
We emphasize that the
According to Emmanuel Tardy, curator at the
Additionally, as paratypes,
Shell measurements in mm (for methodology, see Jochum et al. 2015, fig. 1) of Zospeum schaufussi, Z. praetermissum and Z. gittenbergeri. Most shells of Z. schaufussi are type material of Z. suarezi Gittenberger, 1980, from the Cueva del Búho. Collection numbers are those presently used in
collection | SH | SD | HLW | PH | PD | W | SH/SD | HLW/SH | PH/SH | PH/PD | CT | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Z. schaufussi | ||||||||||||
lectotype | NHMW 71837 | 1.30 | 6.00 | 2.34 | ||||||||
Z. suarezi | ||||||||||||
holotype | RMNH.MOL.55383 | 1.21 | 0.78 | 0.62 | 0.42 | 0.42 | 6.00 | 1.55 | 0.51 | 0.35 | 1.00 | 2.41 |
paratype | RMNH.MOL.55384 | 1.07 | 0.71 | 0.56 | 0.40 | 0.40 | 5.55 | 1.51 | 0.52 | 0.37 | 1.00 | 2.34 |
paratype | RMNH.MOL.55384 | 1.20 | 0.73 | 0.66 | 0.43 | 0.41 | 6.00 | 1.64 | 0.55 | 0.36 | 1.05 | 2.41 |
paratype | RMNH.MOL.55384 | 1.00 | 0.64 | 0.56 | 0.37 | 0.35 | 5.50 | 1.56 | 0.56 | 0.37 | 1.06 | 2.39 |
paratype | RMNH.MOL.55384 | 0.99 | 0.67 | 0.56 | 0.40 | 0.39 | 5.15 | 1.47 | 0.57 | 0.40 | 1.03 | 2.25 |
paratype | RMNH.MOL.55384 | 1.04 | 0.70 | 0.59 | 0.36 | 0.40 | 5.55 | 1.48 | 0.56 | 0.34 | 0.89 | 2.37 |
paratype | RMNH.MOL.55384 | 1.20 | 0.70 | 0.62 | 0.33 | 0.39 | 6.20 | 1.72 | 0.51 | 0.27 | 0.83 | 2.49 |
paratype | RMNH.MOL.55384 | 1.11 | 0.74 | 0.59 | 0.42 | 0.41 | 5.90 | 1.50 | 0.53 | 0.37 | 1.00 | 2.45 |
paratype | RMNH.MOL. 55390 | 0.99 | 0.62 | 0.53 | 0.35 | 0.35 | 5.4 | 1.60 | 0.54 | 0.35 | 1.00 | 2.36 |
paratype | RMNH.MOL. 55390 | 1.04 | 0.70 | 0.59 | 0.36 | 0.4 | 5.5 | 1.49 | 0.57 | 0.35 | 0.90 | 2.35 |
mean/median | 1.08 | 0.70 | 0.59 | 0.38 | 0.39 | 5.68 | 1.53 | 0.54 | 0.36 | 1.00 | 2.37 | |
min | 0.99 | 0.62 | 0.53 | 0.33 | 0.35 | 5.15 | 1.47 | 0.51 | 0.34 | 0.83 | 2.25 | |
max | 1.30 | 0.78 | 0.66 | 0.43 | 0.42 | 6.2 | 1.72 | 0.57 | 0.40 | 1.06 | 2.49 | |
Z. praetermissum sp. n. | ||||||||||||
holotype | RMNH.MOL.55391 | 1.08 | 0.75 | 0.67 | 0.41 | 0.42 | 4.60 | 1.44 | 0.62 | 0.38 | 0.99 | 1.93 |
paratype | RMNH.MOL.339954 | 1.07 | 0.71 | 0.64 | 0.39 | 0.41 | 4.85 | 1.52 | 0.59 | 0.37 | 0.97 | 2.04 |
paratype | RMNH.MOL.339954 | 1.21 | 0.76 | 0.71 | 0.40 | 0.45 | 5.20 | 1.58 | 0.58 | 0.33 | 0.90 | 2.09 |
mean/median | 1.12 | 0.74 | 0.67 | 0.40 | 0.42 | 4.88 | 1.52 | 0.59 | 0.37 | 0.97 | 2.04 | |
Z. gittenbergeri sp. n. | ||||||||||||
holotype | RMNH.MOL.234166 | 1.49 | 0.92 | 0.89 | 0.53 | 0.58 | 5.50 | 1.62 | 0.59 | 0.35 | 0.90 | 2.03 |
Digital Images and measurements. Images were taken via a Leica DFC420 digital camera attached to a Leica M165C stereo microscope using Leica LAS V4.4 software.
Shell measurements were made on digital images as described in
Micro-CT. Internal shell morphologies were accessed using different micro-CT systems. The lectotype shell of Z. schaufussi (
Other Zospeum shells, except for the CT-imaged paratype of Z. suarezi (
Zospeum gittenbergeri sp. n. (
Scanning Electron Microscopy (SEM-EDX). SEM-EDX: Sections of the shell of the intact syntype Z. schaufussi (
Zospeum schaufussi von Frauenfeld, 1862.
Zospeum suarezi Gittenberger, 1980: 204. Syn. n.
Von Frauenfeld collection, a single undamaged syntype shell (
Von
Shell minute, ca. 1.3 mm, elongate-conical, with at least 5½ regularly coiled, convex whorls, suture deep; teleoconch smooth; aperture roundish-lunate; peristome thickened, elongate-roundish (not angular), closely adhering to spire; peristome height ca. 36% of shell height; umbilicus closed, umbilical depression deep, wrinkles behind apertural lip leading to umbilicus (seen in SEM-EDX Fig.
Zospeum schaufussi is easily separable from Z. biscaiense and Z. zaldivarae in shell and peristome shape and apertural characters, whereas Z. percostulatum is distinctly ribbed. Zospeum vasconicum and Z. bellesi are more similar, but the latter has no apertural barriers or even a suggestion of any. The former has a much less prominent columellar lamella and is clearly less tightly coiled. The species described here as Z. gittenbergeri, differs by its angular rather than rounded peristome and slightly developed lamella on the columella.
Clearly, the lectotype of Z. schaufussi strongly resembles Gittenberger’s topotypic Z. suarezi, to the extent that
Although our SEM-EDX analyses revealed no significant evidence linking the lectotype to a specific cave or potential cave region, this method, however, revealed some ecological information derivable from the sediment encrusting the shell. The sediment reflects a granitic context and minerogenetic processes (
Zospeum suarezi
—
Zospeum suarezi
—
Holotype. SPAIN Cueva del Puente de Inguanzo, Inguanzo, Concejo de Cabrales, Asturias, MGRS 30TUN4897097640; N43.315574, W4.860905; 230 m a.s.l.; 19 Feb 1979; G. Favre & R. Emery leg.;
Shell ca. 1.1–1.2 mm, conical with a roundish and moderately thick peristome, lacking apparent apertural barriers but with a small distinct lamella (denticle) in the parietal-columellar corner; internally, columella robust with a central lamella, a low upper columellar bulge and a basal umbilical ridge.
Measurements of holotype and paratypes are presented in Table
Differs from Z. schaufussi externally by its more conical shell with less tightly coiled whorls – adult shells having around 5 rather than 6 whorls of the same size – and a more pronounced lamella/denticle visible in the parietal-columellar corner in oblique view; internally by its robust columella and by its pronounced basal columellar ridge (above umbilical indentation). Zospeum praetermissum is easily distinguished from Z. biscaiense and Z. zaldivarae in shell and peristome shape and apertural characters, whereas Z. percostulatum is distinctly ribbed. Zospeum gittenbergeri differs by its broad, angular peristome and barely developed lamella on the columella. Zospeum vasconicum has a more rounded aperture with an almost uniformly-thickened peristome. Z. bellesi has no apertural barriers nor a columellar lamella.
The name, praetermissum, refers to the situation that the holotype shell was originally not recognized as distinct from Z. suarezi.
Only known from the type locality.
According to the records of the speleologist Gérald Favre (pers. comm. 2017), the collection site was located ca. 200 m from the cave entrance (also noted on the data label NHMG-Moll 96219 (978.363)). His field notes document that the collection area consisted of sandy substrate, some chestnut fragments and that the humidity level was low. The total length of the cave is 1500 m.
The label to the shell material
Zospeum material assessed in
Zospeum schaufussi
—
Holotype (
Holotype shell conical, larger than most Iberian Zospeum, SH nearly 1.5 mm with 5 1/2 moderately convex whorls. Parietal part of peristome straight and long, giving the peristome an angular rather than convex appearance. Internally, the lamella circumscribing the columella is very weak, but it is unclear if this is due to erosion or if it is covered by debris (Fig.
Measurements of holotype provided in Table
Differs from Z. biscaiense by the larger, more elongate shell and the absence of major apertural barriers; from Z. schaufussi (lectotype) by its long and angular parietal callus, straight, axially aligned columella and its small, non-extensive, tightly coiled lamella; in Z. bellesi, columellar elaboration is completely absent; from Z. vasconicum by its non-rounded aperture, more robust, axially aligned columella; from Z. zaldivarae by its more elongate shell, lack of apertural barriers; from Z. percostulatum by its non-costulate shell; from Z. praetermissum sp. n. by its long, parietal edge of the angular peristome and different columellar morphology.
The new species is named in honour of Prof. Edmund Gittenberger, in recognition of his pioneering work on Iberian Zospeum.
Only known from the type locality.
According to the records of the collector, Gérald Favre (pers. comm. 2017), the collection site was located ca. 200 m from the cave entrance. His field notes document that the area consisted of sandy substrate, some chestnut fragments and that the humidity level was low.
SEM-EDX spectroscopic images showing spectrum of elemental content in sediment encrusted on different regions of the lectotype of Zospeum schaufussi von Frauenfeld, 1862 (
We formally describe the specimen illustrated by Gittenberger as a separate species. We confine the type material to the one shell known from the type cave. Although
A number of confusing discrepancies surfaced in addressing
An additional source of confusion is that there are two caves with similar, but not identical names referring to the town of Inguanzo, which are situated within one kilometer of each other (Fig.
Map indicating geographic position of the two different Inguanzo-named caves on either side of the Rio Casaño: Cueva del Puente de Inguanzo (collection site of
Special gratitude goes to Anita Eschner (