Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 September 2021 | 13(11): 19660–19662
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7431.13.11.19660-19662
#7431 | Received 13 May 2021 | Final received
24 June 2021 | Finally accepted 08 September 2021
Austroborus cordillerae (Mollusca: Gastropoda)
from central Argentina: a rare, little-known land snail
Sandra Gordillo
1 Universidad Nacional de Córdoba, Facultad de Filosofía y Humanidades, Museo de Antropología,
Córdoba, Argentina.
1 Consejo Nacional de Investigaciones
Científicas y Tecnológicas
(CONICET), Instituto de Antropología de Córdoba
(IDACOR), Avda, Hipólito Yrigoyen 174, X5000JHO,
Córdoba, Argentina.
sandra.gordillo@unc.edu.ar
Editor: Anonymity
requested. Date of publication:
26 September 2021 (online & print)
Citation: Gordillo, S. (2021). Austroborus
cordillerae (Mollusca: Gastropoda)
from central Argentina: a rare, little-known land snail. Journal of Threatened Taxa 13(11): 19660–19662. https://doi.org/10.11609/jott.7431.13.11.19660-19662
Copyright: © Gordillo 2021. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Mincyt Project: Abordaje
multidisciplinario de la malacología
en la Provincia de
Córdoba, Ministerio
de Ciencia y Tecnología de
la Provincia de Córdoba and
PICT 2016 0264.
Competing interests: The author
declares no competing interests.
Acknowledgements: This work is a contribution to
the project ‘Aproximaciones interdisciplinarias
para el estudio arqueológico
de sociedades cazadoras recolectoras, Córdoba, Argentina’ (PICT 2016 0264). Many
people collaborated at some stage of this research. Gabriela Boretto, Roxana Cattaneo, Marcela
Cioccale, Francisco Córdoba and Adan Tauber give me
information about the study environments. Mariana Adami,
Andrés Bonard, Thiago Costa, Alberto Cubría, Daniel Forcelli, Andrés
Izeta, Ronald Janssen, Víctor H. Merlo Álvarez, Julián Mignino,
Sergio Miquel, Ximena Ovando, Sebastián Pastor,
Eduardo Pautassi, Isabel Prado, Alberto C. Riccardi, Diego Rivero, Juan Rustán,
Fabricio Scarabino and Alejandro Tablado
help with information or logistical in relation to specimens that make up
different museum collections. To all of them my thanks.
To the
north-west of Córdoba, in the central region of Argentina, there is an
evolutionarily diverse land snail fauna dominated by endemic species. Such is
the case of the two most abundant and diverse genera Plagiodontes
and Clessinia (Pizá
et al. 2006; Pizá & Cazzaniga
2010; Cuezzo et al. 2013, 2018).
This
article concerns another land snail from the region, Austroborus
cordillerae, which is a little-known species
found infrequently (Klappenbach & Olazarri 1989; Gordillo et al. 2015). The lack of
information on this species means that its state of conservation has not yet
been categorized and it could be on the verge of extinction. This work
therefore provides updated information on the records of this species by
incorporating data collected in museums and new field findings.
Austroborus is recognized through three species with
disjunct distribution: Austroborus lutescens (King), which lives in Uruguay (Scarabino 2004), Austroborus
dorbignyi (Doering) from the south of Buenos
Aires, Argentina (Delhey et al. 2005) and Austroborus cordillerae (Doering), from the north-west of
Córdoba, Argentina (Gordillo et al. 2015). This genus is reduced in size (35 mm
high) compared to other representatives of the Strophocheilidae
family (i.e., Megalobulimus, 85 mm high). The
species A. cordillerae is somewhat larger than
the other two, and is characterized by the coloration of the peristome (intense
orange) and the sculpture of the proto-shell with intersecting radial and axial
ribs (like a lattice), with small globular thickenings standing out in the
intersection areas (Image 1). Unfortunately, these structures are not always
well-preserved due to natural erosion or wear. Our diagnostic references only
use the shell, since very little is known about the soft parts, except for a
short description of a section of the radula (maxilla) given by Klappenbach & Olazarri
(1989). The paratype of A. cordillerae is
housed in the Senckenberg Natural History Museum in
Frankfurt (Zilch 1971).
The new
records are 10 fossil (late Quaternary) shells from the Olaen
pampa (Image 2; 1,100 m) and one modern specimen (shell) from Ongamira (Image 2; 1,160 m). In addition, 14 specimens that
are part of museum collections or institutions were included (most of them are
from archaeological sites), together with nine more modern specimens from different
sources (specimens offered for sale via internet). When added to the previous
13 records summarized by Gordillo et al. (2015), these 34 new records
considerably increase the number of specimens documented so far.
Based on
all the information collected, it is interpreted that the development of the
species would have reached its peak in the Olaen
pampa, where it was recorded in late Quaternary sediments, probably of
Pleistocene age. After that, Austroborus
drastically decreased in number. This assumption is sustained through field
observations in the provenance locations of the shells and previous studies
carried out in the province of Córdoba to address climatic changes along the
late Quaternary using different geological and biological proxies (Carignano 1999; Andreazzini et
al. 2013; Córdoba et al. 2005; Giorgis et al. 2015;
Gordillo & Boretto 2020).
However,
despite its retraction in the Olaen pampa, we know
that the species continued to live during the late Holocene, since it was found
alive in the Achala pampa around 1885 and in the Ongamira valley in 1928 (Klappenbach
& Olazarri 1989).
Thus, other
factors would also have affected its retraction in the last millennium. In this
sense, towards the end of the Holocene, the colder and drier climate, and
practices associated with exotic livestock such as the burning of pastures,
could have been the causes of their extinction in both the Achala
and Olaen pampas. For the mountainous sector of
Córdoba, including the high pampas, there is a history of four centuries of
domestic grazing and man-made fires as a management practice, which have caused
erosion, reduction of vegetation cover and shrinkage of forests (Díaz et al.
1994; Renison et al. 2006; Cingolani
et al. 2008, 2013). Although there is no precise information on the effect of
fire on mollusk species in the region, field observations in the Olaen pampa made it possible to verify the presence of a
large number of burnt shells from different gastropod species (e.g., Plagiodontes, Clessinia,
Epiphragmophora) as a result of the fires that
raged in the region during the spring of 2020. Studies under controlled
conditions by other authors with other species have also shown that, in
addition to the death caused by forest fires, the altered habitat after a fire
also affects the survival of snails (Ray & Berger 2015). Thus, bush burning
over the years as an animal breeding practice must also be considered as a
factor or threat to these and other species living today.
Finally,
for Ongamira, a recent finding (March 2020) of a
modern Austroborus shell, together with
scattered data on specimens collected in the last 10 years (by collectors or
for sale), suggests that there could be a relict population of this species.
However, this information on ‘collecting’ should also lead us to reflect on the
effects of these very practices and to consider them as an additional threat;
one that could also severely affect some relict populations in this locality.
To
conclude, it appears that a set of factors (climatic and anthropic) acting over
time caused the retraction of this endemic snail.
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