Tag Archives: bostryx

Variability of Bostryx

Miranda published new data on the anatomy and shell shape variability of a Bostryx species. Her abstract reads as follows:
Introduction: The gastropod Bostryx torallyi shows high variability in shell shape and coloration. Subspecies of this organism have been described based on shell characters but, since they were slightly different, they were synonymized afterwards. Until now, shell variability has been analyzed only descriptively and its anatomy is still unknown.
Objective: In this study, I provide anatomical information of B. torallyi and apply a geometric morphometric analysis to evaluate the shell shape variation among specimens.
Methods: To accomplish this, type material and numerous lots were examined and dissected out. Additionally, relative warp analysis, based on 9 landmarks in ventral view of the shell, was performed using 80 specimens of 9 localities from Bolivia and Argentina.
Results: According to our results, geometric morphometrics is a suitable method to evaluate differences in shell shape among localities; for instance, distinctions in the shell were noticeable between gastropods of low and high altitudes. On the other hand, it was established that the coloration of this species is independent of large-scale factors since the examined specimens came from environments with similar conditions. Furthermore, the sculpture of the protoconch and anatomy of B. torallyi coincided with the other Argentinian species of the genus.
Conclusions: Therefore, I concluded that a geometric morphometric analysis of shell shape is a good complement to traditional qualitative description of the characteristics of the shell in this species
“.

Schermafbeelding 2020-06-08 om 15.34.01

As this study shows, Bostryx species can be very variable in their shell shape and colouration, with their anatomy still being the same. The study indicated that altitude is possibly related to the shell shape, but this needs confirmation from material sampled in the wider distribution area.

Miranda, M.J., 2020. Anatomy and shell shape variability in a land snail Bostryx torallyi (Stylommatophora: Bulimulidae). – Revista de Biologia Tropical 68(1): 218-229.

New record for Brazil

Salvador et al. just published a new paper, of which the abstract is “We report the first Brazilian record of Leiostracus demerarensis (L. Pfeiffer, 1861) from Pará and Maranhão states. The distribution of this species now comprises Guyana, Suriname, French Guiana, and northern Brazil. Furthermore, given the uncertainty in generic and familial allocation of this species (either Bostryx Troschel, 1847, Bulimulidae, or Leiostracus Albers, 1850, Simpulopsidae), we used the barcoding segment of the COI gene to ascertain its classification in Simpulopsidae, retaining it as Leiostracus demerarensis. Moreover, Simpulopsis luteolus (Ancey, 1901) is also reported for the first time from Pará state“.

Schermafbeelding 2020-05-01 om 09.15.24

The correct classification of this species was discussed a few years ago by Muratov & Gargominy in 2011, who considered it as a Bostryx species and based themselves on material collected in French Guiana. This new Brazilian record allowed the authors also check the molecular data, which confirmed its placement in Leiostracus. Hence a case where the DNA helped to judge between two conflicting views.

Reference:
Salvador, R.B. et al., 2020. First record of Leiostracus demerarensis (L. Pfeiffer, 1861) from Brazil (Gastropoda, Orthalicoidea), with a taxonomic reassessment. – CheckList 16(2): 507-512.

New Chilean Bostryx

Just published by Walther & Gryl, a new paper : “Bostryx koehleri n. sp. is described from a dry riverbed in the Atacama Desert north of Paposo, Chile. The new species has been found in an extremely arid region that gets some humidity only through mist from the nearby sea“.

Schermafbeelding 2020-01-15 om 14.30.56

As the species was found on the alluvial fan of a river, the authors state “it cannot be excluded that we are dealing with a fossil or subfossil species whose shells are washed out and deposited on the alluvial fan as the result of occasional flooding events“. Their suggestion is that the actual habitat of this species is higher up in the mountains.

Reference:
Walther, F. & Gryl, I., 2019. A new species of Bostryx (Gastropoda: Bulimulidae) from the Atacama Desert (Chile). – Archiv für Molluskenkunde, 143 (2): 111-115.

Photo of the day (177): Bostryx

These photos have been taken at Tambo de Viso in the Rio Rimac valley of Peru. They show Bostryx multiconspectus Breure, 2008, one of the carinated species that occurs in Andean countries. As this phenomenon, despite some examples from other parts of the world, is still poorly understood, we have conducted fieldwork several years ago. For various reasons the completion of a manuscript about this work has been delayed, but is foreseen for the near future.

Photos by courtesy of Philipp Meinecke and Nora Richter-Harder.

Photo of the day (176): Bostryx

These photos are part of a series taken at El Infernillo, Rio Rimac valley near Lima. They all depict Bostryx solutus Troschel, 1847, which shows some morphological variation at this locality. This variation is still poorly understood and may be due to ecological circumstances.

Photos by courtesy of Philipp Meinecke and Nora Richter-Harder.

Bostryx voithianus

In an overlooked paper, Martinez de los Rios (2017) published new data on the distribution of this Chilean species. His abstract reads: “Bostryx voithianus (Pfeiffer, 1847) is reported, for the first time since its description, from northern Chile. In the origi-nal description, a particular type locality was not given for this species, but to it was described as collected in Chile by Thomas Bridges for the Hugh Cuming collection. Herein, the type locality is assigned to the Chilean Coastal Range between the places Cuesta La Arena (28.5721° S) and Quebrada Honda (29.5952° S), northern Chile”.

Schermafbeelding 2018-11-08 om 08.10.52

These Chilean Bostryx species are still a relatively understudied group, despite some recent literature, and it is always good to have new reports on their occurrences.

Reference:
Martinez de los Rios, E., 2017. Rediscovery of Bostryx voithianus (Pfeiffer, 1847) (Gastropoda, Pulmonata) in northern Chile, with notes on the type locality. – CheckList, 13 (6): 1125-1129.

Bostryx voithianus rediscovered

Just published: a rediscovery of one of the very rare Bostryx species from the Chilean coast by Martínez (2017).

Bostryx voithianus (Pfeiffer, 1847) is reported, for the first time since its description, from northern Chile. In the original description, a particular type locality was not given for this species, but to it was described as collected in Chile by Thomas Bridges for the Hugh Cuming collection. Herein, the type locality is assigned to the Chilean Coastal Range between the places Cuesta La Arena (28.5721° S) and Quebrada Honda (29.5952° S), northern Chile”.

This paper gives a good overview of the historical background of the material collected by Bridges, and a useful indication of the localities. Only empty shells were collected, the challenge to check if the species is extant still exists.

Reference:
Martínez, E., 2017. Rediscovery of Bostryx voithianus (Pfeiffer, 1847) (Gastropoda, Pulmonata) in northern Chile, with notes on the type locality. – CheckList, 13 (6): 1125-1129. https://doi.org/10.15560/13.6.1125

New records of Chilean snails

Based on a small collection already made in 1982, Araya et al. have just published a paper on the snail fauna near Antofagasta.

New records for Bostryx holostoma (Pfeiffer, 1846), Pupoides minimus (Philippi, 1860), Stephacharopa calderaensis Miquel & Araya, 2013 and an unidentified charopid species are presented on the basis of specimens collected near the city of Antofagasta, in northern Chile. This is the first record for S. calderaensis after its description, extending its known distribution about 350 km northwards. Details on the protoconch of B. holostoma are presented for the first time, and this species extends its distributional range 145 km southwards. The microhabitat of these species in litho-refugia may explain the presence of these minute terrestrial mollusks in hyper arid northern Chile, further highlighting the need of additional studies of this neglected fauna”.

Especially the protoconch structure of Bostryx holostoma is interesting, as this reveals a spiral structure which is not present in other Chilean Bostryx species. As unpublished DNA results of species from this genus from different countries reveal, this genus may well be polyphyletic.

Reference:
Araya, J.F. et al., 2017. New records of terrestrial mollusks (Gastropoda: Stylommatophora) from Antofagasta, northern Chile. – Revista Mexicana de Biodiversidad, 88: 769-772.

More on Argentinian Bostryx

María José Miranda has recently published a new study on several Bostryx species from central western Argentina. As always, this is a thorough paper with lots of anatomical data.

Miranda15

The abstract reads: “The genus Bostryx Troschel, 1847 is endemic to South America, extending from Ecuador to Chile and Argentina. The southernmost Argentinian species of the genus that inhabit San Luis, San Juan and Mendoza provinces, specially the pre-Andes, Andes and Sierras Pampeanas mountain ranges, were examined. This is the first time the anatomy of Bostryx pastorei (Holmberg, 1912), Bostryx reedi (Parodiz, 1947) and Bostryx strobeli (Parodiz, 1956) has been described. Bostryx cordillerae (Strobel, 1874) is re-described regarding shell and anatomy due to new morphological data. The main differences among the species examined are based on shell characters. The distribution of Bostryx mendozanus (Strobel, 1874) and Bostryx cuyanus (Pfeiffer, 1867), other species found in this region, was also discussed”.

As she cited my publication about the subfamily Bostrycinae (Breure, 2012), I feel entitled to correct a possible misinterpretation. From her text it gives the impression that I have a very restricted view of this subfamily, leaving out all species not listed in my 2012 paper. The contrary is true. Page 3 of my paper explicitly stated that the list presented is incomplete, and further research should show which other species belong to this monophyletic clade. As the shell shape may be very misleading, which is corroborated in Miranda’s paper, I invited further research using anatomical and molecular data. Miranda’s paper is a welcome contribution to this end, although she has not presented phylogenetic data which could supplement the available data in GenBank. Hence there is room for further additions…

References:
Breure, A.S.H., 2012. The status of the genus Bostryx Troschel, 1847, with description of a new subfamily (Mollusca, Gastropoda, Bulimulidae). – ZooKeys 216: 1-3.
Miranda, M.J., 2015. The genus Bosoryx in central western Argentina: anatomical and distributional description of four of its southernmost species (Gastropoda, Bulimulidae). – Iheringia, Zoologia 105: 484–498.