Tag Archives: strophocheilidae

New fossils from Argentina

Just published: a paper by Miquel on continental gastropods from Argentina. “A new genus and two new fossil species of continental gastropods from the upper part of the Irene Formation—which is probably Huayquerian–Montehermosian (early Pliocene) and is exposed in the Quequén Salado River (Buenos Aires Province, Argentina)—are described: the new genus and species of freshwater gastropod Argentisioliella pardignasi (Cochliopidae) and a new species of landsnail of the family Bulimulidae (Bocourtia (Kuschelenia?) bonariensis). Argentisioliella pardignasi is morphologically related to those described for the Pebas Formation of Pliocene age. The specimens have bulloid morphology, long and narrow aperture, with a channeled peristome and two folds in the columellar wall. This is the first description of similar snails of the Pebas and Irene formations. Bocourtia (Kuschelenia?) bonariensis is the most ancient record for the genus, being recorded far away from the area of its current distribution (northwest Argentina). The specimen is an internal cast, with more than three convex whorls and a large aperture. Its distribution would coincide with the final phase of the Mio–Pliocene climatic change, when numerous terrestrial gastropods of Patagonian and Pampean provenance disappeared. A well-conserved specimen of the terrestrial snail Austroborus (Strophocheilidae Pilsbry), showing an almost complete shell, with more than 4.5 convex whorls, last whorl and large aperture, was also recorded. In the study area, this genus was present during the Pleistocene and Holocene, living in restricted areas of Argentina and Uruguay, with a disjunctive and relictual distribution“.

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Always interesting to see how palaeontologists are able to read those fragments. In this case the connection between Central Argentina and Pebas, in northeastern Peru on the Amazonian side, is remarkable. Thus a short but interesting paper.

Reference:
Miquel, S.E., 2019. A new genus and two new species of fossil continental gastropods from the early Pliocene of Argentina (Mollusca). – Ameghiniana 56 (2): 187–194.

Megalobulimus in Brazil

A short paper by Fontanelle et al. just appeared on one of the Brazilian species of this genus. “The taxonomical status of Megalobulimus toriii Morretes, 1937 from southeastern Brazil is reassessed herein. A large series of shells of M. toriii and M. yporanganus (Ihering & Pilsbry, 1901) were analysed for conchological features and measured for a principal component analysis. The material included recent shells and sub-fossil specimens (no living specimens or ethanol-preserved specimens could be procured). Megalobulimus toriii falls within the spectrum of morphological variation of M. yporanganus and is thus considered its synonym. Megalobulimus yporanganus was originally described from the Ribeira Valley in São Paulo state and its present distribution includes only other localities in this valley. However, the species is also known from Holocene archaeological contexts (shell mounds) and karst outcrops, with the oldest records dating from circa 10,800–9,200 YBP. Its past distribution extended southwards to the coast of Santa Catarina state”.

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Reference:
Fontanelle, J.H. et al., 2019. Taxonomic reassessment of Megalobulimus toriii (Gastropoda, Strophocheilidae). – Journal of Conchology, 43 (3): 313-320.

Contributions of Morretes

Recently a paper was published on the contributions of a Brazilian malacologist, Federico Lange de Morretes (Gernet et al., 2018). The text is in Portuguese, but there is also an abstract in English: “Frederico Lange de Morretes was born on May 5, 1892, in the municipality of Morretes, Paraná, Brazil. A renowned plastic artist, he was also an important malacologist, and his scientific production in the area made him a reference for Brazilian researchers. The main objective of this paper is to make a commented compilation of the malacological studies produced by him. He published 13 scientific papers in the area of malacology, eight of them related to the description of 25 new species, two new genera and three subgenera. He also wrote three institutional technical reports on activities carried out at the Museu Paulista and at the Museu Paranaense”. He died in 1954.

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The paper contains illustrations of the type material of the newly described taxa by Morretes, one figure of which is copied above. The authors made me aware there are two persons with similar names, Frederico Godefredo Lange de Morretes and Frederico Waldemar Lange. The first was a malacologist, the latter a palaeontologist; both worked in Museu Paranaense in the 1950s. Only the latter is mentioned in ‘2400 years of malacology’ (ed. 2018) but apparently with the wrong years of birth and death, which was the source of confusion for these two semi-homonyms.

Reference:
Gernet, M., et al., 2018. A contribuição de Frederico Lange de Morretes para a malacologia brasileira. – Arquivos de Zoología, 49 (3): 153-165.

 

A new Megalobulimus from Bolivia

Another single taxon paper by Simone appeared recently, describing a new Bolivian species.

Megalobulimus helicoides is a new species collected in Sucusuma village, Potosí department, Bolivia (Pulmonata, Acavoidae, Strophocheilidae). The species is mainly characterized by the deep suture, by the triangular open umbilicus, relatively small spire and proportionally narrow aperture. The sculpture of the protoconch and teleoconch, the red peristome and the deciduous periostracum indicate that the new species belong to the ‘Megalobulimus oblongus-complex’, which is uncommon in the Andinian region of South America”.

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Reference:
Simone, L.R.L., 2018. A new species of Megalobulimus from Potosí, Bolivia (Gastropoda, Strophocheilidae). – Strombus, 24: 1-4.

Fossil connections

Recently a review paper appeared by Hammouda et al. (2017), in which some links between northern Africa and South America are suggested. The abstract is as follows:

“Terrestrial gastropods occur in many North African localities in Eocene continental deposits. Here we analyse the faunal assemblage from the Hamada de Méridja Formation in southwestern Algeria, dated as Early to Middle Eocene on the basis of charophytes. The assem- blage consists of three closely related species that to date have been classified either in the extant Madagascan genus Leucotaenius v. Martens, 1860, or in the SW European Eocene genera Romanella Jodot, 1957 and Vicentinia Jodot, 1957. This is rejected for shell morphological and phylogeographical reasons, and a new classification as Maghrebiola gen. nov. is proposed. Maghrebiola is tentatively placed in the South American family Strophocheilidae, as species from the Early Eocene Itaboraí Basin of Brazil, currently placed in the genus Eoborus Klappenbach and Olazarri, 1970 in the family Strophocheilidae, superfamily Acavoidea, have a very similar shell habitus. This record possibly extends the known geographical range of the Strophocheilidae into the African continent during the Eocene. Immigration of this stock into North Africa during the Cretaceous via a still existing plate connection is assumed. An attribution of Maghrebiola to the African family Achatinidae is unlikely for shell morphological reasons despite certain habitus similarities, although the Priabonian genera Arabicolaria and Pacaudiella from Oman most likely belong into this family, and not to the Vidaliellidae as originally proposed. Possible causes for the very low diversity of the assemblage are mainly unfavourable living conditions, i.e. a relatively dry climate resulting in sparse vegetation and only occasional presence of water bodies, which may have had increased salinities, accounting for the lack of freshwater mollusks. The absence of any competing large gastropods may possibly have facilitated high intraspecific variability leading to sympatric occurrence of three closely related species, due to the animals occupying a wide range of available ecological niches. As the species discussed here have also been attributed to the genera Romanella and Vicentinia in the Vidaliellidae, we provide an appendix with annotated characterisations of most genera of the Vidaliellidae and list the nominal species assigned to them. This family is tentatively placed in the South American superfamily Orthalicoidea; its stock would have similarly immigrated from South America, but have successfully colonized mainly SW Europe, with only one Eocene species [Romanella kantarensis (Jodot, 1936)] recognized in Algeria”.

This paper presents a provoking view on the relations between northern Africa, soutwestern Europe and South America during the Eocene. Perhaps food for discussion among palaeontologists?

Reference:
Hammouda, S.A., Kadolsky, D., Adaci, M., Mebrouk, F., Bensalah, M., Mahboubi, M. & Tabuce, R., 2017. Taxonomic review of the ‘‘Bulimes’’, terrestrial gastropods from the continental Eocene of the Hamada de Méridja (northwestern Sahara, Algeria) (Mollusca: Stylommatophora: Strophocheilidae?), with a discussion of the genera of the family Vidaliellidae. – Paläontologische Zeitschrift, 91: 85-112.

Did Neotropical snails occur in Africa and Europe?

Fossils allow us a peek into the past, and although a lot remains uncertain and sometimes highly speculative (no molecules but only shell morphology to start with), they offer sometimes challenging views on worlds that have gone.

What we now call the Neotropics possibly once had a wider extension, and a team of Algerian and European scientists have made a study of Algerian shells that possibly give a clue. Hammouda et al. (2017) present a review of Eocene “Bulimes” and reached interesting but still tentative results.

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Their abstract reads “Terrestrial gastropods occur in many North African localities in Eocene continental deposits. Here we analyse the faunal assemblage from the Hamada de Meridja Formation in southwestern Algeria, dated as Early to Middle Eocene on the basis of charophytes. The assemblage consists of three closely related species that to date have been classied either in the extant Madagascan genus Leucotaenius v. Martens, 1860, or in the SW European Eocene genera Romanella Jodot, 1957 and Vicentinia Jodot, 1957. This is rejected for shell morphological and phylogeographical reasons, and a new classication as Maghrebiola gen. nov. is proposed. Maghrebiola is tentatively placed in the South American family Strophocheilidae, as species from the Early Eocene Itaboraı Basin of Brazil, currently placed in the genus Eoborus Klappenbach and Olazarri, 1970 in the family Strophocheilidae, superfamily Acavoidea, have a very similar shell habitus. This record possibly extends the known geographical range of the Strophocheilidae into the African continent during the Eocene. Immigration of this stock into North Africa during the Cretaceous via a still existing plate connection is assumed. An attribution of Maghrebiola to the African family Achatinidae is unlikely for shell morphological reasons despite certain habitus similarities, although the Priabonian genera Arabicolaria and Pacaudiella from Oman most likely belong into this family, and not to the Vidaliellidae as originally proposed. Possible causes for the very low diversity of the assemblage are mainly unfavourable living conditions, i.e. a relatively dry climate resulting in sparse vegetation and only occasional presence of water bodies, which may have had increased salinities, accounting for the lack of freshwater mollusks. The absence of any competing large gastropods may possibly have facilitated high intraspecic variability leading to sympatric occurrence of three closely related species, due to the animals occupying a wide range of available ecological niches. As the species discussed here have also been attributed to the genera Romanella and Vicentinia in the Vidaliellidae, we provide an appendix with annotated characterisations of most genera of the Vidaliellidae and list the nominal species assigned to them. This family is tentatively placed in the South American superfamily Orthalicoidea; its stock would have similarly immigrated from South America, but have successfully colonized mainly SW Europe, with only one Eocene species [Romanella kantarensis (Jodot, 1936)] recognized in Algeria”.

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The most recent, total overview of fossil and Recent Gastropoda was by Zilch, who classified the genera Romanella and Vidaliella with others in the “?Familia Anadromidae” within the Bulimulacea [currently Orthalicoidea] (Zilch, 1960); these genera are now placed in a family on their own, but based on their morphology there might be a resemblance with the Megaspiridae (e.g. Thaumastus). The link between the Mediterranean area and South America is further shown in the presence of the Clausiliid Neniinae, which the authors use as one of their arguments for their grouping of Maghrebiola with the Strophocheilidae. All this is an interesting but not implausible hypothesis.

References:
Hammouda, S.A., Kadolsky, D., Adaci, M., Mebrouk, F., Bensalah, M., Mahbouhi, M. & Tabuce, R., 2017. Taxonomic review of the “Bulimes”, terrestrial gastropods from the continental Eocene of the Hamada de Méridja (northwestern Sahara, Algeria) (Mollusca: Stylommatophora: Strophocheilidae?), with a discussion of the genera of the family Vidaliellidae. — Paläontologische Zeitschrift, (advance online) doi:10.1007/s12542-016-0333-5
Zilch, A., 1960. Gastropoda 2. Euthyneura. In: Schindewolf, O. (ed.) Handbuch der Paläozoologie, 6 (3–4): 401–834. Berlin: Borntraeger.

 

New record for Mirinaba

A new locality has been recorded for the species Mirinaba jaussaudi (Morretes, 1937) from Paraná state in Brazil.

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This species is now known from different ecoregions.

Reference:
Birckolz, C.J. & Gernet, M.V., 2016. New record of Mirinaba jaussaudi (Gastropoda, Strophocheilidae) in Paraná state, southern Brazil, and rectification of a known locality. – Strombus 23(1-2): 1-5.