Identity finally confirmed

Several years ago Ignacio Agudo published about a snail which he identified as Plekocheilus (Eurytus) from Santa Catarina state in Brazil. Based on a photograph of an immature specimen the species name aff. rhodocheilus Reeve, 1848 was added; a taxon of which only the type material exist from an unknown Brazilian locality.

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Now it appears that more specimens have been found and reared to adult stage. According to Agudo, the true identity of this species is completely different (but the external morphology is very similar): Mirinaba fusoides (Bequaert, 1948), family Strophocheilidae.

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Good to have this clarified and corrected. Note that this species appears to be eniantomorphic; both dextral and sinistral specimens have been found. This is a phenomenon quite rare, but seems to occur more often in Brazil as other examples (e.g., Corona) are known from that region.

Agudo, I., 2020. Plekocheilus (Eurytus) aff. rhodocheilus (Reeve, 1848) (Gastropoda: Pulmonata: Amphibulimidae) from Santa Catarina State, SC, Central Southern Brazil region: a case of taxonomic identity resolved. – Bioma, 5 (54): 37-47. (Link)

Type material of Cousin

Just published*: a paper on the type material present in the Brussels museum from Cousin, containing both species described by him and by Jousseaume.

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Type material is documented for 28 taxa described by Cousin and Jousseaume on the basis of material collected by Cousin in Ecuador. These taxa belong to 12 families (Achatinidae, Ampullariidae, Bulimulidae, Labyrinthidae, Lymnaeidae, Neocyclotidae, Orthalicidae, Planorbidae, Proserpinellidae, Scolodontidae, Solaropsidae, Succineidae). Type specimens and their labels are figured. In some instances, the specimen labels provide more precise locality information than the literature reference. Isomeria bourcieri var. lutea Cousin, 1887 is now considered a junior objective synonym of Isomeria bourcieri (L. Pfeiffer, 1853)“.

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The paper is an advance-online publication, the correct pagination numbers will follow when it is published in the printed issue later this year. It is a forerunner for a paper on Ecuadorian non-marine molluscs where, together with co-authors, we are still working on.
*There may be some confusion about the publication date. ResearchGate picked up the title of this paper already a while ago when I still had to make my final corrections to the proofs. Both the editor and myself were wondering how that was possible, as I already received requests for the full-text via ResearchGate.

Breure, A.S.H., 2020. Type material of taxa described by Cousin and Jousseaume in the Royal Belgian Institute of Natural Sciences, Brussels. – Folia Malacologica 28: 0-0 (advance online).

Taxonomy of Polygyratia

Freshly pressed: a paper by Salvador & Cavallari on this genus. Their abstract is as follows: “Herein, we present a taxonomic revision of the genus Polygyratia Gray, 1847, with a new systematic placement in Scolodontidae and containing only the species Polygyratia polygyrata (Born, 1778). We offer an updated morphological description and geographical distribution, based on museum specimens and occurrence data gathered from literature and online database iNaturalist. We synonymise P. charybdis Mörch, 1852 with P. polygyrata. The species is known only from Atlantic Forest areas in Bahia state, eastern Brazil. We exclude three other species from the genus Polygyratia, classifying them as: Systrophia (Systrophia) heligmoida (d’Orbigny, 1835) and S. (Entodina) reyrei (Souverbie, 1858), based on conchological features; and S. (E.) pollodonta (d’Orbigny, 1835), though tentatively, based on scant published data. Finally, we present the first report of S. (S.) heligmoida (d’Orbigny, 1835) from Brazil“.

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It is good to have this revision of Polygyratia, with its new classification to the Scolodontidae. Personally I would like to see additional research, anatomical and molecular, on the 3 species which are now (tentatively) classified by these authors in Systrophia.

Salvador, R.B. & Cavallari, D.C., 2020. Taxonomy and distribution of enigmatic ‘helicoid’ Polygyratia Gray, 1847 (Gastropoda, Stylommatophora). – Zoosystema and Evolution, 96(1): 91-101.

New fossil Cerion

Harasewych is well-known for his studies on Cerionidae. He described last year a new fossil from Aruba.

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Cerion uva gouldi is described as a new subspecies to include only fossil and subfossil Cerion uva from Aruba. The name Cerion uva arubanum Baker, 1924 had previously been applied to all Cerion uva from Aruba, living and fossil. A recent molecular study has shown that Cerion uva arubanum, a taxon based on living type material from Aruba, is a synonym of Cerion uva uva (Linnaeus, 1758), with which it shares a preponderance of mitochondrial haplotypes. Cerion uva was widespread on Aruba during the Pleistocene, but became extinct on that island and was subsequently re-introduced from a population near Willemstad in eastern Curacao by humans within the past 800 years. Earlier authors had recognized that fossil Cerion from Aruba differ in morphology from those living on the island today, with fossils being more similar to specimens from western Curacao and Bonaire, while those living on Aruba today are most similar to Cerion uva uva from eastern Curacao. Cerion uva gouldi may be distinguished from living populations of Cerion on Aruba on the basis of its cylindrical rather than ovate shell shape, its more closely spaced whorls, and its round aperture with a uniform rather than anteriorly expanded parietal rim“.

Harasewych, M.G., 2019. Cerion uva gouldi, a new fossil subspecies from Aruba (Gastropoda, Pulmonata, Cerionidae). – Proceedings of the Biological Society of Washington, 132(1): 35-39.

Land cover change in NE Mexico

Land-cover change and protected nature areas is not a subject that is well-studied. Vázquez-Reyes et al. recently published about it related to a region in northeastern Mexico.

Protected areas (PAs), priority terrestrial regions (PTRs) and priority terrestrial sites (PTSs) are strategies for conserving natural resources. However, loss of coverage on the peripheries can lead to isolation between these conservation areas. The present study analyzed the association of the change of coverage inside and outside 2 PAs, 5 PTRs and 128 PTSs in Tamaulipas with the richness and geographic distribution of 5 species groups (strict, semi-aquatic and tolerant hydrophiles, as well as gastropods and pteridophytes in 3 periods (1986, 2002 and 2011). In addition, we identified areas with similar species composition and socioeconomic-environmental factors related to the change in coverage. The highest richness and geographic distribution of aquatic plants occurred outside the conservation areas, while the greatest richness of ferns and gastropods was present inside them. The greatest loss of coverage occurred outside the El Cielo Biosphere Reserve and the Sierra de Tamaulipas PA. The loss of native cover increased in the last 30 years and is greater outside the conservation areas, therefore is necessary to propose and implement strategies to reduce the isolation of these areas“.

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Although no list is given of the gastropods studied, assumingly they were terrestrial species. This is a policy study rather than a taxonomical one, but for conservation purposes it may be of interest.

Vázquez-Reyes, C.J. et al., 2019. Biodiversity risk from land-cover change in terrestrial priority regions and protected natural areas in northeastern Mexico. – Revista Mexicana de Biodiversidad 90: e902726 (16 pp.).

A narrow escape?

Earlier this week I received some pictures from Gerard van Buurt (Willemstad, Curacao) showing a guave fruit brought to him with snails. The fruit came from a local supermarket. If he could possibly tell what snails they were? Van Buurt is a retired official of the Department of Agriculture on the island, and I have been in contact with him for quite some years.

The hunch was they were Succineidae, but he had no clue what species. As the sticker on the fruit indicated it was imported from the U.S.A., I contacted the owner of the supermarket chain who happened to reside in the Netherlands. To cut a long story short, the fruit came from Florida and was not only available in two shops on Curacao, but also on Aruba and Bonaire where the same chain also has shops. Alarmed by our inquiry the local manager had the fruits removed and checked.

Snails on Guava fruit 8976

Knowing that the suspected source was in the U.S.A., colleagues from USDA/APHIS were contacted for more information. They confirmed that the species is Calcisuccinea campestris (Say, 1818), which is known to be a pest species of fruit and horticultural crops. The risk of potential establishment of this species is one not worth taking.

Feeding this information back to Curacao, the danger of an unintentional introduction of yet another alien species in the Curacao malacofauna was fenced off thanks to an unknown attentive buyer of the infected fruit. Although this was a narrow escape, it is yet another example of how relatively easy it is to introduce snails via commercial activities to places where they don’t belong and can be harmful.

The concerted action of Gerard van Buurt (Curacao) and Francisco Borrero (USDA) is thankfully acknowledged.