Tag Archives: anatomy

An Omalonyx revisited

Arruda et al. (2016) recently published a revaluation of an Omalonyx species from Brazil. Species from this group are notoriously difficult to discern. “Omalonyx geayi Tillier, 1980 was originally described on the basis of specimens from Kaw swamp, French Guiana. This species distinguished from other of Omalonyx d’Orbigny, 1837: (i) by hermaphrodite duct twice as long and sacculate, without radial ducts but a funnel-shaped insertion on the ovariotestis, and (ii) by longitudinal wrinkled folds on the phallus inner wall. Two recent collections – from Trinidad and Carauari (Amazonas, Brazil) included specimens with ovariotestis and hermaphrodite duct morphologies similar to that originally described for O. geayi, but with phallus morphology not consistent with identification as O. geayi. A further eight lots, from Suriname, Ecuador, Brazil (Amazonas and Alagoas States), Bolivia and Cayenne-Kourou Road in French Guiana comprised specimens with phallus morphology analogous to O. geayi and ovariotestis and hermaphrodite duct similar to that of other Omalonyx species. Based on histological examination, and earlier phylogenetic analyses of morphological characters, we conclude that the ovariotestis and hermaphrodite duct conditions previously described for O. geayi were based on parasitized specimens. Accordingly, O. geayi is redescribed, and new information presented on the species’ wide distribution in South America”.

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Based on histological and anatomical research, the authors conclude that the original description was based on parasitised specimens in which the ovariotestis and proximal hermaphrodite duct were deformed. O. geayi as currently understood is occurring more broadly in South America than previously thought. The study was based on specimens from Trinidad, Suriname, French Guiana, Ecuador, and Brazil.

Reference:
Arruda, J.O., Barker, G.M. & Thomé, J.W., 2016. Revaluation of the taxonomic characters and distribution of Omalonyx gaeyi (Gastropoda, Succineidae). – Iheringia, Zoologia, 106: e2016019 (6 pp.). DOI: 10.1590/1678-4766e2016019

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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.

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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.

New Brazilian species (1)

Two papers were just published by Simone and Salvador, of which today the one about species from Minas Gerais. As usual these authors are keen to show the need for conservation of habitats which may house endemic or new species.

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“A sample of land snails was recently collected in a fragment of Atlantic rainforest, in the vicinities of the city of Nanuque (north of Minas Gerais state, Brazil), totaling 15 species. The following new species are herein described: Leiostracus carnavalescus n. sp. and Rhinus botocudus n. sp. (Bulimulidae), and Obeliscus boitata n. sp. (Subulinidae), the first two accompanied by anatomical descriptions. Moreover, the geographical ranges of some species are extended to Minas Gerais: Auris bilabiata, Bahiensis cf. bahiensis, Cyclopomops moricandi, Dysopeas muibum, Helicina boettgeri, Helicina variabilis, Prohappia besckei, and Rectartemon piquetensis. The discovery of new species in such a small forest fragment is a clear reminder of how little the Brazilian terrestrial snail fauna is known. It also points to the fact that these few remaining forest fragments may house many new and possibly endemic species and should, therefore, be properly preserved”.

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It may be noted that this paper was available on ResearchGate on the 19th April 2016, while the header states as publication date “30.IV.2016”.

Reference
Simone, L.R.L. & Salvador, R.B., 2016. Taxonomical study on a sample of land snails from Nanuque (Minas Gerais, Brazil), with descriptions of three new species. – Stuttgart Beiträge our Naturkunde A, Neue Serie 9: 9–30.

Bostryx tortoranus complex

Maria José Miranda, a young researcher from Argentina, has just published a new paper on some Bostryx species from that country. As it is advance access, the printed version will follow later.

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The abstract reads: “Morphology of the shell, radula, jaw, anatomy and sculpture of the inner wall of the reproductive system are described and compared for three species belonging to the Bostryx tortoranus species complex. On the basis of these characters, the following changes are proposed: Bostryx martinezi (Hylton Scott, 1965) is removed from synonymy with Bostryx tortoranus (Doering, 1879) and Bulimulus (Scansicochlea) cicheroi Hylton Scott, 1967 is transferred from synonymy with B. tortoranus to synonymy with B. martinezi. As a result of these changes, the number of species of Bostryx known from Argentina has increased to 19 species. Bostryx tortoranus and B. martinezi are redescribed, also the radula and anatomy of Bostryx rudisculptus (Parodiz, 1956) are described for the first time. The main distinctive morphological characters of the three species are: the structure of the shell’s protoconch and teleoconch, radular morphology, location of the secondary ureter opening, the length of the free oviduct with respect to the vagina and the epiphallus with respect to the penis and the bursa copulatrix duct’s inner wall sculpture. Bostryx martinezi and B. rudisculptus have restricted distributions and are ecologically endemic, whereas B. tortoranus has a wide distribution and is located in different dry ecoregions”.

Reference:
Miranda, M.J. (2015) Bostryx tortoranus (Doering, 1879) species complex (Gastropoda: Stylommatophora: Bulimulidae), a review of taxonomy and distribution of endemic species from Argentina. – Journal of Natural History, DOI: 10.1080/00222933.2014.981313 (advance access).

Polymita: a new book

For those who have ever wanted to see the astonishing colour diversity in Cuban tree snails of the genus Polymita, there is good news. After a very long and complicated process recently the new book by Adrián González finally appeared. It presents hundreds of colourful photographs of the six Polymita species and their natural environment, plus backgrounds on its malacohistory and the urging conservation issues for these over-hunted gems.

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Reference:
González Guillén, A., 2014. Polymita, the most beautiful land snail of the world. Carlos M. Estevez & Associates, Miami, 359 pp. (More info at the publisher: cecon14@aol.com)

Review of the genus Eucalodium

Fred Thompson published recently a review of the entire genus Eucalodium Crosse & Fischer, 1868 in Archiv für Molluskenkunde. It is a paper in his style with well-written text, good figures and distribution maps.

The abstract is here copied.

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For three species anatomical details are also presented.

Reference:
Thompson, F.G., 2014. A review of the Mexican and Central American land snails of the genus Eucalodium Crosse & Fischer (Pulmonata: Urocoptoidea: Eucalodiidae). – Archiv für Molluskenkunde 143: 69-105.

Colombian Megalobulimus

Jaramillo et al. (2014) recently published a paper which combined anatomical and molecular research on Megalobulimus oblongus (Müller, 1774) (Strophocheilidae) from Colombia.

The abstract reads: “In this work was done morphological and molecular analysis to 28 land snails of Megalobulimus oblongus, collected in different departments of Colombia, deposited in a reference collection. For morphological characterization, the animals were dissected in a stereomicroscope. The reproductive system and the shell were described. Measures were taken to structures of the reproductive system. Of the shell were described its shape, color, number of whorls and ornamentation and equally basic measures were taken using a digital caliper. For molecular analysis were used two mitochondrial markers, 16S rRNA and cytochrome C oxidase subunit I (COI). Only one haplotype was obtained for each marker, even for individuals of different and distant biogeographical regions. This study suggests that M. oblongus is in danger, therefore are urgent investigations about reproduction, population genetics and biogeography to clarify its situation in Colombia. It also demonstrates that the reference collections and tissue banks are sources of valuable information since they allow knowing aspects related with the species’ risk that serve as an input for the design of conservation actions”.

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The Colombian specimens were collected at six different sites, three of which are in Dept. Antioquia, and one in adjacent Caldas; two originated from the eastern departments. The genetic invariability found was linked to human transportation due to illegal trade. The conclusion that this species, widespread in South America, in endangered in Colombia seems premature. Not all species need to be conserved everywhere anytime in any political-administrative region; this might be a misconception of what biodiversity really is.

The data in Table 2 can be supplemented with the locality of Megalobulimus parafragilior Leme & Indrusiak, 1990: Brazil, São Paulo, Peruibe (MZSP 86740), as mentioned in the source from which the sequence was derived.

Reference:
Jaramillo Roldán, E., López Martínez, J., Ramírez, R. & Velásquez Trujillo, L. , 2014. Análisis morfológico del sistema reproductor e identificación molecular a través de los marcadores mitocondriales COI y 16S rRNA de Megalobulimus oblongus (Mollusca, Strophocheilidae) de Colombia. – Revista peruana de Biología 21: 79–88. http://bit.ly/1rGTAFs