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.

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Land snail holotypes in the IES, Havana

More and more institutions are making their holdings of type material available, either through publications or on the web. This is very useful as it greatly helps researchers to find the original material which may be needed for comparison.

Hernández Q. et al. have recently made an addition. “We present the first list of holotypes of terrestrial molluscs housed in the collection of the Institute of Ecology and Systematics, Cuba. The majority of holotype specimens come from collections belonging to Miguel L. Jaume, Oscar L. Alcalde, Alfredo de la Torre and Raúl P. Guitar. The type material of the collection has 66 taxa including species and subspecies. The genera represented in this type collection are Liguus, Farcimen, Cerion, Cryptelasmus, Idiostemma, Cubadamsiella and Opisthosiphon”.

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Although it is unfortunate that no pictures of these holotypes are included, which would eliminate the need for (possibly difficult) inquiries, the listing may be applauded as a first step.

Reference:
Hernández Q., M, et al., 2018. Catalogue of holotypes of terrestrial molluscs (Mollusca, Gastropoda) of the Institute of Ecology and Systematics, Havana, Cuba. – Poeyana, 507: 44-49.

Snails as snake prey

Several snake species are known to prey on molluscs, and in the Neotropics some examples are already known; e.g., in the recent book on Belizan land snails by Dourson et al. pictures are given of Sibon species consuming a Drymaeus.

By serendipity I found a paper by Sazima & Muscat (2016) on Dipsas snakes in Brazil, which are known to feed on snails and slugs. The first author had reported in the past about the challenges that these molluscs offer to their predator. Snails must be removed from their shell and slugs release plenty of mucus, making snail handling time-consuming and handling slugs poses the risk of sticking to the substratum. Most observations are based on laboratory conditions, but this paper describes how newly hatched snakes are feeding on snails under natural conditions.

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The (unwilling) victims in these cases were respectively Bulimulus tenuissimus (d’Orbigny, 1835) and Helicina angulata G.B. Sowerby, 1873. Both observations were made in Sao Paulo state in different forests.

Reference:
Sazima, I. & Muscat, E., 2016. Shelled baby food: Newly hatched goo‐eating snakes of the genus Dipsas (Squamata: Dipsadidae) prey on snails in nature. – Herpetologia Brasileira, 5 (3): 63-64. 

New Idiostemma from Cuba

It is described the new species Idiostemma frankei into the subgenus Maceo Pilsbry & Vanatta 1898, with type locality at Farallones de Moa, on the northeastern region of Holguín province. For diagnosis were used conchological characters, that make it different from the rest of species into this genus because have whorls almost flattened or plane and semitransparent, with fine ribs on surface of shell. Columella with well-developed lamellae on “S” form, ornamented by ribs like cords that crossing on upper part on both side of the wall, give striated appearance”.

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The holotype is in the Instituto de Ecologia y Sistemática, CZACC8.1.302.

Reference:
Fernández, A. & Suárez, A., 2018. New species of Idiostemma Pilsbry & Vanatta, 1898 (Mollusca: Pulmonata: Urocoptidae) from the eastern Cuban region. – Poeyana, 507: 40-43.

Cornu aspersum as pest

A brief paper by Ruiz-Galván et al. (2918) described how in Mexico a non-native population of Cornu aspersum (O.F. Müller, 1774) developed since 2013 into a pest on apple trees. Although the authors have not found a specific reason for this, their paper shows an effective counter-tactic.

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Reference:
Ruiz-Galván, I. et al., 2018. Helix aspersa (Stylommatophora: Helicidae) plaga emergente de la manzana (Malus spp.) en Guerrero, Chihuahua. – Acta Zoológica Mexicana (n.s.) 34: e3412161 (5 pp.).

New record for Gulella bicolor in Mexico

A specimen of Huttonella bicolor = Gulella bicolor (Hutton, 1834) was collected from clayey-sandy soil in Tabasco, Mexico, which constitutes its second record in the state and the third in Mexico. This small gastropod is a predator that has mainly spread through tropical and island regions as an exotic species. Its introduction to Asian and Caribbean Islands is noteworthy. Its pupiform shell and the lamella or tooth complex were compared against previous descriptions. In Mexico, this species has been found in northern Veracruz and Tabasco, which confirms that it is spreading along the Gulf of Mexico from the United States towards Brazil. The features of this streptaxid as a potential hazard through its preferred prey are discussed”.

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An additional record to the ones given in the paper is the recent mentioning of this species for Belize by Dourson et al. (2018: 315).

Introduced species are often problematic with regard to the native malacofauna, but in this case the authors argue that also additional reasons may be present for keeping a close eye on the further spread of this species. Which is related to exotic species always a good idea to follow and document their distribution.

Reference:
Costillo-Rodriguez, Z.G. et al., 2018. A new record of Huttonella bicolor (Hutton, 1834) (Mollusca, Gastropoda, Streptaxidae) in Mexico. – Acta Zoológica Mexicana (n.s.) 34: e3411181 (6 pp.).

New Bunnya species from Mexico

Mexican papers are plentiful this moment, but I am sure it is coincidental…

Just published, a paper by a mixed Mexican-Costa Rican author team, whose abstract reads as follows: “We describe a new helicoidean semi-slug based on morphological and molecular evidence. The new species belongs to the genus Bunnya and is described from a small agricultural area in Zinacantepec, San Juan de las Huertas, México. The genus Bunnya is externally similar to Xanthonyx, another Helicoidea genus; both genera have similar shell and body form, and both have a tail horn. Internally, Bunnya is similar to Humboldtiana, since both have dart-sacs (3 in Bunnya, 3−4 in Humboldtiana) surrounding the vagina, two dart-bulbs associated with each dart sac, and a gland number similar to the dart-sacs number. Four adult specimens of Bunnya metli n. sp. were dissected and compared with the two described species: B. bernardinae from Cuajimalpa, México City, and B. naranjoe from Sierra de Manantlan, Jalisco. Bunnya metli n. sp. is characterized by: very closely-spaced radial riblets (about 23 per mm) crossed by fine spiral wavy threads on the embryonic whorls; unfused glands inserted on the vagina above the dart-sacs and only one dart per sac; a short, swollen penis with a large spherical verge about half the penis size; an elongated bursa copulatrix with a slight constriction in the middle; a long bursa copulatrix duct; and dart sacs with a muscular pad within the vaginal lumen, surrounding the basal part of the genitalia. We performed a phylogenetic analyses using data from fragments of 16S rRNA mtDNA and 28S rRNA genes from one of the collected specimens, as well as other helicoidean sequences from GenBank. Our analyses support the membership of Bunnya metli n. sp. in Xanthonychidae. This suggests that the taxonomic position of Bunnya in Humboldtianidae or Xanthonychidae warrants reevaluation”.

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This appears to be a very well-executed study on this novelty, which also question the familiar placement of the species. No other Bunnya species have been sequenced, while only two taxa of the Xanthonychidae are currently included in GenBank. Further research may solve this situation.

Reference:
Araiza-Gómez, V. et al., 2019. A new species of the genus Bunnya H.B. Baker, 1942 (Helicoidea) from Mexico. – Malacologia, 62 (2): 237-246.