Tag Archives: helicinidae

New Cuban species

A while ago (December 2017) Espinosa et al. published a paper which only now surfaced. Its abstract is extremely short, even not mentioning the names of the new species they described. “A commented and illustrated catalog of 37 land an freshwater mollusks species from Cupeyal del Norte, Alejandro de Humboldt National Park, Guantánamo, Cuba, is presented, 18 of them are new records to the park and 8 are described as new species, and data’s about others land mollusks species of the Park are included”.

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The new taxa introduced are:

[Helicinidae:] Emoda poeyana

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[Annulariidae:] Diplopoma (Subannularia) mucaralense

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Annularisca (Annularella) haylerae

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[Urocoptidae:] Arangia humboldtiana

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Carcinostemma silvai

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[Achatinidae:] Obeliscus (Stenogyra) diegoi

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[Cepolidae:] Coryda thierryi

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Coryda carabelloi

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Reference:
Espinosa J., Herrera-Uría J. & Ortea J., 2017. Moluscos terrestres y fluviales del Sector Cupeyal del Norte, Parque Nacional Alejandro de Humboldt, Guantánamo, Cuba, con la descripción de nuevas especies. – Revista de la Academia Canaria de Ciencias, 29: 61-110.

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New records for Brazilian Helicina

A new paper just appeared by Silva et al. “New records for Helicina schereri Baker, 1913, are reported. It was a species previously restricted to the states of Ceará, Rio Grande do Norte, Paraíba, Alagoas and Tocantins in Northeastern Brazil, and State of Santa Catarina, much further south. The new occurrences reported herein fill distribution gaps and also significantly expand the range of the species ca. 970 km westwards. The new records are from the following locations: Bahia State (Ituaçu and Itaquara municipalities) in Northeast Brazil; Mato Grosso do Sul State (Bonito Municipality) in the Midwest; and Minas Gerais (Lagoa Santa municipality) in the Southeast”.

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Reference:
Silva, F. dos Santos et al., 2019. New records of Helicina schereri (Gastropoda: Helicinidae) from the states of Bahia, Minas Gerais, and Mato Grosso do Sul, Brazil. – Papéis Avulsos de Zoologia, 59: e20195903 (3 pp.).

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. 

Brazilian Helicina

Freshly pressed: a paper by Silva et al. on Brazilian Helicina. Their abstract reads as follows “New records for Helicina schereri Baker, 1913, are reported. It was a species previously restricted to the states of Ceará, Rio Grande do Norte, Paraíba, Alagoas and Tocantins in Northeastern Brazil, and State of Santa Catarina, much further south. The new occurrences reported herein fill distribution gaps and also significantly expand the range of the species ca. 970 km westwards. The new records are from the following locations: Bahia State (Ituaçu and Itaquara municipalities) in Northeast Brazil; Mato Grosso do Sul State (Bonito Municipality) in the Midwest; and Minas Gerais (Lagoa Santa municipality) in the Southeast”.

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Reference:
Silva, F.S. et al., 2019. New records of Helicina schereri (Gastropoda: Helicinidae) from the states of Bahia, Minas Gerais, and Mato Grosso do Sul, Brazil. – Papéis Avulsos de Zoologia, 59: e20195903 (4 pp.).

Predation by fireflies

Sometimes one need to consult obscure papers in related disciplines to find some data on predation of molluscs. Recently a paper was published by Madruga (2018), reporting “a multiple-choice feeding-preference experiment was made to test the feeding behaviour of the larvae of Alecton discoidalis Laporte, 1833, a Cuban endemic firefly. It was found that in 60% of cases the larvae preferred to feed on Praticolella griseola (Pfeiffer, 1841), an introduced species of snail, considered a farming pest. Therefore, these lampyrid larvae seem to be a natural predator of this snail, which could be considered as a biological agent for pest control of the snail”.

As this paper was not readily available to me, I searched for it and by serendipity found an older one with additional data (Madruga & Hernández, 2010): “Alecton Laporte, 1833, with four known species is the only firefly genus endemic to Cuba. Alecton discoidalis Laporte, 1833, is its most common species, distributed in the western half of the country. Unfortunately, much of its life history remains unknown, as with the rest of Cuban representatives of the family Lampyridae. Larvae are associated with adults of A. discoidalis through rearing, and observations on larval feeding habits of this species are presented. Thirteen species belonging to seven gastropod families are reported for the first time as prey of A. discoidalis larvae. Our data suggest that these are generalist predators of terrestrial snails. A remarkably close association exists between this lampyrid and operculate species of snails. The later represents the most abundant and diverse group of molluscs in limestone landscapes, where the beetles are commonly found”.

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References:
Madruga, O., 2018. Seleccion alimentaria de las larvas de la luciernaga cubana Alecton
discoidalis (Coleoptera: Lampyridae). – Boletin de la Sociedad Entomológica Aragonesa, 62: 321-322.
Madruga, O. & Hernández, M., 2010. Larval Feeding Habits of the Cuban Endemic Firefly Alecton discoidalis Laporte (Coleoptera: Lampyridae). – Psyche (2010): e149879 (5 pp.).

 

Helicina: anatomical data

Luiz Simone just published a paper on the anatomy of Helicina variabilis, a typical member of the family Helicinidae, which occurs in Brazil.

Helicina variabilis Wagner, 1827 (Neritimorpha, Helicinidae) is redescribed based on a sample collected in Nanuque, northern Minas Gerais, Brazil. The species description, previously based only on the shell, is expanded to the phenotypic features. The study revealed absorption of the internal shell whorls; a diaphragm muscle connected to the floor of the pallial cavity; a monoaulic pallial oviduct, with the female genital aperture inside the anal aperture, and the lack of a seminal receptacle and provaginal sac; and the pleural ganglia of the nerve ring connected with each other. The significance of these findings is discussed in the light of current taxonomic and phylogenetic knowledge”.

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In the discussion of the paper Simone highlights the features that are interesting for the taxonomy of the group. The bursa copulatrix has a branched structure which may be useful in distinguishing different species. Comparisons are being made to related groups such as the Neritidae and to recent studies on the higher systematics of these groups. All in all an excellent paper, especially by the nicely detailed anatomical figures.

Reference:
Simone, L.R.L., 2018. Phenotypic features of Helicina variabilis (Gastropoda: Neritimorpha) from Minas Gerais, Brazil. – Papéis Avulsos de Zoologia, 58: e20185832 (9 pp.). http://doi.org/10.11606/1807-0202/2018.58.32

Galapagos micromolluscs

An interesting paper was recently published by Miquel & Bungartz on micromolluscs found among Galapagos lichens and bryophytes, including a new species.

The new species is a carnivorous snail, Scolodonta rinae, and this family is reported for the firt time from the Galapagos. Other species that were encountered are Pupisoma galapagorum, P. dioscoricola, Tornatellides chathamensis, Helicina sp., and Succinea sp.

The new species was found on the island of Santa Cruz.

Reference:
Miquel, S.E. & Bungartz, F., 2017. Snails found among herbarium specimens of Galapagos lichens and bryophytes, with the description of Scolodonta rinae (Gastropoda: Scolodontidae), a new species of carnivorous micro-mollusk. – Archiv für Molluskenkunde, 146 (1): 173-186.