Tag Archives: drymaeus

Photo of the day (180): Drymaeus

05 Drymaes - foto Fred

Another photo of Drymaeus elongatus (Röding, 1798) from Curacao. Thanks to the group of explorers that almost weekly visit a part of the island, regularly a snail (usually in dormancy like this one) turns up in the photo reports. This picture was made by Fred Chumaceiro during a visit to Rooi Katoen.

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New Drymaeus from Peru

Just published: a paper on Peruvian Drymaeus species with description of a new species by Mogollón & Breure.

The abstract reads: “Critical remarks are made on Drymaeus species, reported from Peru in a study on land snails from National Parks at the eastern side of the Andes. Four of these species (Dry­maeus multilineatus, D. coniformis, D. glaucostomus, all known from Venezuela or Central America, and D. geomet­ricus, known from Colombia) appear to be misidentified as Peruvian species, which thus may lead to incorrect biogeographical interpretations. Correct identifications are given for all the disputed Drymaeus species. Bulimulus (Bulimu­lus) inconspicuus F. Haas, 1949, is now transferred to Dry­maeus (Mesembrinus). Additionaly, a new species, Drymae­us (Drymaeus) verecundus Breure & Mogollón, is described”.

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The new species was found near Iquitos in NE Peru, and the type material has been deposited in the Brussels and Leiden museums.

Reference:
Mogollón, V. & Breure, A.S.H., 2019. Notes on Drymaeus species from Peru (Mollusca, Gastropoda, Bulimulidae), and description of a new species. – Basteria, 83: 13-18.

New Brazilian species

Recently published, Simone & Do Amaral studied snails collected on islands off the Brazilian coast and discovered new species.

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Their abstracts is as follows: “Three new species of Bulimulidae (Gastropoda, Pulmonata) are described, each one endemic to a different island off the São Paulo coast, showing a high degree of endemicity of these islands in terrestrial malacofauna. Drymaeus castilhensis occurs on Castilho Island, it is mainly characterised by the strong axial dark spots in the shell or in being totally pale beige, penis elongated, lacking any inner chambers or glands, and double ducts of albumen gland. Drymaeus micropyrus occurs on Queimada Pequena Island, it is mainly characterised by greenish-cream shell, with narrow axial spots, and single duct of albumen gland. Bulimulus sula is from Alcatrazes Island, its main features include a relatively cylindrical, featureless shell, bilobed penis and, mainly and remarkably, a genital appendix that looks like a small accessory penis. These three species are described and compared with similar species, and accounts on their biogeography”.

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The two species of Drymaeus, if presented as shells only and without locality data, are so similar that would have doubted them to be two different taxa. But the anatomical differences evidently show that cannot be conspecific. Also the Bulimulus species is anatomically peculiar with the reported “small accessory penis”.

Reference:
Simone, L.R.L. & Amaral, V.S. do, 2018. Insular life: new endemic species from São Paulo oceanic islands, Brazil (Pulmonata, Bulimulidae), as example of endemicity. – Journal of Conchology, 43(2): 167-187.

Photo of the day (173): Drymaeus

The group ‘Speurneuzen’ makes nearly every week a hike on the Island of Curaçao, usually to look for cultural-historical objects, but always to enjoy nature. This week they followed a new trail made by ‘Uniek Curaçao’ from Fort Kloof to Ascuncion. From their photo report I show a small batch of Drymaeus elongatus on a Wayaca tree.

The picture was made by Fred Chumaceiro.

Drymaeus tripictus ecology

Zaidett Barrientos have made an important contribution to the ecology of Neotropical snails to study the ecology and biology of Drymaeus tripictus (Albers, 1857) in Costa Rica. The abstract of the recent paper is as follows: “Very little is known about the ecology and biology of Drymaeus tripictus, an extremely rare and endemic land snail species from Costa Rican highlands. I studied the ecology and reproductive biology of D. tripictus from April 2009 through June 2010 in an old forest, a young forest and a Cupressus lusitanica plantation in central Costa Rica. Every three months I visited each habitat and collected specimens in 20 random sampling plots (3×3 m2 each). I observed the snail’s activity and microhabitat preference in the field, and in the labora- tory I recorded high definition videos of its mating behavior and analyzed reproductive morphology with light microscopy. The snail is more abundant in the old forest (0.017 ind./m2) and prefers leaves with little epiphyllous cover (0-25 % cover, chi-square test, p <0.0001). During the dry season the snails become active between 20:00 pm and 8:00 am (chi-square = 22.65, df=3, p < 0.0001); they are inactive mainly during the afternoon (11:00 am to 16:59 pm). I found active individuals mostly on the upper side of leaves, where they feed (Chi-square =6.76, df=1, p = 0.0093). Mating is unilateral, by shell mounting, with cryptic phallus intromission and without role switching or multiple mating. Its reproductive system is morphologically similar to that of Drymaeus costaricensis. Mating behavior is as expected for snails with high-spired shells, except for the lack of role switching. The density of D. tripictus is low even when compared with other endangered bulimulids”.

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A very interesting paper, which I had the pleasure to review as a draft (although not acknowledged).

Reference:
Barrientos, Z., 2016. Reproductive system, mating behavior and basic ecology of an extremely rare tropical snail: Drymaeus tripictus (Stylommatophora: Bulimulidae). – Revista de Biología Tropical, 64(1): 55–68.

Bulimulids introduced in the Pacific

Carl Christensen kindly sent me two papers which testify that two members of the Bulimulidae have been introduced to Pacific Islands.

The first one is an inventory of introductions in the Hawaiian Islands (Hayes et al., 2012). Bulimulus guadalupensis is reported from one of the islands.

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“This species originated in the Caribbean, where it is widespread, especially in disturbed habitats. It has been introduced to Florida, probably in association with agricultural or horticultural plants, and has been recorded in abundance in lawns and among ornamental plants in a residential area, as was the present material. It is likely that it was introduced via the horticultural trade. The only two localities at which the species has been found in the Hawaiian islands were close together and were also the only two localities at which Vallonia pulchella was found”.

In the second paper the occurrence of Drymaeus multilineatus (Say, 1825) is recorded on the island of Guam. According to Christensen, this species was introduced on that island before 1978, “likely inadvertently with cultivated plants” (Kerr & Bauman, 2013).

References:
Hayes, K.H., Yeung, N.W., Kim, J.R. & Cowie, R.H., 2012. New records of alien Gastropoda in the Hawaiian Islands: 1996-2010. – Bishop Museum Occasional Papers, 112: 21-28.
Kerr, A.M. & Bauman, S., 2013. Annotated checklist of the land snails of Mariana Islands, Micronesia. – University of Guam Marine Laboratory Technical Report, 148: i-vii, 1-72.