Tag Archives: introduction

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.

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A snail with an U-loop

Cornu aspersum (O.F. Müller, 1774) is a common European snail with a ground colour of yellowish brown , and mostly with some darker spiral bands and irregular light and dark blotches (Jansen, 2015). Recently in a Dutch zoo a new tropical greenhouse was installed with plants imported from Costa Rica. Herman Creemers sent me a picture of snails collected in this greenhouse (on the right side), together with some specimens from the Netherlands (on the left side). He wondered if this species was known from Costa Rica or not.

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Barrientos (2003) has given an overview of Costa Rican species and said: “El escargot, Helix aspersa [the old name], fue introducido has más de 100 años y está restringido a jardines urbanos en San José”; the species is thus more than a century present in Costa Rica, but still restricted to gardens in the capital. The different coloration of shells presumably originating from Costa Rica, imported together with plants, is somewhat different. This might be due to the prolonged isolation, but only detailed DNA research could tell whether some divergence has occurred or not.

References:
Barrientos, Z., 2003. Estado actual del conocimiento y la conservación de los moluscos continetales de Costa Rica. – Revista de Biologia Tropical 51, Supplemento 3: 285–292.
Jansen, A.W., 2015. Veldgis slakken en mossels. Zeist, KNNV, 272 pp.

Bulimulus as world travelers

Some Bulimulus species can act as alien species, as has been reported here extensively with introductions in Florida (B. guadalupensis, B. aff. sporadicus), Costa Rica and Ecuador (both B. guadalupensis). As recent research has shown (Breure 2016 PeerJ in press), DNA can help to reveal the likely source of origin. However, this is only possible if there is sufficient reference data available, i.e. sequences from specimens adequately identified with good locality data.

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Recently, a Bulimulus species was detected on containers originating from India, Thailand, southern China and Singapore in the port of Darwin, north Australia. Initially confused with a Cerastid species, several people now agree that it is likely a Bulimulid. However, which species? There is now speculation it is a species from Brazil or Argentina, which would place it in the Bulimulus sporadicus species-complex, extending from northern Argentina (B. bonariensis), Paraguay, Bolivia into southern Brazil. This species complex is insufficiently known, its morphological variation within its distribution is ill-documented, and with only one sequence from Paraguay as reference material the hope for a quick fix of this hitch-hiking snail is in vain. So before we might be able to solve this issue, the first action is to collect living specimens throughout the distribution range and sequence them. Work for local malacologists or a student in need for an interesting and an useful topic! Any takers?

Luckily, Bulimulus species can only be a nuisance, so far I have never heard of any real damage to the local fauna and flora.

New record of Polygyra from Guadeloupe

The introduction of Polygyra cereolus (Megerle von Mühlfeldt, 1816) on Guadeloupe is recorded in a paper by Laurent Charles (2014). The material was collected in 2013, but may have occurred already for some time on the island; new introductions in a fauna may remain unnoticed if the species is relatively small.

Charles2014

Reference:
Charles, L., 2014. Signalement de Polygyra cereolus (Megerle von Mühlfeldt, 1816)(Mollusca: Gastropoda: Polygyridae) à la Guadeloupe (Petites-Antilles). – MalaCo 10: 5-6. (Available at http://www.journal-malaco.fr/documents/MalaCo_2014_10_Charles_5_6.pdf)