Monthly Archives: August 2017

Geometric morphometric study on Cuban Cerion

Recently a study by Jonathan Miller came to my attention about Cuban Cerion species. Morphometric studies are becoming more popular, but the methodology may not be familiar to the readers and can be challenging to perform.

The abstract reads: “Cerion mumia is a complex of eight subspecies distributed along the north coast of Cuba from Pinar del Rio to Camaguey provinces. The geometric morphometric analysis presented here was aimed at identifying patterns of shell shape variation to test the hypothesis of colonisation through land bridges during the Eocene-Oligocene. C. mumia cuspidatum, the easternmost population, was similar in shape to the subspecies from the north coast of Havana, but showed morphometric differences suggesting allopatric speciation followed by dispersal. The shells from the west were more globose than those from Havana or the east, which tended to be more cylindrical, as shown by the thin-plate spline analysis. As a result of the morphometric analysis I propose to elevate C. noriae comb. nov. and C. wrighti comb. nov. to species rank and to include C. noriae hondanum comb. nov. as a subspecies of C. noriae comb. nov. I report a second locality of C. noriae comb. nov. at Playa Santa Fe formation from the late upper Pleistocene. Geometric morphometric techniques are useful in species identification through comparing new samples with type material”.

The author collected his shells in the field, photographed them in situ and released them afterwards. Therefore, as far as I understand, no vouchers are available in a museum collection of the material studied. This might be a challenging procedure and may hamper the repeatability of this study. Otherwise this seems a nice study with as outcome that this species group may be split into three species with disjunct distribution along the Cuban north coast.

Reference:
Miller, J.P., 2016. Geometric morphometric analysis of the shell of Cerion mumia (Pulmonata: Cerionidae) and related species. – Folia Malacologica, 24: 239-250.

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Cecilioides in Argentina

Diaz et al. recently published a new record of an introduced species for Argentina. “Cecilioides acicula (Müller, 1774), family Ferussaciidae, is native to the Palaearctic region but has been dispersed around the word by human activity. Here, we report the presence of this introduced species in La Plata city, Buenos Aires province, Argentina. This snail is largely subterranean and frequently is found in old graves in association with skeletal remains. Our samples were collected from sediments from the Municipal Cemetery of La Plata, Buenos Aires province, Argentina”.

Reference:
Diaz, A.C. et al., 2017. First record of Cecilioides acicula (Müller, 1774) (Mollusca: Ferussaciidae), from Buenos Aires province, Argentina. – CheckList, 13(2): 2096.

Predation by land planarians

Land planarians are increasingly been reported as predators of land snails, and several reports have been summarised by Cseh et al. (2017), as well as presenting new data.

“The food preference of Obama anthropophila Amaral, Leal-Zanchet & Carbayo, 2015, a species that seems to be spreading across Brazil’s human-modified environments, was investigated. Extensive experiments led to the conclusion that the generalized diet of this species may have facilitated its dispersal. The analysis of 132 feeding records of 44 geoplaninid species revealed a tendency for closely related species to feed on individuals from similar taxonomic groups, suggesting that in this group behavioral evolution is more conserved than phylogenetic diversification”.

The paper supplies a table with the known prey animals of land planarians.

Reference:
Cseh, A. et al., 2017. Observations on food preference of Neotropical land planarians (Platyhelminthes), with emphasis on Obama anthropophila, and their phylogenetic diversification. – Zoologia (Curitiba), 34:e12622