Monthly Archives: March 2012

Traveling in South America (4)

To conclude the pictures about Ecuadorian snails, two more species.

The first one is a Drymaeus species that Adri??n Gonz??lez observed in Maldonado, Prov. Carchi. During my trip we couldn’t find ones, but these pictures are proof of their existence.

Finally, when in Tandapi, we observed two Isomeria’s copulating. It was an interesting sight (unfortunately we didn’t film them), but we left the specimens in peace.

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DNA barcodes in Systrophia

A paper that appeared already last year is Pedro Romero’s study on Systrophia from Peruvian Amazonia (Romero & Ramirez, 2011). 

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DNA barcoding analysis is based on the comparison of genetic distances to identify species using a segment of Cytochrome C Oxidase I (COI) gene. Species identification through DNA barcoding challenges problems in groups with high genetic diversity as molluscs. Thus, our aim was to estimate intraspecific divergence in the Amazonian land snail Systrophia helicycloides (Gastropoda, Scolodontidae) and evaluate the use of DNA barcoding in molecular identification of this land snail. Nucleotide sequences were compared with Genbank and BOLD (Barcode of Life Data Systems) databases. We conducted distance analyses using the Neighbour Joining method. Systrophia helicycloides showed two groups of haplotypes and intraspecific genetic distances higher than 4%. We observed an overlap between intraspecifical and interspecific distances. The high divergence may be related to rapid mutation rate in the snail mitochondrial genome, to population distribution that influences genetic isolation and differentiation, and to ancestral DNA polymorphisms. COI profiles uploaded in BOLD are the first records of this species and can identify Systrophia helcycloides from other species. These profiles corroborated the high variation in the land snail genome. Therefore, species identification in this group needs a combined analysis of genetic distances, informative sites, and conventional taxonomy.
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Reference:
Romero, P. & R. Ramirez, 2011. Divergencia intraespecifica y codigo de barras de ADN en Systrophia helicycloides (Gastropoda, Scolodontidae). – Revista Peruana de Biologia 18(2): 201-208. 

ANSP 200

There is usually little room for institutional attention, as this blog is primarily focussed on snails. But on the CONCH-L list I just found an ode to the 200th birthday of the Academy of Natural Sciences in Philadelphia. The place where Henry A. Pilsbry (and his followers) served the (Neotropical) snails so well.

Thus, by exception, a copy of the ode made by Paul Callomon:

An Ode on the Occasion of the 200th Birthday of the Academy of Natural Sciences
21st March, 2012

Today’s the day
Two hundred years
Since a room full of guys
With beards to their ears
Set out to describe, to explore and chronicle
Nature in all, from mammoth to barnacle

Through war and perplexity
Guile and alliance
And flowering complexity
In natural science
They held to their mission
Unswerving, unfissioned

And so to today
When myriad stars
The whole of creation
And weird things in jars
Clap hands, fins and claws
In mighty applause

From Asia’s plains
To the Philippine strand
To the New Jersey swamps
A rubber-gloved hand
Reaches through muck
Through sand, leaves and slime
And gives us our compass
While there is yet time

Onward! Cry we, coffee cup firm in hand
Onward, our brave and hard-charging band
Raise high the banner
Our key word “Diversity!”
The ANSP
Of Drexel University

Very well done, Paul!

Biology of Omalonyx convexus

In a recent study, Arruda & Thom?? (2011) published the results of field studies on Omalonyx convexus (Heynemann, 1868) in southern Brazil.

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Their study reports that animals show a variation in their body coloration, and the number of specimens varied on sunny and cloudy days (resp. one specimen per 67 and 51 minutes collecting effort). The placement of the snails on habitat substrates varied according to the time of the day and the temperature.

The great variation of the body colour in different populations makes it difficult to use this characteristic for species delimitation, as has been done in the past for this group. The study provides also insight in the food of this species, which always consists of vegetal remains, but in a slight number of cases (6%) also pollen has been found and some instances where mites had been consumed (2%); the study presumes that living plants were eaten by Omalonyx convexus.
A study into the biological aspects of Neotropical snails that deserves imitation.

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Reference:
Arruda, J.O. & J.W. Thom??, 2011. Biological aspects of Omalonyx convexus (Mollusca, Gastropoda, Succineidae) from the Rio Grande do Sul State, Brazil. – Revista Biotemas 24: 95-101.

Little Cayman Cerion

Last year I had several posts here on Cerion from Little Cayman Island in the Caribbean. Lately, Pat Shipman and Alan Walker which have been mentioned before, found the only living Cerion nanus they could spot so far. They note that “the population – well, the habitat – is on the decline”; the local government is already studying captive breeding and re-introducing.

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New paper

Last week a new paper was published on the Weyrauch heritage. It contains a list of his taxa at the species level, partly a repeat of Barbosa et al. (2008) but with more exact data on his type localities. A list of taxa described by other authors based on Weyrauch’s material has been included. Finally, most of the Orthalicoidea type material present in the Tucum??n museum is here figured for the first time.

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References:
Barbosa, A.F., Delhey, V.K. & Coan, E.V., 2008. Molluscan names and malacological contributions by Wolfgang Karl Weyrauch (1907-1970) with a brief biography. – Malacologia 50: 265-277.
Breure, A.S.H., 2012. Weyrauch’s type localities: a clarification; with illustrations of types of Orthalicoidea (Mollusca, Gastropoda, Stylommatophora) in the Tucum??n museum. – Folia conchyliologica 17: 4-24.