Monthly Archives: February 2011

Photo of the day (117): Kara

Modest Correoso kindly sent me several pictures of what I now call Kara thompsonii (Pfeiffer, 1845); previously this was considered as Thaumastus (Kara), but the evidence to raise this subgenus to generic status will be published later.

These specimens were observed in Ecuador, Prov. Loja, Vilcabamba and show a remarkable colour variation, both in the shells and in the colour of the animal. The dark form corresponds to nigricans Cousin, 1887; the yellowish form to olivecea Cousin, 1887. Both forms are now considered as colour variations only and fall in the synonymy of K. thompsonii.

The dark form tends to be somewhat more elongate and more slender, but Modest found them in a mixed population. The locality was approx. 1675m, vegetation type “Bosque seco” with Cerotonia siliqua and Opuntia.

New data on Santa Catarina, Brazil

Two new papers on Brazilian land snails from Santa Catarina State were just published by Ignacio Agudo In Ellipsaria (http://molluskconservation.org/EVENTS/ELLIPSARIA/EllipsariaMarch2011.pdf). One deals with the occurrence of Omalonyx (p. 19-20), the other (p. 20-26) is an update on a checklist of the continental and marine molluscs of Santa Catarina. 

 

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History matters

During revisions, old collections may pose questions totally unrelated to taxonomy, which are nevertheless crucial to solve in order take the right decision. An example may illustrate this.

 

In the Natural History Museum in London I found material of Bostryx guttatus (Broderip, 1832), which was described from “Peruvia, Cobija or Puerto de la Mar”. Nowadays, Cobija is considered Chile, Región de Antofagasta.

 

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In the collection, this material was labelled ‘Bolivia’, and the question was: could these specimens possibly be considered syntypes, even if they were seemingly mislabeled?

 

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For an answer to this question we have to know some facts about the history of this region. In Spanish times this region was part of the Audencia of Charcas, which was a political units of the Viceroyalty of Peru. It was bordered in the south by the Audencia de Chile.

 

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Chile became independent in 1818, and Bolivia (till then called ‘Upper Peru’) followed in 1825. Bolivian and Chilean historicans disagree on whether there was access to the sea for this new republic. During the 19th century borders were often not well defined and boundaries in the Atacama had not been well-established when deposits of nitrate, silver and copper were discovered. The dispute began when both countries claimed the territory, leading to the War of the Pacific (1879-1884).
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It ultimately led to the Chilean annexation of the Tarapacá department and Arica province and of the Bolivian department of Litoral; it left Bolivia as a land-locked country. Later the boundary between Chile and Peru was established with the Tacna-Arica compromise in 1929.

 

The conclusion thus may be, that any material that was collected in this region during the 19th century could bear a label indicating one of the three countries involved, depending on the exact date of labeling. Note that this labeling also could have been done at a later stage, with re-interpretation of the political-administrative situation. Thus some margin of error may always be involved, unless there other sources which are helpful for the interpretation.
My answer to the question of the B. guttatus label is, yes it may be possible to interpret this as a case where ‘Bolivia’ was correct at the time of labeling, where the locality of collection now belongs to Chile.

 

Source: http://en.wikipedia.org/wiki/Atacama_border_dispute with related links and references quoted therein.

Fieldwork Peru (4)

Marjan van Hulsel, the student doing fieldwork now in Peru on carinated shells, has started in the second region. She is located in Tembladera, Dept. Cajamarca.

On her second day, she made an interesting observation. With two taxa of Scutalus known from the region, S. cretaceus and S. baroni, she found a transition between the two species. This was expected already, based on shells collected in the 1950s by Wolfgang Weyrauch (in the Tucum??n museum). However, it was not known where this transition zone was located and how extended is was. Marjan observed a transition that extended only a few meters.
Obviously, we have now a good starting point for further investigation.

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Multitude of shells

As a sequel to the previous post on Bostryx, today a picture that I took last year at Lomas de Atocongo, near Lima, Peru. As you may see, many, many shells; no living specimens were found here, but they hide in the vegetation covered parts of the lomas where they hibernate during most of the year. The shells must have been blown by the wind into this desert-like part and accumulated over time.

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Converting coordinates

On the Taxacom List there was today an overview of tools to convert coordinates, either individual or in batch. Just passing through this here…

Converting GPS coordinates: easy online services and programs.
Individual locations: basically copy paste the input and copy/paste the output
– The FCC site. Online available: http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
– SpeciesLink converter. Online available only: http://splink.cria.org.br/conversor?&setlang=en
– OASIS UTM Conversion. Online available: http://www.oasisphoto.com/navigation/convert_form.php
– ACME mapper. Online available: http://mapper.acme.com/
Batch conversion: copy/paste batches or open input files and save output files
– LOTE Geographical Projection Conversion. Download freeware program from http://gcmd.nasa.gov/records/ESS_LOTE.html
– Spreadsheet UTM conversion tool. Free download on http://www.uwgb.edu/dutchs/usefuldata/howuseexcel.htm
– FRANSON CoordTrans. Download free 7 days trial from http://franson.com/coordtrans/
More advanced programs
– Global Mapper
– Mapinfo
– ArcMap of ArcGIS
– GDAL(Warp) downloadable on http://www.gdal.org/
– Geotrans 3.1 available on: http://earth-info.nga.mil/GandG/geotrans/
– Corpscom 6.0 available on http://crunch.tec.army.mil/software/corpscon/corpscon.html
– R package PBSmapping has a function convUL

Photo of the day (116): Bostryx

Today some pictures of living specimens of Bostryx reentsi (Philippi, 1851). This species was described from “near Chala” in Dept. Arequipa, Peru. Several years ago I received a subfossil shell from B. Verdcourt, which had been collected by O. Whaley amidst a Nazca Culture midden on an archaeological site near Ullujaya, Dept. Ica (reported in my 2008 paper on carination, http://www.repository.naturalis.nl/document/122256). This site is approx. 200 km further north from Chala along the coast, without known localities in between.

This week I received an email from Oliver Whaley with the first pictures for this species of live snails. Oliver writes: “[This] huge pre-columbian midden consisting entirely of snails […] On top I found several alive”. 
He also notes “The disjunct nature of the populations is interesting in terms of dispersal and the comparison we have of the plants between the two areas”. 

Thanks Oliver for digging up these interesting pictures!

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Phylogenetic methods

When reading through the phylogenetic literature, a split may be observed between those who favour maximum likelihood and those who consider Bayesian methods superior. Of course, a number of paper used mixed methods, but usual there is a tendency to either side.

Having seen that in Geneious now PhyML has several options, I looked up the PhyML website for some details. The options with which you can run PhyML are a) the well-known bootstrap, b) the approximate likelihood test (aLRT), c) aLRT with parametric branch support using Chi2, d) aLRT non-parametric branch support based on Shimodaira-Hasegawa-like procedure. See http://www.atgc-montpellier.fr/phyml/alrt/ for more details. There is also data on a benchmark comparing the options:
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Interesting enough, in their paper describing the aLRT statistic, Anisimova & Gascuel (2006) present a figure which clearly shows the comparison with simulated data sets. This allows for a theoretical ‘fair-play’.
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Although I am applying different methods on the same empirical data set, I always had the impression that the Bayesian method as implemented in BEAST. I feel a little more confident now, but one should always be open for the ‘Popperian black swans’. Science is all about skepticism…

Reference:
Anisimova, M. & Gascuel, O., 2006. Approximate likelihood ratio test for branches: a fast, accurate and powerful alternative. – Systematic Biology 55: 539-552.

New zoological names

The formation of new names in zoology is regulated by the International Code of Zoological Nomenclature (ICZN). This happened to be a book (my 1964 edition counted 176 pages!), but may now be found online at http://iczn.org/code. However, finding your way in the many Articles, Recommendations, and Opinions is not an easy task for someone who wants to describe a new taxon.Mike Taylor has taken the initiative to make an excerpt of the main points from the Code, and the best pratices, to be followed when describing a new animal. His checklist may be found here: http://svpow.wordpress.com/checklist-for-new-zoological-genus-and-species-nam…. The intention is to extend this checklist for names above the genus level.