The Cornu Problem

The Cornu Problem The example of the brown garden snail (Cornu aspersum) shows in a fine way, how a snail species name has developed over the centuries since it has first been founded, how systematic names are distributed, and that there are sometimes exceptions. For the first time, the species was described as Helix aspersa in "Vermium Terrestrium et Fluviatilium seu animalium infusorium, helminthicorum, et testaceorum non marinorum succincta historia" by the Danish naturalist Otto Friedrich Müller (1730-1784). Helix aspersa literally means "spotted snail" in Latin. Müller's book also was special, because he not only provided important basics to the science of snails, but also for the first time tried to systematically describe microorganisms ("infusoria"). In Vienna, in the year 1778, Ignaz von Born (1742-1791) published the results of an imperial order to put a system into the nature collections of the imperial court museum: "Index rerum naturalium Musei Caesarei Vindobonensis". In this book, he published an image of a misshapen brown garden snail as Cornu copiae (the fillhorn). Ignaz von Born was also a very interesting person himself: A freemason, he was a contemporary of Mozart (probably the person, on who is based the sage Sarastro from the Magic Flute). He is better known for numerous publications and inventions in the field of mineralogy. A further systematic name the garden snail received in 1837 by Jean de Charpentier in "Catalogue des mollusques terrestres et fluviatiles de la Suisse". There it was called Cryptomphalus aspersus. Cryptomphalus in Greek means "hidden navel", referring to the shell navel or umbilicus, that cannot be seen in the garden snail, because it is hidden behind the columellar part of the apertural lip (Picture left). The modern systematics of the brown garden snail shows two views, to a certain extent competitive, of how the snail should be named correctly. In contrary to that GIUSTI et al. 1996 in their book "The non-marine molluscs of the Maltese Islands" place the brown garden snail and the grunt snail Cantareus apertus (BORN 1778) in one genus common to both: Cantareus RISSO 1826. In particular, the genus Cornu is said to be invalid, because the specimen described by von Born was misshapen. Misshapen or teratological shells, as stated by the ICZN (International Commission on Zoological Nomenclature), however, are not valid as basis for a systematical name (Chapter 1, Art. 1, 1.3 Exceptions, 1.3.2: "for teratological specimens as such"). On the other hand, in a review of the book, J. GERBER writes in 2000 in the magazine Heldia 3/1 (pp 42 ff.): "If "Helix" aspersa" should be placed in one genus with "Helix" aperta, as was done by the authors on the basis of genital anatomy, will have to stand further examination. Using the genus name Cantareus RISSO 1826, though, appears problematic. As it is not proven, that Born used the name of Cornu copiae in 1778 under the conscience and with the intent do describe a teratological specimen, ICZN (see above) does not apply and Cornu thus is an available genus name.". As a summary, Giusti's placing Cornu and Cantareus in one common genus Cantareus is not accepted by the majority of malacologists. Additionally the genus CornuBORN 1778 is understood as available, because it was not explicitly stated Cornu copiae was meant to be the misshapen specimen in contrary to the snail species as such. The result now is, that some malacologists stick with the name Cantareus aspersus according to GIUSTI, others remaining with Cornu aspersum according to CLECOM. The present homepage at hand will, as mentioned in the preface, continue staying with CLECOM. ************************************************* To read more visit http://www.biostim.com.au/sustainable-agriculture.html.

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