Comments on the proposed conservation of usage of Testudo gigantea Schweigger, 1812 (currently Geochelone (Aldabrachelys) gigantea; Reptilia, Testudines) 4

Publication Type:Journal Article
Year of Publication:2009
Authors:E. N. Arnold
Journal:Bulletin of Zoological Nomenclature
Start Page:177
Date Published:06/2009
Type of Article:Comment
Full Text

As someone with a long involvement with Indian Ocean reptiles, I
support the proposal of J. Frazier to conserve the species name of the
Aldabra tortoise as gigantea and accept the designation of a
neotype. The present instability, where three species names have
recently been used for this species, has many deleterious effects. 1.
Scientific nomenclature is brought into disrepute, to the extent that
some people have simply abandoned it in the present case and use
vernaculars instead. ‘Aldabra tortoise’ is presently more certain in
its meaning and ad hoc status than the competing scientific names, and
avoids conflicts and uncertainties about which of these to use. 2. Name
instability is bad for conservation of the species concerned. Most,
perhaps all, international and national protective legislation uses the
species name gigantea for the Aldabra tortoise. Any
uncertainty about its meaning risks depriving the species of some of
its legal protection. 3. Protracted disputes over scientific names such
as the present one take up significant amounts of time that would have
been more usefully spent on studying and conserving the animals
concerned (witness the numerous published papers, comments and
petitions in the present case). While arguing at length about
nomenclatorial problems has all the appearances of scholarship it does
not advance our knowledge of the natural world. The name gigantea is
by far the most commonly used and understood for the species, and the
one which elicits nearly all the biological information about it when
searching databases etc. Consequently, fixing the name gigantea for
the Aldabra tortoise would help the very large audience of
non-taxonomists, most of whom already use the name. It is the needs of
these biologists, conservationists, legislators and hobbyists that
should be addressed in the present case. What the much smaller number
of taxonomists might prefer is far less important, especially as they
are used to synonyms. Nomenclature should not merely be a playground
for specialists but should address the needs of the majority of users.
If the species name gigantea is not fixed for the Aldabra
tortoise, instability is likely to persist, as some specialists are
unlikely to accept the alternative interpretation, that Schweigger’s
original description of Testudo gigantea really refers to a
South American species. The scientific literature of the last twenty
years or so shows that the description is open to radically different
interpretations. While the case for the recent discovery of the actual
type of T. gigantea may be credible, by no means everyone involved believes that it is certain. Fixing gigantea as the name of the Aldabra tortoise would also harmonise the case for using the generic name Aldabrachelys Loveridge and Williams, 1957 for it. The authors clearly intended Aldabrachelys to refer to the Aldabra tortoise and its relatives and clearly believed that the type species of the genus, named as Testudo gigantea, was this taxon. Alternative identifications of Schweigger’s T. gigantea resulted in the creation of the more recent alternative generic name Dipsochelys which is presently used alongside Aldabrachelys (and also Geochelone!) adding to the multiplicity of combinations used for the Aldabra tortoise and the subsequent nomenclatorial confusion.

Taxonomic Group(s): 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith