Willem Heijns wrote:ust out of curiosity: what is a natural group sensu Morgenstern?
A natural group would then simply require that the included populations (or taxa, if higher categories are concerned) are "naturally" (that is by natural reproduction) descended from a common ansestor, but it would not necessarily have to contain all of them.
Willem Heijns wrote:With regard to the Barombi Mbo fauna: how do we know that the population of S. galileus galileus you mention is the ancestor of the species flock in this craterlake? Or could it have been a "galileus-type" fish?
Of course nobody was there when the lake was formed and colonized by fishes. However, in the example scenario, the assumption that it was a "galilaeus-type" fish would make S. galilaeus
(the trinomen was an error of mine, though the most closely related population referred by Schliewen would be referrable to the subspecies galilaeus
according to Trewavas 1983) even polyphyletic. And even if galilaeus
was split into several 'cryptic' species, the para- or polyphyly of the genus Sarotherodon
I fully concur with Patrick's view that cladistics should be seen as not more, but also not less, than an useful tool.
cichla wrote:And yes, in the strict sense of Hennig's phylogenetic systematic the ancestor species has to be re-named if a part of it developed to a new species. This is why I think - at least at species level - it is not applicable.
I agree, and - with regard to the implications on binominal nomenclature - I would even extend this to genus level. Remember that the Linnean nomenclature was not intended as an end in itself, but as a practical reference system. And this, I fear, is getting lost by recognizing taxa only if they are monophyletic clades.
Willem Heijns wrote:And finally about synonyms: ICZN art. 50.1 says: "the author of a name is the person who first publishes it" In our case: if Heros melanurus GÜNTHER 1862 is synonymized with Paraneetroplus melanurus, which author and date should be fixed for the latter name?
Of course I know this was a rhetorical question, let's nevertheless look what the Code says:
50.3.2. Change in generic combination of a species-group name does not affect its authorship (see Article 51.3 for the use of parentheses to indicate changed combinations).
51.3. Use of parentheses around authors' names (and dates) in changed combinations. When a species-group name is combined with a generic name other than the original one, the name of the author of the species-group name, if cited, is to be enclosed in parentheses (the date, if cited, is to be enclosed within the same parentheses).
It's Paraneetroplus melanurus
There are several ways to cite additionally the author of a new combination, one is suggusted in the Code:
Recommendation 51G. Citation of person making new combination. If it is desired to cite both the author of a species-group nominal taxon and the person who first transferred it to another genus, the name of the person forming the new combination should follow the parentheses that enclose the name of the author of the species-group name (and the date, if cited; see Recommendation 22A.3).
Other methods include separation of species name and author by comma, semicolon or colon, or adding "new combination" etc.
However, this all is of minor importance, see article 51.1 (emphasis by myself):
51.1. Optional use of names of authors. The name of the author does not form part of the name of a taxon and its citation is optional, although customary and often advisable.
To bring back the discussion from philosophical matters and terminology to the actual topic of the MCMahan paper:
Though fully convinced of the identity of the species, I'm nevertheless somewhat surprised that nobody here advocates for their distinctness, since until a few days ago both synspilus
(generic names deliberately omitted to avoid confusion) were maintained.
Finally, I find Juan Miguel's consideration to apply the results from McMahan & al. to Thorichthys affinis
and T. meeki
absolutely worthy to be discussed in this context. The distributional pattern and habitat preferences are comperable (except for the more extended range of Thorichthys
in Northern Yucatán) and the two forms are indeed more similar to each other than each of them to other species of the genus. However, in several relatively recent works dealing with the species level taxonomy of Thorichthys
(i.e. Rivas 1962, Hasse 1981, Miller & Taylor 1984 and Miller 2006) they are recognized as distinct on the basis of comprehensive material. Therefore they should not be synonymized without a careful study of intraspecific variability.