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Re: New papers in Geobios (and nomenclatoral gripe)

Tim Williams wrote-

If the species in question is the type species for a genus, then that genus is invalid as well. A genus is only as good as its type species.

To me, it seems a major problem in our disagreement is that you're giving genera some special significance and tie with their type species (besides the fact a type species has to be within its genus or a senior synonym of that genus; just as a type genus has to be within its family or a senior synonym of that family). But a genus is just another clade, like a family. And a species can be indeterminate within various levels of taxonomy, including genus. Here's my analogy.

Hadrosaurus may be indeterminate within 'family-level' (Prieto-Marquez et al., 2006). The oldest name for a family containing Hadrosaurus is Hadrosauridae. Because it's still definitely a hadrosaurid (in the sense it belongs to this certain 'family-level' clade; not because in ICZN/Phylocode it would have to be a member of its eponymous family), it can remain the type genus for that family. Hadrosaurus is merely an indeterminate genus, alongside diagnosable genera like Edmontosaurus and Parasaurolophus. Of course, foulki is a nomen dubium too, because it is within Hadrosaurus (by definition) and can thus only be placed as accurately as its genus.

suessi may be interminate within 'genus-level' (Sachs and Hornung, 2006). The oldest name for a genus containing suessi is Mochlodon. Because it's still definitely Mochlodon (in the sense it belongs to this certain 'genus-level' clade; not because suessi is the type species of Mochlodon), it can remain the type species for that genus. suessi is merely an indeterminate species, alongside diagnosable species like robustus and shqiperorum. Mochlodon isn't necessarily a nomen dubium though (unlike the previous example), because it isn't within suessi, it's more inclusive than suessi. Just like how Hadrosauridae can be diagnosed even if Hadrosaurus can't.

Now ranks don't really matter here. Families and genera don't need to be objctive entities for the examples to work, they just represent phylogenetic levels where we have potentially competing names.

Another way of looking at it is that suessi is a nomen dubium because it can't be distinguished from at least two valid entities (robustus and shqiperorum). But Mochlodon is synonymous with another taxon, because it can't be distinguished from only one valid entity (Zalmoxes). And because Mochlodon has priority over Zalmoxes, it's a senior synonym.

Mickey Mortimer