Molecular trees can provide essential information for the phylogeny of groups but what about systematic/taxonomy at species/subspecies level? Is here morphology still leading the game?
In Clausiliidae systematics, molecular methods often reveal conflicting results with that of morphology. At species level molecular cues are helpful to idenfify hybridization and cryptic speciation. As current methods in forming 'systems' are rather based on chracters like dentition and lamellae validity of which is refused by molecular methods in general, delinenations of species and even more so subspecies may not be compatible.
the reason is that molecvular methods normally employ immunochemical methods that normally (90%) are useless as no VALIDATED antibodies are used in the majority of cases generating junk in protein science
Dear Unit, thanks so much for your answer.
What do you mean by "characters like dentition and lamellae validity of which is refused by molecular methods"?
Do you mean that molecular and morphological (NB: shell only until now in clausiliids) are somehow divergent and conflicting? My question is: is there any kind of "genetic distance" that delineates and discriminate among specific and subspecific ranking?
The answer is "YES" because by the definition of genetic distance is a measure of the genetic divergence between species or between populations within a species.
Thanks Otaringho! Could you provide some additional hint about it? What (numeric!) range of genetic distance should be considered to delineate a specific difference? And concerning subspecies? Should all the groups follow the same ranges or every group has a different range value due to intrinsic genetic reasons? I.e.: does troglofauna show different genetic patterns comparing to surface fauna, thus showing different limit ranges? And what's is the role of morphology among all these factors? ..sometimes it seems like the morphology will be totally discarded in favor of molecular taxonomy...
Not always (at least nowadays). At least at the species level in plants systematics, depending on the genera and species, you will have sometimes polytomies at the species level. Even more, you have sometimes terminal clades with only two species. You need the morphology to distinguish both species or to confirm if they are the same. I have the experience of some genera with a recent radiation, in which the sequences of 7 different markers (nuclear and plastid) show almost no variation between the species and then, you have a polytomy. However, in that genus the species are very different and easy to distinguish based on morphology.
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