Taxacom: On describing new taxa without using phylogenetics: some suggestions

[Marko Mutanen]

Dear Kirk,

Thanks for your comment.

I agree that this is true at a philosophical level, but it does not necessarily hold true at a practical level. It is quite possible that morphology, or certain other types of data, are so noisy that they mislead more than they inform. In my experience, morphological and DNA data often produce highly contradictory phylogenies. A consensus between the two is not necessarily more reliable than one based solely on large amounts of DNA data.

I recognize the philosophical weaknesses of this reasoning, but as Robert noted, DNA provides far more information and tends to be less biased. It should also be remembered that all taxonomically relevant morphological information is ultimately encoded in DNA, so combining both raises additional philosophical challenges. Homoplasy in morphology often results from natural selection, but this convergence rarely translates into DNA. Although DNA also contains homoplasy, it tends to be random, whereas morphological homoplasy is often systematic and directional.

Sincerely,

Marko M.

From: Kirk Fitzhugh <kfitzhugh at nhm.org>
Sent: keskiviikko 8. lokakuuta 2025 22.18
To: Marko Mutanen <Marko.Mutanen at oulu.fi>
Cc: Lücking, Robert <R.Luecking at bo.berlin>; John Grehan <calabar.john at gmail.com>; Kuoi Zhang <zhang.guo-yi at outlook.com>; taxacom at lists.ku.edu
Subject: Re: Taxacom: On describing new taxa without using phylogenetics: some suggestions

Marko Mutanen,

Given that our intent with phylogenetic inferences is to causally account for observed homologous characters, and this occurs via the non-deductive form of reasoning known as abduction, there are no logical arguments supporting the view that sequence data has some priority over other classes of characters. Homoplasy is an ad hoc hypothesis that is the product of inferring hypotheses, so it can't be used as an excuse to exclude morphological characters (indeed, one can just as easily argue that sequence data are just as prone to lead to hypotheses of homoplasy). The only rational approach to abductively inferring phylogenetic hypotheses is to abide by the requirement of total evidence (sensu Carnap 1950) and consider all relevant observed characters.

Kirk Fitzhugh

On Wed, Oct 8, 2025 at 12:02 PM Marko Mutanen via Taxacom <taxacom at lists.ku.edu<mailto:taxacom at lists.ku.edu>> wrote:
Dear Robert, all, I agree with you. Morphological evolution is indeed fascinating, but it should be studied in the context of DNA-based phylogenies rather than by continuing to infer evolutionary relationships solely from morphology, which is

Dear Robert, all,



I agree with you. Morphological evolution is indeed fascinating, but it should be studied in the context of DNA-based phylogenies rather than by continuing to infer evolutionary relationships solely from morphology, which is highly prone to homoplasy. Of course, when dealing with fossils, we must still rely on morphological data, but this inevitably introduces substantial uncertainty into the taxonomy of extinct taxa - likely persisting indefinitely.



Sincerely,



Marko M.