Changes to the basal vertebrate subset of the LRT

Over the past several weeks
and especially the last several days, several dozen included taxa in the LRT have been reexamined and re-scored based on comparisons to other included taxa. Apparently the teleost (bony fish) section of the large reptile tree (LRT, 1655+ taxa; Fig. 1) has reached some sort of critical mass of taxa in which each taxon now has one to several ‘similar-enough’ taxa to enable side-by-side comparisons to identify inconsistent interpretations, overlooked bones and miscellaneous errata. Some of the data comes in the form of fifty-year-old drawings. Others from published x-rays. Still others from carefully prepared skulls. Yet others are studied from small, low resolution images. Overlooked vestigial and hidden structures have been identified. Sutures have been redrawn. Reconstructions have shed light on bone splinters and shards.

Corrections revealed earlier errors. 
As I’ve said on several occasions, I knew nothing about fish morphology before this study, gaining knowledge with every taxon. To students of science, this is the process, perhaps delivered more transparently than traditional works. Thankfully, none of this was printed. Instead, online presentations like this permit corrections and invite comments during the process… not just after publication.

Some highlights in the list of changes to the LRT (Fig. 1) include:

  1. Three eels now nest with Amia, the bowfin, a basal teleost, despite the loss of several cheek bones that typically mark derived taxa.
  2. Two more eels now nest with Gregorius, the proximal outgroup taxon to the basal dichotomy that splits the bony fish.
  3. The odd whitefish, Albula, now nests with the tarpon, Megalops.
  4. The frogfish, Antennarius, now nests with the mudskipper, Periophthalmus, rather than the goosefish, Lophius. 

Over the next few days
these novel hypotheses and others will be presented so you can share in the process of discovery.

The LRT is a powerful tool
that highlighted earlier errors in a feedback loop. Having a fully resolved cladogram is no guarantee that the resulting tree topology is correct at every node. High Bootstrap scores remain the goal. Reexamination is part of the process.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.