this post was submitted on 12 May 2024
229 points (99.1% liked)
Asklemmy
43831 readers
1178 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy ๐
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- !lemmy411@lemmy.ca: a community for finding communities
~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
The diapsid part is very likely indeed, as fossil skulls of early stem turtles do show some temporal openings ( https://www.annualreviews.org/content/journals/10.1146/annurev-ecolsys-110218-024746 ) The point is more where do they nest within Diapsida, more closely to the Lepidosauromorpha, or to the Archosauromorpha, and where precisely if within one of those clades. The point is that can't quite be proven using only extant species, whether by DNA or morphological evidence. And concerning ML, the methodology is often criticised, not because it's bad, but because it's opaque and thus it is difficult to justify and understand as a process
Three robust genetics papers using different sequences and genes, each time place it as a sister group to Archosauria:
248 nuclear genes (187,026 nucleotide sites): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3473239/
1145 ultraconserved elements (UCEs) and their variable flanking DNA: https://royalsocietypublishing.org/doi/10.1098/rsbl.2012.0331
1,113 single-copy coding genes, robustly indicated that turtles are likely to be a sister group of crocodilians and birds: https://www.nature.com/articles/ng.2615
This level of genetic evidence is an overwhelmingly strong signal, regarding relationships and recent common ancestry to extant species. I would say it is undeniably strong. You cannot possibly get evolutionary convergence over this many genetic loci.