Mixodectes enters the LRT with Apatemys and Labidolemur, not pre-primates
From the Chester et al 2025 abstract:
“Mixodectids are poorly understood placental mammals from the Paleocene of western North America that have variably been considered close relatives of euarchontan mammals (primates, dermopterans, and scandentians) with hypothesized relationships to colugos, extinct plagiomenids, and/or microsyopid plesiadapiforms.”
Missing from this list are apatemyids like Labidolemur and Apatemys (Figs 1–4). In the large reptile tree (LRT, 2336 taxa) Mixodectes nests with Apatemys and Labidolemur.
Figure 1. Mixodecte from Chester et al. Manual and pedal elements are combined and compared to Apatemys here.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg?w=192″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg?w=584″ class=”size-full wp-image-91960″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg” alt=”Figure 1. Mixodecte from Chester et al. Manual and pedal elements are combined and compared to Apatemys here. ” width=”584″ height=”913″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg?w=584&h=913 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg?w=96&h=150 96w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg?w=192&h=300 192w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skeleton.ventral588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 1. Mixodecte from Chester et al. Manual and pedal elements are combined and compared to Apatemys here.
From the Chester et al 2025 abstract:
“Here we describe the most complete dentally associated skeleton yet recovered for a mixodectid, specifically Mixodectes pungens from the early Paleocene of the San Juan Basin, New Mexico. A partial skull with all the teeth erupted and associated axial skeleton, forelimbs, and hind limbs, with epiphyses fused, indicate that it was a mature adult. Results from cladistic analyses incorporating new data robustly support primatomorphan (Primates + Dermoptera) affinities of Mixodectidae, but relationships within Euarchonta are less clear, with Mixodectes recovered as a stem primatomorphan, stem dermopteran, or stem primate.”
The LRT tests all those possibilities. Taxon exclusion marred this study.
In the LRT dermopterans are primates. So are bats. Apatemyids are different, closer to Labidolemur, which was studied by co-authors Bloch and Silcox.
Apatemys and Labidolemur studies are listed in the Chester et al citation list.
Figure 2. Mixodectes skull reconstructed here for the first time based on photos in Chester et al. DGS colors applied here. Apatemys and Sinclairella are shown for comparison and to hypothetically fill in missing parts.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg?w=584″ class=”size-full wp-image-91962″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg” alt=”Figure 2. Mixodectes skull reconstructed here for the first time based on photos in Chester et al. DGS colors applied here. Apatemys and Sinclairella are shown for comparison and to hypothetically fill in missing parts. ” width=”584″ height=”582″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg?w=584&h=582 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg?w=150&h=150 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg?w=300&h=300 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.skull588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 2. Mixodectes skull reconstructed here for the first time based on photos in Chester et al. DGS colors applied here. Apatemys and Sinclairella are shown for comparison and to hypothetically fill in missing parts. Note the otherwise rare dual parasagittal crests on the parietal.
The manus and pes of Mixodectes
are incompletely known. Chester et al attempted to reconstruct them. Here (Figs 3, 4) digit 1 is switched with 5 on both the manus and pes. This resulting pattern closely matches that of Apatemys.
Figure 3. The manus of Mixodectes compared to that of Apatemys. Compare to Chester et al in figure 1.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg?w=584″ class=”size-full wp-image-91964″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg” alt=”Figure 3. The manus of Mixodectes compared to that of Apatemys. Compare to Chester et al in figure 1. ” width=”584″ height=”545″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg?w=584&h=545 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg?w=150&h=140 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg?w=300&h=280 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.manus588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 3. The manus of Mixodectes compared to that of Apatemys. Compare to Chester et al in figure 1.
Mixodectes has relatively shorter hind legs
and shorter metatarsals than the smaller, more derived taxon, Apatemys.
Figure 4. The pes of Mixodectes compared to that of Apatemys. Compare to reconstructions offered by Chester et al in figure 1.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg?w=266″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg?w=584″ class=”size-full wp-image-91966″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg” alt=”Figure 4. The pes of Mixodectes compared to that of Apatemys. Compare to reconstructions offered by Chester et al in figure 1.” width=”584″ height=”659″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg?w=584&h=659 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg?w=133&h=150 133w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg?w=266&h=300 266w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/03/mixodectes.apatemys.pes588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 4. The pes of Mixodectes compared to that of Apatemys. Compare to reconstructions offered by Chester et al in figure 1. Mixodectes is more primitive in the LRT.
Chester et al wrote,
“Plesiadapiforms are recovered as either stem primatomorphans (Purgatorius, Foxomomys fremdi, Tinimomys graybulliensis, Dryomomys szalayi, Plesiolestes nacimienti), stem dermopterans(Microsyops annectens), or as stem primates (Ignacius, Carpolestes simpsoni, Plesiadapis).
By contrast, in the LRT plesiadapiformes, Carpolestes and kin (including Daubentonia, the aye-aye) are all members of Glires and not close to primates, which lack the oversize incisors seen in Mixodectes, apatemyids, multitureberculates, rodents and kin. They are one of several origins for the placenta not related to the primate + carnivore + artiodactyl placenta.
It’s an old myth/tradition that pleasiadapiformes are related to primates.
The authors, editors and referees all supported this tradition.That’s how papers like this get published. However, after testing the LRT does not that tradition.
Add taxa to your own cladogram to find this out for yourself.
The authors also employed certain genomic suprageneric taxa
(e.g. Afrotheria). This also did them a disservice.
There are too many false traditions in paleontology.
These create vacuums of understanding. The LRT removes those vacuums and clarifies all phylogenetic issues simply by adding taxa and therefore minmizing taxon exclusion.
It’s that easy. But it does take time. (gentle prod to academics)
Googling ‘Mixodectes’
pulls up several web clade pages – including Glires. Until the skeleton and skull described in Chester et al, too few clues were available to make a determination. Now there are enough clues, so long as pertinent taxa are not excluded from consideration.
Given the fact that co-authors Silcox and Bloch
had both studied Labidolemur and apatemyids, I think they would have succeeded had they just added apatemyids to their cladogram.
Ironic.
References
Chester SGB et al (5 co-authors) 2025. New remarkably complete skeleton of Mixodectes reveals arboreality in a large Paleocene primatomorphan mammal following the Cretceous-Paleodene mass extinction. Nature Scientific Reports15:8041
https://doi.org/10.1038/s41598-025-90203-z
Source: https://pterosaurheresies.wordpress.com/2025/03/14/mixodectes-enters-the-lrt-with-apatemys-and-labidolemur-not-pre-primates/
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world. Anyone can join. Anyone can contribute. Anyone can become informed about their world. "United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
LION'S MANE PRODUCT
Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules
Mushrooms are having a moment. One fabulous fungus in particular, lion’s mane, may help improve memory, depression and anxiety symptoms. They are also an excellent source of nutrients that show promise as a therapy for dementia, and other neurodegenerative diseases. If you’re living with anxiety or depression, you may be curious about all the therapy options out there — including the natural ones.Our Lion’s Mane WHOLE MIND Nootropic Blend has been formulated to utilize the potency of Lion’s mane but also include the benefits of four other Highly Beneficial Mushrooms. Synergistically, they work together to Build your health through improving cognitive function and immunity regardless of your age. Our Nootropic not only improves your Cognitive Function and Activates your Immune System, but it benefits growth of Essential Gut Flora, further enhancing your Vitality.
Our Formula includes: Lion’s Mane Mushrooms which Increase Brain Power through nerve growth, lessen anxiety, reduce depression, and improve concentration. Its an excellent adaptogen, promotes sleep and improves immunity. Shiitake Mushrooms which Fight cancer cells and infectious disease, boost the immune system, promotes brain function, and serves as a source of B vitamins. Maitake Mushrooms which regulate blood sugar levels of diabetics, reduce hypertension and boosts the immune system. Reishi Mushrooms which Fight inflammation, liver disease, fatigue, tumor growth and cancer. They Improve skin disorders and soothes digestive problems, stomach ulcers and leaky gut syndrome. Chaga Mushrooms which have anti-aging effects, boost immune function, improve stamina and athletic performance, even act as a natural aphrodisiac, fighting diabetes and improving liver function. Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules Today. Be 100% Satisfied or Receive a Full Money Back Guarantee. Order Yours Today by Following This Link.
| Online: | |
| Visits: | 1,682,030,744 |
| Stories: | 8,371,110 |
Whistler Blowers, Insiders
