Jirahgorgon ceto, new gorgonopsian from Permian of South Africa + monotremes evolutionary history + Kryoryctes + bat wings

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Recent synapsid and mammal papers:

Free pdf:

Jirahgorgon ceto sp. nov.
Phorcyidae fam. nov.

Zanildo Macungo, Ricardo Araújo, Bruce S. Rubidge, Michael O. Day, Kathleen N. Dollman & Julien Benoit (2026)
Evolutionary radiation of large-bodied gorgonopsians from the lower Abrahamskraal formation of South Africa
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.70181
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70181

Free pdf:
https://anatomypubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ar.70181


The middle Permian represents a critical interval in therapsid evolution, when gorgonopsians emerged as some of the first specialized apex predators within terrestrial ecosystems. Despite their significance, the early diversification of Gorgonopsia in Gondwana remains poorly understood due to scarcity and fragmentary material. Here, we describe a nearly complete skull (BP/1/8260) with an occluded lower jaw from the lower Abrahamskraal Formation (Tapinocephalus Assemblage Zone). The specimen exhibits a distinctive combination of cranial features, including a transversely narrow snout, small orbital and temporal openings, V-shaped palatine bosses, and a vertically oriented occiput that distinguish it from all known gorgonopsians. Based on its unique morphology, a new taxon, Jirahgorgon ceto sp. nov., is established for this specimen. In our phylogenetic analysis, the new taxon forms a clade with Phorcys dubei, which is here named Phorcyidae fam. nov. Members of Phorcyidae are unique among basal African gorgonopsians in combining a vertical occiput and rubidgeine-like cranial proportions, indicating that large-bodied gorgonopsians were present in the Wordian and overturning notions that they were exclusively small carnivores until the Wuchiapingian. Basal skull length analyses indicate that body size evolution in Gorgonopsia, while largely random through time (Brownian motion evolutionary model), is nonetheless structured by shared ancestry. The discovery of Jirahgorgon illustrates the complexity of gorgonopsian evolution, showing an early appearance of large-bodied, robust morphotypes and highlighting the lower Abrahamskraal Formation as a key resource for understanding the initial radiation of theriodonts.

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T. Flannery, E. T. Smith, T. Rich, P. Vickers-Rich, M. R. McCurry & K. M. Helgen (2026)
The evolutionary history of the monotremes
Australian Zoologist 45(1): AZ25054.
doi: https://doi.org/10.1071/AZ25054
https://connectsci.au/az/article-abstract/45/1/AZ25054/267844/The-evolutionary-history-of-the-monotremes


Monotremes arose in southern polar environments and were restricted to high latitudes for most of their evolutionary history, explaining their limited global distribution. They may be specialised dryolestids, primitive mammals with a near-global distribution in the Jurassic–Cretaceous. The oldest monotreme fossils are from the Early Cretaceous – 126 million-year-old (Ma) teeth and jaws from southern Victoria, representing a mouse-sized species (Teinolophos trusleri) which had an elongated snout that was used to probe for food. It lived at 76°S, enduring freezing temperatures and 3 months of total darkness each year. The next oldest monotremes, also from southern Victoria, date to 113–108 Ma. They were at least an order of magnitude larger than Teinolophos, around the size of modern Platypus Ornithorhynchus anatinus and echidnas. By the Late Cretaceous (ca. 100 Ma), an age of monotremes had opened in the Australian part of the Gondwanan continent, with six monotreme genera (but no other mammals) co-existing at 60°S at what is now Lightning Ridge, northern NSW. They included an ancestral platypus, another species that was structurally annectant to platypus and echidnas, and a variety of rat to small pig-sized types that appear to have occupied aquatic and terrestrial niches. There are no monotreme fossils yet known from Australia between 100 and 24 Ma, but ancestral platypus, dating to around 70–64 Ma, are known from southern South America. Fossils of toothed platypus (Obdurodon) from central Australia date to around 26 Ma. These are the earliest known non-polar monotremes, living at around 40°S. Rare toothed platypus fossils occur 24–13 Ma, but the oldest known toothless platypus (Ornithorhynchus) date to the Pleistocene (2.5 Ma – 10 ka). After having teeth for 100 million years, Platypus may have lost them because of competition with Water Rats Hydromys chrysogaster. The oldest well-dated echidna fossils are Pleistocene, but genetic studies suggest that the lineage dates back to ca. 50 Ma. Echidnas may have evolved from platypus-like relatives that became isolated on the margin of the paleo-continent Sahul such as on the Vogelkop Island 50–30 Ma. They may have then re-invaded mainland Sahul (i.e. Australia and New Guinea) in the Late Pliocene–Early Pleistocene.

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Free pdf:

Thomas H. Rich & Patricia Vickers-Rich (2026)
Kryoryctes is a monotreme for sure, maybe Open Access
Special Collection: Monotreme Marvels (In Progress)
Australian Zoologist 45(1): AZ25002
doi: https://doi.org/10.1071/AZ25002
https://connectsci.au/az/article/45/1/AZ25002/271628/Kryoryctes-is-a-monotreme-for-sure-maybe


A partial humerus of Kryoryctes cadburyi characterised as ‘tachyglossid-like’ but 100 million years older than the oldest known tachyglossid (echidna) fossil is likely to be a stem monotreme. However, there are a few features of the fossil that are more reminiscent of a therian than a monotreme.

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Free pdf:

S S Zalapa, J M Vargas Aldaco, S Guerrero-Vázquez, F J López Chávez & E R Sánchez (2026)
Unsupervised wing-bone morphogroups in bats reveal phylogenetic and functional patterns
Integrative Organismal Biology, obag007
doi: https://doi.org/10.1093/iob/obag007
https://academic.oup.com/iob/advance-article/doi/10.1093/iob/obag007/8512272


Bat wings are complex biomechanical systems whose skeletal components play a central role in shaping flight performance. Although wing morphology in bats has traditionally been characterized using aerodynamic indices and ecological guilds, the contribution of individual wing bones to emergent patterns of wing design remains poorly understood. Here, we test whether interspecific variation in wing bone proportions is sufficient to generate objective, unsupervised morpho–wing bone groups across Chiroptera. We quantified proportional variation in ten wing bone elements relative to forearm length in 526 individuals representing 59 species from six bat families. Log-ratio–transformed measurements were analyzed using principal component analysis and hierarchical clustering, followed by linear discriminant analysis for group validation. We identified five robust morpho–wing bone groups (MWBGs) that explain coordinated variation in distal, intermediate, and proximal wing elements. These groups were recovered independently of a priori ecological classifications and showed higher discriminant performance than established foraging guilds. Phylogenetic mapping revealed that some MWBGs reflect strong phylogenetic conservatism (e.g., Molossidae), whereas others arise repeatedly across unrelated lineages, suggesting functional convergence in wing skeletal design. Distal phalanges and metacarpals emerged as key contributors to multivariate differentiation. Our results demonstrate that proportional variation in individual wing bones captures fundamental structural dimensions of bat wing morphology and provides a complementary, skeleton-centered framework for investigating the evolution of flight diversity in bats.

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[Mickey Mortimer]

Rich and Vickers-Rich write "A parsimony analysis based on 535 characters of the mammalian skeleton grouped Kryoryctes with the monotremes (Fig. 2). A parsimony analysis based only on the 19 characters available on the holotype of K. cadburyi (see Supplementary material), 31/2% of the total 535 for the entire mammalian skeleton, placed that species within a group of mammals including all the therians, but excluded monotremes (Fig. 2). Thus, the 535-character parsimony analysis seems to be sensitive to the overall morphology of the holotype of K. cadburyi.In contrast, the 19-character parsimony analysis appears to be sensitive to the morphology of the elbow joint."

Since those 19 characters all involve the humerus, um... duh? But more importantly, there's nothing methodologically valuable about reducing an analysis to only those characters scorable in a taxon. The unscorable characters will help organize other taxa whose topology informs the transformation sequence of states in the scorable characters. For instance, in this paper, the Kryoryctes-only analysis places Spinolestes intermediate between Kryoryctes (misspelled Kryorycles in the cladogram and Kryoryxtes in part of the caption- where's peer review?) and therians, but it's sister to Gobiconodon and Repenomamus (misspelled Repannomanus in the cladogram) in the full data analysis. So something therian-like in Spinolestes' humerus is clearly setting up a false set of states for basal Theria. Ditto Castorocauda being a stem-monotreme in the Kryoryctes-only tree as opposed to a docodont like it's (always?) recognized as making a false set of states for that part of the tree too. 

Then their conclusion is "It is highly likely that K. cadburyi is a stem-monotreme. However, the alternative that it just might be more closely allied to therians if not some other tetrapod group, should be kept in mind." Some other tetrapod group? What? And they don't even advocate against the consensus? A certain degree of uncertainty regarding phylogenetic relationships of any fragmentary taxon should just be the default position, but if the authors wanted to test this they should have constrained Kryoryctes as closer to Theria and provided the difference in tree length. But they didn't, so the paper did little to illuminate the relationships of Kryoryctes, and seems most valuable for figuring the premolar MV 208383, assuming that hadn't been done in a prior work.

Mickey Mortimer