[Paleontology • 2026] The ontogenetically youngest known pachycephalosaur (Dinosauria: Ornithischia) postcranium

 

juvenile Pachycephalosauria indet. (CMNFV 22039)
Life reconstruction in an environment typical of the upper Maastrichtian Frenchman Formation, Saskatchewan. 

in Moore, Evans, Ryan, Patterson et Mallon, 2026. 

  DOI: doi.org/10.1080/02724634.2026.2616325

Illustration by Kaitlin Lindblad. 

 x.com/Jordan_Mallon

 

ABSTRACT

Pachycephalosaurian dinosaurs are represented in the fossil record primarily by their taphonomically resistant frontoparietal domes that developed fully only at maturity. Consequently, the postcranial record of Pachycephalosauria is poor, particularly for immature forms. Here, we describe the ontogenetically youngest known, and Canada’s second-most complete, pachycephalosaur postcranium, collected from the uppermost Maastrichtian Frenchman Formation, Saskatchewan. Despite its small size (estimated total length ∼90 cm), the skeleton shows several characters diagnostic of Pachycephalosauria, including a double ridge-and-groove articulation on the pre- and postzygapophyses of the dorsal neural arches, a medial flange on the postacetabular process of the ilium, and a highly reduced pubis that contributes only minimally to the acetabular margin. Histological sectioning of the crural bones shows an immature woven bone texture. The absence of cyclical or annual growth indicators suggests that this specimen was less than a year old at the time of death. Phylogenetic analysis recovers the specimen as a member of Pachycephalosaurinae, perhaps related to Prenocephale, but the lack of cranial data for our specimen and the complementary lack of postcranial data for other pachycephalosaurs make this determination tenuous. Spatiotemporal considerations suggest a possible but currently untestable affiliation with Sphaerotholus buchholtzae. The relatively long hindlimbs of the juvenile compared with those of adult pachycephalosaurs indicate probable negative ontogenetic allometry in the hindlimbs.

 Preserved elements (in red) of juvenile Pachycephalosauria indet. (CMNFV 22039).
 The preserved left ischium does not show in this view. Diagram illustrates preserved elements only and does not accurately reflect the proportions of CMNFV 22039.

Skeletal drawing modified after original illustrations of Pachycephalosaurus (postcranium) and “Dracorex” (cranium) by Gregory Paul. Used with permission.

Life reconstruction of CMNFV 22039 in an environment typical of the upper Maastrichtian Frenchman Formation. 

Illustration by Kaitlin Lindblad. Used with permission.

 

Bryan R. S. Moore, David C. Evans, Michael J. Ryan, R. Timothy Patterson and Jordan C. Mallon. 2026. The ontogenetically youngest known pachycephalosaur (Dinosauria: Ornithischia) postcranium. Journal of Vertebrate Paleontology. e2616325. DOI: 10.1080/02724634.2026.2616325 [26 Feb 2026]

 www.tandfonline.com/doi/full/10.1080/02724634.2026.2616325

 x.com/Jordan_Mallon/status/2027031604879835644

[Paleontology • 2025] Recovering lost time in Syria: A gigantic latest Cretaceous azhdarchid Pterosaur from the Palmyrides Mountain Chain

 

Syrian azhdarchid (LU-GD 0001)

in Alhalabi, Pinheiro, Jaoude, Ismail, Suberbiola, Bardet et Langer, 2025.

 DOI: doi.org/10.1007/s00114-025-02032-9  

  x.com/WhWafa

Abstract

Azhdarchidae was a diverse group of toothless pterosaurs and one of the few lineages of flying reptiles to survive to the end of the Cretaceous. Despite including medium-sized forms, the group is notable for their gigantic representatives, which correspond to the largest known flying animals. Azhdarchids had a nearly global distribution during the Late Cretaceous, including the Arabian Plate, with records in Lebanon and Jordan, such as the iconic Arambourgiana philadelphiae. Here, we report the first azhdarchid, and indeed the first pterosaur, from Syria, recovered from early Maastrichtian phosphate deposits of the Palmyrides mountain chain, near Palmyra (Tadmur). It corresponds to a fragmentary left humerus, missing both its proximal and distal ends, with a preserved length of 289 mm. The Syrian pterosaur was exceptionally large, with extrapolations suggesting that, if complete, its humerus would be only about 10% smaller than the holotype humerus of Quetzalcoatlus northropi, the largest known pterosaur. The new pterosaur fossil also represents the uncommon record of a giant azhdarchid in marine deposits, confirming that these gigantic animals, though classically considered continental, could also inhabit nearshore environments. The find also underscores the widespread occurrence of gigantic azhdarchids until the latest Cretaceous, just prior to their Cretaceous/Paleogene extinction, and highlights the potential for fossil discoveries in understudied regions such as the Middle East.

 

Keywords: Azhdarchidae, Pterosaurs, Azhdarchids

Syrian azhdarchid (LU-GD 0001)

Conclusions: 

Despite the incompleteness of the Syrian azhdarchid (LU-GD 0001), it is significant given its size and geographic provenance. Firstly, it corresponds to one of the largest known pterosaurs and the first pterosaur found in Syria, adding to previously documented Middle East records from Jordan and Lebanon. It is also an additional record of an azhdarchid from marine strata, adding to the evidence that these gigantic animals were not strictly continental, but also able to live near the coastlines. The Syrian azhdarchid also reinforces the widespread distribution of those gigantic pterosaurs just prior to their extinction at the end of the Cretaceous. Finally, it is a witness that the Palmyrides phosphate mines of Syria are continuously yielding important fossil specimens, so that their exploration is likely to uncover further new finds, expanding our understanding of the Middle East ancient life.

 

Wafa A. Alhalabi, Felipe L. Pinheiro, Issam Bou Jaoude, Mohamad J. Ismail, Xabier Pereda Suberbiola, Nathalie Bardet and Max C. Langer. 2025. Recovering lost time in Syria: A gigantic latest Cretaceous azhdarchid Pterosaur from the Palmyrides Mountain Chain. The Science of Nature.  112 78. DOI: doi.org/10.1007/s00114-025-02032-9 [16 October 2025]

 x.com/WhWafa/status/1978824576772550697

[Paleontology • 2025] Direct Evidence of Trophic Interaction between a crocodyliform and a large terror bird in the Middle Miocene of La Venta, Colombia

 a caimanine alligatorid (Purussaurus neivensis) preying/scavenging on a large phorusrhacid bird.
 

in Link, Moreno-Bernal, Degrange, Cooke, ... et Salas-Gismondi, 2025.

DOI: doi.org/10.1098/rsbl.2025.0113

Illustrations by Julian Bayona Becerra. 

Abstract

Direct evidence of predation and other trophic relationships provide valuable information about trophic interactions between species in palaeo-communities. Data on ecological interactions amongst extant apex predators open a unique opportunity to better understand how sympatric apex predators coexisted or interacted with each other in the past. Here, we describe direct evidence of a predation or scavenging event in which we hypothesize that a medium-sized caiman (possibly Purussaurus neivensis) consumed (either through scavenging or through direct predation) a large terror bird. The distal part of a left tibiotarsus from a phorusrhacid had four pits inflicted on the cortical bone, and no signs of healing, suggesting it did not survive this trophic event. This record contributes to our current understanding of prey consumed by P. neivensis in the wetlands of the Pebas System of South America and indicates that large phorusrhacids might have had higher predation risk than previously expected. This study provides evidence of a trophic relation between apex predators and the complexity of trophic interactions in the diverse vertebrate palaeo-community of La Venta in the Middle Miocene of northern South America.

Keywords: apex predators, Phorusrhacidae, Purussaurus, superpredation, taphonomy, Caimaninae, scavenging

 

(a) Superimposed 3D models of MT−0200 and a skull of extant black caiman (Melanosuchus niger UF-Herp-53600). Both models at the same scale, the M. niger model is archived on Morphosource (https://doi.org/10.17602/M2/M359353). Total length estimated for the specimen of M. niger is 4.84 meters and is used here as an analogy to a medium sized Purussaurus (skull or mandible not available) [49]. Scale bar is 50 mm. (b) Detail of the superimposed model, showing the close match between the teeth of UF-Herp-53600 and the tooth marks on MT-0200. Scale bar is 50 mm.
(c) Artistic representation of a caimanine alligatorid (Purussaurus neivensis) preying on a large phorusrhacid bird. (d) Artistic representation of a caimanine alligatorid (Purussaurus neivensis) scavenging on a large phorusrhacid bird. Illustrations by Julian Bayona Becerra.  

 

Andres Link, Jorge Wilson Moreno-Bernal, Federico Javier Degrange, Siobhan B. Cooke, Luis Gonzalo Ortiz-Pabon, Cesar Augusto Perdomo-Rojas and Rodolfo Salas-Gismondi. 2025. Direct Evidence of Trophic Interaction between a crocodyliform and a large terror bird in the Middle Miocene of La Venta, Colombia. Biol. Lett. 21; 20250113. DOI: doi.org/10.1098/rsbl.2025.0113 [23 July 2025]

[PaleoEntomology • 2021] Jurassic Scorpionflies (Mecoptera) with swollen first metatarsal segments suggesting Sexual Dimorphism

  

Comparison of non-swollen versus swollen first metatarsal segments. 
 a, b Non-swollen, Mesopanorpa densa. c, d Heavily swollen, Mesopanorpa luanpingensis. e, f Slightly swollen, Orthophlebia elenae. g, h Moderately swollen, Mesopanorpa densa. 
i Artist’s reconstruction of orthophlebiids with the first metatarsal segment slightly swollen (male at left) or extremely swollen (male at center).

in Zhang, P.J.M. Shih, Wang, McNamara, C. Shih, Ren et Gao, 2021.

DOI: doi.org/10.1186/s12862-021-01771-3

 (artwork by Dr. Chen Wang)

Abstract

Background: Sexual dimorphism is widespread in insects. The certain specialized structures may be used as weapons in male–male combats or as ornaments to enhance mating opportunities.

Results: We report striking swollen first tarsal segments in two families, four genera and six species of scorpionflies from the Middle Jurassic Yanliao Biota of Northeastern China. Swollen tarsal segments are restricted to male specimens and to hind leg tarsi. The geometric morphometric analyses reveal that the degree of swelling within the orthophlebiid species possessing swollen first metatarsal segments is species-specific, which can be used as a diagnostic character for taxonomic and phylogenetic studies.

Conclusions: The new findings indicate that swollen first metatarsal segments are relatively common in the family Orthophlebiidae during the Middle Jurassic. The tarsal swellings are considered to be sexually dimorphic, potentially associated with sexually display by males and/or camouflage of a “nuptial gift” in the mating process.

Keywords: Fossil insect, Holcorpidae, Mesozoic, Orthophlebiidae, Tarsal swelling, Nuptial gift, Yanliao Biota

Comparison of non-swollen versus swollen first metatarsal segments.
 a, b Non-swollen, Mesopanorpa densa (CNU-MEC-NN2016270). c, d Heavily swollen, Mesopanorpa luanpingensis (CNU-MEC-NN2016229). e, f Slightly swollen, Orthophlebia elenae (CNU-MEC-NN2014020). g, h Moderately swollen, Mesopanorpa densa (CNU-MEC-NN2016253).
i Artist’s reconstruction of orthophlebiids with the first metatarsal segment slightly swollen (male at left) or extremely swollen (male at center) (credit: Dr. Chen Wang).

b, d, f, h Habitus, first metatarsal segments of (a, c, e, g). Scale bars represent: 4 mm for (a, c, e, g); 0.5 mm for (b, d, f, h)

Yan-jie Zhang, Peter J. M. Shih, Jun-you Wang, Maria E. McNamara, Chungkun Shih, Dong Ren and Tai-ping Gao. 2021. Jurassic Scorpionflies (Mecoptera) with swollen first metatarsal segments suggesting Sexual Dimorphism. BMC Ecology and Evolution. 21: 47. DOI: doi.org/10.1186/s12862-021-01771-3 [20 March 2021]

[Paleontology • 2025] First Occurrence of the Duck-billed Dinosaur Tribe Lambeosaurini (Hadrosauridae: Lambeosaurinae) in South China

Lambeosaurini from Dalangshan Formation of Sihui City, China

in Wang, Xing, Mallon, Miyashita, Za. Liang, Zhang, Ren, Zh. Liang et Xian, 2025.

DOI: doi.org/10.1080/08912963.2025.2454652 

ABSTRACT

Late Cretaceous Laurasia contained a typical dinosaur fauna consisting of herbivorous hadrosaurids, ceratopsians, and carnivorous tyrannosauroids. Previously, tyrannosauroid teeth have been found in the Upper Cretaceous Dalangshan Formation of Sihui City, China. We describe a fragmentary skeleton of a duck-billed dinosaur from the same general region. The skeleton includes dorsal and caudal vertebrae, a humerus, ilium, femur and tibia. Morphological comparison and cladistic analyses support that this specimen belongs to the tribe Lambeosaurini, which is otherwise poorly represented in China. The new specimens and the previously discovered tyrannosauroid teeth represent the dominant taxa of the typical Late Cretaceous dinosaur fauna of Laurasia.

KEYWORDS: Dinosauria, Hadrosauridae, Lambeosaurinae, Lambeosaurini, Maastrichtian

 the Sihui Museum specimen

Restoration drawing by Han Zhixin

Donghao Wang, Lida Xing, Jordan C. Mallon, Tetsuto Miyashita, Zaoqun Liang, Xianqiu Zhang, Zheng Ren, Zhicong Liang and Minyi Xian. 2025. First Occurrence of the Duck-billed Dinosaur tribe Lambeosaurini (Hadrosauridae: Lambeosaurinae) in South China. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2025.2454652 

[Paleontology • 2024] Early–middle Permian Mediterranean gorgonopsian suggests an equatorial origin of therapsids

a gorgonopsian from the island of Mallorca, western Mediterranean

in Matamales-Andreu, Kammerer, Angielczyk, Simões, Mujal, Galobart et Fortuny, 2024.  

DOI: doi.org/10.1038/s41467-024-54425-5  

Reconstruction by Henry Sutherland Sharpe

Abstract

Therapsids were a dominant component of middle–late Permian terrestrial ecosystems worldwide, eventually giving rise to mammals during the early Mesozoic. However, little is currently known about the time and place of origin of Therapsida. Here we describe a definitive therapsid from the lower–?middle Permian palaeotropics, a partial skeleton of a gorgonopsian from the island of Mallorca, western Mediterranean. This specimen represents, to our knowledge, the oldest gorgonopsian record worldwide, and possibly the oldest known therapsid. Using emerging relaxed clock models, we provide a quantitative timeline for the origin and early diversification of therapsids, indicating a long ghost lineage leading to the evolutionary radiation of all major therapsid clades within less than 10 Myr, in the aftermath of Olson’s Extinction. Our findings place this unambiguous early therapsid in an ancient summer wet biome of equatorial Pangaea, thus suggesting that the group originated in tropical rather than temperate regions.

Systematic palaeontology

Synapsida Osborn, 190313

Therapsida Broom, 190514

Gorgonopsia Seeley, 189415

Gorgonopsia indet.

Most relevant elements of DA21/17-01-01 and silhouette showing their positions

 Life reconstruction of the gorgonopsian from Mallorca in a floodplain setting.

Reconstruction by Henry Sutherland Sharpe

 Rafel Matamales-Andreu, Christian F. Kammerer, Kenneth D. Angielczyk, Tiago R. Simões, Eudald Mujal, Àngel Galobart and Josep Fortuny. 2024. Early–middle Permian Mediterranean gorgonopsian suggests an equatorial origin of therapsids. Nature Communications. 15: 10346. DOI: doi.org/10.1038/s41467-024-54425-5  

[PaleoOrnithology • 2024] A gigantic new Terror Bird (Cariamiformes: Phorusrhacidae) from Middle Miocene tropical environments of La Venta in northern South America

  

'Phorusrhacinae' Gen. et sp. indet. [MT-0200]

in Degrange, Cooke, Ortiz-Pabon, Pelegrin, Perdomo, Salas-Gismondi & Link, 2024.

DOI: 10.1002/spp2.1601 

 x.com/ThePalAss 

  facebook.com/PaleobiologiaUN

Abstract

Our knowledge of the fossil avifauna from the Middle Miocene La Venta locality in Colombia is limited almost entirely to aquatic birds. Phorusrhacidae, popularly known as ‘terror birds’, are a group of highly diversified cursorial birds that played the role of apex predators during most of the Cenozoic. Here we present the first record of a phorusrhacid from the La Venta locality. This terror bird can be assigned to the ‘Phorusrhacinae’, a subfamily for which the monophyly is under debate. The fragment of left distal tibiotarsus represents the most northern record of this group for South America and may correspond to the largest terror bird that ever existed. This suggests that terror birds might also have inhabited more tropical ecosystems, providing evidence that they were apex predators in tropical palaeocommunities. Additionally, our research contributes to an understanding of the biogeographical patterns of the Phorusrhacidae lineage dispersal into northern South America and subsequent colonization of North America.

Keywords: terror bird, La Venta, predator, palaeoecosystem, Miocene, phorusrhacid

Class: Aves 

Order: Cariamiformes 

Family: Phorusrhacidae 

Subfamily: 'Phorusrhacinae'

 Gen. et sp. indet.

MT-0200

Federico J. Degrange, Siobhan B. Cooke, Luis G. Ortiz-Pabon, Jonathan S. Pelegrin, Cesar A. Perdomo, Rodolfo Salas-Gismondi and Andrés Link. 2024. A gigantic new Terror Bird (Cariamiformes, Phorusrhacidae) from Middle Miocene tropical environments of La Venta in northern South America. Papers in Palaeontology. DOI: doi.org/10.1002/spp2.1601 

  x.com/ThePalAss/status/1853430761765957982

  facebook.com/PaleobiologiaUN/posts/1181483590175198

  facebook.com/PaleontologiaenColombia/posts/1078533020940011

[PaleoBotany • 2023] First Recognition of the Extinct Eudicot Genus Palibinia in North America: Leaves and Fruits of Palibinia comptonifolia (R.W.Br.) comb. nov. from the Eocene of Utah and Colorado, USA

Palibinia comptonifolia (R.W.Br.) comb. nov. 

in Manchester, Judd et Kodrul, 2023. 

DOI: doi.org/10.1111/jse.13011

 

Abstract

Newly investigated leafy twigs bearing axillary fruits from the Eocene Parachute Creek Member of the Green River Formation in eastern Utah, USA, have provided more information on the species previously attributed to the Proteaceae as Banksia comptonifolia R.W.Br. The leaves are simple, estipulate with short petioles, and elongate laminae with prominent angular nonglandular teeth. The laminae have a thick midvein and pinnate craspedodromous secondaries, and are distinctive in the presence of a thick, often coalified, marginal rim. Vegetative and reproductive buds occur in the axils of the leaves. These features indicate that the species belongs to Palibinia Korovin—an extinct Eudicot genus previously known only from the Paleogene of Asia and Europe. Small pedicellate ovoid fruits 1.5–2.2 mm wide are borne in fascicles of three and are seen to be capsules with four apical valves. Despite the specific epithet referring to similarity of the foliage to that of Comptonia (Myricaceae), the fasciculate inflorescence organization with axillary flowers is quite distinct from the catkins characteristic of that family. Assignment to Banksia or other Proteaceae with complex inflorescences and follicular fruits is also problematic. Additionally, MacGinitie′s transfer of the species to Vauquelinia of the Rosaceae is contradicted by the lack of stipule scars on the twig and by differences in leaf venation and floral morphology. We transfer the species to Palibinia comptonifolia (R.W.Br.) comb. nov., but its familial affinity within the Pentapetalae remains uncertain. This new occurrence augments records from the Paleogene of Turkmenistan, Kazakhstan, China, England, and Germany.

Palibinia comptonifolia (R.W.Br.) comb. nov. leafy twigs in a slab of shale from Bonanza, UT. DMNH EPI.43698.
A, Portions of three twigs showing alternate leaves. B, Enlargement of a twig with mature leaves giving rise to a flush of new growth. C, Another portion of a twig enlarged from (A), showing the axillary position of young fruits. D, Enlargement from (C), with pedicellate axillary globose fruits. E, Enlargement from another twig in (A), showing an axillary fruit.

F–H, Individual twigs digitally extricated from the image of (A). 

Scale bars = 2 cm in (A), (F–H), 1 cm in (B, C), 5 mm in (D, E).

Systematics

Group Pentapetalae D.E. Soltis, P.S. Soltis & W.S. Judd

Order indet.

Family indet.

Genus Palibinia Korovin

Palibinia comptonifolia (R.W.Br.) comb. nov.

Conceptual diagrams of Palibinia twigs.
A, B, Palibinia comptonifolia (R.W.Br.) comb. nov. twigs including axillary fruits and vegetative growth, diagram by Ashley Hamersma.
C–E, Original diagrams of Korovin (1932), slightly enhanced and reduced. C, Twig of Palibinia laxifolia Forma laxifolia showing axillary flowers or fruits. D, Forma densifolia. E, Forma lanceolata.

 

Steven R. Manchester, Walter S. Judd and Tatiana Kodrul. 2023. First Recognition of the Extinct Eudicot Genus Palibinia in North America: Leaves and Fruits of Palibinia comptonifolia (R.W.Br.) comb. nov. from the Eocene of Utah and Colorado, USA. Journal of Systematics and Evolution. DOI: doi.org/10.1111/jse.13011

  x.com/AsiaPaleoFloras/status/1696603495183405158

[Paleontology • 2024] The First Occurrence of a Basal Tyrannosauroid in Southeast Asia: Dental Evidence from the Upper Jurassic of Northeastern Thailand

Tyrannosauroidea indet.

in Chowchuvech, Manitkoon, Chanthasit et Ketwetsuriya, 2024.

   li01.tci-thaijo.org/index.php/TNH/article/view/261261

  facebook.com/ESciKU

Illustration: Chatcharin Somboon.

Abstract

Isolated theropod teeth are one of the most common vertebrate fossils that have been found in the Khorat Group of Thailand. Furthermore, several isolated teeth have been discovered from the Upper Jurassic Phu Kradung Formation, located in Phu Noi locality of Kalasin Province, Northeastern Thailand. Three of those theropod teeth from the Phu Noi locality show unique dental features that can be distinguished from previous discovered metriacanthosaurid theropod, including the lateral teeth with mesiolingual twisted mesial carinae extending above the cervix line and braided enamel surface texture. Morphological examination with cladistics and morphometric analyses show that these isolated teeth exhibit the synapomorphies of basal tyrannosauroids, closely related to Guanlong wucaii and Proceratosaurus bradleyi from the Jurassic Period. This paper notes the first report of a basal tyrannosauroid in Southeast Asia as well as significantly contributes to our understanding of paleoecology of the Upper Jurassic Phu Kradung Formation and paleobiogeography of Tyrannosauroidea during the Jurassic Period.

Keywords: Dinosauria, Theropod, isolated teeth, Phu Kradung Formation, Mesozoic Era

Paleoenvironmental reconstruction of the Late Jurassic Phu Kradung Formation of Northeastern Thailand.

Illustrated by Chatcharin Somboon.

Wongwech Chowchuvech, Sita Manitkoon, Phornphen Chanthasit and Chatchalerm Ketwetsuriya. 2024. The First Occurrence of a Basal Tyrannosauroid in Southeast Asia: Dental Evidence from the Upper Jurassic of Northeastern Thailand. Tropical Natural History. 24(1); 84–95.   li01.tci-thaijo.org/index.php/tnh/article/view/261261

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Researchgate.net/publication/376029479_The_First_Occurrence_of_Tyrannosauroid_Dinosaur_in_Southeast_Asia

ค้นพบ ฟันไดโนเสาร์ไทแรนโนซอรอยด์ ญาติเก่าแก่ของ T. rex ยุคจูแรสซิกในประเทศไทย 🦖

...  ซากดึกดำบรรพ์ฟันไดโนเสาร์ไทแรนโนซอรอยด์แรกเริ่ม จากหมวดหินภูกระดึงตอนล่าง ยุคจูแรสซิกตอนปลาย ในแหล่งซากดึกดำบรรพ์ภูน้อย อำเภอคำม่วง จังหวัดกาฬสินธ์ุ ซึ่งเป็นหนึ่งในญาติเก่าแก่ของไดโนเสาร์กินเนื้อขนาดใหญ่ชื่อดังอย่างไทแรนโนซอรัส เร็กซ์ หรือ ที. เร็กซ์ ในยุคครีเทเชียสตอนปลาย ทวีปอเมริกาเหนือ ...

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[Paleontology • 2023] Giant Baleen Whales emerged from A Cold southern Cradle

Chaeomysticete mandible fragments NMV P218462 (Museums Victoria) from the Aquitanian–Burdigalian of South Australia.

in Rule, Duncan, Marx, Pollock, Evans & Fitzgerald, 2023.

 DOI: 10.1098/rspb.2023.2177

 twitter.com/Palaeo_JRule

Abstract

Baleen whales (mysticetes) include the largest animals on the Earth. How they achieved such gigantic sizes remains debated, with previous research focusing primarily on when mysticetes became large, rather than where. Here, we describe an edentulous baleen whale fossil (21.12–16.39 mega annum (Ma)) from South Australia. With an estimated body length of 9 m, it is the largest mysticete from the Early Miocene. Analysing body size through time shows that ancient baleen whales from the Southern Hemisphere were larger than their northern counterparts. This pattern seemingly persists for much of the Cenozoic, even though southern specimens contribute only 19% to the global mysticete fossil record. Our findings contrast with previous ideas of a single abrupt shift towards larger size during the Plio-Pleistocene, which we here interpret as a glacially driven Northern Hemisphere phenomenon. Our results highlight the importance of incorporating Southern Hemisphere fossils into macroevolutionary patterns, especially in light of the high productivity of Southern Ocean environments.

Keywords: Mysticeti, Chaeomysticeti, Southern Hemisphere, body size, gigantism

Systematic palaeontology

Cetacea Brisson 1762

Neoceti Fordyce & Muizon 2001

Mysticeti Gray 1864

Chaeomysticeti Mitchell 1989

Chaeomysticeti gen. et sp. indet.

Referred specimen. NMV P218462, symphyseal regions of both mandibles, plus fragments of the left premaxilla and maxilla.

Locality and horizon. NMV P218462 was found by F.A. Cudmore (on 15 February 1921) eroding from limestone cliffs on the east bank of the Murray River, opposite Wongulla, about 5 km south of Devon Downs, South Australia. ...

 

Conclusion: 

Baleen whales first evolved large body size in the Southern Hemisphere, perhaps facilitated by the onset of the ACC and high seasonal productivity in the Southern Ocean. Previous suggestions of an abrupt global Plio-Pleistocene shift towards mysticete gigantism are hampered by a strong collection bias against austral localities that obscures more gradual and regional trends. Medium-large mysticetes may have helped to engineer ocean ecosystems, albeit in a comparatively limited fashion, since the beginning of the Neogene. Further exploration of the Southern Hemisphere is crucial to constructing a truly global picture of the nature, timing and impacts of whale evolution.

James P. Rule, Ruairidh J. Duncan, Felix G. Marx, Tahlia I. Pollock, Alistair R. Evans† and Erich M.G. Fitzgerald. 2023. Giant Baleen Whales emerged from A Cold southern Cradle. Proc. R. Soc. B. 290: 20232177. DOI: 10.1098/rspb.2023.2177

 twitter.com/Palaeo_JRule/status/1737286061276242142

[PaleoIchthyology • 2023] An enigmatic large mawsoniid coelacanth (Sarcopterygii: Actinistia) from the Upper Jurassic Kimmeridge Clay Formation of England

  Mawsoniidae gen. et sp. indet. (MJML K785).

in Toriño, Gausden, Etches, Rankin, Marshall & Gostling, 2023. 

DOI: 10.1080/02724634.2022.2125813 

  twitter.com/PabloTorino4

  Researchgate.net/publication/364672796

(artwork by S. Gausden).

 

Abstract

A large mawsoniid coelacanth from the lower part of the marine Kimmeridge Clay Formation of England (Kimmeridgian, Upper Jurassic) is studied here. The material is constituted by a group of bones from the head and shoulder girdle of a considerably large individual (estimated length ca. 1.5 m), including the left angular, left dentary, left prearticular, left palatoquadrate complex, both ceratohyals and right cleithrum. Characters such as the coarse external ornamentation of the angular, and the robustness of the quadrate and the cleithrum allow classification of the individual as a member of the Mawsoniidae; whereas the configuration of external bones of the lower jaw (ornamentation of the angular constituted mainly by longitudinal ridges, the presence of a lateral swelling in the dentary) indicates stronger Gondwanan affinities than previously expected (i.e., with the genus Mawsonia, up to now only recorded in South America by the end of the Jurassic). Considering the above, two alternative evolutionary, paleobiogeographic, and taxonomic scenarios are discussed: (1) the new individual can be referred to the European mawsoniid genus Trachymetopon (Lower–Middle Jurassic), in which case it should be assumed this genus reached the Upper Jurassic, and with a morphological variability higher than previously suspected (including some characters previously assumed as diagnostic for Mawsonia). Or (2) an unknown Mawsonia-like form was present in the Upper Jurassic of Europe. The last scenario puts the identification of isolated elements of European Jurassic giant mawsoniids in a new complex taxonomic and paleobiogeographic context, which will deserve further research.

  

 

A, stratigraphic profile of the lower part of the Kimmeridge Clay Formation indicating the level where the material was collected (adapted from Gallois, 2020); B, photograph of the collecting site at Ringstead Bay (one of the authors –S. Etches– for scale).

  Mawsoniidae gen. et sp. indet. (MJML K785).
A, schematic anatomical restoration of the head in left lateral view, showing the preserved bones (missing gray parts based on Maisey 1986; Toriño et al., 2021a); B, hypothetical life restoration

(artwork by S. Gausden).

 A, map showing the geographic provenance of the material studied in this work; B, paleogeographic context during Kimmeridge Clay times, with special reference to Laurasian masses (based on the reconstructions of Cox, 2020 after Callomon, 1985; Thierry, 2000; Gallois, 2020; Stumpf et al., 2021)

  

 

 

Pablo Toriño, Shane F. Gausden, Steve Etches, Kathryn Rankin, John E. A. Marshall and Neil J. Gostling. 2023. An enigmatic large mawsoniid coelacanth (Sarcopterygii, Actinistia) from the Upper Jurassic Kimmeridge Clay Formation of England. Journal of Vertebrate Paleontology. 42(1);  e2125813. DOI: 10.1080/02724634.2022.2125813 

  twitter.com/PabloTorino4/status/1585261494916235265

 Researchgate.net/publication/364672796_An_enigmatic_large_mawsoniid_coelacanth_from_the_Upper_Jurassic_Kimmeridge_Clay_Formation_of_England

[Paleontology • 2023] The First Fossil Coelacanth from Thailand (Cretaceous, Phu Kradung Formation)

A left angular (PRC 160)

Mawsoniidae indeterminate

in Cavin, Tong, Buffetaut, Wongko, Suteethorn & Deesri, 2023. 

 DOI: 10.3390/d15020286 

Abstract

Mawsoniidae is a family of coelacanths restricted to the Mesozoic. During the Cretaceous, mawsoniids were mainly represented by the Mawsonia/Axelrodichthy complex, long known to be from western Gondwana only (South America and Africa). This apparent biogeographical distribution then faded following the discovery of representatives in the Late Cretaceous of Laurasia (Europe and North America). We report here the presence, in the Lower Cretaceous site of Kham Phok, NE Thailand, of an angular bone referred to the Mawsonia/Axelrodichthys complex. A comparison with angulars referring to both genera found in various regions of the world between the Late Jurassic and the Late Cretaceous indicated that the distinctions between these genera, and even more so between their constituent species, are unclear. This discovery is further confirmation of the very slow morphological evolution within this lineage, which may explain why their evolutionary history appears to be disconnected, at least in part, from their geographical distribution over time.

Keywords: Actinistia; Mawsoniidae; paleobiogeography; angular; Khorat Plateau; Early Cretaceous; Axelrodichthys; Mawsonia

 Systematic Paleontology

Actinistia Cope, 1871 

Latimerioidei Schultze, 1993 

Mawsoniidae Schultze, 1993  

Mawsoniidae indeterminate

Referred material: A left angular associated with a dermal skull bone (supraorbital?) (PRC 160) from the Kham Phok fossil site.

Locality and horizon: Kham Phok, Khamcha-i district, Mukdahan Province, upper part of the Phu Kradung Formation, basal Cretaceous.

 Comparison in labial (a–k) and lingual (a’–k’) views between left angular PRC 160, Kham Phok locality ((g), framed in red), and other angulars referred to the Mawsonia/Axelrodichthys complex, discovered in various parts of the world dated between the Late Jurassic and the Late Cretaceous (red spots). Remark: Specimens i and j, figured by Cupello et al. [2016] and Batista et al. [2019] are both from a formation called Missão Velha and Brejo Santo, respectively, with an uncertain age of the Late Jurassic or Late Cretaceous. (a) A. megadromos, Southern France, terminal Cretaceous (inverted); (b) M. sp., USA, Woodbine Fm. (inverted); (c), A. lavocati, Northern Africa, ‘Continental Intercalaire’; (d) A. araripensis, Brazil, Santana Fm. (inverted); (e) M. gigas, Brazil, Marfim Fm.; (f) M. gigas, Brazil, Sanfranciscana Fm. (inverted); (h) mawsoniid indet., UK, Kimmeridge Clay; (i) mawsoniid indet., Brazil, MissãoVelha/Brejo Santo Fm.; (j) M. gigas, Brazil, MissãoVelha/Brejo Santo Fm. (inverted); (k) M. gigas, Brazil, Taruarembó Fm. Data from Cavin et al. (2021). Orange spots indicate other mawsoniid remains, not detailed here. The main anatomical structures are figured with colored areas.

Abbreviations: a.f, adductor fossa (blue); con.Part, contact surface with prearticular (red); gr.VII.m.ext groove for external mandibular ramus of VII (green); l.f, longitudinal fossa (orange); m.s.c, mandibular sensory canal (yellow); sut.p.Co, sutural contact surface with principal coronoid (purple); sut.De: sutural surface for dentary (pink); sut.Spl: sutural surface for splenial (grey).

Conclusions: 

The discovery of a mawsoniid coelacanth in the Lower Cretaceous of Thailand is an important new addition to the already rich vertebrate assemblages of the Phu Kradung Formation and, more generally, the Jurassic–Early Cretaceous assemblages of the Khorat Group. On a global scale and on the scale of tens of millions of years, this new occurrence blurs the palaeobiogeographical model previously proposed for this clade. It questions both the vicariance and dispersal events previously proposed to explain the observed distribution. The recognition of the coelacanths as forming a slowly evolving clade, in particular the mawsoniid clade, can explain the disconnection between the phylogenetic pattern and the paleobiogeographical framework, whereas such a connection is normally expected in biogeographical studies. One way to test this scenario is (1) to attempt to build a stronger phylogeny based on a re-study of known and hopefully new material and (2) to better decipher the Cenozoic evolutionary history of the extant coelacanth, Latimeria, which shows a split of species between 30 and 40 million years ago associated with almost no morphological differentiation and therefore represents a good model to better understand the Cretaceous mawsoniid case.

 

 Lionel Cavin, Haiyan Tong, Eric Buffetaut, Kamonlak Wongko, Varavudh Suteethorn  and Uthumporn Deesri. 2023. The First Fossil Coelacanth from Thailand. Diversity. 15(2), 286. DOI: 10.3390/d15020286  (This article belongs to the Special Issue Evolution and Diversity of Fishes in Deep Time)