[Paleontology • 2026] Climate-extreme-driven Genesis of A Cretaceous Dinosaur Lagerstätte

 

 in Fanti, Consorti, Muscioni, Baldassari, Dinelli, Polentarutti, ... et Chiarenza. 2026. 

DOI: doi.org/10.1016/j.gloplacha.2026.105589 

 x.com/AAlechiarenza

Artwork by palaeoartist Davide Bonadonna

Highlights: 

• Monsoon-driven storms created a Cretaceous dinosaur Lagerstätte.

• Tidal microcouplets yield an unprecedented ∼40-year chronometry.

• Synchrotron micro-XRF/XRD maps refute seasonal varve interpretation.

• Microbial mats enabled rapid sealing and exceptional soft-tissue preservation.

• New genetic model and toolkit for climate event-driven preservation in carbonates.

Abstract

Konservat-Lagerstätten provide exceptional records of past ecosystems, yet the environmental and climatic processes governing their formation in extreme climatic regimes remain a significant, unresolved conundrum. Here we present a novel, process-based mechanism for the Villaggio del Pescatore Konservat-Lagerstätte (northeastern Italy; Late Cretaceous, 80 Ma), which preserves a diverse terrestrial and aquatic biota. Integrating high resolution synchrotron micro-analyses, bulk geochemistry, detailed taphonomy and palaeoclimate simulations we identify a dynamic, monsoon-paced tidal flat ecosystem within a carbonate coastal margin. Field and core records comprise metrescale packages of laterally persistent light–dark laminae; microstratigraphic, spectral and statistical analyses indicate a semidiurnal tidal regime with neap–spring modulation. MicroXRF/XRD mapping reveals that individual microlaminae within couplets share the same elemental inventory refuting a seasonal varve origin. Laminae chronometry, tied to the tidal interpretation, constrains net accumulation of the fossil bearing rhythmites to decadal (∼40 year) timescales. Geochemical proxies record alternating terrigenous rich, high TOC intervals and drier, better oxygenated intervals. Palaeoclimate model ensembles diagnose a vigorous, summer dominated monsoon domain at ∼29° N under greenhouse boundary conditions. We document that episodic monsoon enhanced flood and tropical cyclone pulses delivered sediment, nutrients, carcasses and plant debris to a microbially active, carbonate tidal flat; microbial mats rapidly stabilised and promoted early cementation, enabling exceptional soft tissue preservation. We propose a genetic model in which monsoon–cyclone forcing, tidal trapping and microbial sealing combine to produce decadal, daily resolved vertebrate Lagerstätten in greenhouse settings, offering predictive targets for similar deposits and deep time analogues for modern coastal change.

Keywords: Exceptional fossil preservation, Dinosauria, Crocodylomorpha, Arthropoda, Plants, Italy

“Stormbringer” — palaeoenvironmental reconstruction of Villaggio del Pescatore
The artwork shows a Tethyshadros insularis carcass and an Acynodon crocodylian on a storm-swept tropical tidal flat, beneath the monsoon clouds and a distant cyclone that the study identifies as the engine of the site’s formation.

 by palaeoartist Davide Bonadonna. 

 

Federico Fanti, Lorenzo Consorti, Marco Muscioni, Lorenzo Baldassari, Enrico Dinelli, Maurizio Polentarutti, Giorgio Bais, Alexander Farnsworth, Evelyn Kustatscher, Amalia Spina and Alfio Alessandro Chiarenza. 2026. Climate-extreme-driven Genesis of A Cretaceous Dinosaur Lagerstätte. Global and Planetary Change.  265, October 2026, 105589. DOI: doi.org/10.1016/j.gloplacha.2026.105589

 x.com/AAlechiarenza/status/2074802383733813269

[PaleoEntomology • 2024] Natator giganteus • A new giant Jurassic lacewing larva reveals a particular aquatic habit and its significance to the palaeoecology

 

Natator giganteus 

Kong, Shih, Ren & Wang, 2024

 

DOI: doi.org/10.1111/jse.13071

Abstract

Neuroptera, as a small relic group of Insecta undergoing a rapid species diversification during the Mesozoic Era, is known by diverse extinct endemic lineages preserved as impression fossils and in amber. The current understanding of Mesozoic neuropterans′ diversity has mainly focused on the adults, because the contemporaneous larvae have been fairly rare especially for the Jurassic lacewings. Herein, a new giant lacewing larva, Natator giganteus gen. et sp. nov., is described from the Middle Jurassic Daohugou Beds of China. The remarkable larva is characterized by its impressively large body size, distinctively elongated cervix, and presence of swimming hairs on legs, which provide direct evidence to reveal an aquatic habit for the Jurassic lacewing larva. The morphological analysis indicates this giant larva would have probably inhabited the benthic environments of Jurassic montane rivers and streams. In addition, its morphological specialization suggests that it might have adopted an ambush predation strategy to catch its prey. The finding enhances our knowledge of the species diversity and morphological plasticity for the Jurassic lacewing larvae, and reveals that the aquatic lineages of Neuroptera exhibited dramatically structural and ecological convergence across the evolutionary process.

Keywords: Daohugou bed, fossil, larvae, Middle Jurassic, Neuroptera, swimming hairs

Natator giganteus gen. et sp. nov.

Bowen Kong, Chungkun Shih, Dong Ren and Yongjie Wang. 2024. A new giant Jurassic lacewing larva reveals a particular aquatic habit and its significance to the palaeoecology. Journal of Systematics and Evolution. DOI: doi.org/10.1111/jse.13071  [21 April 2024]

https://www.jse.ac.cn/EN/10.1111/jse.13071

https://x.com/JournalSysEvo/status/1791154041839403090

 

[PaleoMammalogy • 2025] Yeutherium pressor • A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals

  

Yeutherium pressor

Püschel, Martinelli, Soto-Acuña, Ortiz, Leppe & Vargas, 2025

 

DOI: doi.org/10.1098/rspb.2025.1056

Artistic reconstruction by Mauricio Alvarez

Abstract

Mesozoic mammals from Gondwana remain poorly understood, with most species known only from isolated teeth. Nevertheless, these tantalizing fossils point to a diversity of families that were distinct from Laurasian forms. Among these, the enigmatic South American family Reigitheriidae was proposed based on the unique crushing teeth of its sole representative, Reigitherium, from Northern Patagonia. Here, we report a new mammal, Yeutherium pressor gen. et sp. nov., which is only the second known taxon of Reigitheriidae. This is based on a partial maxilla bearing an upper molar from the Late Cretaceous Dorotea Formation in the Río de Las Chinas valley, Sub-Antarctic Chile. Parsimony and Bayesian phylogenetic analyses indicate a close relationship between Reigitherium and Yeutherium. Shared features between both taxa—such as expanded preparacristae and postparacristae, a lingual cingulum at the paracone base, interradicular crests and enamel crenulations—help define Reigitheriidae. Cingula development and molar morphology of Yeutherium differ from that of the related Mesungulatidae, suggesting independent evolution of the crushing adaptations in Reigitheriidae. Additionally, we suggest a reinterpretation of the dental formula of Reigitheriidae. The discovery of Yeutherium highlights the specialized dentition of Reigitheriidae as a significant functional innovation in a radiation of Gondwanan mammals that is starting to be understood.

Keywords: Mammalia, Meridiolestida, Mesungulatoidea, Reigitheriidae, Patagonia, Cretaceous

Yeutherium pressor gen. et sp. nov.

Hans P. Püschel, Agustin G. Martinelli, Sergio Soto-Acuña, Héctor Ortiz, Marcelo Leppe and Alexander O. Vargas. 2025. A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals. Proc. R. Soc. B. 292: 20251056. DOI: doi.org/10.1098/rspb.2025.1056 [06 August 2025]

https://x.com/PuschelHans/status/1952915559588229455

[Paleontology • 2024] Eoactinotocarcinus n. gen. & Tumulosternum ortegai n. sp. • New Spider Crabs (Brachyura: Majoidea) from the early Eocene of Spain with A Reassignment of the Species “Periacanthus” tetracornis

Tumulosternum ortegai Ferratges, 2024

Eoactinotocarcinus n. gen.

 Eoactinotocarcinus tetracornis

(Ferratges, Ortega, Fernández, Moreno & Maza, 2014)

in Ferratges, 2024

DOI: doi.org/10.1344/GeologicaActa2024.22.12 

Abstract

Spider crabs (superfamily Majoidea Samouelle, 1819) represent a highly diverse group within Eubrachyura de Saint Laurent, 1980. This study re-examines the species “Periacanthus” tetracornis Ferratges, Ortega Fernández, Moreno and Maza, 2014 (Roda Formation, lower Eocene of Spain) which was previously consider as a member of Epialtidae MacLeay, 1838 and it is included as a new genus of majoid crabs, Eoactinotocarcinu n. gen. Additionally, Tumulosternum ortegai n. sp. is described from the same geological unit expanding the distribution of this genus to the southern Pyrenees. These taxa were found in siliciclastic facies co-occurring with a diverse assemblage of decapod crustaceans and other invertebrates. These facies are interpreted as deposited in a prodelta environment supporting the idea of such environments as highly diversified areas of decapods during the Eocene. These new taxa represent the earliest known record of the Subfamily Actinotocarcininae Jenkins, 1974 and the genus Tumulosternum respectively.

Keywords: Malacostraca, Decapoda, benthonic, taxonomy, Ypresian

Tumulosternum ortegai 

 Eoactinotocarcinus tetracornis 

Fernando Ari Ferratges. 2024. New Spider Crabs (Brachyura, Majoidea) from the early Eocene of Spain with A Reassignment of the Species “Periacanthus” tetracornis. Geologica Acta. 22.12, 1-13, I-II.

DOI: doi.org/10.1344/GeologicaActa2024.22.12 

Un nuevo género y una nueva especie de cangrejos araña en el Pirineo Aragonés

https://www.aragosaurus.com/un-nuevo-genero-y-una-nueva-especie-de-cangrejos-arana-en-el-pirineo-aragones 

[PaleoMammalogy • 2025] Novaculadon mirabilis • A new multituberculate (Mammalia: Allotheria: Plagiaulacidae) from the Lulworth Formation (Cretaceous, Berriasian) of Dorset, England

 

Novaculadon mirabilis  

Weston, Sweetman, Kean, Wood, Martill & Smith, 2025

DOI: doi.org/10.1016/j.pgeola.2025.101128

Abstract

A new genus and species of plagiaulacid multituberculate (Mammalia, Allotheria, Multituberculata) is described from the Cherty Freshwater Beds, Warbarrow Tout Member of the Lower Cretaceous Lulworth Formation of the Purbeck Group, Dorset, United Kingdom. The new taxon is represented by a complete, well preserved left dentary containing the incisor, p2–4, with alveoli for m1–2. This new specimen is the most complete multituberculate material yet recovered from the Purbeck Group. It is also the first mammal to be recovered from the so-called ‘Flint Bed’ (DB97).

Keywords: Mammalia, Multituberculata, Early Cretaceous, Purbeck Group, United Kingdom

 Holotype left dentary of Novaculadon mirabilis gen. et sp. nov. NHMUK PV M 119716 from the Lulworth Formation, Purbeck Group at Durlston Bay.
In: A, buccal view; and B, lingual view. Scale bar represents 5 mm.

 Images of 3D model generated from XCT scans of the holotype left dentary of Novaculadon mirabilis gen. et sp. nov. NHMUK PV M 119716 from the Lulworth Formation, Purbeck Group at Durlston Bay.
In: A, buccal view; B, lingual view; C, occlusal view; D, ventral view; E, anterior view; and F, posterior view. Scale bar represents 5 mm.

 Systematic palaeontology

Mammalia Linnaeus, 1758

Allotheria Marsh, 1880

Multituberculata Cope, 1884

Plagiaulacida Simpson, 1925 (nomen correctum McKenna, 1971 ex Plagiaulacoidea, Ameghino, 1889)

Plagiaulacoidea Hahn and Hahn, 2004

Plagiaulacidae Gill, 1872 (synonym: Bolodontidae Osborn, 1887)

Novaculadon gen. nov.

Etymology. From the Latin novācula, razor, and don, from the Greek οδóς (odós) meaning teeth. Pertaining to the sharp occlusal crest formed by the premolar series.

 

Novaculadon mirabilis gen. et sp. nov.

Etymology. From the Latin mīrābilis, miraculous. An allusion to the exceptional preservation of the holotype.

  Artist’s restoration of Novaculadon mirabilis gen. et sp. nov.

Artwork by Hamzah Imran.

 

Benjamin T. Weston, Steven C. Sweetman, Jake Kean, Charles Wood, David M. Martill and Roy E. Smith. 2025. A new multituberculate (Mammalia, Allotheria) from the Lulworth Formation (Cretaceous, Berriasian) of Dorset, England. Proceedings of the Geologists' Association. In Press, 101128. DOI: doi.org/10.1016/j.pgeola.2025.101128 [9 July 2025]

 

[Paleontology • 2025] Diverse Dinosaur Tracks from the Upper Jurassic – Lower Cretaceous Chacarilla Formation of Quebrada de Arcas, northeast Chile: Evidence of high ichnodiversity in an arid palaeoenviroment

 

 Paleoartistic reconstruction of the Quebrada de Arcas. 

in Gesualdi, Belvedere, Yurac, ... et Meyer, 2025. 

DOI: doi.org/10.1016/j.palaeo.2025.113088

Illustration by Joschua Knüppe.

 

Highlights: 

• New track-bearing surfaces are found in the Chacarilla Fm. in Quebrada des Arca.

• Five morphotypes: one of sauropod and four for different size theropod tracks are defined.

• Huge theropod tracks have been found and identified.

Abstract

We report diverse dinosaur tracks from siltstone to fine-grained sandstone facies of the Chacarilla Formation, Quebrada de Arcas of northeast Chile. Track-bearing surfaces were studied using 3D modelling and false-colour depth maps, derived from UAV photographs. Five morphotypes are identified based on morphology and morphometric criteria. Morphotype I comprises rounded tracks with a consistent narrow-gauge and resembles the sauropod ichnogenus, Parabrontopodus; diplodocids or titanosaurids are probable trackmakers. Morphotype II is assigned to the theropod ichnotaxon Abelichnus astigerrae and comprises some of the largest theropod tracks ever recorded from South America with a maximum footprint length of 51 cm; the trackmaker was most likely a large carcharodontosaurid, such as Giganotosaurus carolinii. Morphotype III is an indeterminate theropod track, which shows a distinctive and prominent metatarsal impression, but does not closely match any ichnotaxon although it bears some morphometrical affinity to Changpeipus carbonicus. The Morphotypes IV and V both belong to small-sized theropod trackmakers, and resemble Grallatoridae and Kayentapus-like forms, respectively. Additional theropod material cannot be assigned to specific morphotypes or trackmakers, due to poor preservation. Our findings show the existence of three distinct size classes (small, medium and large) of theropod morphotypes and point to a high ichnodiversity at the Jurassic-Cretaceous transition in the subtropical arid environments of Gondwana.

Keywords: Dinosaur tracks, Abelichnus astigerrae, Chacarilla Formation, Gondwana, Jurassic-Cretaceous boundary

 Sedimentary structures in the Chacarilla Fm. Ripple marks (a, d, e), planar lamination (a, c), microbial mats from surface QA12 (b), Ophiomorpha (f) and cross-section dinosaur tracks (c).

Scale bars are: 50 cm in (a), 18 cm in (b), 25 cm in (c), 10 cm in (d, e, f).

 Paleoartistic reconstruction of the Quebrada de Arcas.

 Illustration by Joschua Knüppe.

 

Vincenzo Gesualdi, Matteo Belvedere, Marko Yurac, Dorothee Hippler, Nejla Hurem, Christian Salazar, Javiera Mendez and Christian A. Meyer. 2025. Diverse Dinosaur Tracks from the Upper Jurassic – Lower Cretaceous Chacarilla Formation of Quebrada de Arcas, northeast Chile: Evidence of high ichnodiversity in an arid palaeoenviroment. Palaeogeography, Palaeoclimatology, Palaeoecology. 113088; In Press. DOI: doi.org/10.1016/j.palaeo.2025.113088 [9 June 2025]

[Paleontology • 2025] Isolated theropod teeth from the Upper Jurassic to Lower Cretaceous Khorat Group: Implications for Theropod Diversity in Thailand

Isolated theropod teeth from the Upper Jurassic to Lower Cretaceous Khorat Group 

in Chowchuvech, Manitkoon, Chanthasit, Chokchaloemwong, Kosulawatha et Ketwetsuriya, 2025.   

DOI: doi.org/10.1016/j.cretres.2025.106147 

facebook.com: Job Wongwech 

 

Abstract

Isolated theropod teeth are notably abundant of vertebrate remains within the Upper Jurassic to Lower Cretaceous Khorat Group of Thailand. However, despite the discovery of numerous dental materials, only a limited number of studies have focused on the morphology and taxonomy of these isolated teeth. This study investigated 112 isolated theropod teeth were retrieved from 19 localities on the Khorat Plateau in Northeastern Thailand. These teeth were divided into five morphotypes based on dental characteristics. They were identified based on cladistic and discriminant analyses that recovered four clades of theropod dinosaurs: Metriacanthosauridae, Tyrannosauroidea, Spinosauridae, and Allosauria. This dental evidence provide significant insights into the theropod diversity in Thailand during the Late Jurassic to Early Cretaceous. Specifically, the Late Jurassic to Early Cretaceous Phu Kradung Formation revealed an extended presence of metriacanthosaurids and basal tyrannosauroids, while the Sao Khua and Khok Kruat Formations indicated a shift towards allosaurian and spinosaurid dominance during the Early Cretaceous. The absence of metriacanthosaurids and basal tyrannosauroids in later formations suggests a faunal turnover, with allosaurians and spinosaurids becoming more prevalent, aligning with the changes in theropod faunal composition across Eurasia. Furthermore, this contribution suggested the faunal turnover pattern in the Eurasian theropods during the Jurassic-Cretaceous boundary interval, which might have been related to the change in herbivorous dinosaurs during this crucial timeframe of dinosaur evolution.

Wongwech Chowchuvech, Sita Manitkoon, Phornphen Chanthasit, Duangsuda Chokchaloemwong, Wachirawit Kosulawatha and Chatchalerm Ketwetsuriya. 2025.  Isolated theropod teeth from the Upper Jurassic to Lower Cretaceous Khorat Group: Implications for theropod diversity in Thailand. Cretaceous Research. 175, 106147. DOI: doi.org/10.1016/j.cretres.2025.106147

  facebook.com/JobjabChowchuvech/posts/10091230104273775

[PaleoMammalogy • 2025] Cambelodon torreensis • A New pinheirodontid multituberculate from the Upper Jurassic of western Portugal

 

Cambelodon torreensis

Carvalho, Camilo, Araújo, Castro, Kullberg, Desmet, Nerinckx, Leite & Reis, 2025

DOI: doi.org/10.1002/spp2.70012

 

Abstract

Cambelodon torreensis gen. et sp. nov. is described based on a recently discovered, well-preserved right hemimandible of a pinheirodontid multituberculate from the Upper Jurassic (Tithonian) Freixial Formation at the Ulsa quarry, Cambelas, Portugal. This discovery marks a pivotal advancement in understanding the anatomy of Pinheirodontidae, a family previously known only from isolated teeth. Cambelodon torreensis has a distinctive suite of morphological characteristics, including high-crowned premolars with prominent subtriangular lobes, an elongated diastema, a well-developed masseteric fossa, and a large complement of basal cusps on the fourth lower premolar. Notably, it may have had a non-sequential posteroanterior tooth replacement, a pattern previously documented only in paulchoffatiids from the Oxfordian and Kimmeridgian. This finding extends the temporal range of this dental developmental trait to include late Tithonian multituberculates, providing new insights into the dental evolution of early mammals. Geological and palynological analyses of productive sites at the Freixial Fm. suggest a low-energy depositional environment with periodic soil formation in an arid or semi-arid palaeoclimate. The composition and taphonomy of the bonebed, which contains both macrofossils and microfossils, indicate a mud-entrapment episode. Parsimony-based phylogenetic analysis confirms the placement of Cambelodon torreensis in Pinheirodontidae, validating this family as a distinct and monophyletic group within multituberculates. This research fills gaps in our knowledge of the early multituberculate fossil record and provides insights into the ecological dynamics that shaped the ancient environments of the Iberian Peninsula.

Keywords: Multituberculata, Pinheirodontidae, tooth replacement, Lusitanian Basin, Tithonian, palaeoenvironment

 The image shows a fossil jawbone (SHN.830) from both outer (lateral) and inner (medial) sides.
3D model showing unerrupted incisor.

Scale bar is 2 mm.  

Cambelodon torreensis gen. et sp. nov.

Victor F. Carvalho, Bruno Camilo, Ricardo Araújo, Lígia Castro, José C. Kullberg, Hilde G. B. Desmet, Ignace Nerinckx, Marco Leite and Diego Reis. 2025. Cambelodon torreensis, a new pinheirodontid multituberculate from the Upper Jurassic of western Portugal. Papers in Palaeontology. 11(2); e70012. DOI: doi.org/10.1002/spp2.70012 [10 April 2025]

https://x.com/raraujopaleo/status/1910304976078790945

[PaleoOrnithology • 2024] Navaornis hestiae • Cretaceous Bird from Brazil informs the Evolution of the Avian Skull and Brain

Navaornis hestiae 

Chiappe, Navalón, Martinelli, Carvalho, Santucci, Wu & Field, 2024

 

 DOI: doi.org/10.1038/s41586-024-08114-4

Abstract

A dearth of Mesozoic-aged, three-dimensional fossils hinders understanding of the origin of the distinctive skull and brain of modern (crown) birds. Here we report Navaornis hestiae gen. et sp. nov., an exquisitely preserved fossil species from the Late Cretaceous of Brazil. The skull of Navaornis is toothless and large-eyed, with a vaulted cranium closely resembling the condition in crown birds; however, phylogenetic analyses recover Navaornis in Enantiornithes, a highly diverse clade of Mesozoic stem birds. Despite an overall geometry quantitatively indistinguishable from crown birds, the skull of Navaornis retains numerous plesiomorphies including a maxilla-dominated rostrum, an akinetic palate, a diapsid temporal configuration, a small cerebellum and a weakly expanded telencephalon. These archaic neurocranial traits are combined with a crown bird-like degree of brain flexion and a bony labyrinth comparable in shape to those of many crown birds but substantially larger. Altogether, the emergent cranial geometry of Navaornis shows an unprecedented degree of similarity between crown birds and enantiornithines, groups last sharing a common ancestor more than 130 million years ago. Navaornis provides long-sought insight into the detailed cranial and endocranial morphology of stem birds phylogenetically crownward of Archaeopteryx, clarifying the pattern and timing by which the distinctive neuroanatomy of living birds was assembled.

Systematic palaeontology

Aves Linnaeus, 1758

Ornithothoraces Chiappe and Calvo, 1994

Enantiornithes Walker, 1981

Navaornis hestiae gen. et sp. nov.

Remarks. We use Aves to refer to all taxa descended from the most recent common ancestor of Archaeopteryx lithographica and crown birds. 

Diagnosis. Enantiornithine with a toothless skull and a combination of the following features: fully fused premaxillae with a convex dorsorostral surface, highly curved jugal, small, comma-shaped quadratojugal, diminutive lacrimal failing to separate the orbit from the antorbital fenestra, parasphenoidal rostrum perforated by a large ovoid fenestra, elongate basipterygoid processes, large and sinusoidal anterior semicircular canal excavating the dorsal margin of the supraoccipital, robust and prominent medial process of the mandible.

Etymology. Navaornis honours William Nava, who discovered the fossil locality in 2004 and the holotype specimen in 2016; the specific epithet hestiae alludes to Hestia, the Greek goddess of architecture, regarded as simultaneously the oldest and the youngest of the Twelve Olympians. Navaornis reflects this duality in that it belongs to an archaic lineage, yet its cranial geometry is essentially modern. 

Luis M. Chiappe, Guillermo Navalón, Agustín G. Martinelli, Ismar de Souza Carvalho, Rodrigo Miloni Santucci, Yun-Hsin Wu and Daniel J. Field. 2024. Cretaceous Bird from Brazil informs the Evolution of the Avian Skull and Brain. Nature. 635, 376–381. DOI: doi.org/10.1038/s41586-024-08114-4

 

[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

[Paleontology • 2024] Extremely rapid, yet noncatastrophic, Preservation of the Flattened-feathered and 3D Dinosaurs of the Early Cretaceous of China

  

 Extremely rapid preservation of the flattened-feathered and 3D Dinosaurs of the Early Cretaceous, Yixian Formation in China

in MacLennan, Sha, Olsen, Kinney, Chang, Fang, Liu, Slibeck, Chen et Schoene, 2024.

DOI: doi.org/10.1073/pnas.2322875121

Significance: 

Traditionally, the spectacular preservation of fossils of feathered dinosaurs and early birds and other animals found in sedimentary strata of the Yixian Formation in northeast China has been attributed to Pompeii-like volcanic catastrophes. We provide high-resolution geochronology and sedimentological analysis challenging this model and show that these strata instead record normal life and death processes preserved in a succession of depositional environments that span less than 100 thousand years.

Abstract

Northeast China’s Early Cretaceous Yixian Formation preserves spectacular fossils that have proved extraordinarily important in testing evolutionary hypotheses involving the origin of birds and the distribution of feathers among nonavian dinosaurs. These fossils occur either flattened with soft tissue preservation (including feathers and color) in laminated lacustrine strata or as three-dimensional (3D) skeletons in “life-like” postures in more massive deposits. The relationships of these deposits to each other, their absolute ages, and the origin of the extraordinary fossil preservation have been vigorously debated for nearly a half century, with the prevailing view being that preservation was linked to violent volcanic eruptions or lahars, similar to processes that preserved human remains at Pompeii. We present high-precision zircon U-Pb geochronology from cores and outcrops, demonstrating that Yixian Formation accumulation rates are more than an order of magnitude higher than usually estimated. Additionally, we provide zircon provenance and sedimentological data from 3D dinosaur fossils, which imply that their death and burial occurred in collapsed burrows, rather than via a catastrophic volcanogenic mechanism. In the studied area, the three principal fossil-rich intervals of the Yixian occur as a cyclic sequence that correspond to periods of high precipitation. Using Bayesian–Markov Chain Monte Carlo approaches, we constrain the total duration of the sequence to less than ~93,000 y and suggest that climatic precession paced the expression of these cyclic sediments. Rather than representing multiple, Pompeii-like catastrophes, the Yixian Formation is instead a brief snapshot of normal life and death in an Early Cretaceous continental community.

Two perfectly articulated skeletons of the sheep-size dinosaur Psittacosaurus, found in China's Yixian Formation. New research suggests they died in burrow collapses, not via volcanism, as previously thought.

by Jun Liu, IVPP, Chinese Academy of Sciences

Artist's rendition of a Psittacosaurus dinosaur with babies being hunted by Repenomamus, a mammal. One fossil assemblage from the Yixian Formation preserved the remains of these species in mortal combat, frozen in mid-action. The dinosaur here is shown with bristly proto-feathers on its tail.

artwork by Alex Boersma

 Scott A. MacLennan, Jingeng Sha, Paul E. Olsen, Sean T. Kinney, Clara Chang, Yanan Fang, Jun Liu, Bennett B. Slibeck, Elaine Chen, and Blair Schoene. 2024. Extremely rapid, yet noncatastrophic, Preservation of the Flattened-feathered and 3D Dinosaurs of the Early Cretaceous of China. PNAS. 121 (47) e2322875121. DOI: doi.org/10.1073/pnas.2322875121

[Paleontology • 2024] Hand and Foot Morphology Maps Invasion of Terrestrial Environments by Pterosaurs in the mid-Mesozoic

 Scaphognathus crassirostris (Goldfuss, 1831) 

in Smyth, Breithaupt, Butler, Falkingham et Unwin, 2024. 

DOI: 10.1016/j.cub.2024.09.014

Paleoart by Rudolf Hima.

Highlights

• The hands and feet of pterosaurs were adapted to a broad range of locomotor ecologies

• Early pterosaurs had a scansorial mode of life, which restricted maximum body size

• Anatomical changes in later pterosaurs led to more effective terrestrial ability

• Invasion of terrestrial habitats facilitated diverse feeding ecologies and gigantism

Summary

Pterosaurs, the first true flying vertebrates, played a crucial role in Mesozoic terrestrial ecosystems. However, our understanding of their ability to move around on the ground and, more broadly, their terrestrial paleoecology remains limited. Here, we demonstrate an unexpectedly high degree of variation in the hands and feet of pterosaurs, comparable with that observed in extant birds. This suggests that pterosaurs were adapted to a remarkably broad range of non-aerial locomotor ecologies. Small, early, long-tailed pterosaurs (non-pterodactyliforms) exhibit extreme modifications in their hand and foot proportions indicative of climbing lifestyles. By contrast, the hands and feet of later, short-tailed pterosaurs (pterodactyliforms) typically exhibit morphologies consistent with more ground-based locomotor ecologies. These changes in proportions correlate with other modifications to pterosaur anatomy, critically, the separation along the midline of the flight membrane (cruropatagium) that linked the hindlimbs, enabling a much more effective locomotory ability on the ground. Together, these changes map a significant event in tetrapod evolution: a mid-Mesozoic colonization of terrestrial environments by short-tailed pterosaurs. This transition to predominantly ground-based locomotor ecologies did not occur as a single event coinciding with the origin of short-tailed forms but evolved independently within each of the four principal radiations: euctenochasmatians, ornithocheiroids, dsungaripteroids, and azhdarchoids. Invasion of terrestrial environments by pterosaurs facilitated the evolution of a wide range of novel feeding ecologies, while the freedom from limitations imposed by climbing permitted an increase in body size, ultimately enabling the evolution of gigantism in multiple lineages.

Keywords: Mesozoic, Pterosauria, adaptive radiation, manus, pes, ecomorphology, locomotor ecology, arboreal, scansorial, terrestrial

Paleoart reconstruction of the non-pterodactyliform Scaphognathus crassirostris (Upper Jurassic) in scansorial mode

Paleoart by Rudolf Hima.

Paleoart reconstruction of the pterodactyliform Balaenognathus maeuseri (Upper Jurassic) in terrestrial mode

Paleoart by Rudolf Hima.

Comparison of autopodial and other anatomical differences between non-pterodactyliform (scaphognathine) and pterodactyliform pterosaurs (derived ctenochasmatoid)
(A) Paleoart reconstruction of the non-pterodactyliform Scaphognathus crassirostris (Upper Jurassic) in scansorial mode, with autopodia characterized by short proximal elements and elongated distal elements.
(B) Paleoart reconstruction of the pterodactyliform Balaenognathus maeuseri (Upper Jurassic) in terrestrial mode, with autopodia characterized by elongated proximal elements and shortened distal elements.
(C) Reconstructions of Scaphognathus (left) and Balaenognathus (right) in dorsal view indicating the principal flight surfaces.
(D) Simplified pterosaur phylogeny indicating the principal taxonomic groups used in this study.

Abbreviations: bp, brachiopatagium; cp, cruropatagium; pp, propatagium. 

Paleoart by Rudolf Hima.

Robert S.H. Smyth, Brent H. Breithaupt, Richard J. Butler, Peter L. Falkingham and David M. Unwin. 2024. Hand and Foot Morphology Maps Invasion of Terrestrial Environments by Pterosaurs in the mid-Mesozoic. Current Biology. DOI: doi.org/10.1016/j.cub.2024.09.014