[Paleontology • 2025] Evolutionary and Paleobiogeographic Implications of New carcharodontosaurian, megaraptorid, and unenlagiine Theropod Remains from the upper Lower Cretaceous of Victoria, southeast Australia

 

Cretaceous Australia Landscape
 

in Kotevski, Duncan, Ziegler, Bevitt, Vickers-Rich, Rich, Evans & Poropat, 2025. 

DOI: doi.org/10.1080/02724634.2024.2441903  

artwork by Jonathan Metzger

ABSTRACT

The Early Cretaceous non-avian theropod body fossil record of Victoria, Australia dominantly comprises isolated dental and postcranial remains. Numerous specimens have been collected from both the upper Strzelecki Group (upper Barremian–lower Aptian) and Eumeralla Formation (upper Aptian–lower Albian), yet theropod diversity in each unit remains poorly resolved. In both deposits, specimens pertaining to Megaraptoridae—a clade seemingly endemic to South America and Australia in the Cretaceous—are most frequently encountered. However, evidence of other typically common Gondwanan theropod groups, including Abelisauridae and Carcharodontosauria, has remained unknown. Herein, we describe five new theropod specimens: three tibiae, and two articulated caudal vertebrae with haemal arches, from the upper Strzelecki Group; and a single tibia from the Eumeralla Formation. Two of these tibiae—one each from the upper Strzelecki Group and the Eumeralla Formation—provide the first evidence for Carcharodontosauria in Australia. Two megaraptorid specimens from the upper Strzelecki Group—a tibia, and two caudal vertebrae with haemal arches—demonstrate that this clade had achieved large body size at the time of its first appearance in the fossil record. A tibia from the upper Strzelecki Group is interpreted to represent the Gondwanan dromaeosaur clade Unenlagiinae. Collectively, the new theropod remains described herein strengthen the evidence for mid-Cretaceous faunal interchange between Australia and South America across Antarctica, and highlight the presence of carcharodontosaurians and unenlagiines at high latitudes in the late Early Cretaceous.

Carcharodontosauria indet. right tibia (NMV P221042)
from the Eumeralla Formation of Victoria, Australia.  

Cretaceous Australia Landscape.

artwork by Jonathan Metzger, Museums Victoria

Jake Kotevski, Ruairidh J. Duncan, Tim Ziegler, Joseph J. Bevitt, Patricia Vickers-Rich, Thomas H. Rich, Alistair R. Evans and Stephen F. Poropat. 2025. Evolutionary and Paleobiogeographic Implications of New carcharodontosaurian, megaraptorid, and unenlagiine Theropod Remains from the upper Lower Cretaceous of Victoria, southeast Australia. Journal of Vertebrate Paleontology. e2441903. DOI: doi.org/10.1080/02724634.2024.2441903  

[Paleontology • 2024] Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina

Myobradypterygius hauthali von Huene, 1927

in Pardo-Pérez, Zambrano, Malkowski, Lomax, Villa-Martínez, Stinnesbeck, Frey, Scapini, Gascó et Maxwell, 2024. 

DOI: 10.1093/zoolinnean/zlae106 

 facebook.com/DeanRLomax

 

Abstract

Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute to clarifying questions regarding ichthyosaur taxonomy and the palaeobiogeographical relationships between the southern Gondwanan and Northern Hemisphere ichthyosaur groups during the Early Cretaceous. Here, we describe three new ichthyosaur specimens from this locality. Two of them are referred to Myobradypterygius hauthali, expanding the distribution of this species from the Barremian of Argentina to the Hauterivian of the Chilean Patagonia. This material shows that M. hauthali differs from Platypterygius platydactylus in forefin construction and scapular morphology, supporting its classification as a separate genus within Platypterygiinae. The third specimen is a large-bodied indeterminate ophthalmosaurine ichthyosaur. This record represents the southernmost record of Ophthalmosaurinae and the first occurrence of this group from the Cretaceous of the Southern Hemisphere. These discoveries show that ophthalmosaurines and platypterygiines continued to occur sympatrically in southernmost Gondwana during the Early Cretaceous, expanding the pattern documented in Europe to the Pacific region.

Ichthyosauria, Early Cretaceous, Gondwana, Patagonia

Judith Pardo-Pérez, Patricio Zambrano, Matthew Malkowski, Dean Lomax, Rodrigo Villa-Martínez, Wolfgang Stinnesbeck, Eberhard Frey, Francisca Scapini, Cristina Gascó and Erin E Maxwell. 2024. Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina. Zoological Journal of the Linnean Society. 202(2); zlae106. DOI: doi.org/10.1093/zoolinnean/zlae106

  facebook.com/DeanRLomax/posts/1065943665536603

https://archiv.ub.uni-heidelberg.de/volltextserver/20000/

[Paleontology • 2025] Gondwanax paraisensis • A New “silesaurid” from the oldest Dinosauromorph-bearing Beds of South America provides insights into the early Evolution of Bird-line Archosaurs

Gondwanax paraisensis 

Müller, 2024  

DOI: 10.1016/j.gr.2024.09.007

Highlights: 

• One of the oldest dinosauromorphs is described.

• It is the earliest “silesaurid” with a sacrum composed of three vertebrae.

• The oldest episode of sympatry among “silesaurids” in South America is reported.

Abstract

Investigations regarding the early evolutionary history of bird-line archosaurs have undergone significant advancements in recent years. However, controversies remain, especially regarding the phylogenetic position of “silesaurids”. Whereas some hypotheses place these archosaurs as the sister-group to dinosaurs, others suggest that “silesaurids” are early ornithischian dinosaurs. Despite the phylogenetic disputes, “silesaurids” are a crucial group for comprehending the origins and early evolution of dinosaurs. In the present study, a new “silesaurid” from the Middle-Upper Triassic of Southern Brazil is described. Gondwanax paraisensis gen. et sp. nov. comes from the Dinodontosaurus Assemblage Zone of the Santa Maria Formation (Ladinian-Carnian boundary), representing one of the oldest “silesaurids” worldwide. Furthermore, Gondwanax paraisensis gen. et sp. nov is the oldest “silesaurid” with three sacral vertebrae, a feature usually observed in more derived forms. In addition, distinct from any other Triassic Pan-Aves, the new taxon bears an incipient fourth trochanter of the femur. This unique combination of features indicates a high diversity of locomotor strategies among early pan-avians. In addition, the co-occurrence of Gondwanax paraisensis gen. et sp. nov. and Gamatavus antiquus in the same Assemblage Zone represents the oldest evidence of sympatry among “silesaurids” in South America. Indeed, the unique combination of sacral and hindlimb features may suggest distinct behaviors for these species, potentially leading to niche differentiation within the same ecosystems.

Systematic palaeontology

Archosauria Cope, 1870 (sensu Gauthier & Padian, 2020)

Pan-Aves Gauthier and De Queiroz, 2001 (sensu Ezcurra et al., 2020)

Dinosauromorpha Benton, 1985 (sensu Ezcurra et al., 2020)

Gondwanax paraisensis gen. et sp. nov.

 

Rodrigo Temp Müller. 2024. A New “silesaurid” from the oldest Dinosauromorph-bearing Beds of South America provides insights into the early Evolution of Bird-line Archosaurs. Gondwana Research. In Press,  DOI: doi.org/10.1016/j.gr.2024.09.007

 

[Paleontology • 2024] Campananeyen fragilissimus • They all floated in the Cretaceous: New rebbachisaurid (Sauropoda: Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina

 

 Campananeyen fragilissimus

 Lerzo, Fernández-Baldor, Canale, Whitlock, Otero & Gallina, 2024

DOI: 10.1080/08912963.2024.2383708  

  facebook.com/LucasLerzo

ABSTRACT

Rebbachisaurids are a group of basal diplodocoid sauropods that diversified primarily in Gondwana between the early Lower Cretaceous and the early Upper Cretaceous. Their phylogenetic relationships are still under debate given the fragmentary and incomplete nature of its remains. Here, we provide a detailed description of the postcranial remains of Campananeyen fragilissimus gen. et sp. nov. from the Candeleros Formation (lower Cenomanian) of Neuquén Province, Argentina. Campananeyen presents notable features that allow it to be recognised as a new species by the presence of an underdeveloped crista prootica, paraoccipital process internally hollow and a fuse dorsal alar arm of the ilium. The phylogenetic analysis recovered this taxon as a basal rebbachisaurid closely related to Zapalasaurus, Sidersaura and the specimen from La Amarga Formation MACN-Pv-N 35. The new rebbachisaurid is recovered as the sister taxon of Sidersaura due the presence of procoelous posterior caudal vertebrae and dorsoventrally flattened posterior caudal centra. C. fragilissimus presents an extreme pneumatization of the sacral region with an autapomorphic dorsal alar arm of the sacral transverse processes. Finally, the phylogenetic analysis supports a South American origin for Rebbachisauridae and an early diversification to Africa and Europe by the Barremian-Aptian as previously suggested.

KEYWORDS: Candeleros formation, Dinosauria, Pneumatization, Gondwana, Campananeyen, Rebbachisauridae

Campananeyen fragilissimus gen. et sp. nov. 

 

Lucas N. Lerzo, Fidel Torcida Fernández-Baldor, Juan I. Canale, John A. Whitlock, Alejandro Otero and Pablo A. Gallina. 2024. They all floated in the Cretaceous: New rebbachisaurid (Sauropoda, Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina. Historical Biology: An International Journal of Paleobiology. DOI: doi.org/10.1080/08912963.2024.2383708  

  facebook.com/LucasLerzo/posts/10232910661419069

[Paleontology • 2024] Gaiasia jennyae • Giant stem Tetrapod was Apex Predator in Gondwanan late Palaeozoic Ice Age

  

Gaiasia jennyae

Marsicano, Pardo, Smith, Mancuso, Gaetano & Mocke, 2024

DOI: 10.1038/s41586-024-07572-0

Abstract

Current hypotheses of early tetrapod evolution posit close ecological and biogeographic ties to the extensive coal-producing wetlands of the Carboniferous palaeoequator with rapid replacement of archaic tetrapod groups by relatives of modern amniotes and lissamphibians in the late Carboniferous (about 307 million years ago). These hypotheses draw on a tetrapod fossil record that is almost entirely restricted to palaeoequatorial Pangea (Laurussia). Here we describe a new giant stem tetrapod, Gaiasia jennyae, from high-palaeolatitude (about 55° S) early Permian-aged (about 280 million years ago) deposits in Namibia that challenges this scenario. Gaiasia is represented by several large, semi-articulated skeletons characterized by a weakly ossified skull with a loosely articulated palate dominated by a broad diamond-shaped parasphenoid, a posteriorly projecting occiput, and enlarged, interlocking dentary and coronoid fangs. Phylogenetic analysis resolves Gaiasia within the tetrapod stem group as the sister taxon of the Carboniferous Colosteidae from Euramerica. Gaiasia is larger than all previously described digited stem tetrapods and provides evidence that continental tetrapods were well established in the cold-temperate latitudes of Gondwana during the final phases of the Carboniferous–Permian deglaciation. This points to a more global distribution of continental tetrapods during the Carboniferous–Permian transition and indicates that previous hypotheses of global tetrapod faunal turnover and dispersal at this time must be reconsidered.

 

Claudia A. Marsicano, Jason D. Pardo, Roger M. H. Smith, Adriana C. Mancuso, Leandro C. Gaetano  and Helke Mocke. 2024. Giant stem Tetrapod was Apex Predator in Gondwanan late Palaeozoic ice age. Nature.  DOI: 10.1038/s41586-024-07572-0

[Paleontology • 2023] Krommaster spinosus • Earliest Known ophiuroids (Ophiuroidea: Encrinasteridae) from high Palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa

Krommaster spinosus

Reddy, Thuy, Reid & Gess, 2023

 

DOI: 10.1371/journal.pone.0292636

Abstract

For the first time, ophiuroids have been found in South African strata predating the lowermost Bokkeveld Group. These comprise natural moulds and casts from two localities in the ‘upper unit’ of the Baviaanskloof Formation (Table Mountain Group). As a Pragian to earliest Emsian age has been inferred for this member, the new taxa comprise the earliest high-palaeolatitude ophiuroid records from southern Gondwana. Morphological analysis of the specimens revealed the presence of two distinct taxa. One is here described as Krommaster spinosus gen. et sp. nov., a new encrinasterid characterised by very large spines on the dorsal side of the disc, the ventral interradial marginal plates and the arm midlines. The second taxon is a poorly preserved specimen of Hexuraster weitzi, a cheiropterasterid previously described from the slightly younger Bokkeveld Group.

 

   

Krommaster from the Baviaanskloof Formation, Upper Unit, Cape Supergroup, Table Mountain Group, Eastern Cape South Africa paratypes.
 A- part aboral view (AM18224) with disk scales preserved, B- counterpart with holes, which comprise moulds of spines (image reversed) (AM18224A), C- silicone peel of the oral view (AM18221). Abbreviations; PS: periradial suture.

Systematic palaeontology

Class– OPHIUROIDEA Gray, 1840  

Order– OEGOPHIUROIDEA Matsumoto, 1915 

Suborder– LYSOPHIURINA Gregory, 1897  

Family– ENCRINASTERIDAE Schuchert, 1914  

Subfamily– ENCRINASTERINAE Schuchert, 1914  

Krommaster gen. nov.

Diagnosis—Moderately large encrinasterid with disk covered by a mosaic of small, thin scales and extending to the 5th or 6th arm segment; interradii bound by relatively small marginal plates except for a single larger plate bearing a single very large, conical, pointed spine; similar but slightly smaller spines on dorsal disk and along the dorsal midline of the arms; ambulacrals with a very sharp transverse furrow close to the distal edge of the leg of the boot; adambulacral plates with two to three relatively large, short, conical, pointed lateral arm spines.

Etmology—‘Kromm’ From Kromme River, in the canyon of which the ophiuroid lag deposit was recovered. Krom is the Afrikaans word for curve. ‘Aster’, latin meaning star.

Krommaster spinosus sp. nov.

 Etymology—‘spinosus’, latin for spiny or spiky, referring to the presence of large spines on the central disk and arms.

Type locality and stratum—Early Devonian, Pragian to earliest Emsian, ‘upper unit,’ Baviaanskloof Formation, Table Mountain Group, Cape Supergroup, Eastern Cape, South Africa.

  Caitlin Reddy, Ben Thuy, Mhairi Reid and Robert Gess. 2023. Earliest known ophiuroids from high palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa. PLoS ONE. 18(10): e0292636. DOI: 10.1371/journal.pone.0292636

 phys.org/news/2023-11-oldest-samples-brittle-stars-supercontinent.html

[PaleoIchthyology • 2024] Afrocascudo saharaensis • A Saharan Fossil and the Dawn of Neotropical Armoured Catfishes in Gondwana

Afrocascudo saharaensis

Brito, Dutheil, Gueriau, Keith, Carnevale, Britto, Meunier, Khalloufi, King, de Amorim & Costa, 2024

 DOI: 10.1016/j.gr.2024.04.008

  

Highlights: 

• We describe a Cretaceous endemic Neotropical freshwater catfish from Morocco.

• Overlooked evolutionary events took place at the outset of the break-up of Gondwana.

• Iconic Neotropical freshwater lineages diversified after surviving the K/Pg extinction.

Abstract

Siluriformes are considered as primarily freshwater and have frequently been a model for the study of historical biogeography. Among catfishes, the most diverse clade is the Loricarioidei, a Neotropical group for which the fossil record extends back to the Palaeocene of Argentina. Here we describe a fossil from the early Late Cretaceous of Morocco, exhibiting typical morphological traits of the Loricariidae. A phylogenetic analysis integrating morphological characters with a multigene database for the main loricarioid lineages and outgroups highly supports inclusion of the fossil within the Loricariidae. A time-calibrated analysis corroborates the origin of loricarioids at about 112 MYA. The presence of this loricariid in Africa provides evidence that loricarioids have diversified before the separation of Africa and South America. The Moroccan loricariid shows an ancient evolutionary history that, in Africa, ended in the Late Cretaceous but persisted in South America, later surviving the K/Pg extinction.

 

Afrocascudo saharaensis gen. et sp. nov.

 

Paulo M. Brito, Didier B. Dutheil, Pierre Gueriau, Philippe Keith, Giorgio Carnevale, Marcelo Britto, François J. Meunier, Bouziane Khalloufi, Andrew King, Pedro F. de Amorim and Wilson J.E.M. Costa. 2024. A Saharan Fossil and the Dawn of Neotropical Armoured Catfishes in Gondwana. Gondwana Research. In Press. DOI: 10.1016/j.gr.2024.04.008

 twitter.com/justin_an74/status/1783944379209855058

[Paleontology • 2024] Chakisaurus nekul • A New ornithopod from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina: Implications on elasmarian postcranial Anatomy

 

Chakisaurus nekul 

 Nogueira, Rozadilla, Agnolín, Marsà, Motta & Novas, 2024

 

 DOI: 10.1016/j.cretres.2024.105874

 

Abstract

The aim of the present contribution is to describe the first ornithischian species from the Huincul Formation (Cenomanian-Turonian, Upper Cretaceous) at the Pueblo Blanco Natural Reserve, Río Negro province, Argentina. The new species, named Chakisaurus nekul gen. et sp. nov., can be comfortably included among elasmarian ornithopods. The new species shows humeral anatomy that is congruent with smaller members of the clade (e.g. Anabisetia, Notohypsilophodon), and differs from larger taxa (e.g. Talenkauen, Mahuidacursor) which show humeral features probably related with graviportal habits, such as lack of shaft torsion and a distally located deltopectoral crest. This indicates that graviportal habits were probably acquired independently in elasmarians from other large-sized taxa, such as hadrosauroids. Caudal vertebrae of the new species also show a unique combination of characters shared with other elasmarians, which are absent in previously known ornithopods. These features indicate that some elasmarians had a protonic tail posture, which is unknown in other ornithischians and was previously considered unique to derived titanosaurian sauropods. The shape of transverse processes and neural spines of caudal vertebrae indicate that at least some elasmarians had improved cursorial habilities, that were convergently acquired by selected theropod clades.

Systematic paleontology

DINOSAURIA Owen, 1842

ORNITHISCHIA Seeley, 1887

ORNITHOPODA Marsh, 1881

ELASMARIA Calvo, Porfiri & Novas, 2007

Chakisaurus nekul gen. et sp. nov.

Conclusions: 

The new genus and species Chakisaurus nekul is described here based on several juvenile and adult specimens. It constitutes the first named ornithischian from the Huincul Formation and sheds light on tail and humeral anatomy in elasmarians. Caudal anatomy of elasmarians, and ornithopods in general, is poorly known, and thus, Chakisaurus constitutes an important addition to the knowledge of this region of the ornithopod body. Furthermore, its humeral shape is very different from other ...

Rodrigo Alvarez Nogueira, Sebastián Rozadilla, Federico L. Agnolín, Jordi A. Garcia Marsà, Matias J. Motta and Fernando E. Novas. 2024. A New ornithopod from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina: Implications on elasmarian postcranial Anatomy. Cretaceous Research. 159; 105874. DOI: 10.1016/j.cretres.2024.105874

[Paleontology • 2024] Vasuki indicus • Largest known madtsoiid Snake (Ophidia: Madtsoiidae) from warm Eocene period of India suggests intercontinental Gondwana dispersal

Vasuki indicus

Datta & Bajpai, 2024

DOI: 10.1038/s41598-024-58377-0

Nix Illustration (CC BY-NC 4.0) (modified Madtsoiidae illustration)

Abstract

Here we report the discovery of fossils representing partial vertebral column of a giant madtsoiid snake from an early Middle Eocene (Lutetian, ~ 47 Ma) lignite-bearing succession in Kutch, western India. The estimated body length of ~ 11–15 m makes this new taxon (Vasuki indicus gen et sp. nov.) the largest known madtsoiid snake, which thrived during a warm geological interval with average temperatures estimated at ~ 28 °C. Phylogenetically, Vasuki forms a distinct clade with the Indian Late Cretaceous taxon Madtsoia pisdurensis and the North African Late Eocene Gigantophis garstini. Biogeographic considerations, seen in conjunction with its inter-relationship with other Indian and North African madtsoiids, suggest that Vasuki represents a relic lineage that originated in India. Subsequent India-Asia collision at ~ 50 Ma led to intercontinental dispersal of this lineage from the subcontinent into North Africa through southern Eurasia.

 

Systematic paleontology

Squamata Oppel, 1811

Ophidia Brongniart, 1800

Madtsoiidae (Hoffstetter 1961) McDowell, 1987

Vasuki indicus gen. et sp. nov.

Etymology: Generic name after the well-known Hindu mythical serpent ‘Vāsuki’ around the neck of Lord Shiva; specific name is for the country of origin i.e., India.

Holotype: IITR/VPL/SB 3102-1-21; a partial vertebral column representing the precloacal region

Horizon and locality: Naredi Formation; Panandhro Lignite Mine, district Kutch, Gujarat state, western India.

Diagnosis: Vasuki exhibits a unique combination of the following characters: presence of prominent paracotylar foramina (shared with Madtsoiidae); middle-sized cotyle (shared with Madtsoiidae); median prominence on ventral margin of centrum (shared with Madtsoiidae); prezygapophyseal process absent; high angle of synapophysis with horizontal in anterior view (avg. 71.5°); MTV diapophysis level with dorsoventral midpoint of neural canal (shared with Madtsoia madagascariensis, Madtsoia camposi, Wonambi barriei and Adinophis); prezygapophyseal buttress succeeded posteriorly by elliptical fossa (shared with Madtsoia pisdurensis); deep V-shaped embayment (shared with Gigantophis garstini and Madtsoia pisdurensis); oval precloacal cotyle (shared with Gigantophis garstini and Madtsoia pisdurensis); transversely wide vertebrae (shared with Gigantophis garstini and Madtsoia pisdurensis); neural spine posteriorly canted (shared with Gigantophis garstini and Madtsoia pisdurensis); broad hemal keel with posterior process (shared with Gigantophis garstini and Madtsoia pisdurensis); strongly notched anterior zygosphenal margin; endozygantral foramen present (shared with Madtsoia madagascariensis, Powellophis and Gigantophis garstini).

Autapomorphies: exceptionally large vertebrae [centrum length (cL): 37.5–62.7 mm and prezygapophyseal width (prW): 62.4–111.4 mm]; neural spine cross-section spade-shaped; poorly developed hemal keel which remains dorsal to the parapophyses; chisel-shaped posterior process of the hemal keel.

 

Debajit Datta and Sunil Bajpai. 2024. Largest known madtsoiid Snake from warm Eocene period of India suggests intercontinental Gondwana dispersal. Scientific Reports. 14, 8054. DOI: 10.1038/s41598-024-58377-0

 www.scientificamerican.com/article/this-nearly-50-foot-snake-was-one-of-the-largest-to-slither-the-earth 

[Paleontology • 2024] Thyreosaurus atlasicus • A New stegosaurian dinosaur (Ornithischia: Thyreophora) with A remarkable dermal armour from the Middle Jurassic of North Africa

Thyreosaurus atlasicus

Zafaty, Oukassou, Riguetti, Company, Bendrioua, Tabuce, Charrière & Pereda-Suberbiola, 2024

DOI: 10.1016/j.gr.2024.03.009

 

Highlights: 

• Thyreosaurus atlasicus, a new stegosaur from the Middle Jurassic of North Africa is presented.

• The new taxon is characterised by an asymetric bizarre dermal armour, unique among stegosaurs.

• Thyreosaurus is closely related to Dacentrurus among Dacentrurinae.

• The discovery is important in understanding the evolutionary history of thyreophorans.

Abstract

In recent years the Middle Atlas of Morocco has become an area of interest for the study of dinosaurs in northern Africa. The Boulahfa locality, near Boulemane, has produced a diverse dinosaur assemblage from the Middle Jurassic of the El Mers Group. Fossil remains of sauropods and thyreophorans, such as ankylosaurs (Spicomellus) and stegosaurs (Adratiklit), have been reported thus far in this region. Here, we describe a new partial thyreophoran skeleton found in the gray marls of the El Mers III Formation (Bathonian-? Callovian), which mainly consists of disarticulated dorsal vertebrae and ribs, and associated dermal armour elements. Axial characters (e.g., elongated pedicels of the dorsal neural arches; upturned transverse processes and dorsal ribs with straight axes suggesting a narrow ribcage) indicate that the specimen belongs to a medium to large-sized stegosaur. The dorsal vertebrae show differences with those of Adratiklit, whose material has been found at the same stratigraphic levels. Thyreosaurus atlasicus gen. et sp. nov. is characterized by a remarkable dermal armour, which consists of thick (up to 4 cm) subovate to subrectangular-shaped osteoderms. The asymmetrical texture of their sides, one roughly ornamented with small pits and fiber bundles, the other with a well-marked cross-hatched pattern, is clearly different from that observed to date in other stegosaurs (and ankylosaurs). The bone histology of these osteoderms is reminiscent of that of stegosaur tail spines. It is interpreted that these osteoderms were arranged in a recumbent position over the body of the animal, instead of an erect position. The holotype corresponds to an adult individual who did not reach its maximum body size (estimated body length 6 m). The phylogenetic analysis suggests that Thyreosaurus is closely related to Dacentrurus within Dacentrurinae. The recent discoveries of Adratiklit and Thyreosaurus provide insight into the early evolution of stegosaurs in the Middle Jurassic of Africa.

Thyreosaurus atlasicus gen. et sp. nov.

Omar Zafaty, Mostafa Oukassou, Facundo Riguetti, Julio Company, Saad Bendrioua, Rodolphe Tabuce, André Charrière and Xabier Pereda-Suberbiola. 2024. A New stegosaurian dinosaur (Ornithischia: Thyreophora) with A remarkable dermal armour from the Middle Jurassic of North Africa. Gondwana Research. In Press. DOI: 10.1016/j.gr.2024.03.009

[Paleontology • 2024] Minqaria bata • A New small Duckbilled Dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and Dinosaur Diversity in the late Maastrichtian of North Africa

  

 Minqaria bata 

Longrich, Pereda-Suberbiola, Bardet & Jalil, 2024

 DOI: 10.1038/s41598-024-53447-9 

 twitter.com/NickLongrich

 Researchgate.net/publication/378181686

Reconstruction by Raul Martin 

Abstract

In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians and abelisaurids dominated the Gondwanan continents; hadrosaurids, ceratopsians and tyrannosaurs dominated North America and Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus, was reported from the late Maastrichtian phosphates of the Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia and Gondwana. Here we report new fossils from the phosphates of Morocco showing lambeosaurines achieved high diversity in the late Maastrichtian of North Africa. A skull represents a new dwarf lambeosaurine, Minqaria bata. Minqaria resembles Ajnabia odysseus in size, but differs in the ventrally positioned jugal facet and sinusoidal toothrow. The animal is small, ~ 3.5 m long, but the fused braincase shows it was mature. A humerus and a femur belong to larger hadrosaurids, ~ 6 m long, implying at least three species coexisted. The diversity of hadrosaurids in Europe and Africa suggests a dispersal-driven radiation, with lambeosaurines diversifying to take advantage of low ornithischian diversity. African lambeosaurines are small compared to North American and Asia hadrosaurids however, perhaps due to competition with titanosaurians. Hadrosaurids are unknown from eastern Africa, suggesting Moroccan hadrosaurids may be part of a distinct insular fauna, and represent an island radiation.

Skull elements of Minqaria bata nov. gen. et sp., MHNM.KHG.1395, holotype: right maxilla, braincase, left dentary. Sidi Chennane, Oulad Abdoun Basin, Upper Couche III, late Maastrichtian. Scale = 5 cm.

Systematic paleontology

Dinosauria Owen, 1842

Ornithischia Seeley, 1887

Iguanodontia, Baur, 1891

Hadrosauridae Cope, 1869

Lambeosaurinae Parks, 1923

Arenysaurini Longrich, Pereda-Suberbiola, Pyron et Jalil, 2021

Minqaria bata gen. et sp. nov.

Diagnosis. Small lambeosaurine characterized by the following character combination, which also differentiates it (where the specimens overlap) from Ajnabia odysseus. Jugal articulation lies very low on maxilla (autapomorphic within lambeosaurinae); ectopterygoid ridge ends at jugal articulation. Ectopterygoid ridge concave in lateral and dorsal views, narrower posteriorly than anteriorly. Neurovascular foramina arranged in a row. Highly domed frontoparietal, with extensive contribution of parietal to the dome, and a triangular parietal table. Maxillary toothrow sinusoidal in lateral or ventral views, with a deep buccal fossa. Dentary short and deep, occlusal margin straight; symphyseal process strongly extended anteriorly, and with straight ventral margin. Alveolar ridges of maxilla and dentary poorly developed. Teeth small, with narrow apices, broad central ridges, and rugose enamel.

Locality and horizon. Sidi Chennane, Oulad Abdoun Basin, Morocco; upper Couche III, late Maastrichtian. 

Etymology. Arabic, ‘minqar’, beak; ‘bata’, duck.

Conclusions: 

A hadrosaurid from the latest Maastrichtian phosphates of Sidi Chennane, Morocco, is distinct from Ajnabia odysseus and represents a new arenysaurin, Minqaria bata. Minqaria differs from Ajnabia in jaw and tooth morphology, suggesting it occupied a distinct niche. Fusion of cranial elements shows that it was mature despite its small size (~ 3.5 m), confirming the existence of small hadrosaurids in North Africa. Similarities with the European Arenysaurus provide further evidence for dispersal of lambeosaurines between the Ibero-Armorican landmass and Africa. A humerus from Sidi Daoui and a femur from Mrah Lahrach belong to larger individuals, suggesting at least three hadrosaur species occur in the phosphates. Even as lambeosaurines declined in the Maastrichtian of North America, they diversified in Africa.

Nicholas R. Longrich, Xabier Pereda-Suberbiola, Nathalie Bardet and Nour-Eddine Jalil. 2024. A New small Duckbilled Dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and Dinosaur Diversity in the late Maastrichtian of North Africa. Scientific Reports. 14: 3665. DOI: 10.1038/s41598-024-53447-9

  twitter.com/NickLongrich/status/1759633471071310199 

 Researchgate.net/publication/378181686_A_new_small_duckbilled_dinosaur_from_Morocco

Little African duckbill dinosaurs provide evidence of an unlikely ocean crossing

New species of duckbill dinosaur found in Africa indicates they were diverse, with at least three species inhabiting north Africa at the end of the Cretaceous.

 www.BATH.ac.uk/announcements/little-african-duckbill-dinosaurs-provide-evidence-of-an-unlikely-ocean-crossing/

 

[Paleontology • 2024] Kwatisuchus rosai • Interrelationships Among early Triassic Faunas of Western Gondwana and Laurasia as illuminated by A New South American benthosuchid temnospondyl (Temnospondyli: Stereospondyli: Benthosuchidae)

 Kwatisuchus rosai

 Pinheiro, Eltink, Paes-Neto, Machado, Simões & Pierce, 2024

DOI: 10.1002/ar.25384 

 twitter.com/FeliPinheir 

 UniPampa.edu.br

artwork: Márcio L. Castro

Abstract

The End-Permian Mass Extinction marked a critical turning point in Earth's history, and the biological recovery that followed the crisis led to the emergence of several modern vertebrate and invertebrate taxa. Even considering the importance of the Early Triassic biotic recovery for the evolution of modern faunas and floras, our knowledge of this event is still hindered by the sparse sampling of crucial geological formations. This leaves our understanding of Early Triassic ecosystems fundamentally biased toward productive and historically well-explored geological units. Recent surveys in poorly known Gondwanan localities, such as those within the Sanga do Cabral Formation in southern Brazil, have unveiled insights into Early Triassic terrestrial ecosystems, shedding light on a diverse and previously unknown tetrapod fauna. Here, we report the discovery of a new temnospondyl genus and species in the Lower Triassic Sanga do Cabral Formation. The new taxon can be confidently assigned to the Benthosuchidae, a stereospondyl clade with a distribution previously restricted to the East European Platform. Phylogenetic analysis confirms the relationship of the new genus to the trematosaurian lineage, being closely related to the genus Benthosuchus. Our results raise questions about the biogeographical history of stereospondyls after the End-Permian Mass Extinction and suggest a potential connection between Russian and South American Early Triassic faunas. Further investigations are needed to thoroughly explore the potential dispersal routes that may explain this seemingly unusual biogeographical pattern.

Keywords: biogeography, Lower Triassic, Sanga do Cabral Formation, Stereospondyli

 Kwatisuchus rosai

Felipe L. Pinheiro, Estevan Eltink, Voltaire D. Paes-Neto, Arielli F. Machado, Tiago R. Simões and Stephanie E. Pierce. 2024. Interrelationships Among early Triassic Faunas of Western Gondwana and Laurasia as illuminated by A New South American benthosuchid temnospondyl. The Anatomical Record. DOI: 10.1002/ar.25384

  twitter.com/FeliPinheir/status/1748419341261943133

Descoberta: Anfíbio gigante mais antigo que dinossauros é encontrado no Rio Grande do Sul

Novo animal mostra semelhança entre faunas do Brasil e Rússia

 UniPampa.edu.br/saogabriel/descoberta-anfibio-gigante-mais-antigo-que-dinossauros-e-encontrado-no-rio-grande-do-sul