PALEONTOLOGY IN AUGUST, 2024

ABSTRACT

Isolated mosasaur teeth and vertebrae recovered from beds of the Guadalupe Group of central Boyacá, Colombia, are reported. A partial tooth crown identified as Globidens sp., found in the Labor-Tierna Formation (Maastrichtian), represents the first report of this genus from northern South America and its most equatorial occurrence. A tooth crown recovered from the Plaeners Formation (upper Campanian–lower Maastrichtian), represents the youngest record of the subfamily Plioplatecarpinae in Colombia. These occurrences collectively constitute the youngest record of the family Mosasauridae in Colombia and expand both the taxonomic diversity and biogeography of mosasaurids in northern South America.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667124001708

ABSTRACT

Peirosauridae (Crocodyliformes, Notosuchia) is one of the fossil lineages of crocodyliforms ubiquitous in the Cretaceous deposits of the Bauru Basin. Here, we describe a new species of a longirostrine Peirosauridae from the Adamantina Formation (Bauru Basin, Late Cretaceous). The specimen consists of a partially preserved skull with a cranial roof, interorbital region, and fragments of the posterior portion of the rostrum, including the prefrontal and lacrimal; left hemimandible, with 14 alveoli and 12 teeth; and a single cervical rib fragment. The specimen is associated with Peirosauridae by three cranial synapomorphies, and it can be assigned to a new genus and species by presenting seven cranial and one tooth apomorphies. To clarify the position of the new taxon, an updated phylogenetic analysis was performed with increased sampling of taxa of Notosuchia, especially Peirosauridae, and phylogenetically relevant characters. Our results indicated the monophyly of Peirosauridae, formed by two main lineages, the oreinirostral and presumably terrestrial Peirosaurinae and the longirostrine and presumably semi-aquatic Pepesuchinae. The recovering of both lineages as distinct entities was also reinforced through a morphospace analysis. Pepesuchinae were notable by exploring a position of the morphospace not explored by any other Notosuchia. Their longer rostra and the assumption of them being gradually specialized to aquatic habits reflects the unique diversity of these crocodyliforms through the Cretaceous deposits of South America and Africa.

LINK(S)

https://anatomypubs.onlinelibrary.wiley.com/doi/abs/10.1002/ar.25559

ABSTRACT

Background: Gastroliths are stones of uncertain purpose that are commonly found inside the rib cages of plesiosaur fossils worldwide. Gastroliths from four Alberta (Canada) plesiosaurs were studied to determine both their shapes and masses, and their mass fractions relative to body mass. One animal’s set of gastroliths was 100% complete and fully visible, but the others showed varying degrees of loss, damage or obscuration, so estimations of their original states were needed.

Methods: The studied animals were: Albertonectes vanderveldei, Fluvionectes sloanae, Nichollssaura borealis and Wapuskanectes betsynichollsae. The animals come from three different palaeoenvironments: open marine, near shore marine, and fluvial. Gastrolith shapes were classified as either xiphoid, cylindrical, discoidal or spherical based on observed and/or estimated dimensions. Although not all methods could be applied in all cases, gastrolith shapes and masses were estimated four different ways: (1) direct measurement and weighing of a subset and predicting the properties of the remaining obscured and hidden stones; (2) measuring triaxial ellipsoid dimensions of free stones to calculate volumes and multiplying by the mass density of chert; (3) measuring two visible triaxial dimensions of embedded stones, estimating the hidden third dimension three different ways, and then determining volumes and masses by calculation; and (4) predicting the density and mass of a densely packed cluster of small gastroliths using geometrical arguments.

Results: Total gastrolith mass never exceeded 0.2% of body mass in any plesiosaur, and is consistent with the idea that the amounts of gastroliths recovered with plesiosaurs would be ineffective as ballast. The largest plesiosaur in the sample had the largest single gastrolith and total gastrolith mass increases with body size. The shape characteristics of the gastroliths were different for different environments, but compositionally they are dominated by black cherts. A possible common source for the gastroliths was identified for the two geographically close and near-contemporanous Nichollssaura and Wapuskanectes.

LINK(S)

https://peerj.com/articles/17925/

https://peerj.com/articles/17925.pdf

ABSTRACT

A non-hadrosaurid hadrosauroid, Qianjiangsaurus changshengi gen. et sp. nov., is named and described here based on an incomplete, partially articulated skeleton from the top of the Upper Cretaceous Zhengyang Formation in Qianjiang District, Chongqing Municipality, southwest China. The skeleton displays a transitional morphology between non-hadrosaurid hadrosauroids and hadrosaurids. The diagnosis of the taxon is therefore defined as a unique combination of characters, including a series of plesiomorphic features typical of non-hadrosaurid hadrosauroids, some apomorphic features common among hadrosaurids but rarely reported in non-hadrosaurid hadrosauroids, and a probable autopomorphy, namely the fan-shaped prepubic process of the pubis strongly anteroposteriorly constricted and dorsoventrally expanded, with the length/height ratio of ∼0.79. Phylogenetic analysis recovers a sister-taxon relationship between Qianjiangsaurus and Plesiohadros outside of Hadrosauridae, and the clade consisting of the two taxa is positioned higher on the tree than Gobihadros and Gilmoreosaurus, but below the clade of Telmatosaurus + Tethyshadros, Eotrachodon and Zhanghenglong. Combining the morphological data with the phylogenetic topology identifies Q. changshengi as a late-branching non-hadrosaurid hadrosauroid. Given that the age assemblage of the eight hadrosauroids closely related to Qianjiangsaurus in phylogeny spans the Santonian–early Maastrichtian time interval, the top of the Zhengyang Formation, from which Qianjiangsaurus is recovered, is possibly restricted to the late Late Cretaceous in age. Hierarchical clustering of twelve hadrosauroid-bearing dinosaur assemblages from the Late Cretaceous deposits of Asia shows a strong correlation between the Zhengyang Formation and the Djadokhta and Baruungoyot formations in Mongolia that supports coeval interchange of dinosaur faunas across East Asia.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S019566712400168X

ABSTRACT

Fossil snakes of the family Palaeophiidae are primarily known from rare, isolated vertebrae, leading to a poor understanding of the intra- and inter-columnar variation within a palaeophiid species. This leads to ambiguity in the taxonomic identity of these snakes, as in the case of the Eocene-age marine snakes of the genus Pterosphenus, in which the majority of species have been described by characters of problematic taxonomic value. Here, we propose a taxonomic revision of the genus based on an articulated to semi-articulated section of the vertebral column at the anterior to mid trunk-transition of Pterosphenus schucherti discovered from the middle Eocene (Bartonian) Harudi Formation, Kachchh (Kutch) Basin. The characters that separate Pterosphenus schucherti from ‘Pterosphenus schweinfurthi’ and ‘Pterosphenus biswasi,’ viz., the height of the pterapophysis and the anterior concavity of the zygosphene, have been found to be non-diagnostic, and the latter two species have been synonymized with the type species. Additionally, we utilized 2D and 3D landmark-based geometric morphometry to determine the morphometric affinity of palaeophiids amongst the alethinophidian snakes. The body size of the snake was estimated based on extant snakes with a morphometric affinity to Palaeophiidae. The cosmopolitan distribution of Pterosphenus schucherti is modelled based on the sea surface temperature (SST) constraints of the modern cosmopolitan snake Hydrophis platurus, and the known fossil localities of the species. The present findings provide crucial insights into the global paleoecological landscape of the Eocene, and the interactions of Pterosphenus schucherti with other palaeophiid snakes as well as the other Eocene fauna.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2375332

ABSTRACT

During April 2022, offshore dredging for a storm damage beach renourishment project placed large quantities of Upper Cretaceous (upper Maastrichtian) Peedee Formation sediment onto the shores of Holden Beach in Brunswick County, North Carolina, USA. The Cretaceous sediment is highly fossiliferous and has yielded a rich and diversified assemblage of fossils from mosasaurid reptiles. New fossil material, namely isolated teeth, consists of several dental morphologies from the mosasaur subfamilies Halisaurinae and Mosasaurinae. Five species are recognized: Halisaurus sp., Mosasaurus cf. beaugei Arambourg, 1952, Mosasaurus cf. hoffmannii Mantell, 1829, Prognathodon cf. solvayi Dollo, 1889 and Prognathodontini indet. In this assemblage, prognathodontins predominate, being the most abundant marine reptile find, with all other species being comparatively rare. The mosasaur assemblage of North Carolina shows close affinity with the phosphates of Morocco, containing species typical of both the northern and southern margins of the Mediterranean Tethys. These new discoveries improve our knowledge of the biodiversity of mosasaur fauna from the late Maastrichtian of North Carolina and add to the known paleobiogeographical distribution of these taxa. The material described within was collected courtesy of the efforts of amateur fossil hunters and seasonal tourists combing Holden Beach for fossilized remains.

LINK(S)

https://www.zin.ru/journals/trudyzin/eng/publication.html?id=566

https://www.zin.ru/journals/trudyzin/doc/vol_328_3/TZ_328_3_Rempert.pdf

ABSTRACT

The early Silurian Chongqing Lagerstätte (middle Telychian) yields exceptionally preserved articulated jawless and jawed fishes. Here, we describe a new eugaleaspiform (Galeaspida, jawless stem-Gnathostomata), Miaojiaaspis dichotomus gen. et sp. nov., from the Chongqing Lagerstätte in Xiushan, Chongqing, China. The new form resembles Tujiaaspis vividus in the short medial dorsal canal, and the presence of the branching ends of the lateral transverse canal. They differ in that T. vividus has highly developed subordinate branches of the sensory canals that form a reticulate sensory canal system, and the median dorsal opening is more elongated. Our phylogenetic analysis recovers M. dichotomus and T. vividus as a monophyletic clade (Tujiaaspidae fam. nov.), which is supported by two synapomorphies: the short medial dorsal canal, and the branching ends of the lateral transverse canal. Tujiaaspidae forms a trichotomy with Shuyuidae and a clade comprising Anjiaspis, Sinogaleaspidae, Yongdongaspidae, and the ‘eugaleaspid cluster’. The sensory canal patterns in galeaspids are compared to show the transformation sequence of the sensory canal system in Eugaleaspiformes.

LINK(S)

https://www.vertpala.ac.cn/EN/10.19615/j.cnki.2096-9899.240820

ABSTRACT

Recent fieldwork in the late Middle Jurassic Balabansai Formation of Kyrgyzstan has yielded a partial skeleton of a large theropod dinosaur. The material includes a few bones of the skull (postorbital, quadratojugal), dorsal and sacral vertebrae, fragments of the pectoral girdle and forelimbs, and an almost complete pelvic girdle and hindlimbs, and is here made the type of a new theropod taxon, Alpkarakush kyrgyzicus gen. et sp. nov. Alpkarakush can be diagnosed by an extremely developed orbital brow on the postorbital, a pneumatic opening leading into cavities in the neural arch from the centroprezygodiapophyseal fossa in the posterior dorsal vertebrae, an almost enclosed ventral sulcus in manual phalanx II-1, a narrow and deep intercondylar groove on the anterior side of the distal femur, and an epicondylar crest on the distal femur that is offset from the distal end. A second, fragmentary, and smaller specimen from the same site represents the same taxon. Based on long bone histology, the type of Alpkarakush represents a late subadult individual, whereas the smaller specimen is a juvenile, possibly indicating gregarious behaviour. Phylogenetic analysis places Alpkarakush in the Metriacanthosauridae, underlining the diversity and wide distribution of this clade in the Jurassic of Asia.

LINK(S)

https://academic.oup.com/zoolinnean/article/201/4/zlae090/7736730

ABSTRACT

“Pegasus” volans is a highly unusual fossil teleost fish from the celebrated Eocene Bolca Lagerstatte. The fossil, known on the basis of two specimens, has been historically assigned to seamoths (Pegasidae), then to oarfish and relatives (Lampriformes). We describe its enigmatic skeletal anatomy in detail, and provide a new genus name. “Pegasus” volans is an extremely elongate and slender animal, with long anal and dorsal fins and a very well-developed first dorsal-fin ray reminiscent to the vexillum of some modern teleost larvae. Most striking is its extreme ventral projection of the pelvic girdle (basipterygium), associated with an element of the pectoral girdle (a long process of the coracoid) and developed pelvic-fin rays. The strongly reduced abdominal region suggests that “Pegasus” volans had an external gut, once again reminiscent of those of certain larval teleosts. The unique character state combination displayed by “Pegasus” volans make it impossible to assign it to a specific subclade within perch-like spiny-rayed fishes (Percomorpha). Nevertheless, it offers a valuable perspective on the diversity of morphologies and ecological niches occupied by teleost fishes of the early Eocene Bolca fauna.

LINK(S)

https://www.biorxiv.org/content/10.1101/2024.08.19.608581v1

https://www.biorxiv.org/content/biorxiv/early/2024/08/19/2024.08.19.608581.full.pdf

ABSTRACT

The vertebrate assemblage of the Lower Jurassic Kayenta Formation is known for its preservation of post-end Triassic mass extinction lineages, including lissamphibians, lepidosaurs, turtles, mammaliamorphs, crocodylomorphs, pterosaurs, and ornithischian, theropod, and sauropodomorph dinosaurs. Most of the body fossils from the formation are known from its ‘silty facies’ in north-central Arizona and southwestern Utah, whereas the sandier ‘typical facies’ of northeastern Arizona preserves few body fossils, and until recently they were completely absent in the typical facies of southeastern Utah. A 2011 team conducting a paleontological survey of Arches National Park discovered the first body fossils from the typical facies of the Kayenta Formation in Utah, here identified as belonging to a single individual of a saurischian dinosaur, likely a theropod. The fossil elements include a partial centrum articular face, a prezygapophysis, part of a caudal vertebra, the distal end of a left radius, part of the distal end of a left femur, a shaft fragment from the left fibula, the distal end of right metatarsal I, and the proximal portion of left metatarsals III and IV. This specimen from Arches National Park underscores the importance of federally protected land in fossil resource management and suggests that the typical facies of the Kayenta Formation may be undersampled and could preserve more vertebrate bones than previously thought.

LINK(S)

https://giw.utahgeology.org/giw/index.php/GIW/article/view/149

ABSTRACT

An articulated group of skeletal elements comprising a sacrum, both ilia and a first caudal vertebra, plus an isolated tooth found in immediate proximity to the bones, from the lower Cenomanian Chalk at Saint-Jouin-Bruneval (Seine-Maritime, Normandy, France) is described and attributed to a new genus and species of abelisaurid theropod, Caletodraco cottardi, on the basis of several characters of the sacrum and pelvis. The peculiar shape of the transverse process of the first caudal vertebra shows that Caletodraco cottardi differs from majungasaurine abelisaurids previously described from Europe, such as Arcovenator escotae, and belongs to the Furileusauria, a group of derived abelisaurids hitherto recognized only from South America. The presence of a furileusaurian abelisaurid in the Cenomanian of Normandy suggests that the biogeographical history of the Abelisauridae in Europe was more complex than hitherto admitted. Several previously described European abelisaurids, such as the Albian Genusaurus sisteronis, may in fact belong to the Furileusauria.

LINK(S)

https://www.mdpi.com/2813-6284/2/3/9%20?utm_campaign=journnews_ccbj_ijerph&utm_medium=social_journ&utm_source=facebook

ABSTRACT

Multiple cranial and mandibular remains of Hyperodapedon huxleyi known from the lower part of the Upper Triassic Maleri Formation were examined to reveal distinct bite marks. These were identified as punctures based on their circular or oval or elliptical outline and deep penetration into the cortical bone, and were found associated with several bone-damaging features such as radiating fractures, serrated boundaries, and collapsed bony surface. In addition, bite traces or drag marks in the form of parallel grooves with U-shaped cross sections are identified. The bite marks are compared with dental morphology of varied Late Triassic carnivores of India, and the probable producers are suggested to be phytosaurs and dinosauriforms. The Maleri trophic structure or food web is reconstructed to reveal interconnectedness between different animal groups, unconfined feeding habits of the animals where the predators were inclined towards opportunistic feeding rather than a niche-based dietary habit. The study highlights the significance of bite marks in the reconstruction of ancient paleoecosystems.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2383735

ABSTRACT

Extant Ganges and Indus river dolphins are endangered species, but their relatives were more diverse in the past. The family Squalodelphinidae is a group of Miocene relatives of Ganges and Indus river dolphins. Our knowledge of squalodelphinids increased slowly in the nineteenth century and has expanded dramatically since the 2010s. Italy, Switzerland, eastern USA, Argentina, and Peru are fossil localities of named and well-preserved squalodelphinid fossils. Squalodelphinids are also known from New Zealand, Germany and Venezuela. However, only two specimens of this family have been reported from the North Pacific, in Washington State, USA, and Japan. Here, a new fossil dolphin (including the skull, right and left periotics and bullae, malleus, incus, hyoid bones and ribs) from the Haze Formation, Ichishi Group, Early Miocene (18.7–18.5 Ma) of Mie Prefecture, Japan is named as the new genus and species Miodelphinus miensis. Phylogenetic analysis places Miodelphinus miensis among squalodelphinids. The periotic of Miodelphinus miensis shows a large, posteriorly widened, ventrally opening, funnel-like articular depression between the posterior and articular processes of the periotic. Miodelphinus miensis contributes to expanding our knowledge of squalodelphinid diversity. Squalodelphinids were distributed widely not only in the Atlantic but also the South and North Pacific by the Early Miocene. This suggests that the family had a chronologically deeper origin such as the beginning of the Early Miocene or older.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/14772019.2024.2378783

ABSTRACT

The early evolutionary and biogeographical history of Gondwanan iguanodontian dinosaurs is poorly understood due to their scarce Lower Cretaceous fossil record. In South America, the Lower Cretaceous iguanodontian osteological record is very fragmentary and most published reports cannot be used to discard or confirm hadrosauroid affinities. The single exception is Tietasaura from Brazil, whose incomplete femur shows a combination of traits found only in non-hadrosauroid iguandontians. Furthermore, no skeletal remains whatsoever of Lower Cretaceous iguanodontians have been reported from the western margin of South America. Here, we describe an isolated ornithopod caudal centrum (SGO.PV.22900) from the Lower Cretaceous Quebrada Monardes Formation in the Atacama Desert, northern Chile. Although incomplete, SGO.PV.22900 presents iguanodontian traits, such as the sub-hexagonal contour of the articular faces, the rectangular profile in lateral view and the absence of transverse processes below the neurocentral suture. We were also able to use quantitative measurements to explore taxonomic affinities, by carrying out a Linear Discriminant Analysis (LDA) and a Principal Components Analysis (PCA) using measurements of caudal centra of several iguanodontian species. The results of both analyses are consistent with those of our comparisons and suggest that SGO.PV.22900 belongs to a non-hadrosauroid iguanodontian ornithopod. This specimen represents one of the most compelling and best documented pieces of osteological evidence of Lower Cretaceous non-hadrosauroid iguanodontian dinosaurs in South America and provides further support for the presence of iguanodontians in the southwestern margin of Gondwana since at least the Early Cretaceous, as previously suggested based on footprints.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667124001563

ABSTRACT

Recently a new genus and species of istiodactylid pterosaur was named by Hone et al. (2020) based on a very complete skeleton from northern China. Although the possibility that the specimen was a chimera was raised by the authors themselves, checks of the specimen revealed no tampering with the specimen and it was considered genuine. The animal was posited as an unusual member of the clade, but characters from both the head and body supported the general identification as an istiodactylid. However, recent damage to the specimen because of flooding in the museum in which it is housed, has revealed that the rostrum and mandible were in fact added to the back of the skull and rest of the body of a second pterosaur. Here we correct the record on this specimen and suggest that Luchibang xingzhe as a taxon is still valid.

LINK(S)

https://palaeo-electronica.org/content/2024/5273-luchibang-is-a-chinese-chimera

https://palaeo-electronica.org/content/pdfs/1359.pdf

ABSTRACT

Dyrosauridae, a clade of neosuchian crocodyliforms, was a significant component of terrestrial and aquatic ecosystems across the latest Cretaceous to Paleogene of North Africa.

Here, we report a dyrosaurid mandibular symphysis recovered from the middle–upper Campanian Quseir Formation near Kharga Oasis in the southern Western Desert of Egypt. This is a partial mandible (MUVP 635), including dentaries and splenials, assigned to Dyrosauridae based on its dental pattern, size, and the shape of the splenial in the symphysis. MUVP 635 exhibits alveolar diameters shorter than the interalveolar distances within the same row. Moreover, the seventh dentary alveolus is significantly large, comparable in size to the fourth dentary alveolus, while the sixth dentary alveolus is positioned close to the seventh dentary alveolus and is as small as the eighth dentary alveolus, which is adjacent to the ninth dentary alveolus. Phylogenetic analysis places MUVP 635 as an early-diverging member of Dyrosauridae, consistent with its middle-late Campanian age. It aligns with a polytomywith Chenanisuchus lateroculi and Anthracosuchus balrogus identified as the most basal members of Dyrosauridae. The discovery of new dyrosaurid material in the Quseir Formation extends the range of Dyrosauridae to the middle Campanian, highlighting the taxonomic richness of the dyrosaurid clade across North Africa and supporting hypotheses of the African origin for this family.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667124001551

ABSTRACT

The Dodo and its extinct sister species, the Solitaire, are iconic exemplars of the destructive capabilities of humanity. These secondarily terrestrial columbids became extinct within a century of their first encounter with humanity. Their rapid extinction, with little material retained in natural history collections, led 18th and some early 19th century naturalists to believe that these aberrant birds were mythological. This meant that the nomenclatural publications in which their scientific nomina were established were based on accounts written before the species became extinct. As such, no type specimens were designated for either the Dodo or the Solitaire. Our in-depth historical overview of both species and associated family-group nomina found that the nominal authority of the Dodo-based family group is not what is reported in the literature. Moreover, our detailed review of the family-group nomina based on columbid genera ensures that the current columbid family-group systematization is valid. Changing nomenclatural norms between the 19th and 20th centuries had a profound impact on Dodo nomenclature; so much so that the Dodo is an example of how pervasive nomenclatural ‘ripples’ can be and a warning for our current world of multiple nomenclatural codes.

LINK(S)

https://academic.oup.com/zoolinnean/article/201/4/zlae086/7733394?login=false

ABSTRACT

Sinosaurus from the Lufeng Basin, Yunnan Province, is the largest and most famous predatory dinosaur from the Early Jurassic in China. Although a number of specimens have been discovered in the past, no studies to date have focused exclusively on complete skeletal articulation, estimation of mass, or life strategies. Based on surface scans of a new well-preserved specimen, a digital skeleton of Sinosaurus was produced in two poses: osteologically neutral pose and extended pose. We estimated the possible living body mass by three volumetric-density methods, advocating the use of the expanding convex hulls method of 849.6 kg with the COM (0.41, 1.31, 0.00) as a more reliable result, which is greater than the mass of traditional regression formulas. The body shape and skull/body length suggested that Sinosaurus was a great runner, and this, combined with the weak crests and large forelimbs, further led to the conclusion that both the head and forelimbs were required to prey. This finding is also consistent with the finding that Sinosaurus has a moderate ability to metabolise body heat in the skin, as reflected by the surface/volume ratio.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2385615

ABSTRACT

Here, we report on the important discovery of two well-preserved maxillae from the durophagous mosasaur Globidens alabamaensis Gilmore, 1912. The maxillae were found in the Ozan Formation embedded in the North Sulphur River channel near Ladonia, Fannin County, Texas, USA. Both maxillae preserve nearly complete tooth rows. In North America, Globidens is amongst the rarest mosasaurs, with remains consisting predominantly of isolated teeth and jaw fragments.

LINK(S)

https://zenodo.org/records/13324299

ABSTRACT

In addition to being an important lacustrine hydrocarbon source rock, the Fengcheng Formation possesses well-preserved sodium‑carbonate evaporite units and tuff beds. Known ancient alkaline salt-lake deposits bearing sodium‑carbonate evaporite minerals like the Late Paleozoic Fengcheng Formation are limited beyond the modern day. However, hitherto the absolute age of the alkaline lacustrine Fengcheng Formation of the Junggar Basin (China) is debated (Late Carboniferous and/or Early Permian), and therefore its temporal link to a specific stage of the Late Paleozoic Ice Age (LPIA) remains unclear. Here, new Resingle bondOs geochronology demonstrates that the Fengcheng Formation is predominately of Late Carboniferous-age (304.4 to 297.3 Ma), and therefore its deposition coincides with the interglacial climate warming interval between glaciation C4 and P1 of the LPIA and not the younger interglacial stages as previously proposed. The Resingle bondOs isotope systematics indicate that the lake water column during the deposition of the Fengcheng Formation had a relatively unradiogenic Os (187Os/188Os, Osi) isotope composition (0.32 to 0.36), which is in contrast to the typical radiogenic Osi recorded for lacustrine deposits throughout geological time. The unradiogenic Osi for the Fengcheng Formation ties the source of the Os in the lake to the weathering of adjacent mafic volcanic rocks and/or hydrothermal input (~0.13). As a result, the penecontemporaneous relationship to the Late Paleozoic interglacial climate warming (causing enhanced evaporation) coupled with weathering of volcanic rocks and/or hydrothermal fluid input into the lake is considered to have been mechanistic in the formation of an alkaline salt lake dominated by sodium and carbonate.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0031018224004309

ABSTRACT

The Early Cretaceous Jehol Biota in northeastern China has yielded a diversity of feathered dromaeosaurid dinosaurs and expanded our knowledge of avian origin and flight evolution. However, histology-based ontogenetic references and detailed morphological studies remain limited relative to the abundant fossils. Here, a new specimen of microraptorine from the Lower Cretaceous Jiufotang Formation is described. This specimen includes a nearly complete postcranial skeleton and inferred as a Microraptor based on revised osteological characters. The femoral length of the new specimen is less than 5 cm, making it the smallest dromaeosaurid individual reported from the Jehol Biota until now. Osteohistological analysis reveals that this individual was a juvenile that is less than one-year old. The new specimen provides additional morphological details that are poorly preserved in the other Microraptor specimens, including aspects of the coracoid, ilium, and tail. Additionally, the sacrals and pubic symphysis of the new specimen have respectively fused at the juvenile stage. This phenomenon suggests caution should be taken in using skeletal fusion for assessing the ontogenetic stage of Microraptor specimens, highlighting the importance of histological analysis.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2385604

ABSTRACT

A new weigeltaspid heterostracan, Orthogoniaspis amnicus nov. sp. represents the first weigeltaspid reported from the Early Devonian Peel Sound and Snowblind Bay formations, Nunavut, Canadian Arctic. One partially articulated specimen shows for the first time that while the main plates of the dorsal shield abutted each other the orbital, pineal and rostral plates were separated by bands of tesserae. The similarity of this arrangement to that of the corvaspids, particularly the presence of dorsal lateral plates and bands of tesserae separating the anterior plates suggests a sister-group relationship, as no other heterostracans share this arrangement. Arctic weigeltaspids range from the late Ludlow to the late Lochkovian (O. amnicus nov. sp.), which is earlier than the related European taxa suggesting an Arctic centre of development for the weigeltaspids, as has been suggested for other heterostracan taxa.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2386679

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.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2383708

ABSTRACT

This study aims to describe a new fossil species of the extant aspredinid genus Bunocephalus. The new species is represented by a nearly complete skull and pectoral girdle coming from late Miocene Ituzaingó Formation beds of Paraná City, Entre Ríos Province, Argentina. The specimen constitutes the first fossil record for the genus and the family Aspredinidae. This finding demonstrates that large temporal and geographical gaps are still present in the fossil record of the South American continent, evidencing the lack of knowledge of the geographical and temporal distribution of many freshwater fish clades.

LINK(S)

https://mapress.com/zt/article/view/zootaxa.5493.4.5

ABSTRACT

The basal macronarian sauropod Europasaurus holgeri is known only from the Late Jurassic of the Langenberg Quarry near Goslar, Lower Saxony, Germany. Europasaurus has been identified as an insular dwarf and shows a clear resemblance to Camarasaurus and Giraffatitan. This study provides a detailed description of the dentition of Europasaurus based on an array of fossils outstanding in their abundance, variety of preservation, and ontogenetic range. Dental morphology for the replacement and functional dentitions, the tooth replacement pattern, and implications for food intake are described for the Europasaurus dentition, which is characterized by broad-crowned teeth. Characteristic features for Europasaurus are the presence of denticles on replacement teeth, the wrinkled enamel, and large wear facets both on the apex and on the carinae of the tooth crowns. The partially articulated skull SNHM-2207-R and isolated tooth rows DfmMh/FV 580.1 and DfmMh/FV 896.7 suggest the presence of strong connective tissue partially covering the teeth. This connective tissue would have provided stability and protection for the teeth. Evidence for this connective tissue include exposed tooth necks, in-situ teeth with strongly resorbed roots which no longer would have been connected to the jaw bone, and wrinkled enamel and its surface pattern. The same features can be observed in other sauropod taxa as well. We therefore suggest that eusauropods in general possessed this connective tissue structure, which may be an autapomorphy of the group. Possibly, this hypothetical structure is homologous to the rhamphotheca in birds and some non-avian theropods, which, however rarely, show such a close integration of keratinous tissue and teeth that we hypothesize here.

LINK(S)

https://peerj.com/articles/17764/

https://peerj.com/articles/17764.pdf

ABSTRACT

Simosauridae is an eosauropterygian clade known by two representatives: Simosaurus gaillardoti, from the Ladinian (Middle Triassic) of France and Germany, and Paludidraco multidentatus, from the Carnian (Upper Triassic) of Spain. However, the fossil record of this clade is relatively abundant, being mostly represented by isolated cranial and postcranial material, which ranges from the uppermost Anisian or the lowermost Ladinian of the Middle East to the Carnian of Europe. Therefore, the clade is considered as exclusive of the western region of the Paleotethys. Information about the postcranial anatomy of the group is mostly restricted to that corresponding to S. gaillardoti, even though the holotype of P. multidentatus preserves a large part of its postcranial skeleton, very well preserved. Thus, a detailed description of this bizarre taxon has not been performed so far. We provide a comprehensive description of the postcranium of the holotype of P. multidentatus, which has been carefully prepared for this study. The detailed comparative study with the postcranial skeleton of S. gaillardoti allows us to improve knowledge about it, as well as about Simosauridae in relation to other sauropterygian clades.

LINK(S)

https://palaeo-electronica.org/content/2024/5299-postcranium-of-paludidraco

https://palaeo-electronica.org/content/pdfs/1405.pdf

ABSTRACT

The late Campanian-Maastrichtian in the Ibero-Armorican domain is rich in titanosaurian fossils. The sauropod remains exhibit a high degree of morphological variability, especially in the commonly-found appendicular elements. The phylogenetic relationships of the Ibero-Armorican titanosaurs are still uncertain but we do know that they experienced a Campanian-Maastrichtian herbivorous faunal turnover. It is probable that the small-to-medium-sized Lirainosaurinae-dominated faunas of the Campanian were replaced by late–early Maastrichtian large-bodied lithostrotian dominated faunas. In this context, the Villalba de La Sierra Formation has yielded an abundant sample of medium-to-large sized titanosaurs. In this study we analyze the morphological variability in the appendicular skeleton of the titanosaurs from the Campanian-Maastrichtian Ibero-Armorican domain. We follow previous attempts to classify the commonly-found isolated titanosaurian femora and expand the proposed methodology. The use of combined phenotypic characters and linear morphometrics can be helpful to analyze the morphological variability and diversity of the Ibero-Armorican titanosaurs. Our findings corroborate the presence of at least two exclusive morphotypes in the Lo Hueco fossil site and one exclusive morphotype in the Poyos site, as well as the presence of previously defined Lirainosaurinae across the Pyrenees during the Campanian-Maastrichtian. The Villalba de La Sierra Formation titanosaurs are also clustered with large-bodied late Maastrichtian titanosaurs. It is possible that either the large-bodied late–early Maastrichtian immigrants, with possible Gondwanan affinities, entered the Iberian Peninsula much earlier or that this group was already present at least during the Campanian-Maastrichtian transition, as the small-sized Lirainosaurinae declined.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667124001423

ABSTRACT

The Mesozoic record of birds in Antarctica is still very patchy, restricted to several specimens of derived ornithurine birds (belonging to Neornithes or stem-Neornithes) that come from Upper Cretaceous outcrops on Vega Island. Because this site was geographically isolated from those containing previously known coeval bird assemblages, comparisons were severely restricted. However, in recent years, paleontological research in the Chorrillo Formation (Maastrichtian) outcropping in southern Santa Cruz province has partially filled this geographical gap. The new prospections have yielded a relatively rich bird assemblage, including fossils attributable to Enantiornithes, Hesperornithiformes, and derived Ornithurae. The present contribution aims to compare the Maastrichtian bird assemblages from Santa Cruz (Patagonia) and Antarctica. One of the main differences between the assemblages is that only Neornithes and kin are present in Antarctica and there are no records of Hesperornithiformes, Enantiornithes or more basal taxa. This may be explained by Neornithes and kin showing accelerated growth and notably high metabolism, which distinguishes them from the slow and cyclic growth of more basal birds and may have allowed them to survive in the relatively cold Antarctic climate.

LINK(S)

https://www.ameghiniana.org.ar/index.php/ameghiniana/libraryFiles/downloadPublic/115

ABSTRACT

Therocephalia are an important clade of non-mammalian therapsids that evolved a diverse array of morphotypes and body sizes throughout their evolutionary history. The postcranial anatomy of therocephalians has largely been overlooked, but remains important towards understanding aspects of their palaeobiology and phylogenetic relationships. Here, we provide the first postcranial description of the large akidnognathid eutherocephalian Moschorhinus kitchingi by examining multiple specimens from fossil collections in South Africa. We also compare the postcranial anatomy with previously described therocephalian postcranial material and provide an updated literature review to ensure a reliable foundation of comparison for future descriptive work. Moschorhinus shares all the postcranial features of eutherocephalians that differentiate them from early-diverging therocephalians, but is differentiated from other eutherocephalian taxa by aspects concerning the scapula, interclavicle, sternum, manus, and femur. The novel anatomical data from this contribution shows that Moschorhinus possessed a stocky bauplan with a particularly robust scapula, humerus, and femur. These attributes, coupled with the short and robust skull bearing enlarged conical canines imply that Moschorhinus was well equipped to grapple with and subdue prey items. Additionally, the combination of these attributes differ from those of similarly sized coeval gorgonopsians, which would have occupied a similar niche in late Permian ecosystems. Moreover, Moschorhinus was the only large carnivore known to have survived the Permo-Triassic mass extinction. Thus, the subtle but important postcranial differences may suggest a type of niche partitioning in the predator guild during the Permo-Triassic mass extinction interval.

LINK(S)

https://peerj.com/articles/17765/

https://peerj.com/articles/17765.pdf

ABSTRACT

The stem lineage of Archosauria is populated by a diverse fossil record that remains notably understudied relative to the crown clade. Prominent among these specimens is a beautifully preserved skull of the early mid-Triassic rhynchosaur Mesosuchus browni [Iziko South African Museum (SAM) 6536], whose phylogenetic position has considerable influence on patterns of pan-archosaurian cranial evolution. We used high-resolution, micro-computed tomography to re-examine the anatomy of this specimen, building on previous studies that were either limited to external observations or restricted to the braincase. A digital segmentation of the cranial elements and primary neurovascular canals of SAM-PK-6536 allows for expanded character scoring and constitutes a foundation for future comparative insights. Our data support the phylogenetically oldest instance of a pneumatized maxilla in a pan-archosaur, bringing the record of antorbital pneumatization into closer alignment with that of the neurocranium. The nasal cavity and primary palate of Mesosuchus includes a complex septomaxilla, a novel element anterior to the vomer, and is likely to have supported a well-developed vomeronasal system. The evolution of this system is discussed in terms of both phylogenetic pattern and how the skeletal architecture of Mesosuchus and other fossils could inform the signalling dynamics that pattern the vomeronasal system during development.

LINK(S)

https://academic.oup.com/zoolinnean/article-abstract/201/4/zlae097/7731279

ABSTRACT

Dinocephalians represent a highly successful early radiation of mid-Permian therapsids. Despite the abundance of their fossils, data on their paleoneurology is challenging to acquire and remain scarce. The current study proposes to overcome these challenges by using digital 3D sculpting. Based on previous works, realistic digital models of brain endocasts and live reconstructions of three taxa sampling the major families of Dinocephalia (Anteosauridae, Titanosuchidae, and Tapinocephalidae) were generated, their volumes measured, and endocranial volume and body mass were estimated. Encephalization quotients were calculated. The results suggest that the dinocephalians evolved a surprisingly high degree of encephalization for such early tetrapods. Some dinocephalians are hypothesized to have practiced head-butting, a complex social behavior, which would have favored the enlargement of the brain. Alternatively, the enlarged endocast may have been filled mostly by protective tissue to protect the central nervous system when the head was used as a weapon. This is supported by the apparent absence of direct imprints of the soft tissue of the brain on the endocast.

LINK(S)

https://palaeo-electronica.org/content/2024/5296-brain-size-in-dinocephalia?fbclid=IwY2xjawEjVu5leHRuA2FlbQIxMAABHbMJK5i5o5IQ9WVen1EnjqRsW-e1mCoOxH4a1vYFxWXLDpdIQ10-sqLwSA_aem_JmfvJyHgsYC1dkZ6baLJyg

https://palaeo-electronica.org/content/pdfs/1377.pdf

ABSTRACT

Sponges are among the most common and diverse Cambrian fossils. However, the origin of the crown groups of the extant sponge classes constitutes the principal problem in the understanding of the evolution of these lower metazoans. New intact spiculate sponges from the lower Cambrian Stage 3–Stage 4 Sinsk Lagerstätte of the Siberian Platform enable a better understanding of the early evolution of crown-group demosponges. The skeletons of Neomenispongia plexa and N. diazoma gen. et sp. nov. consist mostly of simple oxeas, which are organized in relatively regular tufts that are additionally strengthened by sigmoidal spicules. The C-shaped elements of N. diazoma are megascleres in their size range but have sigmoidal shapes similar to sigma microscleres of extant demosponges; the sigmoidal spicules of N. plexa fully accord with microscleres and are the smallest spicules in known Cambrian demosponges. Together with an unnamed early Cambrian demosponge from the Sirius Passet biota (Greenland) and middle Cambrian Ulospongiella from the Burgess Shale (Canada), the new species represent the earliest heteroscleromorph demosponges and indicate an evolutionary origin of microscleres from megascleres. The thin, homogenous skeleton of Keithospongos loricatus gen. et sp. nov. is built of small, spirally arranged oxeas corresponding to the skeletal structure of the primitive Hazeliidae, which have been interpreted as the ancestral skeletal organization of demosponges. These new sponges therefore provide a link from extant spiculate demosponge groups to their more familiar Cambrian ancestors.

LINK(S)

https://onlinelibrary.wiley.com/doi/abs/10.1002/spp2.1582

ABSTRACT

Procolophonidae is the most successful Parareptilia group throughout Pangaea. For almost two decades, the study of the most derived South American procolophonids only included the description of new specimens belonging to well-known species, mostly Procolophon trigoniceps. On the basis of a recently collected skull and associated postcranial elements from the early Carnian (Upper Triassic) of Brazil, we describe a new procolophonid, Cornualbus primus gen. et sp. nov. A phylogenetic analysis recovers this new procolophonid within the subfamily Leptopleuroninae, forming a clade with the leptopleuronines Hypsognathus fenneri, Leptopleuron lacertinum, Mandaphon nadra, Hwiccewyrm trispiculum, and Soturnia caliodon. Cornualbus primus bridges a temporal gap in South American procolophonids, which extended from the Induan to the Norian, in addition to being the oldest Leptopleuroninae described for South America. Furthermore, the description of this taxon enriches our knowledge of procolophonid diversity for the South American Triassic period.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/14772019.2024.2373116

ABSTRACT

Palaeogene South American faunas include enigmatic ungulates that cannot be classified unequivocally within any of the main South American (SA) Native Ungulates clades (Litopterna, Notoungulata, Astrapotheria, Pyrotheria and Xenungulata) because they retain plesiomorphic features, resembling Laurasian ‘archaic ungulates’ traditionally classified within the order ‘Condylarthra’. Most SA ‘condylarths’ are known by partial dental series and isolated teeth and unassociated postcranial remains, hampering comparisons with better-known ungulates. Here, we describe a nearly complete skull and associated mandible of an SA ‘condylarth’, Talquinodus puertai gen. et sp. nov., preserving most of the dentition and basicranium, derived from middle Eocene rocks of the Sarmiento Formation at Central Patagonia. Talquinodus shows a combination of plesiomorphic traits (complete dentition with bunolophodont cheek teeth, ring like ectotympanic, retention of stapedial system, etc.), combined with some autapomorphies, as the reduction of the m3 talonid. Our phylogenetic analyses support consistently that Talquinodus belongs to the SA radiation of Euungulata along with Litopterna, Notoungulata and Astrapotheria. However, the internal relationships could not be resolved unambiguously: Talquinodus could be a didolodontid related to the origin of Litopterna, or could be part of a separate radiation of South American archaic ungulates, along Depaulacoutoia, Lamegoia and Escribania, with no descendants in post-Eocene faunas.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2380810

ABSTRACT

Dinosaur fossils are becoming increasingly well-known from the Bauru Basin of Brazil, and represent some of the last occurring dinosaurs in South America before the end-Cretaceous mass extinction. However, sampling across the basin is not uniform, and comparatively little is known about the fossils from the northern part of the basin. Our fieldwork team discovered two isolated and well-preserved ziphodont theropod teeth from northern basin strata of the Maastrichtian Marília Formation of the south of the state of Goiás. We here identify them using quantitative analysis of morphometric data and comparisons to teeth previously described in the literature. Our comparisons and analyses indicate that they can be assigned to Abelisauridae. These specimens have little evident crown enamel ornamentation, a characteristic widely present in the teeth of theropods from the Southern Hemisphere. The materials described here are the northernmost Bauru Basin abelisaurids reported so far, demonstrating that these carnivorous dinosaurs were important faunal components across the extent of the basin, as they were in other regions of South America.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0895981124002979

ABSTRACT

The dietary changes of early cave bear populations from the Middle to Late Pleistocene are poorly understood. In this study, we analysed 60 m1 through dental microwear analysis of three diachronic Middle (Ursus praekudarensis and U. praekudarensis/kudarensis) to Late Pleistocene (U. kudarensis) populations inhabiting the Kudaro 1 and Kudaro 3 caves in the Southern Caucasus. The diet of all populations was inferred to be omnivorous, although it changed over time, adapting to the climatic and ecological conditions of the period. Bones from U. praekudarensis/kudarensis populations accumulated throughout the year; thus, microwear suggests an average annual diet dominated by plant resources. The widespread presence of hypercoarse scratches in U. kudarensis and U. praekudarensis populations suggests animal protein intake during the hyperphagia. The presence of omnivorous guild competitors and harsh conditions in a high-altitude environment could have driven the Caucasian cave bears to consume animal protein as a fallback diet during their predormancy period. Furthermore, the cave bears' capacity for dietary flexibility through time highlights the ability of cave bears to withstand climatic changes, while competition with other omnivorous species could have driven their dietary niche during their hyperphagia period towards animal protein consumption throughout the Middle to Late Pleistocene.

LINK(S)

https://www.sciencedirect.com/science/article/pii/S0031018224004061

ABSTRACT

The Carboniferous myriapod Arthropleura is the largest arthropod of all time but its fossils are usually incomplete, limiting the understanding of its anatomy, ecology and relationships. MicroCT applied to exceptionally preserved specimens from the Carboniferous Montceau-les26 Mines Lagerstätte (France) reveals unprecedented details of its functional anatomy such as the head and mouthparts. Arthropleura shares features both with millipedes and centipedes. New total-evidence phylogeny combining morphological and transcriptomic data resolves Arthropleura alone as a stem-group millipede, but the inclusion of the highly incomplete Siluro-Devonian Eoarthropleura draws it deeper into the myriapod stem. Arthropleura suggests transitional morphology between clades united primarily by molecular information, and underscores the value of total evidence phylogenetics to understanding evolutionary history.

LINK(S)

https://research.manchester.ac.uk/en/publications/head-anatomy-and-phylogenomics-show-the-carboniferous-giant-arthr

ABSTRACT

The Tuchengzi Formation represents a Jurassic – Cretaceous boundary regional lithological unit that bridges the temporal gap between the Yanliao biota and the Jehol biota. Tetrapod tracks represent the most significant vertebrate fossil records in the formation, and can be employed to supplement the Late Jurassic fauna and palaeoecological data from northern China. Here, we present a re-analysis of the theropod tracks from the Luofenggou site in northern Hebei Province, utilising an additional 3D model and a locomotory analysis to provide further insights into the ecological context. A morphological analysis indicates that these tracks are more similar to Grallator than to the previously proposed Therangospodus. The latter is diagnosed by coalesced, elongate, oval digital pads lacking a separation in distinct phalangeal pads, whereas these are clearly defined in the presented Tuchengzi material. They can therefore be assigned to the widespread G. ssatoi ichnospecies from the Tuchengzi Formation, although they are longer and more variable in size than other G. ssatoi. A general consideration of speed-related locomotive parameters, trackway morphology, and superposition allows for the speculation of the existence of cooperative or predatory relationships between theropod trackmakers that were differentiated by size or stages of ontogeny, but had similar foot structures.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2384579

ABSTRACT

Tardigrades are a diverse phylum of microscopic invertebrates widely known for their extreme survival capabilities. Molecular clocks suggest that tardigrades diverged from other panarthropods before the Cambrian, but their fossil record is extremely sparse. Only the fossil tardigrades Milnesium swolenskyi (Late Cretaceous) and Paradoryphoribius chronocaribbeus (Miocene) have resolved taxonomic positions, restricting the availability of calibration points for estimating for the origin of this phylum. Here, we revise two crown-group tardigrades from Canadian Cretaceous-aged amber using confocal fluorescence microscopy, revealing critical morphological characters that resolve their taxonomic positions. Formal morphological redescription of Beorn leggi reveals that it features Hypsibius-type claws. We also describe Aerobius dactylus gen. et sp. nov. based on its unique combination of claw characters. Phylogenetic analyses indicate that Beo. leggi and Aer. dactylus belong to the eutardigrade superfamily Hypsibioidea, adding a critical fossil calibration point to investigate tardigrade origins. Our molecular clock estimates suggest an early Paleozoic diversification of crown-group Tardigrada and highlight the importance of Beo. leggi as a calibration point that directly impacts estimates of shallow nodes. Our results suggest that independent terrestrialization of eutardigrades and heterotardigrades occurred around the end-Carboniferous and Lower Jurassic, respectively. These estimates also provide minimum ages for convergent acquisition of cryptobiosis.

LINK(S)

https://www.nature.com/articles/s42003-024-06643-2

https://www.nature.com/articles/s42003-024-06643-2.pdf

ABSTRACT

Recent discoveries of Homo floresiensis and H. luzonensis raise questions regarding how extreme body size reduction occurred in some extinct Homo species in insular environments. Previous investigations at Mata Menge, Flores Island, Indonesia, suggested that the early Middle Pleistocene ancestors of H. floresiensis had even smaller jaws and teeth. Here, we report additional hominin fossils from the same deposits at Mata Menge. An adult humerus is estimated to be 9 − 16% shorter and thinner than the type specimen of H. floresiensis dated to ~60,000 years ago, and is smaller than any other Plio-Pleistocene adult hominin humeri hitherto reported. The newly recovered teeth are both exceptionally small; one of them bears closer morphological similarities to early Javanese H. erectus. The H. floresiensis lineage most likely evolved from early Asian H. erectus and was a long-lasting lineage on Flores with markedly diminutive body size since at least ~700,000 years ago.

LINK(S)

https://www.nature.com/articles/s41467-024-50649-7

https://www.nature.com/articles/s41467-024-50649-7.pdf

ABSTRACT

Tyrannosauroids are a clade of theropod dinosaur taxa which varied greatly in their body size distribution. We investigated the feeding performance of six tyrannosaur genera of variable body size and skull morphology. We used 3D finite element analysis to test whether skull shape becomes more or less resistant to feeding induced forces. Cranial and mandibular models were scaled by adult Tyrannosaurus’s surface area to analyse the influence of shape on skull function. It was found that Tyrannosaurus experienced higher absolute stresses compared to small-bodied relatives. When surface area values were equalized across genera to account for the effect of size and test efficiency of skull shape, smaller individuals experience notably greater stresses than larger relatives due to the robust cranial osteology characterized in the allometry of tyrannosaurids. These results may indicate that the wide crania of tyrannosaurids convey a functional advantage that basal tyrannosauroids, juvenile tyrannosauroids, and alioramins lacked.

LINK(S)

https://www.cell.com/iscience/fulltext/S2589-0042(24)01904-7

ABSTRACT

Hadrosaurid social structure is still poorly understood. Evidence from bonebeds suggests that juvenile individuals of some hadrosaurid species lived apart from herds composed of older individuals, a phenomenon called age segregation. However, the timing at which juvenile individuals became segregated and later rejoined a multigenerational herd is unknown. Three monodominant bonebeds that preserve the remains of multiple individuals of the lambeosaurine hadrosaurid Hypacrosaurus stebingeri at different ontogenetic stages offer an opportunity to better understand the social structure of this species: the Devil's Coulee juvenile hadrosaur bonebed (JBB) from the Oldman Formation of Alberta (Canada) preserves a minimum of four similar-sized late juvenile individuals; the Blacktail Creek North (BCNB) bonebed from the Two Medicine Formation of Montana (USA) preserves a minimum of 23 early juvenile (previously referred to as “nestling”) individuals; and the Lambeosite (LB) bonebed preserves four similar-sized late juvenile individuals and one adult individual. These bonebeds show uniform taphonomic signatures throughout their respective bone assemblages, characterized by little to no weathering and abrasion, uniform style of fracturing, and rare tooth marks on bones. All three bonebeds are interpreted as mass-mortality assemblages. Histological data indicate that the late juvenile individuals from the JBB were three years old at the time of death, similar to the slightly larger late juvenile individuals from the LB, whereas the early juveniles from the BCNB had not yet reached 1 year of age. A taphonomic comparison of the three bonebeds reveal that H. stebingeri individuals lived in age-segregated groups, likely cohorts, until into their fourth year of life when, after having reached sexual maturity, they rejoined a multigenerational herd. The smaller number of individuals preserved in bonebeds representing later ontogenetic stages could reflect a decrease in group size due to high juvenile mortality rate or to higher metabolic needs.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S003101822400405X

ABSTRACT

Notosuchia is a large and diverse clade of Mesozoic crocodyliforms that thrived in continental environments especially during the Cretaceous of Gondwana. This clade has been the focus of several phylogenetic studies that led to the consensus of two main topological arrangements, mostly differing in the position of the clade Sebecidae: the sebecosuchian and sebecian hypotheses. In this manuscript we review the main phylogenetic definitions of several clades of notosuchians in the context of these hypotheses. As a result, besides the clade names previously established under the ICPN/Phylocode (including registration in RegNum) by Ruiz et al. (2021) (Notosuchia, Xenodontosuchia, Sphagesauria, Sphagesauridae) and Darlim et al. (2021a) (Baurusuchia, Baurusuchidae, Baurusuchinae, Pissarrachampsinae), eleven clade names have been registered and are defined in this contribution. Ten of these represent converted clade names (Uruguaysuchidae, Mahajangasuchidae, Peirosauridae, Itasuchidae, Ziphosuchia, Sphagesaurinae, Caipirasuchinae, Sebecia, Sebecosuchia, and Sebecia), while one represents a new clade name (Peirosauria). Furthermore, the definition of Xenodontosuchia is emended (unrestricted emendation) so that the name can be used in the context of a wider array of topologies.

LINK(S)

https://mapress.com/bpn/article/view/bpn.1.3.2

ABSTRACT

The Siwalik Giraffidae fauna is diverse and includes species placed in Sivatheriinae, Giraffinae, and Giraffokeryx. We describe a new genus and species of giraffid, from the Middle Miocene of the Chinji Formation and Nagri Formation in Pakistan. Lyra sherkana gen. et sp. nov. et is unique among the Giraffidae due to the features of its cranial appendages. This taxon possesses a pair of ossicones that are positioned above and slightly medial to the orbits. The ossicones have a unique curvature resembling an ancient Greek harp or lyre, extending outwards and then curving forwards distally with a final backwards twist at the tip. The ossicones have a multi-layered surface. This new species also has large supraorbital sinuses, creating a large boss above the orbit. This last feature is only shared with the later and larger Bramatherium, which is the only giraffid known to also have an enlarged supraorbital boss. This suggests a possible relationship between these two taxa, both present in the Siwaliks, with Bramatherium appearing later than Lyra, during the Late Miocene. The presence of this new taxon increases the diversity not only of the Siwaliks fauna but of the Giraffidae family in general and helps shed light on the poorly known Middle Miocene giraffid faunas.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2365423

ABSTRACT

Take-off is a vital part of powered flight which likely constrains the size of birds, yet extinct pterosaurs are known to have reached far larger sizes. Three different hypothesised take-off motions (bipedal burst launching, bipedal countermotion launching, and quadrupedal launching) have been proposed as explanations for how pterosaurs became airborne and circumvented this proposed morphological limit. We have constructed a computational musculoskeletal model of a 5 m wingspan ornithocheiraean pterosaur, reconstructing thirty-four key muscles to estimate the muscle moment arms throughout the three hypothesised take-off motions. Range of motion constrained hypothetical kinematic sequences for bipedal and quadrupedal take-off motions were modelled after extant flying vertebrates. Across our simulations we did not find higher hindlimb moment arms for bipedal take-off motions or noticeably higher forelimb moment arms in the forelimb for quadrupedal take-off motions. Despite this, in all our models we found the muscles utilised in the quadrupedal take-off have the largest total launch applicable moment arms throughout the entire take-off sequences and for the take-off pose. This indicates the potential availability of higher leverage for a quadrupedal take-off than hypothesised bipedal motions in pterosaurs pending further examination of muscle forces.

LINK(S)

https://peerj.com/articles/17678/

https://peerj.com/articles/17678.pdf

ABSTRACT

Two ammonoids, Guanlingoceras guanlingensis n. gen. n. sp. and Neoprotrachyceras sp. are described from the late early Carnian (Julian 2) Xiaowa Formation of Guizhou province, China. Guanlingoceras guanlingensis n. gen. n. sp. is characterised by ventral spirals which are duplicated with small nodes and robust spines arranged in an alternating pattern. These discoveries further not only enrich the ammonite biodiversity in South China but also indicate the age of Xiaowa Formation should be assigned to Julian 2.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2382230

ABSTRACT

Taphonomy and paleoecology (biological behavior) of the Early Cretaceous fish fossils are poorly described. This study reports for the first time a detailed taphonomical and paleoecological study on Lycoptera in the Mesozoic strata of western Liaoning Province, NE China. The XRD analysis shows that gismondine is the dominant clay minerals that could have contributed to the preservation of Lycoptera fossils and microbial mat fragments in the fossil-bearing horizon. Gismondine may have formed under volcanism-related hydrothermal regime that was transformed from crystal and lithic fragments. The μ-XRF imaging analysis shows a dominant chemical composition of Al, Si, P, S, Rh, K, Ca, Ti, C, Cr, Mn, Fe, Ni, among which P, Ca, C and S are enriched in the fish skeleton in comparison to the matrix. This suggests a dominant apatite composition for the fish skeleton. Hydrothermal influence did not smear off these organic signals probably because of protection of gismondine. The coexistance of C and S with Ni is assumed to represent recovered primary productivity following volcanic explosions and toxic gas emissions. The head of juvenile fish stays close to the body of adult fish. Pending further discoveries, such phenomenon is interpreted to suggest that adult fish actively protected juvenile fish in the presence of environmental pressures such as anoxia and deterioration of water quality induced by volcanism. Ocean acidification and hypoxia in association with volcanism created a harmful environment causing mass extinction of fish. The adult Lycoptera protected their juveniles by its body at the moment before death. Such biological behavior will be increasingly reported given the wide occurrence of Lycoptera in Mesozoic strata.

LINK(S)

https://link.springer.com/article/10.1007/s12583-023-1922-1

ABSTRACT

Turtle tracks are relatively common in Laurasia during the Mesozoic. In Mexico, Cretaceous turtle tracks have been reported in Coahuila, Zacatecas, and Puebla. Here we describe 20 turtle tracks from the Early Cretaceous Jaltepetongo formation of Oaxaca and the Early Cretaceous San Juan Raya Formation of Puebla. The morphology of the tracks shows that the producers were engaged in different activities, such as swimming, bottom walking, or that were partially buoyant. The presence of turtle tracks indicates marginal environments in both geologic formations. The turtle tracks from San Juan Raya in Puebla add to the diverse ichno-assemblage of dinosaur, pterosaur, turtle, and invertebrate tracks that have been already recorded in the area. The turtle tracks from Oaxaca are the most southern in North America of Early Cretaceous age.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0895981124002888

ABSTRACT

The study of new finds of mosasaurids from the Izhberda locality (Southern Urals, Orenburg Region) has made it possible to record for the first time the presence of mosasaurs from the subfamilies Mosasaurinae, Tylosaurinae, and Plioplatecarpinae from the Upper Cretaceous of the Orenburg Region, including representatives of the genera Mosasaurus, Prognathodon, and Clidastes, which are known from the Upper Cretaceous of North America and Western Europe. Of interest is the discovery of the tylosaurine Taniwhasaurus, previously known from New Zealand, Antarctica, South Africa, and Japan. Therefore, the Campanian mosasaurid fauna of the Southern Urals is intermediate and includes North American–European and Asia–Pacific taxa. However, all the finds of mosasaurs from the Izhberda locality can only be identified in open nomenclature, which makes detailed comparisons of the faunas difficult. Revision of the type series of mosasaur Liodon rhipaeus Bogolyubov, 1910 from the Southern Urals has allowed us to conclude that, in addition to the three mosasaurian vertebrae, it includes the ischium and posterior fragment of the mandible of a plesiosaur. Liodon rhipaeus is clearly a nomen dubium and the vertebrae of its type series cannot be identified more precisely than Tylosaurinae indet.

LINK(S)

https://link.springer.com/article/10.1134/S0031030124600355

ABSTRACT

An incomplete skeleton of a large ichthyosaur is described from the Upper Albian Substage of the Mangystau region of Western Kazakhstan. It consists of fragments of cranial bones (including a quadrate bone), fragments of the parietal, supratemporal, and maxillary bones, teeth, and a significant part of the spinal column of 38 vertebrae, as well as fragments of neural arches and ribs. The shape of the quadrate bone and strong teeth with a square root in cross section suggest that this find belongs to the genus Platypterygius.

LINK(S)

https://link.springer.com/article/10.1134/S003103012460029X

ABSTRACT

Old World vultures (Aves: Accipitridae: Gypini) are large diurnal birds of prey, the characteristic inhabitants of open biotopes in Africa and southern Eurasia. Fossil remains of vultures are rather rare; the evolution of the group is poorly studied. This article describes the skull and tarsometatarsus of the large vulture Torgos platycephalus sp. nov. from the Upper Pleistocene of the Binagadi locality (Azerbaijan). This is the first fossil record of the genus in the Caucasus and second confirmed record outside its current range (Torgos sp. is also known from the Middle Pleistocene of China). The coexistence of three species of large scavengers in the Late Pleistocene of the Absheron Peninsula (in addition to Torgos platycephalus, Aegypius monachus and Gyps fulvus are also known from the Binagadi locality) can be explained by the richness of the food supply, which included a noticeable diversity of large mammals.

LINK(S)

https://link.springer.com/article/10.1134/S0031030124600367

ABSTRACT

Mollusca is one of the most diverse extant phyla, with forms varying widely from bivalves such as clams to snaily gastropods and highly complex cephalopods such as octopuses. Zhang et al. describe a new fossil, Shishania aculeata, from the Cambrian Period that displays basal molluscan traits, such as a foot and mantle, as well as traits that are more characteristic of other members of their superphylum, Lophotrochozoa. The authors place this taxon as a stem mollusk covered in sclerites, suggesting that it was intermediate in form between members of Lophotrochozoa and the soon to develop and diversify crown mollusks. —Sacha Vignieri

LINK(S)

https://www.science.org/doi/10.1126/science.ado0059

ABSTRACT

Notosuchia is a group of crocodyliforms with mostly terrestrial habits that lived during the Mesozoic and up to the Miocene. Within this group Uruguaysuchidae is so far represented by eight species, six of them clustered in the genus Araripesuchus. Two species of this genus, A. patagonicus and A. buitreraensis, come from different localities in Patagonia (Argentina) from the Candeleros Formation (Cenomanian age). Here we present a third species of Araripesuchus from this formation. The new species comes from the same locality as Araripesuchus buitreraensis, but differs in numerous features including the presence of different molariform teeth. The new species was included in a phylogenetic analysis and, in agreement with previous analyses, Uruguaysuchidae is recovered as monophyletic and placed within Notosuchia as the sister clade of Peirosauridae. Uruguaysuchidae includes all species of Araripesuchus as well as Anatosuchus minor and Uruguaysuchus aznarezi. The new species adds new information to the ecological diversity of the group its bulbous molariforms with a quadrangular occlusal surface bounded by mamelons is interpreted as indicative of a durophagous diet, suggesting the presence of niche partitioning between the two sympatric species A. manzanensis and A. buitreraensis.

LINK(S)

https://www.tandfonline.com/doi/full/10.1080/14772019.2024.2373987