PALEONTOLOGY IN JUNE, 2025

ABSTRACT

While reporting on the mosasaurid fauna of the upper Demopolis Chalk of western Alabama and northeastern Mississippi, Derstler (1988) noted the presence of numerous remains of Plioplatecarpus sp. and Mosasaurus conodon, and a single isolated tooth of Prognathodon cf. Prognathodon solvayi. These remains are of Late Campanian age, originating from within a few meters of the lower boundary of the Bluffport Marl Member.

LINK(S)

https://www.mapress.com/mz/article/view/mesozoic.2.2.2

ABSTRACT

A nearly complete and relatively well-preserved skeleton of the giant ground sloth Megatherium sp. in the hyperarid core of the Atacama Desert reveals how climate related taphonomic processes drastically transformed these remains over time. The individual, semi-exposed in situ by wind erosion, was found in late Pleistocene palaeowetland sediments that formed during the Central Andean Pluvial Event. Several radiocarbon dates on bone bioapatite and carbonate tufas date the specimen to c. 16 500 cal yr BP. Physical, organic, and inorganic traces were identified using histotaphonomic, mineralogical, and microscopic analyses (optical, scanning electron and petrographic microscopy, x-ray diffraction and FTIR-ATR). Surficial bones with rounded, polished surfaces due to wind erosion are well preserved, while buried bones are poorly preserved and structurally weak due to an early phase of bioerosion, which was followed by desiccation revealed by micro-cracks. Iron and manganese were deposited under anoxic conditions, followed by carbonates such as sparite and micrites, which formed due to a drier context, resulting in the encrustation of these bones by halite and calcium sulfates in hyperarid conditions that continue to this day. These observations imply that the ground sloth lived in a much wetter environment compared to today and its remains were subsequently affected by anaerobic wet cycles, an oxidizing sedimentary environment, and later an oxidizing hyperarid climate. In summary, the unravelled histotaphonomy is written in small fractions of bones which emerge as new proxies for understanding the complex palaeoclimatic history of the Atacama Desert.

LINK(S)

https://onlinelibrary.wiley.com/doi/10.1111/pala.70011

https://onlinelibrary.wiley.com/doi/pdf/10.1111/pala.70011

ABSTRACT

An exceptional specimen of Rehmannia (Loczyceras) is described in this work. Its body chamber includes two paired aptychi that according to its morphological characteristics correspond to Praetriaptychus (typical of Perisphinctidae). The ammonoid comes from the municipality of Quintanas de Hormiguera (Palencia, Spain), and although its precise stratigraphic position is unknown, considering the taxonomic identification it is most likely that it corresponds to Callovian materials. The presence of aptychi inside the body chamber in approximately original anatomical position with this type of taphonomic conservation is rare in the fossil record. On the other hand, the type of function that these anatomical pieces had is a highly discussed topic in the literature that arouses significant interest. From educational or dissemination approaches, it can also be considered a highly interesting example since it allows to communicate the anatomical characteristics of these extinct organisms to society. These types of palaeontological elements and their great value in actions related to Geodiversity can be utilized as formal or non-formal ex situ educational tools.

LINK(S)

https://link.springer.com/article/10.1007/s41513-025-00303-y

ABSTRACT

The theropod dinosaur clade Spinosauridae lived on almost all continents during the Cretaceous. It has been suggested that the group originated in Laurasia, likely in Europe. Asian spinosaurid fossils have been discovered in Southeast and East Asia, particularly from Barremian–Aptian deposits of the Early Cretaceous, with some additional evidence from Cenomanian-aged sediments in the Late Cretaceous. The presence of this theropod clade in Asia, including Thailand, Malaysia, Laos, China, and Japan, may have been influenced by the regression of the Uralian seaway, which temporarily connected Europe and Asia via an ephemeral landbridge. This change likely affected the dispersal of spinosaurids from Europe, facilitating their spread across Asia and shaping their evolution through geographic vicariance. This study reviews the Asian fossil record of Spinosauridae to examine their emergence, paleogeographic distribution, and dispersal patterns. The reports of Asian spinosaurids suggested that the distribution of this clade in Asia is complex and dubious due to the incompleteness of materials and uncertainty of the age of several fossil-bearing strata. The spinosaurid ancestors dispersed along the coastal shoreline from Europe by crossing ephemeral landbridge during pre-Barremian. Then, they spread out to Thailand, Malaysia, southern China, and Japan. The presence of Late Cretaceous spinosaurids in China suggests that Asian spinosaurids persisted until the extinction event of this clade, as happened in western Laurasia and Gondwana during the Cenomanian.

LINK(S)

https://ph03.tci-thaijo.org/index.php/TGJ/article/view/3652

ABSTRACT

Cephalopods are one of the most successful marine invertebrates in modern oceans, and they have a 500-million-year-old history. However, we know very little about their evolution because soft-bodied animals rarely fossilize. Ikegami et al. developed an approach to reveal squid fossils, focusing on their beaks, the sole hard component of their bodies. They found that squids radiated rapidly after shedding their shells, reaching high levels of diversity by 100 million years ago. This finding shows both that squid body forms led to early success and that their radiation was not due to the end-Cretaceous extinction event. —Sacha Vignieri

LINK(S)

https://www.science.org/doi/10.1126/science.adu6248

ABSTRACT

Although their remains have been known since the 1870s, the small, bipedal ornithischian dinosaurs from the Upper Jurassic Morrison Formation of the western USA remain poorly known. The historic type specimens are incomplete and poorly preserved and have recently been designated as nomina dubia. Here, we describe a recently collected, partial but three-dimensionally preserved skeleton of a new small-bodied ornithischian from the Morrison Formation of Colorado, USA, that we name Enigmacursor mollyborthwickae gen. et sp. nov. The skeleton includes substantial portions of the axial and appendicular skeleton and, when scored into a phylogenetic analysis, is shown to be a non-cerapodan neornithischian, whose closest relative is Yandusaurus hongheensis from the Late Jurassic of China. The discovery of Enigmacursor enhances the diversity of ornithischian dinosaurs from the Morrison Formation and provides new information on their anatomy. In addition, it demonstrates that there is additional cryptic diversity of small-bodied Morrison Formation ornithischians, suggesting they were a more diverse component of these Late Jurassic ecosystems than was previously realized.

LINK(S)

https://royalsocietypublishing.org/rsos/article/12/6/242195/235406/Enigmacursor-mollyborthwickae-a-neornithischian

ABSTRACT

This report is about the first record of non-avian dinosaur eggs in the Hefei Basin, Anhui Province, China. Based on the combination of elongated egg body, linear ridges on the outer surface and two structure layer, the eggs can be referred to Elongatoolithidae. The gradual boundary between the cone and the column layers as well as the relative thin eggshell (less than 1 mm) indicates its affinity within Elongatoolithus. The eggs are identified as Elongatoolithus oosp., as they were severely compressed and experienced erosion on both inner and outer surfaces. The discovery of egg fossil in the Hefei Basin offers evidence for stratum comparison in this region and supplements the diversity of egg fossils in Anhui. Meanwhile, this discovery also enriches the paleogeographic distribution of elongatoolithids.

LINK(S)

https://www.vertpala.ac.cn/EN/10.19615/j.cnki.2096-9899.250618

ABSTRACT

Monstersauria (Squamata, Anguimorpha) fossils are present in most Upper Cretaceous sedimentary basins in western North America, but despite almost a century of collection, their record remains extremely fragmentary. Here, we describe new material belonging to large-bodied monstersaurs, including a new taxon, Bolg amondol gen. et sp. nov., based on a fragmentary associated skeleton and co-occurring specimens from the middle unit of the upper Campanian Kaiparowits Formation of Grand Staircase–Escalante National Monument in southern Utah, USA. Phylogenetic analyses recover B. amondol within Monstersauria, with two unique anatomical features: fused osteoderms on the jugal and the presence of autotomy septa on the distal caudal vertebrae. Critically, B. amondol is morphologically distinct from the problematic Late Cretaceous North American monstersaur Palaeosaniwa canadensis, whereas co-occurring monstersaur vertebrae and parietals from the Kaiparowits Formation (cf. P. canadensis) highlight a pressing need for a reassessment of this important, widespread taxon. These results offer new evidence that at least three lineages of distinct, large-bodied monstersaurian lizard were present on the palaeolandmass of Laramidia during the Campanian Stage. Importantly, B. amondol represents the most complete squamate recovered from late Campanian southern Laramidia and reveals key anatomical characteristics for future identification of isolated lizard fossil elements.

LINK(S)

https://royalsocietypublishing.org/doi/10.1098/rsos.250435

ABSTRACT

We describe the most complete ichthyosaur skeleton so far known from the Early Jurassic of North America. The specimen is from the lower Fernie Formation, near the townsite of Fernie, British Columbia. The local strata are poorly exposed, hampering more precise stratigraphic correlation. Ammonites associated with the specimen suggest an Early Pliensbachian age. The specimen, although poorly preserved, displays a unique combination of characters sufficient to designate a new genus and species, Fernatator prenticei gen. et sp. nov. It is characterized by a tall, bar-like postorbital, a short, straight jugal that does not extend beyond the orbit anteriorly or posteriorly, a long, narrow anterior process of the maxilla, and a coracoid with a broadly curved lateral edge and a deep anterior notch, among other features. It represents an important addition to the meagre North American record of Early Jurassic ichthyosaurs and the second taxon to be recognized from the Early Jurassic of Canada.

LINK(S)

https://www.researchgate.net/figure/Detailed-skull-anatomy-of-CMNFV-40398-Fernatator-prenticei-gen-and-sp-nov-A_fig3_392596228

ABSTRACT

Eutyrannosaurians were large predatory dinosaurs that dominated Asian and North American terrestrial faunas in latest Cretaceous times. These apex predators arose from smaller-bodied tyrannosauroids during the ‘middle’ Cretaceous that are poorly known owing to the paucity of fossil material. Here we report on a new tyrannosauroid, Khankhuuluu mongoliensis gen. et sp. nov., from lower Upper Cretaceous deposits of Mongolia that provides a new perspective on eutyrannosaurian origins and evolution. Phylogenetic analyses recover Khankhuuluu immediately outside Eutyrannosauria and recover the massive, deep-snouted Tyrannosaurini and the smaller, gracile, shallow-snouted Alioramini as highly derived eutyrannosaurian sister clades. Khankhuuluu and the late-diverging Alioramini independently share features related to a shallow skull and gracile build with juvenile eutyrannosaurians, reinforcing the key role heterochrony had in eutyrannosaurian evolution. Although eutyrannosaurians were mainly influenced by peramorphosis or accelerated growth, Alioramini is revealed as a derived lineage that retained immature features through paedomorphosis and is not a more basal lineage as widely accepted. Our results reveal that Asian tyrannosauroids (similar to Khankhuuluu) dispersed to North America, giving rise to Eutyrannosauria in the mid-Late Cretaceous. Eutyrannosauria diversified and remained exclusively in North America until a single dispersal to Asia in the latest Cretaceous that established Alioramini and Tyrannosaurini. Stark morphological differences between Alioramini and Tyrannosaurini probably evolved due to divergent heterochronic trends—paedomorphosis versus peramorphosis, respectively—allowing them to coexist in Asia and occupy different ecological niches.

LINK(S)

https://www.nature.com/articles/s42003-025-07653-4

https://www.nature.com/articles/s42003-025-07653-4.pdf

ABSTRACT

Rebbachisaurids are medium to large-sized, non-selective and ground-level browser diplodocoid sauropods, and they are characterised by highly specialised skulls, widely pneumatized axial elements and gracile appendicular skeletons. Known from the Early Cretaceous to the early Late Cretaceous, the rebbachisaurid fossil record is particularly diversified in Gondwana, with several specimens found in North Africa and South America. Notably, Patagonia has yielded over more than half of all known Rebbachisauridae, including the most basal forms and the youngest rebbachisaurid remains to date. Herein, we describe a new species of Rebbachisauridae from the Huincul Formation (upper Cenomanian) of the Neuquén Basin (Patagonia, Argentina): Astigmasaura genuflexa gen. et sp. nov. New laboratory work provided the complete osteology of the specimen MAU-Pv-EO-629, complementing the previously published hind limb anatomy (Bellardini et al., 2024). Thus, the type material of Astigmasaura comprises the posterior portion of an articulated, postcranial skeleton of a single, morphologically adult individual. Astigmasaura shares different conditions with other Rebbachisauridae, including anterior caudal vertebrae with tall neural spines and tetraradiate neural laminae, asymmetric middle haemal arches, mediolaterally compressed proximal tibiae, and femur with medially inclined distal condyles. Furthermore, Astigmasaura shows a unique combination of diagnostic features that distinguish it from all other sauropods. This new record not only provides new morphological information about the caudal and pelvic girdle anatomy of Rebbachisauridae, which is poorly known to date, and suggests a greater taxonomic diversification within the family during the last stages of its evolutionary history than known before.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667125001119?via%3Dihub

ABSTRACT

Sauropod dinosaurs were abundant and diverse across much of the globe throughout the Jurassic and Cretaceous periods and include the largest terrestrial animals of all time. Since the discovery of the first near-complete skeletons in the late 19th century, sauropods have been almost universally interpreted as herbivorous. However, our concept of their diet is based on indirect evidence and inference since no sauropod fossilized gut contents (cololites) are known. Here, we describe a cololite associated with a specimen of the sauropod Diamantinasaurus matildae from the mid-Cretaceous (∼101–94 Ma) Winton Formation of Queensland, Australia. The cololite is hosted within an indurated rock layer, localized to the abdominal region, and closely and consistently associated with a layer of mineralized skin. Conifer pinnules, angiosperm leaves, and seed-fern fruiting bodies are preserved within, as are chemical biomarkers consistent with gymnosperms and angiosperms. This Diamantinasaurus cololite provides the first direct, empirical evidence in sauropods of herbivory, demonstrating generalist feeding, low- to high-level browsing, and minimal oral processing of food. The longevity of the clade Sauropoda was underpinned by the persistence through time of generalist feeders like Diamantinasaurus that were capable of feeding at a range of heights on a variety of different plant species.

LINK(S)

https://www.cell.com/current-biology/fulltext/S0960-9822(25)00550-0

https://www.cell.com/action/showPdf?pii=S0960982225005500

ABSTRACT

The Javan rhino is a critically endangered species that has become extinct in several Asian countries, including Thailand. There are three Javan rhino subspecies: Rhinoceros sondaicus sondaicus, R. s. annamiticus, and R. s. inermis, and the first two subspecies existed in Thailand decades ago. However, no genetic study on Thai rhinos has been reported. In this study, we amplified a partial D-loop region of two ancient rhino specimens dated to approximately 100 years before present, from southwest Thailand. Then, we constructed phylogenetic trees and a haplotype network based on the D-loop sequences of the Thai rhinos and 39 Javan, Sumatran, and Indian rhinos from the GenBank database. The ancient Thai rhino DNA belonged to Javan rhinos and was clearly separated from R. s. annamiticus and R. s. sondaicus. The nucleotide differences among the ancient Thai, R. s. annamiticus, and R. s. sondaicus rhino DNA were 5.14–8.30%, similar to those between two white rhino subspecies. Moreover, species delimitation analyses confirmed that the ancient Thai rhinos should belong to another Javan rhino subspecies, possibly the extinct Indian Javan rhino. This is the first report of rhino DNA from Thailand and possibly the Indian Javan rhino DNA, which could be used for evolutionary studies.

LINK(S)

https://www.mdpi.com/2076-2615/15/12/1678

ABSTRACT

The discovery in 1938 of a living coelacanth, Latimeria chalumnae, triggered much research and discussion on the evolutionary history and phylogeny of these peculiar sarcopterygian fishes. Indeed, coelacanths were thought to represent the ‘missing link’ between fishes and tetrapods, a phylogenetic position which is now dismissed. Since the first analyses using a phylogenetic approach were carried out three decades ago, a relatively similar data matrix has been consistently used by researchers for running analyses, with no significant changes aside from the addition of new taxa and characters, and minor corrections to the states’ definition and scorings. Here, we investigate the phylogeny of Actinistia with an updated data matrix based on a list of partially new or modified characters. From the initial list of characters available in the most recent studies, we removed 16 characters, modified 16 other characters’ definition and added 18 new characters, resulting in a list of 112 characters. We also revised the data matrix by correcting 171 miscoding found for 37 taxa. Based on the new phylogeny, we propose a new classification of coelacanths including 46 coelacanth genera, part of them allocated within nine families and four sub-families. Most of these groups were already named but were not recognised as clades, or poorly or not diagnosed in previous phylogenetic analyses. We provide several new or emended diagnoses for each clade. For the first time, a set of Palaeozoic coelacanth genera are found gathered within a clade, namely the Diplocercidae. All Mesozoic coelacanths, including extant Latimeria, are resolved as members of the order Coelacanthiformes, a clade that arose in the Permian, with Coelacanthus diverging first. We also found that most Mesozoic coelacanths are gathered into a clade, the Latimerioidei, itself divided into the Latimeriidae and the Mawsoniidae, each of which is divided into two subfamilies. Although these important changes, the new phylogeny of the Actinistia shows no significant alteration, and it remains relatively similar compared to previous studies. This demonstrates that the coelacanth phylogeny is now rather stable despite the weak support for most nodes in the phylogeny, and despite the difficulty of defining relevant morphological characters to score in this relatively slowly evolving lineage.

LINK(S)

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0320214

ABSTRACT

The so-called “Solnhofen limestones” of southern Germany are widely recognized for their abundance of Late Jurassic fossil vertebrates, with pterosaurs being no exception. Within the recognized plenitude of the pterosaurs within this assemblage, although ctenochasmatid remains are relatively abundant, gnathosaurines are scarce, with only one known Solnhofen representative of the group known thus far. The Late Kimmeridgian locality of Brunn (near Regensburg, Germany) represents the oldest locality of the Solnhofen complex (“Solnhofen Archipelago” in recent literature), with only one pterosaur having been described from this locality to date. Here, a second pterosaur taxon from within this locality and a new gnathosaur is introduced, Spathagnathus roeperi gen. et sp. nov., whose novel tooth and dental enamel features add to the known dental diversity for the group. The new taxon represents the oldest occurrence of a gnathosaurine and contributes to the paleoenvironmental stratigraphic range for the Gnathosaurinae within the overall fossil assemblage of the Solnhofen Archipelago. Furthermore, the new taxon adds to the known diversity of ctenochasmatids in the Late Jurassic and underlines the importance of this early radiation of pterodactyloid pterosaurs during this time.

LINK(S)

https://link.springer.com/article/10.1007/s12542-025-00725-0

https://link.springer.com/content/pdf/10.1007/s12542-025-00725-0.pdf

ABSTRACT

Diverse and abundant continental vertebrate assemblages are known from the Upper Cretaceous (Campanian–Maastrichtian) of several European countries. They formed on an island archipelago and are marked by their distinctive combination of unusual endemic groups and immigrants from North America, Asia and Gondwana. Although dinosaur fossils have been described from nearby Bulgaria, body fossils of continental vertebrates were previously unknown from the Mesozoic of Serbia. Here, we describe the dinosaurian component of a new vertebrate assemblage from the uppermost Cretaceous (Maastrichtian) of Osmakovo in southeastern Serbia. A single larger bone represents the partial left ulna of a sauropod dinosaur. Its anatomy is suggestive of titanosaurian affinities, although it appears distinct from the titanosaurs Magyarosaurus and Petrustitan from the Maastrichtian of Romania. The small size of this element may indicate its juvenile nature or that it represents an island dwarf similar to Magyarosaurus, but distinguishing these possibilities will require histological work. Sixteen isolated theropod teeth, some incomplete, were recovered by screenwashing and studied using comparative anatomy and machine learning analysis. Nine of these teeth are referred to Dromaeosauridae based on both approaches. Three teeth that are strongly recurved and lack serrations were identified as Aves by machine learning but might alternatively represent dromaeosaurid premaxillary teeth and are thus referred to Paraves. The remaining teeth comprise one specimen of the enigmatic Paronychodon and three too poorly preserved to identify beyond Theropoda. This assemblage shows similarities to contemporaneous assemblages from Romania and suggests the potential for further discoveries in the Mesozoic of Serbia.

LINK(S)

https://www.sciencedirect.com/science/article/abs/pii/S0195667125001004

ABSTRACT

Pareiasauria are a specialized clade of herbivorous tetrapods that existed throughout Pangaea during the middle–late Permian period. The phylogenetic relationships of Chinese pareiasaur species have remained controversial for several decades, primarily due to the poor preservation of the known specimens. For example, until the report of Shihtienfenia completus in 2019, no complete skull had been documented for Chinese pareiasaurs. The present study describes a mid-sized pareiasaur, Yinshanosaurus angustus gen. et sp. nov., based on a nearly complete skull and an articulated partial postcranial skeleton collected from the Naobaogou Formation in 2018. It presents several significant new morphological features such as the narrowest skull of all pareiasaurs, with skull length more than twice skull width at the lateral edges of the cheeks (quadratojugals), a forked nasal posterior projection, a notch on the tabular posterior margin, and a unique combination of characters: U-shaped paraoccipital process, snout as wide as high, long frontal with a length-to-width ratio greater than 2.0, and maxillary teeth oriented vertically. Although the phylogenetic framework of pareiasaurs still requires further refinement, the current analysis yields three distinct phylogenetic positions for the Chinese pareiasaurs and establishes a new clade including S. completus and Y. angustus.

LINK(S)

https://onlinelibrary.wiley.com/doi/10.1002/spp2.70020

ABSTRACT

Allosauroids were apex predators in many terrestrial ecosystems from the Early to early Late Cretaceous. Despite this, the only formally described allosauroid taxa from Cretaceous North America are Acrocanthosaurus of the Antlers Formation of Oklahoma, and the highly fragmentary Siats from the Cedar Mountain Formation of Utah. This lack of known allosauroids is especially apparent in the Yellow Cat Member of the Cedar Mountain Formation, based on the rarity of reported bones and absence of named taxa. However, their presence has previously been inferred by shed teeth from the lower portion of the Yellow Cat. Here we report on likely allosauroid teeth from three localities, Grayash, Blane II, and Doelling′s Bowl, in the Yellow Cat Member of the Cedar Mountain Formation, the former two localities being in the upper portion of the Yellow Cat which until now has not produced any allosauroid remains, at least not any reported in scientific literature. We also assess teeth tentatively identified as Acrocanthosaurus from the Long Walk Quarry in the Ruby Ranch Member of the Cedar Mountain Formation, and the Sonorasaurus Quarry in the Turney Ranch Formation of Arizona. Principal component analysis of linear and geometric morphometrics supports these teeth as being from allosauroids and specifically within Carcharodontosauria, making the Yellow Cat teeth the earliest reported evidence of carcharodontosaurs in North America. Furthermore, their co-occurrence with Utahraptor confirms that multiple large predators lived in this environment and suggests that North American allosauroids did not yield the entire predatory niche to other theropods until their extinction in the Cenomanian-Turonian ages. Lastly, the teeth from the different Yellow Cat Member localities appear morphometrically distinct from each other, suggesting that each may represent a different taxon, though small sample size prohibits a definitive statement on this. While the Arizona Acrocanthosaurus tooth may belong to a species of Acrocanthosaurus, the Long Walk teeth differ from Acrocanthosaurus atokensis in having significantly lower denticle density, and may represent a new taxon. We conclude that there may be as many as four carcharodontosaurid theropod taxa in the Cedar Mountain Formation, thus, the diversity of allosauroids in Early Cretaceous North America is likely greater than previously recognized.

LINK(S)

https://bioone.org/journals/journal-of-the-arizona-nevada-academy-of-science/volume-50/issue-2/036.050.0204/Here-be-Dragons--Shed-Teeth-Potentially-Indicate-the-Presence/10.2181/036.050.0204.short

ABSTRACT

The sabre-toothed cat Smilodon fatalis (Leidy, 1868) was an iconic predator in the Americas during the Ice Age. While its distribution in North America is abundant, its record in South America is very scarce and is restricted to only a few locations. In the present contribution a new skull assigned to Smilodon fatalis is described. The specimen comes from the Dolores Formation (late Pleistocene–early Holocene, Lujanian Stage/Age) in southern Uruguay. This skull is elongated and narrow in its general shape; its nasals are not markedly high and, in the posterior part, the large lambdoid crest is anteroventrally straight, converging in the same plane with the mastoid process, characteristics observed in S. fatalis that clearly differentiate it from Smilodon populator Lund, 1842. Body mass estimations, according to allometric equations for extant felids, and the quantitative analyses (bivariate graphs) provide results consistent with the aforementioned taxonomic assignment. Based on this finding, which turns out to be, to date, the southernmost record for this species in the Americas, some paleobiogeographic and taxonomic implications in a regional context are discussed.

LINK(S)

https://cdnsciencepub.com/doi/10.1139/cjes-2024-0137

ABSTRACT

The fossil record of Arthropleura, distributed in the Nord-Pas-de-Calais coalfield (France) and some Belgian localities, is reassessed and compared to new material discovered in new localities of the Bruay Formation. Based on tergite ornamentation, the Bruay specimens are attributed to Arthropleura mammata. Two specimens are preserved with their head, allowing the description of the head anatomy of this species for the first time. We estimated the size of the most complete remains from the newly investigated localities, with a maximum length probably reaching 50 centimetres. The geographical extension of A. mammata can be extended to the Nord-Pas-de-Calais and to the Saarland coal basins. Some specimens from the Bruay Formation consist of K-plates, typical ventral plates of arthropleurids displaying well-preserved pierced tubercules. These pierced tubercules are also found in K-plates of Arthropleura cristata, found in the Mazon Creek Lagerst¨atte, and could represent spiracles similar to the ones found in millipedes. This suggests that Arthropleura possessed a tracheal system for respiration and, combined with other anatomical factors, would confirm it as a terrestrial arthropod.

LINK(S)

https://www.openpalaeo.org/article/view/6970