The first late cretaceous mawsoniid coelacanth (Sarcopterygii: Actinistia) from North America: Evidence of a lineage of extinct ‘living fossils’

Today, the only living genus of coelacanth, Latimeria is represented by two species along the eastern coast of Africa and in Indonesia. This sarcopterygian fish is nicknamed a "living fossil", in particular because of its slow evolution. The large geographical distribution of Latimeria may be a reason for the great resilience to extinction of this lineage, but the lack of fossil records for this genus prevents us from testing this hypothesis. Here we describe isolated bones (right angular, incomplete basisphenoid, fragments of parasphenoid and pterygoid) found in the Cenomanian Woodbine Formation in northeast Texas that are referred to the mawsoniid coelacanth Mawsonia sp. In order to assess the impact of this discovery on the alleged characteristic of "living fossils" in general and of coelacanths in particular: 1) we compared the average time duration of genera of ray-finned fish and coelacanth in the fossil record; 2) we compared the biogeographic signal from Mawsonia with the signal from the rest of the vertebrate assemblage of the Woodbine formation; and 3) we compared these life traits with those of Latimeria. The stratigraphical range of Mawsonia is at least 50 million years. Since Mawsonia was a fresh, brackish water fish with probably a low ability to cross large sea barriers and because most of the continental components of the Woodbine Fm vertebrate assemblage exhibit Laurasian affinities, it is proposed that the Mawsonia’s occurrence in North America is more likely the result of a vicariant event linked to the break-up of Pangea rather than the result of a dispersal from Gondwana. The link between a wide geographic distribution and the resilience to extinction demonstrated here for Mawsonia is a clue that a similar situation existed for Latimeria, which allowed this genus to live for tens of millions of years.

Vertebrate Palaeoecology of the Pisco Formation (Miocene, Peru): Glimpses into the Ancient Humboldt Current Ecosystem

The northward-flowing Humboldt Current hosts perpetually high levels of productivity along the western coast of South America. Here, we aim to elucidate the deep-time history of this globally important ecosystem based on a detailed palaeoecological analysis of the exceptionally preserved middle–upper Miocene vertebrate assemblages of the Pisco Formation of the East Pisco Basin, southern Peru. We summarise observations on hundreds of fossil whales, dolphins, seals, seabirds, turtles, crocodiles, sharks, rays, and bony fishes to reconstruct ecological relationships in the wake of the Middle Miocene Climatic Optimum, and the marked cooling that followed it. The lowermost, middle Miocene Pisco sequence (P0) and its vertebrate assemblage testify to a warm, semi-enclosed, near-shore palaeoenvironment. During the first part of the Tortonian (P1), high productivity within a prominent upwelling system supported a diverse assemblage of mesopredators, at least some of which permanently resided in the Pisco embayment and used it as a nursery or breeding/calving area. Younger portions of the Pisco Formation (P2) reveal a more open setting, with wide-ranging species like rorquals increasingly dominating the vertebrate assemblage, but also local differences reflecting distance from the coast. Like today, these ancient precursors of the modern Humboldt Current Ecosystem were based on sardines, but notably differed from their present-day equivalent in being dominated by extremely large-bodied apex predators like Livyatan melvillei and Carcharocles megalodon.

The Early Pleistocene ectothermic vertebrates of Pietrafitta (Italy) and the last Western European occurrence of Latonia Meyer, 1843

The Early Pleistocene site of Pietrafitta (central Italy) produced a rich vertebrate assemblage from the Late Villafranchian Land Mammal Age (late MN18). Geological and paleobotanical data from Pietrafitta indicate a lacustrine environment, surrounded by a humid deciduous broadleaved forest with a temperate climate. The vertebrate assemblage consists of at least 40 taxa including actinopterygians, amphibians, reptiles, birds, and mammals. Here, we concentrate on the ichthyofaunal and herpetofaunal remains. The ichthyofauna includes Barbus Cuvier and Cloquet, 1816, Scardinius Bonaparte, 1837, aff. Squalius Cuvier, 1817, and Tinca Cuvier, 1817. The two anuran genera are the large-sized alytid frog Latonia Meyer, 1843 and the “green frog” Pelophylax Fitzinger, 1843. Three snake precloacal vertebrae were recognized, one attributed to Colubrines indet., another one to ­Natrix sp. Laurenti, 1768, and the largest and most complete vertebra is referred to the genus Vipera s.l. Laurenti, 1768 (cf. gr. “Oriental vipers”). The chelonian fossils, including some complete carapaces and plastrals, are attributed to the European pond turtle (Emys gr. Orbicularis Linnaeus, 1758) and Hermann’s tortoise (Testudo hermanni Gmelin, 1789).

The vertebrate fossil collection record from the Chinchilla Sand, South–East Queensland, 1844-2021

Since the mid-1840s a diverse fossil vertebrate assemblage, referred to as the Chinchilla Local Fauna, has been collected from the Pliocene deposits of the Chinchilla Sand on the western Darling Downs of South-East Queensland. In large part because of this long history and the numerous collectors who have worked fossil deposits in the area, much ambiguity regarding site and locality names and their specific coordinates exists. Here, we review the vertebrate fossil collection records in the Queensland Museum Fossil, Donor, Collector and Locality Registers, correspondence, and field notes in an effort to pinpoint the location of each named locality and site and develop a digital map which highlights the historical collecting sites at one significant locality in the Chinchilla area. To ensure that a systematic framework for all future collecting from the main collecting area (Chinchilla Rifle Range) is maintained, we recommend the use of consistent nomenclature for sites so that spatial information of the highest possible quality is captured into the future. We recommend future collections include detailed recordings of stratigraphic contexts as well as GPS coordinates.

Diverse vertebrate assemblage of the Kilmaluag Formation (Bathonian, Middle Jurassic) of Skye, Scotland

ABSTRACT The Kilmaluag Formation on the Isle of Skye, Scotland, provides one of the richest Mesozoic vertebrate fossil assemblages in the UK, and is among the richest globally for Middle Jurassic tetrapods. Since its discovery in 1971, this assemblage has predominantly yielded small-bodied tetrapods, including salamanders, choristoderes, lepidosaurs, turtles, crocodylomorphs, pterosaurs, dinosaurs, non-mammalian cynodonts and mammals, alongside abundant fish and invertebrates. It is protected as a Site of Special Scientific Interest and by Nature Conservancy Order. Unlike contemporaneous localities from England, this assemblage yields associated partial skeletons, providing unprecedented new data. We present a comprehensive updated overview of the Kilmaluag Formation, including its geology and the fossil collections made to date, with evidence of several species occurrences presented here for the first time. We place the vertebrate faunal assemblage in an international context through comparisons with relevant contemporaneous localities from the UK, Europe, Africa, Asia and the US. This wealth of material reveals the Kilmaluag Formation as a vertebrate fossil assemblage of global significance, both in terms of understanding Middle Jurassic faunal composition and the completeness of specimens, with implications for the early evolutionary histories of mammals, squamates and amphibians.

Oldest co-occurrence of Varanus and Python from Africa—first record of squamates from the early Miocene of Moghra Formation, Western Desert, Egypt

Lizard and snake remains from the early Miocene (Burdigalian) of the Moghra Formation, Egypt, are described herein. This material comprises the first fossil remains of squamates recovered from the otherwise rich and well known vertebrate assemblage of Moghra. The material pertains to two different genera, the varanid lizard Varanus and the pythonid snake Python and adds to the so far rather poorly known squamate fossil record from Africa. On the basis of the new remains, Moghra marks the oldest so far described co-occurrence of Varanus and Python in the African continent. The close sympatry of these two genera in the African fossil record is thoroughly analyzed and discussed, a co-existence, which is still widespread in the extant herpetofauna of the continent. Situated rather close to the so called “Levantine Corridor” and dated at the Burdigalian, practically when Afro-Arabia collided with Eurasia, the Moghra squamate assemblage offers the potential of important insights in the biogeography and dispersal events of vertebrate groups during the early Miocene.