Continental Vertebrate Research Articles

Pliocene facies and fossil contents of Qaret El-Muluk formation at Wadi El-Natrun depression, Western Desert, Egypt

A sequence of late Pliocene sediments (Qaret El-Muluk Formation) covers large areas within Wadi El-Natrun depression; at the western periphery of the Nile Delta. The exposed sequence is composed of friable sands. mudstones, shales and minor limestones with combined total thickness of approximately 50 m. The fossil content consists of fresh and brackish water elements; charophytes, ostracods, gastropods, oysters and benthonic foraminifera. Planktonic forams which suggest marine influence have been also recorded. Terrestrial and aquatic continental vertebrate fauna includes mammals, reptiles, fish and aves. Several subtypes of ichthyoliths have been discovered in this study.

Late Cretaceous non-marine vertebrates from southern France: A review of recent finds

During the last few years, systematic prospections and excavations in the non-marine Campanian andMaastrichtian of southern France, from Provence in the East to the valley of the Garonne in the West, have considerably increased our knowledge of the continental vertebrates (fishes, amphibians, turtles, squamates, crocodilians, pterosaurs, dinosaurs, birds and mammals) from that time interval. A succession of faunal assemblages, corresponding to the Early Campanian, the Late Campanian/Early Maastrichtian and the Late Maastrichtian, can now be recognised, with a marked change in the dinosaur fauna during the Maastrichtian, but no clear evidence of decline during the last million years of the Cretaceous. The biogeographical complexity of the Late Cretaceous vertebrate assemblages from southwestern Europe is underlined. Ces dernières années, des prospections et des fouilles systématiques dans le Campanien et leMaastrichtien continentaux du Sud de la France, de la Provence à l'Est à la vallée de la Garonne à l'Ouest, ont considérablement augmenté notre connaissance des vertébrés continentaux (poissons, amphibiens, tortues, squamates, crocodiliens, ptérosaures, dinosaures, oiseaux et mammifères) de cette période. Une succession d'assemblages fauniques, correspondant au Campanien inférieur, au Campanien supérieur/Maastrichtien inférieur et au Maastrichtien supérieur, peut désormais être reconnue, avec un changement marqué dans la faune dinosaurienne au cours du Maastrichtien, mais pas de preuve claire d'un déclin pendant les derniers millions d'années du Crétacé. La complexité biogéographique des assemblages de vertébrés du Crétacé supérieur du Sud-Ouest de l'Europe est soulignée.

Late Cretaceous and Paleocene Pan-American Interchanges of Continental Vertebrates

Late Cretaceous and Paleocene Pan-American Interchanges of Continental Vertebrates

First record of the family Dromaeosauridae (Dinosauria: Theropoda) in the Cretaceous of Gondwana (Wadi Milk Formation, northern Sudan)

The Cenomanian Wadi Milk Formation in Sudan yielded a rich continental vertebrate fauna. Apart from big theropod fragments, some disarticulated elements of a pes and a tooth indicate the presence of a dromaeosaurid theropod in the Late Cretaceous of Sudan. This is the first record of this theropod family from Gondwanian continents.

Testing the time axis of phylogenies

Fossils are not perfect materials for phylogenetic analysis because of problems of missing characters and missing taxa. However, fossils have three major advantages: (1) they give the only direct evidence of the order of acquisition of characters, (2) they frequently present character combinations not found in modern forms, and (3) they may allow the coding of characters that have been overwritten by subsequent evolution within a clade. There are three independent sources of evidence about sequences of historical events in evolution - morphological, molecular and stratigraphic - and these may be mutually cross- tested. Tests of the quality of the fossil record against morphological cladistic data show that (1) age and clade data on branching sequences generally agree, (2) knowledge of the fossil record has improved by 5% over the past 26 years of research, and (3) the fossil record of continental vertebrates is as good as that of (marine) echinoderms. Hence, systematists and evolutionary biologists may use fossil data with confidence in phylogeny reconstruction and to calibrate the time axis of phylogenies.

Testing the marine and continental fossil records

The fossil record of continental vertebrates is as good as that of echinoderms at the family level, as shown by tests of the match of cladistic and stratigraphic data and of relative completeness. If echinoderms and vertebrates are typical of their environments, the continental fossil record is not worse than the marine, despite the fact that, at a local level, fossils are usually more abundant in marine sequences than in continental successions. The explanation of this paradox may be that vertebrates have attracted more intensive study than echinoderms, and thus the level of knowledge of their fossil record is some decades ahead of that of echinoderms. This finding validates the use of different kinds of fossil data in broad-scale phylogenetic studies.

Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland

A diverse assemblage of fossil vertebrates has been discovered in the Fleming Fjord Formation (Malmros Klint and Ørsted Dal Members) in East Greenland between latitudes 71°15'N and 71°50'N. The fauna includes several species of mammals as well as prosauropod (Plateosaurus) and theropod dinosaurs, turtles (cf. Proganochelys), pterosaurs, aetosaurs (Aetosaurus ferratus, Paratypothorax andressi), labyrinthodont amphibians (Gerrothorax, Cyclotosaurus and possibly other taxa) and fishes (including sharks, actinopterygians, coelacanths and lungfish). The association of the genera Aetosaurus, Plateosaurus, Proganochelys, Cyclotosaurus and Gerrothorax is shared with well known European Norian faunas, and confirms the paleogeographic proximity of Greenland and Europe during Late Triassic time. On this evidence, the Ørsted Dal Member may be estimated to be at least as old as mid-Norian, but a comparable age estimate for the underlying Malmros Klint Member cannot be made on the basis of the fauna as presently known. The Malmros Klint Member is characterized by composite cyclicity with four orders of cycles involving silt-rich, ephemeral lake or playa-mudflat systems, loess beds, wave-reworked sand flats, flat pebble conglomerates and paleosols. The rhythmicity and thickness ratios of the beds are evidence that depositional conditions were controlled by Milankovitch cycles, with climatic conditions varying from humid, to dry with seasonal rainfall, to arid. Cyclical sedimentary conditions and climatic fluctuations appear to have continued during the subsequent deposition of the overlying Ørsted Dal Member.

A psittacosaurid dinosaur from the Cretaceous of Thailand and its implications for the palaeogeographical history of Asia

ABSTRACTPrimitive ceratopian dinosaurs of the family Psittacosauridae were hitherto known only from central and northern Asia, from northern China to Mongolia and Siberia. This paper reports the discovery of psittacosaurid jaws in Early Cretaceous rocks of the Khorat Plateau in north‐eastern Thailand. These fossils are clearly referrable to the genus Psittacosaurus Osborn and may represent a new species. They constitute a significant new element of the hitherto poorly known Cretaceous continental vertebrate fauna of South‐East Asia, suggesting that it was basically similar to that of northern and central Asia. This in turn confirms that, contrary to some recent palaeogeographical reconstructions, by Early Cretaceous times the Indochina block, on which the Thai psittacosaurids have been found, had become part of mainland Asia.

Terrestrial tetrapods in Cretaceous Antarctica

Abstract The fossil record of continental vertebrates from Antarctica is practically nonexistent, hence the composition of the supposed Mesozoic terrestrial vertebrate fauna must be inferred indirectly. This may be done using the reconstructed positions of the continents during the Mesozoic. These positions suggest the presence in Antarctica of primitive sauropods, large theropods, hypsilophodontian and iguanodontid ornithopods, ankylosaurs, pterosaurs, crocodilians, lungfish and possibly birds. In the absence of evidence to the contrary, monotremes are considered endemic Australian forms during the Cretaceous. The discovery of hypsilophodontian material in New Zealand corroborates the inference of Antarctic hypsilophodontians from their occurrence in Australia. The existence in the Australian Early Cretaceous of relict taxa and taxa that seem unusual compared to their overseas relatives suggests that the south polar tetrapod fauna was characterized by singular forms.

Stratigraphy of the Cretaceous-Tertiary and Paleocene-Eocene Transition Rocks of Big Bend National Park, Texas: A Discussion

graphic succession of continental vertebrate faunas spanning Late Cretaceous through early Tertiary time-the southernmost such sequence in North America. The Tornillo Group is also important in recording the development of the Laramide Orogeny in West Texas. The work of Schiebout et al. (1987) is an important addition to knowledge of this critical time interval in North America; however, they propose changes in formation nomenclature that in my view are unnecessary. Schiebout et al. (1987) propose to reduce the formations of the Tornillo Group (Javelina, Black Peaks, and Hannold Hill formations) to member rank, and to remove the lower part of the Canoe Formation (Big Yellow Sandstone) from the Big Bend Park Group and include it as a member of the reinstated Tornillo formation. They also revise the boundary between the Javelina and Aguja formations. The proposed revisions are, in my view, unjustified and unsupported, and should not be adopted. The following comments are offered in support of the continued use of the nomenclature established by Maxwell et al. (1967).

Late Maastrichtian paleoenvironments and dinosaur biogeography in the western interior of North America

During Late Maastrichtian time, three major sedimentary depositional provinces existed in continental environments of the western interior region of North America. The sediments accumulated within these provinces are herein termed the piedmont, alluvial plain, and coastal lowland lithosomes. These sedimentary lithosomes correspond to broad paleoenvironmental and paleophysiographic provinces that resulted from the westward shift of the Pacific coast, the bisection and retreat of the interior epeiric sea, and the development of an intermontane basin system during Maastrichtian time. These dramatic physiographic changes created environments markedly different from those that had prevailed during most of the Late Cretaceous, when western North America consisted of a narrow peninsula flanked on the east by a remarkably stable and monotonous coastal plain. In conjunction with these physiographic and environmental changes, three diverse dinosaur-dominated continental vertebrate faunas arose, herein termed the Leptoceratops, Triceratops, and Alamosaurus faunas. Each was peculiar to a sedimentary/environmental province and among them there was little interchange. The separation of these faunas indicates that the dinosaur-dominated communities had adapted to changing or “deteriorating” environmental conditions at the close of Cretaceous time. The Alamosaurus fauna characterized markedly seasonal, semi-arid, environments of the intermontane basins south of about 35°N latitude. The Triceratops fauna inhabited humid coastal floodplains and swamps bordering the retreating northern embayment of the epeiric sea, north of latitude 35°N. The Leptoceratops fauna inhabited cool piedmont environments flanking the mountainous Cordilleran Overthrust Belt north of 35°N latitude. Recognition of this biogeographic zonation indicates that the Triceratops biozone is only of local utility, and that the biostratigraphy of Upper Cretaceous continental deposits in North America must reflect the provincialism now recognized. Moreover, the evident adaptability of dinosaur faunas to varied and changing environmental conditions suggests that climatic change alone may not have been responsible for their demise.

The problem of correlations between South Europe and North Africa during the pleistocene

The most complete stratigraphical sequence, allowing to draw in North Africa a relative chronology of the Pleistocene, was established in Morocco. It is based on eustatic transgressions and regressions of the Atlantic Ocean which left various deposits alternating with continental formations. They yielded both fossil faunas and prehistoric industries. Correlations with the European or African coasts of the Mediterranean Sea are difficult because of the Quaternary tectonic activity in this area. Today the best data are provided by the Iberian Peninsula, specially the Portuguese coast, where the eustatic variations of the sea level are similar to those of the Moroccan coast. Numerous difficulties appear for the comparison of the various faunas from south Europe and from North Africa. The invertebrate paleontology shows a constantly different environment between the Mediterranean and Atlantic littorals. For example Strombus bubonius is unknown on the Moroccan Atlantic Coast. The “Nordic fauna”, very useful in the Moroccan raised beaches, is useless in Portugal where it is still presently living. Similar difficulties arise concerning the paleontology of continental vertebrates. Since the Villafranchian, the same genera are found north and south of the Mediterranean Sea, but not the same species. Furthermore, contrarily to what occurred in Europe, there was no faunal-break in Africa during the Glacial periods. As for prehistory, we need more information on the oldest European industries. In Portugal there are numerous pebble-tools but no assemblage was found in situ in Lower Pleistocene formations, and up to the present no pre-Acheulian complex is proved to exist, contrarily to what is ascertained in North Africa. For Acheulian industries, comparisons are easier; Early and Middle Acheulian have similar evolutions. Only with evolved Acheulian significant differences appear.

Near-shore marine and continental sediments of the Sirte basin, Libya

At the end of the Cretaceous period the Sirte basin developed in North Africa between the Tethyan foredeep and the Sahara Shield. In-filling of the basin throughout the Tertiary era resulted in the deposition of a thick sequence of clastic rocks and carbonates with minor evaporites. The Sirte basin contains large quantities of oil and gas. This paper describes mixed carbonate and clastic Miocene shoreline deposits of a type which prevailed during much of the history of the Sirte basin. These rocks have been studied in the field using sedimentological logging techniques. Forty-seven detailed sections have been recorded totalling some 3000 m of sediment over an area of about 1500 sq km. Some 26000 field observations have been made. These have been used to interpret the depositional environments of these rocks by comparison with studies of recent sediments. Five major facies have been recognized; each has been given a type section and is defined by five parameters, viz: geometry, lithology, sedimentary structures, palaeontology and palaeocurrent pattern. Four of these facies trend parallel to the shore of the Sirte basin. They are locally cross-cut by the fifth. In the north bioclastic limestones were deposited by the shoreward migration of offshore bars and barrier beaches. These interfinger southwards with laminated lagoonal shales with oyster banks. The shales in turn pass shorewards into interlaminated fine sands, silts and shales with abundant bioturbation and micro-cross-lamination. These beds are cut by channels of inclined laminated sand and shale. This third facies is interpreted as inter-tidal, the channels originating as creeks which drained the mud flats. The most southerly (landward) of these four facies consists of crossbedded sands and shales, lignites, rootlet beds, with a spectacular fauna of continental vertebrates. These beds are thought to be the deposits of a fluviatile coastal plain. The four facies belts just described are replaced at two places by n–s trending calcareous sandstone shoe-string complexes interpreted as estuarine channels. Palaeocurrent analysis shows that carbonate sediment, generated in the offshore zone, was transported up-slope towards the land, while clastic sediment was carried seawards from the Sahara Shield. Bipolar palaeocurrents in the calcareous sandstone channels indicate mixing of these two sediment types within the estuarine environment. This Miocene shoreline was similar to the present-day coast of south west Texas, though in this analogue the barriers are made of non-carbonate sediment. The Miocene limestones are broadly comparable to the present-day barrier carbonates of the Trucial coast and have certain points of similarity with recent carbonate sands of the Bahamas.

Note sur la decouverte d'un gisement de vertebres continentaux dans le Trias du Haut-Atlas occidental

Abstract Remains of continental Triassic vertebrates have been found north of Tizi Maachou in the High Atlas range, Morocco. The stratigraphy of the area is outlined, and the identified fossils briefly described. Stegocephalian amphibians, theropod reptiles, and a therapsid are represented in the fauna. A position high in the Triassic, probably Keuper, is indicated for the locality.