The Registration of the Mid-Paleocene Biotic Event (MPBE) in Tunisia

In Tunisia, the Paleocene biomarkers are identified within the El Haria Formation shales. The Selandian is absent in most of the Paleocene outcrops and the Thanetian is unconformable to different stages of the Cretaceous. In the middle of Selandian, with the beginning of the Globanomalina pseudomenardii (P4) zone, we note that the assemblage of planktonic foraminifera becomes very poorly preserved and much less abundant than at the base. It is represented by rare species and there has been a start of the microfauna dissolution tests and an enrichment in iron oxides, silica, and gypsum crystals. The dissolution process is increasing more and more and a drop in the content of carbonates is clearly recorded at the top of Selandian. However, we note that some small benthic foraminifera belonging to the genera Lenticulina and Anomalina escape the dissolution and very few planktonic foraminifera belonging to the genera Subbotina are preserved. This dramatic and abnormal dissolution extends over a considerable thickness. These features could be an expression of the mid-Paleocene biotic event (MPBE), registered for the first time in Tunisia. This intense dissolution is caused probably by the change in the solubility of carbonates, which may be related to the changes in the deep-water circulation or to the change in the productivity of the surface waters.

Some Eocene Cerithioids (Gastropoda, Mollusca) from Kutch, Western India, and Their Bearing on Palaeobiogeography of the Indian Subcontinent

The cerithioids are a diverse group of gastropods found globally as fossil and living animals during the Cenozoic Era. Their systematics is riddled with problems stemming from large morphological variability, homoplasy, and wide geographical distribution. Six cerithioid species are described here from the lower Middle Eocene of Kutch, Gujarat, western India. All but two are new species. They are Palmerella kutchensis, Tenagodus? sowerbyi, Potamides archiaci, and Cerithium harudiensis. The rest are new records from Kutch and were known only from Pakistan. A palaeobiogeographical review based on major published records of benthic molluscs from Pakistan reveals strong endemism. The cerithioid faunas from different parts of Pakistan and this report from Kutch also show strong endemism and often quite localized development. It is argued here that unhindered faunal mixing was not possible in this province since these newly evolved basins were restricted in nature in their Lower Cenozoic history.

Migration Routes of the Aptian to Turonian Ostracod Assemblages from North Africa and the Middle East

Quantitative paleobiogeography is a powerful tool for detecting the migration routes of microfossils. This is factual and applicable when we select appropriate analyses for proper problems in the following manner. The quantitative study of 43 selected ostracod species (total of 136 species) from 11 countries of North Africa and the Middle East led to the detection of two migration routes in the late Early to early Late Cretaceous times. The first route of migration was from east to west during the intervals of Aptian-Albian to Cenomanian. While in the Turonian time, reduced oxygen conditions prevailed and minimized the east-west migration. The second route was from north to south for the duration of Aptian-Albian to Cenomanian. On the other hand, four ostracod biofacies, each with its distinctive environmental conditions, have been identified in the studied countries ranging in age from Aptian to Turonian.

Skeleton of the Fossil Shark Isurus denticulatus from the Turonian (Late Cretaceous) of Germany—Ecological Coevolution with Prey of Mackerel Sharks

An Isurus denticulatus (Glickman, 1957) shark skeleton from the late Turonian (Late Cretaceous) of Germany is described within a diverse upwelling influenced fish fauna of northern Germany, Europe. It was found in the turbiditic marly limestones at the submarine Northwestphalian Lippe Swell in the southern Proto-North Sea Basin. Compared to modern mackerel shark Isurus oxyrinchus Rafinesque, 1809, including cranial denticles, this allows a revision of the younger synonym “Cretoxyrhina Glickman, 1964”. Within the Cretaceous Isurus, a loss of the lateral tooth cusps and nutritive clefts of the roots (considered as plesiomorphic character of the Lamnidae) took place from the Albian (Early Cretaceous) to the Campanian (Late Cretaceous). The tooth morphology changed during the Albian-Turonian from a tearing (I. denticulatus) to a cutting (I. mantelli) type (Coniacian-Campanian). The complete lateral cusplet and symphyseal teeth reduction in Isurus at the end of the Cretaceous seem to be a result of the coevolutionary changing feeding habits of a worldwide expanding shark. In a second evolutionary adaptation, parallel to the new radiation of marine mammals (Paleocene/early Eocene), from Isurus, the white shark ancestors (Carcharodon) seem to originate. In another radiation from Isurus, coevolving with appearance of dolphins and further marine mammal evolution within the Middle Miocene, a second time Isurus developed serrated teeth (I. escheri).

Palaeopopulations of Late Pleistocene Top Predators in Europe: Ice Age Spotted Hyenas and Steppe Lions in Battle and Competition about Prey

Late Pleistocene spotted hyena Crocuta crocuta spelaea (Goldfuss, 1823) and steppe lion Panthera leo spelaea (Goldfuss, 1810) were top predators in Central Europe. The fossil record (2.303 hyena/1.373 lion bones = ratio 3/1) from 106 cave and open air sites demonstrates comparable associations to modern African hyenas/lions resulting in competition about prey and territory. Cannibalism within extinct spotted hyenas is well documented, including two individual skeletons. Those hyenas produced bone accumulations at dens. Feeding specializations on different megamammal groups are demonstrated for Late Pleistocene hyenas whose prey partly overlaps (e.g., cave bears) with those of lions and wolves. At most fossil sites, 1–3% of the lion remains indicate scavenging of lions by hyenas. The larger Late Pleistocene felids focussed on cervids (reindeers specialization during the high glacial = LGM), on bovids (steppe bison/aurochs), and possibly on saiga antelope and on the cave bear, hunting deep in caves during their hibernations and targeting cubs. The cave bear feeding was the target of all three top predators (lions, hyenas, and wolves) in the Late Pleistocene boreal forests which caused deathly conflicts in caves between them, especially with lions/hyenas and herbivorous cave bears that have no modern analogue.

Palaeobiology of Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden

Leptaenine brachiopods are common and widespread on Gotland. Lepidoleptaena poulseni and Leptaena rhomboidalis retained a functional apical pedicle throughout ontogeny, and both had strong adductor muscles and robust ornamentation, allowing them to occupy shallow water and high energy environments. A pedicle-shortening muscle is present within the pedicle tube of Leptaena rhomboidalis. Leptaena sperion, L. depressa visbyensis, and L. depressa lata inhabited low energy environments, retaining very slender pedicles. L. depressa depressa and L. parvorugata atrophied the pedicle early and then lived ambitopically in deeper water. The presence or absence of the apical pedicle strongly influenced the cardinal process morphology. Leptaenine shells had a small gape. The lophophore was simple, similar to productids and Leptaenoidea. In closed valves, the inner epithelium of leptaenine trails remained exposed to the sea. This was probably important in gas exchange. The life position of pedically attached species was with the disc vertical. Some ambitopic specimens may have retained a similar attitude. Shells of L. depressa depressa and Lepidoleptaena poulseni commonly are encrusted by epibionts, apparently without problems for larger shells. Small shells are shown to have been killed by bryozoan epizoans. Repaired shell damage is rare on the disc but is common along the commisure.

Planktonic Foraminiferal Biostratigraphy and Correlation Across the Cretaceous-Paleogene Transition at the Tethyan and the Atlantic Realms

Based on high-resolution planktonic foraminiferal biostratigraphical analysis at El Kef stratotype section (GSSP for the K/Pg boundary), Ellès section in Tunisia, and Agost and Caravaca sections in Spain (Tethyan realm), we attempt to compare biozones and subzones with those of the Bidart section (SW France) (Atlantic realm). The Abathomphalus mayaroensis zone of the upper Maastrichtian corresponds to the taxon range interval of the nominate species. We have identified the Plummerita hantkeninoides subzone. This species is present and associated with Pseudoguembelina hariaensis at the Tethyan realm. However, this species is absent at the middle latitude of the Atlantic realm (Bidart section, SW France). The Pseudoguembelina hariaensis species had larger paleogeographic spread, as it was present in both the Tethys and the Atlantic paleoceans. It is more relevant to be considered as the biomarker of a nominate uppermost Maastrichtian subzone instead of Plummerita hantkeninoides. The Danian stage is characterized by the Gt. cretacea zone, Pv. eugubina zone, and the Parasubbotina pseudobulloides zone. The deposition thickness of the zones and subzones at El Kef stratotype section and Ellès section is more expanded than at Agost and Caravaca sections (Spain) and Bidart section (France). They would be controlled by the sedimentary basin morphology.

Revision of the Messinian-Early Zanclean Sediments from ODP Hole 953C (Canary Island Archipelago, North-Eastern Atlantic): Biostratigraphy, Cyclostratigraphy, and Astronomical Tuning

A quantitative study was performed on calcareous plankton of the Messinian-early Zanclean succession recovered at ODP Leg 157 Hole 953C (Canary Island Archipelago, North-Eastern Atlantic). This revision allowed to recognize some events typically recorded in the Mediterranean region, highlighting affinities between the Mediterranean and North Atlantic Ocean, in the considered time interval. The presence of such events in an open-ocean succession provides the possibility to substantially improve the biostratigraphic resolution and supplies useful correlation tools between the Mediterranean and oceanic areas. Moreover, to unravel cyclical patterns of deposition and given that the investigated succession shows no evident lithological pattern, cyclostratigraphic analyses have been based on abundance fluctuations of Globigerinoides-Orbulina group, neogloboquadrinids, and warm-water versus cool-water species ratio. As a result, forty-three precession-controlled cycles have been recognized spanning from 6.457 Ma to 4.799 Ma.