Herbert Thomas

A consideration of some major topics concerning Old WorldMiocene Mammalian chronology, migrations and paleogeography

Abstract The authors of this note met to discuss the chronology of certain Miocene biologic events and their implications concerning palaeogeographic reconstructions. Two topics in particular were examined. The first was that the collision of the Afro-Arabian Plate into mainland Asia appears to have had a gradual effect on the mammalian and marine faunas. The marine evidence suggests a progressive diminution in exchanges between the Mediterranean Sea and the Indian Ocean from the Chattian/Aquitanian boundary onwards (Adams et alii 1983) whereas the continental mammalian faunas do not indicate the occurrence of faunal interchanges prior to the Burdigalian. The period between 18 and 20 Ma seems to be the key moment for the establishment of intercontinental pathways permitting faunal exchanges between the two land masses. The second subject examined concerned the « Hipparion datum. Analysis of available geochronological evidence and biostratigraphical correlations do not confirm the date of 12.5 Ma attributed to the earliest known Mediterranean Hipparions. On the contrary, it seems that the radiometric dates obtained from tuffs at Howenegg (Germany) and Bou Hanifia (Algeria) on which this early date was founded, are not closely associated with the fossils they purport to date. New radiometric dates allied with magneto- and biostratigraphy allow us to suggest an age about 11.5 Ma to the earliest records of Hipparion in Europe and North Africa.

First Pleistocene faunas from the Arabian Peninsula: An Nafud desert, Saudi Arabia*

Three Pleistocene vertebrate localities in lacustrine deposits which accumulated in interdune depressions were discovered in the south-western part of the An Nafud sand sea (northern Saudi Arabia). Although the fossil vertebrate fauna is restricted in diversity, its composition and stage of evolution suggest an Early Pleistocene age in contrast with the recent Pleistocene or Holocene lake beds occurring in several other interdune depressions in central and southern An Nafud. The Nafud fauna has clear African affinities whereas faunas from the Levant, dating from the Middle Pleistocene onwards, contain typically European elements.

The discovery ofMoeripithecus markgrafi Schlosser (Propliopithecidae, Anthropoidea, Primates), in the Ashawq Formation (Early Oligocene of Dhofar Province, Sultanate of Oman)

Abstract Several isolated teeth, a fragment of mandible with P 3 -M 3 , and four associated upper cheekteeth (P 3 -M 2 ) of a large propliopithecid were recovered from the early Oligocene locality of Taqah (Ashawq Formation, Sultanate of Oman). All these teeth, as well as the paratype of Propliopithecus ankeli , are here attributed to the Fayum anthropoid Moeripithecus markgrafi Schlosser. This taxon was until recently known only from the holotype, a fragment of mandible with M 1 -M 2 . Considering the striking differences in morphology between M. markgrafi and P. haeckeli (type species of the genus Propliopithecus ), confirmed and extended by the new material from Oman, we here conclude that Schlosser was justified in recognizing the generic distinction between Moeripithecus and Propliopithecus .

The enigmatic new indochinese bovid, Pseudonovibos spiralis : an extraordinary forgery

In 1993, the discovery of several pairs of lyre-shaped horns with corrugations was recorded in Vietnam and regarded as evidence for a new, large bovid, later referred to as Pseudonovibos spiralis Peter & Feiler, 1994. Despite numerous field investigations made since 1994 in Vietnam and Cambodia, no new anatomical evidence has ever been found, except for two frontlets with their horn cores and horn sheaths. A new investigation has been carried out on six frontlets and based on a histological analysis of the keratin. It shows that the horns of P. spiralis are merely a skillful forgery made by carving and distorting ordinary cow horns. The horns of Pseudonovibos spiralis were, in some cases, positioned back onto the corresponding horn cores of domestic cow frontlets. The name Pseudonovibos spiralis is thus a junior synonym of Bos taurus, yet it remains valid and available.

Fossil wood of Sindora (Leguminosae, Caesalpiniaceae) from the Oligo-Miocene of Saudi Arabia: paleobiogeographical considerations

Abstract Fossil wood, collected near the western coast of Saudi Arabia, originates either from the Raghama Formation (Miocene), or from the Dhaylan Formation (Oligocene). Its structure designates this wood as a representative of Recent tropical rain forest Sindora trees and the fossil species Hopeoxylon indicum. The largely disjoined distribution of Recent Sindora is in contrast to the continuity of localities yielding fossils closely related to Sindora. A discussion is held on the dispersion direction of Sindora and geographic and climatic modifications in the Tertiary: Early Miocene land connection; climatic drying at the beginning of the Middle Miocene in the west; and later on in India and Pakistan.

Late Paleocene to Early Eocene marine vertebrates from the Uppermost Aruma Formation (northern Saudi Arabia): implications for the K-T transition

A new assemblage of marine vertebrates from northern Saudi Arabia, east of the Nafud, leads us to reconsider the age of the top unit of the Aruma Formation, the Lina Member, hitherto referred to the Maastrichtian. This assemblage contains the remains of a dozen selachian and actinopterygian fishes, as well as those of a giant sea turtle representing a new dermochelyid taxon. It suggests a Late Paleocene to Early Eocene age for this unit. This new dating and a revision of the stratigraphic position of the Lina Member demonstrate the existence, on a regional scale, of an important hiatus at the K-T boundary.

A new dermochelyid turtle from the Late Paleocene-Early Eocene of Saudi Arabia

Abstract A new dermochelyid sea turtle, Arabemys crassiscutata n. gen, n. sp., is described on the basis of epithecal shell mosaic ossicles from the Late Paleocene—Early Eocene of Saudi Arabia. This is the oldest and the most primitive known representative of the dermochelyids having an epithecal shell mosaic.

Discovery of a Stegodon-Ailuropoda assemblage in a cave of northern Thailand (Ban Fa Suai, Chiang Dao)

The Cave of the Monk from the village of Ban Fa Suai is an original site discovered by the Thai French Palaeosurvey during one of its field campaign looking for the remains of the first humans in northern Thailand. Preliminary data from geological, palaeontological and technolithic domains of this site are presented in this paper. Focusing on taphonomy it is an opportunity to describe evidence of a Stegodon-Ailuropoda fauna in a karstic context and the occurrence of Hoabinhian stone tools assemblages in a stacked overlain fossil gallery. The Cave of the Monk is a typical sample for several areas of South-East Asia. Sixteen families, 25 genus and 38 species of Mammals have been identified among the dental remains collected by procupines. The technological analysis shows that the lithic tools are similar to those originating from Indonesia.