Jean-Loup Welcomme

Himalayan Forelands: palaeontological evidence for Oligocene detrital deposits in the Bugti Hills (Balochistan, Pakistan)

In the southwestern Sulaiman geological province (Balochistan, Pakistan), terrestrial detri- tal facies from the Bugti Hills region have yielded the richest Tertiary vertebrate faunas to be found in Asia thus far. New fossils from five successive and distinct bone beds bridge the supposed Oligocene sedimentary hiatus within the Sulaiman geological province; the lowermost continental levels of the previously described Miocene Chitarwata Formation, known as the Bugti Member, are Oligocene in age in the Bugti area. Neither a mixture of heterochronic faunal elements nor endemism of any fauna is evident in this area. Additional microfaunal material from the Bugti Member constrains an Oligocene age for the lower Chitarwata Formation in Zinda Pir (northeast of the Bugti Hills). This Oligocene transition between the marine Kirthar (Eocene) and continental Siwalik (Miocene) deposits consists of a regressive fluvio-deltaic system occupying a vast floodplain. It represents an early-stage molasse in the palaeo-Indus Basin which drained western orogenic highlands resulting from the colli- sion between the Indian and Eurasian plates.

FIRST RECORD OF PALEOGENE ELEPHANTOIDEA (MAMMALIA, PROBOSCIDEA) FROM THE BUGTI HILLS OF PAKISTAN

PIERRE-OLIVIER ANTOINE1, JEAN-LOUP WELCOMME1, LAURENT MARIVAUXI, IBRAHIM BALOCH2, MOULOUD BENAMMI3, and PASCAL TASSY4, 1Laboratoire de Paldontologie, CC064, Universit6 Montpellier 2, F-34095 Montpellier, France, poa@lmtg.ups-tlse.fr; 2Geology Department, University of Balochistan, Sariab Road, Quetta, Pakistan; 3Laboratorio de Paleomagnetismo, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF, Mexico; 4Laboratoire de Paldontologie, CNRS UMR 8569, Museum national dHistoire naturelle, 8 rue Buffon, F75005 Paris France.

NEW DIATOMYID AND BALUCHIMYINE RODENTS FROM THE OLIGOCENE OF PAKISTAN (BUGTI HILLS, BALOCHISTAN): SYSTEMATIC AND PALEOBIOGEOGRAPHIC IMPLICATIONS

Abstract The rodents (Baluchimyinae and Fallomus) from the Bugti, Sulaiman, and Ladakh deposits (Indian subcontinent) were originally considered a distinct early Miocene group that arose via local evolution from the Eocene Chapattimyidae in the Indo-Pakistan province. The Bugti Member, the lowermost continental beds of the previously ascribed Miocene Chitarwata Formation, is now considered to be Oligocene. A new continental vertebrate locality from the basal part of the Bugti Member (Paali nala C2) has yielded an important early Oligocene small mammal fauna including a well-diversified rodent assemblage that allows revision of the age attributed to the classic Bugti rodent fauna. Additional specimens (mainly isolated teeth) allow a systematic review of Fallomus (Diatomyidae) and Hodsahibia (“Baluchimyinae”), and two new species are described for each genus (F. ginsburgi, sp. nov.; F. quraishyi, sp. nov.; H. gracilis, sp. nov.; and H. beamshaiensis, sp. nov.). The presence of several higher rodent taxa at Paali nala C2 suggest that there was not an extended period of mid-Tertiary faunal isolation on the Indian subcontinent, nor an abrupt turnover between Chitarwata and Lower Siwalik rodent faunas. “Baluchimyines,” here considered Hystricognathi incertae sedis, are part of a diverse assemblage of hystricognathous rodents in South Asia at the end of the Paleogene. A close phylogenetic relationship between “baluchimyines” and earliest Asian hystricid rodents is plausible.

Mise en évidence de l'Oligocène sur le territoire des Bugti (Balouchistan, Pakistan)

Resume Plusieurs especes de mammiferes fossiles appartenant a des genres connus uniquement dans lOligocene dEurope ont ete signalees dans le Miocene des Bugtis au Balouchistan. Au cours des recoltes que nous avons effectuees recemment dans le synclinal de Dera Bugti, nous navons pu recolter aucun specimen se rapportant a ces genres. De plus, lexamen de chaque piece autrefois recoltee montre, soit quelles ont ete mal determinees, soit quelles proviennent dune longue et etroite bande de terrain situee sur le flanc nord du synclinal plus meridional de Gandoi, et jusque-la confondue avec le Miocene.

New tropical carcharhinids (chondrichthyes, Carcharhiniformes) from the late Eocene-early Oligocene of Balochistan, Pakistan: Paleoenvironmental and paleogeographic implications

New selachians (sharks and rays) have been collected from several late Eocene and early Oligocene marine localities in the Bugti Hills (Balochistan, Pakistan). Two new species of Requiem sharks (close to the Recent ?Bull shark?) are described : Carcharhinus balochensis and Carcharhinus perseus. The rest of the fauna is notable for the strong representation of Carcharhiniformes. These selachian faunas represent a unique tropical association for the Oligocene period and one of the first modern tropical selachian faunas, with modern taxa such as the two new species of ?Bull sharks?, Negaprion sp. and one of the first occurrences of Sphyrna sp. Moreover, these faunas permit paleoenvironmental interpretation of adjacent land masses. The relatively modern aspect of these faunas, compared with other contemporaneous and younger selachian associations from Atlantic and Mediterranean seas, suggests biogeographic isolation of selachian communities living in eastern and western parts of the Tethys before its final closure during the early-middle Miocene.

Première découverte de Cricetidae (Rodentia, Mammalia) oligocènes dans le synclinal sud de Gandoï (Bugti Hills, Balouchistan, Pakistan)

The preliminary analysis of a new continental vertebrate locality from the basal part of the Bugti Member (Baluchistan) focuses on the Cricetidae. From dental remains, two new species are described here, and related to genera Pseudocricetodon and Atavocricetodon, well known in the Early Oligocene from Europe. Compared to the European and Chinese Late Eocene specimen, their evolutionary stage suggests the Bugti locality to be Early Oligocene in age. These species are the first but also the oldest Paleogene record of the family on the Indian subcontinent and represent the originating ancestor group of the European cricetids.

Listriodon guptai Pilgrim, 1926 (Mammalia, Suidae) from the early Miocene of the Bugti Hills, Balochistan, Pakistan: new insights into early Listriodontinae evolution and biogeography

New dental remains of listriodont suids are described from the lower member of the early to middle Miocene Vihowa Formation of the Bugti Hills, Pakistan. The material is homogeneous in terms of morphology and dimensions and referred as a whole to Listriodon guptai Pilgrim, 1926. This species is also mentioned in coeval deposits of the Zinda Pir Dome, Pakistan, dating back to ca. 19xa0Ma. The early occurrence of an advanced listriodont in Pakistan constrains the age of acquisition of several characters correlated to lophodonty within Listriodontini, and raises major questions about the early history of the Old World Listriodontinae. Strong morphological similarity between Listriodon guptai and the African species Listriodon akatikubas found in the late early Miocene of Maboko (Kenya, ca. 16.5xa0Ma) suggests that this latter is most probably a migrant originating from Asia.

New remains of the enigmatic cetartiodactyl Bugtitherium grandincisivum Pilgrim, 1908, from the upper Oligocene of the Bugti Hills (Balochistan, Pakistan)

Newly discovered fossil material of the enigmatic cetartiodactyl Bugtitherium grandincisivum from the upper Oligocene of the Bugti Member of the Chitarwata Formation in the Bugti Hills (Balochistan, Pakistan) is reported. These new specimens consist of two fragmentary muzzles (one preserving the first incisors and belonging to a juvenile) and a fragmentary right mandible with m3. The morphologies of the anterior dentition and m3 provided by these new specimens confirm the validity of the genus Bugtitherium and advocate probable anthracotheriid affinity for the genus rather than entelodontid or suoid affinities, but do not definitively close the debate about Bugtitherium’s familial affinities within Cetartiodactyla. Although still poorly documented, this large-sized anthracotheriid-like cetartiodactyl is a possible key form for understanding the early evolution of hippos, and, in turn, the ancestry of whales, because of both its morphological similarities with hippos and primitive Paleogene whales and its Tethysian distribution.