NEW PAKISAURUS (PAKISAURIDAE, TITANOSAURIA, SAUROPODA) REMAINS, AND CRETACEOUS TERTIARY (K-T) BOUNDARY FROM PAKISTAN

Abstract

Pakisaurus remains has been found from the latest Cretaceous Vitakri Formation (previous upper member of Pab Formation) in Kinwa, Bor, Top Kinwa, Shalghara, Sangiali, Alam Kali Kakor (north), Zubra, Darwaza, Grut, Dolvahi east, and some other localities of Sulaiman Basin, Pakistan. These fossils provide head to tail and back to foot morphology. Multipurpose tail special with trispinous distalmost caudal centrum of Pakisaurus of Pakisauridae and some or all genera of Pakisauridae and Balochisauridae found from Pakistan provide a new look of titanosaurs. The skull discoveries of Pakisaurus (Marisaurus and Balochisaurus) add the skull diversity of titanosaurs from Pakistan. The Pakisaurus skull represents widely spaced teeth, and fibrous laminations on external surface of jaw and large open internal cells in the interior jaw rami. Due to dearth of cranial data and lack of common associated elements in titanosaurs has left even the most basic skeletal morphology of the clade controversial and has precluded detailed study of its higher and lower level phylogeny, but now Pakistan has this advantage which produced associated cranial, axial and appendicular elements of Pakisaurus (Marisaurus and Balochisaurus). The Pakisaurus, Marisaurus, Balochisaurus, Rapetosaurus, some Argentinean and Mongolian forms have great potential to resolve paleobiogeography, lower and higher level phylogeny of titanosaurs. Cretaceous Tertiary (K-T) boundary is well exposed on the western continental margin of IndoPakistan plate like Kirthar and Sulaiman basins, and on the northwestern margin like Kohat and Potwar basins. The K-T boundary sharing formations which are well exposed in the Kirthar and Sulaiman basins are the Late Cretaceous Pab/Vitakri Formation, and Paleocene Sangiali/Khadro Formation, however near to Axial belt the Cretaceous Parh and Mughal Kot formations and Paleocene Dungan Formation. Geological formations below and above the K-T boundary, in the western Salt Range are Chichali and Hangu; in the Surghar Range are Lumshiwal and Hangu; and in the Kohat and Kala Chitta-Hazara areas are Kawagarh and Hangu formations. Cretaceous Chichali/Lumshiwal Formation and Tertiary Siwalik Group represent the Infra Tertiary boundary in the Sheikh Buddin hills and Marawat Range. In Central and Eastern Salt Range, Hazara and Kashmir the boundary is represented between the varying Tertiary rocks with also varying older rocks such as Precambrian, Paleozoic and Mesozoic units. K-T boundary in Pakistan represents wide exposures of marine as well as continental condition. Indus Basin of Pakistan holds a large number of section sites for lateral and vertical rapid environmental/climate change in the Cretaceous greenhouse world. Pakistan has much potential for the study of marine as well as terrestrial Precambrian, Paleozoic, Mesozoic and Cenozoic strata, its boundaries, floras and faunas, paleoclimates, extinctions, phylogeny and paleobiogeography