This volume contains the following three contributions:
Chapter 1. Dienerian (Early Triassic) ammonoids and the Early Triassic biotic recovery: a review (Pages: 1-9) / David Ware, Hugo Bucher
Chapter 2. Griesbachian and Dienerian (Early Triassic) ammonoids from the Salt Range, Pakistan (Pages: 11-175) / David Ware, Hugo Bucher, Thomas Brühwiler, Elke Schneebeli-Hermann, Peter A. Hochuli†, Ghazala Roohi, Khalil Ur-Rehman, Amir Yaseen
Intensive and bedrock controlled sampling of four areas (Nammal Nala, Chiddru, Amb and Wargal) in the Salt Range yielded abundant well-preserved Griesbachian and Dienerian (Early Triassic) ammonoids. This material allows establishing a new, high-resolution biostratigraphical frame and an extensive revision of the taxonomy. The Griesbachian is represented by (in ascending order) the Hypophiceras cf. H. gracile Regional Zone, the Ophiceras connectens Regional Zone and the Ophiceras sakuntala Regional Zone. The Dienerian comprises 12 distinct regional zones leading to a threefold subdivision into lower, middle and upper Dienerian. The lower Dienerian, based on the occurrence of the genus Gyronites, can be divided into the Gyronites dubius Regional Zone, the Gyronites plicosus Regional Zone and the Gyronites frequens Regional Zone, in ascending order. The middle Dienerian, based on the occurrence of the genus Ambites, can be divided into five zones: the Ambites atavus Regional Zone, the Ambites radiatus Regional Zone, the Ambites discus Regional Zone, the Ambites superior Regional Zone and the Ambites lilangensis Regional Zone. The upper Dienerian, whose base is defined by the earliest representatives of Paranoritidae, can be divided into four zones: the Vavilovites cf. V. sverdrupi Regional Zone, the Kingites davidsonianus Regional Zone, the Koninckites vetustus Regional Zone and the Awanites awani Regional Zone. Correlations with basins outside the Northern Indian Margin are difficult because of the scarcity of such highly resolved studies on Dienerian ammonoids. Emended diagnoses and detailed synonymy lists are provided for most previously known taxa. In addition, five new genera (Kyoktites, Ghazalaites, Pashtunites, Awanites and Subacerites) and 18 new species (Kyoktites hebeiseni, Ghazalaites roohii, Gyronites schwanderi, Ambites tenuis, Ambites bojeseni, Ambites subradiatus, Ambites bjerageri, Awanites awani, Koiloceras sahibi, Bukkenites sakesarensis, Proptychites wargalensis, Mullericeras shigetai, Mullericeras indusense, Mullericeras niazii, Ussuridiscus ventriosus, Ussuridiscus ornatus, Pseudosageceras simplelobatum and Subacerites friski) are described.
Chapter 3. Dienerian (Early Triassic) ammonoids from Spiti, Himachal Pradesh, India (Pages: 177-241) / David Ware, Hugo Bucher, Thomas Brühwiler, Leopold Krystyn
The results of a high resolution bedrock controlled sampling of Mud, Guling and Lalung in the Spiti District, India are presented. These areas yielded abundant and rather well preserved Dienerian ammonoids, which compare well with the revised ammonoid successions from the Salt Range (Pakistan). The Dienerian ammonoid faunas from both regions are remarkably similar and the new threefold subdivision of the Dienerian (early, middle and late) proposed in the Salt Range also applies to Spiti. Moreover, 10 out of the 12 Dienerian regional zones defined in the Salt Range are recognized in Spiti, with the same associations of characteristic species. Thus the initial biostratigraphical scheme established in the Salt Range can be reproduced laterally and is valid throughout most of the Northern Indian Margin. The four new species Gyronites levilatus, Gyronites bullatus, Ambites nyingmai and Vavilovites meridialis are introduced.