Spiti (Himachal Pradesh, India)
In 2009, first fish fossils were discovered in Early Triassic strata of Spiti (Indian Himalayas) during a field campaign by the Palaeontological Institute and Museum, University of Zurich, Switzerland, and collaborators. Subsequent fieldwork in 2010 was executed with the goal of finding more fish material. The 2010 expedition focussed on three well-accessible localities near the villages of Guling, Mud, and Tilling (photo below) within Pin Valley (Lahaul and Spiti District, Himachal Pradesh, India), and brought home several additional specimens. This previously unknown fish fauna was recently published in Swiss Journal of Palaeontology.
The Spiti area is famous for the occurrence of Early Triassic outcrops rich in ammonoid and conodont fossils. The fishes occur in Dienerian aged strata of the Mikin Formation and are preserved both in the calcareus nodules and in the intercalated black shale layers. These black shale layers contain evidence for oxygen-depleted conditions during most of the Dienerian time interval, which probably also explains the preservation of fish fossils within these sediments.
Pin Valley is situated at over 3800 metres above sea level and climbing up to the outcrops can be quite exhausting due to the thin air. Nevertheless, the picturesqueness of the Spiti Himalayas, the tasty food, and the geniality of the people make it an amazing place for fielwork. Here are some impressions.
The new fish assemblages discovered during the 2009 and 2010 expeditions include fossils of ray-finned and lobe finned fishes (see paper). Ray-finned fishes are represented by Saurichthys, a parasemionotid, as well as other, indeterminable species. Saurichthys was a cosmopolitan ambush predator during the Triassic. Parasemionotids, which are related to the extant bowfin (Amia calva), likewise had a widespread distribution during the Early Triassic. These finds highlight the similarities between fish faunas that lived in the aftermath of the end-Permian mass extinction, the biggest crisis in the history of life on Earth.