Spitsbergen (Svalbard, Norway)
In summer 2008, members of the Palaeontological Institute and Museum of the University of Zurich, (Switzerland) and the Natural History Museum of the University of Oslo (Norway) conducted fieldwork on the Arctic island of Spitsbergen (Svalbard archipelago, Norway) to explore the fish fossils of the Early Triassic 'fish horizon'. The field party camped on the western slope of Stensiöfjellet (Mt. Stensiö), wich is located in Sassendalen (Sassen Valley) ca. 60 km east of Longyearbyen.
For me, this was the first palaeontological expedition abroad. I was quite excited to be a part of this field campaign to the remote island of Spitsbergen, high in the Arctic. Due to bad weather, we were only able to stay 9 days in the field, but the expedition was successful nonetheless. Here are some impressions from our fieldwork:
A video montage (with music) of our fieldwork on Spitsbergen can be found here.
Among the collected fossils was a partial skeleton of the hybodontiform chondrichthyan Palaeobates polaris, the second specimen of this rare shark. A publication on this interesting specimen was published in 2010 in Journal of Vertebrate Paleontology.
The fossil of P. polaris found in 2008 is more complete than the type specimen of P. polaris described by Erik Stensiö in 1921. The new find contains the left mandibular branch with associated dentition and labial cartilage as well as elements of the hyoid arch and a portion of the anterior dorsal fin. P. polaris shares with the other species of the genus Palaeobates the same tooth histology (orthodont teeth), but the ornamentation of the teeth is different and reminiscent of teeth ascribed to Acrodus. Below is a photograph of the specimen of P. polaris found in 2008.
Another interesting fossil collected during the 2008 field campaign is a huge, largely complete skull of a Birgeria sp. (> 1,50 m body length). The concretion containing this fossil is shattered into numerous pieces, some of which we depict in an article published in the journal PLoS ONE (open access) in March 2014. In this paper, we show that, contrary to the view of some researchers, marine predators including large fish and marine tetrapods (amphibians, reptiles) were widespread and relatively diverse during the Early Triassic. Consequently, this means that in the aftermath of the end-Permian mass extinction, the largest of its kind, relatively complex food webs were re-established faster than previously suggested. The following figure shows life reconstructions of various marine vertebrates that had widespread occurrences during the Ealry Triassic and/or early Middle Triassic (modified from our paper; reconstructions by Beat Scheffold and Nadine Bösch).
Additional specimens recovered during the Swiss-Norwegian expedition include a well-preserved partial skeleton of the Triassic ambush predator Saurichthys. Saurichthys fossils from the Early Triassic aged deposits of Spitsbergen have been comprehensively studied in the early 20th century, but have not been studied again since E. Stensiö's monograph published in 1925. Four species of Saurichthys are described from Spitsbergen, of which predominantely skull (cranium) remains are known. The body (postcranium) of these peculiar fishes contains many specialized characters, which are useful to distinguish species and which also are of evolutionary significance. However, up to now only seven Saurichthys fossils were known that show postcranial features. During the 2008 expedition, we collected the eighth and as yet most complete postcranial fossil of a Saurichthys from Spitsbergen (shown below). A reconstruction of Saurichthys is shown below the fossil.
The fossilized part of the new individual has a length of 32 cm. The specimen shows the hind portion of the animal, including the fragmentary pelvic fins (left), the dorsal and anal fins (middle), and an incomplete tail fin (right). The head and front body portion of this about 80 cm long animal could not be found in the field. The body of Saurichthys comprises several scale rows along the body, with each species showing its own, characteristic pattern. Based on the scales, this individual can be referred to Saurichthys wimani, an up to now poorly known species that was first described from Spitsbergen by A.S. Woodward in 1912. It was named after Swedish palaeontologist Carl Wiman (1867–1944). S. wimani is characterized by several 'primitive' features, such as the more extensive scale covering and segmented fin rays. The results of our study, which will help to better understand the early evolution of these highly specialized fishes, are published in the journal Freiberger Forschungshefte (see also: Researchgate).
Fossils of Saurichthys are known from Triassic deposits around the world. We also collected a few skulls of Saurichthys during fieldwork in the western USA. Saurichthys was the first specialized ambush predators among ray-finned fishes.
Other fossils from the Early Triassic of Spitsbergen are currently under study.