Monday, August 3, 2015

[Paleontology • 2015] The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life

Fig. 6. A reconstruction of the Strawberry Bank scene, by J. Sibbick. Situated near a subtropical island on the northwestern margin of Tethys, the shallow seas of Strawberry Bank provided a habitat for diverse macrofauna, amongst which early teleost fishes were the most abundant component. Here larger Pachycormus hunts shoaling Leptolepis, and opportunistically takes a mayfly that has alighted on the sea surface.

The Strawberry Bank Lagerstätte provides a rich insight into Early Jurassic marine vertebrate life, revealing exquisite anatomical detail of marine reptiles and large pachycormid fishes thanks to exceptional preservation, and especially the uncrushed, 3D nature of the fossils. The site documents a fauna of Early Jurassic nektonic marine animals (five species of fishes, one species of marine crocodilian, two species of ichthyosaurs, cephalopods and crustaceans), but also over 20 species of insects. Unlike other fossil sites of similar age, the 3D preservation at Strawberry Bank provides unique evidence on palatal and braincase structures in the fishes and reptiles. The age of the site is important, documenting a marine ecosystem during recovery from the end-Triassic mass extinction, but also exactly coincident with the height of the Toarcian Oceanic Anoxic Event, a further time of turmoil in evolution.

Fig. 5. Reptiles from Strawberry Bank. (a, b) The skull of a juvenile ichthyosaur, Hauffiopteryx typicus (BRLSI M1399), in right lateral view (a), and in dorsal view (b), to show the lack of compression. (c) Articulated juvenile ichthyosaur, Stenopterygius triscissus (BRLSI M1409). (d) Skull of a subadult thalattosuchian crocodile Pelagosaurus typus (BRLSI M1413). (e) Articulated infant thalattosuchian Pelagosaurus typus (BRLSI M1418).

Matt Williams, Michael J. Benton and Andrew Ross. 2015. The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life. Journal of the Geological Society. doi: 10.1144/jgs2014-144

Outstanding Jurassic Fossils Rediscovered After More Than 100 Years