Peer-reviewed publications related to the Chalk Sea Ecosystems Project
Slimehead Size Through Time: Testing the Temperature–Size Relationship in Late Cretaceous Trachichthyidae. Chloe V. Griffiths, James D. Witts, Julie C.S. Brown, Emma L. Bernard, Richard J. Twitchett. Published in Ecology and Evolution, 25th September 2025. https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.72026
As global temperatures rise, fish are predicted to become smaller. Body size is a fundamental trait that impacts many aspects of an animal’s life history and ecology, and understanding how it may respond to climate change in particular fish groups, especially commercial or keystone species, is critical. The slimeheads (Family Trachichthyidae) include several commercially important species, but because they are deep-dwelling, long-lived fish that reproduce slowly, directly testing the temperature–size relationship in this family is challenging. Fortunately, Trachichthyidae have a long evolutionary history beginning in the Cretaceous, and their fossil record provides empirical data on the response of this family to past climate change events. In this study, we leveraged the extensive fossil record of the Late Cretaceous trachichthyid genus Hoplopteryx from the British Chalk Group of southern England, United Kingdom, to test whether its size declined at higher temperatures. Standard Lengths were measured from complete individuals and estimated from partial remains. Seawater palaeotemperature estimates were derived from oxygen stable isotope values (𝛿18O) of the bulk chalk rock surrounding the fossils using standard techniques and assumptions. Individual fish ranged from 56.3 to 262.6 mm in length, and measured seawater temperature estimates ranged from 19.5°C to 27.1°C. Multiple linear regression analyses revealed that the estimated seawater temperature was a significant negative predictor of Standard Length in the most common species, Hoplopteryx lewesiensis, supporting the prediction that higher temperatures led to smaller body size in fish. In addition, carbon stable isotope values (𝛿13C) also significantly negatively predicted the Standard Length of Hoplopteryx spp., suggesting that other environmental factors, such as primary productivity and/or the burial of organic matter, may also have affected body size.
The evolution of bone-eating worm diversity in the Upper Cretaceous Chalk Group of the United Kingdom. Sarah Jamison-Todd, James D. Witts, Marc E. Jones, Deborah Tangunan, Kim Chandler, Paul Bown, Richard J. Twitchett. Published in PLOS One, 3rd April 2025. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0320945
The bone-eating worm Osedax is today a member of the highly adapted invertebrate assemblages associated with whale carcasses on the ocean floor. The worm has also been found in a variety of other vertebrates in marine environments. Osedax borings are represented by the trace fossil Osspecus, which has been identified in fossil whales and marine reptiles, with the earliest occurrence in the Albian. In studies of present-day whale bones it has been found that individual species of Osedax create distinct boring morphologies. The diversity of boring geometries therefore provides a proxy for species diversity that can be applied to the fossil record to better understand the diversity, ecology, and evolution of extinct Osedax species. We examined marine reptile fossils from the Upper Cretaceous Chalk Group of the United Kingdom, and found five previously undocumented boring morphologies. These results, coupled with a re-examination of previous records of Osspecus, led to the naming of seven new ichnospecies. Using nannofossil biostratigraphy from the chalk, we constrained the ages of these occurrences and found a high species diversity in the early Late Cretaceous, indicating either a rapid diversification or an earlier origin for Osedax than previously estimated. Furthermore, we recognise five Cretaceous ichnospecies that are also found in the Cenozoic, three of which are also found in present-day whale bones.
Published academic conference presentation abstracts related to the Chalk Sea Ecosystems Project
Unlocking UK Chalk macrofossil collections using calcareous nannofossil biostratigraphy: Insights into Late Cretaceous ecosystem change, resilience, and extinction. Deborah Tangunan, James D. Witts, Liam Gallagher, Stephen Stukins, Emma Bernard, Katie Collins, Leila D’Souza ,Mike Day, Timothy Ewin, Richie Howard, Zoë Hughes, Marc Jones, Giles Miller, Jonathan A. Todd, Andrew S. Gale, Charlie Underwood, Richard J. Twitchett, and Paul R. Bown. Presented at the European Geosciences Union General Assembly 2026. https://meetingorganizer.copernicus.org/EGU26/EGU26-19472.html
The ChaSE project: Chalk Sea Ecosystems and Cretaceous environmental change in the Chalk Group of the United Kingdom. James Witts, Deborah Tangunan, Emma Bernard, Harriet Bohun, Katie Collins, Leila D’Souza, Mike Day, Timothy A.M. Ewin, Thomas Fogherty, Chloe Griffiths, Richie Howard, Zoë Hughes, Marc Jones, Giles Miller, Kaia Spence, Julie C.S. Brown, Andrew S. Gale, Liam Gallagher, Charlie Underwood, Paul R. Bown, Richard J. Twitchett. Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025. https://doi.org/10.1130/abs/2025AM-8796
Palaeoecological response to Earth System changes across the Cenomanian – Turonian boundary in the UK Chalk Sea. James Witts, Harriet Bohun, Zoë Hughes, Andrew S. Gale, Richard Twitchett. Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025. https://doi.org/10.1130/abs/2025AM-8718
Orbitally driven nannoplankton evidence of surface ocean cooling and productivity in the Late Cretaceous greenhouse world. Deborah Tangunan, Paul R. Bown, Andrew S. Gale, Maria Rose Petrizzo, James D. Witts, and Richard J. Twitchett. Presented at the European Geosciences Union General Assembly, 2025. https://meetingorganizer.copernicus.org/EGU25/EGU25-17546.html
ChaSE 