The John C. Marsden Medal

Prizes of £500 and a medal will be awarded for the best doctoral thesis in biology covering areas other than botany (algae, fungi or plants), as judged by a paper published in the Linnean Society Journals.

Dr John C. Marsden was the Executive Secretary of the Society from 1989 to 2004 and was elected as a Fellow honoris causa in 2005 in recognition of his services to the Society. The medal is awarded annually in Dr John C. Marsden's memory and awards the best thesis as judged by a paper published in one of the Linnean Society's journals. It is open to papers contributing to a PhD thesis, and published with the PhD student as first author.

Enter the prize by submitting a paper to a Linnean Society journal.

• The paper must be published in advanced access in one of the Linnean journals in the calendar year prior to the award year.
• There must be no more than two years between the date of submission to the journal (aka the date that the work is being submitted for assessment for the award) and the date that the thesis was awarded. Ongoing work that is being carried out by the PhD student but has not yet been submitted as a thesis is eligible, as it is considered not to have exceeded the two-year window.
• The paper must go through the peer review system and be accepted for publication (i.e. prize submissions that are not accepted for publication will be ejected).
• There must be confirmation from the PhD supervisor that the work has been carried out by the student.
• In the case of a multi-author paper, the PhD student must be the first author, and the supervisor must confirm the contribution the student has made.
• The nominated student cannot, at the time of nomination, be a member of the Linnean Society Council, or a family member.

Lívia Roese-Miron

'I am deeply honoured to receive the John C. Marsden Medal. This recognition reflects the efforts behind this work and highlights the importance of studying synapsid evolution. I am especially grateful to my co-authors and mentors, whose support and insight were essential to this research.'

Winning Paper: Lívia Roese-Miron, Fernando Abdala, Flávio Augusto Pretto, Rodrigo Temp Müller, Iasmim Michelotti da Costa, Marcelo Ricardo Sánchez-Villagra, Leonardo Kerber. Skull anatomy and endocranial casts of Siriusgnathus niemeyerorum (Cynodontia: Cynognathia) from the Late Triassic of Brazil: implications for the evolution of traversodontids, Zoological Journal of the Linnean Society, Volume 205, Issue 1, September 2025, zlaf107, https://doi.org/10.1093/zoolinnean/zlaf107

First emerging in the Late Permian, cynodonts mostly went extinct in the Triassic with only a few lineages surviving, including the lineage that would evolve into modern mammals. Roese-Miron et al. (2025) provide a detailed analysis of a nearly complete skull of Siriusgnathus niemeyerorum, a cynodont that lived over 200 million years ago. Using high-resolution CT scanning, they reconstructed internal features of the skull including the first ever descriptions of the cranial nerves and inner ear canal of the species. The researchers discovered new features associated with facial mobility, a finding with implications for how these ancient animals fed, defended themselves and socialised. 

From the Editor: ‘I was impressed by the quality of the figures and the analytical rigour of this study. I think it is simply amazing we can use technology to study the nervous system of an animal that lived over 200 million years ago.’ —Dr Jeff Streicher, Editor-in-Chief, Zoological Journal of the Linnean Society

Wenjie Zhu

‘I am honoured and humbled to receive this award. It recognises work on the multispecies coalescent, where I learned that uncertainty in biology is often not noise to be eliminated, but signal to be understood. Beyond acknowledging past work, this award also motivates my ongoing research.’

Winning Paper: Wenjie Zhu, Sebastian Höhna. Two-step species tree inference under the multispecies coalescent using full-likelihood, Evolutionary Journal of the Linnean Society, Volume 4, Issue 1, 2025, kzaf018, https://doi.org/10.1093/evolinnean/kzaf018

Inferring species relationships is challenging because different genes may show conflicting histories, which the multispecies coalescent (MSC) model explicitly accounts for. This study introduces a two-step approach, providing a novel full-likelihood methodology for MSC inference that first estimates gene trees and then infers the species tree, combining computational efficiency with statistical rigour. Simulations and an analysis of gibbons show that the two-step approach performs consistently well, offering a practical, innovative solution for large genomic datasets and advancing our ability to reconstruct complex evolutionary histories.

From the Editor: ‘This paper stands out for addressing the trade-off between statistical rigour and computational feasibility in species tree inference. Its two-step, full-likelihood framework under the multispecies coalescent, delivers both methodological innovation and clear guidance on when different approaches succeed or fail.’ —Professor Julia Day, Editor-in-Chief, Evolutionary Journal of the Linnean Society