Conservation implications of a new fossil species of hopping-mouse, <i>Notomys magnus</i> sp. nov. (Rodentia: Muridae), from the Broken River Region, northeastern Queensland
Creators: name: Vakil, Vikram
name: Cramb, Jonathan
name: Price, Gilbert J.
name: Webb, Gregory E.
name: Louys, Julien
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Evolutionary Biology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Biological Sciences not elsewhere classified

description: The Australian hopping-mouse <i>Notomys</i> includes 10 species, eight of which are considered extinct, vulnerable, near-threatened or endangered. Here we report a new fossil species from the Broken River Region, northeastern Queensland. <i>Notomys magnus</i> sp. nov. is represented by craniodental material from late Quaternary cave deposits. It was a relatively large-bodied species of <i>Notomys</i> with a mass estimated to be <i>ca</i> 83 g. <i>Notomys magnus</i> sp. nov. is immediately distinguishable from the spinifex hopping-mouse (<i>Notomys alexis</i>), the northern hopping-mouse (<i>Notomys aquilo</i>), the fawn hopping-mouse (<i>Notomys cervinus</i>), the dusky hopping-mouse (<i>Notomys fuscus</i>), Mitchell’s hopping-mouse (<i>Notomys mitchellii</i>) and the big-eared hopping-mouse (<i>Notomys macrotis</i>) by its larger size (especially its longer upper molar crown length). <i>Notomys magnus</i> sp. nov. differs from the large-bodied Darling Downs hopping-mouse (<i>Notomys mordax</i>), long-tailed hopping-mouse (<i>Notomys longicaudatus</i>), short-tailed hopping-mouse (<i>Notomys amplus</i>) and broad-cheeked hopping-mouse (<i>Notomys robustus</i>) by possessing a unique first upper molar (M<sup>1</sup>) morphology including relatively well-developed buccal cusps, cusp T1 prominently isolated from T4, a relatively narrow posterior loph and an incipient anterior accessory cusp. Fossils of <i>N. magnus</i> sp. nov. are found in association with remains of several arid-adapted taxa, including the plains mouse (<i>Pseudomys australis</i>), the northern pig-footed bandicoot (<i>Chaeropus yirratji</i>), and <i>N. longicaudatus</i>, possibly indicating that <i>N. magnus</i> sp. nov. was also arid-adapted. Dating of fossil deposits containing <i>N. magnus</i> sp. nov. demonstrates that it was extant in the mid-Holocene (<i>ca</i> 8.5 ka) so it may have been still extant at the time of European colonization but suffered extinction soon after, mirroring the fate of similarly arid-adapted contemporaneous taxa (<i>Chaeropus yirratji</i> and <i>N. longicaudatus).</i> Historical extinctions in <i>Notomys</i> are biased towards larger species (<i>N. amplus</i>, <i>N. longicaudatus</i> and <i>N. robustus</i>), and the discovery of <i>N. magnus</i> sp. nov. adds further to that list. Given the already high number of extinct and endangered species within <i>Notomys</i>, the discovery of another member that suffered geologically recent extinction has conservation implications for modern critical weight range mammals (including other species of rodents) that are particularly susceptible to extinction. Most historical extinctions of critical weight range mammals were in southern and central Australia, but the discovery of <i>N. magnus</i> sp. nov. suggests that species in the tropical north also were detrimentally affected. <i>Vikram Vakil [vikram.vakil@uqconnect.edu.au], School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia;</i> <i>Jonathan Cramb [jonathan.cramb@qm.qld.gov.au], Queensland Museum, Brisbane, Australia;</i> <i>Gilbert J. Price [g.price1@uq.edu.au], School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia;</i> <i>Gregory E. Webb [g.webb@uq.edu.au], School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia;</i> <i>Julien Louys [j.louys@griffith.edu.au], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Queensland 4101, Australia.</i>