Miotadorna is a genus of extincttadornineducks from the Miocene of New Zealand. It contains two species, M. sanctibathansi, and M. catrionae (Catriona's shelduck).
M. catrionae, described and named in 2022, is the largest duck species so far discovered in the St Bathans fossil deposits. Both the species name, catrionae, and the common name, Catriona's shelduck, honour co-author Nicholas J. Rawlence's late mother Catriona Drummond. The holotype specimen is a large right humerus. It is noted as being very similar to M. sanctibathansi, but its large size and differing proportions distinguish it from that species. This size difference may represent sexual dimorphism, although the morphological changes are not sufficiently explained by this.[2]Worthyet al., (2022) considered M. catrionae to be a synonym of M. sanctibathansi, as they believed it was more likely that the larger specimen represented a larger sex.[1]