Figure 8 in Oldest fossil loon documents a pronounced ecomorphological shift in the evolution of gaviiform birds

Figure 8. Summary of phylogenetic interrelationships and stratigraphic occurrences of stem group Gaviiformes and other taxa of Aequornithes; the phylogeny of the extant taxa is based on the studies by Prum et al. (2015) and Kuhl et al. (2021) and differs from the tree topology obtained in the morphology-based analysis performed in the present study. For gaviiform birds, the nodes are characterized by the following characters: (1) hypotarsus with distinct sulci for tendons of musculus flexor hallucis longus and m. flexor perforatus digiti 2; (2) humerus with elongated tuberculum supracondylare ventrale; tibiotarsus with narrow and strongly elongated cristae cnemiales; (3) distal end of ulna with enlarged tuberculum carpale; os metacarpale alulare long and without well-delimited processus extensorius and processus alularis (the carpometacarpus of Colymbiculus is unknown); femur strongly abbreviated and stout; and (4) os carpi ulnare with distinct notch for tendon of musculus ulnometacarpalis ventralis. Stratigraphic occurrences of non-gaviiform Aequornithes (red bars) are from Mayr (2022); the interrupted bars indicate uncertain fossil records for Pelecanidae and Sulidae.Published as part of Mayr, Gerald & Kitchener, Andrew C., 2022, Oldest fossil loon documents a pronounced ecomorphological shift in the evolution of gaviiform birds, pp. 1431-1450 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 196 (4) on page 1442, DOI: 10.1093/zoolinnean/zlac045, http://zenodo.org/record/739062