Septencoracias morsensis (Bourdon et al., 2016; Eocene 54mya; 25 cm length) is close to an extinct kingfisher, as originally identified, but closer to terns and tropicbirds(below). A tiny claw remained on manual digit 1.

Thalasseus bergii (aka: Sterna bergii; Lichtenstein 1823; 50cm tall) is the extant greater crested tern, a sea bird capable of flying great distances and feeding by plunge diving. Terns are traditionally related to gulls, skimmers and skuas. Here the resemblance to Rhynochetos extends to the head crest.

Bourdon E, Kristoffersen AV and Bonde N 2016. A roller-like bird (Coracii) from the Early Eocene of Denmark. Scientific Reports. 6. 34050. doi:10.1038/srep34050

Lichtenstein M 1823. Published in:Lichtenstein, H. 1823, pp. x 118 pp., Königl. Universität, Berlin

wiki/Greater_crested_tern
wiki/Septencoracias