Comparison of charadriiform and sphenisciform sterni. A <i>Alca torda</i> (USNM 502382) B <i>Aethia psittacula</i> (NCSM 18514) C <i>Sterna anaethetus</i> (NCSM 17085) D <i>Hydrophasianus chirurgus</i> (USNM 490566) E <i>Eudyptula minor</i> (TMM M-391).
Neil Adam Smith
CC BY 3.0
Smith, N.A. 2010. Taxonomic revision and phylogenetic analysis of the flightless Mancallinae (Aves, Pan-Alcidae) <i>Zookeys</i> 91: 1–116 <a href="https://en.wikipedia.org/wiki/Digital_object_identifier" class="extiw" title="w:Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.3897%2Fzookeys.91.709">10.3897/zookeys.91.709</a>