Variable characters of the pelican tarsometatarsus and their distribution across Pelecanus species.

See text and Table 1 for the full list of specimens examined. The states in P. crispus, P. onocrotalus, and P. rufescens are scored from illustrations in ref. [23].Characters:1. Medial hypotarsal crest: parallel to the tarsometatarsus shaft (0); ‘slanting’ with the proximal end located more dorsal relative to the distal end (1).2. Attachment of the extensor retinaculum just medial to the dorsal pneumatic opening on the proximal end of the tarsometatarsus: short, either not reaching or just reaching distally to the proximodistal midpoint of the pneumatic opening (0); longer, extending distal to the proximodistal midpoint of the opening (1).3. Trochlea II and IV: extend about equally far distally (0); trochlea II extends more distal than trochlea IV (1).4. Concave area on the medial face of trochlea II plantar to the collateral ligamental pit: absent (0); present (1).5. Proximal face of the medial hypotarsal crest: concave with a ridge bounding its edge (0); not concave and ridge absent (1).Variable characters of the pelican tarsometatarsus and their distribution across Pelecanus species.