Kim et al. (2012) recently reported, “Trackways with large, pes-only tracks with lengths up to 39 cm, characterized by elongate, subtriangular outlines, impressions of four digits and a subangular heel, are attributed to plantigrade pterodactyloids and assigned to
Haenamichnus gainensis ichnosp. nov.”
Kim et al. (2012) were unable to find any manus impressions of these large tracks which they attributed to pterosaurs (Fig. 1) . [Nice to get further vindication evidence, even if not attributed or referenced.] Other than reports by Peters (2000, 2011) these Korean tracks are the first bipedal pterosaur tracks described.)
Finding Candidate Trackmakers
Kim et al. (2012) did not attempt to determine a specific pterosaur trackmaker for the Gain trackways. Taking available data and matching it to pterosaur pedes published in Peters (2011) several suitable candidate trackmakers are here identified (Fig. 3), all from the same monophyletic clade and all with representatives from Asia. These include Shenzhoupterus, Sinopterus and Tupuxuara. The only catch is, the Korean tracks were ~4x larger than the skeletal specimens and distinct from the original Haenamichnus tracks (also from Korea) which were attributable to azhdarchids, which had relatively smaller feet and longer legs producing a longer relative stride. Now the fun (= educated guesswork) begins.
So How Big Were These Korean Pterosaurs?
Pterosaurs with 39 cm long feet were probably taller than a 6 foot tall human (Fig. 3). The ichnites were distinct from those of azhdarchids, but close to those in the Shenzhoupterus/Tupuxuara clade. Such a jump in size probably indicates a distinct cranial morphology from known smaller sisters (Fig. 3). The relatively shorter strides of the Gain pterosaurs (shorter than in Haenimichnus) is likely due to their relatively shorter legs. These giant pterosaurs held their wings above the matrix while walking as demonstrated earlier in this animation of Pteranodon, an unrelated pterosaur with a similar build.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Kim JY, Lockley MG, Kim KS, Seo SJ and Lim JD 2012. Enigmatic Giant Pterosaur Tracks and Associated Ichnofauna from the Cretaceous of Korea: Implication for the Bipedal Locomotion of Pterosaurs. Ichnos 19 (1-2): 50-65.DOI:10.1080/10420940.2011.625779 online
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods. Ichnos, 7: 11-41
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605