Gansus zheni enters the LRT with skull data lacking in Gansus yumenensis

The first several specimens
attributed to the bird genus Gansus yumenensis (Hou and Liu 1984, You et al. 2006; Early Cretaceous; Fig. 1) were not complete and none included the skull, mandibles or anterior neck. Here in the large reptile tree (LRT, 2021 taxa) the best data was taken from a freehand drawing.

By happy contrast
Gansus zheni (Liu et al. 2014 BMNHC–Ph 1342; Early Cretaceous; Fig. 1) is known from a complete skeleton. Now it nests between smaller Hongshanornis and similar Iteravis (Fig. 2) in the LRT. These are not aquatic taxa, but likely shoreline taxa.

What was Gansus like, according to the experts?
From Wikipedia,“You et al. (2006) concluded that the anatomical characteristics of Gansus were similar to foot-propelled diving birds, such as Hesperornis (from the Cretaceous) and the loons (Gaviidae) and grebes (Podicipedidae).On the other hand, Li et al. (2011) concluded that Gansus showed a more similar morphology to ducks. Two years later, Nudds et al. (2013) showed that the pectoral limb length proportions of Gansus were most similar to swifts and hummingbirds (Apodiformes), while the pelvic limb length proportions fell within the modern birds (Neornithes), showing similarities with grebes (Podicipedidae), albatross (Diomedeidae) and cormorants (Phalacrocoracidae), suggesting that Gansus was both volant and capable of diving to some degree using either foot-propelled or, perhaps, both its wings and its feet for underwater locomotion.”

Sharp-eyed readers will note
a revision of this portion of the LRT (Fig. 2) that moves a few taxa around. We will look at those in more detail soon. The ancestry of Hesperornis seems particularly novel.

References
Hou L and Liu Z 1984. A new fossil bird from Lower Cretaceous of Gansu and early evolution of birds. Sci. Sin. Ser. B. 27:1296−1302.
You et al. (12 co-authors) 2006. A nearly modern amphibious bird from the Early Cretaceous of Northwestern China. Science 312:1640–1643.
Liu et al. (6 co-authors) 2014. An advanced, new long-legged bird from the Early Cretaceous of the Jehol Group (northeastern China): Insights into the temporal divergence of modern birds. Zootaxa 3884(3):253–266.

wiki/Gansus