Friday, January 27, 2012

[Paleontology • 2012] Jeholornis palmapenis • A new species of Jeholornis with complete caudal integument

The Early Cretaceous long bony-tailed bird Jeholornis prima displays characters both more basal than Archaeopteryx and more derived, exemplifying the mosaic distribution of advanced avian features that characterises early avian evolution and obfuscates attempts to understand early bird relationships. The current diversity of Jeholornithiformes is controversial, since multiple possibly synonymous genera were named simultaneously. Here, we provide the first definitive evidence of a second species belonging to this clade, and erect the new taxon J. palmapenis sp. nov. This new specimen reveals the tail integument of Jeholornithiformes, the morphology of which appears to have no aerodynamic benefit suggesting this clade evolved plumage patterns that were primarily for display.

Keywords: Jeholornis; feathers; rectrix; long-tailed birds; Jehol Group

Etymology: The Latin species name, palma meaning palm and penis meaning tail, refers to the palm tree like appearance of the preserved rectrices.

Figure 2. Camera lucida drawing of the (A) main slab SDM 20090109.1 and (B) counterslab SDM 20090109.2. Scale bars equal 10 cm.

Figure 5. Detailed photograph of the rectrices preserved in the counter slab of SDM 20090109.2. Scale bar equals 1 cm.

Jingmai K. O'Connor, Chengkai Sun, Xing Xu, Xiaolin Wang and Zhonghe Zhou. 2012. A new species of Jeholornis with complete caudal integument. Historical Biology 24 (1): 29-41.