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Crop for seed-eating found in Hongshanornis and Sapeornis (abstract)



From: Ben Creisler
bh480@scn.org

The article has just been posted. Here's the abstract and 
the link:

Xiaoting Zheng, Larry D. Martin, Zhonghe Zhou, David A. 
Burnham, Fucheng Zhang, and Desui Miao (2011) 
Fossil evidence of avian crops from the Early Cretaceous 
of China.
Proceedings of the National Academy of Sciences (advance 
online publication)
doi: 10.1073/pnas.1112694108 
http://www.pnas.org/content/early/2011/08/29/1112694108.ab
stract


Abstract
The crop is characteristic of seed-eating birds today, 
yet little is known about its early history despite 
remarkable discoveries of many Mesozoic seed-eating birds 
in the past decade. Here we report the discovery of some 
early fossil evidence for the presence of a crop in 
birds. Two Early Cretaceous birds, the basal ornithurine 
Hongshanornis and a basal avian Sapeornis, demonstrate 
that an essentially modern avian digestive system formed 
early in avian evolution. The discovery of a crop in two 
phylogenetically remote lineages of Early Cretaceous 
birds and its absence in most intervening forms indicates 
that it was independently acquired as a specialized seed-
eating adaptation. Finally, the reduction or loss of 
teeth in the forms showing seed-filled crops suggests 
that granivory was possibly one of the factors that 
resulted in the reduction of teeth in early birds.