UNASSIGNED: @entity1141 ( @entity1141 ) is a condition most notably found in birds, but that is also present in other saurischian dinosaurs and pterosaurs. In birds, skeletal pneumatization occurs where bones are penetrated by pneumatic @entity7261 , membranous extensions that originate from air sacs that serve in the ventilation of the lung. Key questions that remain to be addressed include further characterizing (1) the skeletal features that can be used to infer the presence/absence and extent of @entity1141 in birds and non-avian dinosaurs, and (2) the association between vertebral laminae and specific components of the avian respiratory system. Previous work has used vertebral features such as pneumatic foramina, fossae, and laminae to identify/infer the presence of air sacs and @entity7261 , and to discuss the range of possible functions of such features. Here, we tabulate pneumatic features in the vertebral column of 11 avian taxa, including the flightless ratites and selected members of semi-volant and semi-aquatic Neornithes. We investigate the associations of these osteological features with each other and, in the case of @entity6497 , with the specific presence of pneumatic @entity7261 . We find that the mere presence of vertebral laminae does not indicate the presence of skeletal pneumaticity, since laminae are not always associated with pneumatic foramina or fossae. Nevertheless, laminae are more strongly developed when adjacent to foramina or fossae. In addition, membranous air sac extensions and adjacent musculature share the same attachment points on the vertebrae, rendering the use of such features for reconstructing respiratory soft tissue features ambiguous. Finally, pneumatic @entity7261 attach to the margins of laminae, foramina, and/or fossae prior to their intraosseous course. Similarities in @entity1141 distribution among the examined taxa are concordant with their phylogenetic interrelationships. The possible functions of @entity1141 are discussed in brief, based upon variation in the extent of @entity1141 between taxa with differing ecologies.

Osteological and Soft-Tissue Evidence for Pneumatization in the Cervical Column of the @entity6497 ( XXXX ) and Observations on the Vertebral Columns of Non-Volant, Semi-Volant and Semi-Aquatic Birds.

@entity6497 :: ('8801', 'Species') :: ['Struthio camelus'] @entity1141 :: ('MESH:C535662', 'Disease') :: ['PSP', 'Postcranial skeletal pneumaticity'] @entity7261 :: ('MESH:D004240', 'Disease') :: ['diverticula']
@entity6497 :: (8801,Species) :: ['Struthio camelus']
