The alligator gut microbiome and implications for archosaur symbioses

• Published in: Scientific reports Vol. 3; no. 1; p. 2877
• Main Authors: Keenan, Sarah W., Engel, Annette Summers, Elsey, Ruth M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07.10.2013; Nature Publishing Group
• Subjects: 631/158/855; 631/181/2481; 631/326/2565/2134; 704/2151/414; Alligators; Alligators and Crocodiles - microbiology; Alligators and Crocodiles - physiology; Animals; Aquatic reptiles; Archosauria; Bacteria - classification; Bacteria - genetics; Biodiversity; Digestive system; Dinosaurs; DNA, Bacterial - genetics; Gastrointestinal tract; Gastrointestinal Tract - microbiology; Humanities and Social Sciences; Intestinal microflora; Louisiana; Microbiota; multidisciplinary; Phylogeny; Reptiles; Science; Symbiosis; Vertebrates; Louisiana
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep02877

Among vertebrate gastrointestinal microbiome studies, complete representation of taxa is limited, particularly among reptiles. Here, we provide evidence for previously unrecognized host-microbiome associations along the gastrointestinal tract from the American alligator, a crown archosaur with shared ancestry to extinct taxa, including dinosaurs. Microbiome compositional variations reveal that the digestive system consists of multiple, longitudinally heterogeneous microbiomes that strongly correlate to specific gastrointestinal tract organs, regardless of rearing histories or feeding status. A core alligator gut microbiome comprised of Fusobacteria, but depleted in Bacteroidetes and Proteobacteria common to mammalians, is compositionally unique from other vertebrate gut microbiomes, including other reptiles, fish and herbivorous and carnivorous mammals. As such, modern alligator gut microbiomes advance our understanding of archosaur gut microbiome evolution, particularly if conserved host ecology has retained archosaur-specific symbioses over geologic time.