Crocodilians are one of the only two living groups in archosauria, a clade that also includes birds and the all-time favourite prehistoric monsters, dinosaurs and pterosaurs. Crocodilians diverged from their closest extant relatives 240 million years ago, and the common ancestor of all living crocodilians is dated around 70-80 million years ago, in the Cretacic era. Since then, they have experimented very few morphological changes, remaining the semi-aquatic fierce predators we all know. They shared the land with dinosaurs and they survived the massive extinction at the end of the Mesozoic. Now, PhylomeDB extend its vertebrate catalogue to include the phylomes of three of this intimidating animals: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial) (phylomes: 200, 201 and 202). The analyses show that, in syntony with their conserved morphology across time, the evolutionary rate of crocodilians is the slowest in all vertebrates. The comparison with avian genomes allows to infer the genomic content of the basal archosauria and provides an evolutionary landscape for a better understanding of birds and reptiles evolution. You can browse the phylome and find more information in the associated publication:
Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs. Green RE, Braun EL, Armstrong J, Earl D, Nguyen N, Hickey G, Vandewege MW, St John JA, Capella-Gutiérrez S, Castoe TA, Kern C, Fujita MK, Opazo JC, Jurka J, Kojima KK, Caballero J, Hubley RM, Smit AF, Platt RN, Lavoie CA, Ramakodi MP, Finger JW Jr, Suh A, Isberg SR, Miles L, Chong AY, Jaratlerdsiri W, Gongora J, Moran C, Iriarte A, McCormack J, Burgess SC, Edwards SV, Lyons E, Williams C, Breen M, Howard JT, Gresham CR, Peterson DG, Schmitz J, Pollock DD, Haussler D, Triplett EW, Zhang G, Irie N, Jarvis ED, Brochu CA, Schmidt CJ, McCarthy FM, Faircloth BC, Hoffmann FG, Glenn TC, Gabaldón T, Paten B, Ray DA. Science. 2014 Dec 12;346(6215):1254449. doi: 10.1126/science.1254449.