amniote

Researchers believe the creature is a "stem amniote" _ a likely ancestor of several groups of land-dwelling animals that later differentiated into modern mammals, birds and reptiles.

The origin and early evolutionary history of amniotes. Trends in Ecology and Evolution, 12, pp.

We applied our methods to DNA sequences from two nuclear (18S and 28S) and three mitochondrial genes (12S, 16S, valine tRNA) taken from representative taxa from a relatively noncontroversial and well-studied four-taxon amniote phylogeny (Sceloporus undulatus, Alligator mississippiensis, Gallus gallus, and Mus musculus: alignments [TABULAR DATA FOR TABLE 1 OMITTED] and GENBANK accession numbers as described in Hedges et al.

"After the recent discovery of mesosaur embryos, we can state with a high degree of confidence that embryo retention developed early in amniote evolution, given that mesosaurs are among the basal-most reptiles and that they date from the Early Permian around 280 million years ago," she asserted.

(2007): Impedance-matching hearing in Paleozoic reptiles: evidence of advanced sensory perception at an early stage of amniote evolution.

By double-clicking on a picture, the student views a pop-up window with a list of traits (eukaryotic cells, amniote egg, jaws, etc.) belonging to that organism.

* Unlike other mammals, monotremes, like the platypus, never evolved to give live birth, but instead lay eggs like their amniote ancestors.

Knowing how a basic amniote embryo ends up developing into something so radically different could shed light on turtle history, says paleontologist Michael Lee of the South Australian Museum at the University of Adelaide.

(1988): Amniote phylogeny and the importance of fossils.

A time of forests, swamps, seed ferns, mosses, lycopods and the origin of the amniote egg.

The water-tight amniote egg of reptiles was somewhat larger and still had to pass through this circular ring of bone.

The brain-body ratios of amphibians are even less than those in reptiles (Jerison, 2001), and as discussed above, their fore-brains lack the thalamopallial circuitry of amniote brains.

Common Leaf-tailed Geckos (Uroplatus fimbriatus) have the distinction of having more teeth than any other amniote (terrestrial vertebrate).

Amniote origins: completing the transition to land.

For the analysis, Rieppel and deBraga compiled an extensive data matrix for amniota (reptiles, birds, and mammals) that included 33 amniote groups and 168 characteristics of their bones -- an important physical characteristic in defining clades.