• Amniotes evolved from amphibian ancestors during the Carboniferous period and further diverged into two groups, namely the sauropsids (including all reptiles and birds) and synapsids (including mammals and extinct ancestors like "pelycosaurs" and therapsids). (wikipedia.org)
  • Because the amnion and the fluid it secretes shields the embryo from environmental fluctuations, amniotes can reproduce on dry land by either laying shelled eggs (reptiles, birds and monotremes) or nurturing fertilized eggs within the mother (marsupial and placental mammals), unlike anamniotes (fish and amphibians) that have to spawn in or closely adjacent to aquatic environments. (wikipedia.org)
  • Currently, life-history data for amniotes (birds, mammals, and reptiles) are split among a variety of publicly available databases, data tables embedded in individual papers and books, and species-specific studies by experts. (figshare.com)
  • Two super-groups make up the amniotes: the Synapsida ( Pelycosaurs , Theriodonts and mammals ) and the Sauropsida (all reptiles , including dinosaurs and birds ). (wikipedia.org)
  • All ectothermic amniotes are reptiles. (enchantedlearning.com)
  • Thus, our analysis yields novel insights into features of the segmentation clock that are evolutionarily basal to amniotes versus those that are specific to mammals, Lepidosaurian reptiles, or Archosaurian reptiles. (xenbase.org)
  • Microsaurs lived during the Carboniferous period, when the forebears of modern mammals and reptiles, called amniotes, first appeared. (jordantimes.com)
  • Mann said the research suggests not only that microsaurs might be early relatives of reptiles, but also that the ability to burrow may have played a bigger role in the origin of amniotes than originally thought. (jordantimes.com)
  • Amniotes are animals belonging to the clade Amniota, a large group of tetrapod vertebrates that comprises the vast majority of living terrestrial vertebrates. (wikipedia.org)
  • After the Carboniferous rainforest collapse, amniotes spread around Earth's land and became the dominant land vertebrates, and soon diverged into the synapsids and sauropsids, whose lineages both still persist today. (wikipedia.org)
  • Older sources, particularly before the 20th century, may refer to amniotes as "higher vertebrates" and anamniotes as "lower vertebrates", based on the antiquated idea of the evolutionary great chain of being. (wikipedia.org)
  • Most vertebrates that live on land are amniotes, as are most of the air-breathing animals of the sea. (wikipedia.org)
  • Using genomic sequence, RNA-Seq transcriptomic data, and in situ hybridization analysis of somite-stage embryos, we carried out comparative analyses of key genes and found that the anole segmentation clock displays features common to both amniote and anamniote vertebrates. (xenbase.org)
  • The non-visual opsins: eighteen in the ancestor of vertebrates, astonishing increase in ray-finned fish, and loss in amniotes. (lsu.edu)
  • Our results emphasize physiological aspects of adaptive convergence among fossil and extant marine amniotes and add to our current understanding of plesiosaur evolution. (peerj.com)
  • Aquatic Adaptations in the Limbs of Amniotes" In Fins into Limbs: Evolution, Development, and Transformation edited by Brian K. Hall, 310-322. (degruyter.com)
  • Here, we review studies of sex chromosome evolution in amniotes and the ways in which the field of research has been affected by the advent of BAC libraries. (harvard.edu)
  • New habits and heavier bodies meant further evolution for the amniotes, both in behavior and anatomy. (wikipedia.org)
  • Morphology and evolution of the egg of oviparous amniotes. (wikipedia.org)
  • Molecular diversity and evolution of neuron types in the amniote brain. (mpg.de)
  • 2012 . Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes. (sc.edu)
  • 694 The first amniotes, referred to as "basal amniotes", resembled small lizards and evolved from semiaquatic reptiliomorphs about 312 million years ago during the Carboniferous period. (wikipedia.org)
  • The ancestors of true amniotes, such as Casineria kiddi, which lived about 340 million years ago, evolved from amphibian reptiliomorphs and resembled small lizards. (wikipedia.org)
  • The first amniotes, such as Casineria , looked like small lizards. (wikipedia.org)
  • Zoologists characterize amniotes in part by embryonic development that includes the formation of several extensive membranes, the amnion, chorion, and allantois. (wikipedia.org)
  • In amniotes, the transition from a two-layered periderm to a cornified epithelium is triggered by thyroid hormone during embryonic development, rather than by metamorphosis. (wikipedia.org)
  • The 'invention' of the cleidoic egg , and its embryonic membranes, is the main reason why the eggs of an amniote do not need to be laid in water. (wikipedia.org)
  • Amniotes develop directly into a (typically) terrestrial form with limbs and a thick stratified epithelium (rather than first entering a feeding larval tadpole stage followed by metamorphosis, as amphibians do). (wikipedia.org)
  • Thus, as distinct from the amphibians , amniotes are truly terrestrial . (wikipedia.org)
  • The embryos of amniotes are either laid as eggs or develop in the female. (wikipedia.org)
  • Transgenic quail that ubiquitously express fluorescent proteins provide a novel amniote model system that permits investigations in living embryos with unprecedented spatiotemporal resolution. (usc.edu)
  • Very early in the evolutionary history of amniotes, they split into two main lines, the synapsids and the sauropsids , both of which persist into the modern era. (wikipedia.org)
  • Somitogenesis in the anole lizard and alligator reveals evolutionary convergence and divergence in the amniote segmentation clock . (xenbase.org)
  • One can assume the ancestors of the amniotes laid their eggs in moist places, as such modest-sized animals would not have difficulty finding depressions under fallen logs or other suitable places in the ancient forests, and dry conditions were probably not the main reason why the soft shell emerged. (wikipedia.org)
  • After the egg developed these structures, further sophistication allowed amniotes to lay much bigger eggs in much drier habitats. (wikipedia.org)
  • Bigger eggs allowed for bigger offspring, and bigger adults could produce bigger eggs, so amniotes grew bigger than their ancestors. (wikipedia.org)
  • Multi-scale quantification of tissue behavior during amniote embryo axis elongation Development. (usc.edu)
  • In: S. Sumida and K. Martin (eds) Amniote origins: completing the transition to land . (wikipedia.org)
  • The advanced snakes (Caenophidia), the important amniote lineage encompassing more than 3,000 living species, possess highly conserved female heterogamety across all families. (karger.com)
  • Microsaurs have recently become important in understanding the origins of amniotes," he said. (jordantimes.com)
  • The oldest tetrapod fossils are footprints of Middle Devonian age, and, in Upper Carboniferous (Pennsylvanian) strata, the first fossils of amniotes are known. (palaeo-electronica.org)
  • Druge kladističke definicije u potpunosti napuštaju pojam gmizavac u korist klade Sauropsida , koja se odnosi na sve amniote koji su bliži modernim reptilima nego sisavcima. (wikipedia.org)
  • This let amniotes move into environments that had less water . (wikipedia.org)
  • Variability among sex chromosome pairs in amniotes denotes a dynamic history. (harvard.edu)
  • Since amniotes diverged from a common ancestor, their sex chromosome pairs and, more broadly, sex-determining mechanisms have changed reversibly and frequently. (harvard.edu)
  • The skeletal remains of amniotes have at least two pairs of sacral ribs , a sternum in the pectoral girdle (shoulders area) and an astragalus bone in the ankle . (wikipedia.org)
  • In amniotes the inner anatomy of the egg has evolved further and new structures have developed to take care of the gas exchanges between the embryo and the atmosphere, as well as dealing with the waste problems. (wikipedia.org)
  • 1995. A reevaluation of early amniote phylogeny. (wikipedia.org)
  • The following image is an overview of the transitions occurring in early heart development in amniotes. (medscape.com)
  • This box provides an overview of the transitions occurring in early heart development in amniotes (on the basis of the events in mouse development). (medscape.com)
  • And amniote animals share with frogs and salamanders the property of having four legs - they're tetrapods . (don-lindsay-archive.org)
  • With these techniques, researchers have identified differences and similarities in sex chromosome content and organization across amniotes and have addressed hypotheses regarding the frequency and direction of past changes. (harvard.edu)
  • Features of amniotes evolved for survival on land include a sturdy but porous leathery or hard eggshell and an allantois that facilitates respiration while providing a reservoir for disposal of wastes. (wikipedia.org)
  • In order to facilitate comparative analyses between amniote life-history data, we created a database compiled from peer-reviewed studies on individual species, macroecological studies of multiple species, existing life-history databases, and other aggregated sources as well as published books and other compilations. (figshare.com)
  • High-contrast en bloc staining of mouse whole-brain and human brain samples for EM-based connectomics. (mpg.de)