| Lissamphibia Fossil range: Early Triassic - Recent |
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.jpg/230px-Salamandra_salamandra_(Marek_Szczepanek).jpg) The fire salamander
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Anura |
The subclass Lissamphibia includes all recent amphibians. The Early Triassic (also known as Lower Triassic, Buntsandstein, or Scythian) is the first of three epochs of the Triassic The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago The Holocene is a Geological epoch which began approximately 10000 years ago (about 8000 BC The Fire Salamander ( Salamandra salamandra) is probably the most well-known Salamander species in Europe. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and Ernst Heinrich Philipp August Haeckel ( February 16, 1834 — August 9, 1919)also written von Haeckel, was an eminent German This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species Apoda redirects here For the Moth Genus, see Apoda (moth. For the bishop of Carthage see Caecilianus. A class is the Taxonomic rank in the Biological classification of organisms in Biology below phylum and above order. Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and
Extant amphibians fall into one of three orders - the Anura (frogs, including toads), the Caudata or Urodela (salamanders, including newts), and the Gymnophiona or Apoda (the limbless caecilians). This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. A toad can refer to a number of Species of Amphibians in the order Anura. Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species A newt is an Amphibian of the Salamandridae family order Urodela or Caudata, found in North America, Europe, and Apoda redirects here For the Moth Genus, see Apoda (moth. For the bishop of Carthage see Caecilianus. Although the ancestry of each group is controversial, all share certain common characteristics, which indicates they evolved from a common ancestor and so form a clade. A group of organisms is said to have common descent if they have a common Ancestor. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor The publication of a Permian-period stem form Gerobatrachus hottoni showed the frogs and salamanders had a common ancestor more recently (ca 290 Mya) than had been thought by using the molecular clock alone. Gerobatrachus, also referred to as a frogamander is an Extinct Genus of early toothed Amphibian, a stem-batrachian that lived The molecular clock (based on the molecular clock hypothesis ( MCH) is a technique in Molecular evolution to relate the divergence time of two Species
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Relationships and controversy
Whilst the monophyly of the Lissamphibia is accepted by many herpetologists and paleontologists, the origin and relationships of the various Lissamphibian groups both with each other and among other early tetrapods remains controversial. Herpetology (from Greek: ἑρπετόν herpeton, "creeping animal" and λόγος logos, "knowledge" is the branch of Zoology Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals Not all paleontologists are convinced that the lissamphibia are indeed a natural group, as the various characteristics are also shared with some Paleozoic amphibians, and it is still possible that these characteristics evolved independently. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life"
Currently there are three prevailing theories of Lissamphibian origin: monophyletic within the temnospondyli, monophyletic within lepospondyli, and diphyletic (two separate ancestries) with apodans within the lepospondyls and salamanders and frogs within the temnospondyli. Temnospondyli (from Greek τεμνειν temnein = "to cut" + σπονδυλως spondulos = "vertebra" are an important and extremely diverse Lepospondyli are a group of small but diverse Carboniferous to early Permian Amphibians Six different Clades are known the Acherontiscidae In Phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all Apoda redirects here For the Moth Genus, see Apoda (moth. For the bishop of Carthage see Caecilianus. Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating.
Characteristics
The following characteristics are shared by some, most, or all Lissamphibia. Some of these apply to the soft body parts and hence not present in fossils. Those which refer to the skeleton and are fossilisable are also known from several types of Palaeozoic amphibians - most )
- Two types of skin glands (mucous & granular)
- Fat bodies associated with gonads
- Double-channeled sensory papillae in the inner ear
- Green rods (a special type of visual cell, unknown in caecilians)
- Ribs do not encircle body
- Ability to elevate the eye (with levetator bulbi muscle)
- Forced pump respiratory mechanism
- Cylindrical centra (the main body of the vertebra; cylindrical centra are also found in several groups of early tetrapods)
- Pedicellate teeth (the crown of the teeth is separated from the root by a zone of fibrous tissue; also found in some Dissorophoidea; the teeth of some fossil salamanders are not pedicellate)
- Bicuspid teeth (two cusps per tooth, also found in juvenile dissorophoids)
- Operculum (small bone in the skull, linked to shoulder girdle by the opercularis muscle; perhaps involved in hearing and balance; absent in caecilians and some salamanders, fused to the stapes (ear bones) in most anurans)
- Loss of posterior skull bones (also in Microsauria and Dissorophoidea)
- Small, widely separated pterygoids (also found in Temnospondyli and Nectridea)
- Wide cultriform process of the parasphenoid (also found in some Microsauria (Rhynchonchos) and Lysorophia)
- Double or paired occipital condyle
External links
- Biology 356 - Major Features of Vertebrate Evolution by Dr. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water The gonad is the organ that makes Gametes The gonads in males are the Testes and the gonads in Females are the Ovaries. The ear is the sense organ that detects Sounds The Vertebrate ear shows a common biology from Fish to Humans with variations In Vertebrate Anatomy, ribs ( Latin costae) are the long curved Bones which form the ribcage. Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain A vertebra (plural vertebrae) is an individual Irregular bone in the spinal or Vertebral column ( aka ischis a flexuous and flexible column Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals Dissorophoidea are a clade of medium-sized temnospondyl amphibians that appeared during the Late Pennsylvanian in Euramerica, and continued through Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species Dissorophoidea are a clade of medium-sized temnospondyl amphibians that appeared during the Late Pennsylvanian in Euramerica, and continued through The operculum, meaning little lid (plural opercula or operculums is a corneous or Calcareous structure which exists in some groups of marine freshwater and land Microsauria is an extinct Order of lepospondyl Amphibians from the Carboniferous period and survived into early Permian. Dissorophoidea are a clade of medium-sized temnospondyl amphibians that appeared during the Late Pennsylvanian in Euramerica, and continued through Temnospondyli (from Greek τεμνειν temnein = "to cut" + σπονδυλως spondulos = "vertebra" are an important and extremely diverse Nectridea is an extinct order of lepospondyl Amphibians from the Carboniferous period of which the famous Diplocaulus was a member Microsauria is an extinct Order of lepospondyl Amphibians from the Carboniferous period and survived into early Permian. Lysorophia are an order of aquatic Carboniferous and Permian amphibians which resembled small snakes The occipital condyles are undersurface facets of the Occipital bone in vertebrates, which function in articulation with the superior facets of the Robert Reisz, University of Toronto
References
- Benton, M. J. (2005), Vertebrate Paleontology, 3rd ed. Blackwell Science Ltd
- Carroll, RL (1988), Vertebrate Paleontology and Evolution, WH Freeman & Co.
- San Mauro, Diego; Miguel Vences, Marina Alcobendas, Rafael Zardoya and Axel Meyer (May 2005). "Initial diversification of living amphibians predated the breakup of Pangaea". American Naturalist 165: 590-599.
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