ضفدع ثعباني

ضفدع ثعباني
Caecilians
Temporal range: 170–0 Ma
Lower Jurassic – Recent[1]
Dermophis mexicanus.jpg
Dermophis mexicanus
التصنيف العلمي
مملكة:
Phylum:
Class:
Order:
Gymnophiona

مولر، 1832
الفصائل

Rhinatrematidae
Ichthyophiidae
Uraeotyphlidae
Scolecomorphidae
Typhlonectidae
Caeciliidae

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توزيع الضفادع الثعبانية (بالأخضر)

ضفدع ثعباني (إنگليزية: caecilians، /sˈsɪliənz/) هي رتبة Gymnophiona من البرمائيات التي تشبه ظاهرياً ديدان الأرض أو الثعابين. ويعيشوا في الغالب مختفين في الأرض، مما يجعلهم أكثر البرمائيات غموضاً. كل الضفادع الثعبانية المتواجدة وأقرب أقربائهم أحفورياً يجتمعون في clade Apoda. وينتشرون في الغالب في مداريات أمريكا الجنوبية وأفريقيا وجنوب آسيا. وجبة الضفدع الثعباني غير معروفة على وجه الدقة.

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التصنيف العلمي

The most recent classification of caecilians divides the Gymnophiona into 9 families.[2] This classification is based on a thorough definition of monophyla based on the most recent morphological and molecular evidence, and it solves the longstanding problems of paraphyly of the Caeciliidae in previous classifications without an exclusive reliance upon synonymy.[3]


التطور

Eocaecilia, the earliest known caecilian

Little is known of the evolutionary history of the caecilians, which have left a sparse fossil record. The first fossil, a vertebra dated to the Paleocene, was not discovered until 1972.[4] The putative earliest fossil known comes from the Jurassic period; its primitive genus, Eocaecilia, had small limbs and well-developed eyes.[5] In their 2008 description of the fossil batrachian Gerobatrachus[6] Anderson and co-authors suggested that caecilians arose from the Lepospondyl group of ancestral tetrapods, and may be more closely related to amniotes than to frogs and salamanders, which arose from Temnospondyl ancestors. Divergent origins of caecilians and other living amphibians may help explain the slight discrepancy between fossil dates for the origins of modern amphibia, which suggest Permian origins, and the earlier dates, in the Carboniferous, predicted by molecular clock studies of DNA sequences. Most morphological and molecular studies of living amphibians, however, support monophyly for caecilians, frogs, and salamanders, and the most recent molecular study based on multi-locus data suggest a Late Carboniferous–Early Permian origin of living amphibians.[7]

السلوك

التكاثر

Maternal care in Ichthyophis

انظر أيضاً

الهامش

Specific references:

  1. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة EoR
  2. ^ Wilkinson, M. (2011). "A nine-family classification of caecilians (Amphibia: Gymnophiona)". Zootaxa (2874): 41–64. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  3. ^ Frost, Darrel R.; Grant, Taran; Faivovich, Julián; Bain, Raoul H.; Haas, Alexander; Haddad, Célio F.B.; De Sá, Rafael O.; Channing, Alan; Wilkinson, Mark (2006). "The Amphibian Tree of Life". Bulletin of the American Museum of Natural History. 297: 1–370, appendices. doi:10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2. ISSN 0003-0090.
  4. ^ Estes, Richard (22 September 1972). "The First Fossil Record of Caecilian Amphibians". Nature. 239 (5369): 228. doi:10.1038/239228b0. Retrieved 18 August 2009. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  5. ^ Jenkins, Parish A. (16 September 1993). "An Early Jurassic caecilian with limbs". Nature. 365 (6443): 246. doi:10.1038/365246a0. Retrieved August 18, 2008. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  6. ^ Anderson, Jason S.; Reisz, Robert R.; Scott, Diane; Fröbisch, Nadia B.; Sumida, Stuart S. (2008). "A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders". Nature. 453 (7194): 515–8. doi:10.1038/nature06865. PMID 18497824.
  7. ^ San Mauro, D. (2010). "A multilocus timescale for the origin of extant amphibians". Molecular Phylogenetics and Evolution. 56 (2): 554–561. doi:10.1016/j.ympev.2010.04.019. PMID 20399871.

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