Gymnophiona

Report
BIOL 3300 Vertebrate Zoology: Ectotherms Herpetology
http://www.amphibian.com.au/
Caecilians – Chpt. 15
What is a caecilian?
• Key anatomical features?
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•
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• Which are derived
characters?
What is a caecilian?
• Key anatomical features?
•
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Epicrionops bicolor – Digimorph.org
Ichthyophis bannanicus – Digimorph.org
Dermophis mexicanus – Digimorph.org
Figure 15.1 The unique dual jaw-closing mechanism present in all four major clades of caecilians consists of the mechanism ancestral in vertebrates, the masseter
adductor mandibulae, a muscle that pulls up on the lower jaw, and a new mechanism, the masseter interhyoideus posterior, which pulls down on the processus
retroarticularis (pret) an extension of the dentary bone. The result is that the lower jaw swings up. This mechanism is progressively more developed in more derived
caecilian clades. Redrawn from Nussbaum, 1983.
How many caecilians?
• ~
species
•
genera
•
families
• Phylogenetic
problems?!?
Figure 15.2 A cladogram depicting relationships among the families of extant caecilians. Based on Wilkinson and Nussbaum, 2006.
Natural history of caecilians?
• In what habitats do they live?
• What about reproduction?
See Life in Cold Blood clip
• Diet?
What is the geographic
distribution of caecilians?
Figure 15.3 Geographic distribution of the extant Caeciliidae.
Features of Caeciliidae
(Tailless Caecilians)
• Primary annuli… some 2°… _____
•
• Stapes present
Features of Caeciliidae
(Tailless Caecilians)
• Largest family
(>___species)
•
• 100mm – 1,500mm
•
• Can occur in
disturbed/agricultural
grounds…
friable-pesticides!
What is the geographic
distribution of caecilians?
Figure 15.5 Geographic distributions of the extant Ichthyophiidae and Rhinatrematidae.
Features of Ichthyophiidae
(Asian Tailed Caecilians)
• 1°… 2°… AND 3° annuli
•
• Stapes present
http://en.wikipedia.org/wiki/Ichthyophiidae
Features of Ichthyophiidae
(Asian Tailed Caecilians)
• 2nd largest family (~50)
•
• Size up to ~500mm
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•
What is the geographic
distribution of caecilians?
Figure 15.6 Geographic distributions of the extant Typhlonectidae, Scolecomorphidae, and Uraeotyphlidae.
Features of Typhlonectidae
(Aquatic Caecilians)
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•
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• Stapes present
Features of Typhlonectidae
(Aquatic Caecilians)
• 3rd largest family (~10)
• Size up to ~750mm
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•
What is the geographic
distribution of caecilians?
Figure 15.5 Geographic distributions of the extant Ichthyophiidae and Rhinatrematidae.
Features of Rhinatrematidae
(American tailed Caecilians)
• 1°… 2°… AND 3° annuli; with numerous dermal
scales
• ______________ with skeletal, muscular and
integumentary units
• Stapes present
Epicrionops bicolor
http://zoologia.puce.edu.ec
What is the geographic
distribution of caecilians?
Figure 15.6 Geographic distributions of the extant Typhlonectidae, Scolecomorphidae, and Uraeotyphlidae.
Features of Scolecomorphidae
(Buried-Eyed Caecilians)
• 1° annuli ONLY
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•
•
• NO stapes present
What is the geographic
distribution of caecilians?
Figure 15.6 Geographic distributions of the extant Typhlonectidae, Scolecomorphidae, and Uraeotyphlidae.
Features of Uraeotyphlidae
(Kerala Caecilians)
• 1° & 2° annuli, but ________________
• Dermal scales present
•
• Stapes present
Gegeneophis primus, the new species of caecilian amphibian reported from Kerala.
http://www.thehindu.com
Figure 15.4 Representative caecilians. Clockwise from upper left: Sao Tome caecilian Schistometopum thomense, Caeciliidae (R. A. Nussbaum); monarch tailed caecilian
Ichthyophis monarchus, Ichthyophiidae (L. L. Grismer); Bannan caecilian Ichthyophis bannanicus, Rhinatrematidae (E. D. Brodie, Jr.); African buried-eyed caecilian
Scolecomorphus vittatus, Scolecomorphidae (L. W. Porras).
Figure 15.7 Representative caecilians. From left: Water caecilian Typhlonectes natans, Typhlonectidae; Kannan caecilian Uraeotyphlus cf. narayana, Uraeotyphlidae (D.
J. Gower, The Natural History Museum, London).

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