REPTILES
REPTILES
Testudines 341 species
Turtles: Testudines
Joyce et al. 2004
Pleurodira
Testudines
Cryptodira
Turtle synapomorphies
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Limb girdles internal to rib cage
Lack teeth
Loss/fusion of skull bones
Anapsid skull
Shell
– dorsal carapace
– ventral plastron
Turtle shell
• Carapace (dorsal shell)
– Composed of 55-60 bones
• Fused to ribs
• Fused to vertebrae
• Plastron (ventral shell)
– Composed of 9 bones
• Bones covered by epidermal "scales"
Life with a shell
• Protection from predators
• Constrained morphology
– Affects physiology, ecology, selective response
• Shell shape often reflects ecology
("ecomorphology")
– Terrestrial: domed
– Aquatic: flattened, streamlined
• Storage of calcium
• Breathing adaptations
Turtle respiration
• Ribs (shell) are rigid, so can't use costal muscles to breathe like other
vertebrates
• Lungs are dorsal, attached to carapace
• Sheets of muscle attach internal organs to shell
– One set of muscles pulls internal organs distally in body cavity
(inspiration)
– Other set pulls organs inwards and upwards towards lungs, forcing
air out
• Some cutaneous, buccal respiration
• Cloacal breathing
1. Premaxilla 2. Prefrontal 3. Frontal 4.
Postorbital 5. Parietal 6. Squamosal 7.
Supraoccipital
1. Premaxilla 2. Maxilla 3. Vomer 4. Palatine 5.
Zygomatic (jugal) 6. Postorbital 7.
Quadratojugal 8. Quadrate 9. Squamosal 10.
Supraoccipital 11.Parietal
Turtle Life History
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Carnivorous, Omnivorous, or Herbivorous
Generally long-lived
Internal fertilization
All species oviparous
– Nest in soil or sand
• Temperature dependent
sex determination
• No parental care
Variation in turtles
• Skull structure
• Aquatic, terrestrial traits
– Limbs
– Shell
• Shell structure
– Plastron hinged/rigid
– Carapace
• Shape, extent
• Skin
• Omnivore/carnivore/
herbivore
Chelidae: Chelus fimbriatus
11 genera, 54 spp
Pelomedusidae: Pelomedusa subrufa
2 genera, 19 spp
Chelydridae: Chelydra serpentina
2 genera/spp
Emydidae:
Terrapene carolina
Emydidae:
Trachemys scripta
12 genera, 50 spp
Chelonidae:
Chelonia mydas
5 genera, 6 spp
Testudinidae:
Gopherus berlandieri
11 genera, 58 spp
Trionychidae:
Apalone spinifera
14 genera, 30 spp
Kinosternidae:
Kinosternon flavescens
3 genera, 25 spp
– Morphology; parsimony
• Shaffer et al. (1997)
– mtDNA, morphology; parsimony
Cryptodira
• Gaffney and Meylan (1988)
Pleurodira
Turtle phylogeny
• Fujita et al. (2004)
– nDNA; likelihood
• Krenz et al. (2005)
– mtDNA, nDNA; parsimony, likelihood, Bayesian
• 2010
– Thomson and Shaffer (50 kb nDNA, mtDNA; parsimony; 'sparse supermatrix')
– Barley et al. (10+ kb nDNA, mtDNA; likelihood, Bayesian)
– Sterli (morphology, nDNA, mtDNA, fossil taxa; parsimony)
• 2015
– Crawford et al.
Barley et al.
Barley et al.