Testudinata (turtles) Flashcards
What is the distribution of turtles? Are they land or water dwelling?
They are in the northern hemisphere, and they can be aquatic, semi-aquatic, and terrestrial, they are omnivorous
What is reproduction like for Testudines? (reproduction, eggs?, parental care, sex determination)
They use internal fertilization through and intromittent organ (true penis), all species are oviparous with little to no parental care, they lay either hard or leathery shelled eggs and their sex is determines by the temperature of incubation
What are the diagnostic features of Testudinata? (7)
Modified ribcage into a shell
Anatomy of the shell: have a carapace and plastron and they are joined by bridges at the sides, constituted by bones overlain by keratinous scutes, and the pectoral/pelvic girdles are contained within the shell
Function of the shell: protection, good because it is rigid/strong with many elements joined tightly together, BUT heavy and some vertebrae and muscles are lost
Anapsid skull, bite force is enhanced by muscle attachment on the emarginations on the back of the skull, toothless and have keratinized beak for feeding
LONG lifespan
How do testudines respirate? What are their two methods of ventilation?
They ventilate air in and out of their respiratory organ by difference in pressure, and costal ventilation is not possible
1. Via contraction of the belly muscles (transversus abdominous)
2. Movement of the limbs during locomotion
What are the two large clades within Testudinata and what separates them?
Pleurodira: neck is folded horizontally Cryptodira: neck can fold into vertical S-bend and can retract head into shell
What are some diagnostic features of Pleurodira? (4)
Neck bent horizontally, jaw closing mechanism involves the pterygoid bone, and have a number of keratinous scutes and a detailed morphology of the plastron
What are some diagnostic features of Cryptodira and what 5 clades are contained within it?
Neck folded into vertical S-bend, head can be fully retracted into the shell, jaw closing mechanism involved the quadrate, have a number of keratinous scutes and detailed morphology of the plastron
Emydidae, Cheloniidae, Trionychidae, Chelydridae, Testudinidae
What are some diagnostic features of Trionychidae? (6)
Carnivorous, long/pointy snout, depressed carapace, shells lack keratinous scutes, reduced bony shell, 3 digits on forelimb with claws
What are some diagnostic features of Emydidae? (4)
Omnivorous, reduced zygomatic arch, carapace with well-developed rib heads, number and topological relationship of keratinized scutes and bony elements
What are some diagnostic features of Chelydridae? (5) How many species are there?
Depressed carapace with ridges, 5 species contained here, freshwater and aggressive, large head, reduced plastron with long tail, INVASIVE AND DANGEROUS
What are some features of Testudinidae? (8)
Terrestrial, herbivorous, can be small or large, high-domed carapace, stout/columnar legs with reduced digits, forelimbs are covered by thick epidermal scales, head/limbs/tails can be fully retracted into the shell, high tolerance to drought/hunger
What are some features of Cheloniidae? (7) How many species/genera?
Worldwide distribution, mating in the water and eggs are laid on land, large body size, limbs modified into flippers, head and neck are not retractable, depressed carapace (sometimes with keel), bony shell reduced
6 species in 5 genera
What are some features of the Leatherback Turtle, Dermochelys coriacea?
Not member of Cheloniidae but is related to them, shell is reduced to small bony plates with ridges (sometimes) and the shell is covered in a leathery skin that is well developed
