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Download There`s something wrong with his medulla oblongata
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Conservation and Ecology of Marine Reptiles MARE 494 Dr. Turner Summer 2007 Body Plan Dermochelyids – streamlined body, tapers at shoulders Long clawless fore limbs 5 dorsal ridges run length of carapace Cheloniids – shells composed of bone overlaid by keratinous scutes Margins of scutes don’t align with bony sutures Shell reduced compared with other turtles Scutes & Scales Scutes – keratinous plates found on the shell Scales – thickened areas of epidermis & keratin that cover the skin & head Provide taxonomic information & act as landmarks for describing body location Scutes & Scales Carapace – dorsal surface of the shell Plastron – ventral surface of the shell Scutes & Scales Dermocheyids – possess small scales on throat & shell as hatchlings – are shed No scutes Cheloniids – keratinaceous scutes covering skeletal shell Number & arrangement are species-specific Designated by position & number Scutes & Scales Scutes & Scales Scutes & Scales Scutes & Scales Dermocheyids – characterized by a leathery shell covering a mosaic of thin body plates Deep to the body plates is a layer of dense fibrous tissue & fat Cheloniids – bony shell with distinctive scutes – form similar among species No blubber layer Carapace Carapace Heads & Beaks Dermocheyids – covered with smooth skin hatchlings – small scales on face & throat Cheloniids – large scales covering dorsal and lateral head Neck & throat covered in moderately keratinized skin Heads & Beaks Heads & Beaks Heads & Beaks Rhamphotheci – keratinous beaks of the upper & lower jaws in cheloniids Form differs with diet and can be used to identify species Dermochelyids – lack a distinctive rhamphotheca on either jaw Skin of jaws more heavily keratinized than other pasts of the body Heads & Beaks Skeletal Anatomy Forelimbs of all species are elongated as wing-like flippers Exhibit hyperphalangy – lengthening of the phalanges; shortening, flattening, & fusing of the radius & ulna Hindlimbs – less elongated and more paddle-like in form Appendicular Skeleton Claws – same on fore & hindlimbs Chelonia & adult Natator – 1 claw on each foot Remaining Cheloniids – 2 claws on each foot Skeletal Anatomy Forelimbs - of all species are elongated as wing-like flippers - humerous, radius, ulna, carpals, metacarpals, phalanges - functionally fused by connective tissue Hindlimbs – less elongated and more paddle-like in form - flattened to rudder-like structure Skeletal Anatomy Exhibit hyperphalangy – lengthening of the phalanges; shortening, flattening, & fusing of the radius & ulna Similar in other marine adapted species? Appendicular Skeleton Appendicular Skeleton The Skull Skull shape plus the form & patterns of bones on the roof of the mouth are diagnostic for species identification The Skull Skull shape plus the form & patterns of bones on the roof of the mouth are diagnostic for species identification The Skull Leatherback – wide posterior, rounded anteriorly; large orbits, no parietal notches - loosely articulated bones Cheloniid – partial secondary palate - tightly articulated bones The Skull Loggerhead Green Kemp’s Ridley Hawksbill Olive Ridley Leatherback The Skull Green – rounded, short snout, shallow parietal notch Loggerhead, Ridleys & Flatback – large, wide posteriorly, tapers anteriorly to orbits, wide parietal notches Hawksbill – long & narrow (L 2x W), snout tapers to point, deep parietal notches Head & Neck Musculature Head & Neck Musculature Muscle actions in marine turtles: Flexion – bending parts of a joint Extension – straightening of those parts Protraction – moving outward & forward Retraction – moving inward & backward Head & Neck Musculature Muscle actions in marine turtles: Abduction – moving away from plastron Adduction – moving toward plastron Rotation – turns about its axis Depression – opens the jaws (abduction) Elevation – closes the jaws (adduction) Brains! Central nervous system Brain – fore, mid, hind Forebrain – posterior cerebrum Midbrain – eye to posterior aspect of optic lobe Hindbrain – ear to posterior cerebellum Brains! “There’s something wrong with his medulla oblongata...” - Colonel Sanders Cerebrum- region of the brain that regulates language & communication, movement, olfaction, memory, and emotion Cerebellum – region of the brain that plays an important role in the integration of sensory perception and motor output Brains! “Well, folks, Mama's wrong again.” - Colonel Sanders Medulla oblongata – region of the brain to control autonomic functions (breathing & heartbeat), relay nerve messages, processing of inter-aural time differences for sound localization Olfactory bulb – very old part of the brain; processes smell Optic lobe - part of the brain where vision is processed; the optic nerves partially cross Brains! Brains! “To enter, send me your parents' brains. Or write "Parents‘ brains" on a three by five card, and send it to... – Zombie Krusty Specific landmarks identifying locations of the parts of the brain differ slightly among Cheloniids; greatly from Dermochelys - leatherback brain housed deeply; pineal organ extends dorsally in cartilaginous cone - used for light detection Brains! “Braaaaains... Use your brains to help us! Your delicious braaaains...” –Homer Simpson
