conservation and ecology of marine reptiles mare 494 dr. turner summer 2007
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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 - PowerPoint PPT PresentationTRANSCRIPT
Conservation and Ecology of Marine Reptiles
MARE 494Dr. Turner
Summer 2007
Body PlanDermochelyids – streamlined body, tapers at shouldersLong clawless fore limbs5 dorsal ridges run length of carapace
Cheloniids – shells composed of bone overlaid by keratinous scutesMargins of scutes don’t align with bony suturesShell reduced compared with other turtles
Scutes & ScalesScutes – 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 & ScalesCarapace – dorsal surface of the shell
Plastron – ventral surface of the shell
Scutes & ScalesDermocheyids – possess small scales on throat & shell as hatchlings – are shedNo scutes
Cheloniids – keratinaceous scutes covering skeletal shellNumber & arrangement are species-specific
Designated by position & number
Scutes & Scales
Scutes & Scales
Scutes & Scales
Scutes & ScalesDermocheyids – characterized by a leathery shell covering a mosaic of thin body platesDeep to the body plates is a layer of dense fibrous tissue & fat
Cheloniids – bony shell with distinctive scutes – form similar among speciesNo blubber layer
Carapace
Carapace
Heads & BeaksDermocheyids – covered with smooth skin hatchlings – small scales on face & throat
Cheloniids – large scales covering dorsal and lateral headNeck & throat covered in moderately keratinized skin
Heads & Beaks
Heads & Beaks
Heads & BeaksRhamphotheci – 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 jawSkin of jaws more heavily keratinized than other pasts of the body
Heads & Beaks
Skeletal AnatomyForelimbs 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 SkeletonClaws – same on fore & hindlimbs
Chelonia & adult Natator – 1 claw on each foot
Remaining Cheloniids – 2 claws on each foot
Skeletal AnatomyForelimbs - 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 AnatomyExhibit hyperphalangy – lengthening of the phalanges; shortening, flattening, & fusing of the radius & ulna
Similar in other marine adapted species?
Appendicular Skeleton
Appendicular Skeleton
The SkullSkull shape plus the form & patterns of bones on the roof of the mouth are diagnostic for species identification
The SkullSkull shape plus the form & patterns of bones on the roof of the mouth are diagnostic for species identification
The SkullLeatherback – wide posterior, rounded anteriorly; large orbits, no parietal notches - loosely articulated bones
Cheloniid – partial secondary palate - tightly articulated bones
LoggerheadKemp’s Ridley Olive Ridley
Green Hawksbill Leatherback
The Skull
The SkullGreen – 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 MusculatureMuscle actions in marine turtles:Flexion – bending parts of a jointExtension – straightening of those parts
Protraction – moving outward & forwardRetraction – moving inward & backward
Head & Neck MusculatureMuscle actions in marine turtles:Abduction – moving away from plastronAdduction – 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!
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
“There’s something wrong with his medulla oblongata...” - Colonel Sanders
Brains!
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
“Well, folks, Mama's wrong again.” - Colonel Sanders
Brains!
Brains!
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
“To enter, send me your parents' brains. Or write "Parents‘ brains" on a three by five card, and send it to... – Zombie Krusty
Brains!“Braaaaains... Use your brains to help us! Your delicious braaaains...” –Homer Simpson