1 / 27

Skeleton, Skin and Scales

Skeleton, Skin and Scales. evolutionary time. High # bones. Low # bones. Skull. Evolutionary tendency. Fusion of skull bones. Neurocranium (brain case) Branchiocranium (endoskeletal arches, original gill arch supports). Chondrocranium (original cartilagenous braincase)

breanna
Download Presentation

Skeleton, Skin and Scales

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Skeleton, Skin and Scales

  2. evolutionary time High # bones Low # bones Skull Evolutionary tendency Fusion of skull bones

  3. Neurocranium(brain case) Branchiocranium (endoskeletal arches, original gill arch supports) Chondrocranium(original cartilagenous braincase) Dermatocranium (dermal bones attached to skull) Arches: Mandibular Palatine Hyoid Opercular Branchial Skull

  4. Neurocranium

  5. Branchiocranium

  6. Branchiocranium • Mandibular Arch (cartil. & dermal origin) • Sharks • Palatoquadrate Cartilage (top jaw) • Meckel´s Cartilage (bottom jaw) • Bony Fishes • Premaxillae, Maxillae, Supramaxillae (top jaw) • Dentary, Angular (bottom jaw) • Palatine Arch (cartil. origin)

  7. Branchiocranium • Hyoid Arch or Supensorium (cartil. Orig.) • Provides support and attachment to skull. • lower jaw (Quadrate) • opercular apparatus • Opercular Arch (dermal origin) • Protects gills (Opercule)

  8. Branchiocranium • Branchial Arches (cartil. origin) • Support gills (Ceratobranchial & Epibranchial) • Help chewing (Pharingeal bones)

  9. Lampreys

  10. Sharks

  11. Bony Fishes

  12. Jaw evolution hypothesis

  13. Viperfish mandible

  14. Protrusible mouth (ascending process on premaxilla that slides along front of skull). premaxilla maxilla mandible

  15. HYOSTYLIC AMPHISTYLIC AUTOSTYLIC Jaw Suspension Evolution

  16. Vertebral Column Precaudal Caudal

  17. Fins • Pectoral Girdle • Not attached to vertebral column • Attached to Skull • Pelvic Girdle • Not attached to vertebral column • Caudal Fin • Protocercal, heterocercal, homocercal

  18. Fins • Median Fins • Sharks • Ceratotrichia (dermal) • Radials (cartil.)

  19. Fins • Median Fins • Bony Fishes • Ceratotrichia (in larval stages) • Lepidotrichia (dermal) • Pterygiophores (cartil.)

  20. Soft rays True Spines soft segmented branched bilateral hard and pointed unsegmented unbranched solid

  21. Skin

  22. Scale Types • Placoid • Sharks, rays and chimaeras • dermal and epidermal origin • Irrigated pulp cavity + dentine + vitrodentine • homologous to vertebrate teeth • Cosmoid • Lungfishes • originated by fusion of placoid scales • Two bone layers + cosmine + vitrodentine

  23. Scales • Ganoid • Sturgeons, paddlefish and gars • modified cosmoid scale • Two bone layers + dentine + ganoine • Cycloid and Ctenoid • Bony fishes • evolved from ganoid scale (loss of ganoine) • Almost all dermal • Overlapping (shingle-like)

  24. Scales

  25. PLACOID COSMOID GANOID

  26. CYCLOID CTENOID

More Related