The vertebrate integument arose about 450 million years ago as an 'armour' of dermal bony plates in small, jawless fish-like creatures, informally known as the ostracoderms. The Vertebrate Integument, Volume 1 reviews the major changes that have occurred in the vertebrate integument from its beginnings to the present day. Critical questions concerning the origin, structure and functional biology of the bony integument are discussed and intrinsically linked to major steps in vertebrate evolution and phylogeny-the origin of jaws and the origin of teeth. The discussions include the origins of mineralization of major vertebrate skeletal components such as the dermatocranium, branchial arches and vertebral column.
The advances that led to the origin of modern fishes and their phylogenetic development are reviewed and include the evolution of fins and replacement of the bony plates with several types of dermal scales. The evolution of reptiles saw a major transformation of the integument, with the epidermis becoming the protective outermost layer, from which the scales arose, while the dermis lay below it. The biological significance of the newly-evolved beta-keratin in reptilian scales, among the toughest natural materials known, is discussed in the context of its major contribution to the great success of reptiles and to the evolution of feathers and avian flight.
The dermis in many vertebrates is strengthened by layers of oppositely oriented cross-fibres, now firmly entrenched as a design principle of biomechanics. Throughout The Vertebrate Integument, Volume 1 conventional ideas are discussed and a number of new hypotheses are presented in light of the latest developments. The long evolutionary history of vertebrates indicates that the significance of the Darwinian concept of "survival of the fittest" may be overstated, including in our own mammalian origins and that chance often plays a major role in evolutionary patterns. Extensive illustrations are included to support the verbal descriptions.
Life in Water
- The first jawless fishes. Evolution of dermal scales
- Bony fishes. A primitive skin covered by dermal scales of various shapes and size
- Cartilaginous fishes. Sharks and allies. Dermal denticles (placoid scales), reduces drag
Transition to Life on Land
- The Integument as a Selective Barrier
- Early reptiles and the origin of reptilian scales (epidermal).Mammal-like reptiles
- Origin of mammals
- Origin of hair
Return to the sea
- Ichthyosaur, placodonts, nothosaurs, plesiosaurs, mosasaurs
- Evolution of high-speed aquatic locomotion in ichthyosaurs
- The skin of ichthyosaurs compared with that of other modern high-speed, thunniform swimmers, tuna, dolphins and lamnid sharks
- The Dinosaurs.The big, the bad and the beautiful
- Ornamentation and defense-horns, crests and frills
- Archaeopteryx, the first bird
- Origin of Birds
- Origin of the feather.The Modern Vertebrate Skin
- Adaptation to life in the air
- Structure and function of the modern feather.
Nature's Dominant Structural Biomaterials
- KeratinDeath, Decay and Fossilization
- How animals decompose
- Slowing down the decay process in nature
- Soft tissue - biological to geological preservation
Professor Theagarten Lingham-Soliar works at the Nelson Mandela Metropolitan University, Port Elizabeth and is an Honorary Professor of Life Sciences at the University of KwaZulu-Natal.