Integumentary system – comparative anatomy overview
Amphioxus
Epidermis of simple columnar cells
With cilia on outside as a larva, cuticle covering postlarva
Unicellular glands
Dermis a very thin collagen base for epidermis
Agnathans
Epidermis of stratified epithelium (not necessarily stratified squamous)
With many unicellular glands (cuticle or slime coating)
Cornified (epidermal) teeth
(ancient forms with dermal bone “armor”)
Dermis a thin very tough collagen layer
With melanophores
Chonrichthyes
Epidermis of stratified epithelium
Mostly unicellular glands, few multicellular glands
Chromatophores present in both epidermis and dermis
Dermis of dense fibrous connective tissues denticles (tooth scales), spines, teeth emerge to the surface
Chromatophores present in both dermis and epidermis
Osteichthyes
Epidermis of stratified epithelium
Mostly unicellular glands, some multicllular glands
Slime covering (mucous cuticle)
Dermis of two layers
A loose outer layer and a deeper fibrous layer
Scales of various forms ganoid enamel on dentin and lamellar bone (polypterus) enamel on lamellar bone (bowfin and gar) acellular lamellar bone on fibrous collagen ( most other fish)
Chromatophores

Amphibia
Epidermis of stratified squamous epithelium (keratinized in some)
Mostly multicellular glands with ducts (underlying the surface epithelium)
Scattered large secretory cells in surface epithelium
Chromatophores present in both epidermis and dermis
Capillaries present in deeper epidermis for cutaneous respiration
Dermis either fibrous or of both an outer loose and a deeper fibrous layer
Scales absent except in some caecilians (where they are called osteoderms)
Chromatophores present in both dermis and epidermis
Reptilia
Epidermis of keratinized stratified squamous epithelium
Special keratinized structures
– scales, beaks, nails, spines
Few specialized multicellular glands, no unicellular skin glands
Dermis of fibrous connective tissue
Subsurface dermal scales (osteoderms) present in crocodilians, turtles, and some lizards.
Chromophores present in dermis (not sure about epidermis)
Aves
Epidermis of thin keratinized stratified squamous epithelium
Special keratinized structures
– feathers, scales, beaks, nails
Few specialized multicellular glands ( Uropygeal gland) no unicellular skin glands
Chromophores present in epidermis and dermis
Dermis (loose and dense connective tissue?)
Chromophores present in dermis and epidermis
Arrector pilorum muscles
Highly vascular in places
Mammalia
Epidermis of thick keratinized stratified squamous epithelium
Special keratinized features include hair, nails, claws, horns, hooves, tori, baleen, scales
Numerous multicellular glands
Chromophores present
Dermis a very thick layer made of loose and dense connective tissue
Arrector pili muscles
Dermal bone of antlers and the armor of the armadillo