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Morpho-anatomical lexicon


  • Atrium : dorsal heart cavity collecting blood from organs. This cavity is not partitioned in acanthomorphs, whereas it is in two auricles in dipnoans and tetrapods.
  • Brockmann body : or principal islet, large amount of endocrine pancreatic cells. It is a giant langerhans islet, its diameter could be of more than 10 mm in some acanthomorphs.
  • Dermal bone : type of bone formed by the direct ossification of a conjonctive tissue without a cartilaginous predecessor.
  • Enchondral bone : type of bone formed by replacing cartilage during development.The cartilage is partially or entirely destroyed.
  • Foramen magnum : large posterior opening of the neurocranium, through which the medulla enters and exits the skull vault.
  • Gill : respiratory organ where main gas and ionic exchanges between blood and water take place.
  • Gill arch : bony arch supporting gills.
  • Gonad : reproductive gland (ovary or testicle).
  • Hypural : bony vertical plate supporting caudal fin-rays.
  • Lateral line: sensory organ detecting vibrations (movements, sounds …) in the environment.
  • Neurocranium : part of the skull surrounding the cephalic nervous system (= « brain »).
  • Opercle : bony structure protecting the gills.
  • Otolith : intracranial concretion growing daily and recording any event of the life of the animal. It plays an important role in equilibration.
  • Premaxilla : bone of the anterior part of the upper jaw. This bone is mobile in Teleostean fishes.
  • Pterygiophore : bony rod supporting a fin-spine or a fin-ray.
  • Sclerotic : white and hard tissue of the eyeball in vertebrates. In telesoteans, and then acanthomorphs, this tissue can be partially or entirely ossified, see pages dedicated to the skull of tuna and swordfish.
  • Splanchocranium : part of the head skeleton surrounding the anterior portion of the digestive tract
  • Swimbladder: diverticle of the digestive tract, full of gaz . It is involved in the buoyancy, the reception and production of sounds. It is absent in many acanthomorph species (Atlantic mackerel, flatfishes, notothenioids ...). See page "When features vanish in the haze....