Tot to be confused with the massive dinosaur
Bracbiosaurus, which was some 26m/85 fr long,
Brancbiosaurus belonged to the group of tetra pods known
as rernnospondyls. These appeared during the Early to Mid
Carboniferous Period and included newt-like aquatic forms
as well as large, powerful, land-going predators, such as
Eryops (see overleaf) and Mastodonsaurus, which had scaly
or bony plates on the skin and bore a vague outward
resemblance to crocodiles. Brancbiosaurus was a smallish,
fully aquatic form, about 30cm/12in in length, that in
some ways resembled the modern salamander-like axolorl.
It had four weak limbs for walking in water, a long finned
tail for swimming, and feathery external gills. Its family
date from the Late Carboniferous Period through to the
Permian. Usually only the young or larval forms of
amphibians, known commonly as
tadpoles, have external gills.
('Amphibian' is a commonly
used though imprecise term
usually applied to tetra pods that
breathe using gills when young,
and by gills and/or lungs when
adult.) Keeping the larval gills
as the rest of the body became
sexually mature is an example
of a well-known phenomenon in animal
development termed paedomorphosis - retention of juvenile
features into adult life - something that it shares with the
Mexican axolorl. Branchiosaurus' way of life as a sharptoothed
aquatic predator was similar to that of
Micromelerpetoll, opposite