Regional Morphology

This is relevant for Pit Vipers in South America and the West Indies.

Morphological identification key

Crotalinae

Is there a "rattle" or a knob-like projection on the end of the tail?	yes	Crotalus durissus ssp.


no

Are there protruding, spiky scales underneath the tip of the tail?	yes	Lachesis sp.


no

Are all or at least some of the subcaudal scales (underneath the tail, from behind the anal plate A, which covers the cloaca) divided?	yes	Bothrops spp. or Bothriopsis spp. (in some cases also Porthidium hyoprora)


no

Bothriechis spp. or Porthidium spp. (P. hyoprora also has divided subcaudal scales in some cases)