Bradytelic

A distinction is to be made between slow horotelic rates and bradytelic rates, also slow but essentially a different phenomenon, as demonstrated by the marked difference in survivorship pattern, from which the existence of bradytelic rates have been deduced.

This low-rate, nonnhorotelic excess is bradytely and the rates involved in it are bradytelic.

Bradytelic — when organisms evolve at exceptionally slow rate. It is believed that this classification applies to plants also. Many annual species like Gilia, Clarkia, and many epiphytic orchids are tachytelic while Magnolia, Cer- cidiphyllum, ...

For example, bradytelic lines — defined by Simpson (1953:113) as "low rates" or "arrested evolution" — imply, above all, extremely low rates of morphological evolution over a considerable span of time — usually at least 100 million years.

Slow bradytelic evolvers are famous as living fossils. Good examples are horseshoe crabs, coelacanth fish, crocodiles, opossums, and primitive lampshells (linguloid brachiopods). Simpson pegged these as bradytelic because they belong to ...