Natural Science Forum / Biology / Paleontology / February 2005

By a wide margin the biggest known monotreme was the giant echidna
*"Zaglossus" hacketti* (probably shouldn't be in the same genus as the
extant *Zaglossus bruijnii* of NG), of Late Pleistocene Mammoth Cave
deposits (Southwestern WA) - over 1 metre long. How it made a living is
anyone's guess since we don't have a skull and the two extant echidna
species live very different lifestyles (one eats ants, the other eats
worms)

Incidentally the living long-beaked echidna (Z. bruijnii) is one of the
coolest animals on the planet in that the male has up to 4 terminal
papillae on his penis - imagine walking around with a gatling gun in
your pants!!!

Er...as for radically different lifestyles - every known pre-Pliocene
monotreme had fully formed adult molars and sometimes premolars so they
obviously tackled their food a lot differently than their modern
toothless cousins (and were probably less specialised in their choice of
prey as well).

And of course theres *Kollikodon ritchiei* (theres a bit of debate
regarding its monotreme classification) with those incredible "hot-cross
bun" teeth that were obvious meant to pulverise something very hard.

As for bills - the toothed platypodes Monotrematum (Paleocene S.Am) and
Obdurodon (Oligo-Miocene Oz) obviously had them. Anything earlier is
only known from jaw fragments. Large canals on the mandibles of the
Cretaceous Kollikodon and Steropodon is consistent with these forms
being billed as well.

Cheers
Brian