matamata

from The Collaborative International Dictionary of English v.0.48

Pleuroderes \Pleu*rod"e*res\, n. pl. [NL., fr. Gr. ? the side +
   ? the neck.] (Zool.)
   A group of fresh-water turtles in which the neck can not be
   retracted, but is bent to one side, for protection. The
   {matamata} is an example.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Matamata \Ma`ta*ma"ta\, n. [Pg.] (Zool.)
   The bearded tortoise ({Chelys fimbriata}) of South American
   rivers.
   [1913 Webster]