The Collaborative International Dictionary of English v.0.48:

Testudinate \Tes*tu"di*nate\, Testudinated \Tes*tu"di*na`ted\,
   a. [L. testudinatus, fr. testudo, -inis, a tortoise, an arch
   or vault.]
   Resembling a tortoise shell in appearance or structure;
   roofed; arched; vaulted.
   [1913 Webster]