testudinal（adj.）
1823, "pertaining to or resembling a tortoise," from Latin testudo "a tortoise, tortoise shell," from testa "shell" (see test (n.)).
Other adjectives in English included testudineal, testudinate, testudinarious (1826, "resembling a tortoise shell in color"). The classical Latin adjective was testudineus, and English took testudineous in 1650s in both its senses: "resembling the shell of a tortoise" and "as slow as a tortoise."
Compare also Middle English testude "hard swelling on the skin" of the head especially, suggestive of a shell (c. 1400), testudinary.
该词起源时间：1823年