We don't have synonyms for pygal yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are pyral, pagal and zygal.
(adj) :
(anatomy) Situated in the region of the rump, or posterior end of the backbone; applied especially to the posterior median plates in the carapace of chelonians.
(n) :
(anatomy) The posterior median or supracaudal plate of a chelonian carapace.
(adj) :
(anatomy) Situated in the region of the rump, or posterior end of the backbone; applied especially to the posterior median plates in the carapace of chelonians.
(n) :
(anatomy) The posterior median or supracaudal plate of a chelonian carapace.