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Birgus, a genus of hermit crabs containing only one species: Birgus latro. The coconut crab!
(Image credit: Brocken Inaglory, Wikipedia commons)
Originally named Cancer latro by Linnaeus, the genus name is likely derived from the Latin burgus, meaning a small fort, as named by Leach in 1816. No reason was given for this change in spelling in his work A tabular View of the external Characters of Four Classes of Animals, which Linné arranged under Insecta; with the Distribution of the Genera composing Three of these Classes into Orders, &c. and Descriptions of several New Genera and Species in 1816. Latro, on the other hand, means "robber" as named by Linnaeus (so named for one of its common names: the robber crab).
Birgus does exist in Latin, as the name of an Irish river but given their tropical habitat the connection is unlikely. Personally, I believe this was likely just another little spelling mistake in taxonomy (it is latin, after all) that just became formalised over time. It makes for a fun story though!
