Count: 0 — No amphibian species were found that meet the criteria of having an English common name beginning with the letter X. A review of authoritative taxonomic resources (AmphibiaWeb, IUCN Red List, Amphibian Species of the World) returns no accepted, well-documented species whose common name starts with X. Interesting detail: the letter X does appear in scientific genus names (for example, Xenopus for African clawed frogs), but common English names for those animals begin with other words such as “African” or “clawed,” so they do not qualify under a strict “starts with X” rule.

Note the reason for the empty result is linguistic and taxonomic. English common names rarely begin with X, and taxonomists tend to use Latin or Greek roots for genus names where X appears as a prefix (xeno-, xeno- derivatives), not for widely used English names. Also, many historical or obscure genus names that begin with X have been reclassified or treated as synonyms, and the criterion here excludes doubtful or synonymized records. If a close match is acceptable, check amphibian genera that start with X (for example Xenopus) or search for species whose scientific genus starts with X; otherwise, broaden the query to “amphibians with X in the name” or to related letters, and consult AmphibiaWeb, IUCN, or Amphibian Species of the World for verified names, habitats, and lifespan data.