Kolkata: A scientific mystery dating back to the 19th century has finally been solved by researchers at the Zoological Survey of India (ZSI).ZSI scientists Sumidh Ray and Pratyush P Mohapatra have resolved long-standing confusion surrounding the identity of a desert lizard first described over 150 years ago by renowned Austro-Hungarian naturalist Ferdinand Stoliczka. The Persian long-tailed desert lizard (Mesalina watsonana), was originally described in 1872 from the Sindh region—now in modern-day Pakistan.Over the years, scientists were confounded by conflicting records and scattered type specimens, or syntypes, held in museums in Kolkata, London and Vienna. Without a single designated "name-bearing" specimen, the species' identity remained shrouded in ambiguity.Ray and Mohapatra designated a single specimen—ZSI-R-5050, housed in the ZSI's Kolkata collection—as the official lectotype. This designation provides a clear and permanent reference point for the species' identity. "This clarification is vital not just for taxonomy, but for ongoing research into desert lizard diversity across South and Central Asia," said Dhriti Banerjee, director of the ZSI."Stoliczka's collections are foundational to our understanding of regional herpetofauna, and this designation honours his enduring legacy." The findings, published in the peer-reviewed journal Zootaxa, are expected to support future research on species complexes within Mesalina and highlight the role of preserving and reassessing museum collections.