The Syrian brush-tailed mouse <i>Calomyscus tsolovi</i> Peshev, 1991, a species known exclusively from the original type series

Abstract The Syrian brush-tailed mouse Calomyscus tsolovi Peshev, 1991, known only from a small hypodigm obtained in southern Syria in 1982, has not been recorded since its original discovery. The species may represent one of the most enigmatic small mammals in the Middle East. Here, we summarize all available information on C. tsolovi , discuss possible causes for its excessive rarity, and highlight the urgent need for targeted field surveys to verify its continued existence.