A draft by Heckel of the drawing of a specimen (a possible syntype) Idus melanotus, representing a fish collected in the Danube in May 1841 (NHMW Archive).

 
 
  Part of: Palandačić A, Chai MJ, Shandikov GA, Akkari N, Frade PR, Randolf S, Berg H-M, Mikschi E, Bogutskaya NG (2024) An annotated catalogue of selected historical type specimens, including genetic data, housed in the Natural History Museum Vienna. ZooKeys 1203: 253-323. https://doi.org/10.3897/zookeys.1203.117699