Kessler, born Karl Friedrich Kessler in East Prussia, became Chair of Zoology at the University of Kyiv in 1842 and built a zoological cabinet at St. Vladimir University, today the Taras Shevchenko National University of Kyiv. In 1858 he traveled with his student Konstantin Jelski to the northwestern coasts of the Black Sea and the western Crimea, returning with a large haul of fish specimens from which he described four new species the following year. One of these was the Crimean shemaya, a small silvery fish he reported as abundant in the Salhir River, the largest river of the Crimean Peninsula, and in the Alma. Kessler noted that the fish was a common sight at the market in Simferopol, where he gathered much of his material and, by his own account, quite sufficient information about the ichthyological conditions of Crimea.

The rediscovery matters because the taxonomy of the Black Sea shemaya species complex remains unsettled. Over the decades, A. mentoides has been treated as a valid species, as a synonym of the Caspian shemaya Alburnus chalcoides, or as a synonym of Alburnus mento. Without type specimens, the name-bearers against which all such decisions must be measured, the species could not be reliably diagnosed. Eschmeyer’s Catalog of Fishes recorded the whereabouts of the types as unknown, and researchers assumed they had been lost. The new survey changes that picture by identifying genuine syntypes in Vienna and by sorting out misleading specimens elsewhere.

The team examined eleven specimens registered as possible syntypes in four institutions: the Natural History Museum in London, the Zoological Institute of the Russian Academy of Sciences in St. Petersburg, the Natural History Museum Vienna, and the Zoological Collection of the University of Vienna. Each lot carried a story of exchange, donation or mislabeling. The London specimens, four small fish registered in 1879 under the number BMNH 1879.11.14.144-147, were acquired through an exchange with St. Petersburg, but their recorded locality is Suchum-Kalé, now Sokhumi on the Black Sea coast of Georgia. These fish therefore cannot be part of Kessler’s syntypes and likely represent another species, the Georgian shemaya Alburnus derjugini.

Four specimens at the Zoological Institute in St. Petersburg, registered as ZIN 3030, were presented in 1860 by the scientists Johann Friedrich von Brandt and Gustav Ferdinand Richard von Radde after their travel to the region. Brandt spent three days in Simferopol and acquired several fish species from the Salhir River. Yet Kessler’s original description gives no indication that he used specimens collected by anyone other than himself, and the researchers found no conclusive evidence that these St. Petersburg fish belong to his type series. They remain labeled as possible syntypes with a question mark, a cautionary reminder of how museum labels can outlive the certainty of their authors.

The Vienna material proved decisive. One specimen, registered as NMW 55510 at the Natural History Museum Vienna, came from the Salhir River and was acquired in 1874, when the renowned curator Franz Steindachner registered about 2000 entries, many of them previously unregistered samples. The label reads Alburnus clupeoides Kessl. (typ.), a typical Steindachner-era notation, and the specimen was identified as A. mentoides by Nina Bogutskaya. Steindachner visited the museum in St. Petersburg in 1874 and likely met Kessler, who headed the zoological department at the University of St. Petersburg, making it plausible that the specimen came directly from Kessler’s large type series. The acquisition sheets for that year are incomplete, but the Salhir locality matches the type locality precisely.

Two further specimens, UVZC VZ6366 and UVZC VZ6367, are held at the Zoological Collection of the University of Vienna. Their original label lists Alburnus mentoides Kessler, the year 1860, Kessler as collector and donator, and the locality as the Salhir River at Simferopol. During that era, Rudolf Kner, one of the most renowned ichthyologists of his time, headed the zoological institute of the University of Vienna and maintained contacts with museums in St. Petersburg. Clear evidence shows that Kessler gave material to Kner, including these very specimens. The researchers also considered and rejected an alternative scenario: Brandt and Radde’s expedition passed through Vienna in 1860, but they traveled without their samples, which had been handed over to a land transportation company in Odessa, and no acquisition entries at the Vienna Hof-Naturalienkabinett record fish from their expedition.

With the genuine syntypes identified, the team designated the larger University of Vienna specimen, UVZC VZ6366, as lectotype under the International Code of Zoological Nomenclature, making it the unique bearer of the name Alburnus mentoides. The specimen measures 128.4 millimeters in standard length and shows the diagnostic features of the species: an upturned mouth with a straight mouth cleft, a long lower jaw, a well-pronounced ventral keel with ten scales along its scaleless portion, eight and a half branched dorsal-fin rays, fourteen and a half branched anal-fin rays, 44 vertebrae, 62 lateral-line scales and 24 gill rakers. The two remaining Vienna syntypes, UVZC VZ6367 and NMW 55510, become paralectotypes. The designation draws on 48 morphometric and 15 meristic indices, including novel cranial, jaw and opercular measurements, providing a comprehensive morphological fingerprint for future comparisons.

The lectotype also sharpens a biological question: how many native shemaya species live on Crimea? As early as 1930, Tseeb documented morphological differences in scale size and head length between populations of the Salhir and the southwestern Chorna River, and Berg and later Pavlov and Tscherbuha reached similar conclusions, noting differences in anal-fin ray counts, lateral-line scales, body depth and predorsal distance. The rivers of Crimea belong to separate hydrological zones: the Alma, Belbek and Chorna flow westward into the Black Sea basin, while the Salhir flows northeast into the Sea of Azov. The researchers suggest that two taxa may occur on the peninsula, A. mentoides in the northeastern rivers and an undescribed Alburnus species in the southwest. Notably, no native Alburnus has ever been reliably reported from the Kacha River between the Alma and Belbek, despite two literature mentions without supporting records.

The conservation picture is equally complex. Ford and Freyhof assume A. mentoides is extinct in the Salhir, and Dyldin and colleagues note probable extinction in several Crimean rivers, including the Salhir and Chornaya, where the fish was once abundant enough to be sold regularly at the Simferopol market. Yet Boltachev and colleagues and Karpova reported high abundance of native shemaya in the Biyuk-Karasu, a former Salhir tributary now separated from the mainstream by irrigation transformations of the lower reaches. Karpova’s extensive surveys found the invasive common bleak, Alburnus alburnus, replacing the shemaya in the Salhir mainstream, while native shemaya persist in the southwestern Alma and Belbek and in the northeastern Biyuk-Karasu. If two distinct taxa occur in Crimea, A. mentoides should today be expected only in the Biyuk-Karasu.

For a species hovering between extinction and rediscovery, the return of its type specimens is more than a bibliographic footnote. A properly fixed lectotype from the Salhir watershed allows researchers to distinguish the Salhir shemaya from any southwestern Crimean relatives, a prerequisite for revising the entire Black Sea Alburnus species complex, whose phylogenetic relationships remain poorly understood. It also clarifies the status of Alburnus tauricus, another Kessler species believed to be a hybrid of the chub and a shemaya; if a hybrid, it should involve A. mentoides rather than the Caspian A. chalcoides, which is confined to the Caspian Sea watershed and does not occur on Crimea. From a lost name on a dusty label to a precisely measured specimen under X-ray in Vienna, the Crimean shemaya now has a stable taxonomic foundation, and with it, a better chance of being understood, and perhaps protected, before its remaining populations vanish.

Subject of Research: Rediscovery of lost type specimens and lectotype designation of the endangered Crimean shemaya fish Alburnus mentoides

Article Title: Rediscovery of lost syntypes of the Crimean shemaya Alburnus mentoides Kessler, 1859 ( Teleostei , Leuciscidae ) and designation of a lectotype

Article References: Ahnelt, H., Engelberger, S., & Bogutskaya, N. (2025). Rediscovery of lost syntypes of the Crimean shemaya Alburnus mentoides Kessler, 1859 (Teleostei, Leuciscidae) and designation of a lectotype. Annals of the Natural History Museum Vienna, 126, 27-40. https://doi.org/10.3897/anhmw.170125

Image Credits: AI Generated

DOI: 10.3897/anhmw.170125

Keywords: Alburnus mentoides, Crimean shemaya, lectotype, syntypes, taxonomy, cyprinidae, Black Sea, Crimea, museum collections, endangered species, Karl Kessler, Natural History Museum Vienna