Schizocypris, Schizopygopsis & Schizothorax Snow barbel or snow trouts are common names for two large, monophyletic radiations of Asian high-altitude cyprinids. All but one genus this book covers belong to Schizothoracinae, which includes four genera. Only Schizopygopsis is placed in the subfamily Schizopygopsinae, consisting of nine snow barbels genera. Phylogenetic hypotheses derived from several studies suggest that these groups may have originated repeatedly and ambiguously through hybridisation and polyploidisation within the Cyprinidae family. This may be responsible for the controversial classification among subfamilies. The history of polyploidisation in Cyprinidae remains uncertain, presenting significant challenges for phylogenetic systematics. Preliminary results indicate that Schizothoracinae and Schizopygopsinae are the maternal siblings of Cyprininae and paternal siblings of Torinae. This hypothesis suggests that hybridisation between early carps and yellowfish may have played a pivotal role in the evolution of snow barbels. Snow barbels are speciose and abundant in the mountains east of the Zagros and Elbrus. They are often the most common fish in these regions, dominating the fish communities by biomass. Snow barbels are highly specialised and represent the ecological pendants of barbels and scrapers. Several species show high individual variation in head and mouth shape and the development of lips. Snow barbels are a large group of fishes (more than 150 species) but only occur marginally in the area covered by this book. Their taxonomy and species diversity have never been comprehensively studied, and much remains to be done. Two species of Schizothorax and one species of Schizocypris occur in Eastern Iran. Schizopygopsis stoliczkai is occasionally reported from the fauna of Iran (Sistan basin), and Schizothorax intermedius is listed for the Hari. These records are based on misidentifications, and our area has no documented records of these species. Schizothorax intermedius is likely restricted to the upper Indus drainage, while S. stoliczkai is widely distributed in mountain areas of Afghanistan, Pakistan, India, and western China. As is the case with barbel eggs, the eggs of these fish are poisonous to humans. Deaths have been reported as a result of eating the eggs of Schizothorax. Severe cases present with muscular cramps, paralysis, convulsions, and coma. Victims typically recover within 3–5 days after stomach evacuation, although this may take longer. It is advisable to exercise caution when consuming fish during its breeding season, as it is important to ensure that all traces of the eggs are removed to avoid contamination of the flesh. It should be noted that cooking does not destroy the toxin. Further reading. Yang et al. 2015 (phylogeny of Cyprinidae); Tan & Armbruster 2018 (subfamilies in Cyprinidae). Key to species of snow barbels in Iran. 1a - Barbels absent. 2a - 9–18 gill rakers. …......... Schizocypris altidorsalis …......... Schizothorax pelzami 1b - Two pairs of barbels. 2b - 21–41 gill rakers. …......... 2 …......... Schizothorax zarudnyi

Published as part of Freyhof, Jörg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, GmbH, Berlin / Boston :De Gruyter on pages 241-243, DOI: 10.1515/9783111677811, http://zenodo.org/record/17881367