Syngnathidae, Bonaparte, 1831

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 693-694

Family Syngnathidae

Pipefishes

Syngnathidae is characterised by an elongate body covered by a series of bony rings, a small mouth at the extremity of a long and slender snout, and the absence of pelvics (and caudal, dorsal, and anal) fins in some species. The bestknown members of the family are probably the marine sea horses ( Hippocampus ). The family includes approximately 220 species, mostly found in tropical marine waters. Several species enter estuaries and coastal lagoons, while others are strictly freshwater inhabitants. The trunk rings begin with the ring bearing the pectoral base and end with the ring bearing the anus (which usually bears the anal fin). The predorsal rings end with the ring bearing the first dorsal ray. The caudal rings begin with the first ring situated posterior to the anus and end with the penultimate ring. The terminal ring bears the caudal fin.

Syngnathus nigrolineatus and S. caspius regularly enter freshwater habitats in West Asia. Three additional species have been recorded to enter brackish waters of estuaries and coastal lagoons and may find their way into freshwater. These

Syngnathus nigrolineatus ; lower Danube, Romania; ~ 120 mm SL.

species can be distinguished using the key below. The diversity of the genus Syngnathus in the Mediterranean basin is significantly underestimated. Molecular studies indicate that several species may be confused under S. abaster . A critical review is required to ascertain the diversity and distribution of Mediterranean pipefishes. It is proposed that S. abaster be restricted to the coastal habitats of Spain, France, Corsica, and Sardinia. The Italian coastal species is identified as S. agassiz , described from Trieste, the freshwater species in the Black Sea basin as S. nigrolineatus , and the Caspian species as S. caspius . The well-defined molecular group found in Tunisia could be identified as S. algeriensis or S. flavescens in the future. From these, only S. algeriensis , S. caspius , and S. nigrolineatus regularly occur in freshwaters, while other species are restricted to marine or estuarine habitats. Syngnathus agassiz is expected to be found along the coast of the Eastern Mediterranean, but more research is needed to understand its distribution. The morphological characteristics that distinguish these different pipefishes have yet to be studied; thus, a definitive diagnosis cannot be provided. Further reading. Dawson 1985; Kuiter 1998; Wilson et al. 2010; Sanna et al. 2013 (molecular diversity).

Key to species of Syngnathidae in fresh and brackish waters in West Asia 1a - Caudal, pectoral and anal absent. ……………… Nerophis ophidion 1b - Caudal, pectoral and anal present. ………………2 2a - Anterior trunk rings not fused ventrally; snout compressed, anterior part deeper than head; up to 350 mm SL. ……………… Syngnathus typhle 2b - Anterior trunk rings ventrally fused; snout cylindrical. ………………3 3a - An elongated bump on top of head behind eye. ……………… Syngnathus acus 3b - No elongated bump on top of head behind eye, dorsal profile of head almost linear. ……………… Syngnathus caspius / S. nigrolineatus

Open Access. © 2025 JÖrg Freyhof, Baran Yoğurtçuoğlu, Arash Jouladeh-Roudbar and Cüneyt Kaya, published by De Gruyter. the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

https://doi.org/10.1515/9783111677811-036

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694 Family Syngnathidae

Syngnathus caspius ; Gorgan Bay, Iran; male with egg pouch under tail, 110 mm SL. © R. Patimar.