A global revision of the Seahorses Hippocampus Rafinesque 1810 (Actinopterygii: Syngnathiformes): Taxonomy and biogeography with recommendations for further research

Abstract

Nomenclatural clarity is vital for the collection, dissemination, and retrieval of natural history information, which itself is necessary for effective conservation and management of species. Seahorses (genus Hippocampus) are small marine fishes that in many cases are heavily exploited and suffering severe population declines worldwide, leading to conservation concern and action. Here we provide a brief history of seahorse taxonomy, and attempt to clarify seahorse nomenclature by reducing redundancy and exposing areas of disagreement in need of further study. We provide an annotated list of the 41 species we currently recognize as valid, and describe their geographical distributions to offer a solid foundation for future research and conservation efforts. We base our conclusions on available morphological, genetic and distributional data, re-examination of the relevant literature, previous examination of almost all original type specimens, familiarity with many thousands of other live and dead specimens, and photographs of seahorses. This work should lead to greater taxonomic clarity by highlighting known research gaps and by ensuring that each species designation is justified by robust and defensible taxonomic protocols. Such clarity should facilitate greater efficacy in management and conservation.

DNA barcoding reflects the diversity and variety of brooding traits of fish species in the family Syngnathidae along China’s coast

“…Seamoths may be the primitive sister group of the seahorses, pipefish and seadragons (Pietsch, 1978). About 41valid seahorse species and over 400 pipefish species have been described along the majority inhabiting shallow seabed of the Indo-central western Pacific Oceans (below latitude 26 • N) (Dawson, 1985;Koldewey and Martin-Smith, 2010;Lourie et al, 2016). Seahorses sold as traditional Chinese medicine, ornaments and aquaria presentation have shown increasing value in recent years (Koldewey and MartinSmith, 2010;Lin et al, 2008).…”

Hippocampus japapigu, a new species of pygmy seahorse from Japan, with a redescription of H. pontohi (Teleostei, Syngnathidae)

“…The family occurs worldwide in shallow temperate to tropical waters in a range of habitats, including seagrass beds, estuaries, coral and rocky reefs, and mangroves (Foster and Vincent 2004; Kuiter 2009; Froese and Pauly 2018). Pygmy seahorses of the genus Hippocampus Rafinesque, 1810 are diminutive in size (13.6–26 mm SL), live in close association with octocorals, colonial hydrozoans, bryozoans, seagrass and algae, and are morphologically distinct from the more numerous and larger species (24–350mm SL) of seahorses in possessing a single rather than paired gill openings and trunk brooding of their young (Whitley 1970; Kuiter 2003; Lourie and Randall 2003; Lourie and Kuiter 2008; Gomon and Kuiter 2009; Lourie et al 2016). …”

“…Six pygmy seahorse species are currently recognized and documented throughout the central Indo-Pacific, ranging from the Coral Triangle, West Pacific, Australia, to central Japan: H.bargibanti , H.denise Lourie & Randall, 2003, H.colemani Kuiter, 2003, H.pontohi Lourie & Kuiter, 2008, H.satomiae Gomon & Kuiter, 2009, and H.waleananus Gomon & Kuiter, 2009 (Whitley 1970; Kuiter 2003; Lourie and Randall 2003; Senou et al 2006, 2007, 2008; Baine and Harasti 2007; Lourie and Kuiter 2008; Motomura et al 2010; Allen and Erdmann 2012; Smith et al 2012). Lourie et al’s (2016) revision of the genus Hippocampus informally placed H.waleananus in synonymy with H.satomiae . However, we recognize the current taxonomic status of H.waleananus as valid based on differences in diagnostic morphological characters, including tail ring counts, coronet profile, and body ornamentation (Tables 1, 3), and host association and diurnal versus nocturnal behavior.…”

“…However, we recognize the current taxonomic status of H.waleananus as valid based on differences in diagnostic morphological characters, including tail ring counts, coronet profile, and body ornamentation (Tables 1, 3), and host association and diurnal versus nocturnal behavior. Another described pygmy species, Hippocampussevernsi (Lourie & Kuiter, 2008), was distinguished from H.pontohi primarily by features of coloration in life, however the invalidity of this species was subsequently recognised as coloration is not a reliable morphological diagnostic character in seahorses (Lourie et al 2004, 2008, 2016). Here, as part of this study, we formally synonymize H.severnsi under H.pontohi based on mitochondrial COI genetic data.…”

Caracterización de las poblaciones de caballitos de mar en diferentes zonas de la costa norte de las regiones occidental y central de Cuba

“…De las 41 especies de caballitos de mar reconocidas como válidas por Lourie et al (2016), en Cuba solo se han encontrado dos especies: Hippocampus erectus (Perry, 1810) e Hippocampus reidi (Ginsburg, 1933), las cuales desde el año 2011 están incluidas en el Apéndice II de la Resolución No. 160/2011 sobre Regulaciones para el control y la protección de especies de especial significación para la diversidad biológica en Cuba (Gaceta Oficial de la República de Cuba, 2011).…”