Hyporhamphus collettei, a new species of inshore halfbeak (Hemiramphidae) endemic to Bermuda, with comments on the biogeography of the Hyporhamphus unifasciatus species group

Abstract

A new species of halfbeak, Hyporhamphus collettei is described from Bermuda. Previously it was considered conspecific with the western Atlantic H. unifasciatus (Ranzani, 1842). When compared to H. unifasciatus, H. collettei is a more slender species and has lower meristic counts. Meristics were significantly different for dorsal-fin rays (usually 14–15), pectoral-fin rays (usually 10), and total second-arch gill rakers (usually 21–23). A number of morphometric ratios aided in distinguishing this species from its closest geographic neighbors, H. meeki from the east coast of the United States and H. unifasciatus from the Caribbean, and Central and South American coasts. When preorbital length to orbital diameter is compared, it is usually less than 0.70 in H. collettei and greater than 0.70 in H. meeki. Ratio of body depths at pectoral- and pelvic-fin origins to standard length usually less than 0.12 in H. collettei, and greater than 0.12 in H. unifasciatus. Sequence data for 800 bp of mtDNA Cyt b gene clearly separate the Bermudan species from other species of Hyporhamphus by a minimum genetic distance of 0.034.