Tiburonia granrojo n. sp., a mesopelagic scyphomedusa from the Pacific Ocean representing the type of a new subfamily (class Scyphozoa: order Semaeostomeae: family Ulmaridae: subfamily Tiburoniinae subfam. nov.)

Submersible observations off Japan, Hawaii, and California, USA, at depths of 645–1497 m, have revealed a previously undescribed species of large semaeostome scyphomedusa. These observations were made from 1993 to 2002. The medusa, Tiburonia granrojo n. sp. is sufficiently different from other species in the family Ulmariidae to justify the creation of a new subfamily (Tiburoniinae). This subfamily and species are distinct in overall bell morphology and color, lacking any marginal tentacles, and having four to seven short, thick oral arms that extend beyond the bell margin. The entire medusa, including the mesoglea, is a deep red. A new key to the subfamilies of the Ulmaridae and large subunit rRNA sequence information for T. granrojo are provided. That new species of this size and mass are still being discovered in the deep waters of the world suggests that deep-water species remain undescribed.Additional information is available at http://www.mbari.org/midwater