Umbellula pomona sp. nov., a new sea pen from Mar del Plata Submarine Canyon (Cnidaria: Octocorallia: Pennatulacea)

JESSICA RISARO; DANIEL LAURETTA; GARY C. WILLIAMS; DANIELA PEREYRA

European Journal of Taxonomy

Museum National d´Histoire

Año: 2020 p. 121 - 143

Abstract. Sea pens (Cnidaria: Anthozoa: Pennatulacea) constitute a distinctive group of colonial marineinvertebrates. They inhabit the world`s oceans, from shallow to deep waters. Studies about this groupin Argentina are scarce, and no species have been described in the area in over a decade. Based onsamples collected in Mar del Plata Submarine Canyon at about 3000 m deep we describe a new speciesof sea pen, Umbellula pomona Risaro, Williams & Lauretta sp. nov. This is a spiculate Umbellula thatdiffers from other species of Umbellula with sclerites, by the number, development and distribution ofthe autozooids in its terminal cluster, as well as the shape of its axis. Molecular data also distinguishes itfrom other known species. Of the forty-three described species approximately ten are considered validfor the genus Umbellula, four of them are registered for the South Atlantic Ocean and only three aredescribed for the Antarctic region. Since sampling efforts in this area have been scarce, the number ofspecies of sea pens from the region is likely to increase substantially in the coming years.