A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian mission HUD2010-029 and the British RRS Discovery Cruise DY081, on the Orphan Seamount near the Orphan Knoll, northwest Atlantic, between 2999.88 and 3450.4 m depth. Orphan Knoll is an isolated, drowned continental fragment 550 km northeast Newfoundland in the Labrador Sea. This region is biologically rich and complex and in 2007, the regional fisheries management organization operating in the area regulated that no vessel shall engage in bottom-contact fishing activities until reviewed in 2020 with a review slated at the end of this year. Members of the genus Tedania are uncommon in the temperate northern hemisphere with only six species known previously: Tedania (Tedania) anhelans; Tedania (Tedania) pilarriosae; Tedania (Tedania) suctoria; Tedania (Tedania) urgorrii; Tedania (Tedaniopsis) gurjanovae; and Tedania (Tedaniopsis) phacellina. The particular features of the new sponge we describe are the very peculiar external morphology which is tree-like with dichotomous branching—a morphology not previously described in this subgenus; and the combination of spicules found: long styles, the typical tornotes of the subgenus and two sizes of onychaetes. Additional information is provided on other species of Tedaniopsis described from the Atlantic Ocean. Based on the characteristics reported, we propose a new species, Tedania (Tedaniopsis) rappi sp. nov. in honor of Prof. Hans Tore Rapp (1972–2020), University of Bergen, Norway, a renowned sponge taxonomist and coordinator of the Horizon 2020 SponGES project. The holotype of T. (T.) phacellina Topsent, 1912 from the Azores, the only other northern Atlantic species in the subgenus Tedaniopsis, was reviewed for comparison.
Keywords: sponges, VMEs, taxonomy, new species, Tedania (Tedaniopsis) rappi
Phylum PORIFERA Grant, 1836
Class DEMOSPONGIAE Sollas, 1885
SubClass HETEROSCLEROMORPHA Cárdenaset al., 2012
Order POECILOSCLERIDA Topsent, 1928
Family TEDANIIDAE Ridley and Dendy, 1886
Genus Tedania Gray, 1867
Definition: Tedaniidae with differentiated ectosomal and choanosomal megascleres Van Soest (2002).
Subgenus Tedaniopsis Dendy, 1924
Diagnosis: Tedania with relatively long thick, smooth styles, occasionally modified to anisostrongyles or anisoxeas, as structural megascleres. Ectosomal megascleres are mucronate or tylostrongylote tornotes occasionally with one or more vestigial spines (Desqueyroux-Faúndez and Van Soest, 1996).
Tedania (Tedaniopsis) rappi Ríos, Cristobo and Kenchington sp. nov.
Type material: Holotype: TBD Orphan Seamount (NW Atlantic), 50.1119; −45.3199. Depth 2999.88 m, Coll. CCGS Hudson, 19.07.2010, 1 specimen. Rock substrate. In 70% Ethanol Canadian Museum of Nature number CMNI 2020-0004. Paratype: Atlantic Reference Centre (ARC) Museum (ARC 81604) Orphan Seamount (NW Atlantic), 50.0484; -45.3757, 3,450 m depth, Coll. RRS Discovery, 08.07.2017, 1 specimen. Rock substrate. In 100% Ethanol.
Holotype of Tedania (Tedaniopsis) phacellina Topsent, 1912, was revised. Museé Oceanographique Monaco; Collection of S.A.S. Le Prince de Monaco Station 2183, 28th August 1905, 1,998 m in depth. A small fragment (Schizotype) was analyzed by SEM.
Derivatio nominis: In honor of Prof. Hans Tore Rapp (1972–2020), University of Bergen, Norway, a renowned sponge taxonomist and dear colleague, who described 50 new species of sponges for science. Prof. Rapp was also coordinator and leader of the EU Horizon 2020 SponGES project which focused much needed attention on deep-sea sponges and their habitats.
Pilar Ríos, Javier Cristobo, Emily Baker, Lindsay Beazley, Timothy Culwick and Ellen Kenchington. 2021. Increasing Knowledge of Biodiversity on the Orphan Seamount: A New Species of Tedania (Tedaniopsis) Dendy, 1924. Front. Mar. Sci. 8:612857. DOI: 10.3389/fmars.2021.612857