Family Kophobelemnidae Gray, 1860 Diagnosis (from Williams 1990): Bilateral, club-like colonies. With autozooids arranged in longitudinal rows along the rachis. Big autozooids without calyces. Siphonozooids with calyces, located at the base of the autozooids. Sclerites present in all tissues (peduncle, rachis and polyps), with different morphology (three-flanged, tuberculatespindles, plate-like, ovals or rod-like). Included genera: Kophobelemnon Asbjørnsen, 1856; Sclerobelemnon Kölliker, 1872; Malacobelemnon Tixier-Durivault, 1965. Type genus: Kophobelemnon. Distribution: Cosmopolitan. From intertidal waters to about 5000 m depth (Williams 2011). Kophobelemnon Asbjørnsen, 1856 Type species: Pennatula stellifera Müller, 1776. Valid species: Kophobelemnon stelliferum (Müller, 1776); Kophobelemnon affine Studer, 1894; Kophobelemnon heterospinosum Kükenthal, 1910; Kophobelemnon pauciflorum Hickson, 1916; Kophobelemnon macrospinosum Thomson & Renet, 1927; Kophobelemnon biflorum Pasternak, 1960; Kophobelemnon irregulatus Keller, Pasternak & Naumov, 1975; Kophobelemnon molanderi Pasternak, 1975. Diagnosis (from Williams 1990): Colonies rigid, club-like, distal region expanded where inserts free, big autozooids. In some cases, autozooids retractile, in longitudinal, alternate rows. Rachis could be rounded in its terminal region. Internal axis through the entire colony, rounded or slightly quadrangular in cross section. Conspicuous, three-flanged sclerites, could have protuberances. Distribution: Cosmopolitan, from intertidal to about 5000 m depth (Williams 2011). New record of the genus in the Southwestern Atlantic Ocean off Argentina, its bathymetric range in the studied area goes from 2900 m to about 3300 m depth.

Published as part of Risaro, Jessica & Abstract, Daniel Lauretta, 2023, Sea Pens (Cnidaria: Octocorallia: Pennatuloidea) From The Mar Del Plata Submarine Canyon And Outskirts, pp. 401-433 in Zootaxa 5389 (4) on pages 415-416, DOI: 10.11646/zootaxa.5389.4.1, http://zenodo.org/record/10417392