Review of Oweniidae Rioja, 1917 (Annelida, Palaeoannelida) from Malaysia, with a description of two new species and a key to South China Sea species Author Ibrahim, Nur Fazne Institute of Oceanography and Environment (INOS), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu (Malaysia) Author Villalobos-Guerrero, Tulio F. Departamento Ecología Marina, Centro de Investigación Científica y de Educación Superior de Ensenada, 22860, Ensenada, Baja California (Mexico) Author Idris, Izwandy South China Sea Repository and Reference Centre (RRC), Institute of Oceanography and Environment, Universiti Malaysia Terengganu (INOS), 21030, Kuala Nerus, Terengganu (Malaysia) text Zoosystema 2024 2024-09-05 46 20 513 542 https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2024v46a20.pdf journal article 10.5252/zoosystema2024v46a20 1638-9387 ABFAAE4E-1226-48CA-8FC2-F0CCB1A89228 KEY TO THE GENERA AND SPECIES OF OWENIIDAE RIOJA , 1917 FROM THE SOUTH CHINA SEA (SCS) 1. Head with a crown of tentacles................................................................... Owenia Delle Chiaje, 1844 ....... 3 — Head without of a crown of tentacles .......................................................................................................... 2 2. Truncated head; groove present between first and second segments; mouth with mid-ventral slit forming large lateral lips ........................................................................................... Galathowenia Kirkegaard, 1959 ..... 5 — Rounded head; groove absent between first and second segments; button-hole-shaped mouth with low lips around .................................................................................................... Myriochele Malmgren, 1867 ...... 6 3. Tentacular crown with four pairs of long dichotomies and multi-branched tentacles; crown three-quarters as long, or as long as uniramous segment ........................................................................................................ 4 — Tentacular crown with three pairs of short dichotomies and poorly-branched tentacles; crown half as long as uniramous segment ........................................................................................................ O. unipinnata n. sp. 4. Cephalic region with prominent membranous collar; pygidium with 10 or more lobes surrounding anus; no lateroventral eyespots .......................................................................................... O. collaris ( Hartman, 1955 ) — Cephalic region with barely conspicuous collar; pygidium with two lobes; presence of lateroventral eyespots ... ................................................................................................................... O. fusiformis ( Delle Chiaje, 1844 ) 5. No lateroventral eyespots; pygidium with eight or more finger-like lobes surrounding anus; dwelling in deep waters ........................................................................................................ G. lobopygidiata ( Uschakov, 1950 ) — Presence of lateroventral eyespots; pygidium with only two blunt lobes; dwelling in shallow water ................. ............................................................................................................................................. G. minuta n. sp. 6. Tubes with accumulations of sponge spicules, foraminiferans or shell fragments exclusively; long size ( 15-20 mm , 25 segments); calibrated and aligned spicules, dwelling in deep water ..................... M. minor Caullery, 1944 — Tubes with accumulations of sand grains exclusively; short size ( 3-4 mm , 16 segments); dwelling in estuarine waters ...................................................................................................................... M. picta Southern, 1921