Four new species of Marphysa (Annelida, Eunicida, Eunicidae) from the east coast of Peninsular Malaysia.

Four new species of Marphysa are described from Terengganu state on the east coast of Peninsular Malaysia, using morphological and molecular (cytochrome oxidase subunit I (COI) gene) data. These species belong to different groups of Marphysa: Marphysakertehensis sp. nov. belongs to Group A (Mossambica), Marphysamerchangensis sp. nov. and Marphysasetiuense sp. nov. belong to Group B (Sanguinea) and Marphysaibaiensis sp. nov. belongs to Group E (Gravelyi). Marphysakertehensis sp. nov. is characterised by having only limbate chaetae, absence of subacicular hooks, three types of pectinate chaetae including wide, thick isodont with short and slender inner teeth, and pectinate branchiae with up to nine branchial filaments. Marphysamerchangensis sp. nov. is characterised by the presence of eyes, unidentate subacicular hooks, four types of pectinate chaetae including wide, thick anodont pectinate chaetae with five long and thick inner teeth, and pectinate branchiae with up to six branchial filaments. Marphysasetiuense sp. nov. has mostly unidentate subacicular hooks (bidentate on several posterior chaetigers), four types of pectinate chaetae including wide, thick anodont pectinate chaetae with seven thick and long inner teeth, and pectinate branchiae with up to five branchial filaments. Marphysaibaiensis sp. nov. has bidentate subacicular hooks throughout, five types of pectinate chaetae, including a heterodont with 12 short and slender inner teeth, and pectinate branchiae with up to eight branchial filaments. The designation of these new species based on morphology is fully supported by molecular data. Habitat descriptions of each species are also included.

Two new species of Marphysa (Annelida, Eunicidae) from southern Australia.

Two new species of Marphysa Quatrefages, 1866 are described from the southeast coast of Australia. With the presence of only compound spinigers and the branchiae present over many chaetigers, Marphysa baudini n. sp. belongs to the Sanguinea-group. This species has ventral cirri with an inflated base and digitiform tip and thick and wide anodont pectinate chaetae, with 3-5 internal long and thick teeth. With the presence of only compound falcigers, Marphysa davidattenboroughi n. sp., belongs to the "Aenea-group". This species is characterised by the presence of a bilobed prostomium, a single pair of pygidial cirri and by the presence of thick, and wide anodont pectinate chaetae with 4-6 long internal and thick teeth.