Key to species of Arabella recorded from the Australian coast*: 1 Ventralmost chaeta in median and posterior chaetigers tapering abruptly to guards (Fig. 3 L). Subgenus Cenothrix ......... 2 – Ventralmost chaeta in median and posterior chaetigers tapering gradually to guards (Fig. 2 E). Subgenus Arabella ......... 3 2. (1) Chaetae robust in median and posterior chaetigers (Fig. 4 J–K, 6B). MxI robust or gracile distally falcate MxV with two teeth (Fig. 4 H)............................................................................ A. (C.) robusta n. sp. – Chaetae not robust in median and posterior chaetigers (Fig. 3 I, J). MxI and MxII polymorphic. MxI robust dentate or gracile distally falcate (Fig. 4B, C). MxV single tooth................................... A. (C.) mutans (Chamberlin, 1919) 3. (1) MxI gracile, basally dentate and distally falcate on both sides, right bifid (Fig. 1 J, L). MxII long on both sides (Fig. 1 I, K). Conspicuous ventral pads surrounding nephridiopores (Fig. 1 N)................................ A. (A.) pulvinata n. sp. – Left MxI robust, MxII short. Right MI gracile, MxII long...................................................... 4 4. (3) Posterior post-chaetal lobe longer than chaetae..................................... A. (A.) longipedata Monro, 1931 – Posterior post-chaetal lobe shorter than chaetae........................................................................... A. (A.) iricolor (Montagu, 1804) - probably, a complex of species, as it is currently recognized (Colbath 1989b).

Published as part of Zanol, Joana & Ruta, Christine, 2015, New and previously known species of Oenonidae (Polychaeta: Annelida) from Lizard Island, Great Barrier Reef, Australia, pp. 745-772 in Zootaxa 4019 (1) on pages 769-770, DOI: 10.11646/zootaxa.4019.1.26, http://zenodo.org/record/235654