The aim of this thesis was to review the current state of knowledge, occurrence and distribution of two polydorid (Polychaeta: Spionidae) genera, Polydora and Dipolydora, in estuaries of subtropical eastern Australia. The existing taxonomy of the polydorid group is confused and descriptions include many relative terms. A numerical taxonomy approach using Primer 6 was taken to identify species groups and characters. A standardized set of multivariate morphological characters was developed and resemblance analysis functions used to create species cluster groups. SIMPER (similarity percentages) analysis on the same dataset was used to identify the diagnostic characters for each of these species cluster groups and to identify new characters which could be useful in species diagnosis, particularly for frequently occurring incomplete specimens.Prior to this study 3 Polydora species and 4 Dipolydora species were recorded from subtropical eastern Australia. The present study found 12 Polydora species and 10 Dipolydora species from estuaries and bays of subtropical eastern Australia.Two Polydora species are new (Polydora sp. P1 and Polydora cf. woodwicki) and 7 are potentially new species (P. cf. latispinosa; P. cf. websteri; P. sp. P2S; P. sp. P3S; P. sp. P4S; P. sp. P5S and P. sp. P6S) having been described from single specimens. Polydora cornuta Bosc, 1902 is recorded from New South Wales for the first time. Polydora cf. calcarea is reported from mudblisters in oysters. The Australian form of Polydora hoplura Claparède, 1870 and P. haswelli Blake and Kudenov, 1978 are described more fully than in existing literature.Three Dipolydora species are new (Dipolydora sp. D1; D. cf. flava and D. sp. D2) and 4 from single specimens are potentially new (D. cf. aciculata/ cf. giardi; D. sp. D3S; D. sp. D4S and D. sp. D5S). Dipolydora tentaculata (Blake and Kudenov, 1978) and Australian forms of Dipolydora flava (Claparède, 1870) and Dipolydora socialis (Schmarda, 1861) are described more fully than in existing literature.Prior to this study one Dipolydora and no Polydora were recorded from the Tweed- Moreton bioregion. This study reports 6 species of Dipolydora and 5 species of Polydora from this bioregion.Dipolydora penicillata (Hutchings and Rainer, 1979) and Carazziella victoriensis Blake and Kudenov, 1978 are recommended for synonymy.It is recommended that Polydora ciliata (Johnston, 1838) be reinstated and Dipolydora ciliata (Johnson, 1838) removed from the Australian polychaete checklist following identification of an error in description translation.Important gaps in collections were identified for polydorids associated with oysters from estuaries over the whole subtropical region; and for polydorids from the Tweed-Moreton IMCRA bioregion.

The aim of this thesis was to review the current state of knowledge, occurrence and distribution of two polydorid (Polychaeta: Spionidae) genera, Polydora and Dipolydora, in estuaries of subtropical eastern Australia. The existing taxonomy of the polydorid group is confused and descriptions include many relative terms. A numerical taxonomy approach using Primer 6 was taken to identify species groups and characters. A standardized set of multivariate morphological characters was developed and resemblance analysis functions used to create species cluster groups. SIMPER (similarity percentages) analysis on the same dataset was used to identify the diagnostic characters for each of these species cluster groups and to identify new characters which could be useful in species diagnosis, particularly for frequently occurring incomplete specimens.Prior to this study 3 Polydora species and 4 Dipolydora species were recorded from subtropical eastern Australia. The present study found 12 Polydora species and 10 Dipolydora species from estuaries and bays of subtropical eastern Australia.Two Polydora species are new (Polydora sp. P1 and Polydora cf. woodwicki) and 7 are potentially new species (P. cf. latispinosa; P. cf. websteri; P. sp. P2S; P. sp. P3S; P. sp. P4S; P. sp. P5S and P. sp. P6S) having been described from single specimens. Polydora cornuta Bosc, 1902 is recorded from New South Wales for the first time. Polydora cf. calcarea is reported from mudblisters in oysters. The Australian form of Polydora hoplura Claparède, 1870 and P. haswelli Blake and Kudenov, 1978 are described more fully than in existing literature.Three Dipolydora species are new (Dipolydora sp. D1; D. cf. flava and D. sp. D2) and 4 from single specimens are potentially new (D. cf. aciculata/ cf. giardi; D. sp. D3S; D. sp. D4S and D. sp. D5S). Dipolydora tentaculata (Blake and Kudenov, 1978) and Australian forms of Dipolydora flava (Claparède, 1870) and Dipolydora socialis (Schmarda, 1861) are described more fully than in existing literature.Prior to this study one Dipolydora and no Polydora were recorded from the Tweed- Moreton bioregion. This study reports 6 species of Dipolydora and 5 species of Polydora from this bioregion.Dipolydora penicillata (Hutchings and Rainer, 1979) and Carazziella victoriensis Blake and Kudenov, 1978 are recommended for synonymy.It is recommended that Polydora ciliata (Johnston, 1838) be reinstated and Dipolydora ciliata (Johnson, 1838) removed from the Australian polychaete checklist following identification of an error in description translation.Important gaps in collections were identified for polydorids associated with oysters from estuaries over the whole subtropical region; and for polydorids from the Tweed-Moreton IMCRA bioregion.