Annelids of the eastern Australian abyss collected by the 2017 RV 'Investigator' voyage.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world's ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Two new species of Sabellariidae (Annelida, Polychaeta) from the abyss of eastern Australia.

In May-June 2017 an expedition on board RV 'Investigator' sampled benthic communities along the lower slope and abyss of eastern Australia from off Tasmania to the Coral Sea. Over 200 sabellariid specimens of the genera Phalacrostemma and Gesaia were collected during the voyage and deposited in the Australian Museum. Here we describe two new species Gesaia csiro n. sp. (4414-4436 m) and Phalacrostemma timoharai n. sp. (1013-1093 m). We did not formally describe another species of Phalacrostemma due to poor condition of the single specimen. Gesaia csiro n. sp. is the first record of the genus from Australian waters (only a planktonic larva attributed to the genus has previously been recorded), and it can be distinguished from other congeners by the smooth surface of inner paleae, distal thecae of outer paleae with long, irregular and expanded distal fringe and circled distal margin. Phalacrostemma timoharai n. sp. differs from congeners by the following combination of characters: presence of the buccal flap, absence of tentacular filament, 18-22 pairs of outer paleae, two pairs of neuropodial cirri on first thoracic segment, and only one pair of lateral lobes on second thoracic segment. Morphological descriptions are accompanied by mitochondrial cytochrome c oxidase subunit 1 (COI) and ribosomal (16S, 18S and 28S) sequence data. A key to all Australian species of sabellariids is given.

A new species of the sanguinea-group Quatrefages, 1866 (Annelida: Eunicidae: Marphysa) from the Philippines.

A new species of the Marphysa sanguinea group, M. iloiloensis n. sp. (Annelida: Eunicida: Eunicidae), is described from the Marine Annelids Hatchery of the Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC- AQD), Iloilo Province, Philippines. It represents the first record of this group in the Philippines. The new species is most similar morphologically to M. hongkongensa Wang, Zhang Qiu, 2018, but can be distinguished from it by having fewer branchial filaments, a pair of faint eyes (absent in M. hongkongensa), and in slight differences in jaw morphology and chaetation. The embryos of the new species develop inside a jelly cocoon attached to the entrance of the adult burrow; this is the first time that egg-containing cocoons have been found in any species of the sanguinea-group. Phylogenetic analysis based on the mitochondrial gene cytochrome c oxidase subunit I (COI) revealed that Marphysa iloiloensis n. sp. is genetically distinct from all other analysed Marphysa species and forms a sister group to M. hongkongensa. A revised identification key to members of the sanguinea-group in Southeast Asia is provided.

Southern high latitude squat lobsters II: description of Uroptychus macquariae sp. nov. from Macquarie Ridge.

Squat lobsters have only recently been recorded from the Macquarie Ridge, which extends south between New Zealand and Antarctica. Among these, Uroptychus insignis (Henderson, 1885) was recorded for the first time outside the western Indian Ocean, exhibiting only subtle morphological differences. Reexamination of the Macquarie Ridge and Indian Ocean specimens attributed to U. insignis using morphological and molecular data revealed the Macquarie Ridge form to represent a separate species. Subtle but consistent morphological differences are evident and partial CO1 sequence data indicates that the specimens collected on Macquarie Ridge differ from those collected in the Indian Ocean by more than 7%. The Macquarie Ridge species is described herein as Uroptychus macquariae n.sp. Subtle morphological differences between the new species and U. insignis are discussed.