Multiple branching and attachment structures in cloudinomorphs, Nama Group, Namibia

The Ediacaran-Cambrian cloudinomorphs, which include Cloudina, are the first putative skeletal metazoans. They have a benthic ecology and tubular, organic, or biomineralized stacked funnel morphologies but an unresolved phylogenetic affinity. Rare dichotomous branching has been described in Cloudina, but here we demonstrate the presence of multiple (polytomous), dichotomous branching in cloudinomorphs from a microbial mat community from the Nama Group, Namibia, as revealed by three-dimensional models created from serial sections. Branches share an open, central cavity, and branching is achieved via external budding. These cloudinomorphs show attachment and mutual cementation to each other, and also to Namacalathus, via extratubular skeletal structures to potentially form a horizontal framework. Polytomous branching excludes a bilaterian affinity as proposed for other cloudinomorphs. This raises the possibility that the Ediacaran tubular, funnel morphology is convergent, and that cloudinomorphs may, in fact, represent taxa of diverse affinity.

Taxonomy and distribution of Terebellides (Polychaeta: Trichobranchidae) in the northern South China Sea, with description of three new species

Benthic ecology monitoring in the northern South China Sea revealed many individuals of the polychaete genus Terebellides (Annelida), which are common in soft sediments in shallow waters (4.5–41.0 m). Three new species of Terebellides are described, including T. guangdongensis n. sp., T. yangi n. sp. and T. ectopium n. sp. Terebellides guangdongensis n. sp. is mainly found in Guangdong waters. Terebellides yangi n. sp. and T. ectopium n. sp. are mainly found in Beibu Gulf. A key to all described species of Terebellides from the Northwestern Pacific is given.

Insights into the Great Australian Bight gained through marine geology and benthic ecology studies

While the Great Australian Bight (GAB) represents one of the most prospective deep water basins in Australia, its vast geographic extent and deep sedimentary sequences remain poorly characterised. Recently, multidisciplinary research has been conducted to better characterise the continental and abyssal slope of the Ceduna Sub-basin. The Great Australian Bight Deepwater Marine Program (GABDMP) aimed to build a regional understanding of the deep water GAB marine geology and benthic ecology. This three-year research program encompassed four research voyages that aimed to sample and characterise deep water outcropping facies, volcanic seamounts, potential seeps and their associated biological communities. These voyages used a variety of equipment to achieve the research goals and included the deployment of autonomous underwater and remotely operated vehicles and a seafloor coring system. Numerous sites across the Ceduna Sub-basin from 700 to 5501 m water depth were studied. Sampling operations collected over 2.8 tons of rocks, 148 m of core, 55 698 biological specimens and 48 097 km2 of mapping data. Nearly 4000 geological samples have been analysed to date. This paper will summarise the key findings from the GABDMP and the geological and biological insights that have been revealed through this multidisciplinary research program.