Odd family reunion: DNA barcoding reveals unexpected relationship between three hydrozoan species.

Knowledge of life histories is crucial for understanding ecological and evolutionary processes, but for many hydrozoan species only incomplete life cycles have been described due to challenges in linking hydromedusae with their polyp stages. Using a combination of DNA barcoding, morphology, and ecological information, we describe for the first time the polyp stage of Agassiz, 1865 and re-describe that of (Romanes, 1876). Campanulinid hydroids referable to Sars, 1874 and collected in the same biogeographic region as the type locality of this species are shown to be the polyp stage of these two mitrocomid hydromedusae.

Hiding in plain sight- (Ctenophora) in Norwegian waters.

Cydippid ctenophores of genus have been rarely reported from the north-east Atlantic in the scientific literature. The conspicuous lack of previous records is likely attributable to methodological constraints detrimental to sampling ctenophores, including the use of plankton nets and preservation of samples as well as poor identification literature and a lack of taxonomic expertise on gelatinous zooplankton. Here, we have compiled published and novel records as well as documented diver observations, of spp.

Abundance, distribution and diversity of gelatinous predators along the northern Mid-Atlantic Ridge: A comparison of different sampling methodologies.

The diversity and distribution of gelatinous zooplankton were investigated along the northern Mid-Atlantic Ridge (MAR) from June to August 2004.Here, we present results from macrozooplankton trawl sampling, as well as comparisons made between five different methodologies that were employed during the MAR-ECO survey. In total, 16 species of hydromedusae, 31 species of siphonophores and four species of scyphozoans were identified to species level from macrozooplankton trawl samples.

Swimming and feeding in (Scyphozoa, Coronatae).

Some western Norwegian fjords host extraordinarily abundant and persistent populations of the mesopelagic, coronate scyphomedusa, . In these environments, from late autumn to spring, the medusae undertake regular diel vertical migrations into surface waters. From unique observations obtained with a remotely operated vehicle (ROV), including observations made without artificial light, we observed that 90% of the medusae swam with their tentacles in aboral position.