Here we report on the first finding of Nanozoanthidae (Anthozoa: Hexacorallia: Zoantharia) in the Red Sea and the first record west of Western Australia. A single specimen of Nanozoanthus sp. was found at a depth of 13 m off Dumsuq Island, the Farasan Islands, Saudi Arabia (16°33.846′N 42°03.510′E) during SCUBA surveys. Previous research had hypothesized that the genus could potentially be widespread in the Indo-Pacific and was simply undetected due to its small and cryptic nature, and the current specimen provides support for this idea. Such findings demonstrate the importance of biodiversity surveys by taxonomic specialists in understudied marine regions.

This study examined the trophic ecology of the zoanthid Palythoa caribaeorum in tropical reefs and evaluated its role in the energy flow in that ecosystem. Colonies of this species were sampled in the infralittoral zone of reefs in north-eastern Brazil in 2008. We calculated the richness, total abundance, relative abundance and frequency of occurrence of prey items. The biovolumes and weighted biovolumes of prey were calculated to characterize the most important food items in terms of their biomasses. To evaluate the selectivity, zoanthid and plankton samples were collected in 2010. Pennate diatoms were the most abundant and most frequent prey and, together with invertebrate eggs, constituted the most important food items in terms of their biomasses. There were no significant differences in abundance or richness among the different beaches studied, nor between the different seasons. The mean size of prey items within the polyps was significantly smaller than of the general plankton, indicating that P. caribaeorum selected for (or limited) certain prey sizes. This species predominantly fed on diatoms, and did not take advantage of many other prey items abundant in the plankton. Our results indicate that P. caribaeorum is suspensivorous and feeds principally on small phytoplankton. As this species is prey for benthic organisms such as polychaetes and nektonic organisms, our results indicate the importance of this zoanthid in tropical reef ecosystems as a primary consumer that serves as an energy transfer link between the planktonic environment and the nektonic and benthic spheres.

This is the first report on the Zoantharia fauna (Cnidaria: Hexacorallia) of the isolated oceanic island of Ascension, southern Atlantic, where zoantharians are a dominant component of the shallow-water benthos. Specimens from two expeditions (1983, 2012) were examined regarding external morphology and molecular phylogeny using three DNA markers, which confirmed the presence of four zoantharian species: Palythoa caribaeorum; Palythoa aff. clavata; Parazoanthus swiftii; and Zoanthus sp. Two of these, Palythoa aff. clavata and Parazoanthus swiftii, were previously only known from the western Atlantic and Caribbean. Molecular examination of the zooxanthellae (=Symbiodinium spp.) of Palythoa specimens showed that they were in association with only one type, subclade C1.

Savalia savaglia (Anthozoa: Zoantharia) is an uncommon, large, arborescent, modular species best known from the western basin of the Mediterranean Sea, and recorded recently from the Canary Islands. During dives in the Ría de Arousa (Galicia, north-western Spain, north-eastern Atlantic), four colonies were seen at a depth of 26–29 m, and identified by morphological study, including the cnidome, and DNA sequencing. These new records extend considerably the distribution of the species. Given that S. savaglia lives in the north-west of the Iberian Peninsula, overlooked old records from the literature further north from the Bay of Biscay may be reliable.