R Moura

Environmental Processes, Biodiversity and Changes in Admiralty Bay, King George Island, Antarctica

The isolation of Antarctica from South America during the Oligocene (~35 mya) formed the Southern Ocean, generated the northward flow of the Atlantic Antarctic Bottom Water, and numerous unique geological and oceanic processes (e.g. an active spreading centre in the Bransfield Strait, ridge trench collision, gas hydrates on modern sediments, and complex circulation) along the northern end of the Antarctic Peninsula in particular (Barker and Burrell 1982; Pearse et al. 2001; Barker and Thomas 2004; Thomson 2004; Turner et al. 2009).

Anthropogenic impacts on sub-Antarctic and Antarctic islands and the adjacent marine environments

The impacts of human activities are more apparent at present in the sub-Antarctic than in the Antarctic. The sub-Antarctic islands, despite their physical isolation in the Southern Ocean, are generally more accessible, have less challenging climates, and a longer history of human presence than the more southern latitudes of the Peninsula and continent.

Macrostructure and evolution of the digestive system in Echinoida (Echinodermata)

The structure of the digestive system in Echinoida has long been puzzling since comparative studies have suggested that a derived structure, the siphon, has apparently evolved twice independently. New observations on the digestive system in five species of Cidaroida, four species of the Diadematoida and three species of Echinothurioida are presented. The results show that the four diadematoid species have a siphon and the three species of Echinothurioida have a siphonal groove, contrary to previous assertions. These observations make the macrostructure of the echinoid digestive system fully consistent with more recent phylogenetic hypotheses based on molecular and general morphological data, and support the idea that a siphon has evolved only once, in the stem lineage of the Acroechinoidea.

Rediscovery of the poorly known sea urchin Centrostephanus longispinus rubicingulus (H.L. Clark, 1921) (Echinodermata, Echinoidea, Diadematidae) on the continental shelf of Brazil, with notes on its morphology and synonymy

ABSTRACT The sea urchin Centrostephanus longispinus rubicingulus was rediscovered on the continental shelf of Brazil. The subspecies was merely recorded in 1955, when Bernasconi described Centrostephanus besnardi (a synonym of C. longispinus rubicingulus), on the basis of two specimens collected at Trindade Island (State of Espírito Santo). This is the first record of this subspecies for northeastern Brazil (State of Rio Grande do Norte). A description is provided, along with comments on morphology and synonymy, illustrations of diagnostic characters and, for the first time, SEM figures of the pedicellariae of C. longispinus rubicingulus. An extended list of synonyms for the genus and species is included. This record raises the number of echinoids known from Northeastern Brazil to 32 species.