New caulerpenyne-derived metabolites of an Elysia sacoglossan from the South Indian coast.
Chemical analysis of the secondary metabolite pattern of the sacoglossan mollusc Elysia cf. expansa, collected along South Indian coasts, showed the presence of the typical Caulerpa-derived sesquiterpene caulerpenyne (1) and two new minor co- occurring metabolites, the compounds dihydrocaulerpenyne (4) and expansinol (5). The chemical characterization of these molecules, structurally related to 1, is reported.
Marine Opisthobranch Molluscs: Chemistry and Ecology in Sacoglossans and Dorids


Opisthobranchs are marine molluscs apparently unprotected by physical constraints of a shell which is either reduced or completely absent in the adults. Their survival is based on a series of defensive strategies, which involve cryptic behaviour and use of deterrents. During the last twenty years, many studies have been performed to characterize the chemicals isolable
from these animals. In this paper we summarize the studies covering two large groups of
opistobranch molluscs: sacoglossans and dorids. The main aim is to give to the readers a brief view of the compounds isolated from these molluscs, and, when it is possible, to suggest an ecological role for them. The Order Sacoglossa has been selected as it contains a wide range of morphological types from primitive species with a relatively strong external shell to shell-less types. The chemical studies of these molluscs have been reviewed with the aim of constructing a general scenario based on chemical evidence. Similar reasons prompted us to review the chemical data of the shell-less dorid nudibranchs belonging to the superfamilies Eudoridoidea and Bathydoridoidea. In this case, the review dates from the literature subsequent to Karuso's
1987 review "Chemical Ecology of Nudibranchs". The selection of the two groups, sacoglossans and dorids, is also due to their different, but exclusive feeding habits, green algae for sacoglossans and sponges for dorids. The critical analysis of all these studies illuminates the extraordinary capability of opisthobranch molluscs to create new chemistry through either bio­ accumulation of selected metabolites from their dietary sources, bio-transformation of dietary compounds, or de novo bio-synthesis of useful chemicals. However, it is difficult to determine the boundaries of these investigations. In fact, their ecological contributions are relevant and applications useful for man are foreseable.

Mesozoic rifting and basin inversion along the northern African Tethyan margin: an overview
Abstract The northern African Tethyan margin registered three major rifting episodes from the latest Palaeozoic-earliest Mesozoic to the earliest Cenozoic. Break-up of Gondwana was initiated in the late Carboniferous. Along the northern African-Arabian plate margin rifting propagated westward from the northeastern Arabian margin to Morocco during the Permian and Triassic, and was accompanied by Mid-Late Triassic-earliest Liassic extensive alkaline flow basalts. Rifting continued during the Liassic, e.g. in the Moghrebian Atlas troughs. A second stage of rifting occurred in the Late Jurassic and continued into, or was rejuvenated during, the Early Cretaceous. Along the east Mediterranean margin, some large E-W trending rifts formed, often with associated volcanism, e.g. southern Sirt and Abu Gharadig. Most researchers believe the oceanization of the eastern Mediterranean basin occurred at this time. Flexural subsidence affected the Moghrebian Atlas, including the Riffian-Tellian domain, where a thick flysch series was deposited. Two short-lived, but widespread and tectonically important, compressional or wrench-dominated events occurred during the Santonian and the latest Maastrichtian. From Morocco to Oman, most sedimentary basins were folded and inverted at these times. The Santonian event resulted from onset of the collision between the African-Arabian and Eurasian plates. New stress-fields favoured NE-SW extension along the African plate margin, generating or rejuvenating some rifts, e.g. in the Euphrates trough and in the Libya-Tunisia region (northwestern Sirt, Pelagian Sea). Rifting and magmatism continued in these regions into the Paleocene. During the Mesozoic, therefore, the northern margin of the African-Arabian plate registered both rifting resulting in the oceanization of the Tethys and rifting resulting from the initiation of the closure of the Tethys. The intraplate domain exhibited echoes of the tectonic events affecting the margin.