ALBERT

Description: Although motion between Arabia and Africa is presently occurring along the entire length of the Red Sea, the morphology and tectonics that result from this motion vary greatly along its length. South of 21°N, the main trough is bisected by a deep axial trough which has formed by sea-floor spreading during the past 4 m.y. and is associated with large-amplitude magnetic anomalies and high heat flow. North of 25°N, an axial trough is not present and the floor of the main trough has an irregular faulted appearance. The magnetic field in the north is characterized by smooth low-amplitude anomalies with a few isolated higher amplitude magnetic anomalies commonly associated with gravity anomalies and in many places probably due to intrusions. Between these regions, the axial trough is discontinuous with a series of deeps characterized by large-amplitude magnetic anomalies alternating with shallower intertrough zones which lack magnetic anomalies. It is argued that the different regions represent successive phases in the rifting of a continent and the development of a continental margin. An initial period of diffuse extension by rotational faulting and dike injection over an area perhaps 100 km (60 mi) wide is followed by concentration of extension at a single axis and the initiation of sea-floor spreading. The main trough in the southern Red Sea, away from the deep axial trough, formed during the Miocene by the same processes of diffuse extension that are still active in the northern Red Sea. This model explains the available geologic and geophysical data and reconciles previous models for the formation of the Red Sea which emphasize either the evidence for considerable motion between Arabia and Africa or the evidence for down aulted continental crust beneath much of the Red Sea. The initial pre-sea-floor spreading stage results in considerable extension (160 km or 100 mi) at 25°N in the Red Sea), can last for several tens of millions of years, and is an important factor in the development of the continental margin. Such an extended phase of rifting and diffuse extension must be taken into account in studies of sedimentation, subsidence, and paleotemperatures.

Description: North Atlantic deep sea cephalopods caught in research nets (mouth opening of9 m2) and I arge commercial trawls are compared with those eaten by Sperm Whales. 1t is shown that at three latitudes the nets and whales sample cephalopods very differently. Research nets are biased towards collecting small species and young specimens of several families, principally gonatids, cranchiids, enoploteuthids and onychoteuthids, while sperm whales are biased towards catching much !arger cephalopods, particularly histioteuthids. Commercial trawls tend to bridge the gap in size of cephalopods selected by research nets and whales but where comparisons are possible they have a bias towards catching enoploteuthids. The contribution by numbers and weight of different cephalopod families to the cephalopod fraction of the diet of sperm whales throughout the world is reviewed. A detailed study of Antarctic cephalopods in the diet of large predators including cetaceans, seals and birds indicates areas where more knowledge is required to make accurate estimates of the biomass of Antarctic cephalopods consumed. The value of direct studies of food webs for quantitative consideration of particular cephalopod taxa is demonstrated and discussed.

Description: This paper reviews the current status of systematics of Recent cephalopods (squids, cuttlefishes, octopuses and nautiluses) on a world-wide basis. It includes lists of recent revisionary publications (1960-1981), and revisions in progress. Problems that impede progress in cephalopod systematics are discussed, including the taxonomic and geographic complexity of the group, lack of comprehensive collections and well preserved specimens, scarcity of classical studies, scattered literature, and lack of funding for research and education. The situation in Australia is cited as an example of the status of cephalopod systematics in most other regions of the world. A list of Australian species in four major families (Sepiidae, Loliginidae, Ommastrephidae, Octopodidae) is presented, as is a bibliography of the cephalopod biological literature of the Australian region. Recommendations are given in an effort to improve the status of cephalopod systematics and consequently to provide information required in other fields (e.g., biomedical research, behavior, ecology, parasitology, fisheries biology): (I) recognition of need for research and education and for increased funding to support them; (2) training and development of regional (geographic) specialists as well as taxon-oriented (world-wide) specialists; (3) support and production of keys to identification, catalogues of important collections, and revisions and monographs; (4) establishment of national, regional, and world-wide authoritative reference collections; (5) designations of four major families of cephalopods in critical need of comprehensive systematic revision (Sepiidae, Loliginidae, Ommastrephidae, Octopodidae)