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The Marine Flora and Fauna ofHong Kong and Southern China IV (ed. B. Morton). Proceedings of the Eighth International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 2-20 Aprill995. Hong Kong: Hong Kong University Press, 1997. DISCINISCA STELLA (GOULD, 1860): AN INTERTIDAL INARTICULATE BRACHIOPOD FROM THE CAPE D'AGUILAR MARINE RESERVE, HONG KONG Elizabeth Harper Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, U.K. ABSTRACT Discinisca stella is a small inarticulate brachiopod which lives attached firmly to boulders both sub-tidally and intertidally within Lobster and Telegraph bays. Although the presence of this species in Hong Kong has been noted by a number of early brachiopod workers its presence has been relatively ignored by more recent zoologists. The purpose of this paper is to outline the occurrence of Discinisca stella at Cape d' Aguilar and to describe its hardpart morphology. Since inarticulate brachiopods rarely receive attention, there is considerable scope for further study of this animal and, in particular, its role as a space competitor and its vulnerability to the many durophagous predators which co-habit the boulder fields are worthy of consideration. INTRODUCTION Following the mass extinction which occurred at the close of the Permian (248 million years ago), brachiopods never again enjoyed the abundance and diversity that they had experienced during the Palaeozoic. Then, they were key members of shallow marine communities while today there are few living brachiopods belonging to a much smaller number of orders. Those which have been studied most intensively are from temperate and polar latitudes such as those off Scotland, New Zealand and Antarctica (James et ai. 1992). As a consequence of their low diversity and relative scarcity in Recent faunas the study of the Brachiopoda has been chiefly the preserve of palaeontologists. In recent years, however, there has been an increase in the knowledge of Recent brachiopods and according to James et ai. (1992) the number'Of genera of recognised living brachiopods has doubled since Rudwick (1970). It is becoming increasingly clear that Recent brachiopods should not be regarded as 'pathetic....living fossils eking out an existence in caves' (Ward 1995, p.26) but as an interesting group which in some parts of the world are dominant space occupiers of hard substrata (La Barbera 1985). 236 E. HARPER Brachiopods from the South China Sea have been collected and reported upon since the middle of last century (Gould 1860; Davidson 1886; Dall 1930; Richardson, et al. 1989). With the exception of Richardson et al. (1989), however, there has been little recent interest and indeed that paper contains only the briefest descriptions of the taxa present in an already existing collection. In Hong Kong, the most conspicuous brachiopod is the burrowing inarticulate Lingula anatina Lamarck which inhabits protected sand flats such as Hoi Sing Wan (Morton and Morton 1983). This paper reports briefly on the occurrence and the hardpart morphology of another inarticulate brachiopod found in Hong Kong. Discinisca stella is a small epifaunal brachiopod which lives intertidally and subtidally at the Cape d' Aguilar Marine Reserve as well as elsewhere in Hong Kong. This species has been noted by earlier workers but these provide only brief descriptions of the taxon and few illustrations. TAXONOMY BRACHIOPODA DUMERIL, 1806 INARTICULATA HUXLEY, 1869 ACROTRETIDA KUHN, 1949 DISCINOIDEA GRAY, 1840 DISCINIDAE GRAY, 1840 Discinisca Dall, 1871 Discinisca stella (Gould, 1860) The species was first collected by W. Stimpson from Hong Kong (further locality details appear not to be available) and described subsequently by Gould (1860) [not Gould (1862) as cited by Richardson et al. (1989)] as Discina stella, although he did not provide illustrations. The first illustration appears to be that given by Reeve (1862) in his Conchyliorum Iconica where he referred to it as Orbicula stella. In 1871 Dall erected the sub-genus (now regarded as a genus by (Stenzel 1964)) Discinisca, with D. lamellosa (Broderip) as the type. In that same paper Dall transferred Discina stella into his new genus but without either further illustration or species diagnosis. Subsequent illustrations and a diagnosis of Discinisca stella were provided by Davidson (1886). The material collected and used for this study has been deposited in the brachiopod collection of the Palaeontology Department, The Natural History Museum, London and at the Swire Institute of Marine Science, the University of Hong Kong. OCCURRENCE Dall (1920) lists specimens of Discinisca stella, including the type, from the collections of the United States National Museum as having been...

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