Marine Flora and Fauna of Hong Kong and Southern China IV

Pycnogonids (Arthropoda: Pycnogonida) from the Cape d'Aguilar Marine Reserve, Hong Kong

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 April 1995. Hong Kong: Hong Kong University Press, 1997. PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) FROM THE CAPE D'AGUILAR MARINE RESERVE, HONG KONG R. N. Bamber Fawley Aquatic Research Laboratories Ltd, Marine and Freshwater Biology Unit, Fawley, Southampton, Hampshire S045 ITW, U.K. ABSTRACT The pycnogonid material collected within the Cape d'Aguilar Marine Reserve, Hong Kong, in April 1995 is described, together with one specimen housed in the museum of the Swire Institute of Marine Science. The 38 specimens represented 6 species, including the first (topotypic) females of Tanystylum sinoabductus and a new species of Pycnogonum. Other than these two 'endemics', the species recorded show Indo-West Pacific distributions. A key to those species of Pycnogonum having auxiliary claws is given, together with a key to all species so far recorded from the shallow waters of Hong Kong, Korea and China. INTRODUCTION Morton and Harper (1995) describe the general features of the Cape d' Aguilar Marine Reserve, including its marine ecology, geology and topography. The present paper reports on the pycnogonid material collected at Cape d'Aguilar during April 1995. Previously only three pycnogonid species had been recorded from Hong Kong waters (Bamber 1992), Anoplodactylus glandulifer Stock, 1954, Tanystylum sinoabductus Bamber, 1992 and an unidentified juvenile Nymphon. Thirty-one species have been recorded from waters less than 70 m depth in the seas around Korea and the coast of China, although not including the two mentioned above (see Discussion). MATERIALS AND METHODS Between 11 and 19 April 1995, a range of habitats was sampled from within the proposed reserve. Bulk epifaunal, algal and sedimentary samples were rinsed with freshwater (to relax and partially anaesthetize the specimens) and sieved over a 0.5 mm mesh, before being examined under x16 magnification. Additional specimens were kindly supplied by colleagues. All pycnogonid specimens were removed and fixed in 5% saline formalin. 144 R. N. BAMBER RESULTS Thirty-eight pycnogonid individuals were recorded representing six species, of which only one was known previously from Hong Kong waters (but of which the female is recorded here for the first time), a further two were previously known from waters off either Korea or China, and one is new to science. Type and other specimens are lodged at the National Museum of Wales, Cardiff (Accession numbers prefixed NMW.Z); representative material is lodged at the Swire Institute of Marine Science (SWIMS). PYCNOGONIDA AMMOTHEIDAE DOHRN, 1881 Achelia echinata Hodge, 1864 Achelia echinata, Utinomi 1954, 11-14, Figures 4-5. Type-locality: United Kingdom (North Sea) Material: 1~ , from community fouling a discarded monofilament fishing net, depth between 0 and 14 m (the seabed), northwest of Kau Pei Chau, 13 April 1995 (SWIMS No SWIMS-CRU-95-003). A widespread species, predominantly from shallow waters throughout the northeast Atlantic and Mediterranean, also from the Virgin Islands, the Azores, Japan, Korea and China, with questionable records from Alaska and San Francisco Bay (Hilton 1943). Forms from Japan, the Sea of Japan off Russia and from China have been named as the subspecies Achelia e. japonica (Ortmann 1890), A. e. orientalis (Losina-Losinsky 1933) and A. e. sinensis (Lou 1936) respectively, but the relevance of these subspecies is highly questionable. This species is known to feed on bryozoans and algae (Wyer 1972; Bamber and Davis 1982). Ammothella appendiculata (Dohrn, 1881) Figure lA Ammothea appendiculata Dohrn 1881, 152-155, Plate VII. Type locality: Gulf of Naples (Mediterranean) Material: 1 juvenile, amongst heterogeneous shell-sand in silt, 5 m, 11 April 1995; 1 subadult, from community fouling a discarded monofilament fishing net, depth between oand 14 m (the seabed), 13 April 1995 (SWIMS No SWIMS-CRU-95-002); 1 subadult, amongst infralittoral clean shell gravel, ca 0 m depth, 17 April 1995 (NMW.Z.1995.042.1); all northwest of Kau Pei Chau. While Ammothella indica Stock, 1954 is the commoner Indo-West Pacific species of this sibling pair, the present specimens have no ornamentation of the lateral processes other than a single, pointed posterodorsodistal spine, very few blunt spines on the femur, lateral processes which are not especially slender, and chelifore scape article 2 is 1.5 PYCNOGONIDS OF CAPE D' AGUILAR 145 ~B Fig. 1. A, Ammothel/a appendiculata, trunk lateral; B, Pigrogromitus...