Bull. nut. Hist. Mus. Land. (Zool.) 66(2): 1 67-170 



Issued 30 November 2000 



A new species of Sigambra (Polychaeta, 



Pilargidae) from the abyssal plains of the 



NE Atlantic yy £3 3 ° ° ^ % • * 



GORDON L J PATERSON AND ADRIAN G. GLOVER 



Polvchaete Research Group, Department of Zoology, The Natural Histo?y Museum, London SW7 5BD, UK. 



INTRODUCTION 



During an intensive study of the benthic communities of the 

 NE Atlantic abyssal plains (Rice et al. 1994), a new species of 

 Sigambra was identified. It was conspicuous in being one of the 

 more abundant species and certainly the dominant predator. The 

 species was widespread, being recorded from study sites from the 

 Cap Verde Abyssal Plain in the south to the Porcupine Abyssal Plain 

 in the north. 



MATERIAL AND METHODS 



All specimens were collected using a modified United States Naval 

 Electronics Laboratory, spade box corer (SBC). Samples from the 

 Porcupine, Madeira and Cape Verde Abyssal Plains were sectioned 

 horizontally into 0-1 cm, 1-3 cm and 3-5 cm layers and processed 

 through a number of sieves - 1, 0.5 and 0.3 mm. Samples from the 

 Tagus Abyssal Plain were taken with a vegematically modified box 

 corer and only the inner nine subcores were processed through a 0.3 

 mm sieve. 



Material studied 



Specimens have been deposited in a number of taxonomic institu- 

 tions and corresponding registration numbers are given below. 

 Abbreviations: AM - The Australian Museum, Sydney; LA - Los 

 Angeles County Museum of Natural History; MNHN - Museum 

 National d'Histoire Naturelle, Paris; BMNH - The Natural History 

 Museum, London: NMNH - National Museum of Natural History, 

 Smithsonian Institution; NMS - The National Museums of Scot- 

 land; NMW - The National Museum of Wales; ZH Zoologisches 

 Institut und. Museum, Hamburg; ZMUC - Zoological Museum, 

 Copenhagen. 



Holotype: Porcupine Abyssal Plain Challenger II Criuse 111: 

 53201#29 48°51.5' N 16°29.6' W, 4844 m, sediment layer 1-3 cm 

 0.5mm sieve, 14/4/1994 (BMNH 2000. 1852). 

 Paratypes: Porcupine Abyssal Plain the following samples cen- 

 tred on 48°50' N 16°30' W in 4850 m: 



Discovery Cruise 185: 11908#18: l-3cm 0.3 mm sieve 1 ind. 28/8/ 

 1989. 



Challenger II Cruise 79: 52701#5: 1-3 cm, 0.3mm sieve 4 ind.; 1- 

 3cm 0.5mm sieve 2 ind (NMSz: 2000.214).16/5/1991. 

 52701#9: 1-3 cm 0.5mm 1 ind (ZMH). 17/5/1991. 

 52701#25: 1-3 cm 0.3mm sieve 1 ind.(MNHN-POLY 53); 0-1 cm 



0.5 mm sieve 1 ind (NMW.Z: 2000.070).; 3-5 cm 0.5mm sieve 2 



ind (NMNH 186794). 20/5/1991; 

 52701#29: 1-3 cm 0.3 mm sieve 1 ind. (AM); 1 ind. (ZMUC-POL- 



1013 21/5/1991. 



52701#47 1-3 cm 0.3 mm sieve 1 ind. (LA) 21/5/1991. 

 Challenger Cruise 111: 53201#23 l-3cm0.3mm 1 ind. 13/4/1994; 



53201#26 1-3 cm 0.3 mm sieve 1 ind., 1-3 cm 0.5 mm sieve 2 



ind., 3-5 cm 0.3 mm 1 ind. 14/4/1994; 

 53201 # 29 1-3 cm 0.25 mm sieve 1 ind., 1-3 cm 0.5 mm sieve 1 



ind.. 3-5 cm 1 mm sieve ind. 14/4/1994; 

 53205#2 0.3 mm 0-1 cm sieve 1 ind., 3-5 cm 0.5 mm sieve 1 ind., 



18/4/94. 



Tagus Abyssal Plain centred on 38°N 11°W 5035 m: Discovery 

 Cruise 186: SBC365 3 ind. 26/9/1989; SBC366 1 ind. 26/9/1989; 

 SBC367 5 ind. 26/9/1989; SBC368 5 ind., SBC369 2 ind. 27/9/ 

 1989; SBC371 2 ind. 28/9/1989. 



Madeira Abyssal Plain centred on 31°10' N 21°10 W 4985m: 

 Discovery Cruise 194: 12174#35: 1-3 cm 0.3 mm sieve 2 ind.: 1-3 

 cm 0.5 mm sieve 1 ind.; 3-5 cm 0.5 mm sieve 3 ind. 21/8/1990. 

 12174#43: 1-3 cm 0.3 mm 1 ind. 22/8/1990. 

 12174#53: 1-3 cm 0.3 mm sieve 2 ind. 23/8/1990 

 12174 #60: 1-3 cm 0.3 mm sieve 1 ind. 24/8/1990. 

 1 2 1 74#80 0— I cm 0.3 mm sieve 1 ind.; 5-10 cm 0.5 mm sieve 1 ind. 

 28/8/90. 



Cape Verde Abyssal Plain centred on 20°N 30°W 4500-4600 m: Dis- 

 covery Cruise 204: 12600#32O-l cm0.3 mm sieve 1 ind. 6/10/1994. 



In addition the following material was examined: Sigambra bidentata 

 Britaev & Saphronova, 1981 Natural History Museum Polychaete 

 Collection Z 1986: 178-183 (5 paratypes), Vityaz Stn 7488 38° 

 41'N:133°45'E 1550 m Sea of Japan. Sigambra gracilis Britaev & 

 Saphronova, 1981 ZR 1986. 184-1 85 (2 paratypes), Vostok Bay, Sea 

 of Japan. Sigambra phuketensis Licher and Westheide, 1997 Z1993. 

 15-16 (2 Paratypes), Bang Tao, W. Phuket Island, Thailand. 



TAXONOMIC ACCOUNT 



Family PILARGIDAE 



Genus SIGAMBRA O.F.Muller, 1858 



Species S. magnuncus sp. nov. 



(Figs 1-5) 



Description 



Holotype: Length 3.7 mm for 33 chaetigers, greatest width of 



body 0.3 mm. 



Paratypes: Range from length 0.5 mm for 13 chaetigers to 10.5 



mm for 50 chaetigers, number of segments depends on size of 



individual. (Fig. 5). 



Body unpigmented; slightly flattened anteriorly, but becoming 

 more rounded posteriorly; anterior chaetigers widest. 



© The Natural History Museum, 2000 



