46 



R. HUYS AND J. M. GEE 



A detailed redescription of A. sibirica and new illustrations of D. typica, P. longisetosa, P. longipes and B. 

 longifurca are provided. 



Intersexuality in copepods and the possible phylogenetic relationships of Danielssenia, Psammis, Fladenia, 

 Archisenia gen. nov. and Bathypsammis gen. nov. are briefly discussed. 



A key to the genera of the Paranannopidae is presented. 



INTRODUCTION 



Throughout its taxonomic history up to the late 1980s, the 

 genus Danielssenia Boeck, 1872 has served as a repository to 

 accommodate different kinds of 'tachidiid' harpacticoid cope- 

 pods, in so far that the distinction between this genus and 

 Psammis Sars, 1910 almost became no longer tenable (Wells, 

 1965, 1967). Gee (1988a) pointed out that differences in 

 mandibular gnathobase structure, possibly reflecting different 

 diets, could indicate that both genera are trophically isolated, 

 but admitted that perhaps more solid morphological evidence 

 is necessary to maintain generic distinction. 



The criteria applied by most workers to allocate newly 

 discovered species to Danielssenia generally had no phyloge- 

 netic significance as they were mainly based on plesiomorphic 

 character states (i.e. PI not modified) which are diagnostic of 

 a wider group of families. Virtually no effort has been made 

 to correctly assess the sexual dimorphism on the swimming 

 legs and very little information on detailed mouthpart struc- 

 ture has been documented. Both categories of characters 

 have nevertheless proved to hold a high phylogenetic infor- 

 mation content that can be used to determine relationships 

 within the Danielssenia-Psammis core group of genera (Gee 

 & Huys, 1990, 1991; Huys & Gee, 1992, in press). 



The impact of Lang's (1944, 1948) classification of the 

 Tachidiidae also caused people to lose sight of the relation- 

 ships of this core group with taxa beyond the family bound- 

 aries. The fact that his artificial subdivision into three 

 subfamilies constrained the development of alternative phy- 

 logenetic scenarios for a long time is illustrated by the 

 ongoing discovery and description of numerous new species 

 of Paranannopus Lang, 1936 (placed in the Cletodidae and 

 subsequently in the Paranannopidae) and Danielssenia 



(placed in the Thompsonulinae, Tachidiidae) in the post- 

 Langian era without any recognition of the close relationship 

 between these two taxa. Huys & Gee (1990) inevitably had to 

 break down the concept of the Thompsonulinae before they 

 could re-allocate the 'danielsseniid genera' to the Paranan- 

 nopidae. This group of genera essentially represents the 

 continental shelf lineage of the family with a few species that 

 secondarily explored deeper habitats (e.g. Leptotachidia iber- 

 ica Becker, 1974). Its affinity to the predominantly deepwater 

 group, containing Paranannopus and Cylindronannopus 

 Coull, 1973, has recently been supported by the redescription 

 of Fladenia Gee & Huys, 1990, a possible 'missing link' 

 between both lineages (Gee & Huys, 1990). 



This paper is the final contribution to a revision of the 

 genus Danielssenia, including the allocation of the sibirica- 

 group to a new genus Archisenia, thus reducing the number 

 of species previously referred to the genus from 14 to four 

 (Table 1). It also presents a revision of the other major genus 

 Psammis, resulting in the proposal of a new genus Bathyp- 

 sammis. With the revision of these taxa the establishment of 

 novel genera draws to a close and, accordingly, a key to 

 genera of the Paranannopidae is presented. 



MATERIALS AND METHODS 



Before dissection, the habitus was drawn and body length 

 measurements were made from whole specimens temporarily 

 mounted in lactophenol. Specimens were then dissected in 

 lactic acid, the parts mounted in lactophenol and the prepara- 

 tions sealed with glyceel® (BDH Chemicals Ltd, Poole, 

 England). All drawings of the specimens were prepared using 

 a camera lucida on a Leitz Dialux 20 or Leitz Diaplan 



Table 1 Re-allocation of species previously referred to Danielssenia Boeck, 1872. 



Species previously referred 

 to Danielssenia 



Current status 



Reference 



typica Boeck, 1872 

 fusiformis sensu (Sars, 1910) 

 quadriseta Gee, 1988 

 reducta Gee, 1988 

 similis Chislenko, 1978 

 sibirica Sars, 1898 

 stefanssoni Willey, 1920 

 fusiformis Brady, 1880 

 perezi Monard, 1935 

 paraperezi Soyer, 1970 

 eastwardae Coull, 1971 

 robusta Sars, 1921 

 intermedia Wells, 1965 

 spinipes Wells, 1967 

 minuta Coull, 1969 



Danielssenia typica Boeck, 1872 

 Danielssenia typica Boeck, 1872 

 Danielssenia quadriseta Gee, 1988 

 Danielssenia reducta Gee, 1988 

 Danielssenia similis Chislenko, 1978 [sp. inq.] 

 Archisenia sibirica (Sars, 1898) comb. nov. 

 Archisenia sibirica (Sars, 1898) comb. nov. 

 Jonesiella fusiformis Brady , 1880 

 Jonesiella fusiformis Brady , 1880 

 Jonesiella fusiformis Brady , 1880 

 Jonesiella eastwardae (Coull, 1971) comb. nov. 

 Fladenia robusta (Sars, 1921) comb. nov. 

 Fladenia robusta (Sars, 1921) comb. nov. 

 Afrosenia spinipes (Wells, 1967) 

 Sentiropsis minuta (Coull, 1969) 



Gee (1988) 



Gee (1988), present account 



Gee (1988) 



Gee (1988) 



present account 



present account 



present account 



present account 



present account 



Huys & Gee (1992), present account 



Huys & Gee (1992), present account 



present account 



Gee & Huys (1988), present account 



Huys & Gee (in press) 



Huys & Gee (in press) 



