116 



S. OHTSUKA, G.A. BOXSHALL AND H.S.J. ROE 



minute spinules and row of long setules proximally (almost 

 missing in Fig. 4D); endopod rudimentary, 1-segmented, with 

 2 plumose setae of unequal lengths; exopod 5-segmented, 

 almost completely separate, first to fourth segments each 

 bearing 1 seta, terminal segment with 2 setae, one of which 

 thinner and shorter than other; second segment with patch of 

 minute spinules. 



Maxillule (Figs 4E,F,5A): praecoxal arthrite with 5 stout 

 spines, 2 of which (Fig. 4F) bearing 2 rows of strong spinules, 

 and 1 process, patch of long setules, and numerous minute 

 spinules of various sizes along inner margin and patch of fine 

 prominences along outer margin; coxal epipodite with 6 

 setae; coxal endite with elongate, spinulose seta terminally; 

 basis carrying minute enditic seta and row of long, fine setules 

 along inner margin; endopod rudimentary, 1-segmented, 

 bearing 2 spinulose setae of unequal lengths distally; exopod 

 lamellar, having 3 long, plumose setae distally. 



Maxilla (Fig. 5B) stout; first praecoxal endite with 2 

 spinulose setae and vestigial element; second praecoxal and 

 both coxal endites each carrying 2 spinulose setae; basal 

 endite bearing long, subterminal spine with 2 rows of spinules 

 medially; endopod 4-segmented, first segment with 1 spinu- 

 lose seta, second to fourth segments having 3, 2 and 2 long, 

 spinulose setae, respectively. 



Maxilliped (Figs 5C,6A-C) elongate; syncoxa with 1 medial 

 and 2 subterminal setae and patch of fine spinules subtermi- 

 nally; basis bearing 2 patches of spinules proximally and 

 midway along inner margin and 2 spinulose subterminal 

 setae; endopod 6-segmented, first segment incompletely 

 fused with basis, first to sixth segments carrying 1, 4, 4, 3, 3, 

 and 4 setae, respectively; innermost seta on fourth and fifth 

 segments relatively long; sixth with setae a and b well 

 developed, seta c chitinized, bearing row of simple spinules 

 along inner margin, seta d long, with inner row of simple 

 spinules. 



Leg 1 (Fig. 6D); second endopod segment produced at 

 outer angle; third endopod segment produced distally into 

 acute process, with 2 outer lateral spines and terminal plu- 

 mose seta; first exopod segment produced near outer angle; 

 second and third exopod segments produced at outer angle. 

 Leg 2 (Fig. 6E) and leg 3 (Fig. 6F-I) similar; outer angle of 

 second endopod segment acutely produced; third endopod 

 segment with 4 inner setae. Third legs with several aberra- 

 tions: extra spine present on each of first (Fig. 6F) and third 

 exopod segments (Fig. 6F,H); extra seta on first (Fig. 6H) 

 and second endopod segments (Fig. 6F); fewer seta on third 

 endopod segment (Fig. 6F); both rami extremely abnormal 

 (Fig. 61). Leg 4 (Fig. 6J): basis with small plumose seta near 

 base of exopod on posterior surface; terminal endopod 

 segment with 3 inner setae. 



Leg 5 (Fig. 6K,L): both legs almost symmetrical; right and 

 left coxae incompletely separate from intercoxal sclerite; 

 basis with relatively narrow base, bearing plumose seta at 

 outer angle; endopod small, 1-segmented, distinctly separate 

 from basis, with inner medial and terminal plumose seta; 

 exopod indistinctly 3-segmented, each almost fused, first and 

 second segment with serrate spine at outer angle, third with 2 

 terminal and 1 lateral spines. 



Male. Unknown. 



Variability. The paratypic females have aberrant third legs 

 (Fig. 6F,H,I). Both paratypes have 4 outer spines on the third 

 exopodal segment of leg 3, but it is likely that the segment 

 normally has 3 outer spines, because the males of Crassari- 



etellus sp. and other arietellids carry only 3 spines on this 

 segment. An additional spine on the first exopodal segment 

 of leg 3 has also been reported in specimens of some 

 shallow-water hyperbenthic and cave-dwelling species of the 

 calanoid family Pseudocyclopiidae (Scott, 1894; Fosshagen & 

 Iliffe, 1985). Some females of Paracyclopia naessi Fosshagen, 

 1985 had 2 outer spines on the first exopodal segment of leg 3 

 (Fosshagen & Iliffe, 1985) and this segment of the same leg in 

 Pseudocyclopia crassicornis Scott, 1892 was figured with 2 

 spines (Scott, 1892). 



It is interesting to note that it is the same segment of the 

 same leg which carried the extra spine in both Crassarietellus 

 and pseudocyclopiids. The presence of a seta on the outer 

 margin of the second endopodal segment of leg 3 (Fig. 6F) is 

 unique for the Calanoida. Elsewhere in the Copepoda such a 

 seta has only ever been found in the two superornatiremid 

 harpacticoids figured by Huys & Boxshall (1991). 



Remarks. The male of C. huysi is unknown. Crassarietellus 

 sp. described below, which was erroneously considered to be 

 the male of Sarsarietellus (= Scottula) abyssalis (Sars, 1905), 

 is similar to C. huysi except in sexual dimorphic characters, 

 but is smaller than C. huysi. Considering that the locality of 

 Crassarietellus sp. (38°02'N, 10°44'W) is near the type locality 

 of C. huysi (20°18.5'N, 21°41.2'W-20°20.8'N, 21°53.0'W), it 

 is possible that this male can be assigned to C. huysi. 



Crassarietellus sp. (Figs 7-8) 



Material examined. d\ Zoological Museum, University 

 of Oslo, Catalog No. F5445-5446, labeled as Scottula abyssa- 

 lis G.O. Sars. 



Body length. 2.8 mm (after Rose, 1933). 



Description. Integument of urosome and appendages pit- 

 ted as in Crassarietellus huysi. Left antennule (Fig. 7A-C) 

 geniculate between ancestral segments XX and XXI, fringed 

 with setules along posterior margins of segments I-X, trans- 

 verse row of setules on each of segments IV to VIII; fusion 

 pattern and armature as follows: I-IV-9 + 4 aesthetascs, V-2 

 + aesthetasc, VI-2 + aesthetasc, VII-2 + aesthetasc, VIII-2 

 + aesthetasc, IX-2 + aesthetasc, X-2 + aesthetasc, XI-2 + 

 aesthetasc, XII-2 + aesthetasc, XIII— 2 + aesthetasc, XIV-2 

 + aesthetasc, XV-2 + aesthetasc, XVI-2 + aesthetasc, 

 XVII-2 + aesthetasc, XVIII-2 + aesthetasc, XIX-1 + 

 aesthetasc + 2 processes, XX-2 + process, XXI-XXIII-1 + 

 aesthetasc + 2 processes, XXIV-XXVIII-12 + 2 aesthetascs; 

 segment XXV incompletely fused with XXVI. Sutures 

 between segment I to IV weakly visible. Right antennule as in 

 female of Crassarietellus huysi. 



Antenna (Fig. 7D): basis with serrate inner seta; endopod 

 2-segmented, first segment with short, inner seta at three 

 quarters length and numerous spinules subterminally, second 

 segment with 3 inner setae of unequal lengths and 5 setae 

 terminally, covered almost entirely with spinules; exopod 

 indistinctly 10-segmented, eighth segment fringed with 

 minute spinules along both sides; setal formula of exopod as 

 follows: 0,0,0,1,1,1,1,1,0,3. 



Mandibular gnathobase (Fig. 7F) with 3 stout teeth, dor- 

 salmost of which bifid at tip; tuft of long setules present near 

 base of palp. Mandibular palp (Fig. 7E): basis elongate, 

 furnished with numerous minute spinules and row of long 

 setules along inner margin; endopod rudimentary, 

 1-segmented, bearing 2 unequal setae; seta on first exopod 



