92 



R. HUYS AND S. OHTSUKA 



fine spinules. A distinct, ventrally directed, spinous process is 

 located at the ventral midline between the maxillipedal 

 syncoxae and the coxae of the first leg (Fig. 3A). 



P2-P4 (Figs. 3B-D) with 3-segmented exopods and 

 1-segmented endopods. Intercoxal sclerites small, rectangu- 

 lar, bare (Fig. 3C). Spines of distal exopodal segment elon- 

 gate and slender in P3 and P4. Inner seta of P2 endopod 

 serrate and typically recurved (Fig. 3B). Inner margin of 

 endopod P3 with serrate seta and vestigial seta represented 

 by setule (see inset Fig. 3C). Distal spines of endopod pinnate 

 in P2-P3, bare in P4. Armature formula as follows: 





coxa 



basis 



exopod segment 



endopod segment 









1 2 



3 



1 2 



PI 



0-0 



1-1 



1-0; 1,2,0 





0-1; 0,1,1 



P2 



0-0 



1-0 



1-0; 1-0; 



1,11,0 



0,11,1 



P3 



0-0 



1-0 



1-0; 1-0; 



1,1,1 



0,1,2 



P4 



0-0 



1-0 



1-0; 1-0; 



1,1,1 



0,1,1 



Fifth legs (Figs. 4A, C) closely set together, no intercoxal 

 sclerite. Baseoendopod and exopod fused to form a single 

 plate with 2 secretory pores and 4 armature elements in total; 

 endopodal lobe represented by long, triangular, spinous 

 process without setae but with tiny spinules along proximal 

 outer margin and on posterior surface; exopod presumably 

 represented by weakly developed process bearing outer pin- 

 nate spine, inner slender seta and a vestigial seta in between. 

 Outer basal seta elongate and bare. 



Male. Body length measured from tip of rostrum to poste- 

 rior margin of caudal rami (Fig. 6A) 460 \im. Ornamentation 

 of body somites generally as in female; genital and first 

 abdominal somites separate, with spinulose hyaline frill each. 

 Sexual dimorphism in antennule, P3 endopod, P5, P6 and in 

 genital segmentation. Spermatophore not observed. 



Antennule (Figs. 6B-F) indistinctly 8-segmented, articulat- 

 ing on a small pedestal. Relative lengths of first two segments 

 as in female. Third and fourth segment (= ancestral segment 

 XIII) interdigitating as shown in Fig. 6C. Major geniculation 

 between segments 6 and 7. Segmental fusion pattern: I, 

 II-VIII, IX-XII, XIII, XIV-XVIII, XIX-XX, XXI-XXII, 

 XXIII-XVIII. Segment 6 with 1 modified flat spine and 1 

 setule, segment 7 with similar spine and 1 stubby pinnate 

 element. Armature formula: [1, 9, 5, 2, 4+ae, 2, 2, 9]. 



P3 endopod (Fig. 6G) 2-segmented. Proximal segment 

 unarmed. Distal segment drawn out into pinnate process 

 (derived from distal spine in $) with spatulate tip bearing 2 

 rows of denticles; inner margin with short pinnate seta and 

 minute setule. 



P5 (Fig. 4D). Relative position, shape and armature largely 

 similar to female except for the inner exopodal and outer 

 basal seta being distinctly shorter. Ornamentation of endopo- 

 dal lobe also slightly different with fewer spinules along the 

 proximal outer margin and tiny spinules along the inner 

 margin. 



Sixth pair of legs (Fig. 4E) positioned midventrally, sym- 

 metrical; inner distal corner with numerous minute spinules 

 and produced into a small process; armature consisting of 

 inner strong spine, outer slender seta and a vestigial setule in 

 between. 



Variability. An aberrant left P3 was noticed in the holo- 

 type $ (Fig. 3C). 



Etymology. The species name is derived from the Latin 

 inter, meaning between, and medius, meaning middle, and 

 refers to the intermediate position between S. galapagoensis 

 and the European species of the genus. 



Syrticola flandricus Willems & Claeys, 1982 (Figs. 

 5F-H) 



Material examined. 3 5 $ from off Walcheren, The Neth- 

 erlands, southern North Sea, 51° 57'25" N, 02° 40'45" E, 

 depth 44.5 m, coarse sandy sediment, 08 May 1991, coll. R. 

 Huys. One $ in alcohol deposited under reg. no. 1992.1077. 



The description given by Willems & Claeys (1982) is 

 detailed and therefore only a few corrections to the original 

 figures are noted here. 



Antenna. The exopod possesses only one seta as in S. 

 intermedius and 5. galapagoensis. The oblique suture line has 

 probably been mistaken for the lateral seta (compare Fig. 2D 

 with Fig. 2B in Willems & Claeys (1982)), and it is conceiv- 

 able that the same misinterpretation applies for S. mediterra- 

 neus (cf. Willems et ai, 1987: Fig. 3A). 



Mandible. The basis bears only one seta; the supernumer- 

 ary proximal 'setae' figured by Willems & Claeys are part of a 

 transverse row of long spinules running around the lateral 

 margin of the basis. 



Maxillule. The arthrite of the praecoxa has 6 marginal and 

 2 surface setae, the coxal endite 2 setae and the distribution 

 pattern of the palp setae is identical to 5. intermedius (Fig. 

 2G). 



Maxilliped. The endopodal claw bears an accessory setule 

 at its base. 



PI. A seta is located at the inner distal corner of the basis. 



P5. The armature of the exopodal lobe consists of an outer 

 spine, an inner seta and a setule in between (Fig. 5F). 



The genital field is basically the same as in S. intermedius 

 (Fig. 5G). 



REMARKS 



A single probably parthenogenetic female of a tantulocaridan 

 was found attached to the pleurotergite of the P3-bearing 

 somite of the holotype 2 of S. intermedius (Fig. 1A). The 

 specimen is about 160 \im long and is at an early stage of 

 development. The larval postcephalic trunk had been 

 sloughed already but no differentiating tissue could be 

 observed inside the sac. The male paratype was also infested 

 by a parthenogenetic female (Fig. 6A) which was larger 

 (235 jim) and attached to the pleurotergite of the genital 

 somite. Inside the sac a large number of small eggs of about 

 20-25 um in diameter is contained. Both tantulocaridan 

 stages most likely belong to an as yet undescribed species 

 which was found to infest harpacticoids belonging to at least 

 two other families (Huys et al., in preparation). Since only< 

 the head shield (Figs. 5D-E) is left for comparison this; 

 identification has to be considered provisional. 



