NEW SPECIES OF SYRTICOLA FROM JAPAN 



85 



dimorphism endopod P3 involving fusion of distal spine to 

 segment; (ix) P5 exopod with 3 elements in both sexes. There 

 is little evidence that Arenopontia and Pararenopontia share a 

 close relationship with this core group, however pending a 

 revision of these genera it is preferable to retain them in the 

 Leptopontiinae. 



Syrticola Willems & Claeys, 1982 



Diagnosis (amended). Leptopontiinae. Body cylindrical, 

 but not particularly vermiform. Hyaline frill of all body 

 somites incised. Antennule 6- or 7-segmented in 9- Maxilla 

 with one syncoxal endite. Midventral spinous process ante- 

 rior to intercoxal sclerite of PI. PI exopod 2-segmented. 

 Distal segment PI endopod with 1 geniculate seta and 1 claw. 

 Distal segment P3-P4 exopods with 1 outer spine. P2-P4 

 endopods 1-segmented in 9> P3 endopod 1- or 2-segmented 

 and sexually dimorphic in cf. P5 with fused baseoendopod 

 and exopod in both sexes; endopodal lobe drawn out into 

 triangular process with 0-1 seta, exopodal lobe a tubercle with 

 3 elements. Genital apertures not fused in 9- Anal opercu- 

 lum with a series of small spinous processes or one large 

 median spike. Caudal ramus seta III inserted proximal to seta 

 V. 



TYPE SPECIES. Syrticola flandricus Willems & Claeys, 1982 



Other species. S. trispinosus (A. Scott, 1896), S. galapa- 

 goensis (Mielke, 1982), 5. mediterraneus Willems et al. , 1987, 

 5. intermedius sp. nov. 



Syrticola intermedius sp. nov. (Figs. 1—4, 5A-C, 6) 



Material examined. Holotype 9 dissected on 8 slides, 

 deposited under reg. no. 1992.1075. Paratype a" dissected on 

 6 slides, deposited under reg. no. 1992.1076. Drawings based 

 on the paratype are Figs. 2E-F, 4D-F, 5A-C, 6A-G; all 

 others were drawn from the holotype 9 • 



Female. Body length measured from tip of rostrum to 

 posterior margin of caudal rami 485 um (Figs. 1A-B). Maxi- 

 mum width 75 [im measured at rear margin of cephalothorax. 

 Integument pitted. Pleural areas of cephalothorax not well 

 developed so that appendages are clearly exposed in lateral 

 aspect (Fig. IB). Posterior margin of body somites (except 

 cephalothorax and anal somite) fringed dorsally and laterally 

 with finely incised hyaline frill; this frill also present ventrally 

 on genital double-somite and abdominal somites (Figs. IB, 

 4A-B). Abdominal somites also with transverse spinular row 

 in anterior half which is usually concealed beneath the 

 hyaline frill of the preceding somite as shown in Fig. 5A. 



Rostrum triangular, with 2 delicate sensillae (as in male, 

 Fig. 6B). 



Genital double-somite (Fig. 4B) about as long as wide; 

 original segmentation not marked by any external or internal 

 cuticular structure; anterior margin with 2 transverse spinular 

 rows. Genital apertures located in anterior quarter of genital 

 double-somite, closely set together but separate and each 

 closed off by small operculum derived from sixth leg; no 

 armature observed but posterior margin of operculum with 

 minute spinous processes and a circular scar at the outer 

 distal corner (probably indicating insertion site of long seta as 

 in 5. flandricus, cfr. Fig. 5G). Copulatory pore located far 

 anteriorly between genital apertures (arrowed in Fig. 4B). 

 Seminal receptacles not confirmed. Paired widely separated 

 secretory pores at about 2/5 distance from anterior margin. 



Anal somite (Figs. 1A-B; 4A; 5A-B) with dorsal opercu- 

 lum drawn out into median, posteriorly directed, spike; 

 process about as long as anal somite proper; ventral posterior 

 margin spinulose medially. 



Caudal rami (Figs. 4A; 5A-B) divergent; outer distal 

 corner drawn out into backwardly directed, acutely recurved, 

 spinous process; with 7 setae; seta I minute, setae II and III 

 located anterior to seta I, seta IV tiny and located between 

 spinous process and large seta V, seta VII long and tri- 

 articulate at base, seta VI minute. 



Antennule (Fig. 2A) 7-segmented, articulating on a small 

 pedestal as in the male (Fig. 6B); slender, anteriorly directed 

 (Fig. 1A); first segment extremely elongate, about 4 times as 

 long as maximum width, with 1 short seta distally; aesthetasc 

 on fourth segment fused basally to long seta; distal 2 setae of 

 last segment fused basally. All setae bare; setal formula: [1, 

 8, 3,2+ae, 1,2,9]. 



Antenna (Figs. 2B-D). Coxa small, not ornamented. Basis 

 and proximal endopod segment fused to form allobasis, 

 original segmentation marked by internal chitinous rib anteri- 

 orly and incomplete suture line posteriorly near exopod; basis 

 with serrate seta located on inner lateral surface; exopod 

 small, 1-segmented, with 1 small, apical seta; free endopod 

 articulating with allobasis at right angle (Fig. IB), lateral 

 margin with 2 spines, distal margin with 1 pinnate spine and 4 

 geniculate setae, the largest of which is fused basally with 

 vestigial seta and bearing coarse spinule at about midway. 



Labrum (Fig. 5C) a ventrally projected, elongate, membra- 

 nous outgrowth, distinctly tapering distally. Paragnaths small 

 membranous lobes. 



Mandible (Figs. 2E-F) with conspicuous coxa, drawn out 

 to form a slender, stylet-like gnathobase bearing small teeth 

 and a long serrate seta near the apex. Palp elongate, 

 2-segmented; proximal segment representing basis, slightly 

 sigmoid, swollen in distal half, with 1 seta and spinular row; 

 distal segment representing endopod, with 2 lateral and 3 

 apical setae. 



Maxillule (Fig. 2G). Praecoxa with large, cylindrical arth- 

 rite bearing 2 anterior surface setae and 6 setae along the 

 distal margin; coxal endite with 2 setae; palp representing 

 fused basis and rami; exopod, endopod, proximal and distal 

 basal endites represented by 1, 2, 2 and 3 setae, respectively. 



Maxilla (Fig. 2H) reduced, 2-segmented. Syncoxa with 

 single endite bearing unipinnate seta and conspicuous 

 aesthetasc-like structure representing modified seta with chi- 

 tinized dorsal margin and tubular membranous part ventrally; 

 exit of maxillary gland discernible in proximal half. Allobasis 

 drawn out into pinnate claw bearing serrate seta at its base. 

 No trace of endopod. 



Maxilliped (Fig. 4F) subchelate. Syncoxa and basis without 

 armature but with 3 spinular rows each. Endopod repre- 

 sented by strong claw bearing tiny spinules along distal half of 

 inner margin; an accessory setule is located at the base of the 

 claw. 



PI (Fig. 3A). Praecoxa a small sclerite located around the 

 outer lateral margin of the limb base. Intercoxal sclerite a 

 minute rounded plate. Coxa with spinular row. Basis with 

 inner and outer basal seta and with spinules at middle distal 

 margin. Exopod 2-segmented, proximal segment with blunt 

 spine bearing long setules, distal segment with 2 geniculate 

 setae and 1 unipinnate spine. Endopod 2-segmented, elon- 

 gate, prehensile; proximal segment about twice as long as 

 exopod, with serrate inner seta near proximal margin; distal 

 segment with 1 geniculate seta, 1 short claw and a patch of 



