62 



R. HUYS AND W. LEE 



Table 1. Diagnostic characters of Esola species 



[species A = Esola spec, sensu Mielke (1997)]. 



CR = caudal rami, SD = sexual dimorphism. 







longicauda 



bulbifera 



galapagoensis 



canalis 



profunda 



vervoorti 



lobata 



species A 



9 size (urn) 



? 



643-714 



330-460 



585-658 



500-529 



510 



490-530 



470 



cJ size (|im) 



550 



500-524 



300-360 



? 



7 



389-415 



380-450 



7 



cephalothorax dorsal spinule row 



? 



present 



? 



present 



present 



absent 



7 



7 



mandible - endopod 



? 



fused, 3 setae 



fused, 2 setae 



free, 3 setae 



free, 3 setae 



free, 3 setae 



free, 3 setae 



free, 2 setae? 



- exopod 



? 



absent 



absent 



1 seta 



absent 



absent 



absent 



absent 



- basis 



? 



2 setae 



2 setae 



1 seta 



2 setae 



1 seta 



2 setae 



2 setae? 



PI exp-2 setal number 



4 



5 



4 



5 



5 



5 



5 



4 



PI exp-2 outer apical seta SD 



7 



- 



- 



7 



7 



+ 



- 



7 



ratio PI enp-1 : enp-2 claw 



0.83 



0.50 



0.37 



0.50 



0.55 



0.55 



0.55 



7 



P2-P3 enp- 1 inner seta 



present 



present 



present 



present 



present 



absent 



present 



present 



P3 enp-2 apophysis S 



? 



smooth 



smooth 



7 



7 



dentate 



smooth 



7 



P4 enp-1 inner seta 



normal 



vestigial 



absent 



vestigial 



absent 



absent 



absent 



vestigial 



P5 benp 9 outer apical seta 



plumose 



plumose 



naked 



plumose 



plumose 



plumose 



plumose 



7 



- length* 



short 



long 



vestigial 



very short 



short 



short 



-short 



7 



CR - pore position 



ventral 



medioventral 



ventral 



mediodorsal 



ventral 



medial 



ventral 



7 



- 9 medial swelling 



weak 



strong 



strong 



moderate 



moderate 



moderate 



slight 



moderate 



- 2 length : distal width 



3.0 



2.3 



3.4 



3.0 



2.5 



2.1 



3.8 



7 



- 6 length : distal width 



7 



2.5 



3.4 



7 



7 



1.7 



3.2 



? 





*: very short = not extending to insertion level of middle outer exopodal seta; short = extending to about insertion level of middle outer exopodal seta; long = extending to 

 about apex of exopod [Note that in E. lobata sp. nov. the endopodal lobe is secondarily elongated so that its outer apical seta extends beyond the insertion level of the middle 

 outer exopodal seta despite being short]. 



Caudal rami (Fig. 6A-C) widely separated; gradually tapering 

 posteriorly and about as long as anal somite; proximal half expanded 

 with major swelling medially and dorsally, and to a lesser extent 

 ventrally (Fig. 6A); large cup-shaped pore located mediodorsally 

 (Fig. 6A) leading to small tube-pore. Armature as in E. bulbifera. 



Antennule (Fig. 6D) slender, 6-segmented, with 1 large (proxi- 

 mal) and 2 small spinous processes along posterior margin of 

 segment 1 . Segment 1 with long spinules around anterior margin. 

 Segments 2 and 3 equally long. Armature formula: 1-[1 pinnate], 2- 

 [7 + 1 pinnate], 3-[6],4-[(2 + ae)],5-[l],6-[9 + acrothek], Aesthetasc 

 on segment 4 fused basally to 2 setae. Acrothek consisting of 

 aesthetasc and 2 naked setae; set on apical pedestal. 



Antennary exopod (Fig. 6F) elongate exopod bearing 2 lateral and 

 2 apical pinnate elements, and a longitudinal row of coarse spinules 

 proximally. 



Labrum with ornamentation as in E. bulbifera. 



Mandible (Fig. 6E) with small 2-segmented palp; proximal seg- 

 ment with 1 inner (basal) seta and 1 small outer seta representing 

 exopod; endopod a free segment with 3 setae. 



Maxilliped (Fig.7F). Basis more slender than in E. bulbifera and 

 spinules along outer margin coarser. 



PI (Fig. 7 A) similar to that of E. bulbifera but basis forming 

 shorter pedestal for endopod, and both exopod (but exp-1 extending 

 to distal margin of basal pedestal) and enp-2 somewhat shorter; exp- 

 2 with 3 outer setae and 2 geniculate setae apically. 



P2-P4 (Fig. 7B-D). P2-P3 enp- 1 with multipinnate inner seta; P4 

 enp-1 with vestigial inner seta. Outer spine of P2-P4 enp-2 shorter 

 than in E. bulbifera. Armature formula as follows: 



Exopod 



Endopod 



0.1.123 



1.221 



0.1.223 



1.321 



0.1.223 



1.221 



[ 6: probably 1.1.220] 



P5 (Fig. 7E). Endopodal lobe small, not extending beyond inser- 

 tion sites of proximal outer setae of exopod; with 2 apical and 2 

 widely separated inner setae; outer apical seta very short. Exopod 

 more slender than in E. bulbifera; with 1 apical, 1 inner and 4 outer 

 setae; length of inner (ratio to exopod length 1.15 vs 1.5 in 



E. bulbifera) and apical seta (ratio to exopod length 1.25 vs 2.2 in E. 

 bulbifera) distinctly shorter. 



MALE. Unknown. 



Remarks. Gurney (1927) collected this species from the plankton 

 at Port Tauftq and Le Cap, and in sediment samples from El Ferdane. 

 He attributed his material to L. bulbifera but remarked on some 

 differences with Norman's (191 1) holotype, such as the discrepancy 

 in body size (0.68 mm instead of 0.80 mm), the PI endopod which is 

 more slender in the Scottish specimen and the presence of an 

 additional seta (the innermost) on the P5 baseoendopod. We have 

 found these differences to be of no value in discriminating both 

 species. Norman (1911) clearly overlooked the innermost seta (as 

 indicated by the gap along the medial margin in his figure of the 

 baseoendopod). Also, based on a larger sample of E. bulbifera we 

 found this species on average to be significantly smaller than Nor- 

 man's observed size of 0.8 mm, approximating the mean length off. 

 canalis (681 urn vs 621 urn; see also Table I). There is no significant 

 difference in the PI endopod of both species although the proximal 

 segment appears to be longer in E. canalis and the distal segment to be 

 longer in E. bulbifera. Gurney (1927) illustrated the P5, caudal rami 

 and the female habitus in lateral view. His illustration of the caudal 

 rami gives a slightly distorted view in that the rami appear to be much 

 longer than in reality. Por & Marcus (1972) recorded E. longicauda 

 from four localities in the Suez Canal ; it is likely that these records and 

 Por's (1967) previous record from the Gulf of Elat refer to E. canalis. 

 E. canalis is most closely related to E. bulbifera. Females of the 

 former can be differentiated by the conical caudal rami, the medi- 

 odorsal position of the cup-shaped pores on these rami, and the P5 

 endopodal lobe which is significantly shorter and has a much 

 smaller outer apical seta. Additional differences can be found in the 

 proportional lengths of the proximal antennulary segments, the 

 slenderness of the maxilliped and the size of particular setae on the 

 P2-P4 endopods and P5 exopod. E. canalis is the only species of the 

 genus which has retained a vestige of the mandibular exopod. 



Esola lobata sp. nov. 



Esola longicauda (Edwards, 1891) sensu Mielke (1997) 



Type LOCALITY. Bunaken Island near Manado, North Sulawesi 

 (Indonesia); sublittoral sand between seagrass and corals. 



