PUERTO RICAN COPEPODS — GONZALEZ AND BOWMAN 259 



Family Tortanidae 



With the characters of the only genus, Tortanus. 



Genus Tortanus Giesbrecht 



Head without lateral hooks. Eye large, without lenses. Rostrum 

 absent. Horsehoe-shaped plated fringe with hairs anterior to upper 

 hp. Head and PedSeg 1 separated. PedSeg 5 fused with or separate 

 from PedSeg 4, pointed and sometimes asymmetrical in female, 

 rounded in male, Urosome 2-3-segmented and usually asymmetrical 

 iu female, 5-segmented in male. Caudal rami usually very asymmet- 

 rical in female, less so in male. Al 17-segmented, male right Al pre- 

 hensile, thickened in middle. Ri of A2 a little longer than Re. B2 

 of Md palp long; outermost tooth of gnathal lobe large and well sep- 

 arated from other teeth. Mxl reduced to basal segment bearing short 

 broad proximal lobe and long narrow distal lobe, the latter with 2 

 long and 1 shorter apical setae. Mx2 with much reduced proximal 

 lobes. Mxp with well-developed basal segment armed with strong 

 setae; endopod much reduced. Re of P1-P4 3-segmented; Ri of Pi 2- 

 or 3-segmented, of P2-P4 2-segmented. P5 uniramous in both sexes; 

 2-3-segmented and sometimes asymmetrical in female; right P5 of 

 male forming a chela. 



Tortanus cotnpernis, new species 



Figures llg, 12b-i, 13a-j 



Very similar to T. setacaudatus Williams but differing as follows : 

 Female. — Length 1.14-1.19 mm. Prosome more slender, length: 

 width = about 2.7 (about 2.3 in T. setacaudatus). Urosome more 

 slender; anal spine smaller. Caudal rami not so straight; lateral 

 margins concave; bent inward and in contact or nearly so near base; 

 more slender, length: width = 5.4 (left ramus) and 4.6 (right 

 ramus) (3.6 in both rami in T. setacaudatus). Distal segment of P5 

 with inner tooth widely separated from 2 outer teeth; inner margin 

 with 3 setae near distal end. 



Male. — Length 1.02-1.08 mm. Length : width of prosome = 

 2.8-3.0 (2.4 in T. setacaudatus). Urosome segment 2 with lobe on 

 posterior part of right margin larger, of different shape (cf. figs. 12A, 

 12Z), bearing 2 short hairs on posterior margin. Caudal rami as in 

 female, bent inward near proximal end; right ramus slightly longer 

 than left. Al as in T. setacaudatus, but segments slightly narrower. 

 Segment 2 of P5 armed at tip with curved process, long heavy seta, 

 and slender seta arising at base of heavy seta and crossing base of 

 curved process. 



