Trichorhina Budde-Lund 1908

Key to the species of Trichorhina from Brazil

1. Ischiumof pereopod VIIof themalewithconspicuous expansion................... T. tatianae Ischium without expansion.................2

2. Eyeless or with only one diminute ommatidium; unpigmented........................... 3 At least one well developed ommatidium; colorvariable........................... 4

3. Telson acutely pointed; antennary tubercles prominent........................... T. brasiliensis Telson subtriangular broadly rounded; antennary tuberclesnotprominent............... T. pittieri

4. Pereonite VII with two noduli laterales on each side.............................. 5 Pereonite VII with only one nodulus lateralis oneachside......................... 7

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5. Left mandible with rods between molar and incisory processes; eye with five ommatidia; nodulilaterales withfeaturelessbase................................ T. guanophila Left mandible without rods between molar and incisory processes; eye with one or two ommatidia; nodulilaterales with base provided withtwolateralprocesses............. 6

6. Eye formed by two unequally sized.............................. T. heterophthalma Eyeformedbyonlyoneommatidium................................. T. tomentosa

7. Second article of antennal peduncle ridged or crested..............................8 Secondarticleof antennalpeduncle............................................9

8. Eye formed by 15 ommatidia; second article of antennal peduncle with dorsal keel (Fig. 111)................. T. tropidocerata sp. nov.

Eye formed by five ommatidia; second article of antennal peduncle with outer crenulate (Fig. 12)................... T. biumbonata sp. nov.

9. Eye formed by a single very large ommatidium.......................... T. macrops Eye formedbyatleastfour ommatidia.... 10

10. Eyeswithfourommatidia............ 11 Eyeswithfivetotenommatidia......... 13

11. Noduli laterales very close to the posterior border of pereonites I–VII (ratio b/c smaller than 0.1).......................12 Noduli laterales located more far of the posterior border of pereonites I–VII (ratio b/c larger than 0.2, larger than 0.1 in P VII) (Fig. 6)................... T. sexdens sp. nov.

12. Telsonclearlyacute............. T. acuta Telsonsubtriangular, withroundedapex.. T.paraensis

13. Eyesformedbyeight totenommatidia...... 14 Eyes formed by five to six ommatidia.......15

14. Nodulilaterales with steep increase from PIto PIIin d/c (Fig. 2)....... T. crassisetae sp. nov. Noduli laterales without steep increase from PIto PIIin d/c......... T. amazonica

15. Exite of maxillula with 4+4 (two cleft) teeth....................... T. argentina Exite of maxillula with 3+3–4 (zero to two cleft) teeth...........................16

16. Pereon yellow to brown, pleon unpigmented; only six teeth at exite of maxillula, none cleft; molar process of left mandible with three penicils.................... T. bicolor Body background of pereon and pleon uniform; seven teeth in exite of maxillula, one or two cleft; molar process of left mandible with onlyonepenicil.................... 17

17. Body background brown with darker spots in head; eyes lighter; one cleft tooth in exite of maxillula (Fig. 50)............... T. lenkoi sp. nov. Body pale yellow to unpigmented; eyes dark brown to black; two cleft teeth in exite of maxillula...............................18

18. Carpus of pereopod Iof male without bristle field (Fig. 70).......... T. myrmecophila sp. nov. Carpus of pereopod Iof male with bristle field (Fig. 90)............. T. orensis sp. nov.