Typhlamphiascus Lang 1944

Key to the species of Typhlamphiascus Lang, 1944

1. P4 ENP3 with two inner setae (five setae in all). Female: P5 EXP with tip normal or hook-like. Male: P1 basis with inner seta normal or modified, elongate.........2 [Por’s group I (Pors 1963)]

– P4 ENP3 with one inner seta (four setae in all). Female: P5 EXP with tip normal. Male: P1 basis with inner seta normal, not modified....................................11 [Por’s group II (Pors 1963)]

2. Female P5 EXP with tip hook-like; endopodal lobe with apical outer seta very small............3

– Female P5 EXP with tip normal......................................................................................................4

3. Female: antennule seven-segmented; P5 EXP and endopodal lobe with five setae each, endopodal lobe with apical inner element spiniform; P4 EXP3 with three inner setae (male unknown) .............................................................. T. dentipes (I.C. Thompson & A. Scott, 1903)

– Female: antennule eight-segmented; P5 EXP and endopodal lobe with five setae each, endopodal lobe with apical inner element setiform; P4 EXP3 with two inner setae (male unknown) .................................................................. T. blanchardi (T. Scott & A. Scott, 1895) 1

4. Female: antennule eight-segmented; P5 EXP with five, endopodal lobe with four setae. Male: P1 basis with inner spine not modified, with three to five inner accessory spines; P5 EXP with four, endopodal lobe with two bifurcate setae ..... T. gracilicaudatus (I.C. Thompson & A. Scott, 1903) 6

– These characters not combined........................................................................................................5

5. Female: antennule eight-segmented; P5 EXP with four, endopodal lobe with five setae. Male: P1 basis with inner element modified, elongate; P5 EXP with four, endopodal lobe with two bifurcate setae .................................................................................... T. longifurcatus Rouch, 1962

– These characters not combined.......................................................................................................6

6. Female: P5 EXP and endopodal lobe with five setae each............................................................7

– Female: P5 EXP with six setae, endopodal lobe with five setae.....................................................8

7. Female: caudal rami 1.4–1.5 times as long as wide, shorter than anal somite; P5 second exopodal seta from outer to inner margin 1.5 times as long as third element; third seta 1.7 times as long as first seta and longer than exopod; innermost (fifth) seta 1.2 times as long as fourth seta. Male: P1 basis with inner spine normal, with seven to eight inner accessory spines; P5 EXP with five seate, endopodal lobe with two setae; P5 second exopodal seta from outer to inner margin shorter than first seta ....................................................................................... T. gracilis Por, 1963 7

– Female: caudal rami twice as long as wide, as long as anal somite; P5 second exopodal seta from outer to inner margin 4.5 times as long as third element; third seta as long as first seta and shorter than exopod; innermost (fifth) seta 2.3 times as long as fourth seta. Male: P1 basis with inner spine modified, elongate, with three inner accessory spines; P5 EXP with five setae, endopodal lobe with two setae; P5 second exopodal seta from outer to inner margin longer than first seta .... .......................................................................................................................... T. drachi Soyer, 1963

8. P4 EXP3 without inner armature, formula 0,2,3. Female: antennule nine-segmented (male unknown) ............................................................................................... T. accraensis (T. Scott, 1894)

– P4 EXP3 with two inner setae, formula 2,2,3. Female: antennule eight-segmented............9

9. Caudal rami 1.2 times as long as wide, shorter than anal somite ... T. capensis Kunz, 1975 comb. nov.

– Caudal rami twice as long as wide, as long as anal somite.........................................................10

10. Caudal rami as long as anal somite, rather cylindrical, with inner margin slightly concave. Female: second antennulary segment about 1.5 times as wide as long; P5 EXP with three outer setae subequal in length; outermost seta of P5 endopodal lobe long,reaching well beyond tip of exopod. Male: P1basis with three inner accessory spines, inner seta normal, not modified; P5 EXP with six setae, endopodal lobe with two bifurcate setae; P5 innermost exopodal seta bifurcate ......... T. lutincola Soyer, 1963

– Caudal rami 1.5 times as long as anal somite, elongate, elliptic. Female: second antennulary segment three times as long as wide; P5 EXP with outer proximal seta very long, medial and subdistal outer setae small and subequal in length. Male: second antennulary segment three times as long as wide; P1 basis without inner accessory spines, inner seta modified, elongate; P5 EXP with four setae, endopodal lobe with two bifurcate setae; P5 innermost exopodal seta normal ... T. bouligandi Soyer, 1971

11. P3 ENP3 with one inner seta, formula 1,2,1..............................................................................12

– P3 ENP3 with two inner setae, formula 2,2,1..............................................................................13

12. P2–P3 EXP3 without inner armature, formula 0,2,3; caudal rami nearly twice as long as wide (length: width ratio 1.8). Male: P1 basis with three inner accessory spines; P5 EXP with six normal (not bifurcated) setae, endopodal lobe with two bifurcate setae ...... T. higginsi Chullasorn, 2009

– P2–P3 EXP3 with one inner seta, formula 1,2,3; caudal rami slightly more than two times as long as broad (length: width ratio 2.3) (male unknown) ..................... T. unisetosus Lang, 1965

13. Caudal rami slightly more than three times as long as wide (length: width ratio 3.2). Female: P5 EXP with six setae, endopodal lobe with four setae. Male: P1 basis with eight inner accessory spines; P5 EXP with four normal setae, endopodal lobe with two bifurcated elements ............... .................................................................................................................. T. tuerkayi Ma & Li, 2017

– Female: P5 EXP with six, endopodal lobe with five setae...........................................................14

14. P4 ENP2 without inner seta; caudal rami from 1.7 to 2.2 times as long as wide. Male: P1 basis with four 3 or from seven to eight 4 inner accessory spines; P5 EXP with six normal setae, endopodal lobe with two bifurcated elements ........................ T. typhlops (Sars, 1906) 2,8

– P4 ENP2 with inner seta...............................................................................................................15

15. P1 EXP3 with four elements; caudal rami three times as long as wide (male unknown) ........... ............................................................................ T. brevicornis (I.C. Thompson & A. Scott, 1903)

– P1 EXP3 with five elements..........................................................................................................16

16. Caudal rami less than 1.5 times as long as wide.....................................................................17

– Caudal rami more than 1.5 times as long as wide...................................................................18

17. Caudal rami about as long as wide. Female: P5 EXP elongate. Male: P1 basis with three inner accessory spines; P5 EXP with five setae ..................................... T. latifurca Por, 1968

– Caudal rami length: width ratio from 1.3 to 1.5. Female: P5 EXP oval. Male: P1 basis with eight inner accessory spines; P5 EXP with six setae .......................... T. ovale Wells & Rao, 1987

18. Caudal seta V characteristically deformed proximally, with inner blunt outgrowth ...................... .................................................................................................................... T. typhloides (Sars, 1911)

– Caudal seta V normal.....................................................................................................................19

19. Length: width ratio of caudal rami variable, from about 1.7 to 3.1 times as long as wide, with concave inner margins, with lenticular, biconvex thickening of external chitinous walls, with one spinule on inner distal margin. Female: ventral surface of posterior half of genital double-somite without medial spinules, with two posterior transverse sets of three to five spinules, each close to outer margin; ventral surface of fourth urosomite with one medial spinular row of 21 to 30 spinules and one posterior transverse row of 15 to 24 spinules; ventral surface of fifth urosomite with two medial sets of three to ten spinules on each side or with a medial continuous row of about 24 spinules, and with short posterior row of four to six medial spinules or with three sets of spinules of which medial one with ten spinules and marginal sets with three to four spinules; ventral surface of anal somite without spinular ornamentation. Male: ventral surface of third urosomite with two medial transverse sets of four spinules each or with medial continuous spinular row of eight to ten transverse spinules, posterior margin with transverse row of 14 to 26 spinules; ventral surface of fourth urosomite with two medial sets of four to eight transverse spinules or with short medial row of four transverse spinules, and with posterior transverse row of 16 to 24 spinules; ventral surface of fifth urosomite without medial spinules or with two medial sets of four transverse spinules, posterior margin with transverse row of four to 12 spinules; P1 basis with three to five inner accessory spines; P5 EXP with six setae, endopodal lobe with two bifurcate setae ............................. ............................................................................................... T. confusus confusus (T. Scott, 1902) 5,7

– Caudal rami from about 1.7 to 3.2 times as long as wide; ventral spinular pattern of female and male and number of inner accessory spines on male P1 basis different..........................20

20. Caudal rami shorter than anal somite...........................................................................................21

– Caudal rami longer than anal somite...........................................................................................22

21. Rostrum with concave lateral margin proximally; length: width ratio of caudal rami 1.7. Female: P5 EXP with three outer setae subequal in length, fourth seta from outer to inner margin longer than preceding elements and of about same length as innermost seta. Male: P1 basis with four inner accessory spines ......... T. confusus erythraeicus Por, 1963

– Rostrum with convex lateral margin proximally; length: width ratio of caudal rami 1.7. Female: P5 EXP with outer proximal seta shorter than two neighbouring elements, fourth seta from outer to inner margin shorter than two preceding elements and shorter than innermost seta. Male: P1 basis with two inner accessory spines ....................... T. lamellifer (Sars, 1911) 8

22. Length: width ratio of caudal rami from 2.0 to 3.2. Female: three outer setae and innermost seta of P5 EXP long, subequal in length. Male: P1 basis with five to seven inner accessory spines ................................................... T. confusus gullmaricus Por, 1963

– Length: width of caudal rami from 1.7 to 2.2. Female: proximal seta of P5 EXP longer than two following elements, all three outer setae noticeably shorter than innermost element. Male: P1 basis with three inner accessory spines; innermost seta of P5 EXP bifurcate.........23

23. Caudal rami with subdistal inner set of long spinules forming a comb. Female: both halves of genital double-somite without dorsolateral spinular ornamentation; setae of P6 subequal in length; with five midventral spinules on fourth urosomite. Male: genital, third and fourth urosomites without dorsolateral spinular ornamentation ............................ T. pectinifer Lang, 1965

– Caudal rami with few subdistal inner short spinules; inner setae of P6 noticeably longer than outer ones. Female: both halves of genital double-somite with a few posterior spinules dorsolaterally; with 13 midventral spinules on fourth urosomite. Male: genital, third and fourth urosomites with few a dorsolateral spinules ......................................... T. medici sp. nov.