Willemia, Borner, 1901

García-Gómez, Arturo & Palacios-Vargas, José G., 2019, Description of a new species of Willemia (Collembola: Hypogastruridae) from Panama with key to Willemia species occurring in the Americas, Zootaxa 4674 (5), pp. 564-570 : 568-569

Identification key to species of the genus Willemia in the Americas

1 Seta a0 present on the head............................................................................. 2

–– Seta a0 absent on the head............................................................................. 18

2 Anal spines present (usually 2, sometimes 1)............................................................... 3

–– Anal spines absent................................................................................... 14

3 Seta m3’ present on the abdominal tergum V........................... W. bellingeri Palacios-Vargas & Vázquez, 1998

–– Seta m3’ absent on the abdominal tergum V................................................................ 4

4 Setae a1 on abdominal sternum IV present................................................................. 5

–– Setae a1 on abdominal sternum IV absent................................................................. 11

5 Abdominal tergum V with seta p2 absent................................................................... 6

–– Abdominal tergum V with seta p2 present.................................................................. 7

6 Postantennal organ with 10 to 11 vesicles; tibiotarsi I with 10–11 setae… W. psammophila Palacios-Vargas & Thibaud, 2001

–– Postantennal organ with 8 vesicles; tibiotarsi I with 15 setae........ W. iztaccihuatlensis García-Gómez & Cutz-Pool, 2008

7 Setae m1 present on abdominal tergum IV................................................................. 8

–– Setae m1 absent on abdominal tergum IV................................................................. 10

8 Setae m3 present on abdominal terga II and III; 2 hr setae on anal lobes................... W. anophthalma Börner, 1901

–– Setae m3 absent on abdominal terga II and III; 3 hr setae on anal lobes........................................... 9

9 S-seta i1 (S9) present on antennal segment IV; 2 prelabral setae................................ W. similis Mills, 1934

–– S-seta i1 absent (it is not differentiated from ordinary setae) on antennal segment IV; 4 prelabral setae.............................................................................................. W. chistianseni D´Haese, 1998

10 S-setae e2 (S1) and i (S2) present on antennal segment IV...................... W. dubia Christiansen & Bellinger, 1980

–– S-setae e2 and i absent (e2 and I not differentiated from ordinary setae) on antennal segment IV..................................................................................................... W. scandinavica Stach, 1949

11 Postantennal organ with 4 or 5 vesicles................................................ W. intermedia Mills, 1934

–– Postantennal organ with 7 vesicles or more................................................................ 12

12 S– –setae e3 (S4) and i2 (S7) on antennal segment IV not globular; tibiotarsi I, II, and III with 14, 14, and 13 setae, respectively........................................................................... W. persimilis Bonet, 1945

–– S-setae e3 and i2 on antennal segment IV globular.......................................................... 13

13 Setae a2 absent on abdominal terga II and III; setae m1 and m3 absent on abdominal tergum IV..... W. bulbosa Bonet, 1945

–– Setae a2 present on abdominal terga II and III; setae m1 and m3 present on abdominal tergum IV................................................................................................... W. subbulbosa Thibaud, 1994

14 S-setae on antennal segment IV all thick and subcylindrical................................................... 15

–– S-setae on antennal segment IV not thick and subcylindrical.................................................. 16

15 Postantennal organ vesicles with numerous secondary tubercles.......................... W. granulata Fjellberg, 1985

–– Postantennal organ vesicles smooth..................................................... W. acantha Bonet, 1945

16 Setae a2 absent on abdominal terga II and III; s-seta e2 (S1) present on antennal segment IV and some s-setae candle flameshaped.............................................................................. W. denisi Mills, 1934

–– Setae a2 present on abdominal terga II and III; s-setae e2 and I (S2) absent on antennal segment IV (i.e., S1 and S2 not differentiated from ordinary setae)........................................................................... 17

17 Postantennal organ vesicles with numerous secondary tubercles.............................. W. arida Fjellberg, 1991

–– Postantennal organ vesicles simple.................................................. W. fjellbergi Potapov, 1994

18 S-setae e3 (S4) and i2 (S7) of antennal segment IV both small, not placed in cavity, and not covered by tegumental fold... 19

–– S-setae e3 and i2 of antennal segment IV both large, globular, placed in cavity, and covered in part by tegumental fold—bud-denbrocki-group..................................................................................... 21

19 Anal spines present............................................... W. arenicola Palacios-Vargas & Vázquez, 1988

–– Anal spines absent................................................................................... 20

20 Postantennal organ with 15 vesicles or more................................... W. meybholae Palacios-Vargas, 1987

–– Postantennal organ with 4 to 5 vesicles..................................... W. zeppelini D´Haese & Thibaud, 2011

21 Tibiotarsi I and II with 11 setae; tibiotarsi III with 10 or 11 setae........................ W. buddenbrocki Hüther, 1959

–– All tibiotarsi with 12 setae............................................................................. 22

22 Antennal segment IV with two subcylindrical s-setae.................................... W. brevispina Hüther, 1962

–– Antennal segment IV with four subcylindrical s-setae....................................... W. panamaensis sp. nov.