http://www.collembola.org/key/willemia.htm - Last updated on 2017.10.31 by Frans Janssens
Checklist of the Collembola: Key to the species of Willemia

This key is still under construction. Note that missing figures will be provided as soon as possible. Currently, the key is in the feasibility study phase to find out how to integrate in the checklist in a modular way a key that has been generated with DELTA.

Cyrille D'Haese, Laboratoire d'Entomologie, Muséum national d'Histoire naturelle, F-75005 Paris, France
Arturo García-Gómez, Laboratorio de Ecología y Sistemática de Microartrópodos, Universidad NAM, México D.F.
Leopoldo Q. Cutz-Pool, Laboratorio de Ecología y Sistemática de Microartrópodos, Universidad NAM, México D.F.
Frans Janssens, Department of Biology, University of Antwerp, Antwerp, B-2020, Belgium

Rationale

The rationale for taxa used and not used as well as subtaxonomic classification for some taxa is to be provided.

Key

Note that no distinction between subtaxa and taxa is made in the key.

1(0).   Setae a0 absent on the head................................. 2
        Setae a0 present on the head............................... 13
 
2(1).   Sensilla e3 and i2 of antennal segment iv are large, globular,
          placed in cavity and covered in part by tegumental fold;
          setae m3 absent on third thoracic tergum.................. 3
        Sensilla e3 and i2 of antennal segment iv are small, globular,
          not placed in cavity and not covered by tegumental fold;
          setae m3 present on third thoracic tergum................ 12
 
3(2).   Fifth abdominal tergum with setae s in p2 position; first
          thoracic tergum with 3 + 3 setae.......................... 4
        Fifth abdominal tergum with setae s in p3 position; first
          thoracic tergum with 2 + 2 setae, curved and crenellated....
           ............................................... nadchatrami
 
4(3).   Apical vesicle absent; anal spines absent................... 5
        Apical vesicle present; anal spines present................. 6
 
5(4).   Antennal segment iv with ordinary setae and two lanceolate
          setae; postantennal organ with 15 to 17 vesicles. deharvengi
        Antennal segment iv with ordinary setae, without lanceolate
          setae; postantennal organ with 18 to 20 vesicles. setonychia
 
6(4).   Abdominal terga iv and v with setae s lanceolate.... delamarei
        Abdominal terga iv and v with setae s subcylindrical and
          acuminate................................................. 7
 
7(6).   Tibiotarsi i and ii with 11 setae, tibiotarsi iii with 11 or
          10 setae.................................................. 8
        Tibiotarsi with 12 setae................................... 10
 
8(7).   Postantennal organ with 12 to 14 vesicles; setae c1 absent on
          the head.................................................. 9
        Postantennal organ with about 20 vesicles; setae c1 present on
          the head.......................................... annapurna
 
9(8).   Setae a3 absent on abdominal sterna ii and iv; setae s m7 on
          third thoracic tergum lanceolate..................... wandae
        Setae a3 present on abdominal sterna ii and iv; setae s m7 on
          third thoracic tergum subcylindrical........... buddenbrocki
 
10(7).  Antennal segment iv with four subcylindrical sensilla hardly
          distinguishable from ordinary setae; third thoracic tergum
          with setae s m7 lanceolate....................... nepalensis
        Antennal segment iv with two or four subcylindrical sensilla
          clearly differentiated from ordinary setae; third thoracic
          tergum with setae s m7 subcylindrical and acuminate...... 11
 
11(10). Antennal segment iv with four subcylindrical sensilla;
          postantennal organ with 10 to 15 vesicles..... neocaledonica
        Antennal segment iv with two subcylindrical sensilla;
          postantennal organ with 7 to 10 vesicles......... brevispina
 
12(2).  Postantennal organ with 10 to 150 vesicles; anal spines
          present........................................... arenicola
        Postantennal organ with 15 vesicles or more; anal spines
          absent............................................ meybholae
 
13(1).  Setae a1 absent on fourth abdominal sternum................ 14
        Setae a1 present on fourth abdominal sternum............... 27
 
14(13). Tibiotarsi with 11 or 12 setae; ventral tube with 5 + 5 setae.
           ........................................................ 15
        Tibiotarsi with more than 12 setae; ventral tube with 4 + 40
          setae.................................................... 16
 
15(14). Postantennal organ with 3 vesicles; tibiotarsi iii with 110
          setae............................................. trilobata
        Postantennal organ with 4 vesicles; tibiotarsi iii with 120
          setae.............................................. namibiae
 
16(14). Anal spines absent......................................... 17
        Anal spines present........................................ 23
 
17(16). Sensilla on antennal segment iv, all thick and subcylindrical.
           ................................................. granulata
        Sensilla on antennal segment iv, with another shape........ 18
 
18(17). Sensilla i1 and d absent on antennal segment iv - i. e. d and
          i1 not differentiated from ordinary setae; setae a2 present
          on abdominal terga ii and iii............................ 19
        Sensilla i1 present on antennal segment iv and some sensilla
          are candle flame-shaped; setae a2 absent on abdominal terga
          ii and iii............................................... 22
 
19(18). Antennal segment iv with 2 sensilla - e3 and i2 - globular. 20
        Antennal segment iv with 3 sensilla - e2, e3 and i2 candle
          flame-shaped.................................... trisphaerae
 
20(19). Postantennal organ's vesicles smooth....................... 21
        Postantennal organ's vesicles with numerous secondary
          tubercles............................................. arida
 
21(20). Setae m2 absent on fourth abdominal tergum; setae s
          subcylindrical with acuminate apex on first abdominal
          tergum............................................. japonica
        Setae m2 present on fourth abdominal tergum; setae s
          lanceolate on first abdominal tergum............. fjellbergi
 
22(18). Sensilla d absent on antennal segment iv - i. e. d not
          differentiated from ordinary setae............ elisabetharum
        Sensilla d present on antennal segment iv.............. denisi
 
23(16). Fifth abdominal tergum with setae s in p2 position - thus
          setae p2 absent.......................................... 24
        Fifth abdominal tergum with setae s in p3 position - thus
          setae p2 present......................................... 26
 
24(23). Postantennal organ with 4 vesicles................. intermedia
        Postantennal organ with 7 vesicles or more................. 25
 
25(24). First, second and third tibiotarsus with 12, 12 and 11 setae
          respectively; setae a2 present on abdominal terga ii and
          iii; setae m1 and m3 present on fourth abdominal tergum.....
           ................................................ subbulbosa
        First, second and third tibiotarsus with 14, 14 and 13 setae
          respectively; setae a2 absent on abdominal terga ii and iii;
          setae m1 and m3 absent on fourth abdominal tergum...........
           ................................................ persimilis
 
26(23). Apical vesicle simple; postantennal organ's vesicles
          blackberry-shaped; postantennal organ with 4 vesicles.......
           ............................................... multilobata
        Apical vesicle trilobate; postantennal organ's vesicles
          smooth; postantennal organ with 6 to 80 vesicles. bellingeri
 
27(13). Fifth abdominal tergum with setae s in p2 position - thus
          setae p2 absent.......................................... 28
        Fifth abdominal tergum with setae s in p3 position - thus
          setae p2 present......................................... 30
 
28(27). M-row absent on fourth abdominal tergum; setae a4 absent on
          second and third thoracic tergum...................... virae
        M-row present on fourth abdominal tergum; setae a4 present on
          second and third thoracic tergum......................... 29
 
29(28). Postantennal organ with 7 vesicles; sensillum e1 present on
          fourth antennal segment; setae m4 present on fourth
          abdominal tergum.................................... bedosae
        Postantennal organ with 8 vesicles; sensillum e1 absent on
          fourth antennal segment; setae m4 absent on fourth abdominal
          tergum.................................... iztaccihuatlensis
 
30(27). Setae m1 absent on fourth abdominal tergum................. 31
        Setae m1 present on fourth abdominal tergum................ 33
 
31(30). Sensilla d and i1 absent - i. e. d and i1 not differentiated
          from ordinary setae - on antennal segment iv............. 32
        Sensilla d and i1 present on antennal segment iv........ dubia
 
32(31). Empodial appendage absent............................. koreana
        Empodial appendage present....................... scandinavica
 
33(30). Anal lobes with 2 hr setae; setae m3 present on abdominal
          terga ii and iii................................ anophthalma
        Anal lobes with 3 hr setae; setae m3 absent on abdominal terga
          ii and iii............................................... 34
 
34(33). Number of prelabral setae 2; sensilla e1 present on antennal
          segment iv.......................................... similis
        Number of prelabral setae 4; sensilla e1 absent - i. e. e1 not
          differentiated from ordinary setae - on antennal segment iv.
           ............................................. christianseni

Endnotes

1 Willemia biseta Christiansen & Bellinger, 1980 and Willemia bulbosa Bonet, 1945 are not included in the key.


Differential diagnoses

annapurna
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with about 20 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae c1 present on the head. Setae m3 absent on third thoracic tergum. Tibiotarsi i and ii with 11 setae, tibiotarsi iii with 11 or 10 setae.

anophthalma
Anal lobes with 2 hr setae. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 present on fourth abdominal tergum. Setae m3 present on abdominal terga ii and iii.

arenicola
Anal spines present. Postantennal organ with 10 to 150 vesicles. Sensilla e3 and i2 of antennal segment iv are small, globular, not placed in cavity and not covered by tegumental fold. Setae a0 absent on the head. Setae m3 present on third thoracic tergum.

arida
Anal spines absent. Antennal segment iv with 2 sensilla - e3 and i2 - globular. Postantennal organ’s vesicles with numerous secondary tubercles. Sensilla i1 and d absent on antennal segment iv - i. e. d and i1 not differentiated from ordinary setae. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 present on abdominal terga ii and iii. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

bedosae
Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. M-row present on fourth abdominal tergum. Postantennal organ with 7 vesicles. Sensillum e1 present on fourth antennal segment. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae a4 present on second and third thoracic tergum. Setae m4 present on fourth abdominal tergum.

bellingeri
Anal spines present. Apical vesicle trilobate. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Postantennal organ’s vesicles smooth. Postantennal organ with 6 to 80 vesicles. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

brevispina
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Antennal segment iv with two or four subcylindrical sensilla clearly differentiated from ordinary setae. Antennal segment iv with two subcylindrical sensilla. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 7 to 10 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum. Third thoracic tergum with setae s m7 subcylindrical and acuminate. Tibiotarsi with 12 setae.

buddenbrocki
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 12 to 14 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae a3 present on abdominal sterna ii and iv. Setae c1 absent on the head. Setae m3 absent on third thoracic tergum. Setae s m7 on third thoracic tergum subcylindrical. Tibiotarsi i and ii with 11 setae, tibiotarsi iii with 11 or 10 setae.

christianseni
Anal lobes with 3 hr setae. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Number of prelabral setae 4. Sensilla e1 absent - i. e. e1 not differentiated from ordinary setae - on antennal segment iv. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 present on fourth abdominal tergum. Setae m3 absent on abdominal terga ii and iii.

deharvengi
Anal spines absent. Antennal segment iv with ordinary setae and two lanceolate setae. Apical vesicle absent. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 15 to 17 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum.

delamarei
Abdominal terga iv and v with setae s lanceolate. Anal spines present. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum.

denisi
Anal spines absent. Sensilla d present on antennal segment iv. Sensilla i1 present on antennal segment iv and some sensilla are candle flame-shaped. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 absent on abdominal terga ii and iii. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

dubia
Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Sensilla d and i1 present on antennal segment iv. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 absent on fourth abdominal tergum.

elisabetharum
Anal spines absent. Sensilla d absent on antennal segment iv - i. e. d not differentiated from ordinary setae. Sensilla i1 present on antennal segment iv and some sensilla are candle flame-shaped. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 absent on abdominal terga ii and iii. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

fjellbergi
Anal spines absent. Antennal segment iv with 2 sensilla - e3 and i2 - globular. Postantennal organ’s vesicles smooth. Sensilla i1 and d absent on antennal segment iv - i. e. d and i1 not differentiated from ordinary setae. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 present on abdominal terga ii and iii. Setae m2 present on fourth abdominal tergum. Setae s lanceolate on first abdominal tergum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

granulata
Anal spines absent. Sensilla on antennal segment iv, all thick and subcylindrical. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

intermedia
Anal spines present. Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. Postantennal organ with 4 vesicles. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

iztaccihuatlensis
Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. M-row present on fourth abdominal tergum. Postantennal organ with 8 vesicles. Sensillum e1 absent on fourth antennal segment. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae a4 present on second and third thoracic tergum. Setae m4 absent on fourth abdominal tergum.

japonica
Anal spines absent. Antennal segment iv with 2 sensilla - e3 and i2 - globular. Postantennal organ’s vesicles smooth. Sensilla i1 and d absent on antennal segment iv - i. e. d and i1 not differentiated from ordinary setae. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 present on abdominal terga ii and iii. Setae m2 absent on fourth abdominal tergum. Setae s subcylindrical with acuminate apex on first abdominal tergum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

koreana
Empodial appendage absent. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Sensilla d and i1 absent - i. e. d and i1 not differentiated from ordinary setae - on antennal segment iv. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 absent on fourth abdominal tergum.

meybholae
Anal spines absent. Postantennal organ with 15 vesicles or more. Sensilla e3 and i2 of antennal segment iv are small, globular, not placed in cavity and not covered by tegumental fold. Setae a0 absent on the head. Setae m3 present on third thoracic tergum.

multilobata
Anal spines present. Apical vesicle simple. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Postantennal organ’s vesicles blackberry-shaped. Postantennal organ with 4 vesicles. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

nadchatrami
Fifth abdominal tergum with setae s in p3 position. First thoracic tergum with 2 + 2 setae, curved and crenellated. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum.

namibiae
Postantennal organ with 4 vesicles. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi iii with 120 setae. Tibiotarsi with 11 or 12 setae. Ventral tube with 5 + 5 setae.

neocaledonica
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Antennal segment iv with two or four subcylindrical sensilla clearly differentiated from ordinary setae. Antennal segment iv with four subcylindrical sensilla. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 10 to 15 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum. Third thoracic tergum with setae s m7 subcylindrical and acuminate. Tibiotarsi with 12 setae.

nepalensis
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Antennal segment iv with four subcylindrical sensilla hardly distinguishable from ordinary setae. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum. Third thoracic tergum with setae s m7 lanceolate. Tibiotarsi with 12 setae.

persimilis
Anal spines present. Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. First, second and third tibiotarsus with 14, 14 and 13 setae respectively. Postantennal organ with 7 vesicles or more. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 absent on abdominal terga ii and iii. Setae m1 and m3 absent on fourth abdominal tergum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

scandinavica
Empodial appendage present. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Sensilla d and i1 absent - i. e. d and i1 not differentiated from ordinary setae - on antennal segment iv. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 absent on fourth abdominal tergum.

setonychia
Anal spines absent. Antennal segment iv with ordinary setae, without lanceolate setae. Apical vesicle absent. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 18 to 20 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae m3 absent on third thoracic tergum.

similis
Anal lobes with 3 hr setae. Fifth abdominal tergum with setae s in p3 position - thus setae p2 present. Number of prelabral setae 2. Sensilla e1 present on antennal segment iv. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae m1 present on fourth abdominal tergum. Setae m3 absent on abdominal terga ii and iii.

subbulbosa
Anal spines present. Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. First, second and third tibiotarsus with 12, 12 and 11 setae respectively. Postantennal organ with 7 vesicles or more. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 present on abdominal terga ii and iii. Setae m1 and m3 present on fourth abdominal tergum. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

trilobata
Postantennal organ with 3 vesicles. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Tibiotarsi iii with 110 setae. Tibiotarsi with 11 or 12 setae. Ventral tube with 5 + 5 setae.

trisphaerae
Anal spines absent. Antennal segment iv with 3 sensilla - e2, e3 and i2 candle flame-shaped. Sensilla i1 and d absent on antennal segment iv - i. e. d and i1 not differentiated from ordinary setae. Sensilla on antennal segment iv, with another shape. Setae a0 present on the head. Setae a1 absent on fourth abdominal sternum. Setae a2 present on abdominal terga ii and iii. Tibiotarsi with more than 12 setae. Ventral tube with 4 + 40 setae.

virae
Fifth abdominal tergum with setae s in p2 position - thus setae p2 absent. M-row absent on fourth abdominal tergum. Setae a0 present on the head. Setae a1 present on fourth abdominal sternum. Setae a4 absent on second and third thoracic tergum.

wandae
Abdominal terga iv and v with setae s subcylindrical and acuminate. Anal spines present. Apical vesicle present. Fifth abdominal tergum with setae s in p2 position. First thoracic tergum with 3 + 3 setae. Postantennal organ with 12 to 14 vesicles. Sensilla e3 and i2 of antennal segment iv are large, globular, placed in cavity and covered in part by tegumental fold. Setae a0 absent on the head. Setae a3 absent on abdominal sterna ii and iv. Setae c1 absent on the head. Setae m3 absent on third thoracic tergum. Setae s m7 on third thoracic tergum lanceolate. Tibiotarsi i and ii with 11 setae, tibiotarsi iii with 11 or 10 setae.


References