http://www.collembola.org/key/onychiur.htm - Last updated on 2024.10.31 by Frans Janssens
Checklist of the Collembola: Key to the species of Onychiurus

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.

Javier Arbea C/ Ría de Solía 3, ch. 39, 39610 El Astillero, Spain
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).   First thoracic segment with dorsal pseudocelli.............. 2
        First thoracic segment without dorsal pseudocelli.......... 24
 
2(1).   First to third thoracic segment with 1 or 2, 3 or 2, 3 or 2
          dorsal pseudocelli........................................ 3
        First to third thoracic segment with 3, 3, 5 dorsal
          pseudocelli......................................... willemi
 
3(2).   Fifth abdominal segment with 3 + 3 dorsal pseudocelli....... 4
        Fifth abdominal segment with 4 + 4 dorsal pseudocelli...... 19
 
4(3).   Fourth abdominal segment with 3 + 3 dorsal pseudocelli........
           ............................................. polychaetosus
        Fourth abdominal segment with more dorsal pseudocelli....... 5
 
5(4).   Fourth abdominal segment with 4 + 4 dorsal pseudocelli...... 6
        Fourth abdominal segment with 5 + 5 dorsal pseudocelli..... 10
 
6(5).   Head with 1 + 1 ventral pseudocelli.............. decemsetosus
        Head with 2 + 2 ventral pseudocelli......................... 7
 
7(6).   Fourth abdominal segment with 1 + 1 ventral pseudocelli..... 8
        Fourth abdominal segment with 2 + 2 ventral pseudocelli..... 9
 
8(7).   First abdominal segment with 2 + 2 ventral pseudocelli........
           ............................................... subambulans 1
        First abdominal segment without ventral pseudocelli...........
           ................................................ antennalis
 
9(7).   Second abdominal segment with 1 + 1 ventral pseudocelli.......
           ................................................. ariegicus
        Second abdominal segment with 2 + 2 ventral pseudocelli.......
           .................................................. ambulans 2
 
10(5).  Head with 2 + 2 ventral pseudocelli........................ 11
        Head with 3 + 3 ventral pseudocelli........................ 16
 
11(10). Fourth abdominal segment with 1 + 1 ventral pseudocelli.......
           ............................................... subambulans 3
        Fourth abdominal segment with 2 + 2 ventral pseudocelli.... 12
 
12(11). First abdominal segment with 1 + 1 ventral pseudocelli..... 13
        First abdominal segment with 2 + 2 ventral pseudocelli........
           ................................................. circulans 4
 
13(12). Second abdominal segment with 1 + 1 ventral pseudocelli.... 14
        Second abdominal segment with 2 + 2 ventral pseudocelli.......
           .............................................. furcisetosus
 
14(13). Dorsal macrochaetae apically rounded............... confugiens
        Dorsal macrochaetae forked at the tip...................... 15
 
15(14). Formula of parapseudocelli on abdominal sterna as 101003;
          males with ventral organ...................... rectospinatus
        Formula of parapseudocelli on abdominal sterna as 111003;
          males without ventral organ........................ reluctus
 
16(10). First to third thoracic segment with 0, 1, 1 ventral
          pseudocelli.............................................. 17
        First to third thoracic segment without ventral pseudocelli...
           ............................................... dissimulans
 
17(16). Third abdominal segment with 1 + 1 ventral pseudocelli..... 18
        Third abdominal segment with 2 + 2 ventral pseudocelli........
           .............................................. subcirculans
 
18(17). Second abdominal segment with 1 + 1 ventral pseudocelli.......
           ................................................... movilae
        Second abdominal segment with 2 + 2 ventral pseudocelli.......
           .................................................. ambulans 5
 
19(3).  Fourth abdominal segment with 5 + 5 dorsal pseudocelli..... 20
        Fourth abdominal segment with 6 + 6 dorsal pseudocelli........
           ................................................. penetrans
 
20(19). Head with 2 + 2 ventral pseudocelli........................ 21
        Head with 3 + 3 ventral pseudocelli........................ 22
 
21(20). First to fourth abdominal segment with 1, 2, 1, 1 ventral
          pseudocelli..................................... reluctoides
        First to fourth abdominal segment with 2, 2, 2, 1 ventral
          pseudocelli........................................... ortus
 
22(20). Fourth abdominal segment with 1 + 1 ventral pseudocelli.......
           ................................................. sublegans
        Fourth abdominal segment with 2 + 2 ventral pseudocelli.... 23
 
23(22). Third abdominal segment with 1 + 1 ventral pseudocelli.. arans
        Third abdominal segment with 2 + 2 ventral pseudocelli........
           ................................................. insinuans
 
24(1).  First to third thoracic segment with 0, 2, 2 dorsal
          pseudocelli.............................................. 25
        First to third thoracic segment with 0, 3, 3 dorsal
          pseudocelli.............................................. 29
 
25(24). Fourth abdominal segment with 3 + 3 dorsal pseudocelli. wilchi
        Fourth abdominal segment with more dorsal pseudocelli...... 26
 
26(25). Fourth abdominal segment with 4 + 4 dorsal pseudocelli........
           ................................................ gulinensis
        Fourth abdominal segment with 5 + 5 dorsal pseudocelli..... 27
 
27(26). First abdominal segment with 1 + 1 ventral pseudocelli..... 28
        First abdominal segment without ventral pseudocelli. saphianus
 
28(27). Fourth abdominal segment with 2 + 2 ventral pseudocelli.......
           ................................................ steinmanni
        Fourth abdominal segment without ventral pseudocelli.. bhattii
 
29(24). Fourth abdominal segment with 3 + 3 dorsal pseudocelli..... 30
        Fourth abdominal segment with more dorsal pseudocelli...... 37
 
30(29). First to third abdominal segment with 3, 3, 3 dorsal
          pseudocelli.............................................. 31
        First to third abdominal segment with 4, 4, 4 dorsal
          pseudocelli......................................... gevorum
 
31(30). Sense organ of third antennal segment with 4 papillae...... 32
        Sense organ of third antennal segment with 5 papillae...... 33
 
32(31). Formula of parapseudocelli on abdominal sterna as 11100; ratio
          length anal spine versus inner edge of third claw 1.00-1,
          27.................................................. vtorovi
        Formula of parapseudocelli on abdominal sterna as 11101; ratio
          length anal spine versus inner edge of third claw 0.66-1.00.
           ..................................................... darii
 
33(31). First thoracic segment with 6 + 6 dorsal chaetae; distal whorl
          on tibiotarsi with 7 chaetae............................. 34
        First thoracic segment with 7 + 7 dorsal chaetae; distal whorl
          on tibiotarsi with 9 chaetae......................... jaceki
 
34(33). Sense organ of third antennal segment with 4 guard chaetae. 35
        Sense organ of third antennal segment with 5 guard chaetae....
           ................................................ sarmaticus
 
35(34). Ventral tube with 1 + 1 chaetae at base.............. obsiones
        Ventral tube without chaetae at base....................... 36
 
36(35). Chaeta a3 longer than a1; fifth abdominal segment tergum with
          a3 as macrochaetae; empodial appendage half as long as inner
          edge of claw..................................... szeptyckii
        Chaeta a3 shorter than a1; fifth abdominal segment tergum with
          a3 as microchaetae; empodial appendage as long as inner edge
          of claw...................................... orienteuropeus
 
37(29). Fourth abdominal segment with 4 + 4 dorsal pseudocelli..... 38
        Fourth abdominal segment with 5 + 5 dorsal pseudocelli..... 39
 
38(37). First to third thoracic segment with 1, 1, 1 ventral
          pseudocelli..................................... stillicidii
        First to third thoracic segment without ventral pseudocelli...
           .................................................. boldorii
 
39(37). Empodial lamella absent; first and second abdominal segment
          with 2 + 2 ventral pseudocelli.................... paolettii
        Empodial lamella present; first and second abdominal segment
          with 1 + 1 ventral pseudocelli................... nathanieli

Endnotes

1 Ad partem.

2 Sensu Stach, 1934 & Gisin, 1956.

3 Ad partem.

4 From Madeira.

5 Sensu Pomorski, 1998. O. circulans not from Madeira will key out here also.

References