http://www.collembola.org/key/archtoma.htm - Last updated on 2009.09.30 by Frans Janssens
Checklist of the Collembola: Key to the species of Archisotoma

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.

Jean-Marc Thibaud, Laboratoire d'Entomologie, Museum National d'Histoire Naturelle, 75005 Paris, France
José G. Palacios-Vargas, Departamento de Biologia, Universidad Nacional Autónoma de México, 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).   Manubrium with setae........................................ 2
        Manubrium without setae.............................. pauliani
 
2(1).   Postantennal organ long, six times the length of closest eye..
           ................................................. nigricans
        Postantennal organ normal, two to four times the length of the
          closest eye............................................... 3
 
3(2).   Eyes absent; fifth and sixth abdominal segment without
          trichobothria.................................. heraultensis
        Eyes present; fifth and sixth abdominal segment with 2 or 3
          pairs of trichobothria.................................... 4
 
4(3).   Trichobothria in three pairs ta, tm and tl, almost in
          transversal position, one seta between ta and tm.......... 5
        Trichobothria in two pairs ta and tp, almost in diagonal
          position, two or three setae between ta and tp........... 14
 
5(4).   Third tibiotarsus with dorso-apical spine................... 6
        Third tibiotarsus without dorso-apical spine............... 11
 
6(5).   Eyes eigth by side, often two of them reduced; dens elongated
          with 10 setae or more..................................... 7
        Eyes two by side; dens short with 3 setae....... quadrioculata
 
7(6).   Prelabral 12 setae..................................... brucei
        Prelabral at most 5 setae................................... 8
 
8(7).   Dens with 10 to 12 setae; prelabral 2 setae................. 9
        Dens with more than 25 setae; prelabral 4-5 setae.......... 10
 
9(8).   Manubrium with 18 setae; mucro with 1 seta............. martae
        Manubrium with about 10 setae; mucro without setae...... theae
 
10(8).  Length 0.5 mm; manubrium with about 20 setae; dens with 36
          setae............................................. poinsotae
        Length 1.0-1.5 mm; manubrium with about 32 setae; dens with
          26-30 setae........................................ besselsi
 
11(5).  Prelabral six or more setae................................ 12
        Prelabral two setae................................. pulchella
 
12(11). Prelabral six to nine setae................................ 13
        Prelabral twenty setae............................... megalops
 
13(12). On front of the head 6-7 setae; postantennal organ 2.9 times
          the diameter of anterior eye........................ polaris
        On front of the head 8-9 setae; postantennal organ 1.8 times
          the diameter of anterior eye......................... vareli
 
14(4).  Length about 0.5 mm; prelabral two setae; ventral tube with 4
          setae on each side....................................... 15
        Length about 1 mm; prelabral four setae in two rows; ventral
          tube with 4 or 6 setae on each side...................... 18
 
15(14). Eyes 5 per side, two of them reduced................. sabulosa
        Eyes 6, 7 or 8 per side usually one or two reduced and
          difficult to see......................................... 16
 
16(15). Between the two trichobothria ta five or six setae......... 17
        Between the two trichobothria ta two or three setae. litoralis
 
17(16). Dens with 18 setae; anterior subcoxa furcalis with 13-17
          setae; posterior subcoxa furcalis with 11-14 setae. vaoensis
        Dens with 20-24 setae; anterior subcoxa furcalis with 19-21
          setae; posterior subcoxa furcalis with 15-18 setae..........
           ............................................... gourbaultae
 
18(14). Length 0.8-1.1 mm; manubrium with about twenty to thirty
          setae; dens with about twenty to thirty setae; ventral tube
          with 4 setae on each side.................... interstitialis
        Length 1.0-1.5 mm; manubrium with about twenty setae; dens
          with about fourty setae; ventral tube with 6 setae on each
          side............................................... utinomii

Differential diagnoses

besselsi
Dens elongated with 10 setae or more. Dens with more than 25 setae. Dens with 26–30 setae. Eyes eigth by side, often two of them reduced. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length 1.0–1.5 mm. Manubrium with setae. Manubrium with about 32 setae. Mucro with 1 seta 160b mucro with 1 seta. Postantennal organ normal, two to four times the length of the closest eye. Prelabral at most 5 setae. Prelabral 4–5 setae. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

brucei
Dens elongated with 10 setae or more. Eyes eigth by side, often two of them reduced. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral 12 setae. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

gourbaultae
Anterior subcoxa furcalis with 19–21 setae. Between the two trichobothria ta five or six setae. Dens with 20–24 setae. Eyes present. Eyes 6, 7 or 8 per side usually one or two reduced and difficult to see. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length about 0.5 mm. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Posterior subcoxa furcalis with 15–18 setae. Prelabral two setae. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 setae on each side.

heraultensis
Eyes absent. Fifth and sixth abdominal segment without trichobothria. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye.

interstitialis
Dens with about twenty to thirty setae. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length 0.8–1.1 mm. Length about 1 mm. Manubrium with setae. Manubrium with about twenty to thirty setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral four setae in two rows. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 or 6 setae on each side. Ventral tube with 4 setae on each side.

litoralis
Between the two trichobothria ta two or three setae. Eyes present. Eyes 6, 7 or 8 per side usually one or two reduced and difficult to see. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length about 0.5 mm. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral two setae. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 setae on each side.

martae
Dens elongated with 10 setae or more. Dens with 10 to 12 setae. Eyes eigth by side, often two of them reduced. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Manubrium with 18 setae. Mucro with 1 seta. Postantennal organ normal, two to four times the length of the closest eye. Prelabral at most 5 setae. Prelabral 2 setae. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

megalops
Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral six or more setae. Prelabral twenty setae. Third tibiotarsus without dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

nigricans
Manubrium with setae. Postantennal organ long, six times the length of closest eye.

pauliani
Manubrium without setae.

poinsotae
Dens elongated with 10 setae or more. Dens with more than 25 setae. Dens with 36 setae. Eyes eigth by side, often two of them reduced. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length 0.5 mm. Manubrium with setae. Manubrium with about 20 setae. Mucro with 1 seta 160b mucro with 1 seta. Postantennal organ normal, two to four times the length of the closest eye. Prelabral at most 5 setae. Prelabral 4–5 setae. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

polaris
Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. On front of the head 6–7 setae. Postantennal organ 2.9 times the diameter of anterior eye. Postantennal organ normal, two to four times the length of the closest eye. Prelabral six or more setae. Prelabral six to nine setae. Third tibiotarsus without dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

pulchella
Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral two setae. Third tibiotarsus without dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

quadrioculata
Dens short with 3 setae. Eyes two by side. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

sabulosa
Eyes present. Eyes 5 per side, two of them reduced. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length about 0.5 mm. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral two setae. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 setae on each side.

theae
Dens elongated with 10 setae or more. Dens with 10 to 12 setae. Eyes eigth by side, often two of them reduced. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. Manubrium with about 10 setae. Mucro without setae. Postantennal organ normal, two to four times the length of the closest eye. Prelabral at most 5 setae. Prelabral 2 setae. Third tibiotarsus with dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

utinomii
Dens with about fourty setae. Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length 1.0–1.5 mm. Length about 1 mm. Manubrium with setae. Manubrium with about twenty setae. Postantennal organ normal, two to four times the length of the closest eye. Postlabial 7–8 pairs of setae 60b postlabial 7–8 pairs of setae. Prelabral four setae in two rows. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 or 6 setae on each side. Ventral tube with 6 setae on each side.

vaoensis
Anterior subcoxa furcalis with 13–17 setae. Between the two trichobothria ta five or six setae. Dens with 18 setae. Eyes present. Eyes 6, 7 or 8 per side usually one or two reduced and difficult to see. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Length about 0.5 mm. Manubrium with setae. Postantennal organ normal, two to four times the length of the closest eye. Posterior subcoxa furcalis with 11–14 setae. Prelabral two setae. Trichobothria in two pairs ta and tp, almost in diagonal position, two or three setae between ta and tp. Ventral tube with 4 setae on each side.

vareli
Eyes present. Fifth and sixth abdominal segment with 2 or 3 pairs of trichobothria. Manubrium with setae. On front of the head 8–9 setae. Postantennal organ 1.8 times the diameter of anterior eye. Postantennal organ normal, two to four times the length of the closest eye. Prelabral six or more setae. Prelabral six to nine setae. Third tibiotarsus without dorso-apical spine. Trichobothria in three pairs ta, tm and tl, almost in transversal position, one seta between ta and tm.

References