http://www.collembola.org/key/pseudach.htm - Last updated on 2017.10.31 by Frans Janssens
Checklist of the Collembola: Key to the species of Pseudachorutes, partim Ukraine

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.

Ighor J. Kaprus, State Natural History Museum of NAS of Ukraine, UA-79008, L'viv, Ukraine
Wanda M. Weiner, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Pl-31 016 Kraków, Poland.
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 3 + 3 setae....................... 2
      First thoracic segment with 4 + 4 setae....................... 8
 
2(1). Claw with a strong lateral teeth in basal part (fig.1); fifth
        abdominal segment with p2 setae (fig.2); fourth abdominal
        segment with three m-setae and six a-setae (fig.2)... vitalii
      Claw without lateral teeth; fifth abdominal segment without p2
        setae; fourth abdominal segment without m-setae and with four
        a-setae..................................................... 3
 

Fig.1.
 

Fig.2.
 
3(2). Second thoracic segment with five setae in a-row, a5 present
        (fig.3a); tibiotarsi with one clavate or blunt tenent hair
        (fig.4a, b)................................................ 4
      Second thoracic segment without a5 setae (fig.3b); tibiotarsi
        with acuminate tenent hair (fig.4c)........................ 5
 

Fig.3.
 

Fig.4.
 
4(3). First to third abdominal segment with m4 setae; labium without
        organites-x and papillate setae L; median pair of prelabral
        setae present (fig.5a); tibiotarsi with one distinctly
        clavate tenent hair (fig.4a).................... corticicolus
      First to third abdominal segment without m4 setae; labium with 2
        + 2 organites-x and papillate setae L (fig.6); median pair of
        prelabral setae absent (fig.5b); tibiotarsi with one blunt
        tenent hair (fig.4b)............................... janstachi
 

Fig.5.
 

Fig.6.
 
5(3). Second thoracic segment with a2 setae (fig.7a)............... 6
      Second thoracic segment without a2 setae (fig.7b)............ 7
 

Fig.7.
 
6(5). Labral formula: 2/2, 3, 3, 4 (fig.8b); mandible with four
        teeth, medial tooth small, subapical tooth bigger than medial
        one (fig.9b); adult specimens without modified setae on
        fourth antennal segment.............................. parvulus
      Labral formula: 4/2, 3, 3, 4 (fig.8a); mandible with four
        teeth, two inner teeth are equal approximately (fig.9a);
        adult and subadults specimens with a group of 15-18 modified
        setae on the ventro-apical part of fourth antennal segment
        (fig.10)........................................... subcrassus
 

Fig.8.
 

Fig.9.
 

Fig.10.
 
7(5). Labium with B setae (fig.11a); d1 setae on head unpaired
        (fig.12a); fifth abdominal segment without a2 setae... vasylii
      Labium without B setae (fig.11b); d1 setae on head paired
        (fig.12b); fifth abdominal segment with a2 setae.... pratensis
 

Fig.11.
 

Fig.12.
 
8(1). Fourth abdominal segment with m1 setae and six setae in a-row
        (fig.13a); labium with 2 + 2 organites-x and papillate setae L
        (fig.14a).......................................... palmiensis
      Fourth abdominal segment without m1 setae and with four setae in
        a-row (fig.13b); labium without organites-x and papillate
        setae L (fig.14b)........................................... 9
 

Fig.13.
 

Fig.14.
 
9(8). Fifth abdominal segment with p2 setae; fourth abdominal segment
        with two m-setae; postantennal organ with 14-20 vesicles;
        second thoracic segment without a2 setae............... dubius
      Fifth abdominal segment without p2 setae (fig.13b); fourth
        abdominal segment without m-setae (fig.13b); postantennal
        organ with 10-12 vesicles (fig.15); second thoracic segment
        with a2 setae (fig.16)............................... scythicus

Fig.15.
 

Fig.16.
 


Differential diagnoses

corticicolus
Claw without lateral teeth. Fifth abdominal segment without p2 setae. First thoracic segment with 3 + 3 setae. First to third abdominal segment with m4 setae. Fourth abdominal segment without m-setae and with four a-setae. Labium without organites-x and papillate setae L. Median pair of prelabral setae present (fig.5a). Second thoracic segment with five setae in a-row, a5 present (fig.3a). Tibiotarsi with one clavate or blunt tenent hair (fig.4a, b). Tibiotarsi with one distinctly clavate tenent hair (fig.4a).

dubius
Fifth abdominal segment with p2 setae. First thoracic segment with 4 + 4 setae. Fourth abdominal segment without m1 setae and with four setae in a-row (fig.13b). Fourth abdominal segment with two m-setae. Labium without organites-x and papillate setae L (fig.14b). Postantennal organ with 14–20 vesicles. Second thoracic segment without a2 setae.

janstachi
Claw without lateral teeth. Fifth abdominal segment without p2 setae. First thoracic segment with 3 + 3 setae. First to third abdominal segment without m4 setae. Fourth abdominal segment without m-setae and with four a-setae. Labium with 2 + 2 organites-x and papillate setae L (fig.6). Median pair of prelabral setae absent (fig.5b). Second thoracic segment with five setae in a-row, a5 present (fig.3a). Tibiotarsi with one clavate or blunt tenent hair (fig.4a, b). Tibiotarsi with one blunt tenent hair (fig.4b).

palmiensis
First thoracic segment with 4 + 4 setae. Fourth abdominal segment with m1 setae and six setae in a-row (fig.13a). Labium with fig. + 2 organites-x and papillate setae L (fig.14a).

parvulus
Adult specimens without modified setae on fourth antennal segment. Claw without lateral teeth. Fifth abdominal segment without p2 setae. First thoracic segment with 3 + 3 setae. Fourth abdominal segment without m-setae and with four a-setae. Labral formula: 2/2, 3, 3, 4 (fig.8b). Mandible with four teeth, medial tooth small, subapical tooth bigger than medial one (fig.9b). Second thoracic segment without a5 setae (fig.3b). Second thoracic segment with a2 setae (fig.7a). Tibiotarsi with acuminate tenent hair (fig.4c).

pratensis
Claw without lateral teeth. D1 setae on head paired (fig.12b). Fifth abdominal segment without p2 setae. Fifth abdominal segment with a2 setae. First thoracic segment with 3 + 3 setae. Fourth abdominal segment without m-setae and with four a-setae. Labium without B setae (fig.11b). Second thoracic segment without a5 setae (fig.3b). Second thoracic segment without a2 setae (fig.7b). Tibiotarsi with acuminate tenent hair (fig.4c).

scythicus
Fifth abdominal segment without p2 setae (fig.13b). First thoracic segment with 4 + 4 setae. Fourth abdominal segment without m1 setae and with four setae in a-row (fig.13b). Fourth abdominal segment without m-setae (fig.13b). Labium without organites-x and papillate setae L (fig.14b). Postantennal organ with 10–12 vesicles (fig.15). Second thoracic segment with a2 setae (fig.16).

subcrassus
Adult and subadults specimens with a group of 15–18 modified setae on the ventro-apical part of fourth antennal segment (fig.10). Claw without lateral teeth. Fifth abdominal segment without p2 setae. First thoracic segment with 3 + 3 setae. Fourth abdominal segment without m-setae and with four a-setae. Labral formula: 4/2, 3, 3, 4 (fig.8a). Mandible with four teeth, two inner teeth are equal approximately (fig.9a). Second thoracic segment without a5 setae (fig.3b). Second thoracic segment with a2 setae (fig.7a). Tibiotarsi with acuminate tenent hair (fig.4c).

vasylii
Claw without lateral teeth. D1 setae on head unpaired (fig.12a). Fifth abdominal segment without p2 setae. Fifth abdominal segment without a2 setae. First thoracic segment with 3 + 3 setae. Fourth abdominal segment without m-setae and with four a-setae. Labium with B setae (fig.11a). Second thoracic segment without a5 setae (fig.3b). Second thoracic segment without a2 setae (fig.7b). Tibiotarsi with acuminate tenent hair (fig.4c).

vitalii
Claw with a strong lateral teeth in basal part (fig.1). Fifth abdominal segment with p2 setae (fig.2). First thoracic segment with 3 + 3 setae. Fourth abdominal segment with three m-setae and six a-setae (fig.2).


References