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

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.

Arne Fjellberg, Mageroveien 168, N-3145 Tjome, Norway
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). Hypostomal seta H not reduced, almost as long as h1-h2 (fig.1a);
        labrum with 4 low ridges (fig.2a); maxillary lamella 1 with
        two ciliated fringes (fig.3a)............................... 2
      Hypostomal seta H reduced to a small papilla (fig.1b); labrum
        with 4 finger-like projections (fig.2b); maxillary lamella 1
        with 5-6 ciliated fringes (fig.3b)................... maritima
 

Fig.1.
 

Fig.2.
 

Fig.3.
 
2(1). Frontoclypeal field in adults with more than 10 setae;
        microsensilla present on all segments second thoracic segment
        to third abdominal segment, ms formula 11/111............... 3
      Frontoclypeal field usually with only 4 setae, sometimes 1-2
        additionals (fig.4); microsensilla absent from third thoracic
        segment and second abdominal segment, ms formula 10/101
        (fig.5)............................................. arenicola
 

Fig.4.
 

Fig.5.
 
3(2). Claw normal, lateral teeth small (fig.6b); retinaculum in adults
        with two setae (fig.7); third tibiotarsus with seta A7 thicker
        than A1 (fig.6b)....................................... boneti
      Claw strongly curved, lateral teeth large (fig.6a); retinaculum
        in adults with more than two setae; third tibiotarsus with
        seta A7 slender, not thicker than A1 (fig.6a)...... poseidonis

Fig.6.
 

Fig.7.
 


Differential diagnoses

arenicola
Frontoclypeal field usually with only 4 setae, sometimes 1–2 additionals (fig.4). Hypostomal seta H not reduced, almost as long as h1-h2 (fig.1a). Labrum with 4 low ridges (fig.2a). Maxillary lamella 1 with two ciliated fringes (fig.3a). Microsensilla absent from third thoracic segment and second abdominal segment, ms formula 10/101 (fig.5).

boneti
Claw normal, lateral teeth small (fig.6b). Frontoclypeal field in adults with more than 10 setae. Hypostomal seta H not reduced, almost as long as h1-h2 (fig.1a). Labrum with 4 low ridges (fig.2a). Maxillary lamella 1 with two ciliated fringes (fig.3a). Microsensilla present on all segments second thoracic segment to third abdominal segment, ms formula fig./111. Retinaculum in adults with two setae (fig.7). Third tibiotarsus with seta A7 thicker than A1 (fig.6b).

maritima
Hypostomal seta H reduced to a small papilla (fig.1b). Labrum with 4 finger-like projections (fig.2b). Maxillary lamella 1 with fig.4–6 ciliated fringes (fig.3b).

poseidonis
Claw strongly curved, lateral teeth large (fig.6a). Frontoclypeal field in adults with more than 10 setae. Hypostomal seta H not reduced, almost as long as h1-h2 (fig.1a). Labrum with 4 low ridges (fig.2a). Maxillary lamella 1 with two ciliated fringes (fig.3a). Microsensilla present on all segments second thoracic segment to third abdominal segment, ms formula 11/111. Retinaculum in adults with more than two setae. Third tibiotarsus with seta A7 slender, not thicker than A1 (fig.6a).


References