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

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.

Dariusz Skarzynski, Zoological Institute, Wroclaw University, 51-148 Wroclaw, 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). Retinaculum quadridentate or rarely tridentate; tibiotarsi with
        1 clavate or pointed tenent hair............................ 2
      Retinaculum tridentate; tibiotarsi with more than 1 clavate
        tenent hair..................................... viatica-group
 

2(1). Labrum with 4-6 distal papillae............................... 3
      Labrum without distal papillae................................ 8
 

3(2). Fourth antennal segment with 3 dorsal and 2-3 lateral weakly
        differentiated sensilla (fig.1); m-setae on fifth abdominal
        tergum present; postantennal organ 1.5-2 times larger than the
        adjacent ocelli............................... monticola-group
      Fourth antennal segment with 3 dorsal and 3-14 lateral well
        differentiated sensilla; m-setae on fifth abdominal tergum
        absent; postantennal organ slightly smaller than adjacent
        ocelli...................................................... 4

Fig.1.
   
4(3). Mucro with distinct subapical tooth; dens with tooth-like
        granules in distal part and prominent ventro-apical swelling..
         ........................................................... 5
      Mucro without distinct subapical tooth; dens without tooth-like
        granules and prominent ventro-apical swelling............... 6
 

5(4). Distribution nearctic............................ nivicola-group
      Distribution palaearctic......................... socialis-group
 

6(4). Body granulation coarse: 3-6 granules between setae p1 on fifth
        abdominal tergum....................... crassaegranulata-group
      Body granulation fine: more than 6 granules between setae p1 on
        fifth abdominal tergum...................................... 7
 

7(6). Distribution nearctic............................ packardi-group
      Distribution palaearctic........................ sahlbergi-group
 

8(2). Empodial appendage with broad basal lamella; setae m6 on
        mesothoracic and metathoracic terga present..... trybomi-group
      Empodial appendage with narrow basal lamella; setae m6 on
        mesothoracic and metathoracic terga absent.. manubrialis-group

Differential diagnoses

crassaegranulata-group
Body granulation coarse: 3–6 granules between setae p1 on fifth abdominal tergum. Dens without tooth-like granules and prominent ventro-apical swelling. Fourth antennal segment with 3 dorsal and 3–14 lateral well differentiated sensilla. Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum absent. Mucro without distinct subapical tooth. Postantennal organ slightly smaller than adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

manubrialis-group
Empodial appendage with narrow basal lamella. Labrum without distal papillae. Retinaculum quadridentate or rarely tridentate. Setae m6 on mesothoracic and metathoracic terga absent. Tibiotarsi with 1 clavate or pointed tenent hair.

monticola-group
Fourth antennal segment with 3 dorsal and fig.–3 lateral weakly differentiated sensilla (fig.1). Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum present. Postantennal organ 1.5–2 times larger than the adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

nivicola-group
Dens with tooth-like granules in distal part and prominent ventro-apical swelling. Distribution nearctic. Fourth antennal segment with 3 dorsal and 3–14 lateral well differentiated sensilla. Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum absent. Mucro with distinct subapical tooth. Postantennal organ slightly smaller than adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

packardi-group
Body granulation fine: more than 6 granules between setae p1 on fifth abdominal tergum. Dens without tooth-like granules and prominent ventro-apical swelling. Distribution nearctic. Fourth antennal segment with 3 dorsal and 3–14 lateral well differentiated sensilla. Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum absent. Mucro without distinct subapical tooth. Postantennal organ slightly smaller than adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

sahlbergi-group
Body granulation fine: more than 6 granules between setae p1 on fifth abdominal tergum. Dens without tooth-like granules and prominent ventro-apical swelling. Distribution palaearctic. Fourth antennal segment with 3 dorsal and 3–14 lateral well differentiated sensilla. Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum absent. Mucro without distinct subapical tooth. Postantennal organ slightly smaller than adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

socialis-group
Dens with tooth-like granules in distal part and prominent ventro-apical swelling. Distribution palaearctic. Fourth antennal segment with 3 dorsal and 3–14 lateral well differentiated sensilla. Labrum with 4–6 distal papillae. M-setae on fifth abdominal tergum absent. Mucro with distinct subapical tooth. Postantennal organ slightly smaller than adjacent ocelli. Retinaculum quadridentate or rarely tridentate. Tibiotarsi with 1 clavate or pointed tenent hair.

trybomi-group
Empodial appendage with broad basal lamella. Labrum without distal papillae. Retinaculum quadridentate or rarely tridentate. Setae m6 on mesothoracic and metathoracic terga present. Tibiotarsi with 1 clavate or pointed tenent hair.

viatica-group
Retinaculum tridentate. Tibiotarsi with more than 1 clavate tenent hair.

References