http://www.collembola.org/key/hypoidea.htm - Last updated on 2009.09.30 by Frans Janssens
Checklist of the Collembola: Key to the families of Hypogastruroidea

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.

Kenneth A. Christiansen, Department of Biology, Grinnell College, PO Box V3, Grinnell, IA 50112-0806, USA
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). Sense organ of third antennal segment complex with at least six
        elements, 4-5 outer papillae and 1-3 inner sense structures
        (fig.1a).................................................... 2
      Sense organ of third antennal segment with at most two or three
        protective papillae and two inner sensory structures (fig.1b),
        or with the organ divided into a dorsal and ventral section,
        each bearing more than 2 structures......................... 3

Fig.1.
   
2(1). Abdomen with lateral projections (fig.2).......................
         .......................................... Pachytullbergiidae 2
      Abdomen without lateral projections............. Hypogastruridae 1

Fig.2.
   
3(1). Eyes absent, furcula or trace absent, unguiculi absent........ 4
      Eyes present, furcula or trace present.......... Hypogastruridae 2
 

4(3). Postantennal organ minute - about 4.6 micra - or absent....... 5
      Postantennal organ present, normal size....................... 6
 

5(4). Abdomen cylindrical; postantennal organ minute; sixth abdominal
        segment longer than fifth (fig.3b)........ Paleotullbergiidae
      Abdomen semi-ovoid; postantennal organ absent; sixth abdominal
        segment shorter than fifth (fig.3a).......... Hypogastruridae 3

Fig.3.
   
6(4). Postantennal organ elongate (fig.4)......... Pachytullbergiidae
      Postantennal organ not elongate................. Hypogastruridae

Fig.4.
  

Endnotes

1 Acherongia will key out here.

2 ad partem.

3 ad partem.

Differential diagnoses

Hypogastruridae
Eyes absent, furcula or trace absent, unguiculi absent. Postantennal organ present, normal size. Postantennal organ not elongate. Sense organ of third antennal segment with at most two or three protective papillae and two inner sensory structures (fig.1b), or with the organ divided into a dorsal and ventral section, each bearing more than 2 structures.

Hypogastruridae 1
Abdomen without lateral projections. Sense organ of third antennal segment complex with at least six elements, 4–5 outer papillae and 1–3 inner sense structures (fig.1a).

Hypogastruridae 2
Eyes present, furcula or trace present. Sense organ of third antennal segment with at most two or three protective papillae and two inner sensory structures (fig.1b), or with the organ divided into a dorsal and ventral section, each bearing more than 2 structures.

Hypogastruridae 3
Abdomen semi-ovoid. Eyes absent, furcula or trace absent, unguiculi absent. Postantennal organ minute - about 4.6 micra - or absent. Postantennal organ absent. Sense organ of third antennal segment with at most two or three protective papillae and two inner sensory structures (fig.1b), or with the organ divided into a dorsal and ventral section, each bearing more than 2 structures. Sixth abdominal segment shorter than fifth (fig.3a).

Pachytullbergiidae
Eyes absent, furcula or trace absent, unguiculi absent. Postantennal organ present, normal size. Postantennal organ elongate (fig.4). Sense organ of third antennal segment with at most two or three protective papillae and two inner sensory structures (fig.1b), or with the organ divided into a dorsal and ventral section, each bearing more than 2 structures.

Pachytullbergiidae 2
Abdomen with lateral projections (fig.2). Sense organ of third antennal segment complex with at least six elements, 4–5 outer papillae and 1–3 inner sense structures (fig.1a).

Paleotullbergiidae
Abdomen cylindrical. Eyes absent, furcula or trace absent, unguiculi absent. Postantennal organ minute - about 4.6 micra - or absent. Postantennal organ minute. Sense organ of third antennal segment with at most two or three protective papillae and two inner sensory structures (fig.1b), or with the organ divided into a dorsal and ventral section, each bearing more than 2 structures. Sixth abdominal segment longer than fifth (fig.3b).

References