Key to Genera in the Tribe Chironomini

Ian R. Walker & K. Brodersen

Recommended Citation:
Walker, I. R., and K. Brodersen, 1997. Key to genera in the tribe Chironomini. Part IV. In: I. R. Walker (Ed.), The WWW Field Guide to Fossil Midges. (http://www.paleolab.ca/wwwguide/chironomini/even.htm)

Last Update: 1 June 1997

©2007 Ian R. Walker. ALL RIGHTS RESERVED

- a) Median and 1st lateral pairs of mental teeth more weakly pigmented than other mental teeth; 16 mental teeth (Fig. 1)
  .............................................................................Paratendipes
- b) Either all mental teeth weakly pigmented (Fig. 2), or with fewer than 4 weakly-pigmented teeth; 14 to 16 teeth (Fig. 6)
  .............................................................................2.
- a) Median pair, and second lateral pair of mental teeth distinctly longer than 1st lateral teeth (Fig. 2, 6)
  .............................................................................3.
- b) Median pair of teeth shorter, or subequal to length of adjacent pair (Fig. 9, 15)
  .............................................................................8.
- a) Mentum with 16 teeth (Fig. 2).
  .............................................................................4.
- b) Mentum with fewer teeth (Fig. 4).
  .............................................................................5.
- a) All mental teeth small, weakly pigmented; lateral extremity of ventromental plates rounded (Fig. 2)
  .............................................................................Pagastiella
- b) Mental teeth of normal size, brown to black; lateral extremity of ventromental plates pointed (Fig. 3).
  .............................................................................Polypedilum
- a) All teeth of mentum similarly pigmented (Fig. 4)
  .............................................................................6.
- b) Median teeth weakly pigmented relative to the lateral pairs of teeth (Fig. 6).
  .............................................................................7.
- a) All mental teeth weakly pigmented; anterior margin of ventromental plates nearly straight, almost meeting at median axis (Fig. 4)
  .............................................................................Lauterborniella/Zavreliella
- b) All mental teeth darkly pigmented; anterior margin of ventromental plates distinctly convex, widely separated (Fig. 5).
  .............................................................................Genus near Polypedilum?
- a) Ventromental plates distinctly fan-shaped, widely separated (Fig. 6)
  .............................................................................Microtendipes
- b) Ventromental plates appear bar-shaped, nearly meeting at median axis (Fig. 7).
  .............................................................................Apedilum
- a) Median pair of mental teeth much smaller than 1st lateral pair (Fig. 9)
  .............................................................................9.
- b) Median and 1st lateral teeth subequal (Fig. 15).
  .............................................................................10.
- a) Ventromental plates distinctly striated (Fig. 8)
  .............................................................................Omisus
- b) Striations of ventromental plates indistinct or absent (Fig. 9).
  .............................................................................Stictochironomus type B
- a) Ventromental plates separated by 6 or more teeth, distinctly and coarsely striated throughout (Fig. 10)
  .............................................................................Cyphomella/Harnischia/Paracladopelma group
- b) Ventromental plates separated by 4 or fewer teeth, distinctly or indistinctly striated (Fig. 15).
  .............................................................................11.
- a) Striations readily apparent in both the anterior and median fields of the ventromental plates (Fig. 13)
  .............................................................................12.
- b) Striations not apparent in median field of the ventromental plates (Fig. 15).
  .............................................................................14.
- a) Ventromental plates sweeping very far laterally away from mentum (Fig. 11)
  .............................................................................Endochironomus
- b) Ventromental plates of normal fan shape (Fig. 13).
  .............................................................................13.
- a) ???? (Fig. 12)
  .............................................................................Tribelos
- b) ???? (Fig. 13).
  .............................................................................Phaenopsectra cf. flavipes
- a) Striations very weak or absent in anterior field of ventromental plates (Fig. 14); 3rd lateral teeth of mentum of normal size; mandibles with 2 or 3 inner teeth
  .............................................................................Stictochironomus type A
- b) Striae near anterior ventromental margin distinct and widely spaced (adjacent striations are separated by about their apparent length) (Fig. 15); 3rd lateral teeth of mentum larger than adjacent pairs in most specimens; mandibles with 4 inner teeth.
  .............................................................................Sergentia