Ian R. Walker
Walker, I.R. (1988). Late-Quaternary Palaeoecology of Chironomidae (Insecta: Diptera) in Lake Sediments from British Columbia. Ph.D. thesis, Simon Fraser University, Burnaby, B.C.
Like other members of the subtribe Zavreliina, Stempellina have a pair of widely-separated, broad, fan-shaped ventromental plates, and prominent antennal pedestals. All Zavreliina also bear one or more prominent apical projections on each antennal pedestal. In Stempellina several projections are present, forming a prominent palmate process.
The Zavreliina reside in portable cases, and use these antennal projections to aid in dragging the cases across the lake or stream bottom.
Members of the subtribe Tanytarsina have prominent antennal pedestals, like those of the Zavreliina. Sometimes an apical projection is present on each antennal pedestal, but generally these are much smaller than those characteristic of the Zavreliina. In Cladotanytarsus and many other taxa, these projections are entirely absent.
In the Tanytarsina the median points of the ventromental plates nearly touch at the centre of the mentum. The ventromental plates are rectangular, or bar-shaped - not fan-shaped.
Like all members of the Chironomini, Stenochironomus lacks prominent antennal pedestals; however, note that Stenochironomus differs from all other representatives of the subfamily Chironominae in having very poorly developed (vestigial) ventromental plates. The concave mentum is another unusual feature, occurring only in a few other genera of chironomids (e.g., Cryptochironomus).
Stenochironomus larvae burrow in submerged wood.
Cryptochironomus is a typical member of the tribe Chironomini. The antennae are not borne on prominent pedestals. The ventromental plates in the Chironomini are fan-shaped (apart from Apedilum), and (apart from Apedilum, Lauterborniella and Zavreliella) widely separated.
Like the Chironomini, the antennae of the Pseudochironomini are not borne on prominent pedestals. However, unlike the Chironomini, the ventromental plates tend to be bar-shaped. The median apices of the ventromental plates nearly touch along the midline of the head capsule. In most species the 2nd lateral teeth are greatly reduced.
Cladotanytarsus is somewhat similar, but has prominent antennal pedestals, a more weakly pigmented mentum, and the 2nd lateral teeth are less noticeably reduced. Furthermore, unlike Pseudochironomus, there are no broadly rounded lateral bulges on either side of the mentum in Cladotanytarsus.
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Last Update: 10 February 1999