Species 4i. Chironomus (Lobochironomus) pseudomendax(?), Wülker 1998

This North American material was initially identified as C. mendax by W. Wülker in Ryser et al. (1985).  However, the Palearctic material was subsequently shown not to be C. mendax Storå, and given the new name "pseudomendax" by Wülker (1998), on the basis of a difference in chromosome number.  Although not specifically stated, the larval mentum of the North American material was apparently similar to that of C. pseudomendax, not like that of C. mendax.  Since the cytology of the North American material is not known, it is not certain as to what species it really belongs.


The superior volsella is rather similar to that of Einfeldia species, but the narrower curved lobe arises from the dorsal surface near its base, whereas in Einfeldia it arises apically or subapically from the ventral lobe (Grodhaus and Ferrington 1989).

Pupa:  Not described, but may be some specimens in the collection of the Kansas Biological Survey (Grodhaus and Ferrington (1989), and that of Palearctic specimens is given in Langton and Visser (2003).  The hook row of tergite II is interrupted.  The spur of segment VIII has 1 or 2 spines.

Fourth instar larva:  Apparently similar to that of European C. pseudomendax, i.e. a plumosus-type larva with unpigmented head capsule.  Posterolateral tubules longer than 150 µm
c2 teeth of central trifid tooth of mentum relatively well separated (perhaps type III), as are the 1st laterals.
Antennal segments (µm) A1 109-136 : A2 31-44; Ring organ a quarter to a third up from base of segment A1.

Cytology:  Not known for North American material. If it is C. pseudomendax it will have 4 polytene chromosomes with the thummi-cytocomplex combination AB, CD, EF, G, but if nearer C. mendax, it will only have 3 chromosomes (AB, CD, GEF).  Palearctic C. mendax is more polymorphic than C. pseudomendax.
Arm A: Groups 15-19 can be recognised near the centromere.
Arm B: Groups near the centromere as in C. montuosus, etc.  Medial inversion in C. mendax.
Arm C: Polymorphic in Palearctc populations of both C. mendax and C. pseudomendax, but nearer the distal end in C. pseudomendax.
Arm D: Polymorphic for a simple inversion of distal region in C. mendax.
Arm E1 of C. mendax is identical to that of C. montuosus and differs from C. pseudomendax by an inversion that includes band group 9.
Arm E2 of C. mendax is an inversion of about the middle third of the arm.
Arm F should have a puff (called a BR by Wülker) about a third to half way from centromere.
Arm G will be short with a large nucleolus near the presumed centromeric end (end attached to arm E if only three chromosomes) and a large BR near the other end.

FoundCalifornia - Dana Meadows (37.89°N, 119.26°W), Yosimite Ntl. Pk., Tuolumne Co. (Grodhaus & Ferrington 1989); Yosemite National Park (Ryser et al. 1985).

The larva is given by Ryser et al. (1985).  Grodhaus & Ferrington (1989) give notes on the adult of North American specimens.

See also C. (Lobo.) austini, C. (Lobo.) dorsalis, C. (Lobo.) ?nr. austini, C. (Lobo.) storai, C. (Lobo.) montuosus and C. (Lobo.) species 4v.

[ Return to Index| Go to References ]

Modified: 13 December 2019
Access: Unrestricted
Copyright © 2000-2019, Jon Martin.