Conochironomus larva, ‘Mae Ping’ sp.

Cranston, Peter S., 2016, Conochironomus (Diptera: Chironomidae) in Asia: new and redescribed species and vouchering issues, Zootaxa 4109 (3), pp. 315-331 : 326

Conochironomus larva, ‘Mae Ping’ sp. ( Fig. 5 E, G).

L; THAILAND: Lamphum Prov., Mae Ping N.P., Nam Tok Koh Luang, 17°34'N 98°49’E, 6.iii.2002, L-266, TH73 (Courtney).

Head capsule length c. 380, postmentum length 147. Antenna ( Fig. 5 E) with segment lengths (base to apex): 50, 18, 19, 14, 8.5, 5; AR 0.77; Lauterborn organs alternate, large, 20–21 long; origin of basal Lauterborn organ broadens apex of segment 2 ( Fig. 5 E). Style slender, 9; blade 59 long, not extending to apex of antenna. Mandible 125, with outer tooth as dark as apical tooth; two dark inner teeth; mola has three spines, one close to base of seta subdentalis, two on inner margin. Labrum with SI setae arising from common base; SI, SII plumose; pecten epipharyngis with 4, 2, 4 blunt teeth in 3 closely approximated scales; premandible with 2 strong apical teeth but orientation precludes count of inner teeth; with very strong and long beard. Mentum ( Fig. 5 G); total width 95, with cluster of 4 median (ventromental) teeth much smaller and retracted median pair of teeth; all teeth brown. Ventromental plates 21 apart medially, single plate 132 long, anterior margin smooth.

Abdomen. Anterior parapod claws pale golden, simple, forming dense cluster. Procercus and apical setae yellow. Posterior parapod claws golden brown. Anal papillae 350, each with two obvious constrictions.

This larva is differentiated from that of C. tobaterdecimus on antennal features, i.e. the Lauterborn organs ( Fig. 5 E) being much larger (20 versus 8–9 µm) and with the basal Lauterborn organ placed subapically, the 2nd antennal segment being subequal in length to the 3rd from the lower Antennal Ratio (0.78 versus 0.9–1.0) and the blade not reaching the terminal antennal segment. The reduced size of the median pair of mental teeth may differentiate also, but variation in dorsomental teeth proportions seems high.

Figures

FIGURE 5. Conochironomus spp., immature stages. A – C. C. tobaterdecimus (Kikuchi & Sasa), pupal abdomen (anal lobe taeniae omitted): A. Dorsal view; B. Segments VII – IX, ventral; C. Posterolateral corner of VIII, ventral. D-G. Conochironomus spp., Larvae. D. Antenna, C. tobaterdecimus; E. Antenna, C. ‘ Mae Ping’ sp. indet.; F. Mentum and ventromental plate, C. tobaterdecimus; G. Mentum (part), C. ‘ Mae Ping’ sp. indet.