Simulium

Tangkawanit, Ubon, Kuvangkadilok, Chaliow, Baimai, Visut & Adler, Peter H., 2009, Morphotaxonomy of the Simulium (Simulium) tuberosum species group (Diptera: Simuliidae) in Thailand, Zootaxa 2048, pp. 31-46 : 40-41

Simulium unknown species 2

This taxon was recognized cytologically based on 8 larvae from Champa Thong waterfall in Phayao Province ( Tangkawanit et al. 2009). The larvae are morphologically similar to those of S. yuphae , but lack head spots and infuscation on the frontoclypeal apotome. The larva of S. unknown species 2 is described below, but we defer formal description and naming of this species until pupae and adults are available.

Body grayish black to grayish brown. Head capsule yellowish to light brown; head spots faint ( Fig. 2 I); ventral surface of head capsule whitish yellow except area along margins of postgenal cleft dark brown; faint negative transverse spot on each side of postgenal cleft ( Fig. 3 J). Antenna longer than stem of labral fan; length ratios of articles (proximal to distal) 1.00: 1.05: 0.76. Labral fan with 36–38 primary rays. Hypostoma with median tooth and each lateral tooth longer than others; 5 or 6 hypostomal bristles per side. Postgenal cleft deep, triangular, pointed anteriorly ( Fig. 3 J). Abdominal cuticle nearly bare; both sides of anal sclerite moderately covered with simple colorless setae. Anal sclerite X shaped with broadened anterior arms 0.8–0.9 times as long as posterior arms. Abdominal segment IX lacking ventral tubercles. Posterior circlet with 70–80 rows of hooklets and up to 14 hooklets per row.

Figures

FIGURE 2. Head capsules of mature larvae of Simulium tuberosum group from Thailand. A, S. doipuiense cytoform A. B, S. doipuiense cytoform B. C, S. manooni. D, S. rufibasis. E, S. setsukoae. F, S. tani cytoform D. G, S. weji. H, S. yuphae. I, Unknown species 2. Scale bars = 0.5 mm.

FIGURE 3. Postgenal clefts of mature larvae of Simulium tuberosum group from Thailand. A, S. doipuiense cytoform A. B, S. doipuiense cytoform B. C, S. manooni. D, S. rufibasis. E, S. setsukoae. F, S. tani cytoform F. G, S. tani cytoform G. H, S. weji. I, S. yuphae. J, Unknown species 2. Scale bars = 0.1 mm.