Simulium siamense Takaoka and Suzuki 1984

Phasuk, J., Chanpaisaeng, J., Adler, P. H. & Courtney, G. W., 2005, Chromosomal and morphological taxonomy of larvae of Simulium (Gomphostilbia) (Diptera: Simuliidae) in Thailand, Zootaxa 1052, pp. 49-60 : 54

Simulium siamense Takaoka and Suzuki 1984

Simulium siamense was described from specimens collected in Mae Hong Son, Thailand ( Takaoka and Suzuki 1984). The present specimens differ slightly from those in the original description by having minute black setae on the larval thorax. The eightfilamented gill is arranged in groups of 3 + 3 + 2 from dorsal to ventral ( Fig. 3 D). The larva can be identified by the presence of dark setae with 6–8 branches on abdominal segments V–VIII ( Fig. 2 D).

The chromosomes of this species were described by Kuvangkadilok et al. (2003). Sixteen of 52 larvae were analyzed for major landmarks. None of the centromere regions are expanded. The IIS arm has the ring of Balbiani near the subterminal bulge ( Fig. 1 E).

Figures

FIGURE 1. Idiograms of chromosome arm IIS for 12 Simulium species in subgenus Gomphostilbia from Khao Yai National Park, showing relative locations of Ce, centromere; RB, ring of Balbiani; Bu, bulge; Sh, shoestring. A, Simulium angulistylum. B, S. decuplum. C, S. dentistylum. D, S. gombakense. E, S. siamense. F, S. sp. A. G, S. asakoae. H, S. sheilae. I, S. sp. nr. sheilae. J, S. novemarticulatum. K, S. sp. B. L, S. sp. C.

FIGURE 2. Photographs of setae on abdominal cuticle of Simulium species in subgenus Gomphostilbia. A, Simulium angulistylum. B, S. decuplum. C, S. dentistylum. D, S. siamense. E, S. sp. A. F, S. asakoae. G, S. sheilae. H, S. sp. nr. sheilae. I, S. novemarticulatum. J, S. sp. B.

FIGURE 3. Photographs of gill filaments of Simulium species in subgenus Gomphostilbia. A, Simulium angulistylum. B, S. sp. A. C, S. novemarticulatum. D, S. siamense. E, S. sheilae. F, S. sp. nr. sheilae.