Simulium asakoae Takaoka and Davies 1995

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 : 57

Simulium asakoae Takaoka and Davies 1995

This species was described from West Malaysia ( Takaoka and Davies 1995). Takaoka and Saito (1996) noted that the male was reported as S. sp. C from Thailand by Takaoka and Suzuki (1984). The present larval specimens from Khao Yai National Park differ from Malaysian specimens in the type of setae on the abdomen and the shape of the postgenal cleft ( Fig. 4 A). The arrangement of gill filaments most closely resembles that of S. sheilae . However, adults of S. asakoae are distinguished from those of S. sheilae by the mostly white hind tibia and basitarsus, and larvae are recognized by the sparse, minute, dark, delicate, unbranched (rarely two­ or three­branched) abdominal setae ( Fig. 2 F).

The chromosomes of this species were described by Kuvangkadilok et al. (2003). A total of 67 larvae of S. asakoae were analyzed for major landmarks. The centromere regions are not notably expanded. The IIS arm has the bulge near the ring of Balbiani, which is subterminal ( Figure 1 G).

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 4. Photographs of postgenal clefts of Simulium species in subgenus Gomphostilbia. A, Simulium asakoae. B, S. gombakense. C, S. sheilae. D, S. dentistylum. E, S. sp. nr. sheilae. F, S. sp. A.