Simulium inthanonense Takaoka and Suzuki, 1984

Jitklang, Sanae, Kuvangkadilok, Chaliow, Baimai, Visut, Takaoka, Hiroyuki & Adler, Peter H., 2008, Cytogenetics and morphotaxonomy of the Simulium (Gomphostilbia) ceylonicum species group (Diptera: Simuliidae) in Thailand, Zootaxa 1917, pp. 1-28 : 21-22

Simulium inthanonense Takaoka and Suzuki, 1984

(Figs. 6F, 7J, 9J, 11J)

Simulium inthanonense Takaoka and Suzuki, 1984: 18 –21 (male, female, pupa, larva)

We briefly redescribe this species based on two pupae and three larvae from sites 14, 36, and 48. Morphological characters of our larvae and pupae match those in the original description by Takaoka and Suzuki (1984), with the following exceptions. The postgenal cleft is about 1.2–1.5 x as long as the postgenal bridge rather than 0.67 x in the original description. Minor differences also are found in the number of hypostomal bristles, primary rays in the labral fan, secondary lobules of the rectal papillae, and hooklet rows in the posterior circlet. In addition, the anterodorsal projection of the cocoon in our material is not as long as that illustrated in the original description ( Takaoka and Suzuki 1984). Some of our material (sites 4 and 48) is from the general area of the type locality of S. inthanonense (Doi Inthanon National Park). Until evidence to the contrary can be shown, we consider these differences to be intraspecific.

Diagnosis. This species is distinguished from other cytoforms by the combination of a short postgenal cleft and greenish transverse bands on abdominal segments I and IV in the larva and the presence of an anterodorsal projection on the pupal cocoon.

Simulium inthanonense differs morphologically from S. asakoae as follows:

Female and male. Not available in this study. Pupa. Gill filaments ( Fig. 11 J) (1 + 2) + (1 + 2) + 2; terminal hooks each with serrated outer margin; cocoon with anterodorsal projection. Larva. Postgenal cleft ( Fig. 9 J) short, ca. 1.2–1.5 x as long as postgenal bridge; abdominal segments I and IV each with greenish transverse band.

Chromosomes. The chromosomes of 22 larvae from three populations (sites 14, 36, and 48) stained faintly. The centromere regions were not expanded. The chromosomes were characterized by fixed inversions IS-5 (Fig. 2A), IIS-6 (Fig. 4A), IIL-7 (Fig. 5A), IIIS-1 (Fig. 3), and IIIL-complex 3 (Fig. 6F). One floating inversion, IIIS-3 (Fig. 3), was observed.

Bionomics: The larvae and pupae of S. inthanonense were attached to fallen leaves in cool (18.0 ºC), slow streams (0.1–0.3 m /s) at high altitudes (950-1615 m) ( Table 3 ). This species occurred with S. asakoae and S. curtatum n. sp. at site 14 and with S. curtatum n. sp. at site 48.

FIGURE 12. Morphological features of adults of Simulium curtatum n. sp. (A) female antenna (left), (B) male antenna (left), (C) 3rd segment of maxillary palp with sensory vesicle of female (right, frontolateral view), (D) female hind leg (left, inner view), (E) male hind leg (left, inner view), (F) sternite 8, anterior gonapophyses, genital fork, and spermatheca of female genitalia (ventral view), (G) anal lobe and cercus (left, ventrolateral view), (H) left gonocoxite and gonostylus (ventrolateral view), (I) ventral plate (ventral view), (J) ventral plate (end view), (K) ventral plate (lateral view), (L) paramere and hooks, (M) median sclerite (posterolateral view). Scale bars = 0.05 mm for A and B; 0.01 mm for C, G, and H; 0.1 mm for D and F; 0.02 mm for I, J, K, L, M, and N.

Figures

FIGURE 9. Postgenal clefts of larvae of 10 cytoforms of the Simulium ceylonicum species group in Thailand. (A) S. asakoae, (B) S. curtatum n. sp., (C) S. nr. asakoae 2, (D) S. nr. asakoae 3, (E) S. nr. asakoae 4, (F) S. sheilae, (G) S. trangense n. sp., (H) S. doisaketense n. sp., (I) S. nr. sheilae 3, and (J) S. inthanonense. Scale bar = 0.1 mm.

FIGURE 11. Gill filaments of 10 cytoforms of the Simulium ceylonicum species group in Thailand. (A) S. asakoae, (B) S. curtatum n. sp., (C) S. nr. asakoae 2, (D) S. nr. asakoae 3, (E) S. nr. asakoae 4, (F) S. sheilae, (G) S. trangense n. sp., (H) S. doisaketense n. sp., (I) S. nr. sheilae 3, and (J) S. inthanonense. Scale bar = 0.1 mm.