Simulium

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

Simulium nr. sheilae 3

(Figs. 7I, 9I, 11I)

This cytoform is morphologically described based on two pupae and three larvae from site 27.

Diagnosis: The larva can be distinguished from that of other cytoforms by the combination of faint head spots, greenish transverse bands on abdominal segments I–IV, and postgenal cleft about 1.5–2.3 x as long as the postgenal bridge. The pupa is characterized by having terminal hooks with smooth margins and the gill stalk of the dorsal triplet as thick as that of the middle triplet.

This cytoform differs morphologically from S. asakoae as follows:

Female and male. Unknown. Pupa. Gill filaments ( Fig. 11 I) (1 + 2) + (1 + 2) + 2; stalk of dorsal triplet as thick as that of middle triplet. Larva. Abdominal segments I–IV each with greenish transverse band.

Chromosomes. We analyzed the chromosomes of 8 larvae from a single population (site 27). The chromosomes stained faintly and were of poor quality; photographic maps of the chromosomes, therefore, could not be made, and the cytoform remains poorly characterized. This cytoform was characterized by a complex inversion in IIIL (IIIL-complex 7). The centromere regions were not expanded. Floating inversions included IIS-9 (Fig. 4A), IIL-7 (Fig. 5A; possibly shared with S. doisaketense n. sp.).

Bionomics. The larvae and pupae of this cytoform were attached to fallen leaves in a stream 5.5–6.0 m wide at an altitude of 300 m in northern Thailand ( Table 3 ). The streambed was composed mostly of pebbles and gravel, rarely boulders.

Figures

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.