Simulium

Simulium nr. asakoae 2

(Figs. 6C, 7C, 9C, 11C)

[Simulium asakoae, Phasuk, 2006: 88 (misident. in part, Fig. 30C)]

The following morphological description is based on a single pupa and three larvae from site 30.

Diagnosis: The larva can be distinguished from other cytoforms in the S. ceylonicum group by the combination of a yellowish abdomen (except segments I–III greenish), abdominal segment V without a distinctly pigmented band, and abdominal setae unbranched. The pupa cannot be distinguished from that of others cytoforms.

This cytoform differs morphologically from S. asakoae as follows:

Female and male. Unknown. Pupa. Gill filaments (Fig 11 C) of dorsal and middle groups each of 3 filaments arising near common base, arranged (3) + (3) + 2 from dorsal to ventral; terminal hooks each with crenulated outer margin. Larva. Head spots faintly positive; abdominal segments I–III with greenish transverse bands, segments V–VIII without distinct bands.

Chromosomes. The chromosomes of seven larvae from two populations (sites 22 and 30) were analyzed. This cytoform differed from the standard map by fixed inversion IIL-9 (Fig. 5A), which was shared with S. curtatum n. sp., and a complex set of inversions in IIIL, denoted as IIIL-complex 4 (Fig. 6C) The centromere regions were condensed. No floating inversions were discovered.

Bionomics. This cytoform was found on fallen leaves in streams of moderate width (3.7–5.0 m) at altitudes of 300–700 m (Table 3). Larvae of this cytoform were collected with those of S. asakoae at site 30 and S. doisaketense n. sp. at site 22.

Cytoform Altitude (m) Stream Stream Stream Conductivity Dissolved pH Water tem-

width (m) depth (m) velocity (m/ (µs/cm) oxygen (mg/l) perature

sec) (ºC)