Simulium (Simulium) tani Takaoka & Davies, 1995

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya’Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng & Pham, Xuan Da, 2015, The black flies (Diptera: Simuliidae) from Thua Thien Hue and Lam Dong Provinces, Vietnam, Zootaxa 3961 (1), pp. 1-96 : 85

Simulium (Simulium) tani Takaoka & Davies, 1995 (complex)

( Fig. 38 )

Simulium (Simulium) tani Takaoka & Davies, 1995: 137 –141 (Female, male, pupa and larva).

Specimens examined. Morphoform ‘a’: Eight females, 11 males, 10 pupae, 15 mature larvae collected from a moderately to fast flowing stream (width 1–3 m, depth 0.5–1.0 m, water temperature 17˚C, partially shaded, altitude 628 m, 16˚18’16.209” N/107˚12’48.027” E), Luoi, Thua Thien Hue Province, central Vietnam, 24-II-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau. Morphoform ‘b’: Four females, 11 males, all reared from pupae collected from a small stream (width 0.5–2.0 m, depth 5–10 cm, water temperature 22.0˚C, shaded, altitude 1,443 m, 11˚59’25.511” N/108˚22’06.350” E), moderately flowing from a natural forest, Suoi Vang (21 km from Dalat), Lac Duong District, Lam Dong Province, southern Vietnam, 22-IV-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau; 12 females, three males, five pupae and four pupal exuviae collected from a small stream (width 1–2 m, depth 10–20 cm, water temperature 15.0˚C, partially shaded, altitude 1,539 m, 12˚01’24.991” N/108˚25’30.704” E), moderately flowing in Resort Park, Langbiang, Lac Duong District, Lam Dong Province, southern Vietnam, 25-IV-2014, by H. Takaoka, M. Sofian-Azirun, Z. Ya’cob, C.D. Chen & K.W. Lau.

Distribution. Peninsular Malaysia, Thailand, Sumatra, and Vietnam.

Remarks. This species is a species-complex comprising 12 cytoforms ( Adler and Crosskey 2014). In Thailand, nine cytoforms of the S. (S.) tani (complex) are known ( Adler and Crosskey 2014). In our surveys, the S. (S.) tani (complex) is divided into two morphoforms (‘a’ and ‘b’): morphoform ‘a’ collected from central Vietnam and morphoform ‘b’ collected from southern Vietnam. Morphoform ‘a’ is similar to cytoform ‘K’ of the S. tani (complex) from Peninsular Malaysia although the length ratio of the female sensory vesicle against the third segment of the maxillary palp is different from that of the latter cytoform (i.e., 0.50–0.55 in morphoform ‘a’ vesrus 0.63 in cytoform ‘K’, which was obtained by measuring recently collected samples). Morphoform ‘b’ is characterized by lacking pupal terminal hooks, by which this form is separated from cytoform ‘K’ from Peninsular Malaysia and morphoform ‘a’ from central Vietnam. Morphoform ‘b’ is also distinguished from cytoform ‘K’ in the female by the relatively smaller size of the sensory vesicle to the third maxillary palpal segment (0.55 versus 0.63). Morphoform ‘b’ is also distinguished from morphoform ‘a’ by the short anterodorsal trichomes ( Fig. 38 I) that are subequal in length to the anterolateral trichomes ( Fig. 38 J) [cf., anterodorsal trichomes of morphoform ‘a’ are short ( Fig. 38 C)]. The pupal gills of mophoforms ‘a’ and ‘b’ are almost the same ( Fig. 38 M) but are different from that of S. (S.) xuandei sp. nov. ( Fig. 41 H).

Figures

FIGURE 38. Pupa of Simulium (Simulium) tani (complex). A – F, morphoform ‘ a’; G – M, morphoform ‘ b’. A & G, frontal trichomes; B & H, facial trichomes; C & I, anterodorsal thoracic trichomes; D & J, anterolateral thoracic trichomes; E & K, mediolateral thoracic trichomes; F & L, ventrolateral thoracic trichomes; M, gill (left side; outer view). Scale bars. 0.1 mm for M; 0.02 mm for A, B, D, E and G – L; 0.01 mm for C and F.

FIGURE 41. Pupa and mature larva of Simulium (Simulium) xuandei sp. nov. A – I, pupa; J – L, larva. A, tubercles with minute secondary projections on frons; B, frontal trichomes; C, facial trichome; D – G, thoracic trichomes (D, anterodorsal; E, anterolateral; F, mediolateral; G, ventrolateral); H, gill filaments (right side; outer view); I, terminal hooks (caudal view); J, mandible; K, hypostoma; L, head capsule with postgenal cleft (ventral view). Scale bars. 0.1 mm for H; 0.05 mm for L; 0.02 mm for A – G and I – K.