Indosialis bannaensis Liu, Yang

Bowles, David E. & Contreras-Ramos, Atilano, 2016, First record of the family Sialidae (Megaloptera) from Thailand and description of the female and putative larva of Indosialis bannaensis, Zootaxa 4114 (4), pp. 485-491 : 486-490

Indosialis bannaensis Liu, Yang , and Hayashi

(Figs. 1–11)

I. bannaensis Liu et al. 2006: 33 –35. Liu et al. 2008: 48 –51.

FIGURE 1. Indosialis bannaensis , female, lateral (photo: Robert W. Sites) FIGURES 2–3. Indosialis bannaensis , female terminalia. 2. ventral. 3. lateral. GP8 (gonapophyses 8), GX8, 9 (gonocoxite 8, 9), T7–10 (tergum 7–10), S7 (sternum7).

Description. Adult Female (Figs. 1–3): Head yellow with a few pale spots on dorsum; ocelli absent; clypeus brown, remainder of mouthparts yellow; antenna with scape and pedicel yellow, flagellum black [antennae broken in all specimens, number of flagellomeres unknown]; eyes black. Thorax yellow; legs with coxa, trochanter and femur yellow, but tibia, tarsus and tarsal claws brown. Wings dark brown; forewing length 10 mm, hindwing 9 mm; venation as in Liu et al. (2006). Abdomen brown; terminalia with seventh sternum broadly pentagonal in ventral view, covering proximal one-third of 8th gonapophysis; 8th gonocoxite divided into a pair of subtriangular lobes darkly sclerotized laterally becoming more membranous toward meson and overlapped by the 7th sternum; 8th gonapophysis diamond-shaped, heavily sclerotized and with posterior edge emarginate, bearing distinct, dark ridges that run from the posterior edges of emargination anteriorly for approximately one-half the length of the sclerite; 9th tergite wrapping ventrally and connecting with the 9th gonocoxite, and bearing a darkly sclerotized area on anterior margin; 9th gonocoxite broadly triangular, lightly sclerotized, and with a small gonostylus distally; 10th tergum small and suboval.

FIGURE 4. Indosialis bannaensis , larva, dorsal.

FIGURES 5–7. Indosialis bannaensis larva. 5. Habitus. 6. Head, dorsal. 7. Head, ventral.

Larva (Figs. 4–11): Total length: 15.4 mm (head and thorax 5.0 mm, abdomen 5.3 mm, terminal filament 5.1 mm). Head: width 2.0 mm, yellow to reddish brown and with irregularly spaced, small light yellow spots dorsally; antenna pale yellow. Mouthparts: mandibles symmetrical and darkly sclerotized apically and along the leading edge of the teeth, bearing two subapical teeth of which the posterior tooth is small and approximately one-half the height of the anterior tooth; remaining mouthparts orange to reddish-brown; frons broadly triangular; mentum and submentum fused, with margins rounded; submentum bearing prominent setae laterally on posterior one-half; a small oval sclerite present on posterior margin. Thorax: pronotum orange to reddish-brown and with dark brown saddles laterally and distinct yellowish reticulated pattern and spots; mesonotum somewhat cordate in shape and metanotum broadly oval, both orange to reddish brown and with distinct reticulated pattern of yellowish marks and spots; legs pale yellow and bearing long dense setae; tarsal claws reddish brown. Abdomen: dark purplish or blackish-brown dorsally and pale purplish brown ventrally; with paired, pale, comma-shaped marks on dorsum of each segment; 7 pairs of pale brown lateral abdominal gills present with pale yellow intersegmental joints; terminal filament pale yellow and subequal in length to abdomen.

FIGURES 8–11. Indosialis bannaensis larval head and thorax. 8. Head and thorax, dorsal, 9. Left mandible, dorsal. 10. Head, ventral. 11. Ligula, mentum and submentum, ventral.

Material examined. THAILAND: Kalasin Province, Phu Pan Nat. Pk., 5.vi.1998, L-152, Sites, Simpson, Vitheepradit, slow stream w/ leaf pack, 5 larvae [UMC]. Loei Province, Phu Hin Ron Kla Nat. Park, Huai Man Daeng Noi @ trail, 16o 57’ N 101o 03’ E, 1600 m, 22.iv.2002, 2 larvae [ ISU]; same, but 10.iv.2003, 2 larvae [1 ISU, 1 UNAM]; same, but 22.v.2002, 4 larvae [ ISU]; same, but 21.x.2002, 2 larvae [ ISU]; same, but 17.iii.2003, 1 larva [ UNAM]; same, but 15.xi.2002, 1 larva [ ISU]. Phitsanulok Province, Phu Hin Ron Kla Nat. Park, Man Daeng Noi, 16o 57 N’ 101o 03’ E, 1600 m, 5.v–4.vi.03, malaise trap, 1 male, 1 female [ ISU]; same, but 4–6.vii.2003, malaise trap, 2 females [ ISU]; same, but Thung Salaeng Luang, 12.v.2004, Vitheepradit & Prommi, pan light trap, 1 female [UMC].

Diagnosis. Female: The adult female has striking yellow-orange body coloration with smoky-black wings. Terminalia are most readily distinguished by the heavily sclerotized, diamond-shaped 8th gonapophysis with an emarginated posterior edge and the 8th gonocoxite divided into a pair of partially sclerotized subtriangular lobes. The body is strongly setose. Larva: One large and one small subapical mandibular teeth, yellow-orange body coloration with weak maculation, and the configuration of the fused mentum and submentum that bears a small oval sclerite on the posterior margin appear to be strong diagnostic characteristics for this genus. Pupa: Unknown.

Distribution. The specimens of I. bannaensis we examined were all from Loei, Phitsanulok, and Kalasin provinces of northern Thailand (Fig. 12). This species is also known from China and Vietnam ( Liu et al. 2006, 2008). Xingyue Liu (personal communication) indicated to us that he has examined specimens from Laos, and Chiang Mai and Nakhon-Ratchasima provinces in Thailand. These specimens have not been examined by us. Collectively, this information indicates that I. bannaensis is widely distributed in southeastern Asia. Larvae were collected from slow-flowing, sluggish streams. Nothing is known about this species biology.

FIGURE 12. The known distribution of Indosialis bannaensis in Thailand. The records from Chiang Mai and Nakhon- Ratchasima Provinces are from Xingyue Liu (personal communication).