Anisocentropus diana Malicky & Chantaramongkol 1994

Poepetch, Sakol, Prommi, Taeng-On & Laudee, Pongsak, 2021, Description of the final instar larva of Anisocentropus diana Malicky & Chantaramongkol 1994 (Trichoptera: Calamoceratidae) in Thailand, Zootaxa 5072 (2), pp. 182-190 : 183-188

Anisocentropus diana Malicky & Chantaramongkol 1994

Anisocentropus (Anisokantropus) diana Malicky & Chantaramongkol 1994 (in Malicky 1994, 63, 71, 72, 74) male, Thailand, Malaysia; Malicky 2010, 332, male, Peninsular Malaysia, Sumatra, Thailand; Oláh & Johanson 2010, 56, Malaysia (Peninsular).

Anisocentropus diana: Nutakwang et al. 2007 , 258, Thailand; Malicky 2007, 178, Indonesia (Sumatra); Bunlue et al. 2012, 21, Thailand.

Last instar larva. Sclerotized larval head, pronotum, legs, and anal claws dark reddish brown; membranous parts of mesonotum, metanotum, and abdominal segments light reddish brown ( Figs 3C–3D ). Length 13–15 mm (n = 6).

Head ( Figs 1A , 4A, 4B ). Width 0.95–1.05 mm (n = 6), nearly circular in dorsal view, without any color patterns or dots; labrum with 18 setae in transverse row across middle; frontoclypeal apotome approximately 2/3 as long as head capsule, ten pairs of primary setae; ventral apotome large, subequal to length of ventral ecdysial line.

Thorax ( Figs 1B–1G , 4C–4E ). Strongly depressed; pronotum reddish brown with black posterior edge especially in middle, anterolateral corners extending to prominent blunt apices, each side with twelve long setae on anterior edge, two long subanterior setae, and six long lateral setae. Mesonotum with pair of large, trapezoidal, light reddish brown sclerites, each with short and diagonal anteromesal groove directed posterolaterad, one anteromedial seta (sa 1), three posteromedial setae (sa 2), and six lateral setae (sa 3). Metanotum membranous with one pair of anteromedial setae (sa 1), three pairs of posteromedial setae (sa 2), and six pairs of lateral setae on pair of small reddishbrown, anterolateral sclerites (sa 3). Foretrochantins long, curved upward, with serrate edges. Pleura of mesonotum triangular, each with distinct pleural suture; pleura of metanotum triangular. Forelegs shortest; each with coxa short, trapezoidal; trochanter oblong, 0.9 times as long as coxa; femur oblong, 1.6 times as long as coxa; tibia rectangular, 1.4 times as long as coxa; tarsus rectangular, 0.5 times as long as coxa; tarsal claw with seta on apex of stout basal process. Midlegs similar to forelegs; each with coxa trapezoid; trochanter stout, rectangular, 0.6 times as long as coxa; femur slender, rectangular, 0.9 times as long as coxa; tibia oblong, 1.3 times as long as coxa; tarsus rectangular, 0.6 times as long as coxa, tarsal claw with stout basal seta. Hind legs slender, very long, about 1.5 times as long as midlegs; each with coxa oblong, rectangular; trochanter slender, with apical black mark posteriorly, 0.6 times as long as coxa; femur slender, about as long as coxa; tibia slender, with apparent subdivision at midlength, 1.8 times as long as coxa; tarsus slender, 0.6 times as long as coxa; tarsal claw with stout basal seta.

Abdomen ( Figs 2A–2E , 5A–5D ). Strongly depressed, membranous, light reddish brown to yellowish brown; with branched gills on dorsal, lateral, and ventral sides of segments II–VIII as in Table 1 . Dorsal spacing hump of tergum I not prominent, posterodorsally with transverse, oval plate with numerous minute spines, pair of sucker-like lateroventral spacing humps with numerous spines ventrally. Segment II approximately equal in size to segment I with pair of three-branched tracheal gills dorsally. Segments III–VII strongly dorsoventrally flattened (depressed) with long lateral fringes. Segment VIII narrower than segments III–VII, and without lateral fringes. Abdominal segment VIII with transverse, light sclerite dorsally bearing 6 long setae. Anal prolegs short, each anal hook with fine accessory hook.

Case of last instar larva ( Figs 2F , 3A, 3B ): Larval case constructed with two oval pieces of angiosperm leaves, larger piece forming dorsal plate over smaller ventral piece. Posterior end of dorsal leaf piece with hole as outlet for water.

Specimens examined. THAILAND. Songkhla Province: Hat Yai District, small stream at Prince of Songkla University, Hat Yai Campus , 700’3”N, 10030’42”E, 1.viii.2006. 25 larvae , 6 mature pupae, 2 adults.

Habitat ( Figs 6A–6D ). The substrates of the stream are dominated by boulder and cobble. Stream width is 1.8–2.0 meters with 20–25 centimeters of stream depth. Anisocentropus diana larvae were collected from a pool area where dead leaves had accumulated. Larvae were associated with leaves trapped by a boulder in the pool area. In Africa, the larvae of an Anisocentropus sp. live in streams where organic debris gets trapped by exposed roots of riparian trees ( Ogbogu 2006). Ito et al. (2012) mentioned that larvae of A. kawamurai ( East Asia) and A. pallidus (Far East Russia, Hokkaido, Honshu) occur in lakes, ponds, reservoirs, stagnant stream waters, and marshland, but larvae of A. magnificus (Nansei Islands) occur abundantly in small streams. Larvae of the North American species A. pyraloides ( Walker 1852) live in slow currents of small deciduous-forest streams; early instar larvae are in accumulations of dead leaves and later instars are on the undersides of rocks and logs ( Wiggins 1996).

Figures

FIGURE 1. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. 1A, head, dorsal. 1B, pronotum, dorsal. 1C, mesonotum, dorsal. 1D, metanotum, dorsal. 1E–1G, thoracic legs: 1E, right foreleg, posterior; 1F, right midleg, posterior; 1G, right hind leg, posterior.

FIGURE 2. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. 2A, abdominal segments I–VI, left lateral. 2B, abdominal tergum I, dorsal. 2C, abdominal sternum I, ventral. 2D–2E, abdominal segment IX and anal prolegs: 2D, dorsal; 2E, ventral. 2F, larval case, ventral.

FIGURE 3. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. 3A, case, ventral. 3B, case with larva, ventral. 3C, habitus, ventral; 3D, habitus, dorsal.

FIGURE 4. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. 4A–4B, head: 4A, dorsal; 4B, ventral. 4C, pronotum, dorsal. 4D, mesonotum, metanotum, and abdominal tergum I, dorsal. 4E, right thoracic legs, posterior.

FIGURE 5. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. 5A, abdominal segments I–V, dorsal. 5B, abdominal segments VI–VIII, dorsal. 5C, abdominal segment IX with dorsal sclerite and anal proleg, left lateral. 5D, anal prolegs, ventral.

FIGURE 6. larva of Anisocentropus diana Malicky & Chantaramongkol 1994. at Khao Kho Hong stream, Prince of Songkla University, Hat Yai Campus, Hat Yai District, Songkhla Province, Thailand. 6A, 5 meters downstream. 6B, collecting site. 6C, collecting site. 6D, 50 meters downstream.