Mesophylax impunctatus aduncus ( Navás 1923 )

Waringer, Johann & Malicky, Hans, 2019, The larvae of Limnephilus minos Malicky 1970 and Mesophylax impunctatus aduncus (Navás 1923) (Trichoptera: Limnephilidae), including a discriminatory matrix for the Greek limnephilid larvae with multifilament gills, Zootaxa 4612 (2), pp. 187-204 : 189-190

Description of the final instar larva of

Mesophylax impunctatus aduncus ( Navás 1923)

( Figs 15–24 )

Biometry. Body length of 5th instar larva 16.1–16.2 mm, head width 1.32–1.36 mm (n = 2). All morphological characters identical to those of Limnephilus minos except as noted below.

Head. Head capsule light brown, with medium brown, conspicuous muscle attachment spots ( Fig. 15 ). Labrum medium brown ( Fig. 15 ). Ventral apotome very narrow, elongate, medium brown; postgenal suture approximately 15–17% of apotome length ( Fig. 16 va). Mandibles black, without terminal teeth, and without ridges in central concavity ( Fig. 15 , arrow).

Thorax. Pronotum ( Fig. 17 p ) yellow, with light brown muscle attachment spots. In total, 55–68 dark setae of varying lengths distributed over each pronotal half. Yellow central prosternite conspicuous, outlined like a flying bird’s silhouette: slightly pointed at anterior center, with pointed winglike lateral sections and fan-shaped, brown posterior extension ( Fig. 18 ps). Mesonotum ( Fig. 17 ms) yellow, with dark brown muscle attachment spots. Lateral and posterior margins strongly sclerotized, creating continuous black frame of mesonotum extending to anterolateral corners ( Fig. 17 ms). Anterior mesonotal setal group sa 1 each with 12–15 setae, posterior group sa 2 each with 10–13 setae, lateral group sa 3 each with 16–21 setae ( Fig. 17 ). Metanotal sclerites sa 1 yellow, transversely narrow and wide; with 8–10 setae per sclerite and additional small group of 3–4 setae lateral of each sclerite ( Fig. 17 sa 1). Yellow sclerites of sa 2 with 6–8 setae per sclerite ( Fig. 17 sa 2) and with small group of setae between them ( Fig. 17 , dotted oval). Yellow sclerites of sa 3 with dark brown muscle attachment spots, each with 16–23 setae ( Fig. 17 sa 3); with small group of setae on each side between sa 2 and sa 3. Mesosternum with 4–8 dark setae, metasternum with 15–26 dark setae ( Fig. 18 mss, mts). Legs yellowish brown, femora of 2nd and 3rd legs each with one proximodorsal seta, with additional setae on anterior and posterior faces ( Fig. 19 , dotted oval), and with 4–7 ventral-edge setae ( Fig. 19 , arrows). Proximal section of each mid- and hind trochanter with additional setae.

Abdomen. Abdominal segment I dorsal sa 1 and sa 2 confluent on each side, with 9–16 setae; sa 3 with 4–8 setae each, with very tiny brown basal sclerites ( Fig. 17 ). Abdominal sternum I on each side with 14–17 setae in sa 1, 18–24 setae in sa 2, and 5–7 setae in sa 3 ( Fig. 18 ). Dorsal gills present at most from segment II (presegmental position) to segment VI (postsegmental position). Ventral gills ranging from segment II (presegmental) to segment VII (postsegmental). Lateral gills present from segment II (postsegmental) to segment IV (pregmental). Chloride epithelia lacking. Number of posterodorsal setae on abdominal segment VIII 10–12, with 8 long and remainder short ( Fig. 21 pds); with 1–2 posterolateral setae ( Fig. 21 pls). Abdominal tergite IX yellow, with dark brown muscle attachment spots ( Fig. 21 ); posterior border with 10–12 long and several shorter setae ( Fig. 21 ). With small groups of setae on both sides of anal slit ( Fig. 22 , dotted oval).

Case. Fifth instar larval case 13.9–14.7 mm long (n = 2), straight, slightly tapering posteriorly (width at anterior opening 3.1–4.0 mm and at posterior opening 2.1–2.7 mm) ( Fig. 24 ), consisting of mixed mineral particles.

Figures

FIGURES 13–16. Mesophylax and Limnephilus spp., 5th instar larvae. Figures 13–14. Limnephilus minos Malicky 1970: 13, tip of abdomen, right lateral (ac = anal claw; ls = lateral sclerite; pds = posterodorsal setae; pls = posterolateral seta; vs = ventral sole plate); 14, larval cases, right lateral. Figures 15–16. Mesophylax impunctatus aduncus (Navás 1923): 15, head, right frontolateral (a = antenna; small white numbers = setal positions; ph = prosternal horn; arrow = right mandible without terminal teeth); 16, head, ventral (c = cardo; va = ventral apotome; small white numbers = setal positions). Scale bars: 0.5 mm.

FIGURES 17–22. Mesophylax impunctatus aduncus (Navás 1923), 5th instar larva. 17, pro-, meso-, and metanota and abdominal tergum I, dorsal (dp = dorsal protuberance on abdominal tergum I; is = intermediate setae between pair of sa2; lp = lateral protuberance on abdominal segment I; ms = mesonotum; mt = metanotum; p = pronotum; sa1–3 = setal areas 1–3, indicated by dotted ovals on abdominal tergum I); 18, pro-, meso-, metasterna and abdominal sternum I, ventral (epm = epimeron; mss = mesosternal setae; mts = metasternal setae; ph = prosternal horn; ps = prosternum; sa1–3 = setal areas 1–3); 19, left midleg femur, posterior face (dotted oval = face setae; arrows = ventral-edge setae); 20, abdominal segments I–III, right lateral (lf = lateral fringe; lps = lateral protuberance seta; dotted ovals refer to dorsal and ventral sa3); 21, abdominal terga VIII–X, dorsal (pds = posterodorsal setae on abdominal tergum VIII; pls = posterolateral seta); 22, abdominal tip, caudal (as = anal slit; dotted oval = setal group laterad of anal slit). Scale bars: 0.5 mm.

FIGURES 23–30. Mesophylax and Limnephilus spp., 5th instar larvae. Figures 23–24, Mesophylax impunctatus aduncus (Navás 1923): 23, tip of abdomen, right lateral; 24, larval case, right lateral. Figure 25, Limnephilus extricatus McLachlan 1865, abdominal tergum I, dorsal (dotted oval = intermediate setae between pair of sa2; sa1, sa2 = setal areas 1 and 2). Figure 26, Limnephilus griseus (Linnaeus 1758), abdominal segments I–III, right lateral (arrow = presegmental dorsolateral gill, consisting of three filaments). Figure 27, Limnephilus flavicornis (Fabricius 1787), right midleg femur, posterior face (dotted oval = face setae; arrows = dark ventral-edge setae). Figure 28, Limnephilus affinis Curtis 1834, left midleg femur, anterior face (dotted oval = face setae). Figure 29, L. flavicornis, pronotum, dorsal. Figure 30, Limnephilus decipiens (Kolenati 1848), head and pronotum, right lateral (plb = pleural band). Scale bars: 0.5 mm.