Myrsidea flavida ( Piaget, 1880 )

Schneider, Marek, Kolencik, Stanislav, Literak, Ivan & Sychra, Oldrich, 2025, Redescriptions of three species in the louse genus Myrsidea (Insecta: Phthiraptera: Amblycera), Zootaxa 5653 (3), pp. 411-428 : 417-419

Myrsidea flavida ( Piaget, 1880)

( Figs 7–13 , 25–28 )

Menopon flavidum Piaget, 1880: 438 , pl. XLII: fig. 5.

Myrsidea flavida ( Piaget, 1880) ; Price e t al. 2003: 129.

Type host: Eurylaimus ochromalus Raffles, 1822 ( Passeriformes , Eurylaimidae )—Black-and-yellow broadbill. Type locality: Unknown.

Diagnosis

Myrsidea flavida is easily identified by its unique male genital sac sclerite—long and narrow with a poorly developed distal margin and short distal arms forming a small lateral hook ( Figs 9–13 ). Kolencik et al. (2024: 40) established the flavida morphotype-group for this species. Females are defined by the following combination of characters: metanotum slightly enlarged; tergite I enlarged with a deep mediocentral convexity; tergites II–IV modified by enlarged tergite I; abdominal segments I–III and VI–VIII with well-defined median gap on each row of tergal setae; segments IV–V with a continuous row of tergal setae ( Fig. 7 ).

Descriptions

Female (n = 2). As in Figs 7 , 27 . Hypopharyngeal sclerites fully developed ( Fig. 27 ). Length of dhs 10, 0.03– 0.04; dhs 11, 0.10–0.11; ratio dhs 10/11, 0.25–0.36. Ls5 0.06 long; latero-ventral fringe with 11 setae. Gula with 3–5 setae on each side. Pronotum with 6 setae on the posterior margin and 3 short spiniform setae on each lateral corner. Prosternal plate with rounded anterior margin. First tibia with 3 outer ventro-lateral and 3–4 dorso-lateral setae. Mesonotum undivided. Metanotum enlarged, with 6–9 marginal setae (the most posterolateral setae are not included); metasternal plate with 6 setae; metapleurites with 3 short strong spiniform setae. Femur III with 15–16 setae in ventral setal brush.

Tergites modified as follows: tergite I enlarged with deep mediocentral convexity; II strongly modified by enlarged tergite I, with straight mediocentral margin; III slightly modified by enlarged tergite I ( Fig. 7 ). Abdominal segments I–III and VI–VIII with well-defined median gap on each row of tergal setae; abdominal segments IV–V with a continuous row of tergal setae. Tergal setae (postspiracular setae and short associated setae on tergites II–VIII are not included): I, 5–8; II, 8–11; III, 10; IV, 14–22; V, 12–21; VI, 9–13; VII, 7–12; VIII, 3–4. Postspiracular setae very long on II, IV, VII and VIII (0.36–0.45); long on I (0.26); and short on III, V and VI (0.10–0.18). Inner posterior seta of last tergum not longer than anal fringe setae with length 0.02; length of short lateral marginal seta of last segment, 0.05–0.06. Pleural setae: I, 5–6; II, 9; III, 9–11; IV, 8–10; V, 8–9; VI, 6–7; VII, 5–6; VIII, 3. Pleurites without anterior setae; pleurites I–III with only short spine-like setae; pleurite IV with 2–3 long slender setae; V with 3–4; VI with 2; VII with 4; Pleurite VIII one with inner seta (0.05–0.07 long) and an outer seta (0.05–0.08) plus a very long median seta ( Fig. 7 ). Anterior margin of sternal plate II with a medial notch ( Fig. 8 ). Sternal setae: I, 0; II, 4 on each aster, aster setae length: s1, 0.07–0.09; s2, 0.05; s3, 0.04; s4, 0.03–0.04; with 16–18 marginal setae between asters, 6 medioanterior ( Fig. 8 ); sternite III, 20–24 setae; IV, 32–34; V, 34–36; VI, 28; VII, 13–15; VIII–IX, 8; and 9–10 setae on deeply serrated vulval margin. Sternites III–VII without medioanterior setae. Anal fringe formed by 32–36 dorsal and 30–31 ventral setae.

Dimensions: TW, 0.41–0.44; POW, 0.34–0.36; HL, 0.33; PW, 0.28–0.30; MW, 0.48–0.55; AWIV, 0.65–0.70; ANW, 0.21–0.26; TL, 1.63–1.70.

Male (n = 5). As in Figs 26, 28 . Some data from the lectotype male ( Figs 25–26 ) are in square brackets. Hypopharyngeal sclerites fully developed ( Fig. 28 ). Length of dhs 10, 0.02–0.03; dhs 11, 0.09–0.11; ratio dhs 10/11, 0.20–0.33. Ls5 0.06–0.07 long, latero-ventral fringe with 9–11 [9–10] setae. Gula with 4–5 [4–5] setae on each side. Pronotum with 6 [6] setae on posterior margin and 3 [3] short spiniform setae on each lateral corner. Prosternal plate with rounded anterior margin. First tibia with 3[3] outer ventro-lateral and 4 [4] dorso-lateral setae. Mesonotum undivided. Metanotum not enlarged, with 4–6 [4] marginal setae (the most posterolateral setae are not included); metasternal plate with 6 [6] setae; metapleurites with 3 [3] short spiniform strong setae. Femur III with 13–16 [15–17] setae in ventral setal brush.

Abdominal segments with well-defined median gap on each row of tergal setae. Tergal setae (postspiracular setae and short associated setae on tergites II–VIII are not included): I, 7–8 [10]; II, 8–9 [10]; III, 6–8 [11]; IV, 6–9 [10]; V, 6–7 [7]; VI, 4–6 [7]; VII, 4–7 [7]; VIII, 4 [4]. Postspiracular setae very long on II, IV, VII and VIII (0.42–0.54); long on I (0.14–0.19; short on III, V and VI (0.10–0.13). Length of inner posterior seta of last tergum, 0.05–0.07; short lateral marginal seta of last segment, 0.02. Pleural setae: I, 3–5 [4]; II, 5–8 [6]; III, 6–8 [7]; IV, 5–7 [6]; V, 5–6 [6]; VI, 4–6 [5]; VII, 4–5 [4]; VIII, 3 [3]. All pleurites with only short spine-like setae, and without anterior setae. Pleurites IV, 1–2 [1]; V, 1–3 [2]; VI, 1–3 [2]; VII, 2–3 [2] with slender and longer setae. Pleurite VIII with inner setae (0.05–0.07) twice as long as outer (0.02–0.04). Anterior margin of sternal plate II with a medial notch. Sternal setae: I, 0 [0]; II, 3–4 [4] in each aster, aster setae length: s1, 0.08–0.09; s2, 0.05–0.06; s3, 0.04–0.05; s4, 0.04–0.04; with 15–18 [16] marginal setae between asters, 2–6 [6] medioanterior; III, 17–20 [19]; IV, 18–24 [26]; V, 26–28 [35]; VI, 18–30 [27]; VII, 14–16 [15]; VIII, 2–4 [4]; remainder of plate, 6–7 [6]; and with 4–6 [4] setae posteriorly; sternites III–VII without medioanterior setae. With 6–8 [8] internal anal setae. Genital sac sclerite long and narrow with poorly developed distal margin that can be easily distorted; distal arms (sensu Kolencik et al. 2024) short, forming a small lateral hook ( Figs 9–13 ).

Dimensions: TW, 0.38–0.41 [0.43]; POW, 0.31–0.33 [0.33]; HL, 0.29–0.30 [0.29]; PW, 0.26–0.29 [0.29]; MW, 0.29–0.38 [0.38]; AWIV, 0.46–0.50 [0.48]; GW, 0.13–0.15 [0.10]; GL, 0.38–0.43 [0.44]; ParL, 0.08–0.09 [0.08]; GSL, 0.07–0.09 [0.08]; TL, 1.33–1.37 [1.36].

Material examined

Figures

FIGURES 7–13. Myrsidea flavida: 7, dorso-ventral views of female thorax and abdomen. 8, female metasternal plate and sternites I–II. 9–13, various views of the male genital sac sclerite.

FIGURES 25–28. Myrsidea flavida: 25, slide with lectotype. Habitus: 26, lectotype male. 27, female. 28, male.