Macrostemum siemreapensis Laudee & Malicky, 2020

Laudee, Pongsak, Kong, Chamroeun & Malicky, Hans, 2020, New species of caddisflies (Trichoptera: Psychomyiidae, Hydropsychidae Leptoceridae) from Mekong tributaries, Cambodia, Zootaxa 4853 (1), pp. 133-138 : 135-136

publication ID 10.11646/zootaxa.4853.1.9

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scientific name

Macrostemum siemreapensis Laudee & Malicky

sp. nov.

Macrostemum siemreapensis Laudee & Malicky n. sp.

Figs 2 View FIGURES 2 A–2G

Type material. Holotype male ( PSUNHM). Cambodia: Siem Reap Province, Siem Reap River , 13°24’09”N, 103°52’48”E, ca. 22 m a.s.l., 6.v.2019, leg. Pongsak Laudee. GoogleMaps

Paratypes. Same data as holotype, 1 male ( PSUNHM), 1 male ( CHM) GoogleMaps .

Etymology. The species is named for the type locality, Siem Reap Province.

Description. Length of each male forewing 8.0–10.0 mm (n = 3); Head and thorax dark brown dorsally. Each antenna with scapus and pedicellus light brown, some adjacent segments of antenna dark brown, remaining antennal segments pale yellow. Coxae of forelegs brown, distal ends of tibiae and claws brownish, remaining parts of legs yellow. Abdomen brown dorsally, yellow ventrally except sternum VIII brown. Forewings dark brown with yellowish white pattern same as in M. fenestratum Albarda 1887 (e.g., Malicky 2010, page 189)

Male genitalia ( Figs 2 View FIGURES 2 A–2F). In dorsal view ( Fig. 2A View FIGURES 2 ), segment IX rectangular with rectangular incision for half of its length anteriorly; posterolateral lobes of segment IX triangular; in lateral view ( Fig. 2B View FIGURES 2 ), ventral 3/4 of segment IX oval with irregularly convex anterolateral margins and rounded posterolateral lobes, apicolateral margins with numerous setae; in ventral view ( Fig. 2C View FIGURES 2 ), segment IX dumbbell-shaped. Segment X in dorsal view ( Fig. 2A View FIGURES 2 ), long, with parallel-margined incision nearly as deep as pair of resulting trapezoidal lobes; in lateral view ( Fig. 2B View FIGURES 2 ) somewhat triangular and slightly longer than basal segments of inferior appendages. Inferior appendages tubular, long; each with basal segment tubular, about 1.2 times as long as apical segment; apical segment (harpago) tubular, with round apex; curving slightly mesad in ventral view ( Fig. 2C View FIGURES 2 ). Phallus axe-shaped, broadest basally, bulbous subapically with protruding structure apicodorsally in lateral view ( Fig. 2D View FIGURES 2 ); bulbous subapical part of phallus with knot-like apex in ventral view ( Fig. 2E View FIGURES 2 ) and with looped structure in dorsal view ( Fig. 2F View FIGURES 2 ).

Diagnosis. The new species is very similar to M. fenestratum and M. dion Malicky and Chantaramongkol 1998 (in Malicky 1998), all three of which have forewings dark brown with a pale yellowish pattern. However, the dorsal apex of the phallus of the new species has no curved hooklet but instead a knot-like protruding structure in ventral view and a looped structure in dorsal view. Macrostemum seba Malicky & Prommi 2009 (in Malicky 2009) is also very similar to the new species, but the phallus of that species has no protruding structure.


Charleston Museum

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