Macrostemum nigrum

França, Diogo, Paprocki, Henrique & Calor, Adolfo R., 2013, The genus Macrostemum Kolenati 1859 (Trichoptera: Hydropsychidae) in the Neotropical Region: Description of two new species, taxonomic notes, distributional records and key to males, Zootaxa 3716 (3), pp. 301-335 : 305-307

Macrostemum nigrum França, Paprocki & Calor, new species

Figs. 2 A–E

The new species can be diagnosed from its congeners by the presence of a protuberant wart on each lobe of segment X and one acuminate process on the anterior margin of the phallus, near the phallobase. Moreover, the phallotremal sclerite (ventral view) is similar that of Macrostemum hyalinum , but the lateral extensions of the sclerite are longer than those in M. hyalinum . Additionally, the phallus is acuminate to the apex in the new species, while in M. hyalinum the apex of the phallus is truncate. The important diagnostic character that separates this species from all known Neotropical species is that the anterior wings are entirely black.

Description. Adults in alcohol. Forewing mean length 9.3 mm (8.62–9.96 mm, n=11). Head black, with medial carina. Compound eyes black. Scapes black, with brown setae. Maxillary palps brown, with brown and yellow setae. Prothorax black. Meso- and metathorax black. Legs brownish-yellow. Tibial spur formula 2,4,4. Forewings entirely dark, without light spots, each with discoidal cell present, radial sector normal ( Fig. 2 A).

Male genitalia. Abdominal segment IX, as viewed laterally, with anterior and posterior margins sinuous; posterior margin deeply notched, covered by setae ( Fig. 2 B); dorsally with posterior margin bearing medial acuminate keel and long setae covering right and left sides ( Fig. 2 E). Segment X, in dorsal view, bilobed, each lobe apically rounded and with subapical wart ( Fig. 2 E); in lateral view, apex truncate, with clusters of small setae on each ventrolateral margin from near base to subapical wart ( Fig. 2 B). Inferior appendages uniformly wide and covered uniformly by small setae; each with basal segment approximately three times length of apical segment and with cluster of medium setae at dorsal apex of basal segment; apical segment rounded at apex ( Fig. 2 B). Phallus acutely bent at base; apex acuminate in lateral view ( Fig. 2 C); phallotremal sclerite without dorsal process; anterior margin, as in ventral view, broadly concave and posterior margin bearing pair of rounded prominences ( Fig. 2 D); phallotrema rounded, concave, apically positioned on posterior surface of phallus.

Holotype male: BRAZIL: Bahia: Wenceslau Guimarães, Estação Ecológica Estadual Wenceslau Guimarães, Riacho Serra Grande, cachoeira em cima, 13º35’34.3’’S, 39º42’51.8’’W, 482m, 10.x.2010, luz/bandeja, A. Calor leg., 1 male (alcohol; MZSP).

Paratypes: same data as holotype, 1 male (alcohol; UFBA); Camacan, Reserva Particular do Patrimônio Natural Serra Bonita, riacho 1, trilha nova, 15º23’35.4’’S, 39º33’50.1’’W, 773m, 1.iv.2011, luz/bandeja, D. França, F. B. Quinteiro, H. Barreto leg., 1 female (alcohol; MZSP); same data except Córrego Chuchuzeiro, 15º23’26.4’’S, 39º33’52.2’’W, 777m, ii.2009, Malaise 3, A. Calor leg., 1 female (alcohol; UFBA); same data except iii.2009, 2 females (alcohol; UFBA); same data except iv.2009, 1 female (alcohol; UFBA); same data except v.2009, 1 female (alcohol; UFBA); same data except iii.2009, Malaise 2, 2 females (alcohol; UFBA); same data except 2o riacho, 3.xi.2009, luz/lençol, F. B. Quinteiro leg., 1 female (alcohol; UFBA).

Etymology. The specific epithet, nigrum , from Latin, means black and it alludes to the color of the forewings, which are completely black.

Distribution. Brazil (BA).

Figures

FIGURE 2. Macrostemum nigrum, new species. A, right fore- and hind wings, dorsal view; B – E, male genitalia: B, left lateral view; C, phallus, left lateral view; D, apex of phallus, ventral view; E, terga IX and X, dorsal view.