Macrostemum araca, Pes & Desidério & Barcelos-Silva & Hamada, 2019

Pes, Ana M., Desidério, Gleison R., Barcelos-Silva, Patrik & Hamada, Neusa, 2019, A new species of Macrostemum Kolenati, 1859 from Brazilian Amazon and the immature stages of M. brasiliense (Fischer, 1970) (Trichoptera: Hydropsychidae), European Journal of Taxonomy 534, pp. 1-20 : 4-9

Macrostemum araca sp. nov.

urn:lsid:zoobank.org:act:054F8F36-D216-4B3C-922E-EAA97C032676

Figs 1–5

Diagnosis

Macrostemum araca sp. nov. male is similar to M. braueri and M. surinamense males by having phallus apex with long posterolateral and acuminate prominence, but it can be distinguished from these species by the shape and number of setae on tergite IX with 20 long dorsal setae and 9 lateral setae, while M. braueri has 7 long dorsal setae and 7 lateral setae and M. surinamense has 15 long dorsal setae and 8 lateral setae. Additionally, the color pattern of forewing in the new species is yellow with 2 darkbrown vertical bands on the distal half, the apical ⅓ is dark brown with an elongated median hyaline spot, while in M. braueri the forewing is mostly hyaline, each with one dark band bordering apical area and delimiting one boot-shaped hyaline area, and in M. surinamense the forewing is dark-brown with only two small hyaline bands in apical area.

The female of Macrostemum araca sp. nov. can be recognized by the sternum VIII divided almost completely along the midline into two oval plates and tergum IX with a row of long setae on the posterior margin dorsally.

Etymology

The specific epithet is a noun in apposition that refers to the Serra do Aracá mountain range, which is the type-locality of the new species.

Material examined

Holotype

BRAZIL: • ♂; Amazonas, Barcelos, Parque Estadual Serra do Aracá, Igarapé da Cobra no Acampamento (# B 01); 00°52′24.78″ N, 63°27′18.97″ W; alt. 136 m; 30 Jul.–2 Aug. 2009; A.P.M. Santos, J.O. Silva, J.L. Nessimian, N. Ferreira Jr., U.G. Neiss and F.F. Salles leg.; INPA.

Paratypes

BRAZIL: • 1 ♂, 10 ♀♀; same data as for holotype; 25 Jul. 2009; A.P.M. Santos leg.; INPA • 5 ♂♂, 1 ♀; same data as for holotype; 27 Jul.– 2 Aug. 2009; INPA • 4 ♂♂, 4 ♀♀; same data as for holotype; 4– 5 Aug. 2009; INPA • 1 ♂, 2 ♀♀; same data as for holotype; Igarapé do Jabuti (#B07); 00°52′47.78″ N, 63°28′27.05″ W; alt. 125 m; 27 Jul. – 4 Aug. 2009; A.P.M. Santos, J.O. Silva, J.L. Nessimian, N. Ferreira Jr., U.G. Neiss and F.F. Salles leg.; INPA • 2 ♂♂, 1 ♀; same data as for holotype; Igarapé da Cobra (#B08); 00°52′34.21″ N, 63°27′03.60″ W; alt. 157 m; 2–5 Aug. 2009; A.P.M. Santos, J.O. Silva, J.L. Nessimian, N. Ferreira Jr., U.G. Neiss and F.F. Salles leg.; INPA • 1 ♂; same data as for holotype; Comunidade Serrinha , Rio Aracá; 00°25′25.8″ N, 63°23′47.0″ W; alt. 69 m; 28 Jul.–6 Aug. 2009; N. Hamada, A.M. Pes, R.L.F. Keppler, C.A.S. Azevedo and C. Monteiro leg.; INPA • 1 ♀; Barcelos , [neighboring the] Serra do Aracá; 00º52′24″ N, 63º27′19″ W; alt. 149 m; Jul.–Aug. 2007; A. Filho leg.; INPA .

Description

Adult male ( Figs 1 A–G, 2A–B)

Length of forewing: 10.91–12.69 mm (mean = 10.42 mm, SD = 0.59, n = 9).

General color dark-brown and golden-yellow (in alcohol) ( Fig. 1 A–F).Antennae basal ⅓ (approximately) dark-brown, apical region yellow; scape 2 × longer than wide, with base slightly enlarged; pedicel short and broad. Head and setae dark-brown with some dark setae and anterior setal wart pale-yellow, covered with yellow setae, posterior setal wart brown, covered with brown setae, palps and haustellum paleyellow ( Fig. 1 B–C). Thorax, pronotum yellow covered with pale-yellow setae, meso- and metanotum dark-brown covered with brown setae; foreleg tibia and tarsus brown, mid and hind legs coxae and femora light-brown to yellow. Tibial spur formula 2,4,4. Midleg tarsus flattened. Forewing completely golden-yellow in basal region, with basal half without bands or spots, distal half with two vertical brown bands, the apical ⅓ is golden-brown with an elongated hyaline spot between veins R5 – M1 (may be open in the anterior region, Figs 1E , 2A ) with light spots above and below (variable from pale-yellow to light-brown until almost imperceptible), entire wing covered with fine setae, light-brown (in alcohol) ( Fig. 1 D–E); veins Sc and R1 fused near apex, forks I–V present, forks I and IV petiolate; discoidal cell small, median cell moderately in size, thyridial cell very long. Nygma and thyridium present. Hindwing almost totally golden-yellow, only with a small dark-brown triangle medially and a dark-brown band in the apical area; anal area large, veins Sc thickened and contiguous with R1 near apex; fork II, III and V present, fork V petiolate, discoidal and median cell absent, nygma present, veins between Cu and A vein anastomosed ( Figs 1F , 2B ). Sternum V, with long anterolateral glandular processes, 1.2 × longer than sternums V and VI, with basal opening and reticulated filament ( Fig. 1G ).

MALE GENITALIA. ( Fig. 3 A–I). Segment IX, in lateral view ( Fig. 3A ), with anterolateral margin slightly sclerotized and sinuous, delimited by 20 long dorsal setae and 9 scattered setae at ventral half, anterior margin almost straight; in dorsal view ( Fig. 3B ), posterior margin with triangular median keel, two lateral lobes with cluster of long setae. Segment X in lateral view ( Fig. 3A ) subtriangular, apex rounded, with subdorsal cluster of small setae near midlength, apex with smalls setae; in dorsal view ( Fig. 3B ) bilobed, each lobe with thick and short setae, mesal incision wide, forming deep, wide V-shape, reaching half-length of segment X. Inferior appendages, in lateral view ( Fig. 3A ), two-segmented, basal segment long, apical segment short, about ⅓ of the total length, apex rounded and slightly clavate, covered uniformly by long (external) and short (internal) setae; in ventral view ( Fig. 3C ) covered uniformly by long (external) and short (internal) setae. Phallus tubular, with apex dilated, forming long acuminate posterolateral prominence ( Fig. 3 D–I); in ventral view ( Fig. 3 H–I) phallotremal sclerite in shape that resembles a mushroom with 2 small apical lobes, phallotrema arrow-shaped; in dorsal view ( Fig. 3 F–G) opening of the annular phallotrema dorsally positioned.

Adult female

Length of forewing: 9.26 – 11.46 mm (mean = 10.42 mm, SD = 0.68, n = 10).

General color pattern, tibial formula, and glandular process of sternite V similar to male, differing only in the posterior setal wart, which is smaller, more triangular and not so prominent. Venation of the fore wing and hindwing similar to that of male, but the anal area of the posterior wing is about 1 ∕ 5 narrower than the wing of the male.

FEMALE GENITALIA. ( Fig. 4 A–D). Sternum VIII divided almost completely along the midline into two plates, each oval-shaped, covered with setae across the surface ( Fig. 4A, C ). Tergum IX anterior region with reticulated cuticle, similar to an irregular honeycomb, each cell with 3 to 4 short setae; in lateral view, apex with small setae; in dorsal view ( Fig. 4B ), posterior margin with a row of long setae. Tergum X small and narrow, almost entirely covered by tergum IX ( Fig. 4A, C ). Sternum X ending with 2 pairs of distinct papillae; a pair of biarticulated cerci positioned between the papillae in ventral and lateral views ( Fig. 4A, C ). Internal vaginal apparatus complex, with posterior sclerite triangular, anterior sclerite annular, wider in the median region, with two lateral projections, lateral valve long and narrow, rod-shaped ( Fig. 4D ).

Immature stages

Unknown.

Taxonomic remarks

Female genitalia of the Neotropical Macrostemum species have not been described or illustrated, so we cannot compare this structure with other species from the region. Some species from the Oriental Region have female genitalia illustrated and described ( Hoang et al. 2005). The oval-shaped ventral plate of sternum VIII is somewhat similar to that of M. floridum Navás, 1929 , but in M. araca sp. nov. it is broader at the base, and the ventral and dorsal papillae are more dilated.

Bionomics

This species was collected in the Rio Aracá (a large river, with 200–250 m of the width) ( Fig. 5E ) and in some of its small tributaries (with 1–5 m of the width), all with black water, in a forested area ( Fig. 5 C– D) located at the base of the Serra do Aracá, in the Brazilian Amazon ( Fig. 5A ).

Distribution

Brazil (Amazonas).

Figures

Fig. 1. Macrostemum araca sp. nov., adult male. A. Dorsal habitus. B–C. Head, dorsal and frontal views. D. Forewing (holotype). E. Forewing, variation in the apical area (paratype). F. Hindwing (holotype). G. Process of sternite V. Scale bars: A, D–F = 2 mm; B–C = 0.5 mm.

Fig. 2. Macrostemum araca sp. nov., adult male. A. Venation of the forewing (holotype). B. Venation of the hindwing (holotype). Scale bar = 2 mm.

Fig. 3. Macrostemum araca sp. nov., male genitalia. A. Lateral view. B. Dorsal view. C. Ventral view. D–E. Phallus, lateral view. F–G. Phallus, dorsal view. H–I. Phallus, ventral view. Scale bars: A–D = 0.2 mm; E–I = 0.1 mm.

Fig. 4. Macrostemum araca sp. nov., female genitalia. A. Lateral view. B. Dorsal view. C. Ventral view. D. Vaginal apparatus. Scale bars: A–C = 0.2 mm; D = 0.1 mm.

Fig. 5. Collection sites of Macrostemum araca sp. nov. and Macrostemum brasiliense (Fischer, 1970) and general views of some of the sampled streams and rivers. A. A map showing the collection sites of M. araca sp. nov. and M. brasiliense in the Amazon and Atlantic Forest, respectively. B. Córrego (stream) Venerando, São Paulo, collection site of M. brasiliense. – C–E. collection sites of M. araca sp. nov. C. Igarapé da (stream) Cobra, Amazonas. D. Igarapé (stream) do Jabuti, Amazonas. E. Rio (river) Aracá, Amazonas.