Machairocentron amahuaca, Vilarino & Salles & Bispo, 2023

Vilarino, Albane, Salles, Frederico F. & Bispo, Pitágoras C., 2023, Xiphocentronidae (Trichoptera: Psychomyioidea) from the Andean foothills: first species of Machairocentron and Xiphocentron described in the Peruvian Amazon, European Journal of Taxonomy 860, pp. 62-80 : 65-67

Machairocentron amahuaca sp. nov.

urn:lsid:zoobank.org:act:4241D080-8E08-4428-8F3D-8ECA3877F54C

Figs 1 , 2A , 3A , 4

Machairocentron morphotype C Vilarino & Holzenthal, 2020: 31, fig. 18.

Diagnosis

Machairocentron amahuaca sp. nov. is similar to Machairocentron echinatum ( Flint, 1981) by the inferior appendage having a very elongated apical region, not enlarged apically, and having a single row of setae. It can be distinguished by: a) the mesal projection of the inferior appendage has shorter spines ( Fig. 4B ) and b) the ventral margin of the mesal projection forms a sharp right angle in lateral view ( Fig. 4A ), whereas it is rounded in other species.

Etymology

Named after the Amahuaca, an indigenous people whose language belongs to the Pano linguistic family. The name of the Amahuaca or “ amin waka ” has been translated as “children of the capybara”, an animal that is said to be able to “sing” in the native language of this people.

Material examined

Holotype PERU • ♂; 19 rd km W of Cusco, Quincemil, Rio Araza tributary; 13°20′10.0″ S, 70°50′57.00″ W; elev. 874 m; 23–31 Aug. 2012; R.R. Cavichioli, J.A. Rafael, A.P.M. Santos and D.M. Takiya leg.; Malaise trap; MUSM-ENT-0320559 .

Paratypes

PERU • 2 ♂♂; same collection data as for holotype; MUSM-ENT-0320560–0320561 • 2 ♂♂; same collection data as for holotype; DZRJ 8650–8651 .

Description of male

BODY ( Figs 2A , 3A ). Forewing length 3.8– 2.9 mm (n =5). Color overall dark brown with pale legs (in alcohol) ( Fig. 2A ). Maxillary palp segment length formula (I =II =III) <IV<V. Tibial spur formula 2:4:3; spurs unmodified. Venation: forewing forks II and IV present; fork II sessile at discoidal cell; discoidal cell about as long as thyridial cell. Hindwing forks II and V present. Sternum V with mammiliform reticulated projection ( Fig. 3A ).

GENITALIA ( Fig. 4 ). Tergum IX, in lateral view, narrow ( Fig. 4A ); in dorsal view, anterior margin with deep, wide concave incision, U-shaped; posterior margin tapered, divided apicomesally by narrow incision about ¼ its length; apex of tergite rounded lobe ( Fig. 4B ). Sternum IX, in lateral view, about 1.5× as long as high; anterior apodeme short, narrow, curved ventrad; apex deltoid ( Fig. 4A ); in ventral view, anterior margin strongly concave; posterior margin widely concave with very small mesal lobe ( Fig. 4C ). Paraproct, in lateral view, oblong, apex rounded ( Fig. 4A ); in dorsal view, each side unfused, with two pairs of setae at mid length ( Fig. 4B ); wide basally, tapering apically; divided apicomesally, with numerous sensillae on apex ( Fig. 4B ). Preanal appendage about 3.5× as long as tergum IX, densely setose; in lateral view, wide, straight on basal ⅓, slightly curved ventrad on apical ⅓, tapering apically; in dorsal view, about same width throughout length, apex curved mesad ( Fig. 4B ). Inferior appendage longer than preanal appendage; bi-segmented, with dorsal and ventral incision between them ( Fig. 4A– B ). Coxopodite shorter than harpago, with long setae ventrally ( Fig. 4A ). Harpago basal region short, sclerotized; in lateral view, narrow and oblong dorsally, wide ventrally, posteroventral margin forming sharp right angle; apical region slender, digitate, more than 4× length of basal region, bearing row of setae on mesal margin from base to apex ( Fig. 4A ); in ventral view, with lateral and mesal projections; lateral projection rounded, covered with small spines, with anterior margin straight and lateral margin crenulate; mesal projection oblong, mesal margin forming narrow flap, which circumscribes spiny concavity, apex rounded, densely covered with small spines ( Fig. 4C ). Phallus tubular, very long and slender, reaching segment V; basally conical, weakly sclerotized; in dorsal view, apex slightly enlarged, with mesal incision ( Fig. 4D ).

Remarks

The new species is described from the South Brazilian dominion, Yungas Province, and is most similar to M. echinatum , known from the Pacific dominion. This group of species is particularly recognizable by the deep concavities on the anterior and posterior margins of tergum IX. Machairocentron amahuaca sp. nov. corresponds to the “morphotype C” of Vilarino & Holzenthal (2020), defined on one damage specimen. Thus, more specimens were analyzed, confirming the consistency of the characters and the distinctiveness of the species.

Figures

Fig. 1. Distribution of species of Xiphocentronidae Ross, 1949 in Western South America. Species of Machairocentron Schmid, 1982 are indicated in white boxes, those of Xiphocentron Brauer, 1870 in black circles and those of Caenocentron Schmid, 1982 in white circles. Tropical rainforests are shown in green.

Fig. 2. Xiphocentronidae spp., adult ♂♂, habitus. A. Machairocentron amahuaca sp. nov., paratype (MUSM). B. Xiphocentron harakbut sp. nov., holotype (MUSM-ENT-03205564). Scale bars: 1 mm.

Fig. 3. Abdominal sternum V, ventral, 100 × magnification. A. Machairocentron amahuaca sp. nov. (MUSM). B. Xiphocentron harakbut sp. nov. (MUSM).

Fig. 4. Machairocentron amahuaca sp. nov., holotype, male genitalia (MUSM-ENT-0320559). A. Lateral view, with detail of paraproct. B. Dorsal view. C. Ventral view. D. Phallus, dorsal view.