Fig. 21

This is a distinctive and diminutive species, similar only to M. pumila. Character similarities are discussed in the diagnosis for M. pumila. Mortoniella pusilla is most readily distinguished from M. pusilla by its shorter paramere appendages. These are distinctly shorter than the dorsal phallic spine in M. pusilla. Other differences include a much longer apicolateral, seta-bearing process on tergum X, a more pronounced mesal notch of tergum X, dorsal processes of the phallotheca that are more flattened and anvil-like, and an apically rounded or short angular, as opposed to more prominent and apically acute spine on the endophallic membrane. The dorsal phallic spine in M. pusilla is also less distinctly upturned and its apical part wider, as viewed dorsally.

Adult. Length of forewing: male 2.4–2.8 mm, female 2.5–3.0 mm. Forewing with forks I, II, and III present, hind wing with fork II only. Spur formula 0:3:4. Overall color light brown. Legs light brown, apices of tarsi whitish, tibial spurs somewhat darker than legs, but not strongly contrasting in color. Antennae with apical part of basal segments whitish. Wing bar at anastamosis distinct, marked with whitish setae.

Male genitalia. Ventral process of segment VI laterally compressed, ventrally projecting, subtriangular, length greater than width at base, acute to subacute apically. Segment IX nearly evenly rounded anterolaterally, length greatest midlaterally, posterolateral margin convexly rounded, narrowing ventrally; segment deeply excised dorsomesally and ventromesally, forming lateral lobes, lobes separated dorsomesally by much less than 1/2 width of segment. Tergum X with mesal margin shallowly, concavely incised, lateral lobes only weakly developed, apices truncately rounded in dorsal view, each with single, prominent ventrolateral seta on posteriorly curved, finger-like protrusion. Inferior appendages without apicomesal projection; laterally, on each side, with short, setose, dorsallydirected lobes, apices of lobes subacute. Mesal pockets of fused inferior appendages with apical processes prominent, posteriorly curved, projecting beyond inferior appendages. Paramere appendages relatively short (shorter than dorsal phallic spine), narrow, posteriorly-directed. Dorsal phallic spine, as viewed laterally, distinctly upturned in apical 1/2, apex narrowed and acute, spine very distinctly, bulbously enlarged in middle. Phallicata short, tubular, with prominent, sclerotized, raised and flattened, anteriorly-directed dorsomesal process subtending dorsal phallic spine; ventral margin weakly sclerotized, distinctly projecting. Endophallic membrane apparently short and simple in structure, with very short, curved, bluntly rounded or subacute ventromesal sclerite; phallotremal spines absent.

Holotype male: BRAZIL: Minas Gerais: Corrego Pitanga, upstream of confl. with Rio Santo Antônio, 19°05'40"S, 042°39'54"W, 238 m, 19.x.2000, Paprocki & Ferreira — (UMSP000208515) (pinned, wings mounted, body in glycerin) (MZUSP).

Paratypes: BRAZIL: Minas Gerais: same locality and date as holotype — 22 males (alcohol) (UMSP); Parque Estadual de São Gonçalo do Rio Preto, Rio Preto, 18°07'50"S, 043°20'15"W, 791 m, 12.x.2000, Paprocki, Amarante & Salgado — 36 males, 576 females (alcohol) (UMSP, NMNH, MZUSP); Rio Mainarte, bridge on Cibrão road, 20°27'15"S, 043°24'06"W, 700 m, 18.viii.1998. Paprocki & Amarante — 1 male, 1 female (pinned) (UMSP).

Etymology. This species is named M. pusilla from a Latin word for very small or little, referring to the diminutive size of this species.