Acrocephalomyia pulchra, Alvim, Edgar & Ale-Rocha, Rosaly, 2016

Alvim, Edgar & Ale-Rocha, Rosaly, 2016, Two new species of Acrocephalomyia Ibáñez-Bernal & Hernández-Ortiz, 2012 from Brazil (Diptera: Ropalomeridae) and a key to known species, Zootaxa 4067 (1), pp. 57-64 : 58-60

Acrocephalomyia pulchra sp. nov.

( Figs. 1–5 )

Diagnosis. Face covered with white pruinescence; ocelli almost imperceptible, but present; wing uniformly black smoky; legs black except the first tarsomeres yellow; fore femur with posteroventral row with 2 spine-like bristles, ventral surface lacking setulae on basal half; mid femur with anteroventral row with 10 spine-like bristles, posteroventral row with 5 spine-like bristles and dorsally with concavity on basal third; hind femur with anteroventral row bearing 4 spine-like bristles and posteroventral row with 5 spine-like bristles; hind tibia not arched.

Description. Holotype female. Body: 14 mm; wing: 10 mm. ( Fig. 1 ) Head: Frons concave ( Fig. 3 ); predominantly brown, with posterior black triangular spot covered with silvery pruinescence, which extends from occiput and reaches anterior margin of frons on a depressed line that divides the frons in half. Ocellar tubercle absent; ocelli almost imperceptible, but present. Ocellar, postocellar and inner vertical bristles absent. Face brown covered with white pruinescence ( Fig. 5 ). Antenna brown; scape and pedicel covered with black setulae, especially on dorsal surface, first flagellomere dark brown. Palpus elongated, with rounded apex and parallel sides, brown with yellowish setulae basally. Gena ( Fig. 4 ) concolor with face, covered with white pruinescence and some black setulae, postgena with longitudinal stripe of silvery pruinescence and long and thin white setulae. Thorax: Scutum black, about two times longer than wide, with four silvery pruinescent stripes, one pair dorsocentral and one stripe on each side, extended from postpronotal lobe to scutoscutellar suture ( Fig. 2 ). Chaetotaxy: 2 notopleural, 1 postsutural supra-alar, 1 postalar, 1 intra-alar, and 1 intra-postalar. Scutellum shaped as an isosceles triangle in dorsal view; covered with short black setulae and sparse silvery pruinescence; one apical pair of bristles, inserted very close to each other. Mesopleuron with silvery pruinescent stripe extending to posterior margin of anepimeron; bristles lacking except for weak scattered setulae on anepisternum, anepimeron and katepisternum; posterior spiracle without bristles. Wing: uniformly black smoky ( Fig. 2 ). Legs: black except the first tarsomeres yellow. Fore coxa covered with silvery pruinescence; hind coxa simple, lacking lateral expansion. All femora covered with fine black setulae and sparse silvery pruinescence; fore femur with anteroventral row with 8 spine-like bristles and posteroventral row with 2 spine-like bristles, ventral surface lacking setulae on basal half; mid femur with anteroventral row with 10 spine-like bristles, posteroventral row with 5 spine-like bristles and dorsally with concavity on basal third, lacking short white setulae ventrally, posterodorsal bristles on apical third and pines on anterior surface; hind femur with anteroventral row bearing 4 spine-like bristles and posteroventral row with 5 spine-like bristles and without long black bristles ventrally and spine-like bristles on anterior surface. Fore tibia with silvery pruinescence dorsally on apical third; anterior surface with a stripe with short yellow setulae becoming denser apically and advancing to tarsomeres; mid tibia slightly arched, ventrally with dense thin and long black setulae, and 6 ventroapical spine-like bristles, posterodorsal and ventral surfaces lacking spine-like bristles or tubercles; hind tibia not arched, with thin and long black bristles, more dense ventrally and tuft of ventroapical short yellow setulae. Abdomen: Terga black with silvery pruinescence on sides of terga 1-2. All sterna covered with silvery pruinescence; with thin black and brown setulae.

Male: Unknown.

Type material. Holotype female ( CZPB) BRAZIL, labelled: Brasil, Amazonas, Coari, Rio Urucu. ROC- 36. 4C- 36. 4 436. 4 36. 436. 4. ROC- 36. 4 36. 4 Urucu. RO Buhrnheim et al col[etors].

Geographical records. Only the type locality, Brazil (Amazonas).

Etymology. From Latin pulcher = beautiful. Refers to the general aspect of the species.

Discussion. In this species the body and legs are black, contrasting with the frons, face and antennae, which are brown, and the first tarsomere of all legs, which are yellowish. It can be separated from A. zumbadoi Ibáñez- Bernal & Hernández-Ortiz by the presence of ocelli. Furthermore, the anterior surface of the fore tibia of A. pulchra sp. nov. has a stripe of short yellow setulae that become denser apically and extend to the tarsomeres; the mid tibia bears 6 ventroapical spine-like bristles; and the hind tibia bears a ventroapical tuft of short yellow setulae. In A. zumbadoi , the stripe of short yellow setulae on the anterior surface of the fore tibia is absent, the mid tibia bears 4 ventroapical spine-like bristles and the ventroapical tuft of short yellow setulae is absent from the hind tibia. Acrocephalomyia pulchra sp. nov. can be separated from A. torulosa sp. nov. by the characteristic mentioned in the discussion of A. torulosa sp. nov..

Both new species have almost imperceptible ocelli. However, in the diagnosis of the genus proposed by Ibáñez-Bernal & Hernández-Ortiz (2012), ocelli are absent in Acrocephalomyia. Even though the ocelli in this genus seems to be suffering evolutionary pressure to disappear, it can still be found in a reduced form in some species. We have modified the generic diagnosis to accommodate this variation.

Figures

FIGURES 1 – 5. Acrocephalomyia pulchra sp. nov.: Habitus: 1, lateral view; 2, dorsal view; Head: 3, dorsal view; 4, lateral view; 5, frontal view. Scale = 1 mm.