Chamaeleucopis trevas, Gaimari, Stephen D., 2012

Gaimari, Stephen D., 2012, A new genus and species of Chamaemyiidae (Diptera: Lauxanioidea) from South America feeding on Ceroplastes wax scales (Hemiptera: Coccidae), and status of the genus Ortalidina as a chamaemyiid, Zootaxa 3342, pp. 39-50 : 40-44

Chamaeleucopis trevas , sp. nov. ( Figs. 1–9 )

Etymology. From the Portuguese noun “ trevas ,” meaning darkness, referring to the dark body of this species; to be treated as a noun in apposition.

Diagnosis. The body is compact and stout, and overall dark in color, with a shiny black abdomen ( Fig. 1 ). On the frons, there are 2 strong fronto-orbital setae. Postocellar setae are absent, but ocellar setae are present, proclinate and diverging. The posterior ocelli are slightly farther apart than the distance between a posterior ocellus and the anterior ocellus. The lunule is wide, high and setulose. The antennae are mostly yellowish orange, except for the darker distal part of the 1st flagellomere, and they are separated by a distance equal to the width of one antennal socket. The palpus is large, spatulate and yellowish orange. The scutum is dark silvery-grey pruinose with diffuse brownish pruinose areas centrally, the scutellum is brown pruinose, while the pleuron is lighter silvery-grey pruinose. There are 2 dorsocentral setae located in the posterior part of the scutum, and prescutellar acrostichal setae are present. In the male genitalia, the pregonite is absent, while the postgonite is large, blunt, laterally flattened and spatulate.

Description. Adults, 3, Ƥ. Body length 2.1–2.2 mm (3, 2.2 mm; Ƥ, 2.1–2.2 mm).

Head ( Figs. 1–3 ). 1.6–1.9 X higher than long; 1.2–1.3 X wider than high. Vertex silvery grey, except for small brown spot anterior to vertical setae; with outer vertical seta slightly longer than inner one. Postocellar setae absent. Ocellar triangle silvery grey; with posterior ocelli separated by distance 1.4 X that between posterior and anterior ocellus; slightly raised, placed slightly anterior to vertex; with several setulae within triangle. Ocellar setae proclinate and diverging; originating at midpoint between anterior and one posterior ocelli. Eye 1.2–1.3 X higher than long; height 2.5–2.9 X genal height. Frons reddish brown, except for pale patch in front of anterior ocellus; 1.3–1.4 X wider than long; with lateral edges only slightly diverging anteriorly, 1.2–1.4 X wider at level of lunule than at level of anterior ocellus; with numerous reclinate setulae medially, and several proclinate setulae along eye margin anteriorly. Fronto-orbital area concolorous with central frons, except silvery-grey pruinose along eye margin; with 2 reclinate fronto-orbital setae, with anterior seta located at level of midpoint between anterior ocellus and edge of lunule, and with posterior seta located midway between anterior seta and vertical setae. Lunule light brownish grey above antennae, becoming silvery grey at level of antennae through face; wide and arched, height 0.6–0.7 X frons length; sloping to plane of frons above antennal base; with small, fine, proclinate setulae. Antenna yellow orange, except 1st flagellomere dark brown in distal half, and basal part of basal segment of arista black (remaining states of arista unknown due to breakage of all specimens); separated by slightly more than width of antennal socket; 1st flagellomere large, rounded. Face silvery grey; receding, with deep antennal grooves. Parafacial and gena brownish pruinose; gena with one strong genal seta in addition to several setulae above and behind. Clypeus black with sparse covering of silvery grey pruinescence; small, exposed. Palpus yellowish orange, darkest at tip; spatulate; with several scattered tiny setulae distally. Prementum and labellum yellow, small.

Thorax ( Figs. 1, 3 ). Scutum dark silvery-grey pruinose with diffuse brownish pruinose areas centrally; 1.1–1.2 X longer than wide; 3.9–4.4 X longer than scutellar length; setulose; dorsocentral vittae absent. Prescutellum present. Scutellum brown pruinose; 1.7–2.0 X wider than long. Pleuron entirely silvery-grey pruinose. Chaetotaxy: 0+2 dorsocentral setae located in posterior third of scutum, posterior seta 2 X longer than anterior one; one postpronotal seta; two notopleural setae, in anterior and posterior corners, posterior one slightly smaller; one pre- and one postsutural supra-alar seta; two postalar setae; one prescutellar acrostichal seta; proepisternum, anepisternum and anepimeron lacking setae; one strong katepisternal seta along upper edge, with several small setulae anterior to seta; two pairs scutellar setae. Legs. Femora greyish pruinose, with apex yellow. Tibiae greyish pruinose, with hind femur slightly flanged dorsally. Tarsi with tarsomeres 1–2 dark yellow, becoming darker through remaining tarsomeres. Wing. Length 2.0– 2.2 mm (3, 2.2 mm; Ƥ, 2.0– 2.2 mm); 2.6–2.8 X longer than high. Hyaline, with veins light brown. Veins R2+3, R4+5 and M1 parallel in distal half of wing. Crossvein r-m located slightly basad of halfway point of wing length, and at 3/5 point of cell dm-cu length. Crossvein bm-cu complete, fully separating cells dm and bm. Vein CuA1 extends to wing margin; apical section 0.8–1.1 X longer than crossvein dm-cu. Halter stalk brown, knob yellow.

Abdomen ( Fig. 4 ). Tergites shiny black; uniformly setulose, except setulae slightly enlarged along posterior margin, longest laterally. Syntergite 1+2 and tergite 3 of 3 apparently lacking patch of microtrichiae on lateral edge. Sternites black; sternites 3–5 subsquare, small, with sternite 5 slightly larger than preceding sternites; setulose, with longest setulae along posterior edge. Pregenital segments of male. Tergite and sternite 6 absent. Syntergosternite 7+8 a narrow strip, 1/3 length of preceding tergite, broad laterally, with heavy setulae on posterolateral part; sternite 7 apparently absent. Pregenital segment of female ( Fig. 9 ). Tergite 6 about 3.5 X wider than long, length 0.7 X length of tergite 5; sternite 6 enlarged, 2.2 X wider than long, 0.6 X width of tergite 6, and 2.7 X wider than sternite 5, setulose in posterior half, anterior and posterior margins emarginate.

Male genitalia ( Figs. 5–8 ). Epandrium strongly convex along posterior margin, with small, abruptly tapering sharp surstylar lobe; with series of long setae along inner edge, and patch of smaller setae distally. Cercus of moderate size, with short hairs, and with long hairs at apex. Subepandrial plate distinctly sclerotized, teardropshaped (rounded end distally), 2 X longer than wide; flanked by distinct subepandrial membrane. Hypandrium in ventral view a thin posteriorly curved transverse strip, widest at lateral edges; in dorsal view subequal in length and width, subcircular, with notch mediodistally and a lightly sclerotized window centrally; in profile distinctly undulate, widest dorsally before curving and thinning ventrally. Pregonite absent. Postgonite large, laterally flattened and spatulate. Phallapodeme in lateral view strongly upcurved and tapering to anterior point, and with deep notch on posterior edge; in ventral view club-shaped, expanded anteriorly. Phallus in lateral view gently curved and tapering distally, with pair of anteriorly directed inner processes; basiphallus with strong, wide medial connection to distal edge of hypandrium; in dorsal view, basiphallus broad, distiphallus strongly bifid with lateral arms slightly curved outward.

Female terminalia. Tergite 7 not evident or entirely membranous; sternite 7 ( Fig. 9 ) small (1/3 length and 0.4 X width of sternite 6), divided medially into two small elongate sclerotized patches; tergite and sternite 8 not evident, or entirely membranous. Hypoproct lightly sclerotized, tapering evenly to rounded tip. Epiproct subtriangular, with normal cercus bearing uniformly short setulae. Internally, spermathecae 2+2, round.

Immatures. Unknown.

Type material. Holotype 3 (point mounted; poor condition, head mounted separately on top of point, abdomen and genitalia in glycerin in glass vial mounted below labels), deposited in MZSP, with the following labels: “Piracicaba, SP, Set. 1978, E. Berti F o”/ “Ex Ceroplastes em Goiabeira” / “ SDG dissection 1370 3” / “ HOLOTYPUS 3 Chamaeleucopis trevas Gaimari ” (red label). Paratypes. BRAZIL. SÃO PAULO. Piracicaba, Piracicaba, ix.1978, coll. E. Berti Filho, ex. Ceroplastes scales on Gioabeira (= Psidium guajava ) [same data as Holotype] (2 ƤƤ (including SDG dissection 1386), MZSP; 2 ƤƤ, CSCA).

Distribution. Known from Brazil (São Paulo State).

Biology. Like the species of the chamaemyiid genus Echinoleucopis Gaimari & Tanasijtshuk , this species is predacious on wax scales in the genus Ceroplastes Gray ( Hemiptera : Coccidae ), presumably also feeding as an egg predator within a female ovisac. The only plant on which this species has been collected is guava, Psidium guajava L. ( Myrtaceae ). According to Ben-Dov (2011), 10 species of Ceroplastes known from Brazil (seven of which are known from São Paulo State) feed on guava.

Remarks. Despite the geographical proximity and similar life history of this species to those of Echinoleucopis , they are clearly not congeneric, although they share a rather robust body form, and a head that is much higher than long. Among other characteristics detailed in Gaimari & Tanasijtshuk (2001), the presence of 2 full-sized, widelyseparated fronto-orbital setae is unique to this new genus among New World Leucopini . In addition, species of Echinoleucopis lack ocellar setae, while in the new genus they are present, proclinate and diverging. The lunule is very high in Echinoleucopis , being subequal in length to the frons, while in the new genus the lunule is broad and comparatively low. A pair of prescutellar acrostichal setae is present in the new genus, and absent from Echinoleucopis . In males, the species of Echinoleucopis possess a distinct sternite 6, while this sternite is absent in the new genus. In females, sternite 7 is subdivided medially in both genera, but in Echinoleucopis the sternite is setulose while it is bare in the new genus; sternite 6 is comparatively massive in the new genus.

Although clearly different in gestalt and body size (species of the chamaemyiid genus Melaleucopis Sabrosky are less than 2 mm in length), this species shares several characteristics with Melaleucopis , including proclinate and divergent ocellar setae, presence of a fronto-orbital seta (only 1 in Melaleucopis ), and a shiny black abdomen. But this species differs from Melaleucopis in having a very wide lunule, a large spatulate palpus, 2 fronto-orbital setae, posterior ocelli that are slightly farther apart than the distance between a posterior ocellus and the anterior ocellus, and the frons being completely pruinose (shiny black in Melaleucopis ). In addition, crossvein bm-cu in the wing is complete (in Melaleucopis , this crossvein is stublike, incomplete, and does not fully separate cells dm and bm). They also differ in their life histories, with Melaleucopis species being predators of free-living Ortheziidae ( Beingolea 1957, Sabrosky 1957).

The new genus is also superficially similar to the Australian chamaemyiid genus Pseudoleucopis Malloch (e.g., the general body color, presence of two strong fronto-orbital setae), but differs in several critical characteristics, including a fully exposed lunule, and the absence of sternite and tergite 6, of sternite 7, and of pregonites in the male genitalia, in addition to the large, spatulate postgonite. In addition, the two genera are in two different tribes of Chamaemyiinae , with the new genus in the Leucopini and Pseudoleucopis in the Chamaemyiini ( Tanasijtshuk 1996) .

Figures

FIGURE 1 – 4. Chamaeleucopis trevas, sp. nov., paratype Ƥ. 1. Habitus, lateral view, scale bar = 0.5 mm. 2. Head, anterodorsal view. 3. Thorax and head, dorsal view. 4. Abdomen, dorsal view.

FIGURE 5 – 9. Chamaeleucopis trevas, sp. nov., holotype 3, genitalia (5 – 8), paratype Ƥ, sternites (9), scale bar = 0.01 mm. 5 – 6. Epandrial complex: 5. dorsal view, 6. lateral view. 7. Phallus complex, ventral view. 8. Phallus and phallapodeme, lateral view. 9. Female sternites 4 – 7, ventral view. bp = basiphallus; c = cercus; dp = distiphallus; e = epandrium; h = hypandrium; ip = inner process of phallus; pa = phallapodeme; pg = postgonite; S = sternite; ss = surstylar lobe.