Leucotaraxis sepiola, Gaimari & Havill, 2021

Gaimari, Stephen D. & Havill, Nathan P., 2021, A new genus of Chamaemyiidae (Diptera: Lauxanioidea) predaceous on Adelgidae (Hemiptera), with a key to chamaemyiid species associated with Pinaceae-feeding Sternorrhyncha, Zootaxa 5067 (1), pp. 1-39 : 21-24

Leucotaraxis sepiola sp. nov.

urn:lsid:zoobank.org:act:462348DE-B22C-4463-A4CB-91FB7D1F4AD0

( Figs 4A–H , 5A–C )

Etymology. From the diminutive of the Latin noun sepia, referring to squid ink, in reference to the large, distinctive, shiny black epandrium and cerci in the male of this species; a noun.

Diagnosis. The face and lunule ( Figs 4B, D ) are dark brown to black pruinose. The postpronotum ( Figs 4A, G ) has 1 strong postpronotal seta, and no additional setulae longer than those on the scutum. In the male genitalia ( Figs 5A–C ), the epandrial complex is large, conspicuous and polished black, with the epandrium extending into a central process bearing the cerci at a distinct upward angle; the surstylar lobe is articulated with the epandrium and is long and thin.

Adults, ♂ (♀ unknown). Body length 1.8 mm.

Head ( Figs 4B–F ). 1.4 X higher than long; 1.3 X wider than high; mostly dark silvery grey with exceptions following. Vertex with outer vertical seta longer than inner one by 1.5 X. Postocellar setae absent. Ocellar triangle tapering to about midpoint of frons, slightly raised from fronto-orbital plate; posterior ocelli farther apart than distance to anterior ocellus by 1.5 X; anterior ocellus slightly smaller than posterior; posterior ocelli placed slightly anterior to vertex, with area between and behind posterior ocelli lacking setulae. Ocellar setae absent. Eye with length and width subequal; height 2.6 X genal height. Frons with reddish grey strip along edge of ocellar triangle ( Fig. 4F ); 1.3 X wider than long; with lateral edges only slightly diverging anteriorly, 1.1 X wider at level of lunule than at level of anterior ocellus; meeting lunule at 90° angle. Fronto-orbital setae lacking; area setulose (setulae erect, white) distally ( Figs 4C, E ). Lunule ( Figs 4B–D ) dark brown pruinose above antennae; anterior edge straight, height 0.5 X frons length; with few small, fine setulae. Antennae entirely dark brown to black; separated by distance less than 0.5 X antennal socket width, lacking carina, with area between antennal bases darkening to black pruinose ventrally (as in face); 1st flagellomere short, rounded, covered with short brown hairs; arista with distal segment 3.0 X longer than basal. Face black pruinose; with deep antennal grooves. Parafacial black pruinose; about half width of facial width. Gena with one strong genal seta in addition to one strong setula and several small setulae behind. Clypeus black with sparse covering of dark grey pruinosity; small, exposed. Palpus dark brown; cylindrical; setulose. Mouthparts very small and held within oral cavity above palpi; prementum dark, small; labellum small, yellow.

Thorax ( Figs 4A, D ). Scutum uniformly dark silvery-grey pruinose; 1.3 X longer than wide; 4.0 X scutellar length; setulose; dorsocentral vittae absent. Prescutellum present. Scutellum concolorous with scutum; 1.7 X wider than long. Pleuron concolorous with scutum. Chaetotaxy: 0+2 dorsocentral setae, posterior seta 1.5 X longer than anterior one; one postpronotal seta; two notopleural setae, in anterior and posterior corners, anterior one 3.0 X longer than posterior one; one pre- and one postsutural supra-alar seta; two postalar setae; prescutellar acrostichal seta absent; proepisternum, anepisternum and anepimeron lacking setae; one strong katepisternal seta along upper edge, with 3 or 4 small setulae in row anterior to seta; two pairs scutellar setae. Legs. Entirely dark brown, except for femora and tibiae dark grey pruinose with orange distal tips of femora and basal parts of tibiae, with basal parts of basotarsomeres lighter brown. Wing. Length 1.6 mm; 2.6 X longer than wide. Hyaline, with veins brown. Veins R 2+3, R 4+5 and M 1 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 length. Vein CuA 1 extends to wing margin; apical section 2.0 X longer than crossvein dm-cu. Halter yellow, with stalk slightly darker.

Abdomen ( Fig. 4H ). Tergites uniformly setulose, except setulae very slightly enlarged along posterior margin and laterally. Syntergite 1+2 and tergite 3 bronzy pruinose, except lateral parts dark silvery-grey pruinose; tergites 4–6 dark silvery-grey pruinose. Syntergite 1+2 and tergite 3 lacking patch of microtrichiae on lateral edge. Sternites dark silvery-grey pruinose.

Male genitalia ( Figs 5A–C ). Epandrium large, convex posteriorly, entirely shiny black, with series of very small setulae along posterior edge; extending distomedially into blunt projection which bears cerci on ventral surface, with small central depression on anterodorsal surface;with long,narrow,medially-oriented surstylar lobe.Cercus large,padlike; shiny black, oriented downwards from posterior surface of distomedial extension of epandrium; in lateral view, subequal in size and general shape to hypandrium. (Note, phallus complex severely over-macerated after soaking in KOH with heavy and dark epandrial complex, resulting in the structures shrivelling and becoming twisted. As such, the following characteristics were not illustrated, but are described as well as possible after thorough examination, to be verified when this species is again collected: Hypandrium in dorsal view subovate, 1.3 X longer than wide, with lateral arms very thick to point of articulation with postgonite, becoming abruptly thin posteriorly; in profile, subquadrate, evenly wide. Pregonite absent. Postgonite flattened, curved, with blunt tip; dorsally setulose; lightly sclerotized. Phallapodeme about 2 X longer than high from lateral view, parallel-sided; in ventral view, bone-shaped, about 3 X longer than wide. Phallus from ventral view parallel-sided to blunt tip, 2.2 X longer than wide; from lateral view, length 4.0 X height of basiphallus, basiphallus extending into small subtriangular lobe, distiphallus slightly curved, evenly narrow to blunt tip).

Immatures. Unknown.

Biology. All known specimens were swept from infestations of Cinara ponderosae in young stands of Pinus ponderosa (e.g., height less than 5 m throughout the large stand), but despite rearing>150 chamaemyiid larvae from this host, none were this species, but were instead Vitaleucopis nidolkah and an undescribed species of Leucopis (Leucopis) . It remains a possibility that Leucotaraxis sepiola is a predator in that system, whether on the Cinara aphids or on adelgids unseen by the first author while collecting.

Remarks. At one locality in New Mexico, this species was collected together with Chamaethrix necopina, Leucotaraxis argenticollis, Leucotaraxis atrifacies and Vitaleucopis nidolkah , and at an additional New Mexico locality along with Leucotaraxis atrifacies .

Distribution. Known only from New Mexico.

Type material. Holotype ♂ (point mounted, very good condition), deposited in CSCA, with the following labels: “USA. NEW MEXICO. Lincoln Co., 2.4 km W Angus, Lincoln Nat’l For. , White Mts. Wilderness , head of Mills Cyn. trail along Rio Bonito , el. 2130 m, 33°27’05”N 105°41’46”W, 26 JUN 1995, S.D. Gaimari, ex. sweep Cinara ponderosae on Pinus ponderosa ” / “HOLOTYPUS ♂ Leucotaraxis sepiola Gaimari ” (red label). Paratypes: USA: NEW MEXICO. Lincoln Co., 2.4 km W Angus, Lincoln National Forest, White Mountains Wilderness , head of Mills Canyon trail, along Rio Bonito , 33°27’05”N 105°41’46”W, 2130 m, 26.vi.1995, coll. S.D. Gaimari, ex. sweep Cinara ponderosae on Pinus ponderosa [same data as holotype], Specimen #10F352 (1 ♂ [molecular voucher] (SDG dissection 1371), CSCA). McKinley Co., 4 mi. SSW Fort Wingate , Cibola National Forest , Zuni Mountains , 35°25’20”N, 108°34’38”W, 2408 m, 24.vi.1996, coll. S.D. Gaimari, ex. sweep Pinus ponderosa (1 ♂, CSCA).

Figures

FIGURE 4. Leucotaraxis sepiola, male, external features. A. Habitus, lateral view (paratype). B–F. Head: B. anterior view (holotype); C–D. oblique view: C. showing setae along edge of frons (paratype); D. entire (holotype); E–F. dorsal view: E. showing setae along edges of frons (paratype); F. entire (holotype); G–H. dorsal view (holotype): G. head and thorax; H. abdomen.

FIGURE 5. Leucotaraxis sepiola, male, genitalic features. A–B. Holotype: A. lateral view; B. posterolateral view. C. Paratype, posterolateral view, with surstylus oriented medially under cercus.