Leucotaraxis atrifacies (Aldrich) 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 : 16-17

Leucotaraxis atrifacies (Aldrich) , comb. nov.

( Figs 1A , 2C–D , 3B, 3F–G )

Leucopis atrifacies Aldrich 1925: 152 . United States. California: San Francisco (HT ♀, USNM). References – McAlpine 1965: 709 (catalog); Cole & Schlinger 1969: 376 (note); Tanasijtshuk 2002: 194 (redescription), figs 1–2 (head), figs 3–5 (♂ genitalia); Havill et al. 2018: 26 (relationships).

Diagnosis. The face and lunule ( Figs 2C–D ) are dark brown to black pruinose. The postpronotum (as in Fig. 2E ) has 1 strong postpronotal seta, and no additional setulae longer than those on the scutum. In the male (see figs 3–5 in Tanasijtshuk 2002), the epandrial complex is simple, small, and yellowish- to silvery-grey pruinose, with no central epandrial process; the surstylar lobe is short and stout; the phallus ( Fig. 3B ) is long and thick in lateral view, less than 8 X longer than its height at the middle, and is straight-sided until an abrupt distal curve to a pointed tip. In the female ( Fig. 3G ), tergite 6 enlarged and about 1.6 X wider than long, tergite 7 present and strap-like, tergite 8 longer than wide, bone-shaped, narrowest through middle; sternites ( Fig. 3F ) with sternite 6 more than 2 X wider than long and slightly concave medially on both anterior and posterior margins, sternite 7 absent.

Immatures. Egg ( Fig. 1A ). Length 0.42–0.47 mm, width 0.14–0.17 mm. Puparium. Length 1.9–2.2 mm, width 0.7–0.9 mm. Dehiscent anterior segments (dorsal and ventral) 0.04–0.06 mm long. Raised posterior spiracular tubercles 0.07–0.11 mm long, with sclerotization concolorous with remainder of puparium (as in Fig. 1D ).

Biology. Predators as larvae on species of Adelges and Pineus on Pinaceae ( Pinus , Tsuga ). Specific records include their attacking Adelges piceae and a Pineus sp. , and adelgids (presumably Pineus sp. ) infesting Pinus radiata and Pinus edulus . A larva was collected from Pineus coloradensis on Pinus ponderosa . Many 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 atrifacies is also a predator in that system, whether on the Cinara aphids or on adelgids unseen by the first author while collecting.

Remarks. This species was originally described from specimens reared by Eric Walther “in connection with Thecodiplosis pini-radiatae ” (= Thecodiplosis piniradiatae (Snow & Mills) , Cecidomyiidae ), the Monterey pine midge. This midge forms galls at the bases of needles of several species of Pinus including Pinus coulteri , P. radiata and P. sabiniana , and although they likely do not share a true association, it makes sense for them to be together on a tree infested with both the midge and adelgids.

At two different localities (one in New Mexico and one in Arizona), this species was collected together with Chamaethrix necopina, Leucotaraxis argenticollis and Vitaleucopis nidolkah , and at the New Mexico locality also with Leucotaraxis sepiola . This species was also collected at a different New Mexico locality with Leucotaraxis sepiola , and at the southern California locality along with the undescribed species of Vitaleucopis cited in Gaimari (2020). The puparial stage is indistinguishable from that of Leucotaraxis piniperda , both of which are only distinguishable from Leucotaraxis argenticollis by the shorter posterior spiracular tubercle which is not more darkly sclerotized distally, and the slightly smaller size.

Given the few specimens known from Mexico are from the south of the country and quite distant from other known specimens, it is expected that this species inhabits the areas dominated by Pinus in Mexico, at least as far south as the Popocatépetl volcano. More rearing and collecting in Mexico will be necessary to understand the extent of its distribution south of the USA.

Distribution. Mexico (Durango, Mexico State). USA (Arizona, California, Colorado, New Mexico, Washington).

Specimens examined. All specimens from Tanasijtshuk (2002) were examined, with additional specimens as follows. MEXICO: MEXICO. San Pedro Nexapa, nr. Amecameca, foot of Popocatépetl (volcano), 19°04’23.89”N 98°42’04.04”W, 2955 m, 7.vii.2011, coll. N.P. Havill, W. Gloria, A. Gloria-Soria, ex. on Pinus sp. (5-needle) infested with Pineus sp. (2 ♂ with puparia, CSCA). USA: ARIZONA. Apache Co., Apache National Forest, 0.3 mi. S mi. 249 on US Route 191, 5 mi. S Alpine, along Coleman Creek, 33°47’24”N 109°10’01”W, 2500 m, 30.vi.1995, coll. S.D. Gaimari, ex. sweep Pinus ponderosa (1 ♀, CSCA), 1.vii.1995 (1 ♀, CSCA); nr. Alpine, 33°51’52”N 109°10’18”W, 2440 m, 28.vi.1995, coll. S.D. Gaimari, ex. sweep young Pinus ponderosa (1 ♀, CSCA). CALIFORNIA. Los Angeles Co., La Crescenta, Eagle Canyon, S base Mount Lukens, 29.vi.1994, coll. S.D. Gaimari, ex. Sharkey Malaise trap near stream (1 ♂, CSCA). COLORADO. Alamosa Co., 21 mi. ENE Mosca, 37°45’02”N 105°30’14”W, 8100 ft., 19–22.vi.1996, coll. S.D. Gaimari, ex. Malaise trap (1 ♀, CSCA). NEW MEXICO. Lincoln Co., Lincoln National Forest, 2.4 km W Angus, Mills Canyon, along Rio Bonito, 33°27’05”N 105°41’46”W, 2130 m, 18–19.vi.1995, coll. S.D. Gaimari, ex. sweep colonies of Cinara ponderosae on Pinus ponderosa (1 ♂, 3 ♀, CSCA), 23.vi.1995 (1 ♂, 3 ♀, CSCA), 24.vi.1995, Specimen #09E474 (1 ♂ [molecular voucher], CSCA), Specimen #09E478 (1 ♂ [molecular voucher], CSCA), Specimen #09E479 (1 ♂ [molecular voucher], CSCA), Voucher #09E519 (2 ♂, 8 ♀, CSCA-FTC), 25.vi.1995, Specimen #09E480 (1 ♂ [molecular voucher], CSCA), Voucher #09E513 (1 ♀ (SDG dissection #1379), CSCA-FTC), Specimen #10F334 (1 ♀, CSCA), Specimen #10F335 (1 ♀ (SDG dissection #1380), CSCA-FTC), Specimen #10F336 (1 ♀ (SDG dissection #1381), CSCA-FTC), Specimen #10F337 (1 ♀, CSCA-FTC), Specimen #10F338 (1 ♀, CSCA-FTC), Specimen #10F339 (1 ♀, CSCA-FTC), Specimen #10F340 (1 ♀ (SDG dissection #1382), CSCA-FTC), Specimen #10F341 (1 ♀ (SDG dissection #1383), CSCA-FTC), Specimen #10F342 (1 ♀, CSCA-FTC), Specimen #10F343 (1 ♀, CSCA-FTC), Specimen #10F344 (1 ♂, CSCA-FTC), Specimen #10F345 (1 ♂, CSCA-FTC), 26.vi.1995, Specimen #09E523 (1 ♀ (SDG dissection #1372), CSCA-FTC), Specimen #10F346 (1 ♀, CSCA-FTC), Specimen #10F347 (1 ♀ (SDG dissection #1374), CSCA-FTC), Specimen #10F348 (1 ♀ (SDG dissection #1375), CSCA-FTC), Specimen #10F349 (1 ♀ (SDG dissection #1376), CSCA-FTC), Specimen #10F350 (1 ♀ (SDG dissection #1377), CSCA-FTC), Specimen #10F351 (1 ♀ (SDG dissection #1378), CSCA-FTC), Specimen #10F353 (1 ♀ (SDG dissection #1372), CSCA-FTC), Specimen #10F726 (1 ♂, CSCA), Voucher #09E515 (5 ♀, CSCA-FTC); White Mountains, along Fork Creek, 3.1 mi. W Alto, 33°23’31.2”N 105°43’57.0”W, 2365 m, 15.vi.2007, coll. S.D. Gaimari, ex. sweep Pinus ponderosa with Cinara ponderosae infestation (1 ♂, 1 ♀, CSCA). McKinley Co., Cibola National Forest, Zuni Mountains, 4 mi. SSW Fort Wingate, 35°25’20”N 108°34’38”W, 7900 ft., 24.vi.1996, coll. S.D. Gaimari, ex. sweep Pinus ponderosa (8 ♂, 9 ♀, CSCA), 4.4 mi. SE Fort Wingate, 35°25’49”N 108°29’17”W, 7300 ft., 25.vi.1996, ex. sweep Pinus edulus (4 ♀, CSCA). WASHINGTON. Ferry Co., Colville Reservation, Inchelium, 48.3109°N 118.2017°W, 22.vii.2019, coll. D. Dickenson, ex. Pineus coloradensis on Pinus ponderosa , sample 19- 176-05 (1 ♂, on slide, YPM; ENT960794).

Figures

FIGURE 1. Immature stages of Leucotaraxis species. A. L. atrifacies, egg, dorsal view, posterior pole right (measure bar = 0.1 mm). B–C. L. argenticollis, puparium, dorsal view: B. habitus (measure bar = 0.2 mm); C. posterior spiracles. D. L. piniperda, puparial posterior spiracles, dorsal view.

FIGURE 2. Leucotaraxis species. A–B. L. argenticollis: A. head and thorax, lateral view; B. head, anterior view. C–D. L. atrifacies: C. head and anterior thorax, lateral view; D. head, anterior view. E–H. L. piniperda: E. head and thorax, lateral view; F–H. heads, anterior view: F. eastern form; G. mixed form; H. western form.

FIGURE 3. Terminalia of Leucotaraxis species. A–C. Male, phallus, oriented with distal part right (measure bar = 0.1 mm): A. L. argenticollis; B. L. atrifacies; C. L. piniperda. D–H. Female, terminalia. D–E. L. argenticollis: D. ventral view; E. dorsal view. F–G. L. atrifacies: F. ventral view; G. dorsal view. H. L. piniperda, dorsal view. Numbers to the left indicate segments (D, F are sternites; E, G, H are tergites).