Pachysvastra luquita Alvarez & Lucia, 2024

Alvarez, Leopoldo J. & Lucia, Mariano, 2024, A new species of Pachysvastra Moure & Michener (Hymenoptera: Apidae) discovered in Argentina, Zootaxa 5471 (3), pp. 391-397 : 392-396

Pachysvastra luquita Alvarez & Lucia , new species urn:lsid:zoobank.org:act:B0A4F19A-A622-425A-9A6E-F902353713AC

Diagnosis. The female of P. luquita can be easily distinguished from P. leucocephala by the clypeus with a subapical yellow band (black in P. leucocephala ) and by the vertex and mesosoma with mixed white and black hairs and hind legs with yellowish pubescence (hairs black in P. leucocephala ). Female P. luquita superficially resembles P. flavofasciata , since both species present a maculated clypeus, translucent light brown marginal bands on T1–T4, and yellow hairs on the hind legs. However, P. luquita differs by the vertex and mesosoma with mixed white and black hairs, the pronotal lobe with a distinct tuft of long black hairs (hairs yellow in P. flavofasciata ), the clypeus with a broad subapical yellow band occupying 0.45× the length of the clypeus (0.25× in P. flavofasciata ), the broad, translucent light brown marginal bands on T1–T4, 1.3–1.6× MOD long (~1× MOD long in P. flavofasciata ), the presence of hairs apically curved on the galea (absent in P. flavofasciata ), the shorter ocellocular distance 2.3× MOD long (2.7× MOD long in P. flavofasciata ) and by the interocellar distance to ocellocular distance 0.9:1 (1.16: 1 in P. flavofasciata ). The male clypeus has a broad subapical yellow band occupying 0.6× of its length. It can be easily distinguished from P. leucocephala , in which the clypeus is almost yellow. The male of P. flavofasciata is unknown.

Description. Holotype female. Structure. Total body length 10 mm (paratypes 10–10.5), head width 4 mm (paratypes 4.2–4.3), length of forewing 8.4 mm (paratypes 8.2–8.6). Head wider than long, length 3.6 mm, width 4 mm; inner margins of compound eye converging below, upper interorbital distance 2.5 mm and lower interorbital distance 2.3 mm. Ocellocular distance 2.3× MOD long, interocellar distance shorter than ocellocular distance (0.9:1). Clypeus weakly protuberant, length of scape 0.8 mm, pedicel 0.2 mm and first flagellomere 2.2× as long as second flagellomere; second flagellomere slightly shorter than third flagellomere. Intertegular distance 2.7 mm. Clypeus with dense and shallow punctures, coarser anteriorly, with integument smooth between punctures. Disc of mesoscutum uniformly punctured, with coarse punctures, punctures contiguous laterally, becoming sparser medially, integument smooth between punctures. Disc of T1–T5 with small, distinct, uniform, punctures; apical margin of terga impunctate, wider on T1 approximately a MOD long, T2–T4 0.3× MOD long; graduli of T2–T5 carinate laterally. Colouration. Integument dark brown to black throughout, except clypeus with a broad subapical yellow band occupying 0.45× length of clypeus ( Fig. 1b ), distal portion of the mandible and posterior tibia and tarsus light brown; T1–T4 with broad translucent light brown marginal bands, 1.3–1.6× MOD long ( Fig. 1c ), S2–S4 with a narrow translucent light brown marginal zone. Wings subhyaline, veins and pterostigma dark brown. Pilosity. Head with whitish plumose hairs; except vertex with intermixed black and white, plumose hairs; gena with appressed white hairs; clypeus and labrum with short and appressed hairs and apical margin of labrum and mandible with light brown hairs. The stipes, galea, and prementum with hairs apically curved. Mesosoma with pilosity mixed white and black, pronotal lobe with a distinct tuft of long, black hairs. Legs with pilosity pale except pro and mesotarsus with brown hairs, hind leg with yellowish hairs on scopa ( Fig. 1a ), and basitarsus with ferrugineous hairs on the inner surface. Lower portion of mesepisternum, coxae, and trochanters with modified, apically curved hairs. Basal half of T1 with abundant white, plumose hairs, on disc with dark brown, short, and simple hairs. T2–T4 with whitish, plumose hairs forming entire basal and subapical bands; medial surface of disc of T2–T4 with dark brown, short, and simple hairs (0.5× MOD long); on T3–T5 with long erect dark brown simple hairs (1.2× MOD long) more abundant on T4 and T5; T5 completely covered with hairs, white on basal half and dark brown on apical half; T6 with dark brown pilosity. Sterna with simple brown pilosity, basal area of S3–S5 with stripes of white short plumose hairs.

Male: Structure. Total body length 10–10.6 mm, head width 3.5–3.9 mm, length of forewing 7.2–8.5 mm ( Fig. 2a ). Head wider than long, length 2.4 mm, width 3.6 mm; inner margins of compound eye slightly converging below, upper interorbital distance 2.1 mm and lower interorbital distance 2 mm. Clypeus weakly protuberant, length of scape 0.6–0.7 mm, pedicel 0.16–0.2 mm and first flagellomere 0.5× as long as second, which is slightly shorter than third. Intertegular distance 2.3–2.5 mm. Clypeus with dense and shallow punctures, coarser anteriorly, integument smooth between punctures. Mesoscutum uniformly punctured, with coarse punctures, contiguous laterally, integument smooth between punctures. Discs of T1–T6 with small, distinct, uniform, punctures; apical margins of terga impunctate, wider on T1, 0.7× MOD long, and on T2–T5, 0.3× MOD long; graduli of T2–T7 conspicuous, strongly lamellate laterally, and on T6–T7 forming obtuse tooth; pygidial plate bilobed, with lateral and apicolateral margins carinate ( Fig. 2c ). Colouration. Integument dark brown to black throughout, except clypeus with broad subapical yellow band occupying 0.6× of its length ( Fig. 2b ); distal portion of mandible yellow, flagellum light brown; T1–T6 with broad translucent light brown marginal bands, 1–1.4× MOD long ( Fig. 2c ), apex of marginal zones of S1–S5 with a narrow, translucent light brown marginal zone; wings subhyaline, veins and pterostigma dark brown. Pilosity. Head with whitish plumose hairs; gena with appressed white hairs; clypeus and labrum with short and appressed hairs and apical margin of labrum and mandible with light brown hairs; stipes, galea, and prementum with simple hairs; dorsal surface of mesosoma with mixed white and yellowish hairs; mesosoma laterally and sterna with white pilosity; legs with short, plumose, pale hairs, except short and ferruginous hairs on posterior surface of metatibia; metasomal terga with white appressed plumose hairs, except on discs of T1 and T2 with light brown, short simple hairs; and intermixed on T3–T6 with short erect simple, light brown hairs (0.4–0.6× MOD long); sterna with simple brown pilosity, and S2–S5 with basal band of white short plumose hairs. S7 with apicomedian processes broadened apically, ventrally reflexed and divergent, with ventral face covered with long, apically branched bristles ( Fig. 2d ). S8 emarginate between apical lobes and with high medial longitudinal carina on ventral surface ( Fig. 2e ). Genitalia as in Fig 2f , distal portion of gonocoxite with ventral bristle organ (sensu Urban, 1974), with short and thick bristles of about 0.04 mm in length.

Type Material: Holotype; female, MLP, N° 5871/1 : ARGENTINA, Formosa, Pilcomayo , P.N. Pilcomayo (- 25.171, -58.13), 10-I-2019, S/ Thalia geniculata . Col. L. Alvarez, J.P. Torretta y A. Avalos. Paratypes: 1 ♂, with same data as holotype ( MLP) ; 1 ♂, with same data as holotype ( MACN) , 1 ♂, with same data as holotype ( DZUP) ; 1 ♂, Rep. Argt., Terr. Formosa, Gran Guardia . Col. J. Foerster // Pachysvastra leucocephala (Bert. y Schott) Det. A. Ogloblin // ( MLP) ; 1 ♀, Rep. Argt., Terr. Formosa, Gran Guardia . Col. J. Foerster ( MLP) ; 1 ♀, Misiones, Bompland , 31-I-1911, Col. Jörgensen //181// ( MLP) .

Etymology. The new species name is proposed in honour of our dearest friend Dr. Lucas Raimundo Bustos (warmly called “Luquita”), recently deceased, who was our fellow student during our university studies, then biologist, and mayor of the Los Cordones National Park in Salta Province, Argentina.

Distribution. This species occurs in Misiones and Formosa, Argentina ( Fig. 3 ), in an area included within the Chaqueña and Paranaense biogeographic provinces. This represents the southernmost distribution area of the genus since Pachysvastra leucocephala occurs in central and southeastern Brazil, Cuiabá (Mato Grosso), Goiânia (Goiás), southern Minas Gerais and Rio Claro (São Paulo) and P. flavofasciata is known only from Palmeira (Paraná) ( Urban et al. 2022).

Comments. Males and females of P. luquita were collected on flowers of Thalia geniculata L. ( Marantaceae ). This plant is distributed from southern Florida ( United States) to the center of Argentina ( Zanotti et al. 2018), growing in Argentina in different habitats, such as swampy and open areas.

Figures

FIGURE 1. Holotype female of Pachysvastra luquita sp. n. a, habitus, lateral view; b, head, frontal view; c, metasoma, dorsal view.

FIGURE 2. Male of Pachysvastra luquita. a, habitus, lateral view; b, head, frontal view; c, metasoma, dorsal view; d, S7, ventral view; e, S8, ventral view, and f, genital capsule, dorsal view.

FIGURE 3. Collection localities for species of Pachysvastra in Argentina and Brazil. Blue circles; P. leucocephala; red stars: P. flavofasciata and yellow triangles: P. luquita.