Diastrophus brasiliensis, Oliveira & Melo, 2025

Diastrophus brasiliensis sp. nov.

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Figures 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4

Diagnosis. Diastrophus brasiliensis sp. nov. can be easily distinguished from all other species of Diastrophus by the following combination of features: surface of mesonotum strongly rugulose to rugose (mostly smooth and shiny in other species); dorsal axillar surface distinctly rugose (varying in other species from shiny to rugose); and mesopleuron medially with fine longitudinal striae (varying in other species from shiny, coriaceous, to striated). In addition, the new species can be distinguished from D. colombianus , the only other South American species, by its mostly rugulose mesoscutum (rugulosity in D. colombianus is restricted to the area between the parapsidal signa and the posterior half of the notauli) and its broadly and finely striated lateral mesopleuron (in D. colombianus , the mesopleuron is mostly smooth and the striation is restricted to a narrow medial band).

Description. Holotype female. Measurements (in mm). Approximate body length 2.8. Forewing length, including tegula, 3.8. Head length 0.8. Head width 0.9; POL 0.14; OOL 0.16. Color . Integument predominantly black. Mandible dark brown, teeth black distally. Tegula and antenna dark reddish brown. Coxae, trochanters, basal half of femora, and last tarsomeres brown; apical half of femora, tibiae and tarsomeres 1–4 reddish brown. Wing membrane mostly hyaline, with some infuscated regions, veins dark brown to black, 1 st abscissa of Rs (Median vein) and 2r-rs (2r) darker than remaining veins. Pilosity. Mostly pale and short. Antennae with scattered setae, each as long as half the width of F1. Head with very scattered setae. Anterior margin of clypeus and base of mandible with denser, longer setae. Pronotum moderately setose, especially on its lateral surface. Mesoscutum and scutellum very sparsely setose. Lateral mesopleuron glabrous, except for subalar triangle; ventral mesopleural area with scattered setae. Ventral metapleural area and lateral portion of propodeum densely setose. Legs densely setose, except for a glabrous stripe on the dorsal regions of the coxae, trochanters, and femora. Wing membrane homogeneously setose; setae about as long as half the width of Rs+M. Dorso-lateral area of T2 with a curved row of sparse, short setae. Posterior region of T6 and T7 with sparse, short setae. Hypopygial spine ventrally with a row of sparse, short setae on each side. Sculpturing. Face with strong, irregular carinae radiating from clypeus. Upper paraocular area with somewhat longitudinal carinae reaching antennal socket. Lower paraocular area with somewhat curved carinae near mandibles and lateral margin of clypeus. Clypeus with vertical striae. Gena, frons, and vertex coriaceous, very sparsely and shallowly punctate. Pronotum strongly rugose, especially on pronotal plate and dorsolateral areas; lateral area with well-developed longitudinal rugae. Mesoscutum with strong rugose sculpture, except for coriaceous area between parapsidal line and tegula. Scutellum strongly rugose, except for shiny scutellar foveae. Dorsal axillar surface rugose. Mesopleuron with longitudinal striae medially, striation broader near pronotum and becoming narrower toward metapleuron, giving the striated region a triangular form; dorsal and ventral areas of mesopleuron smooth; subalar triangle rugose. Metapleuron and propodeum rugose. Micropunctures present on posterior margins of both tergum and sternum of metasomal segments 4–7. Structure. Head in dorsal view 2.5x wider than long, slightly broader than mesosoma; rounded in frontal view, 1.25x wider than long. Gena in lateral view expanded, 0.5x as wide as compound eye. Clypeus subquadrate, about as wide as long; ventral margin weakly projecting over mandibles. Epistomal sulcus visible and slightly curved upwards. Malar space 0.6x as long as compound eye length. Antennal sockets situated slightly above midlength of compound eye. Right mandible with three teeth; left with two teeth. Antenna with 13 flagellomeres, all with visible placodeal sensilla; pedicel 1.3x as long; F1–F12 longer than wide, F1 about 3.5x as long as its maximum width, F2–F4 about 0.9x as long as F1, remaining flagellomeres gradually decreasing in length; F13 subtriangular, subequal in length to F12. Pronotal plate distinct. Notauli complete, distinct and deeply impressed. Parapsidal line distinct and deeply impressed. Scutellar foveae oval, 0.26x as long as scutellum; foveal septum triangular, about 0.5x as wide as scutellum at its widest region posteriorly. Forewing with radial cell 3x longer than wide; R1 and Rs not reaching anterior wing margin; areolet absent. Basitarsi as long as combined lengths of tarsomeres 2 and 3. T2 about one-third of metasoma length.

Male.As in female except as follows: body size tending to be smaller; F2–F4 about 0.8x as long as F1; metasoma more compact.

Etymology. The specific name is based on the country where the type series was collected.

Type material. Holotype ♀, “ Brasil, PR, Piraquara ,\ 25.5122ºS 49.0033ºW,\ 965m, G.A. R. Melo” “Nascido em 19.x.2024 \ de galha em ramo de\ Rubus coletada em\ 17.x.2024 ” GoogleMaps . Paratypes: 3 ♀ and 3 ♂, same data as holotype GoogleMaps ; 1 ♀, same data except “ Nascido em 16.x.2024 …” GoogleMaps ; 1 ♀ and 2 ♂, same data except “ Nascido em 17.x.2024 …” GoogleMaps ; 5 ♀, same data except “ Nascido em 21.x.2024 …” GoogleMaps ; 5 ♀ and 6 ♂, same data except “ Nascido em 25.x.2024 …” GoogleMaps ; 3 ♀ and 7 ♂, same data except “ Nascido em 26.x.2024 …” GoogleMaps ; 7 ♀ and 8 ♂, same data except “ Nascido em 28.x.2024 …” GoogleMaps ; 12 ♀ and 2 ♂, same data except “ Nascido em 29.x.2024 …” GoogleMaps ; 7 ♀ and 4 ♂, same data except “ Nascido em 1.xi.2024 …” GoogleMaps ; 6 ♀ and 6 ♂, same data except “ Nascido em 4.xi.2024 …” GoogleMaps ; 7 ♀ and 1 ♂, same data except “ Nascido em 6.xi.2024 …” GoogleMaps ; 4 ♀ and 1 ♂, same data except “ Nascido em 9.xi.2024 …” GoogleMaps ; 4 ♀ and 2 ♂, same data except “ Nascido em 11.xi.2024 …” GoogleMaps ; 2 ♂ “ Brasil, PR, S.J. Pinhais ,\ 25.605ºS 49.193ºW,\ 880m, 1–30.x.2016,\ A. C. Domahovski ” GoogleMaps ; 1 ♀, same data except “ 1–30.x.2019 ”. The holotype and GoogleMaps 100 paratypes are deposited in the DZUP collection ; 6 ♀ and 4 ♂ paratypes will be sent to the MZSP collection .

Variation. In some females, the last flagellomere is fused with the preceding one, resulting in antennae with only 12 flagellomeres. Sometimes, this is observed in only one of the antennae. This fusion can also be partial and the constriction between the last two flagellomeres being perceptible on one side only. In males, the length of the 13 th flagellomere can be variable, with most of them having a short F13, as in most females, while in some the F13 is slightly longer than F12. In a single male, we observed a partial constriction on its long F13, giving the impression of antennae with 14 flagellomeres.

Biology. Two species of Rubus , R. brasiliensis Mart. and R. sellowii Cham. & Schlitdl. , were confirmed as host plants for D. brasiliensis sp. nov. The galls were generally cryptic ( Fig. 5 View FIGURE 5 ), with less pronounced external hypertrophy of the plant tissues. However, galls on R. sellowii ( Fig. 6A–D View FIGURE 6 ) exhibited more pronounced hypertrophy compared to those on R. brasiliensis .

A single galled branch of R. sellowii was obtained on May 25 th. Upon its partial dissection ( Fig. 6A–D View FIGURE 6 ), carried out three days later, we obtained a few larvae that were identified as belonging to Diastrophus based on their asymmetrical mandibles (see Nieves-Aldrey et al. 2005). Identification of the larvae was corroborated by the CO1 sequence obtained from one of them (L 3 in Fig. 1 View FIGURE 1 ). Three females (May 29 th, June 20 th, 2024) and one male ( June 6 th, 2024) of Torymidae , plus one female and one male ( June 18 th, 2024) of Eurytomidae emerged from this branch, but no adult Diastrophus .

During a second visit to the sampling site, we obtained additional galled branches from R. brasiliensis ( Fig. 5 View FIGURE 5 ). The branches already had many emergence holes and several adult Diastrophus emerged in the subsequent weeks (see Type Material). Dissection of one branch, on the collecting day, revealed both white and pigmented pupae of Diastrophus within the gall chambers ( Fig. 6E–F View FIGURE 6 ). In addition to the Diastrophus adults, the following insects emerged from the galled branches of R. brasiliensis : 9 females of Eulophidae ; 6 females and 2 males of Eurytomidae ; 9 females of Ichneumonidae (Orthocentrinae); 2 females of Pteromalidae ; 1 male of Torymidae ; and 4 females and 4 males of Sciaridae ( Diptera ). These other Hymenoptera are likely inquilines of the Diastrophus galls or their larval parasitoids, except for the Orthocentrinae ichneumon wasps, which are known to attack Sciarioidea (see Gauld 2006: 480).