Trissolcus adrianae Costa & Johnson 2025, sp. nov.
Creators: name: Costa, Valmir A.
name: Johnson, Norman
name: Salomão, Adriana
name: Vasconcellos-Neto, João
name: Wengrat, Ana
name: Schoeninger, Karine
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Scelionidae
Trissolcus
Trissolcus adrianae

description: Trissolcus adrianae Costa & Johnson sp. nov.
Figs 1–5, 6–11, 12
GenBank accession number.
OQ 720992.
Diagnosis.
Trissolcus adrianae Costa & Johnson, sp. nov. is a distinctive species which is easily distinguished from other members of the flavipes group by its noticeably depressed habitus; head oblong in anterior view; mandible with only two teeth; frontal depression delimited dorsally by carina; orbital furrow sculptured, constricted through most of its length by lateral expansion of frons; notauli absent; and length of T 2 subequal to length of T 3 – T 6.
Description (female).
Body length: 2.18–2.44 mm (n = 12). Habitus: distinctly depressed dorsoventrally (Fig. 1).
Color. Body: head, mesosoma, and metasoma black. Color of radicle: yellow to dark brown. Color of A 1 – A 6: A 1, A 2 yellow, otherwise brown. Color of A 7 – A 11: brown. Coxae: brownish yellow. Legs beyond coxae: brownish yellow.
Head. Claval formula: 1-2 - 2 - 2 - 2. Shape of head in anterior view: oblong (Fig. 2), distinctly bulging between antennal insertion and inner orbits. Shape of head in lateral view: strongly protruding anteriorly (Fig. 3). Number of mandibular teeth: two (Fig. 4). Number of clypeal setae: 4. Facial striae: absent. Shape of gena in lateral view: receding posteriorly. Genal carina: absent. Macrosculpture of lateral frons: absent. Microsculpture of lateral frons: punctate, with large, well-defined setigerous punctures irregularly distributed as on vertex, interspaces smooth. Macrosculpture inside antennal scrobe: transversely rugulose. Frontal depression: delimited dorsally by carina (Fig. 2). Orbital furrow: present, constricted through most of its length by lateral expansion of frons (Figs 2, 4). Hyperoccipital carina: weakly developed (Fig. 5). Vertex: angulate, particularly laterally. Preocellar pit: present.
Mesosoma. Epomia: absent. Netrion sulcus: complete but obscured by coarse pronotal sculpture. Mesoscutal suprahumeral sulcus: not distinguishable from surrounding surface sculpture. Mesoscutal humeral sulcus: present as a thin groove. Pattern of mesoscutal microsculpture: absent between punctures. Macrosculpture of mesoscutum: punctate, with large, well-defined setigerous punctures irregularly distributed as on vertex. Area bounded by axillar crescent: smooth. Parapsidal signum: absent. Notaulus: absent (Fig. 6). Median mesoscutal line: absent. Median mesoscutal sulcus: absent. Sculpture of mesoscutellum: punctate, with large, well-defined setigerous punctures irregularly distributed as on vertex, interspaces smooth. Postacetabular sulcus: comprised of cells (Fig. 7). Episternal fovea: present. Shape of episternal foveae: elongate with rounded edges. Number of episternal foveae: 3–5. Course of episternal foveae ventrally: abutting cells of postacetabular sulcus. Course of episternal foveae dorsally: extending dorsally to mesopleural pit. Sculpture of postacetabular patch: densely punctate. Sculpture of anterior mesepisternum: smooth with punctures. Mesopleural epicoxal sulcus: comprised of cells anteriorly. Mesopleural carina: weakly indicated ventrally. Speculum: transversely striate. Paracoxal sulcus in ventral half of metapleuron: indicated by a line of distinct foveae. Length of intercoxal space: exceeding length of mesocoxae. Anteroventral extension of metapleuron: short and truncated. Line of pits along metapleural carina: present. Setation of metapleuron: absent (Fig. 8). Metapostnotum: invaginated at edges of metascutellum and separating metanotum from propodeum. Metasomal depression of propodeum: with striae radiating from propodeal foramen. Length of postmarginal vein: about 1.8 × as long as stigmal vein. Length of metabasitarsus: longer than combined length of metatarsomeres 2–5 (Fig. 9).
Metasoma. Sublateral setae on T 1: absent. Setation of laterotergite 1: absent. Sculpture of T 2 posterior to antecostal sulcus: distinctly striate in basal half, striae longer laterally, smooth in apical half. Length of T 3 – T 6: subequal to length of T 2 (Fig. 10).
Male. Body length: 1.82–2.11 mm (n = 5). Color of antenna: scape and flagellum yellow (Fig. 12).
Etymology.
This species is named in honor of Adriana Trevizoli Salomão, the collector. The epithet is treated as a noun in the genitive case.
Distribution.
Brazil (São Paulo state) (Fig. 11).
Host.
The eggs of Phloea subquadrata Spinola, 1837 (Hemiptera, Phloeidae).
Material examined.
Holotype. Brazil • ♀; São Paulo, Jundiaí; 23°14'04"S, 46°55'28"W, 900 m. a. s. l.; 02.xi.2011; Ex Phloea subquadrata eggs on Plinia cauliflora; A. T. Salomão; MZUSP 133071.
Paratypes. Brazil • 7 ♀ ♂, same data as for holotype; 5 ♀, 1 ♂ MZUSP 133072 –133077, 1 ♀ OSUC 782300.
Remarks.
In the key to the New World species of the flavipes group (Johnson 1987), T. adrianae keys to couplet 6, as the scutellum has no median carina. The key of Johnson (1987) is modified to accommodate T. adrianae:
Another species of the group with a more elongate and depressed habitus is T. decumbens Johnson. However, besides the differences mentioned above in diagnosis, the two species would be distinguished immediately in the first couplet of Johnson (1987) key for the species of the group: while a distinct median longitudinal carina is present in the mesoscutellum of T. decumbens, such a carina is absent in T. adrianae. There are other differences; in T. adrianae the antennae of the female are almost entirely brown, mesonotum nearly flat, with posterior two thirds of mesoscutum and mesoscutellum in the same plane, mesonotum punctate, with well-defined setigerous punctures irregularly distributed and with interspaces smooth, and the coxae yellow. In T. decumbens the female antennae are abruptly bicolored, with A 1 – A 7 yellow and A 7 – A 11 dark brown, mesonotum convex, the mesoscutum with coriaceous to reticulate microsculpture throughout, and the coxae dark.
Trissolcus adrianae is the first species of Scelionidae associated with the family Phloeidae (Hemiptera: Pentatomoidea) and the first report of parasitism of Phloeidae eggs as well. Phloeidae is a small family that contains only 2 genera and 3 species endemic to the Neotropical region (Bernardes et al. 2005; López and Schwertner 2024). Phloea subquadrata eggs are laid in clusters on tree bark, forming an egg mass which is completely covered by the guarding female’s flattened body (Magalhães 1909). Similar guarding behavior in the pentatomid Antiteuchus tripterus (Fabricius) has been associated with defense against egg parasitism by the telenomines Trissolcus bodkini Crawford and Phanuropsis semiflaviventris Girault (Eberhard 1975). The remarkably flattened body of T. adrianae may be an adaptation so that the female wasp can have access to the eggs. Another possibility is that T. adrianae may be phoretic on the adult of its host. The flattened body and elongate hind basitarsi are features found in other phoretic species of Trissolcus as well as the mantid egg parasitoids of the genus Mantibaria Kirby (Hymenoptera: Scelionidae).
description: Published as part of Costa, Valmir A., Johnson, Norman, Salomão, Adriana, Vasconcellos-Neto, João, Wengrat, Ana & Schoeninger, Karine, 2025, A remarkable new species of Trissolcus Ashmead (Hymenoptera, Scelionidae), parasitoid of eggs of Phloea subquadrata (Hemiptera, Phloeidae) in Brazil, pp. 405-417 in Journal of Hymenoptera Research 98 on pages 405-417, DOI: 10.3897/jhr.98.144215