Olixon caju Celante, Martins & Bulbol 2025, sp. nov.
Creators: name: Celante, Gabriel Luiz
name: Carvalho, Adhan Gabriel
name: Martins, André Luis
name: Bulbol, Mayara Medeiros
name: Brito, Amaury Soares De
name: Teodoro, Adenir Vieira
name: Jahyny, Benoit Jean Bernard
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Rhopalosomatidae
Olixon
Olixon caju

description: Olixon caju Celante, Martins & Bulbol, sp. nov.
http://zoobank.org/ urn:lsid:zoobank.org:act: 62DEC50D-BD40-4359-88C2-C770F1CADDA5
(Figs 2–7)
Type material. HOLOTYPE ♂ with the following labels:“ Brasil – SE, Itaporanga d'Ajuda \Col. Brito,A. \ 21.IX.2017 \ 11.1213S, 37.1903W \ MFCE014404 ” “ RPPN do caju, coletado em área de vegetação arbustiva, armadilha pitfall ” (MFCE). ALLOTYPE 1♀, with following labels: “ Brasil – SE, Itaporanga d'Ajuda \ Col. Brito, A. \ 21.IX.2017 \ 11.1185S, 37.1852W \ MFCE014403 ” “ RPPN do caju, coletado em área de floresta secundária, armadilha pitfall ” (♀) (MFCE). PARATYPES 2♂; with following labels: “ Brasil – SE, Itaporanga d'Ajuda \ Col. Brito, A. \ 21.VI.2018 \ 11.1185S, 37.1852W \ MFCE014405 ” “ RPPN do caju, coletado em área de floresta secundária, armadilha pitfall ” (♂) (MFCE); “ Brasil – SE, Itaporanga d'Ajuda \ Col. Brito, A. \ 29.I.2018 \ 11.1213S, 37.1903W \ MFCE014406 ” “ RPPN do caju, coletado em área de vegetação arbustiva, armadilha pitfall ” (♂) (INPA).
Diagnose. The new species differs from other species of the genus due to the following combination of characters: ocelli present; malar sulcus between the eye and the base of the mandible (Figs 3A, 6A); brachypterous, but with membrane broadly expanded (Figs 2A, B, 3B, 5A, B, 6E); female penultimate mesotarsomeres with asymmetrical lobes (Fig. 6C); female penultimate metatarsomeres with the distal region wider than the proximal region and symmetrical lobes (Fig. 6D); T 1 with a transverse carina and without median sulcus posterior to transverse carina (Figs 3B, 6B); male genitalia with two preapical processes.
Description. Male. Body length 4.50 mm [4.5–5.00 mm] Colour. Predominantly brown, except antennae, legs and part of metasoma pale brown. Head. Vertex with many evenly distributed short setae (Fig. 3A); frons surface without deep punctures; malar sulcus present and complete (Fig. 3A); posterior ocelli and anterior ocellus present, reduced; ocular sulcus without pubescence; OOD 1.33× IOD [OOD 1.10 –1.33× IOD]; clypeus pubescence, dense and complete; eye 1.75× [1.75 –1.84×] as long as wide, temple length 0.12× [0.12 –0.14×] and malar space 0.43× [0.36 –0.43×] as long as eye length; clypeus 2.55× [2.33 –2.73×] as wide as high; flagellomeres, without conspicuous apical setae; F1 1.80× [1.80 –2.22×] as long as wide, 1.64× [, 1.64 –1.90×] as long as pedicel, and 0.55× [0.55 –0.59×] as long as F2. Mesosoma. PnI 1.20 [1.20–1.33]; tegulae separated from each other by 2.63× [2.40 –2.75×] the width of one tegula; PpI 1.06 [1.06 –1.19]; propodeal spiracles situated closer to posterior than to anterior propodeal margin; each posterolateral propodeal process triangular and well developed (Fig. 3B); convex carina with a small longitudinal ridge in the central region between the two posterolateral propodeal process (Fig. 3B); metapleural sulcus incomplete. Legs. Profemur 1.95× [1.95 –2.00×] as long as wide; metafemur 5.05× [4.50 – 5.05×] as long as wide; outer hind tibial spur present, inner hind tibial spur 0.55× [0.54 –0.56×] as long as basitarsus; lobes of the penultimate mesotarsomere asymmetric (Fig. 3C); lobes of the penultimate metatarsomere symmetric (Fig. 3D); penultimate metatarsomere with the distal and proximal region of approximately the same width (Fig. 3D). Wings. Brachypterous, forewing with membrane expanded and tubular longitudinal vein along costal margin and two longitudinal veins, at rest reaching T1 (Fig. 3B); hindwing reduced to short stub. Metasoma. Dorsal surface of T1 with transverse carina, without median sulcus posterior to transverse carina (Fig. 3B). Genitalia. Paramere (Fig. 4A): base, 1,2× longer than wide; paramere spine elongated and acute apically, but curved dorsally; cuspis and digitus (Fig. 4B): linked by the membrane that unites them to the paramere, membrane 2.4× longer than wide covered with cylindrical bristles and elongated cuspis; digitus robust with rounded apex, both slightly curved dorsally, apexes punctuated with bristles and more sclerotized than the rest of the volsella; penis valve (Fig. 4C): laterally flattened, elongated and with a rounded apex, ventral margin with two preapical processes, the first in the form of a column with the apex wider than the base and the second with a triangular shape inclined anteriorly.
Female. Body length 5.75 mm. Colour. Predominantly brown, except antenna, legs and part of metasoma pale brown. Head. Vertex with many evenly distributed short setae (Fig. 6A); frons surface without deep punctures; malar sulcus present and complete (Fig. 6A); posterior ocelli and anterior ocellus present, reduced; ocular sulcus without pubescence; OOD 1.33× IOD; clypeus pubescence, dense and complete; eye 2.09× as long as wide, temple length 0.17× and malar space 0.48× as long as eye length; Clypeus 2.4× as wide as high; flagellomeres without conspicuous apical setae; F1 1.80× as long as wide, 1.5× as long as pedicel, and 0.53× as long as F2. Mesosoma. PnI 1.67; tegulae separated by 2.0× the width of one tegula; PpI 1.27; propodeal spiracles situated closer to posterior than to anterior propodeal margin; each posterolateral propodeal process long; convex carina with a small longitudinal ridge in the central region between the two posterolateral propodeal process (Fig. 6B); triangular and well-developed posterolateral propodeal process (Fig. 6B); metapleural sulcus incomplete. Legs. Profemur 1.67× as long as wide; metafemur 3.42× as long as wide; outer hind tibial spur present, inner hind penultimate metatarsomere symmetric (Fig. 6D); penultimate metatarsomere with the distal region wider than the proximal region (Fig. 6D). Wings. Brachypterous, forewing with membrane expanded and tubular longitudinal vein along costal margin and two longitudinal veins, at rest reaching T1, but shorter than male forewing (Fig. 6E); hindwing reduced to short stub. Metasoma. Dorsal surface of T1 with transverse carina, without median sulcus posterior to transverse carina (Fig. 6B); stridulatory organ present on T3 (Fig. 5B).
Etymology. The name of the new species is a direct reference to cashew (Caju, in Portuguese), a name given to the peduncle (pseudofruit) attached to the “nut” (fruit) of the cashew tree (Anacardium occidentale L.), a plant typical of northeastern Brazil with high socioeconomic importance for the region. This fruit also gave its name to the natural reserve (RPPN do Caju) where the new species was found.
Distribution. Brazil, Sergipe state (Fig. 7).
Biological aspects. Based on what we know about the species’ biological aspects, it seems to prefer environments with a greater abundance of trees and shrubs, as well as denser leaf litter. These factors contribute to a lower average temperature and higher relative humidity in these places (Brito et al. 2023), where its hosts probably live.
Remarks. Holotype (MFCE14404): right antenna broken, flagellomeres 7 to 11 glued in a triangle next to the specimen. The paramere, volsella, penis valve, and the sterna 6, 7 and subgenital plate, removed during the dissection of the genitalia, are stored in a microtube filled with glycerine and pinned next to the specimen.
description: Published as part of Celante, Gabriel Luiz, Carvalho, Adhan Gabriel, Martins, André Luis, Bulbol, Mayara Medeiros, Brito, Amaury Soares De, Teodoro, Adenir Vieira & Jahyny, Benoit Jean Bernard, 2025, Contributions to the knowledge of Olixon Cameron, 1887 (Hymenoptera, Rhopalosomatidae): a new species and new records of the genus for northeastern Brazil, pp. 549-562 in Zootaxa 5570 (3) on pages 551-556, DOI: 10.11646/zootaxa.5570.3.6, http://zenodo.org/record/14745431