Cyrtolabulus van der Vecht, 1969

Selis, Marco, 2024, Revision of the genus Cyrtolabulus van der Vecht in Madagascar (Hymenoptera: Vespidae: Eumeninae), Zootaxa 5406 (1), pp. 66-86 : 67

Genus Cyrtolabulus van der Vecht, 1969

Cyrtolabulus van der Vecht 1969: 1 , replacement name for Cyrtolabus van der Vecht, 1963 , non Voss, 1925. Type species: Cyrtolabus suavis van der Vecht, 1963 , by original designation as type species of Cyrtolabus van der Vecht. Cyrtolabus van der Vecht 1963: 11 , genus. Junior homonym of Cyrtolabus Voss, 1925 ( Coleoptera ). Type species: Cyrtolabus suavis van der Vecht, 1963 , by original designation.

Diagnosis. Belonging to the group of Eumeninae “Odynerini” with apically lamellate T2 and basally obtuse second submarginal cell, distinguished by the following combination of characters: tegula small or broadly rounded but not reaching metanotum posteriorly, second submarginal cell not petiolate, propodeum not markedly elongate, often with a distinct horizontal face behind metanotum, propodeal valvula elongate and rectangular, metasoma petiolate, T1 subcylindrical with weakly diverging sides in dorsal view, not abruptly expanding posteriorly.

Differential diagnosis. Among the Malagasy genera of Eumeninae , Cyrtolabulus can only be confused with the genus Cyrteumenes Giordani Soika, 1991 , established by Giordani Soika (1991: 80) to include the Malagasy species of “ Labus ” characterized by the following combination of characters: oval mesosoma not much longer than wide, sides of pronotum anteriorly converging, pronotal humeri rounded with curved carina, mesepisternum lacking epicnemial carina, metanotum oblique and lacking transverse carina, propodeum entirely rounded and lacking horizontal face behind metanotum, submarginal carina produced in large lobes above valvulae, tegulae small and almost circular, T1 pyriform with strongly expanded apical half, and T2 with apical lamella. As already stated by Giordani Soika, Cyrteumenes is closely related to Cyrtolabulus , and some of the characters he proposed as diagnostic are in fact observed in some Malagasy species of the latter, such as the small rounded tegula in C. flavorufus , and the rounded propodeum without a horizontal face in C. flavorufus and C. madli . On the other hand, Cyrteumenes differs from all the Malagasy species of Cyrtolabulus by shape of mesosoma, evenly rounded metanotum, large lobes of submarginal carina, and shape of T1. Outside the Malagasy fauna, the Afrotropical species of Cyrtolabulus are generally characterized by having a subcylindrical and not apically expanded T1, like the Malagasy species of the genus, while some species belonging to the Palearctic fauna [e.g. C. exiguus (de Saussure) , C. gracilis (Kohl) , C. minoicus Gusenleitner , C. syriacus (Giordani Soika) , C. transversus Giordani Soika ] have a conical or pyriform T1, but never strongly expanded as in Cyrteumenes . Furthermore, both Afrotropical and Palearctic species of Cyrtolabulus have the metanotum always carinate, more markedly in species that have a sloping propodeum, unlike Cyrteumenes which have always regularly rounded metanotum. In addition to the differences already observed by Giordani Soika (1991) and discussed above, another constant difference between Cyrtolabulus and Cyrteumenes lies in the shape of S1, which in Cyrtolabulus is reduced to a semicircular apical sclerite due to the fusion of the lateral margins of T1, while in Cyrteumenes it is subtriangular and elongated with an evident basal stem that separates the margins of T1. Given the constant and well-marked differences discussed above, Cyrteumenes is here maintained as a separate genus, although clearly related to Cyrtolabulus , and is therefore not included in the current revision.