Rhopalosoma Cresson, 1865:58

Lohrmann, Volker, Ohl, Michael, Michalik, Peter, Pitts, James P., Jeanneau, Laurent & Perrichot, Vincent, 2019, Notes on rhopalosomatid wasps of Dominican and Mexican amber (Hymenoptera: Rhopalosomatidae) with a description of the first fossil species of Rhopalosoma Cresson, 1865, Fossil Record 22 (1), pp. 31-44 : 34-35

Rhopalosoma Cresson, 1865:58 . Type species: Rhopalosoma poeyi Cresson, 1865 , by monotypy.

Sibyllina Westwood, 1868:329 . Type species: Sibyllina aenigmatica Westwood, 1868 , by monotypy. Synonomy by Westwood, 1874: 130.

Diagnosis

Among extant and fossil rhopalosomatids, species of Rhopalosoma are characterized by the following character combination. The wings are fully developed (brachypterous in Olixon ); the occipital carina is present (absent in Liosphex ); the apical section of the fore wing cubitus (Cu 2 in Fig. 4 ) is at least slightly sinuate (arched, but indented at the level of junction with CuA in Paniscomima , and almost straight in Eorhopalosoma ); female pretarsal claws have a preapical tooth (as in Figs. 4b , 6c ); female tarsomeres II–IV have apicolateral tarsal fenestrae ( Fig. 6b ); and the second preapical process of the male penis valve is narrow to broad, distad from the head of the penis valve, and is not overlapped at its apex by the third preapical process ( Fig. 1d ; broadly triangular, near head of penis valve, and overlapped in Paniscomima ).

(Males and females of the family can be differentiated by the number of flagellomeres – males have 11, and females have 10, by the number of visible metasomal tergites – males have 7, and females have 6, and by the form of tarsomeres II–IV – cylindrical for males and flattened for females. For a more detailed morphological description of the genus and all extant species, including a species-level identification key, the family revision of Townes (1977), should be consulted.)

V. Lohrmann et al.: Notes on rhopalosomatid wasps of Dominican and Mexican amber 35

Distribution

Distribution is predominantly in the tropics and subtropics of the Americas (eastern United States to southern Brazil and northern Argentina), including some of the Caribbean countries ( Bahamas, Cayman Island, Cuba, and Haiti; Townes, 1977).

Biology

As it concerns the extant fauna, Rhopalosoma nearcticum Brues, 1943 , has been associated with species of trigonidiine and hapithine genera ( Insecta: Orthoptera ), i.e., Anaxipha Saussure, 1874 , Hapithus Uhler, 1864 , and Orocharis Uhler, 1864 ( Hood, 1913 – misidentified as R. poeyi Cresson, 1865 ; Gurney, 1953; Townes, 1977; Blaschke et al., unpublished results; see also Fig. 1a–b ). For the remaining 16 extant species in the genus, however, no data have been published to date on their host–parasite relationships.

Figures

Figure 1. Rhopalosomatidae spp. (a–b) Recent rhopalosomatid larva (last instar, shortly before leaving the host, putatively Rhopalosoma nearcticum Brues) parasitizing a hapithine cricket (Grylloidea). Photographed at Jones Nature Preserve, Rappahannock County, Virginia, USA, on 15 September 2017. Photos: Judy Gallagher, CC-BY-2.0, originally posted to Flickr. (c–d) Rhopalosoma nearcticum Brues, male. (c) Photographed in Mobile (Dog River), Mobile County, Alabama, USA, on 4 July 2011. Photo: Robert Lord Zimlich, originally posted to BugGuide. (d) Penis valve in lateral view. Abbreviations: ant – anterior, hpv – head of penis valve, pap1 – first preapical process, pap2 – second preapical process, pap3 – third preapical process, and pos – posterior.

Figure 4. Rhopalosoma hispaniola sp. nov.: female, holotype, MB.I 5915, Miocene Dominican amber. (a) Overview. (b) Detail of the head in dorsal view. (c) Detail of the tarsal claws. (d) Distal section of mid tibia with tibial spurs. (e–f) Details of the right fore wing. Abbreviations used in (b) and (c): en – eye notch, lo – lateral ocellus, mo – median ocellus, oc – occipital carina, tc – tarsal claw, t5 – tarsomere 5, and pat – preapical tooth.

Figure 6. Rhopalosoma sp.: female, MB.I 6549, Miocene Mexican amber. (a) Overview. (b) Left hind tarsus. (c) Pretarsus with claws. (d– e) Details of left fore wing. (f) Details of right hind wing. Abbreviations used in (b) and (c): pat – preapical tooth, tc – tarsal claw, tf – tarsal fenestrae, t1 – tarsomere 1, t2 – tarsomere 2, t3 – tarsomere 3, t4 – tarsomere 4, and t5 – tarsomere 5.