Dimophora? wickhami (Cockerell, 1919) Spasojevic & Broad & Klopfstein, 2022

Spasojevic, Tamara, Broad, Gavin R. & Klopfstein, Seraina, 2022, Revision of 18 ichneumonid fossil species (Hymenoptera, Ichneumonidae) highlights the need for open nomenclature in palaeontology, Fossil Record 25 (1), pp. 187-212 : 187

Dimophora? wickhami (Cockerell, 1919) comb. nov.

Fig. 4

* Theronia wickhami Cockerell, 1919

Material.

Photograph examined of the holotype (part, PALE-3915 and counterpart, #UCM8604), obtained from the MCZ and UCM, respectively.

Stratum.

Wilson Ranch, Florissant shales, Colorado, USA. Late Eocene (Chadronian), 37.2-33.9 My.

Description.

Female. Rather well-preserved fossil. Part with dorsal and posterior aspect of head, antennae almost complete, mesosoma including propodeum and details of propodeal carination, weak impressions of fore wings with only few veins visible, incomplete hind legs, and dorsal aspect of metasoma with ovipositor and ovipositor sheaths. Counterpart with ventral aspect of head with antennae showing flagellomeres, mesosoma, weakly but almost completely preserved impressions of fore wings, partial mid and almost complete hind legs, and ventral aspect of metasoma with ovipositor sheaths. Body length 8.5 mm.

Dark brown on head, mesosoma and first metasomal segment, lower part of face possibly lighter coloured (but could be artefactual), antennae lighter brown, wing venation very light, legs and metasoma from T2 or T3 orange.

Head with parallel-sided inner eye margins; mandibles with two teeth; clypeal sulcus weakly developed; occipital carina strong and probably complete and evenly rounded dorsally. Antennae 5.4 mm, with scape a bit longer than wide and pedicel short; with about 31 flagellomeres, these transverse except for most basal ones. Mesosoma showing deep median sternal groove, probably complete epicnemial and complete posterior transverse carina of mesosternum. Metapleuron with submetapleural carinae shown as two longitudinal lines; propodeum with complete propodeal carination. Fore wing 5.9 mm, with large and slightly oblique areolet, vein 2m-cu meeting M close to its outer corner (4M very short), number of bullae unclear; 1cu-a meeting M + Cu opposite of 1M and inclivous; 3Cu about as long as 2cu-a; cell 2R1 2.6 × longer than wide. Legs rather slender; hind femur 3.6 ×, hind tibia 6.2 × longer than wide, without ventral tooth. Metasoma slender, apical segments compressed; T1 petiolate, narrow at base and expanded from about mid-length; S1 reaching to about 0.65 of length of T1, probably with laterotergites parallel and not meeting ventrally at midline; T2 about 2.2 × longer than basally wide, with narrow laterotergite visible; following tergites transverse; hypopygium inconspicuous. Ovipositor 1.5 mm, around 1.7 × as long as hind tibia, straight, enclosed by sheaths.

Interpretation.

The petiolate T1 excludes the subfamily Pimplinae and thus the genus Theronia , and the compressed metasoma and complete posterior transverse carina of mesosternum carina point to either Campopleginae or Cremastinae . The clypeus separated from the lower face by a groove and the rather stout fore wing cell 1M+1R1 point to the latter. Within Cremastinae , the large areolet is reminiscent of Dimophora , even though it is slightly oblique. A recent revision of the Australian members of the genus (Klopfstein 2016) expanded the generic definition to also include larger representatives, with fore wing lengths of up to 7.1 mm found. As the areolet does not entirely match extant Dimophora and characters excluding some other genera in the subfamily are not visible, we tentatively place the fossil in this genus. It can be distinguished from all extant representatives of the genus by fore wing vein 2m-cu originating close to the distal end of the areolet, from D. antiqua ( Brues 1910; also from the Florissant shales) by the larger areolet and less stout fore wing, from D. fumipennis (Theobald 1937; Oligocene of Aix-en-Provence) by the hyaline wings and longer ovipositor, and from the here revised D.? longicornis by the much shorter ovipositor, more slender pterostigma and different coloration.

Metopiinae Förster, 1869

Acerataspis ? (Uchida, 1934)

Figures

Figure 4. Dimophora? wickhami (Cockerell, 1919) comb. nov. A. Photograph of the counterpart of the holotype obtained from the UCM; B. Photograph of the propodeum from the part of the holotype obtained from the MCZ; C. Our interpretative drawing of the counterpart; D. our interpretative drawing of the propodeum of the part. Thicker lines indicate outlines of body structures, thinner lines show characters inside these outlines, and dotted lines represent uncertain interpretations.