Paleogenia Waichert and Pitts, 2016

Rodriguez, Juanita, Waichert, Cecilia, Von Dohlen, Carol D., Jr., George Poinar & Pitts, James P., 2016, Eocene and not Cretaceous origin of spider wasps: Fossil evidence from amber, Acta Palaeontologica Polonica 61 (1), pp. 89-96 : 92-93

Genus Paleogenia Waichert and Pitts nov.

Etymology: From Greek paleo, ancient; and Agenia , a proper name widely used for Pepsinae taxa. The gender is feminine.

Type species: Paleogenia wahisi Waichert and Pitts sp. nov., monotypic.

Diagnosis.—Antennal segments short; propodeum smooth, with a lateral carina; tibia with apical spine-like setae short, regular; fore, mid and hind tibia not spinose; first metasomal segment with a lateral carina; wing hyaline; forewing with cells short, 2M cell without an inflection on the base of Cu vein; 1Rs and 2Rs about the same size; 1 R 1 and 1M about the same size; 1M 1/3 as wide as long; 2m-cu vein arising on the Cu more than half the distance from the base of the 2M cell to the outer wing margin.

Remarks.—This genus is morphologically similar to the cosmopolitan genus Minagenia Banks, 1934 . These genera resemble each other by having cells 1Rs and 2Rs small and about the same size, a short clypeus, straight stinger, and bulging eyes. However, Paleogenia gen. nov. differs from Minagenia by having dentate claws, short antennal segments, and subgenital plate S6 not laterally compressed. Additionally, the 2 R 1 cell in Paleogenia is large, with length 2.5× its width, and it almost touches the apical margin of the forewing. Usually in pompilids, the 2 R 1 cell ends somewhere in the anterior margin of the wing, never the apical margin.

Paleogenia is assigned to the subfamily Pepsinae due to the absence of an inflection at the base of the Cu vein in 2M cell and the presence of regular, apical spine-like setae on the tibia. Additionally, Paleogenia gen. nov. has the metasomal sternum 2 with a distinct sharp transverse groove. This genus is placed in the tribe Pepsini , because it has a defined carina on the first metasomal segment. This is the only genus in the tribe with short antennal segments. The wing venation also resembles that of Poecilagenia and Nipponodipogon Ishikawa, 1965 species. However, Poecilagenia has an elongated body and punctuated integument that differs from the short body and polished integument shown on P. wahisi Waichert and Pitts sp. nov. Besides, P. wahisi has a transversal carina on the first metasomal segment, which is absent on Poecilagenia species. Paleogenia cannot be placed on Nipponodipogon , because it has two apical mandibular teeth, whereas in Nipponodipogon three teeth are present. Moreover, Paleogenia has hyaline wings, lacking basal or apical fascia on forewing, as present on Nipponodipogon .

Remarks.—Balticamberdepositshavebeenobtainedformore than 100 years, and their age is controversial. Microfaunistic dating of the deposits containing the largest amount of amber suggest they are from the Priabonian, Eocene (37.7 Ma) ( Kaplan et al. 1977), whereas radiometrically dated glauconite dates them as Lutetian, Eocene (47.0 to 44.1 Ma) ( Ritzkowski 1997). Perkovsky et al. (2007) considered the Ritzkowski (1997) data insufficient to disprove Kaplan et al. (1977), because the former was based on two samples and the latter on seven samples. Novel data indicate that the age of Baltic Amber can be narrowed to 34–38 Ma ( Aleksandrova and Zaporozhets 2008; Kosmowska-Ceranowicz 2012).

Stratigraphic and geographic range.—Eocene Baltic amber of the Kaliningrad region of Russia.