Coriotela lasallei Burks & Heraty, 2020

Burks, Roger A. & Heraty, John M., 2020, First described fossil representatives of the parasitoid wasp taxa Asaphesinae n. n. and Eunotinae (Hymenoptera: Chalcidoidea: Pteromalidae sensu lato) from Eocene Baltic amber, Journal of Natural History 54 (9), pp. 801-812 : 805-806

Coriotela lasallei Burks & Heraty n. sp.

( Figure 1 (a – c))

http://www.zoobank.org/ urn:lsid:zoobank.org:act:0F193F45-CE1B-4A61-A32F-BAE76F3A5900

Description. Female: Length 2.13 mm (n = 1).

Head. Scape not reaching level of median ocellus; pedicel subequal to combined length of F1 – F3; flagellum with 1 anellus, 7 funiculars, and 4 clavomeres (including terminal button); anellus transverse, with short setae; funiculars progressively becoming broader, but not longer, apically; F2 about as long as broad; clava symmetrical. [mandibles closed and poorly visible, therefore teeth not counted]

Head with coriaceous to imbricate sculpture, with short setae; interantennal prominence present, acute dorsally. Toruli separated by about 1 torular diameter. Eyes subparallel, with extremely small setae that are hardly visible at 50 × magnification. Clypeus short and broad. Labrum with frontal surface recessed, apically slightly concave. Malar sulcus present. Vertex rounded.

Mesosoma with short setae; dorsum coriaceous to imbricate. Pronotum long, broad, smoothly rounded anteriorly, uniformly sculptured. Upper mesepimeron slightly raised, broad recessed area partially crossing mesepimeron at transepimeral line; anterior margin of metapleural lateral area slightly overlapping mesepimeron. Fore wing with postmarginal vein slightly curved 1.82 × stigmal vein length (including stigma), 1.4 × marginal vein length; uncus long. Propodeum coarsely sculptured, with carinae near spiracle.

Metasoma length 1.6 × metasoma width, 1.4 × mesosoma length. Gastral terga of similar length, but Gt 3 slightly shorter than the others. Hypopygium short, reaching only to Gt 2.

Material examined

Holotype. Baltic amber inclusion: Eocene, Jens-Wilhelm Janzen coll., 2007 AMNH Ba-JWJ285 . Photo also in Janzen 2002 (Figure 311). [1F #, AMNH: UCRCENT00237910 ]. Deposited in AMNH.

Etymology. Named after John La Salle, who first introduced me (RAB) to the excitement of chalcidoid fossils.

Discussion. Coriotela is classified in Asaphesinae because of shared features with Hyperimerus and to some undescribed Neotropical genera, including antenna position and flagellomere shape and count (Shender et al. Figure 14), pronotum shape (Shender et al. Figure 19), and fore wing venation (Shender et al. Figure 21). Because Asaphesinae is not yet defined phylogenetically, the key features used for this placement are likely a mix of plesiomorphies and synapomorphies. Some defining features of the subfamily are relatively rare across Chalcidoidea , and therefore should be investigated as potential synapomorphies of the subfamily, including: metasomal petiole short but with strong sculpture ( Figure 1 (b)), gaster strongly sclerotised and rigid, fore wing venation with a short marginal vein relative to the stigmal and postmarginal veins, parastigma with a constriction ( Figure 1 (c): constriction). Other defining features of the group are more likely plesiomorphic or only very locally informative, but serve to eliminate some other taxa from consideration: antenna with 12 flagellomeres, occipital carina present, pronotum with a relatively long but anteriorly rounded collar, notauli complete, frenal groove indicated.

A suite of similar taxa in Pteromalidae s. l. can be eliminated from consideration for placement of C. lasallei as follows: Pteromalinae either exhibit a demarcation between the pronotal collar and pronotal neck, or the pronotum consists only of an essentially vertical neck, and pteromalines do not have all the other key features of C. lasallei in combination. The lack of absolute morphological distinction between Pteromalinae and other subfamilies of Pteromalidae s. l. has been discussed elsewhere ( Graham 1969; Bouček 1988), but molecular data support a monophyletic Pteromalinae , inclusive of some non-pollinator fig wasps, that is separate from most other subfamilies of Pteromalidae sensu lato ( Heraty et al. 2013). The genera of Pteromalinae most similar to C. lasallei and other Asaphesinae include Coruna Walker , Oricoruna Bouček , Sphegipterosema Girault , and Yanchepia Bouček. However , each of these genera lacks key features mentioned in the diagnosis of C. lasallei and instead possess gestalt features that place them in particular subgroups of Pteromalinae ( Graham 1969; Bouček 1988; Bouček and Rasplus 1991; Bouček and Heydon 1997).

A few subgroups of Pteromalidae s. l. are somewhat similar to C. lasallei , and are discussed here to help explain its subfamily placement. Austrosystasinae differs from all Asaphesinae in features of gestalt: a more arched and stout body, and a much larger metacoxa ( Bouček 1988, figure 550). Diparinae usually possess an occipital carina, but other typically diparine features such as the cercal brush ( Desjardins 2007, figure 17) and gestalt features of metacoxal sculpture and of the fore wing are absent from C. lasallei . Herbertiinae are part of a set of pteromalid taxa that differ by having fewer than 12 antennal flagellomeres. Keiraninae are similar to C. lasallei , but have a more distinct pronotal collar that is set off from the pronotal neck by a stronger change in curvature ( Bouček 1988, figure 475). Distinction of Asaphesinae from Keiraninae, when limited to features typically visible on an amber fossil, relies on vague gestalt features. However, preliminary genetic data (Heraty et al. unpublished) support separation of extant species of these two taxa into widely separated clades in the superfamily phylogeny. Melanosomellini (in Ormocerinae ) contains a few genera with an occipital carina, but these have a smaller axillula and a strong mesoscutellar rim, and they have a broader, less sculptured petiole (e.g. Bouček and Heydon 1997, figure 80). Parasaphodinae differ in having strongly advanced axillae ( Bouček 1988, figure 629).

Within Asaphesinae, C. lasallei is distinguished by a combination of features mentioned in the diagnosis of the genus. Asaphes differs chiefly in having two or more basal flagellomeres lacking multiporous plate sensilla (= anelli) and toruli situated very near the mouth margin ( Bouček and Rasplus 1991; Bouček and Heydon 1997, figure 84; Gibson and Vikberg 1998). Ausasaphes Bouček possesses a dorsally indistinct frenal groove and a longer petiole ( Bouček 1988, figure 631). Enoggera Girault possesses a very differently shaped head, mesosoma, and metasoma, and also differs in having more anelliform basal flagellomeres and a much larger Gt 1 ( Bouček 1988). Hyperimerus Girault differs in that its prepectus and Gt 1 basally are strongly setose ( Gibson and Vikberg 1998; Schender et al. 2014 figures 11 – 12). The chiefly coriaceous sculpture of Coriotela is also distinctive within the subfamily, present mainly in some undescribed Neotropical taxa (Burks unpub.).

Figures

Figure 1. (a–c) Coriotela lasallei n. gen., n. sp. holotype female: (a) Body, dorso-lateral; (b) Head, mesosoma, and anterior part of metasomal, lateral, frl = frenal groove, occ = occipital carina. (c) Fore wing, clv = clava, clavomeres numbered. (d,e) Butiokeras costae n. gen., n. sp. holotype male: (d) Body, dorso-lateral; (e) Body, ventro-lateral.