Orasema bakeri
Creators: name: Baker, Austin J.
name: Heraty, John M.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Eucharitidae
Orasema
Orasema bakeri

description: Orasema bakeri species group
(Figs 11–16)
Established by Heraty (2000).
Diagnosis. Recognized by the following combination of characters: prepectus with anterior margin lacking a carina and gradually sloping under margin of pronotum (Fig. 13C), female petiole usually short (PTL:PTW <1.5), face and mesoscutal midlobe reticulate (Fig. 13B, F), antenna with 7 funiculars (Fig. 13D, E), and labrum with 4 digits (Fig. 12B).
This group can be difficult to distinguish from the cockerelli group, with the anterior edge of the prepectus often the only consistent difference between members of the groups.
Description. Female. Length 2.2–3.5 mm. Color. Antennal flagellum brown. Mandible brown. Coxae brown with iridescence; femora mostly brown, tips pale. Gaster brown with iridescence. Head. Face reticulate; longitudinal groove between eye and torulus absent; malar depression weakly impressed adjacent to mouth; clypeus weakly sculptured; anterior tentorial pit strongly impressed. Labrum with 4 digits. Mandibular formula 3:2. Occiput imbricate, emarginate in dorsal view; temples present, rounded. Scape not reaching median ocellus. Flagellum with 7 funiculars; anellus disc-shaped; funiculars subequal in length distally, equal in width; clava subovate. Mesosoma. Mesoscutal midlobe, frenum, propodeal disc, and propleuron reticulate. Prepectus reticulate. Mesepisternum reticulate, broadly rounded anterior to mid coxa. Hind coxa reticulate. Hind wing costal cell with a broad bare area.
Metasoma. Antecostal sulcus foveate; acrosternite posteriorly rounded; apical setae of hypopygium with several long hairs on each side of the midline. First (ventral) valvula with 6–8 small, narrowly separated teeth.
Male. Length 1.7–3.0 mm. Scape brown with iridescence; flagellum with 7 funiculars, anellus disc-shaped. Femora mostly brown, tips pale.
Phylogenetics. Four species in the Orasema bakeri group have been molecularly sampled for Sanger-sequenced genes: O. texana, O. bakeri, O. taii, and O. dubitata; only O. bakeri has been sequenced with AHE. Specimens of O. bakeri and O. dubitata from Baker et al. (2020) were misidentified: “ Orasema _nr_bakeri_ USA:AZ_AE_D4097” is O. bakeri (UCRCENT00411576), whereas “ Orasema _bakeri_ USA:AZ_D3720” and “ Orasema _bakeri_ USA: FL_D3153” are Orasema dubitata (UCRCENT00352479, UCRCENT00292550, respectively). The bakeri-taiidubitata clade consists of the most difficult species to delimit in the bakeri group. Orasema dubitata was first recognized as distinct from O. bakeri by a number of differences in Sanger sequenced genes (18S rDNA has one nucleotide difference; 28S D2 rDNA two differences; 28S D3–5 rDNA four differences; COI-BC (cytochrome oxidase I barcoding) mtDNA six amino acid changes and at least 15 unambiguous nucleotide differences; COI-NJ (cytochrome oxidase I NJ) mtDNA has one amino acid change and three unambiguous nucleotide differences), and O. taii has only a small number of differences from O. dubitata (28S D2 has one difference; COI-NJ has no amino acid changes but at least 13 nucleotide changes). Because of difficulty separating the species in this group morphologically, references to the GenBank sequences from Baker et al. (2020) are provided at the end of the material examined; O. taii (UCRCENT00243359; D4717) sequences are: 28S D2 (MH247391), 28S D3–5 (MH247544), COI-NJ (MH247756).
Key to species of the Orasema bakeri species group
1) Female petiole usually wider than long (PTL:PTW = 0.6–1.3), male PTL:PTW = 1.5–3.0; head wide (HH:IOD = 1.0–1.2); notauli relatively deep such that in dorsal view mesoscutal lateral lobes appear discontinuous with curvature of midlobe (Figs 12F, 16F)............................................................................................ 2
- Female petiole usually longer than wide (PTL:PTW = 0.8–1.5), male PTL:PTW = 0.8–4.9; head more triangular (HH:IOD = 1.2–1.5); notauli relatively shallow such that in dorsal view mesoscutal lateral lobes appear continuous with curvature of midlobe (Figs 13F, 14F, 15F)............................................................................... 3
2) Midlobe of mesoscutum with medial impression, lateral lobes reticulate to finely imbricate on dorsal surface (Fig. 16F); upper mesepisternum reticulate (Fig. 16C); female scape yellow (Fig. 16D); male antenna with setae semi-erect, curved (Fig. 16E); propodeum with medial carina (Fig. 16G) (southern Nearctic)................................ Orasema texana Gahan
- Midlobe of mesoscutum without medial impression, lateral lobes reticulate with smooth patch on dorsal surface (Fig. 12F); upper mesepisternum smooth to imbricate (Fig. 12C); female scape dark brown with iridescence (Fig. 12D); male antenna with setae closely appressed, straight (Fig. 12E); propodeum without medial carina (Fig. 12G) (United States: TX, NC, SC)........................................................................................ Orasema bablyi n. sp.
3) Clava with distinct ventral notch separating two proximal clavomeres ventrally (dorsally fused) (cf. Chien & Heraty 2018, fig. 8) (United States: TX).......................................................... Orasema taii Chien & Heraty
- Clava without ventral notch, clavomeres completely fused..................................................... 4
4) Fore wing with marginal fringe present; female often with medial, differentially-colored depression on mesoscutellum (Fig. 15F); male petiole often short (PTL:PTW = 0.8–2.7) (central to southern Mexico)............ Orasema polymyrmex n. sp.
- Fore wing with marginal fringe sometimes absent; female without medial, differentially-colored depression on mesoscutellum; male petiole long (PTL:PTW = 2.8–5.0)................................................................... 5
5) Body size usually slightly larger (female 3.0– 3.5 mm, male 2.4–3.0 mm); body usually with more green coloration (Fig. 13A) (widespread Nearctic)................................................................ Orasema bakeri Gahan
- Body size usually smaller (female 2.2–3.2 mm, male 1.7–2.8 mm); body usually with more violaceous or blue coloration (Fig. 14A) (widespread Nearctic)........................................................... Orasema dubitata n. sp.
description: Published as part of Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), pp. 1-84 in Zootaxa 4888 (1) on pages 23-25, DOI: 10.11646/zootaxa.4888.1.1, http://zenodo.org/record/4297699