Conostigmus muesebecki Dessart & Masner 1965

Trietsch, Carolyn, Mikó, István, Ezray, Briana & Deans, Andrew R., 2020, A Taxonomic Revision of Nearctic Conostigmus (Hymenoptera: Ceraphronoidea: Megaspilidae), Zootaxa 4792 (1), pp. 1-155 : 54-58

Conostigmus muesebecki Dessart & Masner 1965

Fig. 31

Species Comments and History. Dessart and Masner (1965) described this species from a holotype female, allotype male, and multiple paratypes (6 males and 22 females from different collecting events), all present at the USNM. This species was originally described as the type species of a new genus, Ecnomothorax ( Dessart and Masner, 1965) , which was later synonymized with Conostigmus by Dessart and Cancemi (1987).

Dessart dissected the allotype male and made a slide preparation of the male genitalia, deposited in the USNM. However, this male genitalia preparation is in such poor condition that it is not possible to verify any characters from it. We were not able to dissect any of the other paratype males present at the USNM or locate any other males to dissect for this revision. From illustrations of the male genitalia provided in Dessart and Masner (1965), this species appears to have the following characters: medioventral conjunctiva of the gonostyle–volsella complex absent (parossiculi independent, not fused); 1 apical parossicular seta; proximal end of the dorsomedian conjunctiva of the gonostyle–volsella complex shape blunt, without a dorsomedian projection; harpe shorter than the gonostipes in lateral view; 2 gonossicular spines, potentially with an additional dorsal apodeme below the second spine; and one gonossicular spine more than 2× as long as the other(s).

Variability. Other than slight intraspecific variations in color and size between specimens, we did not note any substantial variations.

Differences Between Males and Females. Other than genitalia differences and sexual dimorphism in the antennae, there are no obvious differences between males and females.

Diagnosis. This species is easily distinguished by the reduced wings (brachypterous), the absence of the median mesoscutal sulcus, and the presence of an enlarged pronotum (pronotum longer than the mesoscutum along the midline).

Similar Nearctic species include C. dimidiatus , which can have the median mesoscutal sulcus absent or present, but does not have an enlarged pronotum. There are no other species in the Nearctic with an enlarged pronotum beside C. muesebecki —the only other known Conostigmus species in the world with this character is C. grangeri , known only from Morocco. Conostigmus grangeri differs from C. muesebecki in size ( C. grangeri is larger), coloration ( C. grangeri has a two-toned body, whereas C. muesebecki has uniform body coloration), presence and length of the preoccipital furrow (preoccipital furrow ends at the site of the postocellar carina in C. muesebecki ; preoccipital furrow absent or ending posterior to the ocellar triangle in C. grangeri ) and male genitalia characters (compare Fig. 18 and 19 with Fig. 22 and 23 in Dessart and Masner, 1965).

Description. Note: Because we were unable to dissect any male specimens for observation, we have omitted scorings for male genitalia characters in the redescription below. The measurements given below were taken from two female specimens, PSUC_FEM 66226 (TAMU) and CMNHENT0022724 (CLEV) respectively.

Body length: 1.2 mm, 1.2 mm. Color hue pattern in male: cranium, metasoma, flagellomeres brown to black; anterior half of mesosoma yellow to light brown; posterior half of mesosoma light brown to brown; legs, scape, pedicel ochre to light brown. Color intensity pattern in male: anterior half of mesosoma lighter than posterior half of mesosoma; flagellomeres darker than scape and pedicel. Color hue pattern female: cranium, mesosoma, metasoma, scape yellow to light brown; coxae and legs white to ochre; pedicel white to ochre; flagellomeres white to brown. Color intensity pattern female: pedicel, F1, F2 lighter than F6–F9; flagellomeres gradually darkening towards the apex; anterior half of metasoma lighter than posterior half of metasoma; anterior half of mesosoma lighter than posterior half of mesosoma. Color intensity dorsal and ventral to the site of the sternaulus: concolorous. Color intensity pattern of syntergite: petiole neck and anterior region of syntergite lighter in coloration than the posterior region of the syntergite. Foveolate sculpture on body count: absent. Rugose sculpturing count: absent. Rugose region on upper face count: absent.

Antennae: Longest male flagellomere: F9. Female scape length vs. pedicel length: 3.13, 3.25. Female scape length vs. F1 length: 3.57, 4.33. Female F1 length vs. F2 length: 1.75, 1.50. Female F1 length vs. pedicel length: 0.88, 0.75. Longest female flagellomere: F9. Length of setae on male flagellomere vs. male flagellomere width: setae shorter than width of flagellomeres.

Head: Head width, dorsal view: at least 1.5× wider than mesosoma. Head height (HH, lateral view) vs. eye height (EHf, anterior view): HH:EHf=1.71, 1.81. Head height (HH) vs. head length (HL): HH:HL=1.26, 1.32. Head width (HW) vs. interorbital space (IOS): HW:IOS=1.75, 1.68. Head width (HW) vs. head height (HH): HW: HH=1.17, 1.10. Cephalic size (csb): Mean: 260 μm, 305 μm. Maximum eye diameter vs. minimum eye diameter: 1.56, 1.55. POL:OOL: POL equal to or shorter than OOL and ocellar triangle with short base. Female ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL:LOL=3.0, 1.5. Head shape (anterior view): circular or triangular. Preoccipital lunula count: absent. Preoccipital carina count: absent. Occipital carina structure: occipital carina not complete. Occipital carina sculpture: crenulate. Preoccipital furrow count: present. Preoccipital furrow anterior end: preoccipital furrow ends at site of postocellar carina. Postocellar carina count: present. Dorsal margin of occipital carina vs. dorsal margin of lateral ocellus in lateral view: occipital carina ventral to lateral ocellus in lateral view. Transverse scutes on upper face count: absent. Transverse frontal carina count: absent. Randomly sized areolae around setal pits on upper face count: absent. Setal pit on vertex size: smaller than diameter of scutes. Ventromedian setiferous patch and ventrolateral setiferous patch count: absent. White, thick setae on upper face count: absent. Antennal scrobe count: absent. Facial structure count: facial pit present. Facial pit count: present. Facial sulcus count: absent. Median facial keel count: absent. Supraclypeal depression count: present. Supraclypeal depression structure: present medially, inverted U-shaped. Intertorular area count: present. Intertorular carina count: present. Median process on intertorular carina count: present. Median process on intertorular carina shape: acute. Median process of intertorular carina structure: process extends across intertorular area towards dorsal margin of clypeus. Median region of intertorular area shape: convex. Ventral margin of antennal rim vs. dorsal margin of clypeus: not adjacent. Torulo–clypeal carina count: present. Subtorular carina count: absent. Mandibular tooth count: 2. Mandibular lancea count: absent.

Mesosoma: Anterior mesoscutal width (AscW) vs. posterior mesoscutal width (PscW): AscW/PscW=0.38, 0.40. Mesoscutal length (MscL) vs. anterior mesoscutal width (AscW): MscL/AscW=2.0, 1.75. Mesoscutal length (MscL) vs. mesoscutellar length (MscIL): MscL:MscIL= 0.67, 0.58. Wing count: absent. Fore wing size: wings reduced or brachypterous with apex never extending past scutellum. Pronotum median length: greater than longest median anatomical line of the mesoscutum. Notaulus count: present. Crenulae of notaulus width: width of the crenulae does not increase more than 2× anteriorly. Median mesoscutal sulcus count: absent. Axillular carinae count: absent. Speculum ventral limit: not extending ventrally of pleural pit line. Metapleural sulcus shape: straight. Mesometapleural sulcus count: present. Ventrolateral invagination of the pronotum count: present. Sternaulus count: absent. Epicnemial carina count: complete. Epicnemium posterior margin shape: anterior discrimenal pit present; epicnemial carina curved. Transverse striations on the ventral metapleural area count: absent. Scutes on posterior region of mesoscutum and dorsal region of mesoscutellum convexity: flat. Ventral projection of the metapleural carina count: absent. Lateral propodeal carina count: present. Lateral propodeal carina shape: inverted “U” (left and right lateral propodeal carina are adjacent to the antecostal sulcus of the first abdominal tergum submedially). Mesopostscutellum count: absent (scutellum flat). Anteromedian projection of the metanoto–propodeo–metapecto–meso-pectal complex count: absent. Paired blue iridescent ovoid patches on the syntergite count: absent.

Distribution. Nearctic.

Material Examined. Holotype female: USA: Arkansas: USNMENT01339792 ( USNM) . Paratypes (22 females, 8 males): USA: Arkansas: 11 females, 2 males. USNMENT 01212943, 01212976, 01212978 - 01212980, 01212982, 01212983, 01212986 – 01212990, 01212992 ( USNM) . USA: Missouri: 11 females, 6 males. USNMENT 01212941, 01212945 – 01212947, 01212949, 01212951, 01212955, 01212957, 01212959, 01212975, 01212977, 01212981, 01212984, 01212985, 01212991, 01212993, 01212994 ( USNM) .

Non-type material (2 females): USA: South Carolina: 1 female. CMNHENT0022724 ( CLEV). USA: Texas: 1 female. PSUC _FEM 66226 ( TAMU) .

Figures

FIGURE 18. Conostigmus canadensis (Ashmead, 1888) female lectotype (USNMENT01339753). A. Lateral habitus. B. Anterior view of the frons.

FIGURE 19. Conostigmus canadensis (Ashmead, 1888) female lectotype (USNMENT01339753). A. Lateral view. B. Dorsal view. Abbreivations: pronotum (prn).

FIGURE 22. Conostigmus dimidiatus (Thomson, 1858) female lectotype (MZLU Type No. 5329) anterior view of the frons. Imaged by Christoffer Fägerström at the MZLU.

FIGURE 23. Conostigmus dimidiatus (Thomson, 1858) male genitalia. A. Ventral view (PSUC_FEM 34290). B. Lateral view (UCRC_ENT 00103613). C. Dorsal view (UCRC_ENT 00103613).

FIGURE 31. Conostigmus muesebecki Dessart & Masner, 1965 type specimens at the USNM. A. Male paratype (USN- MENT01212979) in dorsal view. B. Female holotype in lateral view (USNMENT01339792). Abbreviation: pronotum (prn).