Conostigmus michaeli Trietsch, 2020

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 : 122-126

Conostigmus michaeli Trietsch sp. nov.

Figs. 68 , 69

Diagnosis. This species can be differentiated from all other Nearctic Conostigmus by the following combination of characters: median process on the intertorular carina present and blunt; facial pit absent; occipital carina not complete; postocellar carina absent; preoccipital furrow present or absent, but if present, then appearing as a faint impression, never crenulate; sternaulus absent; wings present and macropterous; medioventral conjunctiva of the gonostyle–volsella complex present (parossiculi independent); and proximal end of the dorsomedian conjunctiva of the gonostyle–volsella complex shape acute. This species also has unique coloration, with the head and mesosoma lighter than the metasoma, the posterior half of the metasoma darker than the anterior half, and the flagellomeres darker than the head, mesosoma, scape, and pedicel. The anterior half of the metasoma is yellow to brown, whereas the posterior half of the metasoma is dark brown to black.

The female is unknown for this species.

Similar species include C. erythrothorax , which also has an incomplete occipital carina and lacks a facial pit, postocellar carina, and sternaulus. The two species also have similar male genitalia, with the medioventral conjunctiva of the gonostyle–volsella complex present (parossiculi independent), proximal end of the dorsomedian conjunctiva of the gonostyle–volsella complex shape acute, one apical parossicular seta, gonocondyle acute, and the proximodorsal notch of cupula present, U-shaped and wider than long. However, these two species differ in that all known specimens of C. erythrothorax are brachypterous, whereas all known specimens of C. michaeli are macropterous. There are also differences in the ocellar triangle ratios, with OOL:POL equal to 1.0 in C. erythrothorax males but less than 0.8 in C. michaeli males, and OOL:LOL over 1.6 in C. erythrothorax males but equal to or less than 1.3 in C. michaeli males.

It is possible that these differences could be intraspecific based on nutrition, locality, and the presence or absence of the wings; however, the smallest specimens of C. michaeli are the same size as the largest specimens of C. erythrothorax . There are no macropterous C. erythrothorax and no brachypterous C. michaeli known, but even such a variable species as C. bipunctatus that has macropterous and brachypterous forms still does not have differences in ocellar ratios as great as those observed between C. erythrothorax and C. michaeli . Future work could show these two species to represent different populations of macropterous and brachypterous forms of the same species, but until such work proves otherwise, it is our hypothesis that these are two different species.

Variability. As in C. erythrothorax , the preoccipital furrow can be present in some specimens (PSUC_FEM 34214, PSUC_FEM 34055, PSUC_FEM 33153) and absent in others (PSUC_FEM 5345, PSUC_FEM 34151, PSUC_FEM 34078). When present, it appears as a faint impression, never as a crenulate carina, and it can appear to reach the ocellar triangle (PSUC_FEM 34214, PSUC_FEM 34055) or end posterior to it (PSUC_FEM 33153).

There is also variation in color within this species. Some specimens have lighter coloration (PSUC_FEM 34055, PSUC_FEM 34078) than others (PSUC_FEM 34214, PSUC_FEM 34232), though all have darker coloration on the posterior half of the metasoma and the dorsal half of the cranium. Some specimens even have coloration reminiscent of C. nigrorufus , with the anterior half of the mesosoma yellow (PSUC_FEM 34078, PSUC_FEM 34156).

Concerning the color intensity dorsal and ventral to the site of the sternaulus: on some specimens the area ventral to the site of the sternaulus is lighter than the area dorsal to the site of the sternaulus (PSUC_FEM 34055/UCFC 381232, PSUC_FEM 5345), whereas on other specimens these two regions are concolorous (PSUC_FEM 34078, PSUC_FEM 34214).

Description. Body length: 1.275 –1.425 mm. Color hue pattern in male: cranium, mesosoma yellow to brown; legs except coxae, scape, pedicel ochre to brown; anterior half of metasoma yellow to brown; posterior half of metasoma dark brown to black; coxae white to ochre; flagellomeres brown to dark brown. Color intensity pattern in male: flagellomeres darker than scape and pedicel; anterior half of metasoma lighter than posterior half of metasoma; propleuron lighter than the rest of the mesosoma; petiole neck lighter than rest of metasoma; ventral region of cranium is lighter than dorsal region of cranium; anterior half of mesosoma lighter than posterior half of mesosoma. Color intensity dorsal and ventral to the site of the sternaulus: concolorous; area ventral to the site of the sternaulus lighter than the area dorsal to the site of the sternaulus. 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: Male scape length vs. pedicel length: 3.2–3.7. Male scape length vs. F1 length: 1.2–1.4. Male F1 length vs. pedicel length: 2.4–2.9. Male F1 length vs. male F2 length: 1.0–1.2. Longest male flagellomere: F1. Length of setae on male flagellomere vs. male flagellomere width: setae shorter than width of flagellomeres. Sensillar patch of the male flagellomere pattern: F6–F9.

Head: Head width, dorsal view: equal to or only slightly wider than mesosoma (less than 1.3× wider than mesosoma). Head height (HH, lateral view) vs. eye height (EHf, anterior view): HH:EHf=1.2–1.8. Head height (HH) vs. head length (HL): HH:HL=1.1–1.3. Head width (HW) vs. interorbital space (IOS): HW:IOS=1.9–2.2. Head width (HW) vs. head height (HH): HW:HH=1.2–1.5. Cephalic size (csb): Mean: 300–450 μm. Maximum eye diameter vs. minimum eye diameter: 1.3–1.5. POL:OOL: POL equal to or shorter than OOL and ocellar triangle with short base OR POL longer than OOL and ocellar triangle with wide base. Male ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL:LOL=1.1–1.3. Male ocular ocellar line (OOL) vs. posterior ocellar line (POL): OOL:POL=0.6–0.8. Male ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.1–1.3:1.2–2.0:1.0. Head shape (anterior view): circular or triangular. Preoccipital lunula count: absent. Preoccipital carina count: present. Occipital carina structure: occipital carina not complete. Occipital carina sculpture: crenulate. Preoccipital furrow count: absent; present. Preoccipital furrow anterior end: preoccipital furrow ends posterior to ocellar triangle; preoccipital furrow ends at site of postocellar carina. Preoccipital furrow sculpture: appearing as a faint impression, smooth. Postocellar carina count: absent. Dorsal margin of occipital carina vs. dorsal margin of lateral ocellus in lateral view: occipital carina dorsal 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: blunt. Median process of intertorular carina structure: process does not extend across intertorular area to 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: Weber length: WL=440–600 μm. Anterior mesoscutal width (AscW) vs. posterior mesoscutal width (PscW): AscW/PscW=0.7–0.9. Mesoscutal length (MscL) vs. anterior mesoscutal width (AscW): MscL/ AscW=1.4–1.7. Mesoscutal length (MscL) vs. mesoscutellar length (MscIL): MscL:MscIL= 0.8–1.2. Wing count: present. Fore wing size: wings present and macropterous with apex extending past petiole. Pronotum median length: less 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. Notaulus posterior end location: adjacent to transscutal articulation. Posterior region of notaulus orientation: posterior end of notaulus curves and is adjacent to median mesoscutal sulcus. Median mesoscutal sulcus count: present. Median mesoscutal sulcus posterior end: adjacent to transscutal articulation. Scutoscutellar sulcus vs. transscutal articulation location: adjacent. 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. Sternaulus length: sternaulus 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–mesopectal complex count: absent. Posterior margin of nucha in dorsal view shape: concave.

Metasoma: Transverse carina on petiole shape: straight. Paired blue iridescent ovoid patches on the syntergite count: absent. Shortest width of petiole neck vs. syntergal translucent patch maximum width: 2.2–2.7. Shortest width of petiole neck vs. synsternal translucent patch maximum width: 1.8–2.3. Syntergal translucent patch maximum width vs. minimum width: 1.0–1.8. Synsternal translucent patch maximum width vs. minimum width: 1.4–2.0. Syntergal translucent patch maximum width orientation: anterolaterally. Synsternal translucent patch maximum width orientation: anterolaterally. Synsternal setiferous patch shape: linear. Synsternal setiferous patch structure: comprised of a single row of setae. Synsternal setiferous patch anterior end: synsternal setiferous patch begins lateral to the synsternal translucent patch anterior margin. Synsternal setiferous patch posterior end: synsternal setiferous patch ends lateral to the synsternal translucent patch posterior margin. Synsternal setiferous patch length vs. synsternal translucent patch maximum width: synsternal setiferous patch as long as the maximum width of the synsternal translucent patch. S1 length vs. shortest width: S1 wider than long.

Male Genitalia: Distal margin of male S9 shape: convex. Proximolateral corner of male S9 shape: acute. Male S9 distal setal line/setal patch count: distal setae composing transverse setiferous line or lines. Male S9 distal setal line / setal patch structure: single or double transverse row of distal setae. Distomedian hairless area interrupting transverse row of setae or patch on male S9 count: absent with distal setiferous patch/line continuous medially. Submedial projections on proximal margin of S9 count: absent. Cupula length vs. gonostyle–volsella complex length: cupula less than 1/2 the length of gonostyle–volsella complex in lateral view. Proximodorsal notch of cupula count: present. Proximodorsal notch of cupula shape: arched (inverted U-shape). Proximodorsal notch of cupula width vs length: wider than long. Proximolateral projection of the cupula shape: blunt. Gonocondyle count: present. Gonocondyle shape: acute. Distodorsal margin of cupula shape: concave. Distoventral submedian corner of the cupula count: absent. Dorsomedian projection of the gonostyle–volsella complex count: absent. Dorsomedian conjunctiva of the gonostyle–volsella complex count: present. Dorsomedian conjunctiva of the gonostyle–volsella complex length relative to length of gonostyle–volsella complex: dorsomedian conjunctiva extending more than or equal to 2/3 of length of gonostyle–volsella complex in dorsal view. Dorsomedial margin of gonostyle–volsella complex shape: V-shaped. Proximal end of dorsomedian conjunctiva of the gonostyle–volsella complex shape: acute or V-shaped. Parossiculus count or parossiculus and gonostipes fusion: present and parossiculi not fused with the gonostipes. Medioventral conjunctiva of the gonostyle–volsella complex count or fusion of parossiculi: medioventral conjunctiva present and parossiculi independent or fused proximally.Apical parossicular setae count: one. Distal projection of the parossiculus count: absent. Distal projection of the penisvalva count: absent. Gonossiculus spine count: 3. Gonossiculus spine length: one spine not more than 2× as long as the other(s) (spines of similar lengths). Harpe length: harpe shorter than gonostipes in lateral view. Harpe shape: simple and not bilobed. Harpe orientation: medial. Lateral margin of harpe shape: widest point of harpe is at its articulation site with gonostyle–volsella complex. Distal margin of harpe in lateral view: acute or pointed. Lateral setae of harpe count: present. Lateral setae of harpe orientation: oriented distally. Lateral setae on harpe density: setae sparse. Dense patch of setae on the distoventral edge of the harpe count: absent. Distal setae on harpe length: setae of equal length across distal end of harpe. Distodorsal setae of sensillar ring of harpe length vs. harpe width in lateral view: setae as long as or shorter than harpe width. Distodorsal setae of sensillar ring of harpe orientation: distomedially. Sensillar ring area of harpe orientation: distomedially. Sensillar ring shape: circular. Distoventral margin of harpe in lateral view: straight.

Distribution. Nearctic.

Etymology. This species is named michaeli in honor of the first author’s father, Michael Thomas Trietsch, for his love and support during the course of this research.

Material Examined. Holotype male: USA: Florida: PSUC _FEM 34232, UCFC 88670 ( UCFC) . Paratypes (7 males): USA: Florida: 6 males. PSUC _ FEM 5345 , 33153 , 34055 , 34141 , 34156 , 34214 ( UCFC) . USA: Texas: 1 male. PSUC _FEM 34078 ( TAMU) .

Figures

FIGURE 68. Conostigmus michaeli Trietsch sp. nov., male holotype (PSUC_FEM 34232). A. Lateral view. B. Dorsal view.

FIGURE 69. Conostigmus michaeli Trietsch sp. nov., paratype male genitalia (PSUC_FEM 34214). A. Ventral view. B. Dorsal view.