Conostigmus nigrorufus Dessart 1997

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 : 58-63

Conostigmus nigrorufus Dessart 1997

Figs. 32 , 33

Species Comments and History. Dessart (1997a) described this species from male and female specimens collected in Ontario, Canada, as well as New York and Maryland, USA. The holotype male, allotype and one female paratype are deposited in the CNC, with additional paratypes deposited in the USNM and the Royal Belgian Institute of Natural Sciences in Belgium (RBINS), Brussels. We found the specimens at the CNC in good condition, but we did not find any paratype specimens at the USNM. As Dessart’s 1997a study was published near the end of his lifetime, it is unclear if the specimens were ever deposited in the USNM. The presence or status of specimens at the RBINS remains unconfirmed.

Variability. This species has a large size variation, with some larger specimens having more rugose sculpturing on the frons and head. The gonocondyle is also blunt in some male specimens (PSUC_FEM 45241, PSUC_FEM 88173) and acute in others (PSUC_FEM 64076, PSUC_FEM 15380). This character being blunted or pointed could be a function of this extreme size difference.

There is also variation in coloration. This species is easily recognizable by the yellow-to-orange coloration on the anterior half of the mesosoma, lighter than the posterior half of the mesosoma, which is brown to dark brown. However, some specimens have the entire pronotum and mesoscutum the same lighter color, whereas others have darker brown patches across the mesoscutum. Sometimes the pronotum will be yellow to orange in color, but the mesoscutum will be brown. On one female (CMNHENT0022708), not only is the lighter coloration present on the pronotum and mesoscutum, but also on the axilla. This color variation could be attributed to geographical range, nutrition, temperature, or other factors.

Differences Between Males and Females. The median process on the intertorular carina is absent in females but present and blunt in males. Other than this, as well as genitalia differences and sexual dimorphism in the antennae, there are no obvious differences between males and females.

Diagnosis. This species is distinguished from other Nearctic Conostigmus by the following combination of characters: facial pit present; median process on intertorular carina and blunt; occipital carina not complete; preoccipital lunula present; preoccipital furrow present and crenulate; wings present and macropterous; sternaulus absent; and the harpe shorter than the gonostipes in lateral view. This species also has unique coloration, with the anterior half of the mesosoma yellow to orange in color and lighter than the posterior half of the mesosoma, which is brown to dark brown. This unique coloration and the somatic characters listed above are found in both males and females and can be used to match them.

The most similar Nearctic species is C. erythrothorax , which also lacks a sternaulus and can have similar coloration in both males and females. However, a major difference between these two species is that C. erythrothorax is always brachypterous, whereas C. nigrorufus is always macropterous. Other differences include the preoccipital furrow, which is present and crenulate in C. nigrorufus and is either absent or appears as a smooth impression in C. erythrothorax .

Description. Body length: 1.65–2.50 mm. Color hue pattern in male: cranium, axillula, posterior half of mesosoma light brown to dark brown; anterior half of mesosoma yellow to orange; supraclypeal depression yellow to dark brown; F1–F9 light brown to dark brown; hind coxa and petiole neck light yellow to white. Color intensity pattern in male: flagellomeres and their branches darker than scape and pedicel. Scape and pedicel same as legs; anterior half of mesosoma lighter than posterior half of mesosoma. Color hue pattern female: cranium, axillula, posterior half of mesosoma light brown to dark brown; anterior half of mesosoma yellow to orange; supraclypeal depression yellow to dark brown; F1–F9 light brown to dark brown; hind coxa and petiole neck light yellow to white. Color intensity pattern female: flagellomeres and their branches darker than scape and pedicel. Scape and pedicel same as legs; 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; present.

Antennae: Male scape length vs. pedicel length: 3.6–4.5. Male scape length vs. F1 length: 1.3–1.5. Male F1 length vs. pedicel length: 2.6–3.4. Male F1 length vs. male F2 length: 1.1–1.4. Longest male flagellomere: F1. Female scape length vs. pedicel length: 4.0–4.3. Female scape length vs. F1 length: 2.7–3.4. Female F1 length vs. F2 length: 1.4–1.8. Female F1 length vs. pedicel length: 1.2–1.6. Longest female 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): male HH:EHf=1.2–1.7; female HH:EHf=1.5–2.0. Head height (HH) vs. head length (HL): HH:HL=1.1–1.4. Head width (HW) vs. interorbital space (IOS): male HW:IOS=1.7–2.0; female HW:IOS=1.9–2.2. Head width (HW) vs. head height (HH): male HW: HH=1.2–1.4; female HW:IOS=0.9–1.3. Cephalic size (csb): Mean: 375–555 μm. Maximum eye diameter vs. mini- mum eye diameter: 1.1–1.5. 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=1.2–2.0. Male ocular ocellar line (OOL) vs. posterior ocellar line (POL): OOL:POL=0.8–1.3. Male ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.2–2.0:1.3–1.5:1.0. Female ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL 1.2–1.8× as long as LOL. Female ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.2–1.8:1.3–1.8:1.0. Head shape (anterior view): circular or triangular. Preoccipital lunula count: present. 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 posterior to ocellar triangle. Preoccipital furrow sculpture: crenulate. 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: present. Region on upper face width transverse scutes lateral limit: restricted to lateral branches of supraclypeal depression. 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: no external corresponding structure present. Facial pit count: absent. Facial sulcus count: absent. Median facial keel count: absent. Supraclypeal depression count: present. Supraclypeal depression structure: absent medially, represented by two grooves laterally of facial pit. Intertorular area count: present. Intertorular carina count: present. Median process on intertorular carina count: present in males but not in females. Median process on intertorular carina shape: blunt on males, median process absent in females. 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=550–780 μm. Anterior mesoscutal width (AscW) vs. posterior mesoscutal width (PscW): AscW/PscW=0.6–0.8. Mesoscutal length (MscL) vs. anterior mesoscutal width (AscW): MscL/ AscW=1.2–1.8. Mesoscutal length (MscL) vs. mesoscutellar length (MscIL): MscL:MscIL= 0.9–1.1. 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. 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: present. Ventral projection of the metapleural carina length: less than 2× as long as wide. Lateral propodeal carina count: present. Lateral propodeal carina shape: straight (left and right lateral propodeal carinae compose a carina that is not broken medially). 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: concave. Paired blue iridescent ovoid patches on the syntergite count: absent. Shortest width of petiole neck vs. syntergal translucent patch maximum width: 2.0–2.3. Shortest width of petiole neck vs. synsternal translucent patch maximum width: 1.9–2.4. Syntergal translucent patch maximum width vs. minimum width: 1.4–2.0. Synsternal translucent patch maximum width vs. minimum width: 1.4– 1.9. Syntergal translucent patch maximum width orientation: anterolaterally. Synsternal translucent patch maximum width orientation: anterolaterally. Synsternal setiferous patch shape: linear, with a patch of setae lateral or posterior to the synsternal translucent patch. Synsternal setiferous patch structure: comprised of a single or double row of setae anterior to the synsternal translucent patch, with a patch of setae lateral or posterior to the synsternal translucent patch. Synsternal setiferous patch anterior end: synsternal setiferous patch begins anterior to the synsternal translucent patch anterior margin. Synsternal setiferous patch posterior end: synsternal setiferous patch ends posterior to the synsternal translucent patch posterior margin. Synsternal setiferous patch length vs. synsternal translucent patch maximum width: synsternal setiferous patch at least as long as the maximum width of the synsternal translucent patch but not 2× as long. S1 length vs. shortest width: S1 wider than long.

Male Genitalia: Distal margin of male S9 shape: convex. Proximolateral corner of male S9 shape: blunt. 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 transverse row of distal setae occurring medially with less than 4 setae below it. 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 Ushape). Proximodorsal notch of cupula width vs length: wider than long. Proximolateral projection of the cupula shape: blunt. Gonocondyle count: present. Gonocondyle shape: blunt; acute. Distodorsal margin of cupula shape: concave. Distoventral submedian corner of the cupula count: absent. Dorsomedian projection of the gonostyle–vol-sella complex count: absent. Dorsomedian conjunctiva of the gonostyle–volsella complex count: present. Dorso median conjunctiva of the gonostyle–volsella complex length relative to length of gonostyle–volsella complex: dorsomedian conjunctiva extending between 1/3 to 1/2 the 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: present. Distal projection of the penisvalva count: absent. Gonossiculus spine count: 3. 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: blunt or straight. Lateral setae of harpe count: present. Lateral setae of harpe orientation: oriented distolaterally. 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: convex.

Distribution. Nearctic.

Material Examined. Holotype male: CANADA: PSUC _FEM 31468 ( CNC) . Paratypes (1 female): USA: New York : 1 female. PSUC _FEM 31472 ( CNC) .

Non-type material (14 females, 12 males): CANADA: Ontario: 1 female. PSUC _FEM 56130 ( CNC). USA: Illinois: 1 female, 1 male. INHS Insect Collection 14055, 287550 ( INHS). USA: Michigan: 1 female. PSUC _ FEM 86365 ( PSUC). USA: Minnesota: 1 female. PSUC _FEM 66203 ( UMSP). USA: Ohio: 2 females, 8 males. PSUC _FEM 64076, 86140 , 86149 , 86265 , 86324 , 86397 , 86407 ( OSUC); PSUC _FEM 50276 ( WIRC); CMN- HENT0022708, 0022712 ( CLEV). USA: Pennsylvania: 7 females, 1 male. PSUC _FEM 15380, 50113 , 50114 , 83801 , 84010 , 91435 , 98074 , 148618 ( PSUC). USA: Wisconsin: 1 female, 2 males. PSUC _FEM 45241, 88173 , 92614 ( WIRC) .

Figures

FIGURE 32. Conostigmus nigrorufus Dessart, 1997 holotype male (PSUC_FEM 31468). A. Lateral view. B. Dorsal view.

FIGURE 33. Conostigmus nigrorufus Dessart, 1997 A. Ventral view, with blunt gonocondyle (PSUC_FEM 45241). B. Ventral view, with acute gonocondyle (PSUC_FEM 15380). C. Dorsal view (INHS Insect Collection 287550). D. Lateral view (PSUC_FEM 45241).