Conostigmus laeviceps ( Ashmead, 1893 )

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 : 49-54

Conostigmus laeviceps ( Ashmead, 1893)

Figs. 28 , 29

Species Comments and History. Ashmead (1893) described this species from an unknown number of male specimens. One specimen was collected by E. A. Schwarz in Bladensburg, Maryland; the others were collected by Ashmead along the bank of the Potomac River in Arlington, Virginia, and in the outskirts of Washington, D.C. ( Ashmead, 1893). There are four male specimens present at the USNM representing these localities, with one from Maryland, one from Virginia, and two from Washington, D.C. We also found an additional male specimen present at the MCZC bearing an identification label from Ashmead, but this specimen does not have a locality label, so it is not possible to verify whether it was also part of the original type series.

At the USNM, the male lectotype from Maryland (USNMENT01339759) is in relatively good condition, though the left antenna is missing flagellomeres 7, 8 and 9, and the right antenna is missing flagellomeres 8 and 9. This specimen damage was not mentioned in Masner and Muesebeck (1968) and must have occurred since then. The male paralectotype from Virginia (USNMENT 01212998) is in better condition than the type and is not missing any pieces. Both of the paralectotypes from Washington, D.C., are in poor condition, with one (USNMENT 01212996) missing the antennae and metasoma, and the other (USNMENT 01212997) missing the head and metasoma .

We were not able to dissect the male genitalia from the type specimens, but we obtained permission to dissect the MZCU specimen and recognized the genitalia immediately by its fused parossiculi and the unique harpe. This species is widespread and common across the United States, with one specimen known from Canada. Though we were not able to dissect the type specimens, the lectotype and the paratype from Virginia have enough of the harpe protruding from the metasoma to see the unique harpe shape and confirm the species. The two additional paratypes from Washington, D.C., were too damaged to confirm the species, though we still include them below with the material examined.

Variability. The median process of the intertorular carina extends down across the intertorular area towards the dorsal margin of the clypeus, but in some specimens it reaches the clypeus (PSUC_FEM 8993, PSUC_FEM 50076), whereas in others it does not (CMNHENT0022709, PSUC_FEM 16645). The distoventral margin of the harpe is usually straight, but can appear more convex in some specimens (PSUC_FEM 8795) and more concave in others (PSUC_FEM 50136).

Diagnosis. This species is distinguished by the following combination of characters: facial pit present; preoccipital furrow present; postocellar furrow present; median process on intertorular carina present and acute; sternaulus smooth (not crenulate), present and elongate, exceeding 3/4 of the mesopleuron length at the level of the sternaulus; ventral projection of the metapleural carina present; medioventral conjunctiva absent and parossiculi fused; medioventral ridge of the gonostyle–volsella complex present; gonossiculus with one spine more than 2× as long as the others; proximodorsal notch of cupula absent; gonocondyle present and acute; dorsomedian projection of the gonostyle–volsella complex present and simple (not bilobed); dorsomedian conjunctiva extending equal to or less than 1/3 of the length of the gonostyle–volsella complex in dorsal view; and proximal end of the dorsomedian conjunctiva of the gonostyle–volsella complex blunt or straight.

The female of this species is unknown.

The harpe of C. laeviceps and C. dessarti can appear very similar to each other in lateral view, in that they both have harpe with the distal margin pointed or acute, the distodorsal setae of sensillar ring longer than the harpe width (sometimes 2× as long or greater), and the distoventral margin of the harpe in lateral view straight, though it can appear more convex or concave in some specimens. These species can easily be distinguished by the proximal end of the dorsomedian conjunctiva of the gonostyle–volsella complex (acute in C. dessarti , blunt or straight in C. laeviceps ) and the dorsomedian projection of the gonostyle–volsella complex (absent in C. dessarti , present in C. laeviceps ). C. dessarti also differs from C. laeviceps in that the scape is more than 5.5× as long as the pedicel (less in C. laeviceps ).

C. laeviceps also shares many somatic characters and even some genitalia characters in common with C. bipunctatus , C. minimus , C. musettiae , and C. franzinii . Male genitalia characters are almost always necessary to separate these species. Conostigmus minimus and C. musettiae differ from C. laeviceps in that they have a dense patch of setae on the distoventral edge of the harpe (absent in C. laeviceps ) and lack the dorsomedian projection of the gonostyle–volsella complex (present in C. laeviceps ). Conostigmus franzinii also has a dense patch of setae on the distoventral edge of the harpe as well as the proximodorsal notch of the cupula (absent in C. laeviceps ). Conostigmus bipunctatus differs from C. laeviceps in that it has curved or sickle-shaped harpe in lateral view; it also has the dense patch of setae on the distoventral edge of the harpe.

Description. Body length: 1.625 –1.825 mm. Color hue pattern in male: cranium and mesosoma reddish–brown to black; flagellomeres light brown; legs, scape, pedicel, neck of petiole and anterior portion of metasoma yellow; posterior portion of metasoma reddish–brown. Color intensity pattern in male: cranium darker than mesosoma. Col- or 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: Male scape length vs. pedicel length: 3.7–5.4. Male scape length vs. F1 length: 1.0–1.3. Male F1 length vs. pedicel length: 3.2–4.8. Male F1 length vs. male F2 length: 1.3–1.5. 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: F5–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=1.5–2.0. Head height (HH) vs. head length (HL): HH:HL=1.1–1.3. Head width (HW) vs. interorbital space (IOS): HW:IOS=1.6–1.8. Head width (HW) vs. head height (HH): HW:HH=1.1–1.4. Cephalic size (csb): Mean: 335–480 μm. Maximum eye diameter vs. minimum eye diameter: 1.2–1.4. POL:OOL: POL equal to or shorter than OOL and ocellar triangle with short base. Male ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL:LOL=1.6–2.5. Male ocular ocellar line (OOL) vs. posterior ocellar line (POL): OOL:POL=1.4–2.0. Male ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.6–2.5:0.8–1.8:1.0. Head shape (anterior view): circular or triangular. Preoccipital lunula count: present. Preoccipital carina count: absent. Occipital carina structure: occipital carina complete. Occipital carina sculpture: crenulate. Preoccipital furrow count: present. Preoccipital furrow anterior end: preoccipital furrow ends inside ocellar triangle, but ends posterior to the anterior ocellus. 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: 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; 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=480–690 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=1.2–1.7. Mesoscutal length (MscL) vs. mesoscutellar length (MscIL): MscL:MscIL= 0.8–1.0. 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 does not curve and is not 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: present. Axillular carinae shape: the left and right carinae are separated posteromedially. 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: present. Sternaulus length: elongate and exceeding 3/4 of mesopleuron length at level of sternaulus. Sternaulus sculpture: smooth. 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: inverted “Y” (left and right lateral propodeal are adjacent medially posterior to antecostal sulcus of the first abdominal tergum, and connected to the antecostal sulcus by a median carina representing the median branch of the inverted “Y”). Mesopostscutellum count: absent (scutellum flat). Anteromedian projection of the metanoto–propodeo–metapecto–mesopectal complex count: absent. Posterior margin of nucha in dorsal view shape: straight.

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: 1.3–2.4. Shortest width of petiole neck vs. synsternal translucent patch maximum width: 2.1–3.2. Syntergal translucent patch maximum width vs. minimum width: 1.7–3.0. Synsternal translucent patch maximum width vs. minimum width: 1.2– 2.0. 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 row of setae anterior to the synsternal translucent patch, with a patch of setae 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 2× 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 transverse row of setae occurring medially with additional distal setae below it, sometimes organized in one or two additional transverse rows. 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: absent. Proximolateral projection of the cupula shape: blunt. Gonocondyle count: present. Gonocondyle shape: acute. Distodorsal margin of cupula shape: straight. Dorsomedian projection of the gonostyle–volsella complex count: present. Dorsomedian projection of the gonostyle–volsella complex shape: simple (not bilobed). 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 equal to or less than 1/3 of length of gonostyle–volsella complex in dorsal view. Dorsomedial margin of gonostyle–volsella complex shape: straight with a median projection. Proximal end of dorsomedian conjunctiva of the gonostyle–volsella complex shape: blunt or straight. 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 absent and parossiculi fused. Medioventral ridge of the gonostyle–volsella complex count (only applicable if medioventral conjunctiva of the gonostyle–volsella complex absent): present. Apical parossicular setae count: one. Distal projection of the parossiculus count: present. Distal projection of the penisvalva count: absent. Gonossiculus spine count: 2. Gonossiculus spine length: one spine more than 2× as long as the other(s). 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: absent. 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 not of equal length, longer setae present on distodorsal point 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: distoventrally. Sensillar ring area of harpe orientation: medioventrally. Sensillar ring shape: elongate. Distoventral margin of harpe in lateral view: straight but can be more convex or concave in some specimens.

Distribution. Nearctic.

Material Examined. Lectotype male: USA: USNMENT01339759 ( USNM) . Paralectotypes (3 males): USA: 2 males. USNMENT 01212996, 01212997 ( USNM) . USA: Virginia: 1 male. USNMENT 01212998 ( USNM) .

Non-type material (49 males): CANADA: Ontario: 1 male. PSUC _FEM 16445 ( ROME) . USA: Arizona: 6 males. PSUC _ FEM 8795 , 8799 , 8826 , 8905 , 9077 , 9549 ( OSUC) . USA: Connecticut: 1 male. PSUC _FEM 15253 ( PSUC) . USA: Kentucky: 3 males. PSUC _FEM 50136 ( HIC); PSUC _FEM 86114, 86309 ( PSUC) . USA: Ohio: 33 males. CMNHENT0022689, 0022709, 0022785, 0022790 ( CLEV); PSUC _ FEM 6652 , 8772 , 8889 , 8993 , 9044 , 9458 , 9465 , 9560 , 9666 , 26604 , 26672 , 26708 , 26747 , 26753 , 26788 , 26793 , 26867 , 26907 , 26917 , 26960 , 27136 , 27174 , 27203 , 27218 , 27290 , 28746 , 28910 , 50076 , 68554 ( OSUC) . USA: Pennsylvania: 2 males. CMNHENT0022722 ( CLEV); PSUC _ FEM 3016 ( PSUC) . USA: Tennessee: 1 male. CMNHENT0022745 ( CLEV) . USA: Wisconsin: 1 male. PSUC _FEM 50071 ( WIRC). Unknown country: 1 male. MCZ-ENT 711734 ( MCZC) .

Figures

FIGURE 28. Conostigmus laeviceps (Ashmead, 1893) male lectotype (USNMENT01339759). A. Lateral view. B. Dorsal view.

FIGURE 29. Conostigmus laeviceps (Ashmead, 1893) male genitalia. A. Ventral view (PSUC_FEM 8795). B. Lateral view (PSUC_FEM 50136). C. Dorsal view (PSUC_FEM 8795).Abbreviation: medioventral ridge of the gonostyle–volsella complex (mgv).