Conostigmus abdominalis ( Boheman, 1832 )

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 : 17-20

Conostigmus abdominalis ( Boheman, 1832)

Figs. 9 , 10

Species Comments and History. Boheman (1832) originally described Ceraphron abdominalis from a female specimen, noting that the species was abundant throughout “Smolandia et Vestrogothia” (pg. 330), now modern-day Sweden. Boheman (1832) also described the male of another species, Ceraphron tenuicornis , also found in “Smolandia”. Thomson (1858) synonymized the two species, noting the presence of the facial sulcus on both sexes, and transferred the species to Megaspilus . Both specimens are located at the NHRS.

Kieffer (1907) keyed, re-described and transferred the species to Conostigmus . He broadened the range of distribution and described a new variation, called testacea, from a female with lighter coloration collected in Scandinavia, now deposited in the MZLU. Kieffer (1907) described another new species, C. divisifrons , from a single female with a facial sulcus and lighter coloration, now deposited in the MNHN ( Fig. 16 in Trietsch et al., 2019). Kieffer (1907) also described a third species, C. foveatifrons , again from a single female specimen with different coloration, present at the MCSN.

Dessart (1972a) redescribed C. abdominalis , illustrated the male genitalia and male and female antennae for the first time, and treated C. abdominalis var. testacea , C. divisifrons , and C. foveatifrons as junior synonyms. Dessart (1983a) synonymized two more species with Conostigmus abdominalis : C. pilosiceps Szabo, 1979 , and C. curvilineaticeps Szabo, 1979 , both described from single female specimens present at the HNHM.

After encountering so many synonyms of C. abdominalis, Dessart turned to the Nearctic species C. pulchellus , expecting another synonym (1997a). He was surprised to find that although they shared many somatic characters, such as the presence of a facial sulcus and elongate sternaulus, C. pulchellus and C. abdominalis differed in male genitalia characters and Dessart concluded that they were separate species.

At the time of Dessart’s 1997a publication, Conostigmus abdominalis was only reported from the Palearctic. Here, we report male specimens from the Nearctic, overlapping in range with Conostigmus pulchellus .

One paratype of C. pulchellus present at the NHMUK (NHMUKENT010812165) bears a label from Dessart identifying it as a “ C. abdominalis , (BOH 1832), syn. nov.”. However, Dessart did not mention this specimen in his 1997a publication. Presumably, Dessart thought the two species were synonymous when he left his label in 1975, as his 1997a paper expresses his surprise to find they are not synonymous. Dissection of the genitalia would be needed to confirm whether this specimen is indeed C. abdominalis , but if it were true, this would indicate that C. abdominalis has been present in the Nearctic since at least 1930.

Variability. The facial sulcus is always present and is usually well-defined with a crenulate carina ( PSUC _FEM 50242, PSUC _FEM 34020, PSUC _FEM 86279), but there are two specimens from Ohio where the facial sulcus is smooth instead of crenulate (CMNHENT0022737, CMNHENT0022804) .

In the male genitalia, the number of apical setae on the parossiculi vary between 1 (PSUC_FEM 148696, PSUC_FEM 83702) and 3 (PSUC_FEM 88175, NCSU 0055614), but there are never 4 or more (which only occurs in C. pulchellus ). The male harpe are distinctly spatulate or spoon-shaped, with the widest part of the harpe occuring between the proximal 1/3 rd (PSUC_FEM 148540, PSUC_FEM 148563) and proximal 2/3 rds (PSUC_FEM 50143, PSUC_FEM 86312). Three specimens (PSUC_FEM 26786, PSUC_FEM 50171 and UCRC_ENT 00457086) have harpe that are barely spatulate, and the widest point of the harpe is at the articulation site with the gonostyle–volsella complex. In this way, the harpe of these three specimens resemble the harpe of C. longiharpes , although they otherwise match C. abdominalis and can be easily separated from C. longiharpes by the presence of the facial sulcus.

Differences between Nearctic and Palearctic Populations. No differences were found between Nearctic and Palearctic populations.

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 recognizable by the following combination of characters: facial sulcus present; sternaulus present and elongate, exceeding 1/2 of mesopleuron length at level of sternaulus; male genitalia with 1–3 apical parossicular setae ( Fig. 10 ; prs); harpe longer than gonostipes in lateral view; harpe spatulate or spoon-shaped; and harpe oriented medially.

Similar species include C. longiharpes , which lacks the facial sulcus, and C. rosemaryae , which has the facial sulcus present but also has the dorsomedian projection of the gonostyle–volsella complex present (absent in C. abdominalis ) and harpe that are not spatulate or spoon-shaped and are shorter than the gonostipes in lateral view. Conostigmus pulchellus is also very similar to C. abdominalis but differs in that it has 4 or more apical parossicular setae (1–3 in C. abdominalis ). Also, the harpe are twisted and oriented either dorsally or dorsomedially (harpe are not twisted and are oriented medially in C. abdominalis ).

Female C. pulchellus can be distinguished from C. abdominalis by lighter yellow or reddish coloration on the anterior mesosoma, axilla and axillula (see diagnosis section of C. pulchellus ). However, C. abdominalis and C. rosemaryae can only be distinguished by male genitalia characters. Conostigmus rosemaryae is only known from the Nearctic, whereas C. abdominalis is Holarctic in distribution, but at this time, it is not possible to distinguish Nearctic females of C. abdominalis from C. rosemaryae .

Description. Color hue pattern in male: cranium, mesosoma, metasoma reddish brown to dark brown; F1–F9 light brown to brown; scape, pedicel ochre to brown; legs ochre to light brown. Color intensity pattern in male: metasoma and mandible lighter than mesosoma; flagellomeres darker than scape and pedicel; mandible lighter than cranium. Color intensity dorsal and ventral to the site of the sternaulus: concolorous. Color intensity pattern of syntergite: petiole neck and anterior region of syntergite concolorus with the posterior region of the syntergite. Foveolate sculpture on body count: absent. Rugose sculpturing count: present on head and sometimes mesosoma. Rugose region on upper face count: present.

Antennae: Male scape length vs. pedicel length: 3.8–6.0. Male scape length vs. F1 length: 0.8–1.2. Male F1 length vs. pedicel length: 3.8–7.5. Male F1 length vs. male F2 length: 1.2–1.5. 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), except in smaller specimens (PSUC_FEM 50086). Head height (HH, lateral view) vs. eye height (EHf, anterior view): HH:EHf=1.5–1.8. Head height (HH) vs. head length (HL): HH:HL=1.2–1.3. Head width (HW) vs. interorbital space (IOS): HW:IOS=1.7–1.9. Head width (HW) vs. head height (HH): HW:HH=1.3–1.5. Cephalic size (csb): Mean: 450–730 μm. Maximum eye diameter vs. minimum eye diameter: 1.1–1.4. 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=1.6–2.2. 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): 1.6–2.2:1.7–2.2:1.0. 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 sulcus present. Facial sulcus count: present. 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 does not extend across intertorular area to dorsal margin of clypeus. Median region of intertorular area shape: flat. 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=390–1175 μm. Anterior mesoscutal width (AscW) vs. posterior mesoscutal width (PscW): AscW/PscW=0.6–0.9. Mesoscutal length (MscL) vs. anterior mesoscutal width (AscW): MscL/ AscW=1.5–1.9. 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 1/2 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: absent. 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: 2.3–2.8. Shortest width of petiole neck vs. synsternal translucent patch maximum width: 2.1–2.9. Syntergal translucent patch maximum width vs. minimum width: 1.1–1.7. Synsternal translucent patch maximum width vs. minimum width: 1.2–1.7. 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 lateral to the synsternal translucent patch posterior margin; 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: straight; 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 or double transverse row of setae, sometimes with fewer setae medially to form two separate patches. 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 gonostylevolsella 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: acute. Gonocondyle count: present. Gonocondyle shape: blunt. Distodorsal margin of cupula shape: straight. Distoventral submedian corner of the cupula 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: U-shaped. 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 present and parossiculi independent or fused proximally. Apical parossicular setae count: one; two; three. Distal projection of the parossiculus count: present. 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 longer than gonostipes in lateral view. Harpe shape: simple and not bilobed; spatulate or spoonshaped. Harpe orientation: medial. Lateral margin of harpe shape: widest point of harpe is between proximal 1/3rd and 2/3rds. 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 longer than harpe width. Distodorsal setae of sensillar ring of harpe orientation: distomedially. Sensillar ring area of harpe orientation: medially. Sensillar ring shape: elongate. Distoventral margin of harpe in lateral view: convex.

Distribution. Holarctic.

Material Examined. Lectotype female: SWEDEN: NHRS-HEVA000006794 ( NHRS).

Non-type material (34 males): CANADA: 1 male. PSUC _FEM 50171 ( CNC) . SWEDEN: 10 males . IM 1585, 1741, 1718-1718; NCSU 0017731 , 0017732 , 0017745 , 0055614 , 0055635 ; PSUC _FEM 28915, 148408 ( NCSU). USA: California: 2 males . PSUC _FEM 26786 ( OSUC) ; UCRC _ ENT 00457086 ( UCRC). USA: Colorado: 1 male . PSUC _FEM 86279 ( MSUC). USA: Michigan: 2 males . PSUC _FEM 50143 ( WIRC) ; PSUC _FEM 86312 ( MSUC). USA: North Carolina: 1 male . CMNHENT0022737 ( CLEV). USA: Ohio: 1 male . CMNHENT0022804 ( CLEV). USA: Pennsylvania: 1 male . PSUC _FEM 58229 ( PSUC). USA: Tennessee: 1 male . UCFC 243668 ( UCFC). USA: West Virginia: 2 males . IM 1612; PSUC _ FEM 148575 ( NCSU). USA: Wisconsin: 12 males . PSUC _FEM 34020 ( TAMU) ; PSUC _FEM 50086, 50142 , 50154 , 50242 , 50256 , 83702 , 84006 , 84507 , 88062 , 88082 , 98426 ( WIRC) .

Figures

FIGURE 9. Conostigmus abdominalis (Boheman, 1832) males. A. Dorsal view. (PSUC_FEM 88062). B. Frons (PSUC_FEM 88082). C. Lateral (PSUC_FEM 86279). Abbreviations: facial sulcus (fs), pronotum (prn), sternaulus (ste).

FIGURE 10. Conostigmus abdominalis (Boheman, 1832) male genitalia. A. Ventral (PSUC_FEM 148450). B. Dorsal (PSUC_ FEM 148545). C. Lateral (PSUC_FEM 88175). D. Odd specimen (PSUC_FEM 50171) with harpe that are barely spatulate or spoon-shaped, resembling C. longiharpes. E. Odd specimen from Michigan (PSUC_FEM 50143) with the widest part of the harpe varying occurring in the proximal 2/3rds. F. S9 (PSUC_FEM 50154). Abbreviation: apical parossicular setae (prs).

FIGURE 16. Conostigmus californicus (Ashmead, 1893) male lectotype (USNMENT01339748), lateral habitus.