Megastigmus ozoroae Roques & Copeland

Roques, Alain, Copeland, Robert S., Soldati, Laurent, Denux, Olivier & Auger-Rozenberg, Marie-Anne, 2016, Megastigmus seed chalcids (Hymenoptera, Torymidae) radiated much more on Angiosperms than previously considered. I- Description of 8 new species from Kenya, with a key to the females of Eastern and Southern Africa, ZooKeys 585, pp. 51-124 : 75-81

Taxon classification Animalia Hymenoptera Torymidae

Megastigmus ozoroae Roques & Copeland sp. n.

Type material.

Holotype. ♀, Kenya, Nyanza Province, Sindo-Mbita Road, 0.4849°S, 34.1765°E, 1205m, 11 Dec 2004, A&M coll. N°3064, ex. Ozoroa insignis ssp reticulata, R. Copeland leg. (NMKE)

Paratypes. 8 ♀♀, same collection data as holotype; 6♂♂, same collection data as holotype, except 19 Dec 2004, A&M coll. N°3077 (2♀♀, 1♂, NMKE; 2♀♀, 1♂ RSC; 2♀♀, 1♂ ARC, 1♀, 1♂ ICIPE, 1♀, 1♂ SAMC)

Additional material examined.

23♀♀, 11♂♂ same collection data as holotype, except 19 Dec 2004, A&M coll. N°3077 (11♀♀, 5♂♂ RSC; 12♀♀, 6♂♂ ARC)

Descriprion.

Holotype ♀. Large species, body length (without ovipositor) 4.8 mm; length of ovipositor sheaths 1.5 mm. Body colour yellow and black (Figures 42-44). Head pale yellow except a conspicuous black ring around occipital carina extending on vertex in a distinct median band reaching the inter-antennal area, malar sulcus blackish, and a black dot on each side of clypeus (Figure 45). Pilosity pale on lower face; upper face with a row of long black hairs along parascrobal area and on dorsum of head (Figure 45). Antenna brown with scape and pedicel yellow beneath. Pronotum pale yellow- grey with a large, nearly rectangular, longitudinal black spot in the middle, its colour turning to brownish at the posterior end (Figure 44). Remainder of thorax mostly pale yellow with conspicuous darker patterns: a large brownish spot covering most of the mid-lobe of mesoscutum (except the lateral parts) including a large black triangle at the anterior suture extending in a median, distinct black line to the posterior suture, a large triangular brownish spot covering most of the scutellum, a rectangular orange spot on the upper part of the lateral lobe of mesoscutum followed by a grey spot of same size, a large orange spot on the axilla, all sutures brownish- black along prepectus and lateral panel of pronotum, mid-lobe of mesoscutum, lateral lobe of mesoscutum and scutellum, and a brownish oval spot including a small triangular black spot in the middle of the mesepimeron. Metanotum yellow with a black transverse line interrupted in the middle. Pilosity on thorax dark, with 5 pairs of conspicuous setae on the lateral yellow sides of the posterior part of mid-lobe of mesoscutum, 4 pairs on lateral sides of scutellum, and 1 pair of large setae at the anterior corner of axilla.

Legs pale yellow except claws brownish; coxae with numerous pale hairs extending from small black dots, especially on hind coxa; femora with small black hairs; tibiae with 3 rows of long black hairs. Forewing stigma brown without infuscation; basal cell only partly closed, the disc with 5 very small setae; basal line with 2 setae; no setae on costal line; 4 setae in coastal cell (Figure 47). Propodeum pale yellow with black markings including a large central band extending in a lateral line along the suture with metanotum (Figure 44), a longitudinal spot along suture between callus and propodeum, and the sutures of metapleuron and callus. Pilosity pale on propodeum. Gaster brown- black with yellowish sides; T3 black on dorsum; the 4 following tergites with large transverse black bands progressively narrowing and becoming brownish on sides; a row of long black hairs along lateral parts of all tergite sutures; sterna pale yel low; Ovipositor sheaths black, short, only 0.8 × as long as gaster, 0.3 × as long as body (Figure 43).

Head about 1.1 × as wide as long in front view (Figure 45). POL: OOL: 1.5; inter-antennal area as broad as torulus width; scrobe elongate, ca. 3 × as long as wide. Scape 1.2 × as long as combined length of pedicel, anellus, and F1 (Figure 46); scape 0.8 × as long as combined length of pedicel, anellus, F1 and F2; F1 1.3 × as long as pedicel, 1.7 × as long as wide; F2 1.6 × as long as wide; following funicular segments tending to subquadrate from F3, with F7 as long as wide. Pronotum with coarse transverse carinae; mid-lobe of mesoscutum and axilla with finer cross-striae; mid-lobe of mesoscutum 1.3 × as long as scutellum; scutellum 1.1 × as long as wide, noticeably covered with longitudinal, irregular wrinkles; frenum quite indistinct from scutellum, roughly 0.4 × as long as scutellum length, completely covered with irregular wrinkles. Forewing stigma oval- oblique, about 1.6 × as long as wide (Figure 47); upper part of stigmal vein elongate, 0.4 × as long as stigma length; uncus short, 0.4 × as long as upper part of stigmal vein; marginal vein 0.8 × as long as postmarginal vein. Propodeum with a short median carina in its anterior part and cross- striae on its upper part, the lower part smooth and shining.

Variation. Females range in length from 3.5 to 4.8 mm. Five of the examined specimens out of 14 have lateral lobes of mesoscutum and scutellum pale yellow. The black spots on pronotum and mid-lobe of mesoscutum as well as the other black markings are absent in one specimen, except at base of eye, on the suture of the lateral lobe of mesoscutum and on the central part of propodeum. The general colour of this specimen is orange, with the gaster brownish and not blackish in its middle part, the brownish colour beginning only at T5. Another specimen has the central part of propodeum completely shining black. The relative length of the ovipositor sheaths varies between 0.7 to 0.8 × the gaster length, and 0.3-0.4 × the body length.

Males. They are highly variable in colour, and two extreme forms can be distinguished with intermediates.

Pale form. Body length from 4.3 to 5.7 mm. Body colour pale yellow and black (Figures 48-50). Head with a large black spot extending from lower face to frons and vertex, and laterally to the lower part of eye which is entirely surrounded by a black line, and malar space (Figure 51); yellow only on gena, temples, base of clypeus and lower part of malar space and parascrobal area; ocellar area black, with anterior ocellus covered with black but not the lateral part of posterior ocelli; black extending in a conspicuous black ring around occiput. Pilosity on face pale, but conspicuous black hairs on parascrobal area, temple, gena and dorsum of head (Figure 51). Antenna yellow. Pronotum yellow with a longitudinal black band in the center, narrowing towards mid-lobe of mesoscutum. Remainder of thorax yellow, except mid-lobe of mesoscutum with a large triangular black-brown spot covering the anterior part, prolongated in its center by an irregular longitudinal black line, narrowing in the middle, and expanding to the posterior part of mid-lobe of mesoscutum (Figure 50). Anterior of scutellum with a brownish; a conspicuous square-shaped grey spot in the posterior part of lateral lobe of mesoscutum; axilla yellow; lateral panel of pronotum black; prepectus mostly black with a few yellow infuscations near the suture of lower mesepisternum and prothoracic spiracle; upper and lower mesepisternum mostly black except in the center a yellow band extending to median coxa; lateral part of upper and lower mesepimeron yellow; all sutures black along mid-lobe of mesoscutum, lateral lobe of mesoscutum, and scutellum. Thoracic ventrum mostly black. Pilosity on thorax consisting of long black hairs, including 5 pairs on the postero- lateral parts of mid-lobe of mesoscutum, 1 pair on axilla, and 3 pairs on scutellum.

Legs yellow expect anterior part of coxae with large black spots (extending to the posterior part in fore coxa), and small brownish spots at femur insertion, 3 rows of large hairs on tibia. Forewing stigma brown without infuscation (Figure 54); basal cell partly closed, with 8 setae on disc; basal setal line with 2 long setae, but costal setal line quite indistinct with 3 small setae; coastal cell with more than 20 long setae in several rows in the apical 1/2 to 2/3. Propodeum yellow- grey with a black band along the anterior suture black and a large oval black spot medially (Figure 50); callus and metapleuron yellow but the sutures black. Propodeum hairs pale. Gaster colour mostly black-brown; T3 petiolate and black; T4 with anterior part brown, followed by a large yellow band; T5 with the anterior part brown, followed by a small yellow band; T6 with a large black spot in form of shield; T7 brown; T8- T9 yellow with a brown lateral band. Long black hairs on tergite sutures. Genitalia with elongate aedeagus, its part above digitus about 1.8 × as long as digitus length; digitus compressed, about 2.2 × longer than its maximum width, with 3 teeth (Figure 53).

Head about 1.2 × as wide as long in front view. POL: OOL: 2.0; inter-antennal area as broad as torulus width; scrobe short, ca. 1.5 × as long as wide. Scape 1.3 × as long as combined length of pedicel, anellus, and F1 (Figure 52); scape 0.9 × as long as combined length of pedicel, anellus, F1 and F2; F1 1.5 × as long as pedicel, 1.7 × as long as wide; F2 1.6 × as long as wide; following funicular segments elongate, only tending to subquadrate from F7. Pronotum with coarse transverse carinae, mid-lobe of mesoscutum and axilla with transverse striae finer than on pronotum. Mid-lobe of mesoscutum 1.3 × as long as scutellum length; Scutellum 1.2 × as long as wide, noticeably covered with longitudinal, irregular wrinkles; frenum nearly indistinct from scutellum, roughly 0.4 × as long as scutellum length, completely covered with irregular, arching, concentric wrinkles. Forewing stigma oval- oblique, about 1.4 × as long as wide (Figure 54); upper part of stigmal vein very short, only 0.3 × as long as stigma length; uncus short, 0.6 × as long as upper part of stigmal vein; marginal vein 0.9 × as long as postmarginal vein. Propodeum with strong, irregular striae medially

Dark form. Larger than pale form, with body length 5.0 to 6.5 mm. Body colour mostly black (Figures 55-57) with a conspicuous, large triangular infuscation around the forewing stigma (Figure 61). Head entirely black except a triangular dark grey spot along parascrobal area (Figure 58). Thorax black except a triangular grey spot on sides of pronotum posteriorly, a narrow yellowish line on the sides of mid-lobe of mesoscutum and on lateral sutures of lateral lobes of mesoscutum, axillae yellowish (Figure 57). Antero-lateral part of scutellum yellowish but frenum black. Metanotum with a transverse yellow line. Propodeum entirely black. Legs mostly black (Figure 56); coxae black except the posterior part yellowish; mid- and hind femora black except the basal and apical part brownish; fore femur with the apical part yellow; tibiae and tarsi yellow. Forewing with basal cell closed, disc with 10 strong setae; basal setal line with 2 long setae, costal setal line with 8 small setae; coastal cell with more than 100 small setae in several rows in the apical 1/2 to 2/3 (Figure 61). Thoracic sculpture, pilosity and genitalia (Figure 60) same as in pale forms.

Intermediates. In some specimens, black patterns on thorax are limited to a sharp median line on pronotum and mid-lobe of mesoscutum, and to the sutures of lateral panel of pronotum, prepectus, and tegula. These specimens also show a grey spot on lateral lobes of mesoscutum and a brownish median line on scutellum. Gaster is mostly black with a few yellow patterns as follows: an annelation at the base of T3, the sides of T4, a small lateral spot on T5 and the last two segments. Forewing stigma not infuscated in these individuals. In some others, the lateral parts of thorax are black (panel of pronotum, prepectus, mesepisternum, and upper mesepimeron) except lower mesepimeron and metapleuron and callus yellow (with black spots on callus), and scutellum is black at the base with the remainder dark brown. In these individuals, the forewing stigma is infuscated. Pilosity may include 5-6 pairs of setae on mid-lobe of mesoscutum and 3-4 pairs on scutellum.

Host plants.

Ozoroa insignis ( Anacardiaceae ). Its position in the molecular phylogeny is close to those Megastigmus species known to be seed feeders in Anacardiaceae , strongly suggesting it is also a seed feeder. Although the presence of numts was noticed in the analyzed specimen of Megastigmus ozoroae it belonged whatever the marker (short mitochondrial or nuclear fragment) to the " Anacardiaceae clade" confirming the existence of a strong monophyletic clade, the most divergent from the others (Figure 14).

Distribution.

Known only from western Kenya, near Lake Victoria. In one collection, 8.1% of fruits were infested (Table 3).

Etymology.

Named after the genus of the host plant.

Diagnosis.

Females are easily distinguished from those of other species observed to emerge from fruits of Anacardiaceae by the relatively small ovipositor, nearly as long as gaster length whereas it is at least 1.2 × the gaster length in Megastigmus hypogeus (Figure 117), Megastigmus lanneae (Figure 97), Megastigmus laventhali (Figure 76), Megastigmus pistaciae (Figure 137), Megastigmus thomseni (see Hussey 1956a) and Megastigmus transvaalensis (Figure 151). In contrast, the ovipositor of Megastigmus smithi is significantly shorter (0.4 × the gaster length; Figure 31). Genitalic characters differentiate male Megastigmus ozoroae from those of males described for other species that feed in Anacardiaceae ; the aedeagus part above digitus being significantly longer in Megastigmus ozoroae (1.8 × as long as digitus length) than in Megastigmus hypogeus (1.2 –1.3×; Figures 127, 134), Megastigmus pistaciae (0.8 ×; Figure 148) and Megastigmus transvaalensis (0.5 ×; Figure 162). The aedaegus dimension compared to digitus is similar in Megastigmus lanneae but the phallobase is more elongate in the latter species (Figures 107, 115), being 2.8 × longer than wide vs. 2.6 × in Megastigmus ozoroae .