Scelio taylori Nixon

Yoder, Matthew J., Valerio, Alejandro A., Polaszek, Andrew, Noort, Simon van, Masner, Lubomir & Johnson, Norman F., 2014, Monograph of the Afrotropical species of Scelio Latreille (Hymenoptera, Platygastridae), egg parasitoids of acridid grasshoppers (Orthoptera, Acrididae), ZooKeys 380, pp. 1-188 : 40-45

Scelio taylori Nixon Figures 8, 97-114; Morphbank 33

Scelio taylori Nixon, 1958: 313 (original description, keyed); Masner 1965: 95 (type information).

Description.

Female body length: 3.16-4.73 mm (n=42). Male body length: 3.20-5.10 mm (n=37). Shape of compound eye: not or only slightly bulging. Color pattern of pilosity below anterior ocellus in female: brown throughout. Sculpture of frons in female: reticulate rugose, rugae somewhat thickened, without dorsoventral trend. Genal carina in female: present. Width of gena in lateral view: weakly expanded, posterior margin parallel to posterior margin of eye. Density of genal setae: sparse, setae generally inconspicuous. Color of genal setae: white to off-white; distinctly brown. Sculpture of base of mandible in female: minutely reticulate. Color of A1 in female: yellow throughout; light to dark brown throughout, or with apex and base slightly lighter, often yellowish. Color of A3 in female: brown. Sculpture of dorsal pronotal nucha in female: predominantly to completely sculptured. Color of pilosity of pronotal shoulder in female: predominantly white to off-white; predominantly light brown to brown. Sculpture along humeral margin of mesoscutum: well-defined throughout. Color of pilosity of mesonotum in female: predominantly light to dark brown. Transition from lateral to posterior margin of propodeum in dorsal view: forming distinct angle, corner of propodeum well defined. Shape of mesoscutum in lateral view: bulging in anterior third. Pilosity on metapleuron above hind coxa: glabrous or with few scattered setae. Form of fore wing submarginal vein in female: nebulous at or just before upcurve to marginal vein, not reaching margin as a tubular vein; tubular throughout from base to costal margin. Fine pilosity of lateral T1 in female: absent. Width of metasoma: moderately wide, width of S3 1.5-1.6 times medial length. Distribution of pilosity on T2-T5 in female: more or less evenly distributed throughout. Sculpture of T3 in female: longitudinally striate throughout. Overall sculpture of S3: with dense, fine longitudinal carinae. Sculpture of medial S3 in female: present throughout; with broadly obliterated or with distinct smooth patch.

Diagnosis.

Most similar to Scelio albatus which also has the genal carina well developed. Easily distinguished from Scelio albatus by the color of the pilosity (completely white in Scelio albatus ), robustness of sculpture (finer, more compact in Scelio albatus ) and, for most individuals, the color of the scape (dark brown in Scelio albatus , yellow to light brown in nearly all Scelio taylori ).

Link to distribution map.

http://hol.osu.edu/map-large.html?id=5342

Material examined.

Holotype, female: UGANDA: Toro, IV-1941, T. H. C. Taylor, B.M. TYPE HYM. 9.538 (deposited in BMNH). Paratype: UGANDA: 1 female, BMNH(E)#790423 (BMNH). Other material: (58 females, 39 males) BENIN: 3 females, 4 males, OSUC 211370, 212290, 491191 (CNCI); OSUC 142656, 142658, 142664, 142666 (OSUC). CAMEROON: 8 females, OSUC 211220-211221, 211399, 212114, 212125, 212259, 212261, 212898 (CNCI). CENTRAL AFRICAN REPUBLIC: 3 females, 5 males, OSUC 213971 (OSUC); OSUC 176092, 212400, 213533, 213925, 214187, 214197 (SAMC); OSUC 250667 (SANC). GABON: 1 female, OSUC 213128 (CNCI). GHANA: 1 female, OSUC 213563 (OSUC). IVORY COAST: 4 females, OSUC 211274, 213060, 213078, 213227 (CNCI). KENYA: 16 females, 22 males, OSUC 212506, 214083, 214088-214090, 214096, 214098-214100, 214117, 214119, 214121, 214123, 214125, 214127-214131, 214133, 214180, 234635, 234649, 234651-234652, 234654-234656, 234658-234659, 234692-234694, 234697-234698, 250821 (CNCI); OSUC 244089, 244093 (USNM). MA LAWI: 3 females, OSUC 212744, 212799, 213138 (CNCI). NIGERIA: 12 females, 4 males, OSUC 202815, 202817 (AEIC); OSUC 211379, 211682, 212175, 212629-212630, 212694, 212700, 212801, 212803, 213025, 213140, 213142, 213180, 213279 (CNCI). SIERRA LEONE: 1 female, 1 male, OSUC 244058, 244061 (MZLU). TANZANIA: 1 female, OSUC 212513 (CNCI). UGANDA: 1 female, 2 males, OSUC 212931, 213021 (CNCI); OSUC 244070 (USNM). ZIMBABWE: 4 females, 1 male, OSUC 212201, 212209, 212212, 212827, 212923 (CNCI).

Comments.

As delimited here Scelio taylori is a widespread and somewhat polymorphic species. At times we considered the material to represent upwards of four species. However, as limits among those concepts blurred, we have elected to take a conservative approach to delimiting this taxon. When comparing opposite extremes (e.g., OSUC 212801 in Figs 97-102 and OSUC 213533 in Figs 109-114) there appears to be clearly differentiable species. However, intermediate series (such as OSUC 213180 IN Figs 103-108) are problematic. The concept of Scelio taylori broadly encompasses three core groups: 1) a larger series (to which the type belongs) of slightly smaller individuals, relatively easily diagnosed by the white setae of the gena (Figs 97-102); 2) a series of specimens similar to 1), but darker overall, with the pilosity of the head, pronotal shoulder and lateral T2 brown (Figs 103-108); and 3) four larger, darker (pilosity, body color, wing infuscation) specimens (Figs 109-114). A small series of intermediates blurs the line between 1 and 2, and contains several singletons that may represent additional morphotypes. The three groups are largely geographically separated, series 1 is widespread across central Africa (but absent in South Africa), series 2 is found in eastern Africa (Kenya, Uganda, and possibly Tanzania), and series 3 is from Central African Republic (with one similar specimen from Cameroon). The intermediate specimens are known from Malawi, Nigeria, Ghana, and Ivory Coast.

The pilosity of T1 laterally is relatively reduced, with 4-6 setae typically present along the ventral margin. This is the only species of Afrotropical ernstii-group to exhibit truly brown setae on lateral T2, the gena, and throughout the frons (this mostly restricted to individuals of series 2).

Preliminary concepts were based on the following characters: scape color (yellow, light-brown, brown), color of pilosity of the gena (white, light brown to brow), apparent size (small to moderate, large), sculpture of the mesoscutum (moderately sized polygonal cells, large polygonal cells), infuscation of the wing (infuscation reduced to absent around submarginal, marginal, and stigmal veins and elsewhere, infuscation present more or less throughout), form of the submarginal vein near junction with marginal vein (obliterated and nebulous, tubular throughout), form of the stigmal vein (more or less obliterated, well developed tubular and sometimes slightly concave). We now interpret these states as representing a continuum of morphological variation.

While the combination of yellow scape and white pilosity holds for all specimens of group 1, and most specimens of group 2 have light brown scape and brown pilosity on the gena, there are also specimens (intermediates) with brown pilosity on the gena and a yellow scape. Of the two females in group 3 one has a dark brown scape (as does the specimen from Cameroon) and one has a bright yellow scape. The first series, the smallest individuals, all appear to have slightly larger cells on the mesoscutum (compare Figs 99 and 111). Most individuals of the second series have a similar pattern of obliteration of sculpture on the medial metasomal sternites, though this is approached in some of the first series. Individuals of the second series also have the infuscation around the submarginal and stigmal veins reduced, the submarginal vein is nebulous near the marginal vein, and the stigmal vein more or less absent, however these states are also seen in some individuals of the first series. Series three individuals have the wing strongly infuscate throughout and a strongly developed stigma and marginal vein (that has a slight hook), but these states are also observed in some of the “intermediate” specimens. Two specimens from Nigeria (intermediates) have a very slight longitudinal trend to the sculpture of the mesoscutum. Larger specimens tend to have the metasomal 3-5 sculptured throughout medially, while most individuals of the series two, and some of series one have a pattern of obliteration posteromedially on each tergite (particularly noticeable on S3, S4).

All determinations of males are tentative, most have a reduced but identifiable genal carina.