Afrotremex violaceus ( Pasteels, 1951 )

Goulet, Henri, 2014, Revision of the African horntail genus Afrotremex (Hymenoptera: Siricidae), Zootaxa 3795 (3), pp. 201-254 : 242-246

6. Afrotremex violaceus ( Pasteels, 1951)

Fig. T6.1 (female habitus); K12, K17, K20, K23, K24a, K25, K27, K29, K31, K33 (keys); T1.9, T1.10, T1.11, T1.23, T5.8, T6.2–T6.8 (description).

Map (T1.26), blue triangle

Afrotremex violaceus Pasteels, 1951: 196–197 . Holotype female (MRAC) examined, right middle leg above coxa, left hind leg above coxa, and ovipositor missing, and labelled: [Red] " HOLOTYPUS violaceus Past."; [White] "Coll. Mus. Congo Mayidi 194 5 Rév. P. Van Eyen"; [White] "R. DET. X. 5515"; [White] " Type "; [White] " Afrotremex ♀ violaceus n. sp. J. Pasteels det., 1950". Name accepted by Smith 1978: 90 (catalog), Taeger et al., 2010: 106; and Taeger, and Blank 2011.

I studied two female paratypes from Mayidi and Bas Congo (Lemfu). Pasteels reported six females altogether from Mayidi (one holotype and three paratypes captured in 1942 and 1945) and Bas Congo (Lemfu) (two paratypes captured in xii. 1945) .

Diagnosis. Among species with concave outlined lateral edge of submedian band in posterior 0.5 ( A. pallipennis ), adults of A. violaceus are distinguished from those of A. pallipennis by the absence of a longitudinal row of large pits (about 0.25 times as large as diameter of lateral ocellus) along the middle line in anterior 0.3 of median band, and in female, by the completely darkly tinted fore and hind wings.

Comparative diagnosis. Afrotremex violaceus is most similar to A. pallipennis . It is unique in the following three features: absence of a median row of pits on the anterior 0.3 of the median band of mesoscutum; darkly tinted fore and hind wings; and extent and position of the shiny surface on terga 4–8.

Afrotremex violaceus shares with A. pallipennis the following twelve features: a row of fused pits in lower 0.5 of gena; size of the sensory oval on the inner surface of flagellomere 2; relative size of the median band at its narrowest; number of pits on the anterolateral corner of the lateral band of mesoscutum; width of the lateral extension of small pits of the mesoscutal median band posterior to submedian band; presence of widespread sculpticells in the scutoscutellar furrow; size of the shiny surface on tergum 8; absence of microsculpture around pits on most of the surface above the lateral longitudinal furrow of tergum 9; absence of pitted sculpticells between pits on the dorsal surface of tergum 10; distribution of pits on tergum 10; distribution of teeth along lateral surface posterior to the lateral tooth of tergum 10; and width an length of the pit on annulus 2 of the ovipositor.

Afrotremex violaceus is distinguished from A. pallipennis by all the unique attributes mentioned above and the following five features: extent of the pit density on the vertical lateral surface of pronotum; absence of a median row of large pits in the anterior 0.3 of the median band of mesoscutum; color pattern of the pro- and mesotrochanters in apical 0.3; extent of the clear pattern of the fore and hind wings; and position and extent of shiny surfaces on terga 4–8.

Afrotremex violaceus is distinguished from A. hyalinatus by all the unique attributes mentioned above and the following twelve features: density and size of pits on gena; shape of the apex of setae and their relative length on clypeus, frons and postocellar area; size of sculpticells on the dorsal surface of the pronotum between shiny teeth; sculpticell distribution on the anterior 0.3 of the median and submedian bands of mesoscutum; sharpness of the lateral edge of the submedian band of mesoscutum, convergence of its edge in anterior and posterior 0.5, and curvature of its edge in posterior 0.5; width of the pitted surface of the median band of mesoscutum extended laterally posterior to submedian band; size and number of shiny teeth on axilla; absence of pits similar in size to those of the median band of mesoscutum on anterior edge of axilla; position and extent of shiny surfaces on terga 5–8; extent of shiny surface along the median area anteriorly on tergum 8; median ridge prominence in the median basin of tergum 9; density and size of pits on sterna 2–6; and length and width of pits on annuli 2 and 10 of the ovipositor.

Afrotremex violaceus shares with A. hyalinatus the following nine features: a row of fused pits in lower 0.5 of gena; size of the sensory oval on the dorsal surface of flagellomere 2; relative width of the median band at its narrowest; number of pits anterolaterally on the lateral band of mesoscutum; extent of sculpticells in the scutoscutellar furrow; lateral extension of pits of the median band of mesoscutum posterior to submedian band; absence of microsculpture around most pits above the lateral longitudinal furrow on tergum 9; absence of pitted sculpticells in pits on the median dorsal surface of tergum 10; distribution of pits on dorsal surface of tergum 10; and length of pit on annulus 2 of the ovipositor.

Afrotremex violaceus is distinguished from A. xylophagus by all the unique attributes mentioned above and the seven following features: organization of pits in a row along a line between the lower eye margin and the occiput, and sculpture at the bottom of these pits; sharpness of the outline of the lateral edge of the submedian band of mesoscutum, and curvature of its edge in posterior 0.5; width of the pitted surface of the median band of the mesoscutum extended laterally posterior to submedian band; extent and position of the shiny surface on terga 4–8; extent of shiny surface along the median area anteriorly on tergum 8; median ridge prominence in the median basin of tergum 9; and distribution of pits anteriorly on tergum 10.

Afrotremex violaceus shares with A. xylophagus the following eight features: size of the sensory oval surface on the dorsal surface of flagellomere 2; relative width of the median band at its narrowest; lateral extension of the median band pits posterior to submedian band; number of pits anterolaterally on the lateral band of mesoscutum; presence of widespread sculpticells in the scutoscutellar furrow; absence of microsculpture laterally on tergum 8; absence of pitted sculpticells in and around pits on median dorsal surface of tergum 10; and size of the pit on annulus 2 of the ovipositor.

Afrotremex violaceus is distinguished from A. comatus and A. opacus by all the unique attributes mentioned above and the following eleven features: organization of pits in a row along a line between the lower eye margin and the occiput and presence of microsculpture at the bottom of these pits; size of sensory oval on the dorsal side of flagellomere 2; sharpness of the outline of the lateral edge of the submedian band of mesoscutum, and curvature of the its edge in posterior 0.5; width of the median band of the mesoscutum at its narrowest; lateral extension of fine pits of the median band of mesoscutum extended laterally posterior to submedian band; number of pits on the anterolateral corner of the lateral band of mesoscutum; extent of microsculpture on the scutoscutellar furrow; extent and position of the shiny surface on terga 5–8; pitted sculpticells in and around pits on most of the surface of tergum 9 above the lateral longitudinal furrow; distribution of pits along the anterior surface of tergum 10; extent of pitted sculpticells on the dorsal surface of tergum 10; and length and width of the pit on annulus 2 of the ovipositor.

Description of female. COLOR. Fore and hind wings darkly tinted with a purple hue (may be difficult to see) in all cells (Fig. K33). Protrochanter and mesotrochanter ventrally in apical 0.3 black or somewhat paler.

HEAD. Gena with large pits forming a curved row (row including some pits laterally) between lowest eye edge to occiput, the pits fused completely and bottom of each pit with irregular fine ridges (Fig. T1.23); the remaining surface with pits larger (0.2–0.3 times as large as lateral ocellus) and quite dense in ventral 0.5, and scattered in dorsal 0.5 and small (at most 0.15 times as large as lateral ocellus) and less dense (Fig T1.23, T6.5 and T6.6). Setae on clypeus, frons and postocellar area truncate or very slightly enlarged apically (about 1.5 times as wide as setal shaft or truncate), and on frons 1.5–2.0 times as long as diameter of lateral ocellus (Fig K14 and as in T1.24, insert). Pedicel about 0.9 times as long as wide (as in Fig. T1.4). Flagellomere 2 with sensory oval covering about 0.5 of dorsal surface (as in Fig. K1).

THORAX. Pronotum with vertical lateral surface very densely pitted in posterior 0.5 (Fig. T6.3); dorsal surface around shiny teeth with very short ridges changing into deep and dense pits, the pits with irregularly defined edges (worm-like) of various heights and about 0.1 as large as diameter of lateral ocellus (Fig. T6.2); in lateral view, dorsal surface without or with some very short setae (as in Fig. K46). Mesoscutum with median band generally finely sculptured, widest anteriorly, at its narrowest the band about 0.7 times as wide as diameter of lateral ocellus (Fig. K17); pits without microsculpture at bottom, very deep, their edges irregularly defined (wormlike), and 0.15–0.2 times as large as diameter of lateral ocellus, without large pits along middle line in anterior 0.3 (Fig. K24a), and with pits becoming smaller (at most 0.1 times as large as diameter of lateral ocellus) in posterior 0.5 and extended laterally posterior to submedian band (Fig. K17 and as Fig. 3a). Submedian band in anterior 0.1–0.3 without pitted sculpticells within pits; lateral edge sharply outlined and convergent in anterior 0.5, and convergent and clearly concave in posterior 0.5 (as in Fig. K16). Lateral band shiny with many pits (>10) fused on anterolateral corner (as in Fig. K4a). Scutoscutellar furrow with convex sculpticells (sculpticells clearly with metallic hue) over all of central surface (as in Fig. K3a). Axilla with large scallop-like pits similar to those on submedian band but somewhat smaller, not connected with small pits from submedian band along edge anteromedially (some wrinkles present), and without small pits (similar to those of median band) along anterior margin (Fig. K17).

ABDOMEN. Terga 1–5 with deeply pitted sculpticells (surface matt). Terga 6–8 with shiny areas (microsculpture meshes absent or very lightly impressed). Tergum 6 shiny in posterior 0.5 medially; tergum 7 shiny in posterior 0.7 medially with a short anterior extension medially (Fig. K25); and tergum 8 shiny in posterior 0.7 with a short anterior extension medially (Fig K23 and K27). Tergum 9 with median basin bearing about 20 crescent-shape tubercles on each side on central portion, each tubercle with or without seta posteriorly, and the seta when present as small as size of shiny tubercle; longitudinal median ridge in median basin outlined but not prominent, suggested posteriorly, or absent; median basin without a small shiny central spot; median basin slightly longer than wide (maximum width/ maximum median length: 0.90–1.00) (Fig T1.9 and T6.7). Tergum 9 in lateral view above longitudinal furrow (only surface with setae at center) in ventral 0.5 with clearly outlined pits, pits smooth at bottom and surface smooth between pits, in dorsal 0.5 pits distinctly or indistinctly outlined with pitted sculpticells at bottom and surface smooth between most pits (as in Fig. T6.4). Tergum 10 in dorsal view narrowly pitted (about 0.75 times as wide as posterior width of median basin of tergum 9); each pit shiny at bottom (surface between pits shiny); pits extended medially to but not reaching anterior posterior edge of median basin (Fig. K29); lateral surface posterior to lateral tooth shiny and without large teeth (Fig. K20); surface anterior to lateral tooth with distinctly outlined pits partly bordered by shiny ridges, each pit large and with pitted sculpticells at bottom (Fig. K31). Ovipositor annuli 2 and 10 each with one wide pit as long as annulus (as in Fig. T5.7, base and Fig. T6.8); each pit clearly folded dorsally and sharply ventrally, and hardly tapering anteriorly.

Taxonomic notes. Pasteels (1951) distinguished this species from A. hyalinatus , the only species known to him, only on the color pattern of the fore and hind wings.