Afrotremex opacus, Goulet, 2014

Goulet, Henri, 2014, Revision of the African horntail genus Afrotremex (Hymenoptera: Siricidae), Zootaxa 3795 (3), pp. 201-254 : 233-237

4. Afrotremex opacus n. sp.

Fig. T4.1 (female habitus); K2, K46, K48, K50, K52 (keys); T1.4, T1.24, T4.2–T4.8 (description).

Map (T1.26), blue circle

Type material. Holotype female ( MRAC) ovipositor above annulus 11 missing, labeled [White] “Musée du Congo, [ Democratic Republic of the Congo] Haut Uelé: Moto 1920 L. Burgeon "; [White] " R. Det., DD 3284" [White] “ Afrotremex ♀ hyalinatus Mocs. J. Pasteels det., 19 50 ”; [Red] “ HOLOTYPE Afrotremex opacus ♀ H. Goulet, 2013 ”.

Paratype. 1 female. Democratic Republic of the Congo: Haut Uelé : Moto (1 F, MRAC) .

Diagnosis. Among species with few pits (<10) usually isolated on anterolateral corner of lateral band ( A. comatus ), adults of A. opacus are distinguished from those of A. comatus by the absence or the presence of few very small setae on medial surface of the pronotum (best seen in lateral view).

Comparative diagnosis. Afrotremex opacus is most similar to A. comatus . It is unique in following two features: absence of long and numerous setae on pronotum; and tinted color pattern on the basal lobe and tip of the hind wing.

Afrotremex opacus shares with A. comatus the following nine features: row of isolated and shiny pits in lower 0.5 of gena; size of the sensory ventral surface on flagellomere 2; relative width of the median band of mesoscutum at its narrowest; number of pits on the anterolateral corner of the lateral band of mesoscutum; lack of or very restricted presence of sculpticells in the scutoscutellar furrow; extent of pitted sculpticells on tergum 8; extent of pitted sculpticells in and around pits above the lateral longitudinal furrow on tergum 9; extent of pitted sculpticells around and in pits on anterior 0.25 of dorsal surface of tergum 10 (including surface anterior to the lateral tooth); size and shape of the pit on annulus 2 of the ovipositor.

Afrotremex opacus is distinguished from A. comatus by all the unique attributes mentioned above and the following two features: extent of the tinted surface on anal lobe of hind wing; proportion of the median basin of tergum 9; and size of pit and its ventral fold on annulus 10 of the ovipositor.

Afrotremex opacus is distinguished from A. hyalinatus by all the unique attributes mentioned above and the following nine features: density and size of pits on gena; shape of the setae at their apex and their relative length on clypeus, frons and postocellar area; size of the microsculpture on the dorsal surface of pronotum between shiny teeth; distribution of sculpticells on anterior 0.3 of median and submedian bands; the number of shiny teeth centrally and pit size along the anterior margin of axilla; extent of the shiny surface on terga 6–8; prominence of the median ridge in the median basin of tergum 9; density and size of pits on sterna 2–6; and length and width of the pit on annulus 2 of the ovipositor.

Afrotremex opacus is distinguished from A. xylophagus by all the unique attributes mentioned above and the following eleven features: proportion of the pedicel; size of sensory oval on dorsal side of flagellomere 2; density and size of pits on gena; shape of the setae at their apex and their relative length on clypeus, frons and postocellar area; width of the median band of the mesoscutum at its narrowest; absence of the lateral extension of fine pits of the median band at posterior end of submedian band; number of pits on the anterolateral corner of the lateral band of mesoscutum; distribution of microsculpture on the scutoscutellar furrow; color of the fore and hind wings; extent of pitted sculpticells on terga 6–8; distribution of pitted sculpticells in and around pits on the surface just above the lateral longitudinal furrow of tergum 9; distribution of pits and pitted sculpticells along the anterior surface of tergum 10 (including surface anterior to the lateral tooth); and size and outline of the pit on annulus 2.

Afrotremex opacus shares with A. xylophagus the following feature: density of pits with raised posterior edge in a row between lower eye margin and occiput and the sculpture at the bottom of these pits.

Afrotremex opacus distinguished from A. violaceus and A. pallipennis by all the unique attributes mentioned above and the eleven following features: distribution and organization of pits in a row along a line between lower eye margin and occiput, and microsculpture at the bottom of these pits; size of sensory oval on the dorsal side of flagellomere 2; width of the median band of mesoscutum at its narrowest; sharpness and lack of curvature of the lateral edge of the submedian band of mesoscutum in basal 0.5; lack of lateral extension of fine pits of the median band of the mesoscutum posterior the submedian band; number of pits on the anterolateral corner of the lateral band of mesoscutum; distribution of microsculpture on the scutoscutellar furrow; color pattern of the fore and hind wings; extent of the shiny surface on terga 5–8; distribution of pitted sculpticells in and around pits above the lateral longitudinal furrow on tergum 9; distribution of pits and pitted sculpticells along the anterior 0.25 of tergum 10 (including the surface anterior lateral tooth); extent of teeth along lateral margin of tergum 10 posterior laterobasal tooth; and the size and outline of pit on annulus 2 of the ovipositor.

Description of female. COLOR. Fore wing darkly tinted with a dark purple hue (may be difficult to see) in the following cells (cells codes as in Fig. M1): C, R. 1Cu, 1A (except for clear spot in apical 0.1), 1M (spot in basal 0.5), 2Cu (small spot in basal corner), 1R1, Rs+1Rs2 (spot narrow along 1R1, and in apical 025 along cell 3R1, or more widely in cell), 2R1, 3R1, 3M (spot in apical 0.7), and 3Cu (along margin); apical 0.2 of wing lightly but clearly tinted, the remaining cells clear (Fig. K52). Hind wing darkly tinted with a dark purple hue (may be difficult to see) in the following cells (cells codes as in Fig. M1): C, R (spot in basal 0.3), 1Cu1 (spot in basal 0.25), most of anal lobe (except for small clear spot anteriorly), R1 (apical 0.3 along margin), 2Rs (apical 0.3 along margin), and margin at apex of 2M; the remaining cells clear (Fig. K52). Protrochanter and mesotrochanter ventrally in apical 0.3 black or somewhat paler.

HEAD. Gena with large pits forming a curved broad furrow between lowest eye edge to occiput, the pits isolated and bottom of each pit shiny (Fig. T1.24); the remaining surface with pits more dense near mandible and scattered above, pits in ventral half 0.2–0.4 times and in dorsal half 0.1–0.2 times as large as lateral ocellus (Fig. T1.24). 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. T1.24, insert and as in Fig. K14). Pedicel about 0.9 times as long as wide (Fig. T1.4). Flagellomere 2 with sensory oval covering less than 0.2 of dorsal surface (Fig. K2).

THORAX. Pronotum with most of vertical surface very densely pitted (Fig. T4.3); dorsal surface around major shiny teeth with some radiating small ridges with some coarse pits or with large ridges and no pits (Fig. T4.2); in lateral view, dorsal surface without long setae 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 0.2 times as wide as diameter of lateral ocellus (Fig. T4.7); with pitted sculpticells in anterior 0.1 (as in Fig. T2.3), with pits present posterior to microsculptured area, pits small (at most 0.15 times as large as diameter of lateral ocellus), with shiny bottom, and not extending laterally posterior to submedian band (Fig. T4.7 and as in Fig. K3b). Submedian band in anterior 0.1–0.3 without pitted sculpticells within pits; band not sharply outlined along lateral edge (Fig. T4.7); lateral edge in anterior 0.5 convergent, and in posterior 0.5 convergent (Fig. T4.7). Lateral band shiny with few pits (<10) usually isolated on anterolateral corner (Fig. T4.7 and as Fig. K4b). Scutoscutellar furrow without sculpticells (Fig. K3b and T4.7). Axilla with large, scallop-like pits similar to those on submedian band but somewhat smaller (Fig. T4.7), not connected with small pits from submedian band along edge anteromedially (Fig. K3b), and without small pits (similar to those of median band) along anterior margin (Fig. K3b, only small portion visible).

ABDOMEN. Terga 1–5 with deeply pitted sculpticells (surface matt) except for very narrow shiny transverse band along anterior median margin of tergum 2 (maybe covered by tergum 1). Terga 6–7 without or with shiny areas present than on less than 0.15 of submedian area along posterior margin (Fig. K48); and tergum 8 without shiny surface (Fig. T4.6). Median basin of tergum 9 with about 20 shiny tubercles on each side on central portion; each tooth with or without a setae; setae when present posterior to tooth about as long as size of tubercle; longitudinal median ridge outlined but not prominent, suggested posteriorly, or absent; without a small shiny central spot; maximum length slightly wider than long (maximum width/ maximum median length: 1.05–1.08) (Fig. K50). Tergum 9 in lateral view above longitudinal furrow (in section with setae) without pits instead with numerous crescent-like tubercles, each shiny tubercle anterior to a seta surrounded by pitted sculpticells (as in Fig. T4.8, insert). Tergum 10 in dorsal view widely pitted (Fig. T4.4); each pit with some pitted sculpticells (surface between pits with pitted sculpticells except for prominent teeth); pits extending widely to anterior edge (about 0.7–0.8 of median basin posterior edge) (as in Fig. K10); tergum in lateral view with some microsculpture and shallow pits, and with many large teeth (Fig. T4.5); surface anterior to lateral tooth without distinct pits but with pitted sculpticells (Fig. T4.5). Ovipositor with annulus 2 very small (about 0.2 times as long as annulus 2), extending as a very narrow furrow to edge of annulus 1 (as in Fig M5, base and T2.7, base); annulus 10 with pit sharply outlined ventrally on about along 0.4–0.5 of annulus length; surface anterior to pit outlined by convergent round folds forming a flat surface or very shallow trough extended to anterior annulus; annulus without a long sharp ridge immediately ventral to pit (as in Fig M5, middle and T2.7, middle).

Taxonomic notes. Afrotremex opacus has been confused with A. hyalinatus probably because of the wing color pattern. Guiglia (1937) noticed marked difference in sculpture on the head and the abdominal terga between the holotype of A. hyalinatus and the two specimens from Moto. She chose to retain these specimens under the name A. hyalinatus . Pasteels (1951) saw these two specimens and accepted Guiglia’s conclusion without additional comments.

Origin of specific epithet. From Latin meaning “dark” referring to the matt surface of abdominal terga 1–9.