Megischus anaxeus Aguiar, 2006

Aguiar, Alexandre P., 2006, The Stephanidae (Hymenoptera) of Mexico, with description of six new species and key to western Foenatopus Smith, Zootaxa 1186, pp. 1-56 : 17-20

Megischus anaxeus Aguiar , sp. n.

( Figs 9–16 , 51–59 )

Etymology Greek anaxeo, hew smooth, polish; in reference to the polished interfoveolar area.

Description

FEMALE. Holotype specimen. Body length 23.3 mm. Head: Antenna with 43 flagellomeres. Frons concentrically strigate, from transverse ventrally to oblique dorsally, the carinae strong and sharp, running approximately in a zig­zag pattern, the space between them polished; centrally a few scattered hairs, decumbent upwards; along eye margins with short hairs decumbent towards center; latero­ventrally with short hairs decumbent towards clypeus. Coronal area with an elongate oval carina encircling central ocellum, and some 13 strong, short carinae radially or longitudinally extending around oval area, towards margin of coronal area. Vertex ( Fig. 51 ) nearly glabrous; three distinct sculpture patterns: anteriorly with three slightly arcuate, concentric, progressively smaller carinae; laterally areolate­rugose; centrally and posteriorly transversally strongly strigate, disappearing near occipital carina, leaving a narrow polished area; central impression absent; temple broadly polished; gena ( Figs 51, 52 ) in dorsal view weakly prominent; mostly polished, but with small, shallow foveolation with associated hairs. Occipital carina as a narrow blade, somewhat reflected towards head surface ( Fig. 51 ); dorsal portion centrally slightly projected, therefore widest at this point; ending at base of hypostomal carina; laterally and dorsally with row of equidistant, fine, long hairs along its length ( Fig. 54 ). Hypostomal area polished, except for a few very small isolated hairs.

Mesosoma: Prosternum ( Fig. 53 ) with weak pre­apical depression; mostly polished, with widely separated small foveolae. Pronotum: colo laterally with 4 pairs of wide, bladelike carinae, dorsaly widely polished, the carina widely interrupted (as in Fig. 54 ), larger towards base, the last one strongly curved inside pronotal fold. Pronotal fold very large, deeply excavate, inside and centrally with a vertical carina; its margin strongly reflexed outwards (as in Fig. 54 ). Preannular coarsely transversely rugose; the rugosity somewhat straight, polished. Femoral impression wide, smooth; ventral area gradually shifting from anteriorly obliquely carinate to posteriorly almost longitudinally rugulose and punctate. Semiannular dorsally and laterally sparsely foveolate, the foveolae larger dorsally, separated by about their diameter, each one bearing a long, thin hair; surface in between polished. Mesoscutum median sulcus distinct, notaulus somewhat indistinct, both indicated by deep, aligned foveolae; lateral lobes transversely rugose and foveolate. Axilla lateral margin taken by deep, coalescent foveolae, posteriorly and mesally with a few well defined, subcircular foveolae, centrally polished. Scutellum mostly polished, marginally with some well defined subcircular foveolae, its lateral angle deeply excavate, as a widened continuation of the deep crenulation between axilla and scutellum, this area also distinctly pilose. Mesopleuron with moderately dense foveolation, the foveolae small or medium­sized, separated by about their diameter, each bearing one long, thin hair; surface in between polished. Mesopseudosternum taken by same foveolation and pilosity of mesepisternum, except polished near discrimen, which is densely and fully crenulate. Propodeum ( Fig. 60 ) mostly taken by medium­sized, circular, well defined foveolae, apparently uniformly distributed, but in fact more or less arranged in series of 3–5 very near to each other, leaving some empty, polished spaces in between, the foveolae also polished inside; posteriorly with about four, strong, transverse, parallel rugosities near petiolar foramen, laterally, behind spiracle, changing to areolate­rugose, almost completly obliterating parapetiolar fovea. Spiracular groove and carina ( Fig. 58 ) mostly indistinct, indicated by dense transversal areolation extending from base of spiracle to mid of flank, ending near crenulate sulcus; laterally, and dorsal part of metapleuron, broadly polished. Metapleuron ( Fig. 61 ) centrally coarsely areolate­rugose, with long pilosity associated with areolae, plus dense short pilosity in between; ventrally ( Fig. 59 ), including postfoveolar area, pleuropropodeal fovea and extending to interfoveolar area, polished. Hind coxa taken by short transverse elevations, each bearing one long hair on its posterior face, the hairs strongly inclined towards apex; mesally, on ventral half, with dense ventrally decumbent short hairs. Hind femur and compressed half of hind tibia polished, dilated half weakly but distinctly alutaceous; femur and tibia covered with long, sparse, stiff pilosity, inclined about 45 degrees towards apex; hind tibia posteriorly strongly pinched on basal 0.5 ( Figs 55–57 ), generating a posterior carina or edge ( Fig. 55 ) and a central, large, somewhat circular, transverse compression ( Fig. 57 ); basal half ventrally with a sharp edge, ending where the dilated portion begins.

Metasoma: Petiole ( Fig. 62 ) densely transversely strigate, basal 0.1 rugose, apical 0.1 polished. T3 (2 nd metasomal) polished; T4–6 finely alutaceous; T7 from finely alutaceous to finely microreticulate; T9 microreticulate, the individual reticles hexagonal. Pygidial sulcus V­shaped; pygidium large, its apical margin widely polished, isolated from basal portion by a row of long, apically decumbent hairs; area behind hairs somewhat irregular, alutaceous.

Color. Body mostly dark brown with slight reddish tint (040,038,038), head behind eyes, propodeum and basal 0.3 of petiole dark reddish brown (100,040,050). Antennae, except dark brown apex, malar space, fore and mid legs, and hind tibia and tarsus, caramel­colored, with some reddish tint (160,075,015). Wing membrane slightly amber (209,204,168), veins dark brown.

Morphological variation (female). Range of biometric values in Table 1. Gena sometimes (20%) dark brown, rarely (15%) glabrous; occipital carina often (40%) dorso­centrally slightly projected, thus widest at this point (need be observed with steady specimen); post­ocellar carinae sometimes (20%) strongly ondulate, blending with overall vertex sculpture; colo rarely (10%) transverse, 2.1–2.3 times wider than centrally long; mesopleural foveolae in one specimen (5%) mostly spaced at much less than their diameter, and in another specimen spaced at 1.5–3.0 their diameter; the series of transverse areolation on spiracular groove often (40%) distinctly less regular and more degenerate than in the holotype, the areolation giving place to foveolation; interfoveolar area sometimes (30%) mostly or fully weakly crenulate. The female from El Zapotal shows the above described variation for occipital carina, colo, mesopleuron and spiracular groove, and is the only studied specimen with the posterior coronal tubercles converging and fusing mesally; these differences, however, are either too weak, too restrict, or too inconsistent to suggest a separate species.

Comments

Similar to the North American M. arizonicus Townes , with which it shares a nearly identical structure of the hind tibia, but separated from that species by having frons taken by sharp, transverse to sometimes oblique, parallel carinae, some pairs forming channels that extend uninterrupted from one eye margin to the other (vs. carinae forming areolate pattern, therefore with channels crossed one or more times); vertex sculpture not or barely reaching occipital carina, leaving a polished space along occipital carina ( Fig. 51 ) (vs. reaching occipital carina, at least centrally, Figs 26, 30 ); propodeum with small to medium size foveolae, most separated by 0.5­1.0 their own diameter ( Fig. 60 ), often with aligned microfoveolae centro­longitudinally (vs. with corase foveolae, nearly all of them meeting or coalescent with each other, leaving no space for microfoveolae, as in Figs 85, 86 ); and interfoveolar area normally polished ( Fig. 59 ), rarely with 2 or more weak crenulations (vs. entirely and deeply crenulate, Figs 33, 34 ). Immediately isolated from the Cuban and southern Floridian M. brunneus Cresson by having prosternum with small, widely separated foveolae ( Fig. 53 ) (vs. large and nearly meeting) and ovipositor sheath with a pre­apical white stripe (vs. uniformly dark). Somewhat similar to M. peninsularis , but isolated by having gena on ventral half with small and clearly separated punctures ( Fig. 52 ) (vs. large or very large punctures nearly meeting each other, Fig. 80 ), among other features.

MALE. As with females, the males also show extreme body length variation, ranging from about 12–38 mm, with extreme specimens occurring even in a same general collecting area (e.g., in Chamela, Jalisco). In other features also generally similar to female, except as follows. Pronotum visibly more elongate than on female; colo with one or all carinae oblique towards pronotal fold; smallest specimen (OSUC22892) with only two pairs of carinae; hind tibia strongly pinched, but much less strong than on female, not generating a somewhat circular, transverse compression; yet, hind tibia posteriorly, in lateral view, at strongest point of lateral compression, with a protruding, sometimes weakly translucent flange; propodeum sculpture very variable, with foveolation from weak and scattered to coarse and centrally much more densely distributed than laterally; also centro­longitudinally usually with several microfoveolae between major foveolae; petiole nearly entirely polished, except basal end with weak rugosity, but on smallest specimens at least dorsally fully weakly transversely strigate; all other tergites entirely polished. Isolated from males of M. arizonicus by the same diagnostic features listed for females (see above), but also different by having propodeal sculpture normally showing distinct polished spaces between foveoale, except on smallest specimens (vs. fully areolate­rugose in males of M. arizonicus ). The central flange on posterior side of hind tibia is weak in males of M. arizonicus , but similar enough to make this feature of little diagnostic use.

Distribution Throughout Mexico; also in Central America (unpublished data; will be treated elsewhere).

Material examined

Eleven females and 9 males. Holotype ♀ EBCC “ Mexico, Jalisco, Est. de Biología Chamela , 2­VIII­1994, Col. R. L. Westcott. OSUC22889 [barcode, plastic].” Complete, well preserved . Paratypes: ♀ CNCI “ Mexico, Q. Roo: X­can, E. Welling , VIII­1963. OSUC22882 .” ♀ CNCI “ Mexico, Q. Roo: X­can, E. Welling , VIII­1963. OSUC22883 .” ♀ CNCI “ Mexico, Q. Roo: X­can, E. Welling , VIII­1963. OSUC22885 .” ♀ EBCC “ Mexico, Jalisco, Est. de Biología Chamela , 8­VII­95, F.A. Noguera. OSUC22899 .” ♀ EMEC “ Mexico, El Zapotal, 2 mi. S. Tux. Guitierrez, Chias. VII­11­57. J.A. Chemsak, B.J. Rannells, Collectors. OSUC22871 .” ♀ EMEC “ Mexico, Jalisco, Est. Biol. Chamela , VII­ 28 / VIII­2­84, J.T.Doyen. OSUC22886 .” ♀ EMEC “ Mexico, Simojavel , Chiapas, VII/18­ 31/58, J.A. Chemsak. OSUC22887 .” ♀ EMEC Mexico, Jalisco, Est. Biol. Chamela , VII/ 14­22/1992, J. Chemsak. OSUC22890 .” ♀ EMUS Mexico, Jalisco, Chamela , 1­8/X/85, F.D. Parker & T.L. Griswold. OSUC22897 .” ♀ LACM “ Mexico, Veracruz, 9mi. nw. Sontecomapan , 22 July 1970, E. Fisher & P. Sullivan. OSUC22895 .” 2 ♂♂ CNCI “ Mexico, Q. Roo: X­can, E. Welling , VIII­1963. OSUC22881 & OSUC22884 .” ♂ AMNH “ Mexico, Chiapas, Ruins at Palenque , June 26–30, 1959, P. & C. Vaurie. OSUC22900 .” ♂ EBCC “ Mexico, Jalisco, Chamela , fecha 19­VI­91, R. Ayala, s./. OSUC22894 .” ♂ EBCC “ Mexico, Jalisco, Chamela , fecha 1­VIII­85, R. Ayala, s./. OSUC22891 .” ♂ EBCC “ Mexico, Jalisco, Est. Biol. Chamela , 5­VII­93, F.A. Noguera. OSUC22893 .” ♂ EBCC “ Mexico, Jalisco, Estacion de Biologia Chamela , 8­IX­85, M. Sánchez. OSUC22892 .” ♂ EMEC “ Mexico, Jalisco, Est. Biol. Chamela , VII/14­22/1992, J. Chemsak. OSUC22888 .” ♂ UCDC Mexico, 22 mi South Matias Romero , Oaxaca, IV­5­62, F.D. Parker & L.A. Stange. OSUC22896 .”

Figures

FIGURES 9–16. Values of morphometric ratios for all examined female specimens of all species of Mexican Megischus. Species grouped in the Y­axis according to their order of appearance and morphological similarity in the key to species; key structure also indicated by the dendrogram applied to Y­axis of Figure 9. Legends for all graphs: an, M. anaxeus, sp. n.; az, M. arizonicus; bc, M. bicolor; cl, M. celaenocephalus, sp. n.; jc, M. jaliscoensis, sp. n.; ml, M. melanogladius, sp. n.; mx, M. mexicanus, sp. n.; ng, M. niger; pn, M. peninsularis, sp. n.; tx, M. texanus. For ratio abbreviations, see text.

FIGURES 51–59. Megischus anaxeus, sp. n., ♀. 51, head, dorsal, holotype; 52, head, lateral but slightly more posterior than anterior, to show gena, holotype; 53, prosternum, ventral, slightly shifted towards left hemisternite, holotype; 54, pronotum and anterior part of mesonotum, dorsal, paratype; 55, hind left tibia, posterior view, paratype; 56, hind left tibia, lateral, paratype; 57, same, detail of central compression; 58, propodeum + dorsal part of metapleuron, to show spiracular groove, left, holotype; 59, interfoveolar and postfoveolar areas, between mesopleuron and metapleuron, holotype. Illustrations not to scale.

FIGURES 60–62. Megischus anaxeus, sp. n., holotype ♀. 60, propodeum + metapleuron, dorsal;

FIGURES 26–34. Megischus arizonicus Townes, ♀. 26, head, dorsal; 27, head, dorso­lateral; 28, gena, left; 29, pronotum and anterior part of mesonotum, dorsal; 30, pronotum, anterior half, dorsal; 31, axilla, scutellum and crenulate sulcus, dorsal; 32, mid left coxa; 33, mesopleuron, propodeum (part) and metapleuron (part), left; 34, interfoveolar area, propodeum and metapleuron, left. Illustrations not to scale.

FIGURES 79–86. Megischus peninsularis, sp. n., holotype ♀. 79, head, dorsal; 80, head, dorsolateral, left; 81, head, latero­ventral, slightly shifted posteriorly to show gena; 82, posterior half of pronotum, mesopleuron, and part of propodeum + metapleuron, left; 83, axilla, scutellum and crenulate sulcus, shifted to the left; 84, post­foveolar area and mid coxa, left; 85, propodeum + metapleuron, dorsal; 86, same, detail of left side. Illustrations not to scale.