Megachile (Litomegachile) pankus Bzdyk, 2012

Sheffield, Cory S. & Genaro, Julio A., 2013, A new species of Megachile (Litomegachile) from Cuba, the Antilles (Hymenoptera: Megachilidae), Journal of Melittology 2013 (19), pp. 1-17 : 10-13

Megachile (Litomegachile) pankus Bzdyk, 2012

( Figs. 6–8 )

DIAGNOSIS: The female of M. pankus can be recognized by the combination of the mandible with angulation between the 3 rd and 4 th (inner) teeth, scopa of only S6 partially black, and T6 concave in profile, with erect hairs arising above the appressed black pubescence. It is most similar to M. gentilis Cresson , M. snowi Mitchell , and M. mendica , which share the mandibular structure. Females of M. gentilis have the scopal hairs of S6, and apically on S5 entirely black; females of M. snowi and M. mendica have T6 straight in profile and without erect hairs. The male of M. pankus is distinct in having the mandibular condyle very pronounced ( Fig. 6 ), and can be recognized by the combination of T5 lacking apical fascia ( Fig. 7c ) and T2 thinly but completely fasciate. It is most similar to M. gentilis , M. snowi , and M. mendica . Males of M. gentilis and M. snowi have T5 fasciate apically; M. mendica have T2 with apical fascia restricted to the lateral edges.

DESCRIPTION: ♂: Length: 9.0 mm. Forewing length: 7.5 mm. Head width 3.5 mm; head length 2.5 mm ( Fig. 7b ). Intertegular distance 2.6 mm; distance between outer margins of tegulae 3.2 mm.

Color. Integument black, except for flagellum brown beneath, tegula and apical tarsomere dark brown, tibial spurs dark yellowish-brown, front femur reddish yellow below, apical edge of S2–S5 hyaline (1 MOD); wings subhyaline, with outer half including within marginal cell somewhat darkened along apical edge, veins dark brown to black.

Structure. Compound eyes convergent below ( Fig. 7b ); lateral ocelli as near to edge of vertex as to compound eye; mandible 3-dentate, lower process of mandible slender, acute, submedian in position with a pronounced condyle ( Fig. 6 ); clypeal margin shiny and impunctate, broadly and shallowly emarginated medially; gena slightly narrower than compound eye (3.5:3). F1 about as long as broad, subequal in length to pedicel, and half as long as F2, F2 longer than broad (2:1), F3–F10 longer than broad (2:1.3), apical flagellomere more elongate, almost twice as long as broad. Front coxal spine short, distinct, quadrate to slightly longer than broad, subacute. T2 and T3 rather deeply grooved across base, grooves on T4 and T5 more shallow but distinct, basal depressions carinate; apical margins of T2–T5 depressed laterally, less so medially; T6 vertical in position, the carina quite conspicuous, with a rather deep, semicircular median emargination, finely and irregularly denticulate on each side in apical half, median carinate teeth of apical margin of segment rounded to subtruncate, further apart from each other than distance to small lateral acute teeth; T7 hardly visible, apical margin rounded to subtruncate, with a small median triangular protuberance. S5 with pregradular area wide medially, about 1/3 medial length of plate, postgradular area subtriangular, narrowest basally and widest apically, with apical rim produced ( Fig. 8c ); S6 with apical lobe produced medially, with lateral edges angulate, postgradular setal patch widely divided medially ( Fig. 8b ); S8 with lateral edges converging in basal half, subparallel in apical half, evenly rounded apically ( Fig. 8a ). Genitalia with gonocoxite not protuberant at base, slightly narrowed above base; gonostylus unmodified ( Figs. 8c, 8d ).

Surface sculpture. Punctures fine and close on face, rather shallow on gena, deeper and rather fine and close on vertex medially, more irregular sized but still close on vertex laterally, quite coarse but close on clypeus, becoming finer and closer in apical half, fine and close on supraclypeal area, apical edge of clypeus shiny and impunctate. Mesoscutum with punctures deep, rather fine and uniformly close, finer and close over most of mesoscutellum and pleura; tegula finely and closely punctate throughout; propodeum with shallow, fine punctures with i=1–2pd; triangle dull, smooth and impunctate. Metasoma with punctures fine, minute and very close on T2, larger but still close (i<1pd) on T3, larger and more sparse (i=1–2pd) on T4, elongate on T5 with shiny i≤1pd, fine and densely crowded on T6; S1 with punctures coarse and close (i<1pd), becoming more sparse (i=1–2pd) on S2 and S3, S4 with surface shiny with very sparse (i=3–4pd), coarse punctures.

Pubescence. Mostly white on body; dense and entirely white on face below level of median ocellus, short, sparse and entirely dark on vertex area; mesoscutum sparsely pale pubescent but faintly intermixed with shorty, erect dark hairs, especially in posterior half, becoming long, dense and entirely white at periphery, a few subappressed hairs at mesoscutal-mesoscutellar suture; terga mostly white pubescent, including basal tomentum on T2–T5, T3 and T4 with dark, erect hairs basal to white apical fasciae, fasciae complete on T1–T4, though thin medially, entirely lacking on T5 ( Fig. 7c ), T6 with abundant pale tomentum hiding most of surface.

DISTRIBUTION: As discussed by Bzdyk (2012), M. pankus was known only from Mexico (Hidalgo, Pachuca; Sonora, Alamos ; Sinaloa, Mazatlan ; Sinaloa, 4 mi NW Choix; Sinaloa, 6 mi NW Choix). This is supported here; labels from one of the male specimens described here reads: MEXICO: Sonora, 30 km E Agua Prieta, 31°19’32”N 109°16’00”W, 7 Aug 2007, R . L. Minckley , ex. Lepidium thurberi, Pol 27 horse corral, AM SBV076514 ; DNA barcode accession #s: 04744G10- MEX, BBOFWM652-10 . Additional specimens examined (with partial DNA barcodes) include: 1♀, USA: Arizona, Cochise Co., San Bernardino NWR, 31°20’16”N 109°15’44”W, 5 May 2001, A. Romero, ex. yellow bowl, R6 T4 , 011814 ; DNA barcode accession #s: 04744G06- AZ, BBOFWM648-10 ; 1♂, USA: New Mexico, Hidalgo Co., Hwy 80, 32.094, -108.968, 1367m, 15.viii.2007, J. Gibbs and C. Sheffield // Megachile mendica snowi Det. C. Sheffield ; DNA barcode accession #s: 07-NM-2100, BEECC427-08 .

COMMENTS: Megachile pankus belongs to the mendica group, as supported by morphological and COI analysis. It is most similar to M. mendica , with 2.52% sequence divergence between the two species.

Figures

Figure 6. Lateral view of mandible of Megachile (Litomegachile) pankus Bzdyk, male. Lower process of mandible is submedian in position, and red arrow shows pronounced condyle, both characters diagnostic for males of this species.

Figure 7. Megachile (Litomegachile) pankus Bzdyk, male. a. Lateral. b. Face. c. Dorsal view of apical terga, showing absence of an apical fascia on tergum 5 (T5).

Figure 8. Hidden sterna and genitalia of Megachile (Litomegachile) pankus Bzdyk, male. a. Ster- num 8 (S8). b. Sternum 6 (S6). c. Sternum 5 (S5). d. Genitalia, dorsal. e. Genitalia, ventral.