Mexalictus (Mexalictus) astriatus Dumesh, 2013

DUMESH, SHEILA, 2013, <p> <strong> Revision of the rare Mesoamerican bee genus <em> Mexalictus </ em> (Hymenoptera: Halictidae) with the description of </ strong> <br /> <strong> 21 new species </ strong> </ p>, Zootaxa 3708 (1), pp. 1-80 : 22-24

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Mexalictus (Mexalictus) astriatus Dumesh

new species

Mexalictus (Mexalictus) astriatus Dumesh , new species

( Figs. 94–99)

Holotype. Female. MEXICO, Mexico, 16 mi. E Toluca, 9500’, 31 July 1962, University of Kansas Mexico Expedition [ KUM].

Diagnosis. Both sexes of this species can be distinguished by their metapostnotal sculpture which lacks striae, all other species have striae at least basally on the metapostnotum. In addition, the following combination: supraclypeal area impunctate on disc; apical dark region of clypeus triangular; first recurrent vein entering second submarginal cell 1/3 cell length from apex. This species is most similar to M. micheneri with which it shares the elongate head, but can be differentiated by the non-striate dorsal metapostnotum. It is slightly larger in size than most other members of this subgenus.

Description. Female (Holotype): Body length 8.8mm, forewing length 6.0– 6.3mm, head width 1.72– 1.75mm, ITW 1.28–1.33mm. Head and mesosoma metallic greenish blue, pubescence pale whitish. Head: slightly longer than wide, L:W = 1.15–1.18:1. (1) Labrum and mandible: labrum dark brown with subrectangular basal area, medial length equal to half of width, basal elevation flattened, apicomedial area elevated, distal process narrow triangular; mandible basally dark brown becoming apically red, with distinct subapical tooth. (2) Clypeus: shiny, nearly half apical surface dark purple-brown; length subequal to length of supraclypeal area, 0.8 of length below lower ocular tangent, weakly convex in lateral view, slightly protuberant; punctures of 2 sizes basally, smaller punctures separated by <1pd, larger punctures separated by <2pd; punctures coarser and sparser apically, separated by>2pd; with subapical row of dark bristles. (3) Supraclypeal area shiny, convex, more protuberant than clypeus; length subequal to clypeal length; greatest width subequal to length from upper clypeal margin to lower margin of antennal sockets; punctation absent apicomedially (apical 2/3 impunctate medially), lateral areas with punctures separated by 1–2pd; punctures smaller and more dense and surface slightly dull below antennal sockets. (4) Lower paraocular area: shiny, becoming dull towards antennal socket; punctures separated by <1pd, becoming slightly sparser lateral to supraclypeal area, punctures fine and well separated towards paraocular lobe; paraocular lobe black and nearly impunctate. (5) Frontal area: frontal line carinate between antennae from lower margin of antennal socket to 2ASD above antennal socket, line absent above; shiny impunctate triangle anterior to medial ocellus; punctation dense and crowded above antennae, separated by 1–2pd, very small and fine around inner margin of compound eye. (6) Vertexal area: shiny, with weak transverse depression; IOD = 1.7MOD, OOD = 1.85MOD, OVD = 1.0MOD; larger punctures separated by 2pd, smaller punctures closely spaced, <1pd, becoming obscure posteriorly. (7) Genal and hypostomal areas: genal area as wide as compound eye in lateral view, shiny with fine punctures separated by 1–2pd, hypostomal area nearly impunctate, slightly dull posteriorly. (8) Antenna: dark brown, flagellum weakly reddish ventrally, scape, pedicel, and F1–F3 darker than F4–F10; scape reaching posterior tangent of median ocellus, subequal in length to F1–F5 (half flagellar length); pedicel slightly longer than wide, F2 and F3 subequal in size, both wider than long and shorter than F1; flagellomeres slightly increasing in length from F4–F10, F10 longer than wide. Mesosoma: (9) Pronotum: shiny and impunctate, slightly dull ventrolaterally; posterodorsal margin of pronotum with complete band of hairs, including pronotal lobe which is densely outlined. (10) Mesoscutum: slightly dull; punctures of 2 sizes: larger punctures deep, separated by 2–4pd, smaller punctures shallow and more dense, separated by 1–2pd. (11) Mesocutellum: slightly impressed medially; large punctures similar to those of mesoscutum, small punctures much finer than those on mesoscutum, separated by 1pd except separated by 2pd around median line. (12) Metanotum: punctures similar to those of mesoscutellum, surface very dull; short whitish yellow hairs forming a posterior band. (13) Mesopleuron: shiny and closely punctate, punctures shallow and somewhat obscure especially ventrally, separated by <2pd; pre-episternum densely and coarsely punctate, weakly granular anteriorly; hypoepimeral area and disc of episternum nearly impunctate and smooth. (14) Metapleuron: transversely striate basally, somewhat shiny and entirely impunctate. (15) Metapostnotum and propodeum: metapostnotum half as long as anterior width; posterior margin truncate, dorsally bare, basally shiny becoming weakly granular medially; propodeum posteriorly somewhat shiny, smooth and impunctate; dorsal striation absent. (16) Wings: clear, veins and stigma brown, stigma slightly more than 1/2 as long as marginal cell, membrane slightly infuscate; first recurrent vein entering second submarginal cell at 1/3 width of cell from apex. (17) Tegula: punctate anteriorly, with few long branched hairs distally, transparent posteriorly, with hyaline, dull anterior margin. (18) Foreleg: hairs pale golden on tarsi, metafemoral brush and anterior surface of tibia; coxa, trochanter, and femur with branching erect hairs; pubescence on tibia and basitarsus dense, hairs long, not branched. (19) Middle leg: as foreleg except, hairs brownish on outer surfaces of tibia and basitarsus and basitibial plate; tibia with dorsal patch of pale, long, dense pubescence on apical 2/3. (20) Hind leg: as middle leg except, coxa and trochanter with long, branching, pale pubescence; femoral scopa well formed basally with branching, long white hairs; tibia densely pubescent, hairs long and erect; basitarsus with several branched hairs, pubescence less dense than on tibia; femur 3X as long as greatest width; tibia 4X as long as greatest width; basitarsus 3.5X as long as greatest width; tibial spurs translucent yellow, apically darkened; inner hind tibial spur curved, with less than 10 longer teeth; outer hind tibial spur sharply angled at apical 1/5, almost at right angle. Metasoma: (21) Terga: shiny, dark brown to black basally becoming lighter brown toward slightly depressed apical area with margin somewhat hyaline; finely and shallowly punctate basally, punctures separated by 2–3pd, nearly impunctate apically; T1 entirely shiny and polished, sometimes with transverse medial dull area; T2–T5 apically shiny and polished, basally slightly dull and rough in appearance due to fine dense punctures; pubescence pale on T1–T4; darker on T5, reddish to dark brown on apical impressed area and pseudopygidial area; T1 with branching pubescence laterally and anteriorly, T2–T4 with pale whitish pubescence laterally, nearly bare medially, T5 with dense pubescence, branched hairs longer than unbranched hairs. (22) Sterna: pubescence long basally on S1; S2– S6 with hairs long, plumose and pale, brownish basally on S5–S6.

Male (Allotype): Body length 8.0mm, wing length 5.4mm, head width 1.56–1.60mm, ITW 1.05mm. As for female except as follows: Head and mesosoma dark green. Apical margin of clypeus dark brown. Head: longer than wide, L:W = 1.14–1.16. (1) Labrum and mandible: labrum basally flattened, sometimes slightly indented, distal process extending beyond basal area for up to 0.5X length of labrum. (2) Clypeus: subapical row of dark bristles absent; mandible with distinct subapical tooth. (4): Lower paraocular area: shiny, slightly dull near lower margin of antennal socket; punctures separated by 1–2pd, small and fine towards paraocular lobe; paraocular lobe very sparsely and finely punctate. (6) Vertexal area: IOD = 1.8MOD, OOD = 1.8MOD, OVD = 1.2MOD. (7) Genal and hypostomal areas: genal area slightly narrower than compound eye in lateral view. (8) Antenna: reaching anterior margin of mesoscutellum; scape reaching anterior tangent of median ocellus; pedicel about as long as wide; F1 slightly longer than pedicel, about as long as wide, longer than F2, subequal in length to F3–F10. Mesosoma: (10) Mesoscutum: shiny; punctures of 2 sizes, larger punctures deep, separated by>4pd, smaller punctures shallow and denser, separated by>2pd. (11) Mesocutellum: slightly impressed medially; punctures similar to those of mesoscutum. (12) Metanotum: punctures slightly denser than those of mesoscutellum; surface shiny. (15) Metapostnotum and propodeum: metapostnotum sometimes with weak basolateral striation. Metasoma (21) Terga: metallic reflections absent; pygidial plate broadly rounded with elevated rim, depressed medially, shiny and smooth, or with irregularly rough areas. (22) Sterna: S4 with long plumose hairs medially directed on concave apico-median area; S5 broadly concave medially, apical plumose hairs longest medially, projecting ventrally as apical tuft; S6 entire, bare basomedially, with plumose hairs medially directed. (23) Terminalia: see Figs. 98, 99.

Material examined. MEXICO, Mexico, 16 mi. E Toluca, 9500’, 31 July 1962, University of Kansas Mexico Expedition (holotype female [ KUM]) ; Mexico, 20 mi. E Toluca, 8900’, 31 July 1954, University of Kansas Mexico Expedition (allotype male [ KUM]) ; Mexico, 15.5 mi. E Toluca, 9500’, 6 July 1961, University of Kansas Mexico Expedition (paratype female [ KUM]) .

Etymology. This species is named for the absence of striation on the dorsal surface of the metapostnotum; all other Mexalictus species possess some degree of striation on the metapostnotum.


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