Mexalictus (Mexalictus) vitriolus 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 : 55-57

Mexalictus (Mexalictus) vitriolus Dumesh , new species

( Figs. 158–161 )

Holotype. Male. MEXICO, Jalisco, Las Manzanilla , 23 Octobre 1990, C.M. Estrada #63 [ CUIC].

Diagnosis. This species can be distinguished by the following combination: face, mesosoma, and metasoma extremely finely and sparsely punctate and surface shiny, relative to all other species in the genus. Mesoscutellum basally medially depressed; metapostnotum imbricate with very short basal striation, covering less than basal 1/5 of dorsal surface. The male mandible lacks a subapical tooth. This species is most similar to M. arizonensis , but can be differentiated by the shiny and sparsely punctate surface of the entire body (punctures distinct and denser).

Description. Male (Holotype): Body length 5.7mm, wing length 4.5mm, head width 1.55mm, ITW 1.05– 1.10mm. Head brown with metallic green reflections, mesosoma pale brown with greenish metallic reflections. Head: round to slightly wider than long, L:W = 0.97:1. (1) Labrum and mandible: labrum with subrectangular basal area, medial length 0.33X width, basal elevation flattened, apicomedian area elevated, distal process narrow triangular; mandible dark brown basally, becoming red apically. (2) Clypeus: shiny, with metallic green reflection except for apex; length slightly shorter than supraclypeal area (~0.9X), 0.5 of length below lower ocular tangent, weakly convex in lateral view, slightly less protuberant than supraclypeal area; punctures fine and sparse, separated by 2–3pd, somewhat larger on apical half. (3) Supraclypeal area: shiny, slightly dulled mesad of antennal sockets; convex, protuberant, about 0.68–0.70X as wide as long; punctures few, separated by 2pd, nearly absent apicomedially. (4) Lower paraocular area: shiny, becoming weakly dull towards antennal socket; punctures separated by 1–2pd, punctures fine and well separated towards paraocular lobe. (5) Frontal area: frontal line carinate between antennae, about halfway to median ocellus; compound eye more convex below than above; punctation crowded above antennae (<1pd). (6) Vertexal area: shiny, with weak transverse depression; IOD = 1.4MOD, OOD = 1.3MOD, OVD = 1.0MOD; punctures separated by 1–2pd. (7) Genal and hypostomal areas: genal area narrower than compound eye in lateral view, shiny with fine punctures separated by>2pd, hypostomal area shiny with extremely sparse punctures, separated by>4pd. (8) Antenna: orange-brown, scape, pedicel, and F1–F3 darker than F4–F10; scape reaching posterior margin of median ocellus; pedicel slightly longer than wide, subequal in length to F1; F1 wider than long, F2 to F10 as long as wide or longer than wide, increasing in length apically. Mesosoma: (9) Pronotum: smooth, nearly impunctate, polished; posterodorsal margin of pronotum with complete band of hairs, including pronotal lobe which is densely outlined. (10) Mesoscutum: entirely shiny and polished; punctures of 2 sizes, larger punctures separated by>6pd, smaller punctures separated by 2–4pd, punctures sparser medially and posteriorly. (11) Mesoscutellum: shiny and convex, punctures fine and similar to the large punctures of mesoscutum, separated by ~5pd, apical margin with dense punctures. (12) Metanotum: shiny to slightly dull; punctures denser than those of mesoscutum and mesoscutellum, separated by ~2–3pd. (13) Mesopleuron: shiny, sparsely and very finely punctate, punctures separated by 3–4pd; pre-episternum shiny, punctation as for mesopleuron; hypoepimeral area and disc of episternum smooth, shiny and nearly impunctate, with a few scattered punctures above (~3pd). (14) Metapleuron: shiny, with minute and weak basal transverse striation. (15) Metapostnotum and propodeum: length of metapostnotum subequal to posterior width; posterior margin rounded, dorsally bare, basal striation very short, covering less than basal 1/5 of surface; propodeum somewhat shiny, but imbricate and impunctate. (16) Wings: clear, veins orange-brown, stigma about 2/3 as long as marginal cell, membrane slightly infuscate; 1 st recurrent vein meeting 2 nd submarginal cell more than 4 vein widths basad of 2 nd transcubital vein. (17) Tegula: hyaline, punctate anteriorly and along inner margin, with few long branched hairs laterad. (18) Foreleg: hairs whitish yellow; shorter branched erect hairs on tarsus, coxa, trochanter, and femur; dense long unbranched hairs on tibia and basitarsus. (19) Middle leg: as foreleg except as follows: femur slightly ventrally concave apically; tibia with lateral patch of pale, long dense pubescence on apical 2/3. (20) Hind leg: as middle leg except as follows: tibia with pubescence longer; basitarsus laterally flattened, especially outer surface; femur>3X as long as greatest width; tibia 5X as long as greatest width; basitarsus 4.5X as long as greatest width; tibial spurs translucent yellow, apically darkened; inner hind tibial spur short, microserrate, with over 15 short, close teeth. Metasoma: Metallic reflections absent (21) Terga: shiny and polished, brown basally becoming translucent on apical impressed areas (1–1.2MOD); punctures separated by>3pd, apical impressed areas impunctate; pubescence pale, longer laterally. (22) S5 slightly concave centrally, medial plumose hairs longest apically, projecting ventrally as apical tuft; S6 slightly elevated apically with an apical patch of plumose medially directed hairs. (23) Terminalia: see Figs. 160, 161 .

Female: unknown

Material examined. MEXICO, Jalisco, Las Manzanilla , 23 Octobre 1990, C.M. Estrada #63 (holotype male [ CUIC]) .

Etymology. This species is named for its shiny, glass-like appearance. It is the only species of this genus with such sparse punctation and shiny surface sculpture.

Comments. The locality is La Manzanilla, but reads “Las Manzanilla on the original label.

Subgenus Mexalictus (Georgealictus)

Type species. M. polybioides Packer, 1993 . Can. J. Zool. 71: 1656–1659. By original designation.

Diagnosis. Species of this subgenus can be distinguished by their larger size, wasp-like appearance, and weak to absent metallic reflections in comparison to species of the nominotypical subgenus; head about as long as wide (slightly longer than wide in most), body dull and granular in appearance (shiny to weakly dull); metasoma petiolate with T1 longer than wide (T1 normal), T1 transparent with a yellow apical band (terga uniform); wings with marginal cell infuscate, darker than rest of wing (wing not infuscate).

Figures

FIGURES 158–161. Mexalictus vitriolus Dumesh, n. sp., 158. Male lateral habitus, 159. Male head, 160. Male genital capsule, dorsal view, 161. Male genital capsule, ventral view. Scale bars = 1mm.