Xeranthrena Gonzalez and Engel, 2017

Gonzalez, Victor H., Smith-Pardo, Allan H. & Engel, Michael S., 2017, Phylogenetic Relationships Of A New Genus Of Calliopsine Bees From Peru, With A Review Of Spinoliella Ashmead (Hymenoptera: Andrenidae), Bulletin of the American Museum of Natural History 2017 (412), pp. 1-72 : 14-18

Xeranthrena Gonzalez and Engel , new genus

TYPE SPECIES: Xeranthrena imponticula Gonzalez and Engel , new species.

DIAGNOSIS: The new genus is most similar to Spinoliella but can be easily separated by the following combination of characters: female clypeus with low projection on distal margin near lateral margin of labrum (fig. 2B, C), preapically depressed on disc, with elevated apical ridge medially (with strong projection, convex on disc, and without distinct ridge in Spinoliella ); female S6 with proximal lobes about as long as apodemes (fig. 2I) (surpassing apodemes in Spinoliella ); male S8 with body rectangular, abruptly separated from apically expanded median process (fig. 3G) (body triangular, gradually separated from median process, not apically expanded in Spinoliella ); penis valve apically simple, asetose, not fused dorsally by bridge (fig. 3H, I) (apically bifid, setose, fused medially by bridge in Spinoliella ); and male metatibia with keirotrichia occupying entire inner surface (absent anteriorly in Spinoliella ).

DESCRIPTION: Female. Moderate-sized bees (7–10 mm in length); color dark brown to black, with yellow maculation on mandible, face, pronotum, and metasomal terga (fig. 2A–D, H); integument largely smooth and shiny between punctures, especially on dorsal surface of mesosoma; punctures finer on metasoma; pubescence whitish, sparse, longer and denser on head and mesosoma than on metasoma; metasomal terga and sterna covered by minute, appressed setae. Head broader than long, broader than meso- soma; mandible edentate, pointed, with strong basal process on upper margin; labrum with weak ridge bordering glabrous, impunctate, basal area; clypeus more than 3× broader than long, distal margin with low projection near lateral margin of labrum; labrum broader than long, asetose basal area delimited by weak border, apex not inflexed; lower mesal paraocular area distinctly swollen (fig. 2B); anterior tentorial pit at midpoint of outer subantennal sulcus; lower margins of antennal toruli at lower one-third of face; facial fovea well-marked, narrow; inner orbits of compound eyes parallel (fig. 2A); lower margin of median ocellus below upper orbital tangent; vertex convex; gena slightly narrower than compound eye in profile, widest medially. Labiomaxillary complex of moderate length, not distinctly elongate; maxillary palpus with six palpomeres, apical three palpomeres each shorter than basal three individually; labial palpus with four palpomeres, first palpomere much longer than combined lengths of remaining palpomeres, second palpomere slightly longer than third and fourth palpomeres individually; glossa slightly shorter than prementum.

Pronotal collar rounded, not carinate; dorsal surface of propodeum microareolate, asetose, gently sloping, 1.6× longer than metanotum. Forewing with pterostigma more than 3× longer than broad, about as wide as prestigma, margin basal to r-rs slightly divergent from C, that within marginal slightly convex; marginal cell obliquely and broadly truncate at apex, appendiculate, longer than distance from its apex to wing tip; two submarginal cells, first submarginal cell slightly longer than second; basal vein (1Rs+M) gently curved; 1m-cu distal to 2Rs (i.e., second free abscissa Rs, or “first submarginal crossvein” sensu Michener, 2007); 2m-cu basal to 2rs-m (“second submarginal crossvein” sensu Michener, 2007); jugal lobe 0.9× length of vannal lobe. Hind wing with second abscissa of M+Cu about 3.8× length of cu-a; 10–12 distal hamuli. Legs unmodified; mesotibial spur ciliate, straight, about one-half mesobasitarsal length; metabasitibial plate spatulate, slightly concave on disc, delimited by strong border (fig. 2F), with scattered, semierect, short, stiff setae basally; metatibia 1.7× longer than metabasitarsus, with keirotrichia on inner surface present only at both ends, scopa on outer surface with extremely sparse, mostly unbranched setae except minutely branched on posterior margin basally; metatibial spurs ciliate, straight, inner spur about 1.3× longer than outer spur; metabasitarsus not projecting on posterodistal margin; pretarsal claws cleft, with outer ramus longer than inner.

Metasoma broader than mesosoma; terga without apical bands of setae (fig. 2G); T2 with well-marked lateral fovea; T7 with pygidial plate apically simple, pointed; S6 with proximal laminar lobes not surpassing anterior margin of apodemes, reflexed layer (“duplication” sensu Ruz, 1991) strongly sclerotized, broadly convex, subapically with dense, continuous band of setae, distal margin concave medially (fig. 2I); sting apparatus developed, with stylet apically acute, not surpassing gonostylus.

Male. Antennal scape unmodified, nearly reaching lower margin of median ocellus (fig. 3A); flagellum shorter than head; inner orbits of compound eyes weakly to strongly divergent ventrally (fig. 3A). Outer surfaces of pro- and mesotibiae apically with small, posterior spine; keirotrichia occupying entire inner surface of metatibia. Metasoma straight, with apex posteriorly directed; sterna unmodified; S5 with distal margin straight; S6 medially projected on distal margin; S7 with apodemes forming a broad, inverted V, apically with two large lobes (fig. 3F); S8 with body rectangular, abruptly separated from apically expanded median process (fig. 3G); gonocoxite square or nearly so, ventrally completely fused on midline, with strong dorsomedial projection distally; gonostylus vestigial, about one-eighth of gonocoxite length in ventral view (fig. 3H); volsella indistinct, presumably represented by sclerotized, digitiform area fused to gonocoxite and gonostylus, as seen in ventral view (fig. 3H); penis valve free, not fused medially by narrow bridge (fig. 3H), apically simple, asetose, weakly sclerotized, laterally compressed (fig. 3H, I); penis fused to penis valve, partially sclerotized.

ETYMOLOGY: The new genus-group name is a combination of xeros (Greek, “dry,” referring to the xeric regions inhabited by these bees), and anthrene (Greek, “wild bee”). The gender of the name is feminine.