Rhynostelis xavieri Mahlmann, 2020

Mahlmann, Thiago, 2020, A new species of the previously monotypic Neotropical cleptoparasitic bee genus Rhynostelis, with notes on Rhynostelis multiplicata (Hymenoptera: Megachilidae), Journal of Melittology 2020 (96), pp. 1-8 : 2-4

Rhynostelis xavieri Mahlmann , new species

ZooBank: urn:lsid:zoobank.org:act:FDA24339-0C58-4870-B4A8-CF0A65AA871E

( Figs. 1–4 )

DIAGNOSIS: Females of this species can most readily be separated from those of R. multiplicata (Smith) as follows: in R. xavieri the process at the base of each mandible is bigger and slightly bent, the median basal projection of the clypeus is much larger and flat ( Fig. 1 ), and the labrum is entirely yellow with a larger tubercle, which is not bilobed near the clypeal base ( Figs. 1, 2 ). Additionally, the protuberances on the mesoscutum are larger, more acute, hairless, and whitish apically ( Fig. 3 ); the omaular carina is very pronounced, lamellate, and extends ventrally near the forecoxa.

DESCRIPTION: ♀: Body length approximately 13 mm; forewing length 10.3 mm; head width 4.3 mm; head length 3.1 mm; compound eye length 2.6 mm; ocelloccipital distance about 2 OD; ocellocular distance about 2.3 OD.

Structure. Mandible with five teeth, apical tooth elongate; basal area with strong, slightly bent, tooth-shaped process ( Fig. 1 ). Labrum with large basal tubercle. Clypeus flat with a median, large, and flat basal projection. Frons with long, well-marked carina. Juxtantennal carina short, lamellate, and extending upward. Mesoscutum and mesoscutellum bigibbous; protuberances on mesoscutum large, pointed, and hairless, apex of each higher than adjacent hairs; axilla gibbous; metapostnotum with weak row of pits connecting postspiracular foveae; propodeum with irregular fovea delimited posteriorly by carina behind spiracle. Omaular carina quite pronounced, lamellate, extending ventrally near forecoxa; mesepisternum notably convex in lower half. Fore and middle tibiae with dorsoapical spine on outer surface; arolia present. T6 deeply concave. S1 with pronounced keel.

Coloration. Head integument yellow except as follows: mandible black apically; large black quadrangular area arising above superior margin of antennal sockets extending to vertex and above compound eyes. F3 to F10 with ventral surfaces darkish yellow. Pronotal lobe yellow; mesoscutum black with reverse U-shaped yellow macula on each side; mesoscutellum black with yellow gibbous area on each side; axilla yellow; metanotum black; metapostnotum and propodeum yellow, propodeum basally with triangular black spot. Mesoscutum with pair of protuberances hairless and whitish at apex. Mesepisternum yellow except for discal black spot and black scrobe; metepisternum yellow with V-shaped black macula. Tegula amber and wing membrane brown. Legs almost totally yellow; all coxae with dorsal black spots, middle femur with external darkish area; middle and hind tibiae with internal and external darkish areas. Metasomal terga black except T1 yellow basally and with yellow continuous discal band slightly angled anteromedially; T2 to T6 each with large yellow band interrupted at midline. Sterna almost entirely yellow except S1 to S5 with narrow black area basally and translucent distal margin; S5 with lateral black spots; S6 black with lateral yellow spots.

Pubescence. Golden yellow, ventrally lighter, with moderate size hairs (about 1 OD). Frons among ocelli and mesoscutellum with longer and denser hairs. Mesepisternum with hairs longer than hairs on mesoscutum. Mesoscutum almost glabrous on convex areas. S1 to S4 sparsely hairy, hairs denser on S5 and S6.

Sculpture. Head finely punctate with sparser punctures on clypeal disc. Labrum and mandible impunctate, integument weakly rugose. Mesoscutum with integument microreticulated, punctures deeper than those on head, protuberances finely punctate. Mesepisternum with larger and sparser punctures on convex areas than elsewhere; distance between punctures at least one puncture diameter. Punctures of terga fine; yellow bands with punctures larger and sparser than those on black areas. T4 and T5 with median longitudinal weak impunctate carina.

♂: Unknown.

HOLOTYPE: ♀, Brazil: Amazonas, Benjamin Constant , 4°25’3.96”S; 70°3’37.73”W, rede entomológica, varredura, x.2019 [October 2019]; F. Xavier Leg. ( INPA).

GEOGRAPHIC RECORD: Brazil (Amazonas).

ETYMOLOGY: The specific epithet honors the Amazonian entomologist Francisco Felipe Xavier Filho, who collected and provided the material for this study.

Figures

Figures 1–4. Holotype (female) of Rhynostelis xavieri, new species. 1. Head, dorsolateral view. 2. Head, frontal view (figures 1–2: scale bar = 1 mm). 3. Dorsal habitus. 4. Lateral habitus (figures 3–4: scale bar = 5 mm).