Chiasmognathus saheliensis, Engel, 2010

Engel, Michael S., 2010, A new species of the bee genus Chiasmognathus from southwestern Niger (Hymenoptera: Apidae), Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 273-278 : 274-277

Chiasmognathus saheliensis sp. nov.

( Figs. 1–5 )

Type material. HOLOTYPE: J, NIGER [Republique du Niger], 20 km S. Tahoua [14°45′N 5°20′E], 13.8.1987 [13 August 1987], A. Pauly col.; specimen deposited in the Department of Entomology, Royal Belgian Institute of Natural Sciences , Brussels, Belgium ( RBINS).

Diagnosis. The new species can be distinguished by the dark reddish brown integument of the head and mesosoma ( Figs. 1–2 ); brown metasoma; sparsely punctured mesoscutum, with punctures gradually becoming more dense posteriorly; strongly punctured pleura, with punctures sparse around the episternal scrobe; and the structure of the terminalia ( Figs. 3–5 ).

Description. Male. Total body length ca. 2.4 mm (estimated by combining lengths of head and mesosoma with that of preserved portions of metasoma which was partial, detached, and previously dissected); forewing length 1.8 mm. Head wider than long (width 0.77 mm, length 0.63 mm); inner margins of compound eyes straight, convergent below; apex of clypeus at lower tangent of compound eyes; ocelli well above upper tangent of compound eyes; clypeus nearly flat; malar space vestigial; mandibles simple, crossing in repose but not covering labrum. Intertegular distance (as measured from between inner margins of tegulae) 0.50 mm. Forewing marginal cell broadly truncate; both m-cu crossveins entering second submarginal cell; hind wing with five hamuli. Male terminalia depicted in figures 3–5.

Clypeus and supraclypeal area with small, shallow punctures separated by a puncture width; face with small, well-defined punctures separated by 1–2 times a puncture width, integument between punctures smooth; punctures becoming slightly more dense on vertex, separated by 0.5–1.5 times a puncture width, integument between punctures smooth; punctures on gena separated by 1–2 times a puncture width, integument between punctures smooth; frontal line carinate from lower tangent of toruli to about 0.75 times median ocellar diameter from median ocellus, becoming a strongly impressed line at that point; scape and pedicel faintly imbricate. Mesoscutum smooth with small, well-defined punctures separated by 3–6 times a puncture width over most of disc, punctures becoming slightly more dense posteriorly ( Fig. 2 ), separated by 2–3 times a puncture width in posterior third and separated by 1–3 times a puncture width in posterolateral corners and along extreme posterior border; mesoscutellum smooth with punctures similar to those of mesoscutum except slightly more shallow and separated by 0.75–1.5 times a puncture width centrally and 1.0–1.75 times a puncture width along borders; tegula faintly imbricate; metanotum scarcely evidence, represented by a thin strip of integument between mesoscutellum and propodeum; pleura with strongly defined punctures separated by 0.25–1.0 times a puncture width except punctures sparse around scrobe, integument between punctures smooth and shining; propodeum faintly imbricate, lateral surface with shallow, poorly-defined punctures separated by 0.5–1.0 times a puncture width, posterior surface impunctate. Metasomal terga and sterna faintly imbricate except first tergum smooth.

Integument of head and mesosoma dark reddish brown ( Figs. 1–2 ) and shining except labrum, mandible, labiomaxillary complex, scape, and pedicel brown; antennal flagellum light brown; tegula translucent brown; wing veins brown, membrane hyaline; legs brown except tarsi light brown. Metasoma brown.

Pubescence silvery white. Head with scattered suberect to erect, fine, simple setae, intermingled with suberect, plumose setae just above and around antennal toruli and on face below tangent of antennal toruli, such setae not obscuring integument; gena with such plumose setae more numerous; apicolateral corners of clypeus with small patches of tightly packed, elongate, minutely-branched setae, such setae off-white. Mesosomal dorsum with sparse, short, simple setae, largely confined to lateral areas, with short, appressed, plumose setae on anterior-facing lip of mesoscutum, axillar surface, and upper portion of propodeum, both laterally and posteriorly; pleura with scattered suberect, branched setae, such setae not obscuring integument. Metasoma with widely scattered, suberect to erect, short, simple setae, terga apparently without fasciae.

Female. Unknown.

Etymology. The specific epithet refers to the Sahel (a.k.a., Sahel Belt), the semi-arid steppe and savanna bordering the Sahara to the North and the more arid Sudan savanna belt to the South.

Acknowledgements

I am grateful to Dr. Alain Pauly (Institut Royal des Sciences naturelles de Belgique,

Département Entomologie) for recognizing the significance of the specimen and bringing it to my attention, to Mr. Jakub Straka (Charles University in Prague, Czech Republic) and an anonymous reviewer for critiques of the manuscript, and to Mr. Martin Fikáček (National Museum, Prague) for editorial assistance. The line illustrations were prepared by Ms. Kendra R. Koch through support of the Engel Illustration Fund of the College of Liberal Arts & Sciences, University of Kansas. This is a contribution of the Division of Entomology, University of Kansas Natural History Museum.

Figures

Figs.1–2. Photomicrographs of holotype male of Chiasmognathus saheliensis sp. nov. from Niger:1 – facial aspect; 2 – dorsal aspect.

Figs. 3–5. Male terminalia of Chiasmognathus saheliensis sp. nov. from Niger: 3 – sternum VII; 4 – sternum VIII; 5 – ventral aspect of genital capsule. Scale bars = 100 μm.