Ceresium balkei, Yokoi, 2019

Ceresium balkei View in CoL sp. nov.

Figs 4A- C, 16A- I

Types. Holotype Ƌ: “Espana Sibuyan Is. Romblon, Philippines ”, 1979-1980, P. Witzgall et local collector leg. ( ZSM) . – Paratypes: 3 ƋƋ, ditto ( ZSM) .

Diagnosis. Resembles C. zeylanicum in body structure in general. Smaller-sized; more extensively testaceous. Pronotum regularly punctured, weakly setose. Median lobe broad in dorsal view.

Etymology. The name of this species is dedicated to Dr. Michael Balke, curator of Coleoptera at the ZMS.

Description

Measurements. TL = 9.8-10.5 mm; EL/EW = 2.70- 2.85 (M 2.76); HW/PW = 0.94-0.96 (M 0.95); PL/ PW = 1.12-1.24 (M 1.2); PA/PW= 0.7-0.78 (M 0.75); PB/PW =0.92-0.96 (M 0.95).

Colour. Testaceous; elytra, abdomen, scape and base of femora paler.

Head. Similar to that of C. zeylanicum , though frons less densely punctured.

Pronotum. Longer than wide, with apex distinctly narrower than base. Sides arcuate. Disc dorsally flattened, punctured as in C. mediocre Holzschuh, 2011 though punctures coarser (Fig. 4B); sparsely clothed with pale hair.

Scutellum bell-shaped, whitish tomentose.

Elytra. Similar as in C. zeylanicum , though surface shinier and less deeply punctured.

Legs. Similar as in C. zeylanicum .

Venter. Prosternum with several very large punctures near middle; provided with a pair of extensive, densely punctured depressions each stretching toward side (Fig. 4C); clothed rather sparsely with pale, short, erect, disarrayed hairs. Prosternal process narrow, truncated on apex. Mesosternum concave in the apical middle; thickly furnished with pale, recumbent hairs near sides. Mesosternal process flat and broad, bi-lobed in apical third. Metasternum sparsely clothed with pale, short, recumbent hairs; more densely so on sides and apex.

Abdomen. 5 th visible sternite short; apex very widely emarginated.

Genital organs as in Figure 16A- I. Median lobe about 3 / 8 the length of abdomen; very broad in dorsal view, slender and arcuate in profile; dorsal plate parallel-sided, gradually narrowed in apical sixth and rounded at apex, dehiscent in basal 3 / 5; ventral plate longer than dorsal plate, rather suddenly narrowed toward apex; dehiscent in basal 4 / 5; median struts apicad dilated.Tegmen 7 / 8 the length of median lobe with parameres broad in dorsal view and thick in profile; with long setae on apex. Ejaculatory duct complex in Figure 16F- H; large, nearly half as long as median lobe; ejaculatory duct itself anchored to a sclerotized loop; apical sclerite bi-lobed with each lobe strongly and sharply hooked; basal sclerite slender and elongated. 8 th sternite bi-lobed, with apex widely and deeply emarginated in semi-V-form; clothed with medium to long setae in the apical half. 8 th tergite a little wider than the corresponding sternite; bell-shaped; slightly emarginated on apex; with short, stout setae near apex.

Distribution. Sibuyan Is., Romblon Province, Philippines.

Comparative notes. This new species resembles C. zeylanicum regarding the body structure in general. Pronotum of the latter is, however, obviously less regularly punctured and much more setose. The puncture on pronotum of the new species resembles rather that of C. mediocre , whose pronotum is, in turn, shorter and more setose.Further, it can be compared to C. lingafelteri Vives, 2013 from the nearby island Luzon. It lacks, however, the remarkable band on elytra, and its pronotum differs in outline and integument. As for male genital organs of the new species, median lobe is distinctly wider and the 8 th sternite much more deeply emarginated on apex than those of the other species examined.