Ceresium cylindrithorax, Yokoi, 2019

Ceresium cylindrithorax View in CoL sp. nov. Figs 11, 23A- D

Type. Holotype ♀: “N-SUMATRA; Aik Tarum, Diehl 1.I.” ( ZSM).

Diagnosis. Medium sized, flavo-fulvum, with cylindrical pronotum. Resembles C. detanii Yokoi, 2015 from Bali, differing mainly in the integument of pronotum.

Etymology. The name of this new species refers to its characteristic prothorax.

Description

Measurements. TL= 10.3 mm; EL/EW =2.90; HW/ PW = 0.98; PL/PW = 1.30; PA/PW = 0.86, PB/PW =1.0.

Colour. Reddish brown. Legs paler in colour. Elytra and antennae yellowish brown. Eyes darker.

Head. Similar to that of C. detanii in outline; lustreless; similarly clothed with hairs; more shallowly punctured. Vertex with deeper elliptical punctures. Eyes and antennae similar.

Pronotum. Similarly cylindrical as in C. sibuyanum sp. nov.; a little longer than in C. detanii . Sides feebly emarginated in double-sinuate line; constricted near apex. Disc uneven; surface lustreless; sparsely provided with large though very shallow and obtuse punctures; shallowly scabrous-rugose in part; hairs on disc somewhat resembling those of C. subfuloum Holzschuh, 2015 ; though the hairless area in the middle more extensive and the apical and dorsal pairs of hairless elevations much larger.

Scutellum triangular; pale yellowish pubescent.

Elytra. A little shorter than those of C. detanii , longer than of C. subfuloum .

Legs. Similar as in C. detanii .

Venter. Similar. Prosternum obtusely punctured. Mesosternum extensively nitid.

Abdomen. Similar, 5 th visible sternite with apex broadly rounded.

Female genital organs as in Figure 23A- D. 8 th sternite and 8 th tergite both squarish in outline. 8 th tergite provided with several long and stout setae on apex. 9 th abdominal sternite moderately long; coxite a little longer than paraproct; coxital lobe well sclerotized; furnished with several hairs of medium length. Spermatheca composed of thick shagreened membrane; shaped like a comma mark. Spermathecal duct extremely expanded at the base of spermatheca to form a spherical enlargement, which is longer than and three times as wide as spermatheca itself; surface thick, leathery, shagreened and wrinkled.

Fig. 21. Ceresium gibbicolle sp. nov., holotype Ƌ, genital organs. A -C. Median lobe; A. dorsal view; B. lateral view;

C. ventral view. D -E. tegmen; D. dorsal view; E. ditto, lateral view. F -H. ejaculatory duct complex; F. dorsal view; G. lateral view; H. ventral view. I. 8 th sternite with 8 th tergite in the background, ventral view. Scale bars: 0.5 mm for F,G,H; 1.0 mm for the others.

Distribution. N. Sumatra, Indonesia.

Comparative notes. Of the flavo-fulvum coloured species of Ceresium , solely C. detanii , C. gracile and C. sibuyanum sp. nov. have a cylindrical prothorax like this new species. However, they differ distinctly regarding puncture, hairs and maculation on pronotal disc. It is also comparable, to a lesser degree though, to C. subfuloum from Borneo, sharing the fundamental colouration pattern in common.Pronotum of the latter is, however, shorter, less cylindrical, more extensively punctate and setose.

The extremely large spherical expansion of spermathecal duct at the base of spermatheca, as found in the holotype, is remarkable.

Remarks. Holotype was found among “indet.” specimens in “Hüdepohl Collection” (ZSM).