Macrotomoderus insolitus, Zhao & Wang, 2025

Zhao, Yuchen & Wang, Xinpu, 2025, New species of Macrotomoderus Pic (Coleoptera: Anthicidae) from Southern China, Zootaxa 5660 (3), pp. 389-402 : 391-392

Macrotomoderus insolitus sp. nov. (Ḝ常大OiṚDzş)

Figures. 9–16

Type material designated: Holotype: ♂, Jinyunshan (Ḅ云Ɯ), Chengjiang Township (ȃȗDz), Beibei District (北 %区), Chongqing City ( Þ ẑǖ), China, 24-X-2017, GPS. 106.388197E, 29.840492N, alt. 770 m, leg. Zhizhong Gao (ḕŝae) & Xuyun Gong (ãDz云) ( SANXU).

Measurements. Holotype. Total length 4.11 mm; head length 0.83 mm, head width across compound eyes 0.88 mm; pronotum length 1.11 mm, maximum pronotal width 0.80 mm, minimum pronotal width 0.39 mm, elytra length 2.16 mm, combined maximum elytral width 1.67 mm.

Description. Head, pronotum, and elytra uniformly brown; antennae, maxillary palps, apical tibia and tarsus yellowish-brown, tibia base and femur brown.

Head broadly subtriangular, moderately glossy dorsally and ventrally; eyes medium, moderately convex; Tempora as long as eye length, strongly narrowing towards head base, posterior temporal angle broadly rounded; head base rounded, slightly truncate in dorsal view; punctures on head minute, with intervening spaces glossy and glabrous, much wider than punctures; setae on head whitish to yellowish, distinct, subdecumbent, and directed toward the middle of head; few longer, erect tactile setae scattered on frons and posterior to compound eyes; antennomere III longer than antennomere II and than antennomere IV; antenomeres V to X gradually widen, while antennomeres VII to X are distinctly transverse; terminal antennomere broadly triangular with rounded apex, about 1.5 times as long as penultimate antennomere; Terminal maxillary palpomere broadly triangular to semicircle.

Pronotum (fig. 10) length greater than width, moderately glossy dorsally and laterally, with broad and medially deeply notched postmedian lateral constriction; front margin of anterior lobe broadly rounded, without anterior rim; in dorsal view, lateral pronotal fovea moderately wide, anterior denticles appearing right-angled and posterior denticles obtuse-angled(fig. 10a); cavity in lateral wall of pronotum between lateral denticles moderate; in lateral view, anterior lobe slightly convex; lateral constriction not continues onto disc; lateral pronotal fovea moderately narrow with distinct margin of pronotum, slightly widens upwards towards pronotal disc; anterior and posterior margins of fovea, each protrudes a black broad semicircle denticle, with few setae beneath the two denticles (fig. 10b); pronotal dorsal punctures generally similar to those on head, intervening spaces moderately glossy; constriction area dorsally with dense, large, irregularly circular punctures, separated by much less than puncture diameters; lateral margins of pronotum minutely punctured; pronotal setae yellowish, dense, suberect; with few longer erect tactile setae present along lateral sides of anterior lobe.

Scutellar shield minute, rounded apically.

Elytra dorsally elliptical, slightly flattened in lateral view, widened laterally around midlength, lateral margins evenly broadly rounded, moderately glossy. humeral angle with beak-shaped small nodular, apterous species; punctures circular, much stronger and larger than those on dorsal forebody, smaller and less coarse than dorsal punctures on pronotal constriction, becoming much smaller and sparser on posterior third of elytra; setae yellowish, rather long and dense, suberect.

Each tibia with basal half flattened, fore tibia with blunt angulate expansion near middle on inner side, hind tibia inner edge straight, without distinct curvature.

Male tergite VII broadly rounded at posterior margin, sternite VII shallowly excavated on apical margin, sternite VIII obviously excavated on apical margin; spiculum gastrale and aedeagus as in figures 15 and 16.

Diagnosis. This species superficially resembles the M.gracilicollis species group ( Telnov, 2007)in its specialized elytral humeral angles, tibial morphology, and genital characters. However, it deviates from the diagnostic traits of the group by having a pronotum length not significantly exceeding its width and displaying distinct denticles in dorsal view. The taxonomic placement of this species within the M. gracilicollis species group is provisionally withheld pending further study. The pronotal punctation of M. insolitus sp. nov. is similar to that of M. blinsteini Telnov, 2024 ( China: Sichuan-Shaanxi), but differs in the non-transversely-ovoid head and the presence of a small beak-shaped nodule on the elytral humeral angle (absent in M. blinsteini ).

Etymology. Named from Latin " insolitum ", meaning "unusual" or "extraordinary", referring to the elytral beak-shaped nodule, like members of M. gracilicollis species group.

Distribution. China (Chongqing).

Figures

FIGURES 9–16. Macrotomoderus insolitus sp. nov., holotype. (9) habitus of male; (10) Pronotum, (a) dosal view, (b) lateral view; (11) sternite VII, ventral view; (12) tergite VII, dorsal view; (13) sternite VIII, ventral view; (14) tergite VIII, dorsal view; (15) spiculum; (16) aedeagus, (a) ventral view, (b) lateral view. Scale bar: 1 mm for fig. 9; 0.5 mm for figs. 11–16.