Ichthyurus terminalis Y. Yang, Lin & X. Yang, 2025

Ichthyurus terminalis Y. Yang, Lin & X. Yang sp. nov.

Figs 6 G View Figure 6 , 10 D View Figure 10 , 16 A ‒ B View Figure 16 , 17 View Figure 17 , 18 A ‒ D View Figure 18

Type material.

Holotype. China. Yunnan • ♂ ( IZAS), Xishuangbanna, Damenglong , 650 m alt., 11. VII. 1958, Yiran Zhang leg.

Paratype. China. Yunnan • 1 ♀ ( IZAS), same locality as holotype, 9. VII. 1958, Leyi Zheng leg. • 1 ♀ ( IZAS), same locality as holotype, 9. VII. 1958, Chunpei Hong leg.

Differential diagnosis.

This species could be easily distinguished from all others of Ichthyurus by the characteristic terminal abdominal sternite VIII (Fig. 17 C View Figure 17 ) and IX (Fig. 17 F View Figure 17 ) of male, proctiger and paraproct (Fig. 17 E View Figure 17 ), as well as structures of aedeagus (Fig. 18 A ‒ D View Figure 18 ).

Description.

Body length: 8.0‒ 8.6 mm, (8.0 mm in holotype); body width: 1.5‒1.7 mm ( 1.5 mm in holotype).

Male (Fig. 16 A View Figure 16 ). Colouration. Body black, head yellow before antennal sockets, antennomeres I ‒ III yellow, prosternum yellow, pronotum yellow with a large black marking extending to middle of anterior margin and anterior parts of lateral margins, scutellum yellow, elytra with a large X-form yellow marking occupying around humeri, along suture and near to apices, legs yellow at trochanters and basal parts of femora and metatibiae, abdomen yellow posteriorly and laterally.

Eyes strongly protruding, interocular distance approximately half as wide as the diameter of an eye. Antennae extending to posterior margin of abdominal tergite II, II ca. 1 / 3 length of I, III ‒ XI subequal in length and approximately twice longer than II.

Pronotum 1.1 times wider than long, anterior margin arcuate, lateral margins feebly diverging posteriorly, posterior margin bisinuate, anterior angles subrounded, posterior angles nearly rectangular.

Elytra 1.3 times longer than wide, 1.8 times longer than pronotum, with lateral margins slightly sinuate, sutural margins distinctly sinuate and moderately dehiscent from the base 1 / 3 part, distance between sutural margins twice as wide as apical width of an elytron, apices rounded.

Pro- and mesofemora slightly swollen (Fig. 16 A View Figure 16 ), protibiae shallowly excavated at inner 2 / 3 part (Fig. 16 A View Figure 16 ); metathoracic legs slender and simple.

Terminal abdominal tergite (Fig. 17 A View Figure 17 ) 1.4 times longer than wide, with postero-lateral projections approximately half length of the tergite, feebly sinuate at inner margins, feebly arcuate at outer margins. Proctiger (Fig. 17 E View Figure 17 ) reniform and laterally sclerotised, protruding over paraproct; paraproct (Fig. 17 E View Figure 17 ) strongly developed, trapezoidal, with posterior angles acute and strongly projecting posteriorly and anterior angles projecting laterally.

Terminal abdominal ventrite (Fig. 17 C View Figure 17 ) peltate, ca. 1.5 times as long as wide, fissured in middle of apical 1 / 4 part, with lateral lobes straight at inner margins, sinuate at outer margins, rectangular at outer apical angles, strongly protuberant and acute at inner apical angles, with a pair of short and conical protrusions near outer apical angles, each protrusion with a tuft of stout setae at apex.

Abdominal sternite IX (Fig. 17 F View Figure 17 ) weakly sclerotised and narrowed posteriorly, short and 1.2 times as long as wide, with posterior margin rounded and confluent with anterior right and left angles, anterior left angle triangular and right angle moderately protruding anteriorly.

Aedeagus (Fig. 18 A ‒ D View Figure 18 ): right paramere compressed laterally, elongate and tapered apically (Fig. 18 B, C View Figure 18 ); left paramere compressed laterally, horn-shaped, acute at apex, approximately as long as right paramere (Fig. 18 B, C View Figure 18 ); setifore extension well-developed and conical, 4 / 5 length of left paramere (Fig. 18 B, C View Figure 18 ); median lobe extremely long, ca. 4.0 times longer than tegmen, even in width along whole length (Fig. 18 A ‒ D View Figure 18 ).

Female (Fig. 16 B View Figure 16 ). Similar to males, but body larger, eyes less protruding, prothoracic legs simple; abdominal tergite VIII (Fig. 17 B View Figure 17 ) ca. 1.5 longer than wide, with postero-lateral projections ca. 2 / 5 length of the tergite and straight at inner margins; abdominal sternite VIII (Fig. 17 D View Figure 17 ) ca. 1.2 times as wide as long, widest near middle, rounded at lateral margins and confluent with outer apical angles, nearly straight at posterior margin. Internal organs of female reproductive system (Fig. 10 D View Figure 10 ): bursa copulatrix tail-shaped at apex; accessory gland even in width at apical half part.

Etymology.

The specific name is derived from the Latin terminus (an end), referring to its characteristic terminal abdominal ventrite.

Distribution.

China ( Yunnan).