Diagnosis.
Zaitzevia longyanensis can be distinguished from all other Chinese species of the genus by the combination of the following characters: body size 2.64–2.90 mm, body elongated obovate, anterior pronotal corners strongly produced and acute, elytral stria I distinctly punctate in basal half, punctures on striae II–IV very large from about basal 0.2–0.5, but more or less obsolete in basal 0.2 and distal 0.5, and elytral apex subtruncate. We are not aware of any described species which might be confused with Z. longyanensis based on external characters. Regarding male genitalia, Z. longyanensis vaguely resembles Z. fodingshana Jiang & Chen, 2025 from Guizhou Province, but it can be distinguished from the latter by the apex of the median lobe being robust in ventral view, by the sclerotizations of the endophallus being well developed from basal 0.10 to distal 0.25, somewhat resembling a bowknot, while in the latter, the apex of the median lobe is slenderer and more acute in ventral view, the slerotizations of the endophallus are rod-like and well developed from subbase to distal 0.35; externally, Z. fodingshana differs significantly from the new species, especially in the much less produced anterior pronotal corners and in the rounded elytral apices.
Description.
Male (holotype). BL 2.90 mm, BW 1.30 mm. Body elongate obovate (Fig. 1A). Colour. Dorsum black, ventral side (Figs 1B, 2B, 2C) dark brown to black, tarsi brown, antennae yellowish-brown.
Head. Labrum transverse, surface smooth and shiny, sparsely punctate and pubescent, anterior margin convex, not emarginate medially, lateral margin with long setal fringe.
Pronotum. PL 0.75 mm, PW 0.93 mm. Pronotum broadest at basal 0.4, slightly narrowed posteriorly, and distinctly attenuate anteriorly, surface smooth and shiny, densely punctate and sparsely pubescent. Anterior corners distinctly produced and sharply pointed, posterior corners almost rectangular. Anterior margin slightly produced anteriad. Median groove narrow and shallow, present in basal 0.1–0.6. Base with two admedian pairs of small granules in front of scutellum. Sublateral carinae extending from base to basal 0.4, distinct, subparallel in basal 0.3, then curved inward, mesally bordered by a groove.
Elytra. EL 2.15 mm, EW 1.30 mm. Elytra subparallel in basal 2/3, distinctly attenuate in distal 1/3, apex subtruncate. Stria I distinctly punctate in basal half, but more or less impunctate in distal half. Punctures on striae II–IV very large in about basal 0.2–0.5, but more or less obsolete in basal 0.2 and distal 0.5. Intervals smooth and shiny, intervals I and III each furnished with a row of minute setiferous punctures. Carinae on intervals V extending from about basal 0.15 to the apex; carinae on intervals VI–VII extending from base to apex.
Ventral side of thorax. Prosternum densely punctate and granulate, with dense yellowish plastron anterior of procoxae (except along midline). Prosternal process unpubescent, gradually narrowed, more or less shiny, with some larger punctures, apex broadly rounded, lateral margin distinctly rimmed. Metaventrite broadly impressed in posterior 0.8, disc smooth and shiny, only with a few small punctures, not pubescent; median groove situated in posterior 0.8, gradually narrowing anteriad, with a pair of very large, admedian basal pits; lateral areas covered by dense plastron, with two transverse rows of large punctures, one behind mesocoxa and one anterior of metacoxa.
Legs. Without distinct sexual dimorphism, largely covered by plastron.
Ventrites. Disc of ventrite I smooth and shiny, with widely spaced fine punctures, admedian carinae strongly developed. Middle of ventrites II–IV, and middle of basal 1/3 of ventrite V smooth and shiny, only with a few fine punctures; lateral parts of ventrites I–IV and lateral parts of ventrite V in anterior 0.4 covered by plastron; distal 0.6 of ventrite V partly punctate and granulate, covered with setae that become increasingly longer towards produced and pointed posterior corners; apex of ventrite V rather distinctly emarginate, concavely impressed and unpubescent between acute corners, which are slightly bent ventrad.
Aedeagus. 1.6 mm long. Median lobe about 2.4 times as long as phallobase, slightly broadened in basal 1/4, then subparallel to distal 1/4, distinctly narrowed in distal 1/4, with a pair of small subapical teeth at apical end of ventral sac; in lateral view, median lobe distinctly curved dorsad apically. Sclerotizations of endophallus well developed, somewhat resembling a bowknot. Parameres not discernible.
Female. Externally, females cannot be easily distinguished from males. On average, posterior part of metaventrite and median groove less distinctly impressed in females. Apical corners of ventrite V only hardly noticeably produced in females, and less strongly impressed between corners.