Nitorus mediator, Telnov, 2024

Telnov, Dmitry, 2024, New species and records of Anthicidae Latreille, 1819 (Coleoptera) from Taiwan with a key to Asian Nitorus Telnov, 2007 species with gibbose pronotum, Zootaxa 5507 (2), pp. 285-312 : 286-289

Nitorus mediator sp. nov. ( Figures 1–2 )

urn:lsid:zoobank.org:act:AA1E1C59-31C9-45BE-AF50-CE55A14D72F6

Type material designated. Holotype ♂ BMNH: TAIWAN, Kaohsiung County Jongjhihguan , 131 km post N23°17.229 E120°53.777 12.viii.2008, 1934 m, At light H.Mendel & M.V.L.Barclay BMNH (E) 2008-85 [printed]. The left protibia- and tarsus and the right metatarsomeres 3–4 are missing.

Paratype 1♀ BMNH: TAIWAN, Nantou County 0.5km NW of Lushan N24°01.481 E121°10.876 08.viii.2008, 1268m, at light, M.V.L. Barclay & H. Mendel BMNH (E) 2008-85 [printed] .

Derivatio nominis. Named from Latin ‘mediātor’ (intermediary, mediator).

Measurements, holotype male, total body length 2.8 mm; head length 0.6 mm, head width across compound eyes 0.6 mm, pronotal length 0.6 mm, maximum pronotal width 0.4 mm, minimum pronotal width 0.3 mm, elytral length 1.6 mm, combined maximum elytral width across midlength 0.9 mm. Female paratype 3 mm long.

Description. Head black-brown, pronotum reddish brown. Elytra black-brown, base narrowly reddish brown, postbasal transverse impression with a yellowish rufous transverse band. Antenna yellowish rufous, two terminal antennomeres brown. Maxillary palpus yellowish rufous. Legs brown, basal area of each tibia and trochanters yellowish. Head elliptical, about as long as wide, slightly convex in dorsal aspect, glossy. Labrum subtruncate at anterior margin. Frontoclypeal suture barely indicated, slightly arched. Compound eye moderate, strongly protruding from lateral outline of head, about as long as converging tempus. Head base narrowly rounded. Head dorsal punctures moderate, deep, rather dense between compound eyes, sparse beyond. Intervening spaces smooth and glossy, as wide as (on frons) to 3× as wide as punctures (on vertex). Dorsal cranial setae yellowish, moderately dense, appressed. Antenna extending towards postbasal transverse impression of elytra when directed posteriad, not or hardly thickened in apical half. Antennomere three about 1.4× as long as antennomere two. Antennomeres 4 and 5 about same length, each about 1.1–1.2× as long as antennomere three. Antennomeres 8–9 slightly, penultimate antennomere distinctly widened distally. Terminal antennomere elongate, pointed, about 1.7× as long as penultimate antennomere, distinctly shorter the combined length of antennomeres 9–10. Penultimate maxillary palpomere short, slightly transverse, lobate and long setose at mesal margin. Terminal maxillary palpomere strongly securiform. Cranial ‘neck’ less than one third head width across compound eyes, densely punctured, moderately glossy. Pronotum longer than wide, distinctly narrower than head across eyes, subtruncate medially at anterior margin. Pronotal disc glossy, bigibbose in dorsal aspect with deep, saddle-like discal impression separating anterior and basal lobe of pronotum. Anterior gibbosity smaller and lower, located medially on anterior lobe. Lateral margins of anterior lobe broadly rounded, of basal lobe—subparallel. Anterior pronotal rim distinct, wide dorsally, laterally and ventrally. Antebasal sulcus wide dorsally and laterally. Pronotal punctures smaller and sparser than those on head, intervening spaces glossy and glabrous, generally larger than punctures. Basal lobe with larger and denser (compared to anterior lobe) but shallow punctures, intervening spaces here glossy and glabrous, about as wide as punctures. Lateral sides of anterior lobe glossy and glabrous, nearly impunctured, of basal lobe—glossy and glabrous, with several irregular subparallel longitudinal wrinkles. Pronotal setae as those on head, subdecumbent. Scutellar shield lanceolate, apically rounded, glossy and glabrous, dorsally slightly convex. Elytra elongate, about 1.7–1.8× as long as wide, widest at midlength, dorsally slightly convex in apical two thirds. Postbasal transverse impression shallow but distinct. Humerus broadly rounded. Apical sutural angle rounded. Elytral surface glossy and smooth, dorsal punctures moderate, shallow, moderately dense. Intervening spaces smooth and glossy, about as wide as to wider than punctures. A yellowish, short, slightly curved, nearly appressed seta raises from each puncture. Scattered, longer erect tactile setae on elytral disc. Metathoracic wing fully developed (functional). Legs long and slender, moderately densely, appressedly setose. Tibial terminal spurs appear single, short. Penultimate tarsomeres slightly bilobate. Tergite VII truncate at posterior margin ( Fig. 2A ). Morphological sternite VII broad, rounded at posterior margin ( Fig. 2B ). Morphological tergite VIII rounded, long setose at posterior margin ( Fig. 2C ). Morphological sternite VIII horseshoe-shaped ( Fig. 2D ), sternite IX Y-shaped, arms short, stem sinuous ( Fig. 2E ). Aedeagus as in fig. 2F‒I.

Sexual dimorphism. Female externally similar to male, but antenna comparatively shorter, anterior gibbosity of pronotum in lateral view comparatively stronger developed than that of male. Tergite VII truncate at posterior margin. Morphological sternite VII broadly rounded at posterior margin.

Differential diagnosis. This species differs from N. mediomaculatus ( Pic, 1913) (see the new combination and rescued name below), N. trigibber (Marseul, 1876) and other congeners with strongly bigibbose pronotum in the shape of the aedeagus (also see the Key below). It appears different from N. trigibber also in the distinctly longer antenna (extending towards postbasal transverse impression area of elytra versus towards elytral base in N. trigibber ) and the comparatively stronger elongate elytra.

Ecology. Attracted to light.

Distribution. So far known from mountainous central (Nantou County) and southern (the former Kaohsiung County) parts of Taiwan.

Figures

FIGURE 1. Nitorus mediator sp. nov. A—Paratype ♀, habitus, dorsal view; B—Holotype ♂, habitus, lateral view [not to scale].

FIGURE 2. Nitorus mediator sp. nov., holotype ♂. A—Tergite VII, dorsal view; B—Morphological sternite VII, ventral view; C—Tergite VIII, dorsal view; D—Morphological sternite VIII, ventral view; E—Morphological sternite IX, ventral view; F— Aedeagus; G—ditto, apex, magnified; H—ditto, median portion; I—ditto, internal sac with gonopore armature [not to scale].