Cephennodes (s. str.) gusu, Feng & Yin, 2023

Feng, Ting & Yin, Zi-Wei, 2023, A new Cephennodes Reitter (Coleoptera: Staphylinidae: Scydmaeninae) of C. lustricollis group from East China, Zootaxa 5346 (3), pp. 331-336 : 332-335

Cephennodes (s. str.) gusu sp. nov.

( Figs 1 , 2 )

Chinese common name: Mẉẃẅffl

Type material (3 exx.). HOLOTYPE: CHINA: ♁: ‘China: Jiangsu, Suzhou City, Qionglong Mountain , 31°16′4.47″N, 120°25′52.46″E, 105 m, 19.viii.2023, leaf litter, sifted, Ting Feng & Zi-Wei Yin leg., ḢẉẘẉNJm ƯĦffiDzď ’ ( SNUC) . PARATYPES: CHINA: 1 ♁, 1 ♀, same collecting data as for holotype ( SNUC) .

Diagnosis. Male. Body length 1.36–1.38 mm. Anterior portion of vertex and frons with median area covered with relatively denser punctures, which are sparser on lateral and posterior regions. Punctures on pronotal disc fine and sparse, those on elytra as sparse but distinctly larger than those on pronotum. Aedeagus of simonis - type, with elongate apical part of median lobe and broad apical projection pointing towards apex of median lobe, apical margin of projection transverse in relation to long axis of aedeagus. Female. Distinctly larger than male, body length 1.53 mm, external morphology almost identical to that of male, may be identified only by association with simultaneously collected males.

Description. Male. Body ( Fig. 1A, B ) relatively slender, with well-marked constriction between pronotum and elytra, strongly convex, length 1.36–1.38 mm; pigmentation reddish-brown, vestiture slightly lighter than cuticle. Head lacking modifications, small, length 0.18–0.19 mm, width 0.33–0.34 mm, broadest at moderately large but strongly convex and coarsely faceted eyes; vertex and frontoclypeal region confluent, convex; supraantennal tubercles small and weakly raised. Punctures on anteromedian region of frons and vertex relatively denser than other regions of head and becoming sparser and evenly distributed on lateral and posterior areas ( Fig. 1C ); setae relatively long and sparse, suberect. Antennae moderately long, with slender but compact proximal portion and strongly broadened, three-segmented club, length 0.64–0.67 mm; antennomere 1 ca. 1.3× as long as broad, 2 distinctly narrower and slightly shorter than 1, 1.4× as long as broad, 3–6 subequal in width, 5 and 6 slightly longer than 3 and 4, 3–6 each distinctly narrower than 2 and ca. 1–1.2× as long as broad, 7 as broad as 6 but distinctly longer, 1.4× as long as broad, 8 distinctly shorter and much broader than 7, about as long as broad, 9 much broader and longer than 8, slightly broader than long, 10 much larger than 9, slightly broader than long, 11 largest, broader than 10, about as long as 9 and 10 together, subconical.

Pronotum in dorsal view semielliptical in shape, broadest at base, length 0.44–0.45 mm, width 0.57–0.58 mm; anterior and lateral margins in anterior half strongly rounded, in posterior half sides finely micro-serrate, barely noticeably rounded and very weakly converging toward nearly right and acute posterior angles; posterior margin deeply bi-emarginate; lateral carinae narrowly but distinctly separated from lateral margins, extending along posterior 2/3 of pronotum; antebasal pits moderately large and distinct, each located much closer to posterior than to lateral margin of pronotum. Punctures on pronotal disc fine and sparse, evenly distributed; setae long and moderately dense, suberect to erect. Elytra lacking modifications, oval and moderately long, broadest near anterior third, length 0.72–0.75 mm, width 0.61–0.63 mm, length/width 1.18–1.20. Subhumeral lines carinate, short (ca. 0.3× as long as elytra) and only slightly diverging toward lateral margins of elytra; humeral denticles small but distinct; apices of elytra separately rounded. Punctures on elytra evenly distributed, as dense as those on pronotum but slightly larger, with slightly elevated margins, so that cuticle appears more or less coarse; setae slightly longer than those on pronotum, dense and strongly erect. Metathoracic wings fully developed.

Legs moderately slender and long, lacking peculiar characters.

Metaventrite ( Fig. 1B ) without post-mesocoxal impressions, punctures moderately large and very distinct. Aedeagus ( Fig. 1D, E ) small, 0.17 mm in length, simonis - type, with strongly projected and roundly truncate apex of median lobe; apical projection broad, with apex directed towards apex of median lobe; parameres very slender, each with three setae in apical half.

Female. General external morphology similar to male, including elytral vestiture; body distinctly larger, length 1.53 mm; length of head 0.20 mm, width 0.37 mm, length of antenna 0.67 mm; length of pronotum 0.50 mm, width 0.66 mm; length of elytra 0.83 mm, width 0.70 mm, elytra length/width 1.20.

Comparative notes. This species is most similar to C. astoni from Hong Kong in the general habitus and proportions of body parts. They differ mainly in body length (1.36–1.38 mm in C. gusu vs. 1.15–1.24 mm in C. astoni ), punctures on the posterior and lateral regions of the head (uniform and sparsely distributed in C. gusu vs. without punctures in C. astoni ), punctures on the median region of the pronotum and metaventrite (more distinct in C. gusu ), punctures on the elytra (evenly distributed in C. gusu vs. denser and coarser in the anterior half of elytra in C. astoni ), and the shape of the apical projection of the aedeagus (almost straight apical margin in C. gusu vs. slightly and broadly emarginate in C. astoni ). The four known species of the C. lustricollis group can be distinguished by using the identification key given below.

Distribution. East China: Jiangsu ( Fig. 2A ).

Biology. All individuals were collected by sifting moist leaf litter layer in a mixed forest ( Fig. 2B, C ).

Etymology. Noun in apposition. Gusu (Mẉ) is one of the historical names of Suzhou city.

Figures

FIGURE 1. Habitus and morphological details of Cephennodes gusu sp. nov., male. A, B. Habitus, dorsal (A) and ventral (B). C. Head dorsum, showing punctation. D, E. Aedeagus, ventral (D), and lateral (E). Scale bars: 0.5 mm in A, B; 0.2 mm in C; 0.1 mm in D, E.

FIGURE 2. Distribution and habitat of species belonging in the Cephennodes lustricollis group. A. Distribution; triangle–C. lustricollis, circle–C. astoni, square–C. zunyianus, star–C. gusu sp. nov. B, C. General environment (B) and collecting site (C) of C. gusu sp. nov.