Centrophthalmus sinensis Raffray, 1904

Feng, Ting & Yin, Zi-Wei, 2023, Redescription and a new record of Centrophthalmus sinensis Raffray, 1904 (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 5278 (1), pp. 195-200 : 196-200

Centrophthalmus sinensis Raffray, 1904

( Figs 1–3 )

Centrophthalmus sinensis Raffray, 1904: 495 (key, description); Kurbatov 2007: 292 (distribution); Nomura & Idris 2008: 57 (distribution); Schülke & Smetana 2015: 449 (catalog); Newton 2022 (online catalog).

Chinese common name: +ẸDZẈḎƤ

Material examined. 1 ♁, 4 ♀♀, ‘ China: Jiangsu, Suzhou City, Wuzhong Dist., Guangfu To., Tongjing Mt. , 31°17’20.83”N, 120°21’34.63”E, 72 m, leaf litter, 12.iii.2023, Ting Feng leg., ĿNJae+IJKAEDzfflffffi, ṊḆ ※ ’ ( SNUC).

Diagnosis. Male. Body moderately elongate, length approximately 1.8 mm. Head sub-truncate at base, as wide as pronotum, tempora short, densely setose, vertexal and frontal foveae asetose, small, with spinose ocular canthi and densely setose antennal cavities; antenna elongate, swollen antennomeres 8–11 forming distinct club. Pronotum with setose disc, with small, setose median antebasal fovea. Discal striae of elytra broad and shallow, extending posteriorly to approximately 5.7/10 of elytral length; disc finely punctate and with long pubescence. Legs almost simple, only metatrochanter with bluntly angulate ventral margin. Abdomen with tergite 2 (V) twice as long as 1 (IV), discal carinae of tergite 1 curved and complete, those of 2 extending posteriorly to half tergal length. Aedeagus moderately elongate, dorso-ventrally symmetric; median lobe gradually narrowing from base toward apex, endophallus armature composed of broad, elongate sclerite, and with small hook at apex. Female. Body length approximately 1.9 mm. Antenna lacking modification. Ventral margin of metatrochanter flat.

Redescription [based on population of Jiangsu]. Male. Body ( Fig. 1A ) length 1.83 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with dense pubescence.

Head ( Fig. 1B ) sub-truncate at base, broader than long, length 0.34 mm, width across eyes 0.41 mm; vertex with widely separated asetose foveae (dorsal tentorial pits); tempora short, rounded, densely setose; frons anteriorly forming distinct rostrum, with small, asetose frontal fovea, antennal tubercles weakly convex, cavities broad and densely setose; clypeus connecting with frons by distinct median ridge, with smooth surface, its anterior margin moderately carinate and weakly raised; ocular-mandibular carinae thin and faint, ocular canthi forming distinct spine. Venter with smooth surface; tiny gular foveae (posterior tentorial pits) moderately separated, lacking median carina or sulcus. Compound eyes prominent, each composed of 22 large ommatidia. Maxillary palpus ( Fig. 2A ) with palpomere 1 small, 2 basally pedunculate and broadened apically, 3 greatly expanded at anterolateral margin, 4 fusiform, narrowing from basal 1/5 toward apex, 2 and 4 covered with apically enlarged sensory setae. Antenna elongate, length 1.07 mm, distinct club formed by enlarged apical four antennomeres ( Fig. 1C ); antennomere 1 thick, subcylindrical, 2–7 each moniliform, 8 to 10 subequal in length (0.12 mm), gradually broadened, 11 largest, suboval, twice as long as 10 (0.23 mm).

Pronotum ( Fig. 1B ) slightly broader than long, length 0.37 mm, width 0.41 mm, widest anterior to middle; lateral margins rounded, convergent apically and basally; disc weakly convex, finely punctate and densely setose, with small, setose median and lateral antebasal foveae, lacking carina, sulcus or spine. Prosternum with anterior part shorter than coxal part, with distinct, setose and widely separated procoxal foveae; hypomera fused with sternum, smooth; margin of coxal cavity thinly carinate.

Elytra with long pubescence, much wider than long, length 0.43 mm, width 0.69 mm; each elytron with two moderately large, asetose basal foveae; discal impression broad and shallow, extending posteriorly from outer basal fovea to approximately 5.7/10 of elytral length; humeral denticle absent, humeri flat, lacking subhumeral fovea or marginal stria; posterior margin with row of dense setae. Metathoracic wings fully developed.

Mesoventrite short, demarcated from metaventrite by oblique carinae lateral to mesocoxal cavity; median mesoventral foveae narrowly separated, originating from shared setose, transverse opening, large lateral mesoventral foveae broadly forked internally, with short, blunt mesoventral process. Metaventrite weakly projected admesally, slightly impressed at middle, with large, setose lateral mesocoxal foveae and one median metaventral fovea, posterior margin narrowly emarginate at middle.

Legs moderately elongate, almost entirely simple, only metatrochanter ( Fig. 2B ) bluntly angulate at ventral margin.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.66 mm, width 0.72 mm. Tergite 1 (IV) at middle half as long as 2 (V), with deep, setose basal sulcus and one pair of basolateral foveae, with complete, curved discal carinae ( Fig. 2C ); tergite 2 longest, basally impressed and with one pair of basolateral foveae, discal carinae ( Fig. 2C ) extending posteriorly to approximately half of tergal length; tergite 3 (VI) and 4 (VII) subequal in length, each with one pair of small basolateral foveae, 4 with narrow impression at base; tergite 5 (VIII) semicircular, transverse, posterior margin roundly emarginate at middle. Sternite 2 (IV) half as long as 3 (V), 4 (VI) and 5 (VII) each short at middle, 2 to 4 basally sulcate, 2 to 5 each with one pair of basolateral foveae, sternite 6 (VIII) greatly transverse, posterior margin broadly emarginate, sternite 7 (IX) ( Fig. 1D ) elongate, setose and sclerotized at apex.

Aedeagus ( Figs 1E, F , 2D ) 0.37 mm long, dorso-ventrally symmetric, moderately elongate; median lobe with large basal capsule, narrowing from base toward apex, endophallus armature well-developed, composed of single elongate, broad and sinuate sclerite ( Fig. 2D ), which bears one small hook at apex.

Female. Similar to male in external morphology. Antenna shorter, antennomeres 8–10 small, not swollen. Compound eyes each composed of approximately 20 large ommatidia. Metathoracic wings fully developed. Metatrochanter flat, lacking angular expansion. Measurements (as for male): body length 1.88–1.91 mm; length/ width of head 0.35–0.36/ 0.41–0.43 mm, pronotum 0.38–0.40/ 0.43–0.45 mm, elytra 0.49–0.50/ 0.74–0.77 mm; abdomen 0.70–0.72/ 0.78–0.84 mm; length of antenna 1.03–1.05 mm. Genital complex membranous.

Comparative notes. This species is morphologically similar to C. helferi Blattný from Myanmar and Vietnam by the long tergite 2. Externally they can be separated by the relatively shorter male antennomeres 7, and a more densely setose pronotal disc of C. sinensis .

Bionomics. All individuals were collected by sifting leaf litter (lower moist layer) in a mixed secondary forest ( Fig. 3C, D ).

Distribution. The species was originally described from ‘Mong-Po’, China, and was later recorded from Guangxi and Vietnam ( Kurbatov 2007; Nomura & Idris 2008). According to Schülke & Smetana (2015) and Newton (2022), the known distribution also includes Fujian and Taiwan of China, and Thailand. However, the species was not included in Nomura et al. (2008a), and subsequent references ( Nomura et al. 2008b, 2010, 2013) documenting the Thai pselaphine fauna. Here, the species is newly recorded from Jiangsu, China ( Fig. 3A, B ) (new provincial record).

Figures

FIGURE 1. Habitus and morphological details of Centrophthalmus sinensis, male. A. Dorsal habitus. B. Head and pronotum. C. Antennal club. D. Sternite 7 (IX). E. Aedeagus, lateral. F. Endophallus armature, dorsal. Scale bars: 0.5 mm in A; 0.2 mm in B, C, E, F; 0.1 mm in D.

FIGURE 2. Morphological details of Centrophthalmus sinensis, male. A. Maxillary palpus. B. Metatrochanter. C. Abdomen, showing discal carinae of tergite 1 (IV) and 2 (V). D. Aedeagus, ventral. Scale bars: 0.1 mm in A, B; 0.2 mm in C, D.

FIGURE 3. Distribution and environment of Centrophthalmus sinensis. A, B. Maps showing the distribution of C. sinensis in Suzhou. C. General environment. D. Collecting site; the senior author was sifting leaf litter in a mixed secondary forest.