Tribasodites sugayai, Inoue & Maruyama, 2020

Inoue, Shota & Maruyama, Munetoshi, 2020, A new termitophilous species of Tribasodites Jeannel from Taiwan and southern China (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 4786 (3), pp. 417-424 : 418-421

Tribasodites sugayai sp. nov.

( Figs 1–3 )

Type material. Holotype, (deposited in NMNS): ♂, “ TAIWAN: / Nantou, Tehuashe (1200m) / 12–15 II 2002, / SU- GAYA H leg.” ( HS) ; Paratypes, 18♂, 27♀, same data as holotype (13♂, 22♀ in KUM; 5♂, 5♀ in NSMT) ; 1♂, 1♀, Taiwan, Nantou, Renai, Huisun , Tang Monument , 14 IV 2018, W. R. Liang leg. ( HS) ( NMNS) ; 1♂, China: Fujian, Nanping (ḢỸḿ), Mangdang Mt. ( ËƋƜ) , Sanqianbabaikan (ĽTĀƀẉ), 800 m, 12 XI 2017, decomposing log, Xing-Qiu FAN leg. ( SNUC) .

Diagnosis. This species is readily distinguished from other Tribasodites species by the following characteristics: head with elaborate crowns in the male; antennae unmodified in both sexes; pronotum with small lateral spines; metasternum with longitudinal sulcus along the midline; metacoxae and metatrochanters simple, lacking spines; aedeagus bulbous in shape, lacking basoventral projection.

Aedeagus of other Tribasodites species usually elongate and bears ventral projection, while aedeagus of the new species is bulbous and lacking basoventral projection. This morphology is similar to that of T. tianmuensis . However, the new species has aedeagus with median lobe weakly constricted at middle and with basal foramen smaller than in T. tianmuensis .

Description. Male ( Figs 1A, D ). Body length 2.80–3.01 mm. Body reddish brown; dorsal surface covered with densely long setae.

Head ( Fig. 2A ) about as long as wide, HL 0.55–0.65 mm, HW 0.58–0.63 mm, nearly trapezoidal in dorsal view, weakly shining; frons narrowed, weakly prominent antennal tubercles present on anterolateral side, pair of lateral postantennal carina extending from posterior margins of antennal tubercles toward postocular margins, pair of ocular-mandibular carinae present; vertex broad, pair of large, curved carina extending from anterolateral side to posterior base to form a crown; vertexal foveae indistinct; crowns weakly curved laterally at anterior base; eyes prominent; postocular margin 2.5 times longer than eyes; occiputs with dense long setae; antennae ( Figs 1E , 2E ) slender; antennomeres I each twice as long as wide, 1.5 times as long as antennomeres II, nearly subcylindrical, excavated on apical part; antennomeres II–X each elongate; antennomeres II each rectangular; antennomeres III–VII each broadened apically; antennomeres VIII small, 2/3 times longer than VII; antennomeres IX–X each ovoid, thickened at middle, about as wide as antennomeres II; antennomers XI as wide as antennomere I at middle, longest, lanceolate; maxillary palpi each large; segments I each minute; segments II each elongate, pedunculate with anterior third broadened; segments III each small, nearly triangular; segments IV each longest, predominately large, nearly fusiform.

Pronotum ( Fig. 2B ) about as long as wide, PL 0.60–0.65, PW 0.60–0.68 mm, bearing pair of short lateral spines at middle, broadened posteriorly to middle and constricted just behind lateral spines, pair of large fovea present beside constriction, pair of antebasal spines present, pair of longitudinal carina extending from anterior 1/3 to antebasal spines, pair of lateral longitudinal sulcus extending from anterior margin to large foveae, large sulcus present along midline, 4/5 times as long as pronotal length; two pairs of small fovea on posterior base; elytra ( Fig. 2C ) wider than long, EL 0.88–0.98 mm, EW 0.93–1.03 mm, broadened posteriorly from anterior margin to middle, narrowed posteriorly from middle to posterior margin, slightly angulate at anterolateral part; anterior margin 1/2 times as long as posterior margin; three pair of small fovea on anterior base, pair of lateral fovea present on anterolateral side just below anterolateral angulated part in lateral view, with transverse sulcus from lateral foveae to basal 1/ 3 in lateral view; metasternum ( Fig. 1C ) sulcate along midline; profemora slightly thicker than meso- and metafemora; mesofemora as thick as metafemora; protibiae as long as mesotibiae; metatibiae 1.2 times longer than pro- and mesotibiae; dense setae at apex of each tibia; tarsi ( Fig. 2F ) with tarsomeres II as long as tarsomeres III, each with single large claw.

Abdomen ( Fig. 2D ) about as long as wide, AL 0.70–0.80, AW 0.80–0.89 mm, successively narrowed posteriad; tergite IV longest, basal impression divided into three parts; median part slightly narrower than lateral parts; tergite VIII ( Fig. 3D ) transverse, anterior margin strongly concave, setae sparse; sternite VIII ( Fig. 3E ) transverse, posteromedian part with round projection, covered with dense setae.

Aedeagus ( Figs 3 A–C) sclerotized, asymmetrical; basal foramen large; basal bulb broad, narrowed apically; parameres membranous; ventroapical lobe broad; right part longer than left part, elongate, narrowed apically; dorsoapical lobe shorter, more slender than ventroapical lobe in lateral view, nearly triangular in dorsal view; endophallus elongate, broadened at middle, arcuate at apex.

Female ( Fig. 1B ). BL 2.80–2.95 mm; HL 0.53–0.63 mm; HW 0.58–0.65 mm; PL 0.60–0.63 mm; PW 0.59–0.65 mm; EL 0.88–0.93 mm; EW 0.90–1.00 mm; AL 0.73–0.80 mm; AW 0.80–0.88 mm. Head with a pair of vertexal fovea; vertexal sulcus u-shaped.

Remarks. Tribasodites frontalis and T. abnormalis exhibit secondary sexual character on the head. The head of the former is transversely sulcate just anterior of posterior margin, and the head of the latter with tuft of dense setae at vertex. Those sexual character are similar to that of the members of Sinotrisus Yin & Li, 2010 . However, the secondary sexual character states of this new species may have not been reported in other pselaphine species.

Etymology. The new species is named after Dr. Hiroshi Sugaya, who collected the holotype.

Distribution. Taiwan (Nantou); South China (Fujian)

Biology. This species has been repeatedly collected from Hodotermopsis sjostedti termite nests in Taiwan. One specimen from southern China was collected in a decomposing log with termites and ants.

Figures

FIGURE 1. Tribasodites sugayai sp. nov. A, B. Dorsal habitus. A. Male; B. Female; C. Male metasternum; D. Lateral habitus of male; E. Left antenna of male in dorsal view. Scale bars: 1.0 mm in A, B, D; 0.5 mm in C, E.

FIGURE 2. SEM images of Tribasodites sugayai sp. nov., male. A. Head; B. Pronotum; C. Elytra; D. Abdomen; E. Left antenna; F. Left protarsus. Abbreviations: lsp = lateral spine; abs = antebasal spine. Scale bars: 0.5 mm in C, D; 0.3 mm in A, E; 0.25 mm in B; 0.1 mm in F.

FIGURE 3. Details of Tribasodites sugayai sp. nov., male. A–B. Aedeagus; A. Dorsal; B. Ventral; C. Lateral; D. Tergite VIII; E. Sternite VIII. Scale bars: 0.2mm.