Eubadura Sawada, 1990

Lee, Seung-Gyu & Ahn, Kee-Jeong, 2024, Description of a New Korean Coastal Species of Eubadura Sawada (Coleoptera: Staphylininae: Aleocharinae), with Taxonomic Notes, The Coleopterists Bulletin 78 (2), pp. 201-205 : 201-204

Genus Eubadura Sawada, 1990

Eubadura Sawada 1990: 543 (type species: Atheta (Eubadura) akiensis Sawada, 1990 ; as subgenus of Atheta Thomson ).

Osakatheta Maruyama, Klimaszewski, and Gusarov 2008: 40 (type species: Osakatheta yasukoae Maruyama, Klimaszewski, and Gusarov, 2008 ).

Eubadura : Tasaku and Maruyama 2022: 139.

Eubadura yooi Lee and Ahn , new sPecies zoobank.org/ urn:lsid:zoobank.org:act:016CFA91-4D44-4441-8217-251C36510DCD ( Figs. 1A , 2 )

TyPe SPecimens EXamined. Holotype, labeled as follows: “ KOREA: Gyeongnam Prov., Tongyoung-si, Dosan-myeon, Jeosan-ri , N34 ° 53′49″ E128 ° 18′19″, 03 IV 2014, KJ Ahn, under stones on boulder shore; HOLOTYPE Eubadura yooi Lee and Ahn, 2024 ”. Deposited in CNUIC . Paratypes, 4 exx., same data as holotype; 1 ex., KOREA: Gyeongnam Prov., Geoje-si, Jangmok-myeon, Nongso-ri , Nongso-beach , N35 ° 00′ 14″ E128 ° 42′04″, 15 VI 2014, IS Yoo, 10–30 cm deep under pebbles on pebble beach; 5 exx., KOREA: Gyeonggi Prov., Incheon-si , Ganghwa-gun , Gyodongmyeon , Dongsan-ri , N37 ° 45′30.19″ E126 ° 14′28.96″ 2m, 12 VI 2019, IS Yoo, JS Lee, under stones on mud flat in low-mid tide .

DescriPtion. Length 2.6–2.8 mm. Body ( Fig. 1A ) covered with long, dense, erect setae; robust and voluminous; head, pronotum and abdomen black to dark brown; antennae, elytra, and legs dark brown to brown. Head. Subcircular, about as wide as long, widest at middle, slightly narrower than pronotum; eye small, about 0.6 times as long as temple; gular sutures moderately separated, diverged basally; in- fraorbital carina absent; cervical carina incomplete; occipital carina present. Antenna moniliform, almost reaching to the end of elytron; antennomeres 1–5 elongate, 1 longest, 2 almost as long as 3, 4 and 5 shorter than 3, 6–7 subquadrate, 8–10 slightly transverse, 11 longer than wide, slightly shorter than preceding two combined. MouthParts. Labrum transverse, anterior margin slightly rounded, with ε-sensillum and 8 macrosetae on each side of midline; epipharynx with several sensilla; α-sensillum long and setaceous; β- and γ-sensilla reduced. Mandibles asymmetrical, subtriangular, decurved and pointed at apex, about 1.4–1.5 times as long as basal width, internal margin slightly serrulate; very few small denticles present in molar region; right one with small internal tooth; prostheca developed, composed of three portions. Galea and lacinia of maxilla long and slender; lacinia with seven spines in distal comb region, two isolated spines present; maxillary palpus elongate and pubescent; palpomere 1 smallest, 2 about 3.0 times as long as 1, 3 longer than 2, more-or-less spindle shaped, 4 digitiform, filamentous sensilla reaching to basal half. Labium with ligula divided into two lobes in basal third to half; prementum with two medial setae moderately separated; basal pores absent; with numerous median pseudopores, few lateral pseudopores and one setal pore and two real pores present on each side of midline; labial palpus elongate, with many setu- lae; palpomere 1 largest, about 1.5 times as long as wide, 2 almost as long as wide, 3 parallel-sided and slightly shorter than 1, about 3.0 times as long as wide. Mentum trapezoidal, anterior margin emargi- nate; v-seta more-or-less equal distance from u- and w-seta. ThoraX. Pronotum slightly transverse, about 1.2 times wider than long, widest in apical third, with about six macrosetae on lateral margin; anterior and posterior margins rounded; pubescence directed anteriorly and antero-laterally; hypomeron fully visible in lateral aspect. Metanotal scutum with one seta and about 3–4 minute setae on each side of midline. Mesoventral process slightly pointed at apex, reaching middle of mesocoxa, mesocoxal cav- ity not margined; metendosternite Y-shaped. Elytra slightly transverse, wider than pronotum; elytron about 1.5–1.6 times as long as wide, pubescence directed posteriorly and postero-laterally; posterolateral margin slightly sinuate; hind wings reduced, longer than elytron. Legs slender and moderately long, with pubescence and macrosetae; tibiae with different length of two spurs at apex; tarsal formula 4-5-5, length ratio of tarsomeres 21:22:21:61 (front tarsus); 20:15:17:16:43 (middle tarsus); 23:18:11: 11:27 (hind tarsus); tarsal setae particularly long. Abdomen. Broadened posteriorly and convergent at apex, slightly narrower than elytra; widest at segment VI; surface glossy, with densely erect setae and imbricate microsculpture; tergites III–V impressed in basal region, VI slightly impressed in basal region; male tergite VIII ( Fig. 2A ) with four macrosetae on each side of midline, posterior margin subtruncate; male sternite VIII ( Fig. 2B ) with seven macrosetae on each side of midline, posterior margin rounded, with long marginal setae; posterior margin of female tergite VIII and female sternite VIII similar to male but slightly shorter. Aedeagus. Median lobe ( Figs. 2C, D ) with apical process abruptly narrowed apically and convergent at apex in ventral aspect; distinct internal sclerites present. Apical lobe of paramerites ( Fig. 2E ) elongate and slightly bent, with four setae; a-seta longest and about as long as b-seta; c- and d-setae distinctly short and close together, positioned apically.

SPermatheca. Bursa without umbilicus; duct slen- der and coiled at apex ( Fig. 2F ).

Distribution. Korea (South).

Etymology. Named after In-Seong Yoo who collected this new species and studied many Korean coastal staphylinids.

Remarks. This species is extremely similar to Eubadura yasukoae (Maruyama, Klimaszewski, and Gusarov) in external morphological characters but can be distinguished by the different form and internal structure of male genitalia ( Figs. 2C, D ) as characters provided in the key below. The validity of the new species is further supported by partial COI gene sequences (Jung and Ahn, unpublished data). The genetic diver- gence of COI (331 bp) based on uncorrected p-distance was 11.8% between E. yooi and E. yasukoae and 5.4% between the new species and E. hokkaidensis .

Tasaku and Maruyama (2022: 139) provided a key to species of Eubadura . Herein, we add a cou- plet to include E. yooi as follows:

3. Pronotum widest around anterior two-fifths; duct of spermatheca about 5 times as long as capsule......................................................... 4

3′. Pronotum widest around anterior one-third; duct of spermatheca about 3 times as long as capsule........................... E. onoi Tasaku and Maruyama

4. Median lobe of aedeagus narrower in basal third in lateral view; apical process of median lobe longer in lateral view ( Maruyama et al. 2008: fig. 28) and gradually narrowed in ventral view ( Maruyama et al. 2008: fig. 29) ............................. E. yasukoae (Maruyama, Klimaszewski, and Gusarov)

4′. Median lobe of aedeagus broader in basal third in lateral view; apical process of medi- an lobe shorter in lateral view ( Fig. 2C ) and abruptly narrowed in ventral view ( Fig. 2D ) ............... E. yooi Lee and Ahn , new sPecies

Figures

Fig. 1. Habitus.A) Eubadura yooi, new sPecies, 2.8 mm, B) E. hokkaidensis, 2.2 mm.

Fig. 2. Eubadura yooi, new sPecies. A) Male tergite VIII, dorsal view, B) Male sternite VIII, ventral view, C) Median lobe, lateral view, D) Median lobe, ventral view, E) Paramere, lateral view, F) Spermatheca (capsule shrunk). Scales = 0.1 mm.