Journal 
1. INTRODUCTION
Genus ScymnusKugelann, 1794, a group of small, pubescent coccinellids, comprises more than 800 described species worldwide (Chen et al. 2015). Members of the genus Scymnus are aphidophagous predators and are considered potential biological control agents (Sebastiao et al. 2015;Bouvet et al. 2019). Eight subgenera are currently recognized within this genus: ScymnusKugelann, 1794;Pullus Mulsant, 1846; Didion Casey, 1899; NeopullusSasaji, 1971;Parapullus Yang, 1978; Mimopullus Fürsch, 1987; Orthoscymnus Canepari, 1997; and Canalipullus Lafer, 2000. Historically, genus Scymnus has been placed in the tribe Scymnini, which was formerly included in the subfamily Scymninae (Korschefsky 1931;Sasaji 1971;Seago et al. 2011). However, recent taxonomic revisions based on molecular phylogenetic study has assigned the genus to the tribe Scymnini within the subfamily Coccinellinae (Che et al. 2021). Within the genus, the subgenus Scymnus is highly diverse and can be distinguished by the following combination of characters: prosternum with distinct intercoxal carinae extending almost to the anterior edge; incomplete abdominal postcoxal line; area surrounded by postcoxal line smoother or more sparsely punctured than the basal part.
To date, 13 Scymnus species belonging to three subgenera have been reported in Korea, including four species belonging to the subgenus Scymnus: S. (S.) crinitus Fürsch, 1966; S. (S.) dorotae Bielawiski, 1980; S. (S.) frontalis (Fabricius 1787); and S. (S.) tsushimaensis Sasaji, 1970. Here, we report a new country record of S. (S.) folchiniiCanepari, 1979 from Dokdo and Ulleungdo Islands, the easternmost isolated volcanic islands of Korea. We provide diagnosis, illustrations of morphological characters, a taxonomic key to the subgenus Scymnus in Korea, and COI barcodes.
2. MATERIALS AND METHODS
Adults were collected using malaise traps and sweeping in 2022 and 2024. All specimens were preserved in 80% ethanol. Examinations of morphological characters were conducted under a stereo microscope (SMZ 645; Olympus, Tokyo, Japan). Male genitalia were dissected and placed in 10% KOH solution for several hours at room temperature before examination. Morphological photographs, except for prosternum and male genitalia, were taken using Cannon digital camera (6d mark2) with MP-E 65 mm macro lens (Canon, Inc., Tokyo, Japan). Photographs of prosternum and male genitalia were taken using a Nikon digital camera (Z7) attached to a stereoscopic microscope (BX53F; Olympus). The multiple shots were stacked using Zerene Stacker (Zerene Systems LLC, Richland, WA, USA) and edited using Photoshop (Adobe, San Jose, CA, USA). The morphological terminology used in the present study follows Pang and Gordon (1986) and Chen et al. (2013). Specimens were deposited in the following institutions: KUEM - Korea University Entomological Museum, Seoul, Republic of Korea; NIBR - National Institute of Biological Resources, Incheon, Republic of Korea.
Genomic DNA extraction, PCR, and sequencing for the COI barcode followed the protocol of Jung et al. (2016), using the primer set LCO1490 (5ʹ-GGT CAA CAA ATC ATA AAG ATA TTG G-3ʹ) and HCO2198 (5ʹ-TAA ACT TCA GGG TGA CCA AAA AAT CA-3ʹ). Molecular identification was performed by comparing the obtained sequences with those available in GenBank using the NCBI BLAST tool (available at https://blast. ncbi.nlm.nih.gov/Blast.cgi; Altschul et al. 1990) and by constructing a Maximum Likelihood (ML) tree with GenBank sequences. Maximum-likelihood (ML) analysis was conducted in RAxML v. 7.03 with the GTR+G model of evolution (Stamatakis 2006) and 1,000 bootstrap replicates. Inter- and intraspecific genetic divergences in COI barcodes were calculated as p-distances in MEGA v. 11.0.13 (Tamura et al. 2021).
3. TAXONOMIC ACCOUNTS
Family Coccinellidae Latreille, 1807
Genus ScymnusKugelann, 1794 애기무당벌레속
Subgenus ScymnusKugelann, 1794
Scymnus (Scymnus) folchiniiCanepari, 1979
참애기무당벌레 (신칭) (Fig. 2)
Scymnus (Pullus) folchiniiCanepari, 1979: 4.
Scymnus (Scymnus) hainanensis Pang et Gordon, 1986: 162.
Type locality: Beijing, China.
Diagnosis. Body length 1.96-2.17 mm and body width: 1.36-1.58 mm (n=15).
This species can be recognized by the following combination of characters: Body is oval and convex, and dorsal surface is covered with white pubescence. Head is brown, with sparse and shallow punctures. Pronotum is brown with a black triangular marking medially based at posterior margin; sometimes pronotum is entirely black except for a narrow brown area at anterior margin; pronotal punctures are coarser and sparser than those on head. Elytron is entirely black except apical dark brown margin; intermingled punctures on elytron is larger than those on pronotum. Posternal carinae (Fig. 2D) are parallel and distinct, reaching anterior margin. Postcoxal line (Fig. 2E) is incomplete and recurved forward basally, nearly extending to posterior margin of first ventrite surrounded by irregular punctures; its end extends to nearly half length of ventrite.
Male genitalia (Fig. 2F-I): Penis is stout; penis capsule has short outer process and long inner one (Fig. 2F); penis apex is simple with membranous appendage (Fig. 2F, G); penis guide (Fig. 2H, I) tip is blunt in ventral view. Parameres (Fig. 2H, I) are stout and distinctively longer than penis guide with long apical setae.
Materials examined. [NIBR] KOREA: 1♀, Gyeongsangbuk- do, Ulleung-gun, Dokdo Island (Dongdo), coastal cliff near a water treatment plant (37°14ʹ20ʺN, 131°52ʹ08ʺE), 29.V-26.VI.2024, collected by malaise trap, leg. C Lim, SH Park, and W Kim, Specimen ID: RORYIN0000006158. [KUEM] KOREA: 5♂7♀ (1♂ 2♀, DKCO001-DKCO003 used for DNA barcoding), Gyeongsangbuk-do, Ulleung-gun, Dokdo Island (Dongdo), coastal cliff near a water treatment plant (37°14ʹ 20ʺN, 131°52ʹ08ʺE), 29.V-26.VI.2024, collected by malaise trap, leg. C Lim, SH Park, and W Kim; 1♀, Gyeongsangbuk- do, Ulleung-gun, Seo-myeon, Namyang Stream (37°28ʹ51ʺN, 130°51ʹ10ʺE), 24.VI-10.IX.2024, collected by malaise trap, leg. SH Park, J Lee, and S Mok; 1♀, Gyeongsangbuk-do, Ulleung-gun, Seo-myeon, coastal cliff near Sajabawi Rock (37°32ʹ31ʺN, 130°54ʹ34ʺE), 4.VII.2022, collected by sweeping, leg. J Kim, W Lee.
Distribution. Korea (new record), China (Shanxi, Liaoning, Shandong, Henan, Zhejiang, Beijing, Anhui, Hebei, Hubei, Sichuan).
DNA barcode. Mitochondrial COI 658 bp sequences were uploaded to GenBank (accession numbers: PX111 000-PX111002). The COI barcodes sequences (658 bp) of the three S. (S.) folchinii specimens obtained in this study exhibited 99.54-99.70% similarity to a sequence from China (MK802051) and were clustered into a conspecific clade (bootstrap value=100) in the ML tree, while showing distinct genetic distances from two previously recorded species from Dokdo Island (Lee et al. 2024)-S. babai Sasaji (>15.2%) and S. ferrugatus (Moll) (>14.74%) (Fig. 3, Table 1).
Key to the species of the subgenus Scymnus in Korea
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1. Elytra with 1-2 red spots ················································· ················································ S. (S.) frontalis (Fabricius)
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- Elytra without any spots ·················································2
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2. Elytra entirely black with no dark brown apical margin ···································S. (S.) tsushimaensis Sasaji
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- Elytra black with dark brown apical margin ··············3
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3. Prosternal carinae not reaching anterior margin; end of postcoxal line extending to near anterior margin ·· ·················································· S. (S.) dorotae Bielawiski
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- Prosternal carinae reaching anterior margin; end of postcoxal line extending to near 1/2 length of ventrite ····························································································4
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4. Penis capsule with outer process nearly equal length with inner process; penis guide relatively stout; Parameres almost as long as penis guide, but slightly longer ························································ S. (S.) crinitus Fürsch
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- Penis capsule with long inner process and short outer process; Parameres distinctly longer than penis guide ··················································· S. (S.) folchinii Canepari
4. DISCUSSION
Scymnus folchinii resembles the general habitus of many Scymnus species, as noted by Chen et al. (2013). It is therefore possible that this species has been erroneously recorded as either S. (Neopullus) babai Sasaji or S. (Pullus) ferrugatus (Moll)-both of which belong to different subgenera-in previous faunistic studies of Dokdo Island (An 2008;Lee et al. 2009;Park et al. 2010;Choi et al. 2015;Lee 2016;Park and Jang 2016;Kyungpook National University Ulleungdo and Dokdo Research Institute 2018;Lee et al. 2024). Meanwhile, subgenus Scymnus is easily distinguished from subgenera Neopullus and Pullus by its incomplete abdominal postcoxal line, and S. (S.) folchinii further exhibits distinct genetic divergence from both two previously recorded species. Therefore, to determine whether the earlier records are truly erroneous, involving misidentification, it is essential to re-examine the specimens used in those previous studies.
The distribution of S. folchinii in other regions of Korea, apart from Dokdo and Ulleungdo Islands, remains unknown. This species is widely distributed in northern and eastern China, and such a broad distribution suggests that it may also be distributed on the Korean Peninsula. Our first report of S. folchinii from both Dokdo and Ulleungdo Islands also represents the first Ulleungdo Island record of the genus Scymnus. To date, two species of Scymnus have been recorded from Dokdo Island, whereas none have been reported from Ulleungdo Island, despite its considerably higher reported insect diversity (Lim et al. 2013;Lee et al. 2024) Given this limited knowledge of Scymnus species’ distribution in Korea, along with the ecological importance of their aphidophagous behaviors, our new national record from these isolated islands highlights the need for further taxonomic and faunistic studies on the genus in Korea.
