Caenoscelis koreanus Shin, Park, Lee, and Park, 2023

Shin, Joong-In, Park, Sun-Jae, Lee, Seung-Gyu & Park, Jong-Seok, 2023, Taxonomic Review of the Genus Caenoscelis C. G. Thomson (Coleoptera: Cryptophagidae: Cryptophaginae) in Korea with Description of a New Species, The Coleopterists Bulletin 77 (3), pp. 469-476 : 472-475

Caenoscelis koreanus Shin, Park, Lee, and Park , new species zoobank.org/ urn:lsid:zoobank.org:act:7505F55C-81B8-4946-B957-8C7440846208 ( Figs. 1A , 2A , 3A , 5A )

Material EXamined (n = 2, 2♂♂). Holotype. 1♂ (card mounted, genitalia and abdomen dissected and mounted on plastic card, NIBR),

“ HOLOTYPE / CBNUIC ” [red label, printed]; “ Korea: Chungbuk Prov. / Gaesin-dong, Heungdeok-gu,/ Cheongju-si , 24.XI.2020,/ 36°37′43.5′′N 127°27′ 16.7′′E, 75 m,/ sifting soil & leaf litter, J.-I. Shin ” [white label, printed]; Paratype. 1♂ (slide mounted, CBNUIC), Korea: Jeju Prov. Donmullae-gil, Aewoleup, Jeju-si, 12.I.2022, 33°23′55′′N 126°19′33′′E, 186 m, sifting soil & leaf litter, J.-W. Kang, J.-W. Seo, J.-W. Kim .

Diagnosis. Adult males of this species can be distinguished from other Caenoscelis species by the following combination of characters: antennomere X subquadrate, distinctly wider than IX, dense setae present apically ( Fig. 2A , arrow); antennomere XI slightly longer than X ( Fig. 2A ); pronotum about 1.15–1.20 times as wide as long ( Fig. 3A ); hind wings well developed; parameres subacute, densely punctured, with pair of long apical setae present, bearing three pairs of short setae laterally ( Fig. 5A ); lateral lobes indistinctly separated, pointed apically ( Fig. 5A ), pair of internal sclerites pointed apically ( Fig. 5A , arrow).

Description of Adult Male. Length 1.94–2.04 mm. Body long and narrow, 2.64–2.67 times as long as wide, highly convex, moderately shining, color yellowish brown, antennomeres X–XI, palps, and legs slightly brighter than body ( Fig. 1A ). Dorsal pubescence suberect, length of seta about 0.05–0.09 mm.

Head. Head 1.78–1.80 times as wide as long, densely punctured; diameter of dorsal puncture about 0.011 –0.013 mm, dorsal punctures separated by 0.4–0.8 diameter; eye length about 0.12–0.13 mm, slightly prominent, diameter of facet about 0.014 –0.016 mm; antenna slender, length about 0.88–0.93 mm, antennomere X reaching pronotal base ( Fig. 1A ); antennomere I 1.5 times as long as wide ( Fig. 2A ); antennomere II symmetrical, 1.3 times as long as wide, 0.6–0.7 times shorter than I ( Fig. 2A ); antennomere III symmetrical, slightly shorter and narrower than II ( Fig. 2A ); antennomeres IV–VIII as long as wide, VI and VIII slightly smaller than others ( Fig. 2A ); antennomere VII markedly asymmetrical, inner margin much more convex than outer margin ( Fig. 2A ); antennomere IX 1.7–1.8 times as wide as long ( Fig. 2A ); antennomere X 1.2 times as wide as long, 1.4–1.5 times wider than IX ( Fig. 2A , arrow); antennomere XI as long as wide, 1.1 times longer than X, about 0.85 times narrower than X ( Fig. 2A ).

Thorax. Pronotum 1.17–1.19 times as wide as long, widest slightly behind middle, lateral margin uniformly curved anteriorly and posteriorly, sparsely punctured ( Fig. 3A ); diameter of puncture about 0.014 –0.017 mm, punctures separated by 1.1–1.5 diameter; sublateral lines distinct and complete, moderately separated from lateral margin, divergent from lateral carinae at basal two-thirds ( Fig. 3A ); basal groove shallow and transverse ( Fig. 3A ). Prosternum densely punctured; diameter of puncture about 0.012 –0.017 mm, punctures separated by 0.5–0.9 diameter. Metaventrite sparsely punctured; diameter of puncture about 0.010 –0.015 mm, punctures separated by 1.0–1.5 diameter.

Elytra. Elytra together 1.91–1.93 times as long as wide, 2.72–2.77 times longer than pronotum, sides weakly arcuate and widest at basal one-third, sparsely punctured ( Fig. 1A ); diameter of puncture about 0.013 –0.016 mm, punctures separated by more than 1.5 diameter.

Abdomen. Abdominal ventrite 1 densely punctured, diameter of puncture about 0.011 –0.015 mm, punctures separated by 0.7–1.1 diameter; abdominal ventrites 2–4 sparsely punctured, diameter of puncture less than 0.010 mm, punctures separated by more than 1.5 diameter; abdominal ventrite 5 densely punctured, diameter of puncture about 0.010 –0.012 mm, punctures separated by 0.4–0.8 diameter.

Aedeagus. Parameres entirely fused to each other, not articulated to phallobase, extended dorsally and conical in shape ( Fig. 5A ); dorsal membrane reaching apex of distipenis, ventral membrane and phallobase reaching middle of distipenis ( Fig. 5A ); internal apodeme distinct ( Fig. 5A ); combined parameres slightly longer than wide, outer margin weakly concave ( Fig. 5A ); apical setae length about 0.060 –0.070 mm, three pairs of short setae at least 2.0 times shorter than apical setae ( Fig. 5A ); distipenis 1.7 times as long as wide, not punctured, nearly parallel sided from base to middle, undulately narrowed from middle to apex ( Fig. 5A ); basipenis 3.5 times as long as wide, 2.4 times longer than distipenis.

Female unknown.

Distribution. Korea: Chungbuk Prov., Jeju Prov. ( Fig. 6 ).

Habitat. This species was collected from late autumn to winter by sifting soil and leaf litter in mixed forests.

Etymology. This species is named after the type locality, Korea.

Caenoscelis ferruginea (C. R. Sahlberg, 1820) ( Figs. 1B , 2B , 3B , 4A , 5B )

Cryptophagus ferrugineus C. R. Sahlberg 1820: 58 .

Atomaria pallida Wollaston 1846: 452 .

Atomaria testacea Zimmermann in LeConte 1869: 258.

Caenoscelis brisoutii Seidlitz 1888: 256 .

Caenoscelis ochreosa Casey 1900: 105 .

Material EXamined (n = 2, 1♂ 1♀). 1♂ (card mounted, antennae, genitalia, and abdomen dissected, NIBR) , Korea: Gangwon Prov. Mt. Odae, Dongsan-ri, Jinbu-myeon , Pyeongchang-gun , 30. VIII –25.IX.2012, F.I. T, S.-J. Park, I.-J. Heo ; 1♀ (slide mounted, CBNUIC) , Korea: Gangwon Prov. Sukam-ri, Bukpyeong-myeon, Jeongseon-gun , 15. XII.2019, 37°29′33.7′′N 128°45′53.7′′E, 296 m, sifting leaf litter & dead wood debris, C. E. Carlton, J.-S. Park, M.-S. Jang, Y.-J. Choi, J.-Y. Kang, J.-W. Kang, U.-J. Byeon, T.-Y. Jang, J.-W. Kim .

Diagnosis. Adult males of this species can be distinguished from other Palearctic Caenoscelis species by the following combination of characters: head sparsely punctured, dorsal punctures separated by more than their diameter ( Fig. 4A ); antennomere I about 1.5 times as long as wide, clearly shorter than 2.0 times as long as wide ( Fig. 2B ); antennomere II symmetrical ( Fig. 2B ); antennomere X transverse, slightly wider than IX ( Fig. 2B ); hind wings well developed; parameres triangular, not elongate, evenly punctured, long apical setae absent ( Fig. 5B ); lateral lobes hook-shaped, moderately punctured ( Fig. 5B ).

Redescription. Length 2.12–2.23 mm. Body long and wide, 2.44–2.50 times as long as wide, moderately convex, color reddish brown, antennomeres X–XI, palps, and legs slightly brighter than body ( Fig. 1B ). Dorsal pubescence suberect, length of seta about 0.04–0.09 mm.

Head. Head 1.76–1.82 times as wide as long, diameter of dorsal puncture about 0.009 –0.012 mm, punctures separated by 1.5–2.0 diameter ( Fig. 4A ); eye length about 0.11–0.12 mm, moderately prominent, diameter of facet about 0.014 –0.016 mm; antenna robust, length about 0.91–0.95 mm, reaching pronotal base ( Fig. 1B ); antennomere II 1.2 times as long as wide, 0.7 times shorter than I ( Fig. 2B ); antennomere III 1.3 times as long as wide ( Fig. 2B ); antennomeres V–VIII as long as wide, V and VII slightly larger than others ( Fig. 2B ); antennomere IX 1.3 times wider than VIII ( Fig. 2B ); antennomere X 1.3–1.4 times as wide as long, 1.1–1.2 times wider than IX ( Fig. 2B ); antennomere XI longer than wide, longer than X and slightly narrower than X ( Fig. 2B ).

Thorax. Pronotum 1.28–1.35 times as wide as long, widest slightly behind middle, anterior lateral margin more strongly curved than posterior, densely punctured ( Fig. 3B ); diameter of puncture about 0.017 –0.021 mm, punctures separated by 0.4–0.8 diameter; sublateral lines distinct and complete, slightly separated from lateral margin, divergent from lateral carinae at basal two-thirds ( Fig. 3B ); basal groove shallow and transverse ( Fig. 3B ). Prosternum densely punctured; diameter of puncture about 0.016 –0.019 mm, punctures separated by 0.4–0.8 diameter. Metaventrite densely punctured; diameter of puncture about 0.015 –0.018 mm, punctures separated by 0.3–0.7 diameter.

Elytra. Elytra together 1.48–1.61 times as long as wide, 2.45–2.60 times longer than pronotum, sides moderately arcuate and widest at basal one-third, sparsely punctured ( Fig. 1B ); diameter of puncture about 0.011 –0.014 mm, punctures separated by more than 1.5 diameter.

Abdomen. Abdominal ventrites 1–4 densely punctured, diameter of puncture about 0.010 –0.016 mm, punctures separated by 0.5–1.0 diameter; abdominal ventrite 5 sparsely punctured, diameter of puncture less than 0.010 mm, punctures separated by more than 1.5 diameter.

Aedeagus. Parameres fused to each other, but inner border distinct, articulated to phallobase ( Fig. 5B ); internal apodeme indistinct ( Fig. 5B ); combined parameres 1.7 times as wide as long, outer margin slightly arcuate, apical seta length about 0.015 –0.020 mm ( Fig. 5B ); distipenis 1.3 times as long as wide, nearly parallel sided, internal sclerite arcuate apically, forked basally ( Fig. 5B ); basipenis 3.3 times as long as wide, 2.9 times longer than distipenis.

Distribution. Nearctic Region; Europe; Eastern Siberia, Russian Far East, Korea: Gangwon Prov. ( Fig. 6 ).

Habitat. This species was collected by sifting leaf litter and dead wood debris in mixed forests.

Caenoscelis sibirica Reitter, 1889 ( Figs. 1C , 2C , 3C , 4B , 5C )

Caenoscelis sibirica Reitter 1889: 309 . Caenoscelis fleischeri Reitter 1889: 309 . Caenoscelis grandis C. G. Thomson 1892: 1773 .

Material EXamined (n = 11, 6♂♂ 5♀♀). 2♂♂ 2♀♀ (2♂♂ card mounted, genitalia and abdomen dissected and mounted on plastic card, 2♀♀ point mounted, CBNUIC) , Korea: Gyeonggi Prov. Yongchu-ro, Gapyeong-eup, Gapyeong-gun , 15.IV.2019, 37°51′29.5′′N 127°28′01.0′′E, 193 m, sifting moss & leaf litter near stream, J.-S. Park, J.-W. Kang, J.-Y. Kang, Y.-J. Choi ; 1♂ (card mounted, genitalia and abdomen dissected and mounted on plastic card, CBNUIC), Korea: Chungbuk Prov. 302-52, Mongnyeon-ro, Sangdang-gu, Cheongju-si , 09.IV.2021, 36°36′30.8′′N 127°32′15.8′′E, 177 m, sifting soil & leaf litter, J.-W. Seo ; 1♂ (card mounted, genitalia and abdomen dissected and mounted on plastic card, CBNUIC), Korea: Chungbuk Prov. Gaesin-dong, Heungdeok-gu, Cheongju-si , 13.X.2022, 36°37′36.3′′N 127°27′22.2′′E, 70 m, sifting soil & leaf litter, J.-I. Shin ; 2♂♂ 3♀♀ (1♂ card mounted, genitalia and abdomen dissected and mounted on plastic card, 1♂ slide mounted, 3♀♀ point mounted, CBNUIC) , Korea: Gangwon Prov. Yongdae-ri, Buk-myeon, Inje-gun , 13. V.2021, 38°14′26.3′′N 128°23′51.2′′E, 552 m, J.-S. Oh .

Diagnosis. Adult males of this species can be distinguished from other Palearctic Caenoscelis species by the following combination of characters: head densely punctured, dorsal punctures separated by less than their diameter ( Fig. 4B ); antennomere I about 1.5 times as long as wide, clearly shorter than 2.0 times as long as wide ( Fig. 2C ); antennomere II symmetrical ( Fig. 2C ); antennomere X transverse, slightly wider than IX ( Fig. 2C ); hind wings well developed; parameres trapezoidal, not elongate, distally punctured, pair of long apical setae present ( Fig. 5C ); lateral lobes folded near apex, scarcely punctured ( Fig. 5C ).

Distribution. Europe; Japan, Mongolia, Russian Far East, Korea: Chungbuk Prov., Gyeonggi Prov., Gangwon Prov. ( Fig. 6 ).

Comments. This species was first recorded in North Korea by Lyubarsky (1991). The description and illustrations of detailed characters of this species were provided in Otero (2013: 37–39).

Habitat. This species was collected by sifting soil, leaf litter, and moss in mixed forests.

Figures

Fig. 1. Male habitus, dorsal. A) Caenoscelis koreanus, new species, B) C. ferruginea, C) C. sibirica. Scale bars = 1.0 mm.

Fig. 2. Male left antenna, dorsal. A) Caenoscelis koreanus, new species, B) C. ferruginea, C) C. sibirica. Arrow, antennomere X. Scale bars = 0.5 mm.

Fig. 3. Pronotum, dorsal.A) Caenoscelis koreanus, new species, B) C. ferruginea, C) C. sibirica. Scale bars = 0.5 mm.

Fig. 5. Distipenis and parameres, dorsal. A) Caenoscelis koreanus, new species, B) C. ferruginea, C) C. sibirica. AS, apical seta; IA, internal apodeme; IB, inner border; LL, lateral lobe; PA, paramere. Arrow, internal sclerites. Scale bars = 0.2 mm.

Fig. 6. Collection localities in Korea. Triangle, Caenoscelis koreanus, new species; square, C. sibirica; circle, C. ferruginea.

Fig. 4. Head, dorsal. A) Caenoscelis ferruginea, B) C. sibirica. Scale bars = 0.2 mm.