Caenoscelis ferruginea (C. R. Sahlberg, 1820 )

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 : 474

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.

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