The genus HoloparamecusCurtis, 1833 has historically been recorded either as a genus within Merophysiinae Seidlitz, 1872 of Endomychidae Leach, 1815 (Tomaszewska, 2000;Rücker and Löbl, 2007;Shockley et al., 2009;Robertson et al., 2015;Arriaga-Varela et al., 2021, 2023) or treated as a genus within the subfamily Holoparamecinae Seidlitz, 1888 of Merophysiidae (Rücker, 2018, 2020;Reiker et al., 2020). In this paper, we will follow the classification system of the Check List of Insects from Korea, which classifies it as a genus within Merophysiinae of Endomychidae (Park and Lee, 2021).
The genus Holoparamecus comprises 57 species worldwide, including two extinct species (Rücker, 2020). Rücker (2018) has divided this genus into seven subgenera. Also, two extinct species of the subgenus Bluenus Belon were recently recorded by Reiker et al. (2020). The genus Holoparamecus is currently classified into the following seven subgenera: Holoparamecus s. str.; BlumenusBelon, 1887;CalyptobiumAubé, 1843;MicroparamecusDajoz, 1967;NeoparamecusDajoz 1974; Tocalium Motschulsky, 1867; and TomyriumReitter, 1881 (Rücker, 2018, 2020;Reiker et al., 2020). In the Eastern Palearctic, eight species from two subgenera have been recorded (Shockley et al., 2009;Rücker, 2020, Table 1). In Korea, only H. (s. str.) singularis (Beck, 1817) was recorded (Shockley et al., 2009).
In this study, we record two species, H. (s. str.) ragusae and H. (Calyptobium) contractus, for the first time in Korea. Additionally, we provide habitus photos, a distribution map, and an identification key to these two species.
Material and Methods
A total of six specimens were examined. All specimens were prepared as dried specimens. Observation was conducted using a Leica S8APO. Images were obtained using a Sony ILCE-7RM3 mirrorless camera with a Mitutoyo M Plan Apo 20X objective lens. Genitalia were observed after being dissolved with Proteinase K provided by a DNeasy Blood & Tissue Kit. Genitalia were stored in glycerol in 0.2 ml tubes as specimens. Obtained photographs were stacked using Helicon Focus 8. The length of each specimen stated in the text was measured based on the maximum length. The distribution map was created using SimpleMappr (Shorthouse, 2010). All photographs were edited using Adobe Photoshop 2024.
All specimens examined in this study were deposited in the following collections and indicated parenthetically: CBNUIC Chungbuk National University Insect Collection, Cheongju, South Korea
Taxonomic Accounts
Family Endomychidae Leach, 1815 무당벌레붙이과
Subfamily Merophysiinae Seidlitz, 1872 두줄가슴무당벌레 붙이아과
Genus HoloparamecusCurtis, 1833 두줄가슴무당벌레붙이속 HoloparamecusCurtis, 1833. [Type species: Holoparamecus depressusCurtis, 1833: 186]
Description. Body size 0.50-1.80 mm; small, slender; body color mostly yellow to red, sometimes yellowish-black to black; antennae with 9-11 segments, apical one or two segments clubed; pronotum with various length of folds extending from base on each side, with narrow transverse impression or two raised humps between folds, impression or humps connected or separated by short median ridge; prosternum with open coxal cavity at procoxae base; tarsal fomular 3-3-3; almost species with well-developed eyes; elytra oval-shaped, fine irregular puncture, shallow to deep sutural stria. For detailed description of the genus, refer to Rücker (2020).
Distribution. Worldwide (except for polar region)
Key to subgenera and species of the genus Holoparamecus in Korea
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1 Antennae with 9 segments in male, 10 segments in female (Fig. 1) [subgenus Holoparamecus s. str.] ···················· 2
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- Antennae with 11 segments in both sexes (Fig. 2) [subgenus CalyptobiumAubé, 1843] ····································· ························· H. (Calyptobium) contractus Wollaston
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2(1) Male antennomeres 4-6 distinctly longer than wide, 8 inverted trapezoidal; pronotum without furrow at middle; aedeagus (Figs. 1, 3A-C) ······························ ··········································H. (s. str.) ragusae Reitter
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- Male antennomeres 4-6 as long as wide, 8 slightly oval; pronotum with faint furrow at middle; aedeagus (Rücker, 2020, figs. 1339, 1354, 1356, 1357) ······························· ············································H. (s. str.) singularis (Beck)
Subgenus HoloparamecusCurtis, 1833
Holoparamecus (s. str.) ragusaeReitter, 1875 붉은두줄가슴 무당벌레붙이(신칭)(Figs. 1, 3-4)
Holoparamecus ragusae: Reitter, 1875: 309.
Diagnosis. Male of this species can be distinguished from other members of Holoparamecus by the following combination characters: antennomere 10 gradually widened to apex, distinctly longer than 11; pronotum broad, shallow impression on pronotal base, with folds on each side of impression, folds extending as long as pronotum length half (Fig. 1); aedeagus elongated, apex rounded and curved laterally in ventral view, with capsule, capsule with several setae at apex (Figs. 3A-C).
Male redescription. Body size 1.55-1.60 mm; head, pronotum, and elytra reddish-brown, legs, antennae slightly lighter than body.
Head. Head narrower than pronotum, wider than long; eyes as long as half length of head; antennae with 9 segments, antennomere 1 not fully visible in dorsal view, 2-5 elongate and subrectangular, 6-7 slightly longer than wide, subquadrate, 8 gradually widening to apex, inverted trapezoidal, 9 smaller than 8.
Thorax. Pronotum narrower than elytra (0.47 : 0.70), wider than long (0.39 : 0.47), gradually widening from apex to apical 1/3, widest at apical 1/3, gradually narrowing from apical 1/3 to base, densely covered with punture, puntation small and transverse, shallow impression on base, with folds on each side of impression, folds extending as long as half length of pronotum. Prosternum with shallow punctures on middle, procoxal cavity separated by prosternal process. Mesoventrite short, gradually widening, with lines extending from each side of mesocoxal cavity; mesocoxal cavity sperated by meso-, metaventrite. Metaventrite longer than mesoventrite, gradually widening, sparesely covered with shrot setae.
Elytra. Elytra distinct longer than wide (1.03 : 0.70), oval, sparsely covered with small longitudinal puncture, with shallow suture line.
Abdomen. Ventrites slightly longer than sum of meso- and metaventrite, gradually narrowing to distally, with fine pubescence, ventrite 1 longest, 2-4 similar length, 5 slightly longer than 2-4.
Wings. Hind wings distinctly shorter than elytra.
Genitalia. Aedeagus elongated, apical margin rounded and curved laterally in ventral view, slightly ‘S’ shpaed in lateral view, with capsule, capsule with several setae at apex.
Material examined. 2♂♂1♀, Bokgyosinchon-gil 10-11, Daeya-myeon, Gunsan-si, Jeonbuk Prov., Korea (35°54'54.6"N 126°50'16.6"E, 7 m) 3.VIII.2021, sifting soil & reed litter, J.-W. Kang, J.-W. Kim, preserved in CBNUIC
Habitat. This species was collected by sifting soil and reeds.
Distribution. Palearctic: South Korea (new record; Fig. 4), Japan, Belgium, Czech Republic, France, Hungary, Italy, Netherlands, Switzerland; Nearctic: Mexico, Canada, United States; Neotropic: Chile; Cosmopolitan (Shockley et al., 2009;Rücker, 2020).
Holoparamecus (s. str.) singularis (Beck, 1817) 두줄가슴무 당벌레붙이
Silvanus singularisBeck, 1817: 14.
Holoparamecus azoricusMequignon, 1942: 10.
Holoparamecus populiMotschulsky, 1867: 100.
Holoparamecus populiMotschulsky, 1867: 99.
Holoparamecus obtususReitter, 1884: 63.
Calyptobium villaeAubé, 1843: 243
Korean records.Holoparamecus singularis: Shockley et al., 2009: 68; Hong and Lee, 2014: 187; Jeong, 2020: 18.
Distribution. Palearctic: Algeria, Azores, Belgium, Canary Islands, China, Cyprus, Egypt, France, Great Britain, Greece, Israel, Italy, Lebanon, Libya, Madeira, Morocco, Netherlands, South Korea, Spain, Switzerland, Tunisia, Turkey; Nearctic: Canada, Mexico, United States; Oriental: India; Cosmopolitan (Shockley et al., 2009;Rücker, 2020).
Comments. According to Shockley et al. (2009), the distribution of this species includes South Korea. However, Jeong (2020) indicates that this species has not been recorded in neighboring countries of the Korean Peninsula such as Japan, China, and Far East Russia. Furthermore, this species was not found in a huge number of beetle specimens collected by our lab from 2018 to 2024. Given these circumstances, a detailed survey into the distribution of this species on the Korean Peninsula is needed.
Subgenus CalyptobiumAubé, 1843
CalyptobiumAubé, 1843: 242. [Type species: Calyptobium caularum Aubé, 1843: 242]
Holoparamecus (Calyptobium) contractusWollaston, 1874 좁은두줄가슴무당벌레붙이(신칭)(Figs. 2-4)
Holoparamecus contractus: Wollaston, 1874: 203.
Diagnosis. Male of species can be distinguished from other members of Holoparamecus by the following combination characters: Head densely covered with irregular transverse puncture; antennomere 10 gradually widening to apically inverted triangular, 11 slightly wider than 10; pronotum abruptly narrowing at base 1/3, sparsely covered with short pubescence, small puncture, with transverse humps on base, humps separated by short median ridge, with lateral carinae on base, lateral carinae as long as 1/3 pronotum (Fig. 2); aedeagus elongated, broad, curved ventrally in lateral view, apical margin slightly rounded, internal structure complex; tegmen gradually narrowing apically, apex with four long setae and two short setae (Figs. 3D-E).
Male redescription. Body size 1.49 mm; head darkishbrown, pronotum, and elytra yellowish-brown, legs, antennae slightly lighter than pronotum and elytra.
Head. Head narrower than pronotum (0.34 : 0.42), wider than long, densely covered with irregular transverse puntures; eyes large, as long as half length of visible head in dorsal view; antennae with 11 segments, antennomere 1 not fully visible in dorsal view, 2-5 elongate and subrectangular, 6-9 as long as wide, subquadrate, 10 gradually widening apically, inverted triangular, 11 slightly wider than 10; fronto-clypeal suture somewhat arcuate.
Thorax. Pronotum narrower than elytra (0.42 : 0.58), wider than long (0.36 : 0.42), gradually widening from apex to apical 1/3, widest at apical 1/3, abruptly narrowing to apical 2/3, slightly parallel apical 2/3 to base, sparsely covered with short pubescence, small punctures, with transverse humps on base, humps separated by short median carina, with lateral carinae on base, lateral carinae as long as 1/3 length of pronotum. Prosternum with lateral line, lateral line elongated apex to base, procoxal cavity separated by prosternal process. Mesoventrite short, gradually widening. Metaventrite longer than mesoventrite, gradually widening, sparsely covered with short pubescences.
Elytra. Elytra distinctly longer than wide (0.94 : 0.58), oval, sparsely covered with fine short pubescences, with suture stria.
Abdomen. Ventrites slightly longer than sum of meso- and metaventrite, gradually narrowing to distally, with fine pubescence, ventrite 1 longest, 2-4 similar length, 5 slightly longer than 2-4, gradually narrowing to distally.
Legs. Moderately long and slender; femur as long as tibia; tarsomere 1 moderately long, 2 short, 3 longest; meso-, metatrochanter subrectangular.
Wings. Hind wings slightly shorter than elytra.
Genitalia. Aedeagus elongated, broad, curved ventrally in lateral view, apical margin slightly rounded, internal structure complex; tegmen gradually narrowing to apex, apex with four long setae and two short setae.
Material examined. 2♂♂1♀, Josan-ro 221, Sora-myeon, Yeosu-si, Jeonnam Prov., Korea (34°46'42.8"N 127°37'22.8"E, 51.6 m) 22.VI.2022, , sifting soil & herbal debris, T.-Y. Jang, S.-H. Yu, preserved in CBNUIC
Habitat. This species was collected by sifting soil and herbasl debris.
Distribution. Palearctic: South Korea (new record; Fig. 4), Japan (Shockley et al., 2009).