Clidicostigus arachnipes Jałoszyński, Brunke & Bai, 2017

Cao, Hai-Jing, Liu, Yu-Wei & Liu, Hao-Yu, 2025, Taxonomic notes on † Clidicostigus arachnipes Jałoszyński, Brunke & Bai, 2017, a predominant ant-like stone beetle in the mid-Cretaceous Burmese amber, Zootaxa 5621 (4), pp. 493-500 : 495-499

publication ID	https://doi.org/10.11646/zootaxa.5621.4.8
publication LSID	lsid:zoobank.org:pub:CBC92360-74C6-476E-9533-CA1008DF4DC2
DOI	https://doi.org/10.5281/zenodo.15263210
persistent identifier	https://treatment.plazi.org/id/03C3A313-FF91-9C3B-9284-FDAF32D454A6
treatment provided by	Plazi
scientific name	Clidicostigus arachnipes Jałoszyński, Brunke & Bai, 2017
status

Treatment

Clidicostigus arachnipes Jałoszyński, Brunke & Bai, 2017 View in CoL

( Figs 1‒6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 , Table 1 View TABLE 1 )

Clidicostigus arachnipes Jałoszyński, Brunke & Bai, 2017: 112 View in CoL , fig. 2A‒B; Jałoszyński, 2018: 109, fig. 163; Jałoszyński et al., 2018: 19, fig. 1E; Ross, 2024: 36.

Cascomastigus monstrabilis Yin & Cai, 2017: 2 View in CoL , fig. 1a‒d. Synonymized by Yin & Zhuo, 2019: 241.

Examined material. Thirteen specimens ( MHBU, No. BU-COL-SCY001-013) in thirteen pieces of Myanmar ambers; deposited in MHBU .

Descriptive notes. Body length 5.40–7.50 mm ( Table 1 View TABLE 1 ), black ( Fig. 1 View FIGURE 1 ; Yin et al., 2017) or dark brown ( Fig. 2 View FIGURE 2 ; Jałoszyński et al., 2017: fig. 2A). Head length 0.60–1.20 mm ( Table 1 View TABLE 1 ). Labial palpus ( Fig. 1C View FIGURE 1 ) moderately long, composed of elongate palpomere I, rod-shaped II, which is asymmetrical and broader than I, III narrowly subulate. Maxillary palpomere IV ( Figs 1B View FIGURE 1 , 2B View FIGURE 2 , 3B View FIGURE 3 , 4B View FIGURE 4 , 5B View FIGURE 5 ) with enlarged apical part strongly bent basally. Antenna 4.19– 6.70 mm in length ( Table 1 View TABLE 1 ), pedicel nearly 0.6–1.38 times as long as scape, antennomere IV about 1.3–2.2 times as long as III, V about 1.2–1.7 times as long as IV, VIII nearly as long as or feebly longer than IX ( Figs 1A View FIGURE 1 , 2B View FIGURE 2 , 3B View FIGURE 3 , 4B View FIGURE 4 , 5B View FIGURE 5 ). Pronotum 1.2–1.84 mm in length, nearly twice as long as wide ( Figs 1A View FIGURE 1 , 2A View FIGURE 2 , 3A View FIGURE 3 ). Each elytron ( Figs 1A View FIGURE 1 , 2A View FIGURE 2 , 4A View FIGURE 4 ) with six striae. Protibia ( Fig. 1B View FIGURE 1 ) with a subapical emargination.

Remarks. In the original description of this species ( Jałoszyński et al. 2017), the elytron was described with four striae. Here the available specimen clearly shows that each elytron of this species has six striate ( Figs 1A View FIGURE 1 , 3A View FIGURE 3 , 5A View FIGURE 5 ), as described by Yin et al. (2017).

Among our available materials, one specimen ( MHBU, No. BU-COL-SCY006) seems different in the shape of pronotum, which is about 1.2 times as wide as long ( Fig. 6A View FIGURE 6 ). However, it is of a poor quality because of a high degree of carbonization and deformation. But it can be treated as this species on the basis of the large body size (6.2 mm in length), elongate maxillary palpomere IV ( Fig. 6B View FIGURE 6 ), and antennomere III evidently shorter than IV ( Fig. 6A View FIGURE 6 ). In C. minor ( Yin et al. 2018) , the body is smaller (4.0 mm in length), maxillary palpomere IV rather stout, narrowed at base and rounded at apex, and antennomeres III and IV subequal in length.

Discussion. Although dozens of ambers are obtained in the present study, we have not found any additional species of the genus Clidicostigus at the moment. Instead, we consider that C. arachnipes is a highly variable species, exhibiting significant variations in body size, antennal length, and the relative lengths of antennomeres. As indicated in Table 1 View TABLE 1 , body length, which may vary considerably due to different preservation states and observation angles, can serve as a useful criterion for species identification, given that C. arachnipes is consistently larger (longer than 5.4 mm) than C. minor (approximately 4.0 mm). Accordingly, individuals with larger body sizes tend to possess longer antennae and antennomeres.

Despite the variations observed in the available specimens of C. arachnipes , it should be kept in mind that at least a part of the variability can be attributed to a very poor preservation, distortion, and measurements carried out at various angles (an issue that reflects methodological error), as highlighted by Yin et al. (2020). Consequently, caution and meticulous comparisons are essential when establishing additional new taxa. Any further new species of Clidicostigus should be based solely on the stable and unique combination of male features, such as body size and the shape of maxillary palpomeres, among others.

V	Royal British Columbia Museum - Herbarium

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No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.

Taxonomy

Kingdom	Animalia
Phylum	Arthropoda
Class	Insecta
Order	Coleoptera
Family	Staphylinidae
SubFamily	Scydmaeninae
SuperTribe	Mastigitae
Tribe	Mastigini
Genus	Clidicostigus