Euconnus (Euconnus) tsugaruensis Hoshina & S. Arai, 2003

Jałoszyński, Paweł, 2022, Euconnus Thomson of Japan: redescriptions of species established by Reitter, Sharp and Franz, new synonyms, and summary of current state of knowledge (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5093 (1), pp. 1-37 : 29-31

Euconnus (Euconnus) tsugaruensis Hoshina & S. Arai

Euconnus (Pycnophus) tsugaruensis Hoshina & Arai in Hoshina et al. (2003): 28.

Euconnus tugaruensis ; misspelling in Hoshina & Arai 2003: 11.

Euconnus (Euconnus) tsugaruensis Hoshina & S. Arai ; Jałoszyński, 2021b: 268, implied, by placing Pycnophus as junior synonym of Euconnus s. str.

Euconnus (Euconnus) hosakae Hoshina et al., 2020: 72 ; syn. n.

( Figs 79–83 )

Material examined. HONSHU: Fukushima Pref.: 1 ♂, 2 ♀♀, Ten-ei-mura, Futamata Valley , 850 m, 19.10.2003 , P. Jałoszyński (cPJ); 1 ex. Minamiaizu, Kamabusayama Mt. , Asahida V., 16.07.1949, K. Nagayama leg. ( NSMT) ;

Gunma Pref.: 1 ex., Kumanotaira, Usui Pass, Matsuida T., 17.06.1995, S. Nomura leg. ( NSMT) ; Ibaraki Pref.: 1 ex., Nishi-Kanasago Shr., Kanasago-mura, 04.06.1994, S. Ohmomo leg. ( NSMT) .

Remarks. This species is known to occur on Honshu. Hoshina et al. (2003) described E. tsugaruensis based on a single male and two females. The body length of the male was given as 1.7 mm; the aedeagus was illustrated in a resting position, not distorted, which makes it possible to identify this species. The only enigmatic part of the description is “metasternum (...) with a high median carina; mesosternum smooth and convex”, which is repeated without any changes also for E. otorii a few pages further on. It is possible that the authors confused mesoventrite with metaventrite. Several years later, Hoshina et al. (2020) described the very same species again, under the name of E. hosakae . Interestingly, they compared the newly described species to E. ohnoensis , whose aedeagus is not very similar to that illustrated for E. hosakae , but did not make any remarks concerning the similarity to E. tsugaruensis . The type series of E. hosakae included two males and one female, and the body length is given as 1.51–1.58 mm. I examined six specimens that match descriptions of both E. tsugaruensis and E. hosakae , and their body lengths range from 1.53 to 1.60 mm; a range 1.51–1.70 is not unusual within one Euconnus species. The aedeagi illustrated for E. tsugaruensis and E. hosakae are identical; differences are results of unskillful drawing, as already demonstrated e.g., for E. dulcis redescribed by Hoshina (2019c); see remarks at the latter species in earlier section of this paper. Although the general shape of the median lobe illustrated for E. tsugaruensis and E. hosakae are slightly different, the aedeagus illustrated in the present paper ( Figs 80–83 ) demonstrates that the endophallic structures in all examples are exactly the same, only simplified in a different way in Hoshina et al. (2003) and Hoshina et al. (2020). Without doubt, E. tsugaruensis and E. hosakae are identical.

Apart from the unique aedeagus, E. tsugaruensis can be easily distinguished from remaining nominal Euconnus species known to occur in Japan by the conspicuous body form ( Fig.79 ), slender antennae almost gradually thickening toward apices, the remarkable shape of the head, which has particularly long and slightly concave tempora and narrow vertex, and the setal pattern (nearly asetose head, pronotum with dense setae and bristles, and elytra with sparse, long, erect setae).

The placement of E. tsugaruensis in the subgenus Pycnophus Casey, 1897 (currently a junior synonym of Euconnus s. str.), and E. hosakae in Euconnus s. str., is here confirmed as correct.

Figures

FIGURES 79–83. Euconnus tsugaruensis, male from Fukushima Pref. Dorsal habitus (79); aedeagus in ventral (80, 82) and lateral (81, 83) views.