Oxytelus (Tanycraerus) jessoensis Bernhauer, 1907

Gildenkov, Mikhail Yu. & Semionenkov, Oleg I., 2024, Little known species of the Genus Oxytelus (Coleoptera, Staphylinidae) from Kamchatka, Amurian Zoological Journal XVI (1), pp. 184-189 : 185-188

Oxytelus (Tanycraerus) jessoensis Bernhauer, 1907

Material. 2♂, 6 exs. ‘ Russia: Kamchatka, Bystrinsky Natural Park. Floodplain of the Kozyrevka River ( Populus , fern, horsetail), 21.08.2015, leg. V. I. Lobanova’ ‘ Oxytelus assingi Schülke, 2012 V. B. Semenov det. 2015’ ‘ Oxytelus jessoensis Bernhauer, 1907 , det. M. Gildenkov, 2021’ (cMG); 1♂, 1♀ ‘ Russia: Kamchatka, Bystrinsky Natural Park. Floodplain of Belaya River, near the stream ( Alnus , Salix ), 07.2015, leg. V. I. Lobanova’ ‘ Oxytelus jessoensis Bernhauer, 1907 , det. O. Semionenkov, 2021’ (cOS); 1♂, 3 exs. ‘ Russia: Kamchatka, Bystrinsky Natural Park. Floodplain of the Kozyrevka River ( Alnus , Salix ), 21.08.2015, leg. V. I. Lobanova’ ‘ Oxytelus jessoensis Bernhauer, 1907 , det. M. Gildenkov, 2021’ (cMG); 5 exs. ‘ Russia: Kamchatka, Bystrinsky Natural Park. Floodplain of the Kozyrevka River, hilltop ( Picea , Betula ), 07.2015, leg. V. I. Lobanova’ ‘ Oxytelus assingi Schülke, 2012 V. B. Semenov det. 201’ ‘ Oxytelus jessoensis Bernhauer, 1907 , det. M. Gildenkov, 2021’ (cOS); 1♂, 2♀ ‘ Russia: Kamchatka, Bystrinsky Natural Park. Floodplain of Bolshaya Romanovka River ( Picea , fern, horsetail), 07.2015, leg. V. I. Lobanova’ ‘ Oxytelus jessoensis Bernhauer, 1907 , det. O. Semionenkov, 2021’ (cOS).

Diagnosis. Like O. ruthenus , Oxytelus jessoensis differs from O. assingi in the lighter coloration of the antennal base (segments 1–4) and mouthparts ( Schülke 2012; Semionenkov, Gildenkov 2022). O. jessoensis is noticeably different from them in the structure of abdominal sternite VIII ( Figs 9, 11, 12); the differences between O. assingi and O. ruthenus are limited only to the structure of abdominal sternite VIII ( Figs 11, 12). The width of the abdomen in O. assingi and O. ruthenus ( Figs 3, 4 ) ( Schülke 2012: 1660: Fig. 1 ) is slightly narrower than the width of the elytra, in contrast to O. jessoensis ( Fig. 1 ), whosewidth of the abdomen noticeably exceeds the width of the elytra, both in males and females. However, the three species differ most reliably in the details of their parameres structure ( Figs 13–15).

Some of the material we studied and presented in this article (see above), with the labels ‘ Oxytelus assingi Schülke, 2012 V. B. Semenov det. 2015’, was previously incorrectly identified and published ( Lobkova, Lobanova, Semenov 2017) as O. assingi . Another part of the material from the same work ( Lobkova, Lobanova, Semenov 2017) was identified by us ( Semionenkov, Gildenkov 2022) as O. ruthenus . This indicates that the species O. jessoensis , O. assingi and O. ruthenus are very difficult to distinguish, and given the cohabitation of O. jessoensis and O. ruthenus in Kamchatka, a detailed diagnosis of the species O. jessoensis may be relevant.

Discussion. Oxytelus (Tanycraerus) jessoensis Bernhauer, 1907 was described from Japan, from the island of Hokkaido (Jesso), vicinity of the Nemoro city, near Tokyo ( Bernhauer 1907). For a long time it could only be found in catalogs. Koch ( Koch 1932) gives the characters of O. jessoensis in the identification key, comparing it with the widespread and well-known species Oxytelus (Tanycraerus) laqueatus (Marsham, 1802) . According to Koch, the abdomen of O. jessoensis at its widest part is noticeably broader than the elytra, while it is noticeably narrower than the elytra in O. laqueatus ( Figs 1, 2 ). Koch also notes significantly coarser punctation of the elytra and head in O. jessoensis ( Koch 1932: 655) . A fairly detailed redescription of the species O. jessoensis was published in 1994 ( Ito 1994). In addition to the description, Tateo Ito provides photographs of the holotype and original labels and a drawing of abdominal sternite VIII with characteristic features ( Ito 1994: 42: Figs 1, 2 ). At the same time, the author notes that the species is known to him from a single specimen (male, holotype), with no data available for the female ( Ito 1994: 42). The last mention of O. jessoensis is found in V. Kastcheev’s identification key ( Kastcheev 1999: 154). He compares O. jessoensis with O. laqueatus and Oxytelus (Tanycraerus) altaicus noting a much coarser and denser punctation of the head, pronotum and elytra in O. jessoensis .

The material from Kamchatka (see above) was identified as O. jessoensis ( Figs 1, 5 , 9, 15) based on the descriptions in ( Bernhauer 1907; Ito 1994) and characteristic features in the structure of male abdominal sternite VIII ( Ito 1994: 42: Fig. 2 ). Indeed, O. jessoensis ( Fig. 1 ) has significantly coarser and denser punctation of the head, pronotum and elytra compared to the very similar body microsculpture of O. laqueatus ( Fig. 2 ) and O. altaicus ( Gildenkov, Semionenkov 2023: 42: Figs 1, 2 ). It is also confirmed that the width of the abdomen of O. jessoensis actually exceeds the width of the elytra ( Fig. 1 ), in contrast to O. laqueatus ( Fig. 2 ). The aedeagus of O. jessoensis was studied for the first time ( Fig. 5 ). It should be noted that its structure is noticeably different from the structure of the aedeagus of O. laqueatus and O. altaicus ( Fig. 6 ) ( Gildenkov, Semionenkov 2023: 42: Figs 3, 4 ), with significantly more developed parameres ( Fig. 6 ) ( Gildenkov, Semionenkov 2023: 42: Figs 3, 4, 5, 6 ). At the same time, O. laqueatus and O. altaicus are very close species not only in the structure of the aedeagus, but also in the structure of male abdominal sternites VII ( Gildenkov, Semionenkov 2023: 42: Figs 7, 8 ) and VIII ( Fig. 10), which makes them different from O. jessoensis ( Fig. 9). In coloration, coarse punctation of the head, pronotum and elytra, and structure of the aedeagus, O. jessoensis is most similar to the recently described ( Schülke 2012; Semionenkov, Gildenkov 2022) Oxytelus (Tanycraerus) assingi Schülke, 2012 ( Figs 3, 7 , 11, 13) and Oxytelus (Tanycraerus) ruthenus Semionenkov & Gildenkov, 2022 ( Figs 4, 8 , 12, 14).

Figures

Figs 1–8. Oxytelus (Tanycraerus) spp.: 1 — Oxytelus jessoensis Bernhauer, 1907, Kamchatka, male, dorsal view; 2 — Oxytelus laqueatus (Marsham, 1802), Smolensk Area, male, dorsal view; 3 — Oxytelus assingi Schülke, 2012, paratype, male, dorsal view; 4 — Oxytelus ruthenus Semionenkov & Gildenkov, 2022, holotype, male, dorsal view Scale bar: 1 mm. Aedeagus, ventral view: 5 — O. jessoensis, Kamchatka; 6 — O. laqueatus, Smolensk Area; 7 — O. assingi, paratype; 8 — O. ruthenus Semionenkov & Gildenkov, 2022, holotype. Scale bar: 0.25 mm Рис. 1–8. Oxytelus (Tanycraerus) spp.: 1 — Oxytelus jessoensis Bernhauer, 1907, Камчатка, самец, сверху; 2 — Oxytelus laqueatus (Marsham, 1802), СмоΛенская обΛасть, самец, сверху; 3 — Oxytelus assingi Schülke, 2012, паратип, самец, сверху; 4 — Oxytelus laqueatus (Marsham, 1802), гоΛотип, самец, сверху. Масштаб: 1 мм. ЭÃеагус снизу: 5 — O. jessoensis, Камчатка; 6 —O. laqueatus, СмоΛенская обΛасть;7 —O. assingi, паратип; 8 —O. ruthenus, гоΛотип. Масштаб: 0,25 мм