Micranurida pygmaea Bӧrner, 1901 (a species complex)

Table 1

Studied material. Main form: 5 females, Khabarovsk Territory, Lazo District, mountain range «Arseniev’s granites», Mount Arseniev, ~ 1500 m alt., subalpine belt with Pinus pumila, litter and soil, 08 July 2019. A. Brinev leg. ; 1 juvenile, same region, upper reaches of Katen River, Ko Mountains, ~ 1500 m alt., subalpine belt with P. pumila, soil, 27 June 2018; A. Brinev leg. ; 12 females and 2 juveniles, Southern Primorye, Partisan District, Mount Olkhovaya, 43°20.83'N 133°39.38'E, ~ 1600 m alt., subalpine belt with P. pumila, litter and soil, 20 August 2018. M. Potapov, Yu. Shveenkova & A. Kuprin leg. ; 1 female, same region, Chuguev District, National Park «Zov Tigra», Mount Oblachnaya, Ussuri River valley, coniferous forest, 43°38.90'N 134°11.87'E, ~ 1200 m alt., rotten wood, 19–20 September 2018. A. Kuprin leg. ; 3 females, same data, but subalpine belt with P. pumila, 43°41.70'N 134°11.98'E, ~ 1850 m alt., litter and soil, 19–20 September 2018. A. Kuprin leg. ; 1 juvenile, Southern Primorye, Ussuri State Nature Reserve, valley of Anikin River, broadleaf forest, litter, 43°40.10'N 132°29.91'E, ~ 150 m alt., 13 August 2017. N. Kuznetsova, A. Kuprin & A. Geraskina leg.

Form A: 5 females and 1 juvenile, Far East of Russia, Amur Region, Zeya State Nature Reserve, ~ 300 m alt., mixed dry forest (poplar, birch, cowberry), 22 August 2014. M. Potapov & N. Kuznetsova leg. ; 2 juveniles, Khabarovsk Territory, Lazo District, mountain range «Arseniev’s granites», valley of Malyi Katen River, 500-600 m alt., mixed forest, rotten wood, 08 July 2019. A. Brinev leg. ; 1 female, same area, date and collector, ~ 900 m alt., coniferous forest belt, rotten wood; 1 juvenile, same region and collector, upper reaches of Katen River, Ko Mountains, ~ 500 m alt., mixed forest, litter, 01 July 2018 ; 1 female and 1 juvenile, same area, date and collector, but ~ 970 m alt., coniferous forest, rotten wood; 1 female, same region, Komsomolsk State Nature Reserve, Anyuinski National Park, Anyui River, mixed coniferous-broadleaf forest, 49°21.81'N, 137°42.14'E, ~ 200 m alt., litter, 08. July 2018. N. Kuznetsova, A. Kuprin & A. Geraskina leg. ; 2 females and 1 juvenile, Southern Primorye, Partisan District, Mount Olkhovaya, mixed forest in valley, 43°18.35'N 133°40.07'E, ~ 500 m alt., litter, 20 August 2018. M. Potapov, Yu. Shveenkova & A. Kuprin leg. ; 1 juvenile, same area, date and collectors, but 43°20.25'N, 133°39.69'E, ~ 1380 m alt., coniferous forest, rotten wood; 1 female and 1 juvenile, same region, Chuguev District, National Park «Zov Tigra», Mount Oblachnaya, Ussuri River valley, coniferous forest, 43°38.90'N 134°11.87'E, ~ 1200 m alt., litter, 19–20 September 2018. A. Kuprin leg. ; 1 juvenile, same region, «Kedrovaya Pad» State Nature Reserve, mixed coniferous ( Pinus koraiensis) -broadleaf forest, 43°6.88'N 131°29.23'E, ~ 120 m alt., litter, 27 July 2016. N. Kuznetsova & M. Potapov leg. ; 1 female, same region and collectors, Ussuri State Nature Reserve, forest with P. koraiensis on slope, 43°38.88'N 132°21.09'E, ~ 200 m alt., litter, 22 July 2016 ; 2 juveniles, same region,~ 30 km SE of Chuguevka, mixed forest, 44°1.32'N 134°9.02'E, ~ 500 m alt., 11 August 2017. N. Kuznetsova, A. Kuprin & A. Geraskina leg. ; 1 female and 2 juveniles, same region and collectors, Sikhote-Alin State Nature Reserve, coniferous forest with Rhododendron brachycarpum, 45°8.30'N 135°53.22'E, ~ 930 m alt., litter, 08 August 2017 ; 1 female, Khabarovsk Territory, Komsomolsk State Nature Reserve, Anyuinski National Park, Anyui River, mixed coniferous-broadleaf forest, 49°21.81'N, 137°42.14'E, ~ 200 m alt., litter, 08 July 2018. N. Kuznetsova, A. Kuprin & A. Geraskina leg

Form B: 3 females and 1 juvenile, Southern Primorye, Chuguev District, National Park «Zov Tigra», Mount Oblachnaya, Ussuri River valley, coniferous forest, 43°38.90'N 134°11.87'E, ~ 1200 m alt., rotten wood, 19–20 September 2018. A. Kuprin leg.

Remarks. Three forms may be distinguished within this complex in the Russian Far East, all quite clearly separated both morphologically (see Table 1) and in habitat. The first one, being most consistent with the modern description of the European populations of M. pygmaea (Fjellberg 1998, p. 75), is mainly confined to the subalpine belt at altitudes over 1500 m. The second form (form A) is characterized by the presence of only 1+1 ocelli, the absence of colouration (except for the ocelli), slightly widened sensilla on Th. II and Abd. IV and 17–17–16 setae on the tibiotarsi, respectively (not only M-seta as in the first form, but also A4 absent). Contrary to the first form, it occurs only in lower-mountain mixed and coniferous forests. There are also few specimens of the third form (form B) which differs from the second only in the complete absence of ocelli. It is likely that at least some of these «forms» represent isolated species, but taking into account the high variability of M. pygmaea described for European populations of this widespread species (Fjellberg 1998), as well as a large number of closely related European species that are rather poorly defined and difficult to identify (Fjellberg 1998, p. 77), the description of these Far Eastern forms as independent species seems to be premature.