Oligaphorura pingicola (Fjellberg, 1987)

Babenko, Anatoly B. & Fjellberg, Arne, 2015, Subdivision of the tribe Oligaphorurini in the light of new and lesser known species from North-East Russia (Collembola, Onychiuridae, Onychiurinae), ZooKeys 488, pp. 47-75 : 58-60

Taxon classification Animalia Collembola Onychiuridae

Oligaphorura pingicola (Fjellberg, 1987)

Onychiurus (Archaphorura) pingicolus Fjellberg, 1987: 285.

Oligaphorura pingicola (Fjellberg): www.collembola.org

Material.

holotype, ♂, "Alaska, Prudhoe Bay, Dryas -turf on pingo, 16 viii 1976" (CNC 165048, type No 20099); paratypes, 5♀ and ♂, same sample (CNC 165139, type No 200100), all A. Fjellberg leg.

Additional material.

50 specimens, Russia, Yakutia (Sakha Republic), Suntar-Khayata Mt. Range, upper reaches of Kyubyume River [63°13'N, 139°32'E], various sites, viii 2002, O. Makarova leg.; 25 specimens, Magadan District, upper reaches of Ola River [60°39'N, 151°16'E], snow fields, 1100-1200 m alt., A. Babenko leg.; 4 specimens, Magadan District, Bolshoi Annachag Mts. Range, upper reaches of Kolyma River, field station “Aborigen” [61°56'N, 149°40'E], thick moss among rocks near snow field, 26 vii 1979, A. Fjellberg leg.; 4 specimens, same region, lichen/ Ledum in northern slope, 28 vii 1979, A. Fjellberg leg.; 1 specimens, same region, Pinus pumila and lichen cover on hillside, 20 vii 1979, V. Behan leg.; 2 specimens, same region, alpine study area (lichen, moss, Dryas , Empetrum ), 26 vii 1979, V. Behan leg.

Redescription.

Colour white. Granulation distinctly enlarged on Abd.6 and on head. Size 1.0-1.1 mm. Body shape cylindrical. Antennae about as long as head, Ant.3-4 broad, club-like. Ant.4 with a subapical spherical organite and a microsensillum located in proximal row of setae. AO consists of 5 long and thin papillae, two sensory rods, two granulated sensory clubs (internal almost straight, external much larger and bent), 5 guard setae and a lateral microsensillum which set below the organ. Ant.1 and 2 with 8-9 and 15-16 setae respectively. PAO with 2-3 elongated lobes, much longer than nearest pseudocellus. Labrum with 4/5-2-2 setae. Apical part of labium with thick terminal setae on papillae A and C, 6 long guard setae and 6 proximal setae present, basal fields with 4+(5)6 setae. Maxillary palp simple with two sublobal hairs.

Pseudocellar formula (pso) as follows, dorsal: 32/033/33343, ventral: 2/000/0000, parapseudocelli (psx) 10/000/222201+1m. Each subcoxa with one pso and one psx, psx present also on femora and on border between Ant.3-4. Granulation rather fine but clearly coarser around pseudocelli and on Abd.6. Dorsal chaetotaxy almost symmetrical, setae smooth and clearly differentiated, sensory setae more or less distinct, usually 2/011/222211. Th.1 with 7-8 setae on each side, both Th.2 and 3 with lateral ms, p1 on head and Th.2-3 usually moved forward in relation to other medial p-setae. Abd.5 with microsetae m1 thin and curved, clearly shorter than mesosetae a1 and p1. Unpaired seta d0 on head absent, Abd.5 frequently with one unpaired axial seta in p-row, two axial setae present on Abd.6, a0 shorter than a2. Thoracic sterna of both Th.2 and 3 with 1+1 setae along ventral line. Furca shaped like a small fold in some distance from anterior border of Abd.4, in juveniles furcal field with 4+4 setae between proximal q-setae and the cuticular fold (Fig. 24), adults with some additional setae in intermediate position forming 4 more or less regular rows as typical for Oligaphorura (Fig. 23). Ventral tube with 8-9 distal and (1)2 proximal setae at base. Subcoxae with 4(5-6)-5(6)-5(6) setae, tibiotarsi with 20-20-19 setae: each distal whorl (A+T) with 11 setae, whorl B with 7-7-6 setae, setae M and Y present on all tibiotarsi. Unguis without inner tooth but usually with small and hardly visible lateral teeth present, unguiculus with small basal lamella about 3/4 as long as unguis. Anal spines bent, rather thick, set on low papillae. Males present.

Remarks.

The above redescription is in full accordance with the original one, adding a few details. While originally described from Alaska, Fjellberg (1987) also remarked that two specimens of the main form are also seen from alpine meadows at Aborigen, USSR (Magadan Reg.). In fact the species seems to be widespread and common not only in the Magadan Region but also in inner parts of the eastern Palaearctic (Suntar-Khayata Mts. Range, Yakutia). Fjellberg (1987) mentioned two distinct forms for Alaska differing in mutual position of setae on Abd.5 and in level of granulation. Only the main form seems to be present in the eastern Palaearctic.

Oligaphorura pingicola shares the number of dorsal and ventral pseudocelli with at least five known species of the tribe, namely Oligaphorura koreana , Oligaphorura nataliae , Dimorphaphorura raxensis , Dimorphaphorura chatyrdagi , and Dimorphaphorura sanjiangensis . Oligaphorura koreana is very similar to Oligaphorura pingicola , differing by fewer tibiotarsal setae (19-19-18 versus 20-20-19) and by absence of psx ( “indistinct”). The absence of psx is also characteristic for Oligaphorura nataliae which differs from Oligaphorura pingicola in having 7 long guard setae on labial palp and absence of ms on Th.3, as well as 2 setae of the proximal row on labrum (4/7 as a whole). Dimorphaphorura raxensis has 9 distal setae on tibiotarsi, full number of labral setae and ABC type of labium ( Weiner and Kaprus’ 2014). Dimorphaphorura chatyrdagi can easily be distinguished due to reduced tibiotarsal chaetotaxy with only 5 distal setae, whereas Dimorphaphorura sanjiangensis apart from the chaetotaxy of the sternum of Abd.4 differs in labium type (A versus AC) and identical number of tibiotarsal setae on all legs (20-20-20 versus 20-20-19).

Oligaphorura tottabetsuensis (Yosii, 1972), a species known from northern Japan, probably also belongs to the same group although the reported number of dorsal pseudocelli is slightly different (32/033/33333). The species is in need of redescription.