Oligaphorura arnei, Paśnik & Kaprus’, 2019

Paśnik, Grzegorz & Kaprus’, Igor, 2019, A new species of Oligaphorura Bagnall, 1949 (Collembola: Onychiuridae) from Alaska, Zootaxa 4712 (2), pp. 293-295 : 293-295

Oligaphorura arnei sp. nov. ( Figs 1–8 )

urn:lsid:zoobank.org:act:50761D13-FDD7-4861-A4CE-CC9CCE05D790

Type material. Holotype: male (mounted on slide), USA, Alaska, Canning River Delta, in owl mound on the tundra, 23.VII.1980, leg. S.F. MacLean. Paratypes: 2 males and 3 females (mounted on slides), the same data as holotype (ISEA— 3 paratypes: 1 male and 2 females, SNHM—holotype and 2 paratypes: 1 male and 1 female) .

Description. Holotype length 1.26 mm, length of paratypes: 1.23–1.39 mm (females) and 1.23–1.38 mm (males). Shape of body cylindrical ( Fig. 1 ). Colour in alcohol white. Granulation homogenous, with coarse granules around all dorsal pseudocelli. Usually 15–17 grains around each pseudocellus. Antennae 0.8–0.9 times as long as head. Antennal segment I with 9 chaetae, antennal segment II with 17 chaetae. Sensory organ of antennal segment III consisting of 5 guard chaetae, 5 papillae, 2 smooth sensory rods, 2 granulated sense clubs (internal clubs straight, external clubs bigger and bent) ( Figs 2–3 ), ventro-lateral sensillum present. Antennal segment IV with subapical organite and microsensillum ( Fig. 2 ).

Postantennal organ vesicle with three lobes, located in small cuticular depression and 1.7–1.8 as long as nearest pseudocellus ( Fig.4 ). Labral formula of chaetae: 4/3,4,2. Maxillary palp simple with 2 sublobal hairs. Labial palp of AC type. Labium with 6 proximal, 4 basomedian and 6 basolateral chaetae.

Pseudocellar formula dorsally: 32/033/34(5)443 (1+1 pseudocellus located on abdominal pleura I–III), ventrally: 2/000/01110(1) ( Figs 1, 5 ). Parapseudocellar formula ventrally: 0/000/100000 ( Fig. 5 ). Subcoxa1 of I, II and III legs with 2,2,2 pseudocelli (one dorsal and one ventral) and 1,1,1 parapseudocellus respectively.

Dorsal chaetotaxy with some asymmetry, as in Fig. 1 . Chaetae relatively short, weakly differentiated into macro- and microchaetae. Sensory chaetae s not differentiated. Thoracic tergum I with 7+7(6, 8) chaetae. Thoracic terga II and III with lateral microsensilla ( Fig. 1 ). Abdominal tergum V without axial chaetae. Abdominal tergum VI with medial chaeta a0 and p0. Subcoxae 1 of legs I–III with 4,5,5 chaetae respectively.

Thoracic sterna I–III with 0+0, 1+1, 1+1(2) chaetae respectively. Ventral tube with 7+7(8) chaetae, and 1–2+1–2 chaetae at base. Chaetotaxy of abdominal sternum IV as in Fig. 5 . Furcal vestige in form of cuticular furrow. Chaetotaxy of manubrial field consist of 4 chaetae in ma -row, 4 chaetae in mm’ -row, 4 chaetae in mm -row and 4(5) chaetae in mp -row ( Fig. 5 ).

Tibiotarsi I–III with 20, 20, 19 chaetae respectively. Distal tibiotarsal whorl with 11 chaetae. Claw with only lateral denticles ( Figs 7-8 ). Empodial appendage with distinct basal lamella and as long as 0.7 of inner edge of claw ( Fig. 7 ). Anal spines 0.65 times of inner claw edge and 2.4 times as long as their basal diameter.

Etymology. The species is dedicated to Arne Fjellberg, a well-known specialist on Collembola , who made the new species available for study.

Discussion. The new species is similar to such congeners as O. pingicola ( Fjellberg, 1987) , O. reversa ( Fjellberg, 1987) , O. koreana ( Weiner, 1994) , O. interrupta ( Fjellberg, 1987) and O. nuda ( Fjellberg, 1987) by having 033 pso on thoracic terga I–III, tibiotarsus of leg I–III with 11 chaetae in distal whorl, microsensillum ms on thoracic tergum III and furcal vestige in a form of cuticular furrow. Oligaphorura arnei sp. nov. is distinct from all these species by having different abdominal dorsal pso formula 34(5) 443 in new species. 33343 in koreana and pingicola , 3(4),3(4),3(4),(4)5,3(4) in interrupta and 44454 in nuda and reversa ) the subcoxa1 of I, II and III legs with 2,2,2 pseudocelli (1,1,1 in all mentioned species) and by the detail of chaetotaxy of manubrial field (additional mm’ -row of chaetae). In addition, in contrast to all mentioned species, O. arnei sp. n. has pso on abdominal sterna.

Figures

FIGURES 1–8. Oligaphorura arnei sp. nov.: 1, Habitus and dorsal chaetotaxy; 2, Dorsal side of Ant. III and IV; 3, Sensorial elements of AIIIO; 4, PAO and anterior cephalic pso; 5, Chaetotaxy of Abd. sterna II–VI; 6, Chaetotaxy of Abd. terga V-VI; 7, Tibiotarsal chaetotaxy and claw of leg III; 8, Claw of legs III in ventral view.