Australonura wellingtonia (Womersley, 1936)

Australonura wellingtonia (Womersley, 1936) View in CoL

( Figs 3–10; Tables 2–3)

Material examined: Three males and two females on slides. Australia, Tasmania, Satan’s Lair, S 42°43′10.1′′S, 146°33′15.8′′E, 17.XI.2022, decomposing logs, manual sampling, F.G.L. Oliveira leg. GoogleMaps

Redescription: Length of males 2.48–4.6 mm, females 2.63– 3.44 mm. Colour white in ethanol. No pigment. Habitus typical of the genus. Weak cryptopygy. Secondary granules conical ( Fig. 3E). Tertiary granules (elementary tubercles) well differentiated dorsally on head and body ( Figs 3A, 4A, 5A, 6A), papillate, grouped in conspicuous tubercles with reticulations ( Fig. 3F). Dorsal chaetotaxy constituted of ordinary chaetae and S-chaetae. Four kinds of dorsal ordinary chaetae ( Fig. 10C): strongly ciliated long (Ml) or short (Mc) thick macrochaetae, straight, with blun tips; ciliated acuminate macrochaetae (Ma); ciliated or smooth mesochetae (m); without microchaetae. S-chaetae much thinner than M, less than half the length of closest M ( Figs 4B, 5B, C, 6B–D).

Antennae shorter than head, less than two times as long as basis length ( Fig. 3A). Dorsally some tertiary granulation can be seen on Ant. I–IV ( Fig. 3A–C). Ant. I with seven chaetae, of which three dorsal strongly ciliated M. Ant. II with 11 chaetae, of which three strongly ciliated M dorsally. Ant. III with 17–18 ordinary chaetae; AIIIO with two thickened ms in a cuticular fold; two guard S, Sgv as thick and longer than Sgd, and thinner than Ant. IV S1-S8; one ventro-external ms more basally. Ant. IV with S1-S8 thick, 12 long ‘mou’ chaetae, one short ordinary chaeta (i), one small subapical organite almost entirely buried in the integument, and one bilobed apical bulb, fused to Ant. IV tip ( Fig. 10B).

Ocelli 2 + 2 without pigment, located on the edges of tubercle Oc ( Fig. 3D); their longer axis 1.8–1.9 times as long as Ocm socket diameter. Buccal cone moderately elongated ( Fig. 7). Maxilla styliform, mandible thin and probably tridentate. Labrum rounded apically, elongate, labral formula 0/2,4 ( Figs 7B, 10C, D). Labium long with four basal (E,F,G,f with F very long), three distal (a1,a2,p2), and three lateral chaetae (c,d,e); with two minute x-papillae ( Fig. 10D).

Dorsal head chaetotaxy and tubercles ( Table 2; Fig. 3A). With 10 tubercles well developed: (Cl + Af), 2 Oc, (Di + Di), 2 De, 2 DL, 2 (L + So). Central area (Cl + Af) with A, B, E, F, G chaetae (C, D, and O absent); elementary tubercle EE present on Af. (Cl + Af) tubercle partially fused to Oc in the middle zone ( Fig. 3D). Generally two chaetae on ocular tubercle, Oca absent or rarely present ( Figs 3D, 10A). Tubercles Di fused on the middle ( Fig. 3A), with about 28 elementary tubercles anterior to the line Di1–Di1 and eight posterior ( Fig. 10A). DL tubercle with 4 DL chaetae; L1 chaeta included in the DL tubercle of head ( Fig. 10A).

Postcephalic chaetotaxy and tubercles ( Table 3; Figs 4A, 5A, 6A). Tubercles well developed, especially laterally from Th. I to Abd. VI. Th. I with Di tubercles. Chaeta Di present on Th. I as a Mc. Tubercles Di very close from Th. II to Abd. IV. Tubercle Di of Th. II–III with three chaetae positioned on the tubercle [ cirrata type after Greenslade and Deharveng (1990)]. Tubercle De of Th. II–III with three chaetae and one S-chaeta. Tubercles De and DL separate on Abd. IV. Abd. V with tubercles Di fused, separated from De. Tubercle Di of Abd. V with two chaetae, Di 3 absent. Abd. VI bilobed. S-chaetotaxic formula: 2 + ms, 2/1,1,1,1,1 .

Legs ( Table 3; Fig. 8A–C). One ventral chaetae of the femur differentiated, longer than ventral side of femur. Tita without tenent hairs and without chaeta M; B4 and B5 longer than other chaetae of the Tita. Claw untoothed, not striated in its basal part, and devoid of secondary granulation.

Ventral chaetotaxy of VT and Abd. III–VI as in Figure 9A–C. Furcal rest with four or five chaetae, devoid of mi. Chaetae Ag 3 + 3. Male genital plate with 4 + 4 genital and 12 + 12 circumgenital chaetae ( Fig. 9C); female genital plate with 1 + 1 genital and about 12 circumgenital chaetae ( Fig. 9B).

Ratios. Abd. IV, Dil: Di2, 6–7: 4; Abd. V, Dil: Di2:GIII, 7–8: 3–4:6–7; dcA: GIII, 1: 6–7.

New mitogenomes

Our mitogenomic data matrix included 38 Arthropleona taxa, 15 of which (having absent furca) were phylogenetically analysed here for the first time: Neanurinae , Bilobella braunerae , Neanura muscorum , Rambutanura hunanensis , and Australonura wellingtonia ; Pseudachorutinae , Anurida granaria , Anurida granulata , Megalanura aff. tasmaniae , Womersleymeria aff. bicornis , and Holacanthella duospinosa ; Friesinae, Friesea truncata ; Hypogastruridae , Ceratophysella scotica , C. sigillata , Hypogastrura burkilli , and Xenylla mediterranea ; Onychiuridae , Hymenaphorura dentifera . The newly assembled mitogenomes of the three Neanuridae species are 16 742 bp, 16 128 bp, and 15 798 bp in length, respectively, to Womersleymeria aff. bicornis , Megalanura aff. tasmaniae , and Australonura wellingtonia . The most used initiation codons were ATT, ATG, and ATA, and the typical stop codon TAA was the most frequent, followed by TAG. The three mitogenomes have an average value of adenine and thymine accounting for 34% and 35.6% of nucleotides, respectively (AT content = 69.6%). The Pancrustacean ancestral gene order was observed in the new mitogenomes, which is also the most common arrangement among Collembola species ( Leo et al. 2019). A long intergenic space (between 230 bp to 878 bp in length) located at the gene junction of ND1 and trnS2 is present in all three sequences, this unusual feature was also described for the mitochondrial DNA of two Isotomidae species Cryptopygus antarcticus and C. terranovus (Carapelli et al., 2019) . Details of the genes’ features and the circular representation of the three mitogenomes are presented in the Supporting Information ( Figs S1–S 3; Tables S2–S 4).

Phylogenetic analyses

The tree presented in Figure 11 is a compilation of the results of ML and BI of 2733 amino acid sites. Comparing it to other trees generated using nucleotides, this was the most plausible result, in terms of support values and taxonomical information. Branches recovered in different positions in the tree generated with the same dataset using BI are marked with an asterisk. Trees generated with nucleotide data, the Astral species’ tree, and the maximum parsimony tree are presented in the Supporting Information ( Figs S4–S 7).