Entomobrya assuta Folsom, 1924 sensu Katz et al., 2015

Jordana, Rafael & Greenslade, Penelope, 2020, Biogeographical and ecological insights from Australasian faunas: the megadiverse collembolan genus, Entomobrya (Entomobryidae), Zootaxa 4770 (1), pp. 1-104 : 20-21

Entomobrya assuta Folsom, 1924 sensu Katz et al., 2015

( Figs 1C , 8 A–G)

Type locality.: Vermont, New York, North America .

Material examined. Two females, WA, Barrow Island , on wharf during quarantine inspection, on imported timber, - 20.78778°S, 115.3991°E, 3m asl, 27.vi.2011, [ SAMA] . Several specimens, Barrow Island , beside plant construction, airport and new village, in Triodia vegetation, pitfalls and Winkler extraction, N. Gunawardene leg., all collections previously determined as E. marginata ( PG) .

Redescription based on Australian material. Size. 2 mm female adult, 1.5 mm female sub-adult. Body shape. Dorso-ventrally flattened.

Colour. Dorsal colour pattern dark blue with darkened band on the hind part of each tergite ( Fig 1C ).

Head. Apical bulb of antennal segment IV bilobed, long differentiated smooth chaetae on the ventral side of antennal segment 1–4–plus short chaetae. Prelabral chaetae clearly ciliated. Distal margin of each labral papillae with 2–3 small spine–like projections. Eyes G and H small and subequal Eyepatch with five chaetae.

Thorax and abdomen. Thoracic chaetotaxy extremely reduced. A row of microchaetae present along the entire posterior margin of Th II and Th III (not displayed in figures). Trochanteral organ with triangular chaetae pattern and up to 11 chaetae. Unguis with 4 inner teeth; paired teeth located approximately in the middle of inner unguis length. Dorsal tooth intermediate, 2 lateral basal teeth. Two unpaired teeth on the internal edge of the unguis, unguiculus serrate on external edge ( Fig. 8A ).

Chaetotaxy. Dorsal head chaetotaxy at figure 8B; Mc A 6, M 3, S’ 0, S 0, S 1, S 4i, always absent; M 1, M 2 and M 4 present; Ps 2 and Ps 5 present. Th II, with a 5 Mc ( Fig. 8C ) Th III, with 7 Mc: a 5, a 6, m 5, m 6, m 7, p 4, and p 6; Mc a 1, a 2, and a 3 absent. Chaetotaxy of zone Pm extremely reduced for both thoracic segments, without Mc. Abdominal chaetotaxy reduced.Abd I with 3 Mc m 2, m 4, and m 6 ( Fig. 8D ); a row of mic along entire posterior margin present (not displayed in the figure). Abd II with 3 Mc: m 3, m 3e, and m 5 ( Fig. 8E ). Abd III with 3 Mc: m 3, pm 6, and p 6. ( Fig. 8F ). Abd IV with 3 inner Mc B 5, B 6 and A 6 ( Fig. 8G ). Manubrial plate with 2 chaetae and 2 pseudopores. Mucronal teeth subequal.

Remarks. Entomobrya assuta from Barrow Island has a macrochaetal formula of 4,1,0,1,2/0,1/0,2/0,0,1/0,0,0, 1,2 which unique for an Entomobrya species. The Barrow Island specimens are similar in most aspects to Entomobrya assuta from the North America whose formula is 4(5),1,0,1,2/0,1/0,2/0,1,1/0,0,1,1,2 see Katz et al. (2015). The colour pattern is different, but some specimens of E. assuta , described by Katz are a uniform blue. The remaining morphological characters are similar to North American E. assuta , except the number of chaetae in the trochanteral organ. Of 44 characters, only 2 are different: a 2 as microchaetae on Abd II and C 1 on Abd IV present in E. assuta and absent in the Australian specimens. All other characters are identical. Specimens from both regions have the most reduced chaetotaxy of any Entomobrya .

This is the first exotic species to be recorded from Barrow Island and was introduced to the Class A nature reserve during construction of the gas processing plant on the island by the Chevron Mining Company. This was despite stringent quarantine control on imports and fumigation of all imported timber. It is an example of the occasional ineffectiveness of fumigation in killing adventitious specimens. The timber was imported for scaffolding but its country of origin is unknown.

Figures

FIGURE 1. Habitus and colour of: A, Entomobrya additae sp. nov.; B, Entomobrya albocincta; C, E. assuta; D, Entomobrya bioblitzi, sp. nov.; E. Entomobrya boreensis, sp. nov.; F, Entomobrya caputovisensis sp. nov.; G–H, Entomobrya charlotteensis sp. nov. 7, male, H, female; I, E. clarki; J–K, Entomobrya darelis sp. nov.; L, Entomobrya driesseni sp. nov.; M, Entomobrya durrasensis sp. nov.; N, Entomobrya grisacea sp. nov.; O, Entomobrya herbacea sp. nov. Bar=0.5 mm.

FIGURE 8. Entomobrya assuta. Line drawings A–G: A, tip of leg 3 (bar=0.025 mm); B, head chaetotaxy (bar 0.4 mm); C, Th II chaetotaxy; D, Abd I chaetotaxy; E, Abd II chaetotaxy; F, Abd III chaetotaxy; G, Abd IV chaetotaxy. Bar C–G=0.125 mm.