Acrotelsella parlevar Smith, 2016

Smith, Graeme B. & Mitchell, Andrew, 2022, On some Silverfish Taxa from the Mildura Region (Inland South-eastern Australia) (Zygentoma: Lepismatidae: Ctenolepismatinae), Records of the Australian Museum (Rec. Aust. Mus.) 74 (5), pp. 151-199 : 195-198

Acrotelsella parlevar Smith, 2016

Acrotelsella parlevar Smith, 2016: 66

Figs 157–159

Material examined. Holotype ♀ ( HW 1.55 ) TASMANIA: Travellers Rest, near Launceston 41.49103°S 147.07778°E, 17–23.iv.2015, W. & L. Clarkson, pitfall trap, dry sclerophyll forest, AMS K.261103 & K.261104 (on two slides); 1♀ ( HW 1.24 ) NEW SOUTH WALES: ca 15km south of Balranald 34.76606°S 143.53946°E 71m asl, 23.ix.2013, Graeme Smith , mallee leaf litter, AMS K.541625 (on two slides); 1 juvenile ♀ ( HW not recorded) same data as previous, AMS K.261322 (on two slides); 1♂ ( HW 1.15 ) same data as previous,AMS K.261323 (on two slides); 1♂ ( HW 1.19 ) same data as previous, AMS K.541626 (on two slides); 1 juvenile ( HW 0.70) same data as previous, AMS K.377959 (in alcohol); 1♂ ( HW 1.10 ) ca 135km west of Cobar 31.51686°S 144.48158°E 95m asl, 21.v.2012, Graeme Smith, wind blown leaf litter on red soil, AMS K.541639 (on two slides); 2♂, 1♀ 1 juvenile ♀ ( HW, 1.13, 1.10, 1.18, 0,88 respectively) same data as previous, AMS K.377972 (in alcohol); 1♀ ( HW 1.30 ) east of Cobar 31.52264°S 146.07185°E 264m asl, 22.v.2012, Graeme Smith, wind blown leaf litter on red soil, mostly Eucalyptus, AMS K. 541629 (on two slides); 2♀♀ 4♂♂ 1 juvenile ♀ ( HW not recorded), same data as previous, AMS K.377962 (in alcohol); 1 juvenile ♀ ( HW 0.68) Nangar N.P. near campground 33.41933°S 148.49969°E 470m asl, 7.vii.2016, Graeme Smith, bark spray to cypress pine, AMS K.377961 (in alcohol); 1 juvenile ♂ ( HW 0.88) VICTORIA: Hattah-Kulkyne N.P. dune near Lake Mournpell campsite 34.70198°S 142.33780°E 57m asl, 24.ix.2013, Graeme Smith, leaf litter on sand under small bush (small leaves—wattle? Hakea?) with Acrotelsella mallee sp. nov., AMS K.377960 (in alcohol); 1♀ ( HW 1.25 ) VIC: Sturt Highway, rest stop near South Australia border 34.27503°S 140.96759°E 37m asl, 7.v.2012, Graeme Smith, leaf litter mallee scrub, AMS K.541627 (on two slides); 1♂ ( HW 1.15 ) same data as previous, AMS K.377969 (in alcohol); 1♂ ( HW 1.25 ) same data as previous, AMS K.377970 (in alcohol); 1♂ ( HW 1.11 ) same data as previous,AMS K.377971 (in alcohol); 1♂ ( HW estimated 1.15) Murray-Sunset N.P. Pioneer track 35.03489°S 141.73909°E 59m asl, 26.ix.2013, Graeme Smith, under dead spinifex in mallee,AMS K. 541628 (on two slides); 1♂ ( HW 1.13 ) Murray-Sunset N.P. Pioneer track 35.03444°S 141.73926°E 52m asl, 26.ix.2013, Graeme Smith, Eucalyptus leaf litter on top of ridge (collected with Acrotelsella mallee sp. nov.), AMS K.541631 (on two slides); 1♀ ( HW 1.13 ) VIC: ca 1km south of Walpeup 35.14308°S 142.03095°E 84m asl, 26.ix.2013, Graeme Smith, shallow litter, Acacia ?, NMV gbs004056 (on two slides); 1♂ ( HW 1.11 ) Wyperfeld N.P., Desert track car park 35.60408°S 141.99718°E 78m asl, 28.ix.2013, Graeme Smith, leaf litter under pea or Acacia bush?, NMV gbs004063 (on two slides).

Other material whose relationship with A. parlevar requires further investigation. 1♂ ( HW 1.38 ) WESTERN AUSTRALIA: North West Cape, near Wabiri , inland side of road 21.834°S 114.079°E 10m asl, 28.ix.2008, Graeme Smith, under or within cracks of limestone rocks on red soil, WAM E113405 (in alcohol) ; 1♂ ( HW 1.15 ) same data as previous, WAM E113406 (on two slides) .

Supplementary description and description of male

Description as in Smith, 2016 with the following changes/ additions and changes to measurement range based on ten dissected sexually mature specimens from nine mainland localities. The larger size of the Tasmanian specimen may account for the larger number of macrochaetae reported in combs. All additional specimens were considerably smaller than the Tasmanian holotype.

Diagnosis. This species can easily be distinguished from other described Acrotelsella by the presence of only three papillae on the last article of the labial palp, the shape of the thoracic sterna and the arrangement of the sternal combs in over-lapping irregular rows and the simple ovipositor of the female.

Appearance: Scale pattern when live as in figure 158 with thin band of white scales along of the nota, dorsal surface including head with mottled grey scales, dorsal surface of legs light in colour. Antennae evenly light brown terminal filaments with inconspicuous darker and lighter annulations.

Body length: terminal filaments all broken but some at least 0.6 H+B.

Scales: Scales also confirmed to be present on third article of maxillary palp, found on top of head, on scape but not pedicel, present on terminal filaments.

Head: The small gap in the row of macrochaetae along the margin above the antennal bases is not always present; the distal annuli arranged in chains of 12 not six annuli, bearing rod-like basiconic sensilla type B and possibly type C. — Maxillary palp very long and thin, apical article 4–6 times longer than wide and about the same length as the penultimate article, apical article of labial palp expanded somewhat medially, the length to width ratio quite variable (0.8–1.7) however this may reflect the difficulties of measurement of material in alcohol; once slide mounted the shape of the ultimate article seems much more consistent.

Thorax: The described “very slight gap in the setal collar” is not consistently present, the chaetotaxy is weak in the medial region but a distinct gap was not usually present, the macrochaetae of the collar are pectinate and can be quite long; lateral margins with short, tapered and slightly pectinate setae along the margin (all lost except one which is short and slightly pectinate), these marginal setae almost absent from the anterior part of the margin, becoming more frequent posteriorly, with 7–8 combs of 1–3 macrochaetae along each margin. Two open trichobothrial areas; the posterior trichobothrial area is located about 0.70–0.77 along the margin and is associated with the last comb (N), this comb composed of 2–3 macrochaetae with the short trichobothrium at the mediad end and a cilium at the laterad end, the anterior trichobothrial area is located 0.33–0.41 and associated with comb N-3 (except in K.261323 here the N-1 comb appears to be missing from both sides), the comb composed of only a single macrochaeta with the trichobothrium between the macrochaeta and the margin and a cilium at the mediad side of the macrochaeta (in one specimen (K.541627) a second macrochaeta is present on both anterior trichobothrial areas (left and right sides) and on another (K.261323) a second macrochaeta is present only on one side); all combs associated with a few setulae. Posterior margin with 1+1 combs of eight macrochaetae in the Tasmanian specimen but only 4–7 insertion points on the mainland material, the outermost insertion point is almost certainly a long, thin trichobothrium-like seta (definitely present in NMV gbs004063); the gap between the posterior combs 44–52% the maximum width of the pronotum. — Mesonotum with trichobothrial areas located 0.49–0.62 and 0.78–0.87 along the margins with 8–11 combs of 2–4 macrochaetae, the metanotum with trichobothrial areas located 0.63–0.74 and 0.82–0.87 along the margins with 8–10 combs of 2–4 macrochaetae, in one specimen (K.541625) a third trichobothrium is present on one side.

Prothoracic sternum 0.91–1.08 times as long as wide at its base, somewhat pointed apically rather than round, antero-lateral corners with fields of 20–40 small simple setae, posterior three quarters of lateral margins with fringe of setae and some cilia as well as 4–8 eight small groups of 1–13 macrochaetae almost always arranged in 2–3 irregular overlapping rows. — Mesosternum a little larger than prosternum and slightly less acute apically (L/ W 0.91 –1.09) with (2–4)+(2–4) groups or combs distally of 1–16 pectinate macrochaetae in overlapping irregular rows. — Metasternum wider and shorter (L/ W 0.76 –0.91) with 1+1 (rarely 1+2) groups of 2–19 pectinate macrochaetae arranged in 2–4 overlapping rows plus 1+1 single submarginal macrochaetae more distally.

Tibia L/W ratio of legs PI 2.3–3.1, PII 2.9–3.2, PIII 3.4–4.4; tarsi L/W ratio PI 5.9–8.0, PII 6.2–10.1, PIII 8.1–11.7.

Abdomen: Urotergite X acutely triangular (47–53° in females, 54–60° in males), wider at base than long (L/ W 0.63 –0.85) with (4–5)+(4–5) combs of 1–7 macrochaetae per comb; the number of macrochaetae per comb as in Table 8.

Urosternites III–VII with 1+1 lateral combs of 11–21 pectinate macrochaetae; the distance between the lateral combs 2.4–5.8 times the average width of these combs, the ratio being largest on urosternite III and decreasing posteriorly.

Coxites VIII with almost right-angled inner angle (86–106°) with curve occupying ⅓–½ of posterior margin. Coxite IX with long rounded internal process about 2.4–4.2 times longer than wide at its base and almost 4.5–8.9 times longer than the short pointed external process; with a long subtly pectinate macrochaeta mediad to the base of each stylus. — Ovipositor not very long (1.7–1.9 HW), about 16–20 articles in total.

0.1 mm.

Male. Similar to female except coxites VIII entire ( Fig. 159 ) with 1+1 combs of macrochaetae. Coxites IX in ♂ separated each side with a long subtly pectinate macrochaeta mediad to the base of each stylus, reaching almost to the apex of the internal process). External and internal margins of internal process with some moderately strong setae macrochaetae; ventral surface of process with many long thin setae inserted parallel to the external margin. In half of the slide mounted specimens examined (K.261323, K.541626 and K.541631 all of which were males) one or two short transverse combs of 1–3 pectinate macrochaetae are present ( Fig. 159 ) but absent from the remainder including all females. Outer process small triangular with several stout pectinate setae along the outer margin. Penis typical with numerous glandular setae apically, each set on a protuberance. Parameres absent.

Habitat. This species is found in dry leaf litter, often that accumulating under bushes.

Remarks

This species is most closely related to A. thommoi sp. nov. and A. tanni sp. nov. It can easily be distinguished from either of these species by the combs on the thoracic sterna. The macrochaetae in these combs on A. parlevar are generally irregularly arranged, almost looking like narrow bushes of macrochaetae in extreme examples whereas these combs on the other two species are arranged in lines, sometimes a little curved and sometimes with one or two macrochaetae off-set a little from the line but never in highly irregular groups. Acrotelsella parlevar can further be distinguished from A tanni sp. nov. which has five papillae on the ultimate article of the labial palp (versus three in the other two species) and from A. thommoi sp. nov. which has more distinct regions of pigment (versus overall lightly pigmented in A. parlevar ) and by the number of macrochaetae associated with the anterior trichobothrial area on the metanotum (always two macrochaetae in A. parlevar and A. tanni sp. nov. but usually only one macrochaeta in A. thommoi (one example was seen with two macrochaetae but only on one side). Females of A. parlevar also have less round posterior margin on coxites VIII and fewer divisions in the ovipositor (15–20 versus 25–29).

Other species known to have only three papillae on the labial palp include Acrotelsella giubana from Somalia and Acrotelsella suqutrensis from Yemen which differ from the Australian species in many ways such as the chaetotaxy of the frons and the combs or shape of the thoracic sterna.

The range of this species is now known to extend over 1000 km north of its type locality in Tasmania and it seems to be fairly common within the drier parts of NSW and Victoria (see map, figure157). We also have specimens from North-West Cape in Western Australia that may belong to this species or else are very close to it. We did not obtain good sequence data (50% COI) but this data places the specimens with A. parlevar . Morphologically they also fit well with A. parlevar , having the same irregular combs on the thoracic sterna and three labial palp papillae but differ slightly in that the posterior corner of urotergite X is somewhat rounded where it is very pointed in all other specimens examined and there is a single comb on just one side of urosternite II, the latter character probably being anomalous.

Figures

Figure 157. Known distribution of Acrotelsella parlevar and a closely related taxon.

Figure 158. Acrotelsella parlevar sp. nov. Walpeup

Figure 159. Acrotelsella parlevar Smith ♂ (K.541626) (159) urosternite VIII, coxites IX and penis. Scale bar =