Asterochiton fagi ( Maskell, 1890 )

Martin, Nicholas A., 2020, Revision of the whitefly genus, Asterochiton Maskell (Hemiptera: Aleyrodidae) from New Zealand, a study of intraspecific variation, Zootaxa 4859 (3), pp. 301-341 : 321-322

Asterochiton fagi ( Maskell, 1890)

Figures 8 A–F.

Aleurodes fagi Maskell 1890: 175 , pl.13, figs. 25, 26; 1896: 432. Aleyrodes fagi Maskell, Cockerell, 1902: 281 ; Kirkaldy, 1907: 53; Quaintance, 1908: 6.

Dialeurodoides fagi (Maskell) , Quaintance & Baker, 1914: 99.

Asterochiton fagi (Maskell) , Quaintance & Baker, 1915: xi; Dumbleton, 1957, pp. 150–151, figs. 11–12.

Diagnosis. The distinctive feature of this species is that on each side there are the 12±1 strong lateral setae in the submargin. There are normally 6 in the cephalothoracic region, 4 before and 2 after the thoracic pore, two less than the maximum found in the genus. The presence of 6 abdominal lateral setae is also distinctive.

Puparium ( Figs. 8 A–B). Oval; dark brown in submedian area of dorsal disc, with an unpigmented band on posterior of prothoracic segment; found on under surface of leaves; widest at abdominal segments II & III; emarginated at thoracic and caudal tracheal pores; “Raised on vertical palisade of wax” ( Dumbleton 1957). Length, Lectotype 1.35 mm, range 1.0 – 1.45 mm (mean 1.29); width, Lectotype, 1.02mm, range, 0.78 – 1.09 mm (mean 0.96). Caudal and thoracic tracheal pores shallow, narrowly invaginated with 2–3 teeth ( Figs. 8 D–E). Margin finely crenulated ( Figs. 8 D–E), 9–13 crenulations in 0.1 mm.

Dorsum. Finely sculptured verging to linear markings marginally ( Figs. 8 D–E). Submargin 60 µm wide with a narrow area, 14 µm, with dense crenulation by the margin ( Figs. 8 D–E). Tiny circular pores on cephalothoracic and abdominal discs. Cephalothoracic (pro-, meso- & metathoracic) and abdominal depressions conspicuous. Abdominal segment VII narrow medially, less than half length of segment VI, 33 µm, range 15–40 µm (mean 31) ( Fig. 8C ). Transverse moulting sutures extending to margin. Pro-mesothoracic and meso-metathoracic sutures, and abdominal segmentation prominent, reaching subdorsal area. Vasiform orifice located anterior of caudal tracheal opening by at least its own length. Caudal furrow distinct.

Vasiform orifice ( Fig. 8C ). Subcordate; length 90 µm, range 75–100 µm, width 68 µm, range 55–75; open and pointed posteriorly, floor reticulated; operculum sub-cordate, covering half the length of orifice, length 41 µm, range 38–45 µm, width 52 µm, range 45–55 µm; lingula exposed, not reaching posterior margin of the vasiform orifice, terminal end slightly expanded and bluntly pointed, 46 µm, range 35–55, two subapical setae 24 µm, range 18–33 µm.

Venter. Thoracic tracheal folds present, no stippling; caudal fold not seen. Legs and antennae present, basal and terminal segments of legs 2 and 3 with tiny seta ( Fig. 8F ). Adhesive sacs present. Ventral setae 26 µm, range 20–33, distance apart 75 µm, range 63–88 µm, near anterior end of vasiform orifice. Anterior abdominal spiracle on segment 2, posterior spiracles near vasiform orifice.

Chaetotaxy. Eighth abdominal setae, 7 µm long, anteriad of vasiform orifice; 6 pairs of cephalothoracic lateral setae (4 pairs anterior & 2 pairs posterior to thoracic pore) and 6 pairs of abdominal lateral setae, 70–135 µm long, submarginal, mesad and close to the boundary of the dense submarginal crenulation; between the thoracic pore and the transverse suture, on one specimen 3 setae on one side and two specimens had 1 seta on one side. Caudal setae 75–125 µm. Anterior marginal setae 10–18 µm, posterior marginal setae 10–28 µm.

Material examined. Lectotype: Aleurodes fagi puparium 1889 W.M.M. Lectotype Aleurodes fagi Maskell, 1890 c .f. Dumbleton (1957). Front left corner of puparium damaged and part missing. Now held in NZAC.

Other material: Maskell Duplicates, 3 slides, each with 1 puparium, parasitoid exit hole, one also has fungal hyphae; 2 puparia (slide 94-004b), TO, Kaimanawa North Forest Park, Clements clearing, 4 December 1993, PK Buchanan, on Nothofagus menziesii ; 2 puparia (slide 03-185), NN, Korere Tophouse Rd, near Beebys track, 22 Sep 2003, FL Henderson, Nothofagus menziesii , underside leaf; 5 puparia (slide 03-187), NN, Korere Tophouse Rd, by Tophouse T. junction, 22 September 2003, FL Henderson, on Nothofagus menziesii , underside leaf; 2 puparia (slide 03-191), NN, Harwoods Hole Tk, by first pond, 23 Sep 2003, RC Henderson, Nothofagus menziesii underside leaf.

All specimens deposited in NZAC (Auckland, New Zealand) .

Host plant. Lophozonia menziesii (Hook.f.) Heenan & Smissen ( Nothofagaceae ), previously Nothofagus menziesii (Hook. f.) Oersted.

Distribution. Type locality, Inangahua, West Coast, South Island. The species has also been found in the Nelson Region of the South Island and in central North Island.

Remarks. Variation was found number of Cephalothoracic lateral setae between the thoracic pore and transverse suture. Normally there are 2 setae, but specimens were found with 1 and 3 on one side.

Figures

FIGURE 8. Asterochiton fagi (Maskell, 1890) puparium. A. Dorsum line drawing, B. Dorsum slide mount, C. Abdominal segments VI, VII and vasiform orifice, D. Caudal pore and caudal setae, E. Thoracic pore, tracheal fold and transverse suture, F. Antenna and legs.