Aacanthocnema dobsoni Froggatt
Creators: name: Taylor, Gary S.
name: Jennings, John T.
name: Purcell, Matthew F.
name: Austin, Andy D.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Triozidae
Aacanthocnema
Aacanthocnema dobsoni

description: Aacanthocnema dobsoni (Froggatt)
Figs 19–28, 37–39, 136; Tables 1–8
Trioza dobsoni Froggatt, 1903: 331 –332, pl. iv fig. 11, pl. v figs 11–15. Aacanthocnema dobsoni (Froggatt), Tuthill and Taylor, 1955: 253.
Types. AUSTRALIA, Tasmania: Holotype: 3 (slide) [fore wing, hind leg, parameres, aedeagus] Kempton, 9/01 (Lea), Trioza dobsoni TYPE W.W.F., body in spirit K.L.T. (ANIC).
Other material examined. AUSTRALIA, South Australia: from Allocasuarina verticillata: 13 3, 13 Ƥ (slide), 181 3, 312 Ƥ, 5 nymphs (dried) Adelaide [Urrbrae] (WINC); 88 3, 132 Ƥ, 2 nymphs, Adelaide, Seaview Downs (WINC); 25 3, 36 Ƥ, 2 nymphs (dried) 10 km N Ardrossan (WINC); 1 nymph (dried), 8 3, 5 Ƥ 18 km S Burra (WINC); 9 3, 10 Ƥ (dried) 1 km S Callington (WINC); 28 3, 41 Ƥ (dried) Dawesley-Kanmantoo (WINC); 2 Ƥ (dried) 4.2 km S Edithburgh (WINC); 6 3, 4 Ƥ (dried) 8.8 km SW Edithburgh (WINC); 9 3 17 Ƥ S Edithburgh, coast (WINC); 1 3 S Edithburgh, wind-farm (WINC); 1 3, 2 Ƥ Hindmarsh Is. (WINC); 56 3, 57 Ƥ, 2 nymphs KI, Baudin CP (WINC); 10 3, 6 Ƥ (dried) KI, Harveys Return (WINC); 2 3, 1 Ƥ KI, Muston Lookout (WINC); 1 Ƥ KI, E Stokes Bay (WINC); 17 3, 6 Ƥ, 2 nymphs KI, Vivonne Bay (WINC); 2 3, 2 Ƥ KI, West Bay Rd. (WINC); 2 Ƥ KI, West Bay (WINC); 1 3, 1 Ƥ KI, 3 km S Western R. (WINC); 5 3, 3 Ƥ 2 km S Western R. (WINC); 1 3, 2 Ƥ Willoughby Rd (WINC); 1 3, 1 Ƥ (dried) 6 km N Meadows (WINC); 13 (slide), 23, 3Ƥ, 4 nymphs (dried) 3 km E Modbury (ANIC); 25 3 37 Ƥ, 2 nymphs (dried) 2 km E Mt Barker (WINC); 6 3, 20 Ƥ 3.5 km E Mt Barker (WINC); 34 3, 28 Ƥ, 1 nymph (dried) 7 km E Mt Barker (WINC); 17 3, 27 Ƥ Mt Barker-Murray Bridge (WINC); 76 3, 89 Ƥ, 2 nymphs (dried), 6 3 4 Ƥ 15 km E Mt Pleasant (WINC); 7 3, 5 Ƥ, 1 nymph (dried), 23 3, 27 Ƥ Mt Barker summit (WINC); 3 3, 3 Ƥ, 6 nymphs 5 km E Mt Torrens (WINC); 90 3, 73 Ƥ, 6 nymphs Myponga-Yankalilla Rd. (WINC); 3 Ƥ (dried), 1 Ƥ, 3 km W Port Giles (WINC); 2 3 5 km WSW Pt Giles (WINC); 3 3, 4 Ƥ (dried), 7 3, 2 Ƥ Spring Gully CP (WINC); 8 3, 8 Ƥ (slide), 28 3, 29 Ƥ, 1 km N Strathalbyn (WINC); 13, 13Ƥ (dried), Teatree Gully (ANIC); 7 3, 6 Ƥ 10 km N Victor Harbor (WINC); 7 Ƥ (dried), 2 Ƥ Wool Bay (WINC) 2 3, 1 Ƥ 2 km SW Wool Bay (WINC); 2 Ƥ 1 km W Wool Bay (WINC); from A. leuhmannii: 13 (dried) Adelaide (WINC); from A. torulosa: 1 3 Burra (WINC); from C. cristata: 2Ƥ (dried), Adelaide (WINC); from C. cunninghamiana: 13 (dried) Adelaide (WINC); from Casuarina: 5 nymphs (2 slides), 33, 6 nymphs (dried) Largs Bay (WINC); 7 nymphs (1 slide) Mitcham (WINC). Tasmania: from Casuarina verticillata: 23 (slide), 2 3, 8 Ƥ, 1 nymph (dried) Domain, Hobart (ANIC); 1 3, 1 Ƥ, 1 nymph (slide), 1 3, 4 Ƥ, 1 nymph (dried) Hobart (MHNG); 1Ƥ (dried), Kempton (ANIC); 23, 7Ƥ, 1 nymph (dried) Midway Pt (ANIC); 1 3, 2 nymphs (2 slides) 2 km NW Seven Mile Beach (ANIC); 2 3, 2 Ƥ, 2 nymphs (1 slide) Seven Mile Beach (ANIC); from Casuarina: 1 3 (slide) 2 Ƥ (dried) Midway Pt (ANIC). Australian Capital Territory: nymphs (dried), Mt Ainslie (ANIC); 4 3, 4 Ƥ Mt Ainslie (WINC); 23, 2Ƥ (dried) Mt Madura (ANIC); 1Ƥ (dried) Red Hill (ANIC).
Description. Adult (Figs 19–25). Colour: Male: general colour pale cream to ochraceous with brown to dark brown markings. Vertex pale with a pair of dark brown longitudinal submedial stripes; genal processes pale merging to dark brown apices; antennal segments 1–2 ochraceous to brown; segment 3 darker apically; segments 4–10 dark brown to black; pronotum pale with a pair of dark brown to black broad longitudinal submedial markings; mesopraescutum with a pair of broad longitudinal brown to dark brown stripes, suffused anteriorly; mesoscutum with two pairs of brown to dark brown suffused longitudinal submedial stripes; mesoscutellum with brown medial suffusion; wings clear; legs with dorsal brown infuscation; fore- and mid-tarsi dark brown to black; hind basitarsi ochraceous, distal segment of hind tarsi dark brown to black; abdominal tergites dark brown to black; anterior face of proctiger pale laterally; subgenital plate ochraceous to brown; parameres with dark margins and apices; proximal segment of aedeagus brown, distal segment pale. Female: As for male, except with paler markings; vertex with dark infuscation on anterior margin and a pair of brown markings in vicinity of fovea; proctiger ochraceous merging to dark brown around circum-anal pore ring and at apex; subgenital plate with dark proximal brown infuscation.
Structure: measurements and ratios as in Tables 1–5. Antennae short, 1.09–1.44 times width of head, genal processes elongate, 0.64–0.88 times length of vertex, conical, apices separated, little-divergent; anterior margin of vertex rounded from dorsal aspect, delineated from genal processes by prominent ridge; vertex with weak medial suture; pronotum with moderate anterior, medial node; thorax weakly arched, head wider than pronotum, and little wider than mesoscutum; fore wings short with broadly rounded apex; Rs short, mostly straight except distally, terminating well short of wing apex; vein M1+2 terminating short of wing apex; cell m1 short, broadly triangular; m1 cell value 0.95–1.18; cell cu1 short triangular; cu1 cell value 1.10–1.40; radular areas thin, elongate in cells m2 and cu1, mostly absent in cell m1 or if present restricted to a few spicules; male terminalia as in Figs 37–38; proctiger long, thin, without lateral expansions; parameres short, broad basally from lateral aspect, strongly incurved towards apices. Female terminalia as in Fig 39; proctiger short broadly rounded, dorso-posterior margin rounded in lateral aspect; subgenital plate short, broadly rounded, triangular from lateral aspect.
Nymph (Figs 26–28): Measurements and ratios as in Tables 6–7. Body brown with dark brown markings. Eyes dark brown; head with submedial dark brown markings posteriorly; thorax with dark brown submedial spots anteriorly, meso-and metathoracic depressions dark brown to black with irregular dark brown markings between them, and posteriorly (together forming an irregular submedial stripe); fore wing pads with a longitudinal dark brown infuscation; caudal plate with dark brown infuscation laterally and delineating margins of abdominal tergites. Body elongate; anterior margin of head angulate (angular anterior to eyes and medially); dorsum of body with a distinct medial longitudinal ridge; caudal plate triangular with hind margin pointed.
Distribution. Recorded from Adelaide and environs, Fleurieu Peninsula, Yorke Peninsula and Kangaroo Island in southern South Australia, Canberra in the Australian Capital Territory, and Hobart and environs in Tasmania (Fig. 136).
Host plant. Recorded from Allocasuarina verticillata (Lam.) L.Johnson (drooping sheoak). Allocasuarina verticillata occurs as a 4–10 m tree in grassy woodland to rocky sea-coasts and dry rocky hills and ridges inland, from central New South Wales, Victoria, northern and eastern Tasmania, and southern South Australia, including Yorke and Eyre Peninsulas and Kangaroo Island (Wilson & Johnson 1989). Note that Casuarina stricta and C. quadrivalvis (as cited on early labels) are junior synonyms of A. verticillata. Allocasuarina luehmannii (Miq.) L. Johnson, C. cunninghamiana Miq. and A. cristata Miq. are unlikely hosts: where these hosts were recorded (see label data), trees were ornamentals in close proximity in an arboretum. In each case very few insect specimens were collected, yet they were abundant on neighbouring trees of A. verticillata (GST, personal observation).
Comments. Froggatt (1903) incorrectly cited the host plant of this species as Eucalyptus amygdalina Labill. It is probable also that his description of the nymph and illustrations of the wing and galled foliage are of Schedotrioza tasmaniensis (Froggatt). Morgan (1984) mis-identified A. dobsoni as A. casuarinae: the fore wing illustrated is without infuscation along wing veins, and the localities cited (Adelaide Plains, Mt Lofty Ranges and Kangaroo Island) and host (C. stricta = junior synonym of A. verticillata) are consistent for this species. Meiotic karyotypes and the structure of the testes of Aa. dobsoni were examined in Maryańska-Nadachowska et al. (2001). They exhibited a male diploid karyotype of 2n=25 (24 + X) which is consistent with the majority of the Psylloidea and most likely represents the ancestral condition (Maryańska-Nadachowska et al. (2001).
Aa. casuarinae + Aa. dobsoni
Aa. huegelianae + Aa. luehmannii
Aa. torulosae
Ac. acutivalvis +
Ac. campestris + Ac. diminutae + Ac. muellerianae
Ac. tasmanica
Ac. verticillatae
continued.
Species A. littoralis (?) A. luehmannii A. muelleriana A. torulosa A. verticillata Aa. burckhardti + Aa. casuarinae
Aa. dobsoni + Aa. huegelianae
Aa. luehmannii +
Aa. torulosae + Ac. acutivalvis
Ac. campestris
Ac. diminutae
Ac. muellerianae + Ac. tasmanica +
Ac. verticillatae +
Aacanthocnema dobsoni is very close morphologically to Aa. huegelianae, A. luehmannii and Aa. torulosae. Aacanthocnema dobsoni, Aa. huegelianae, and Aa. torulosae lack pigmentation along wing veins and Aa. luehmannii has pigmentation restricted to the anterior half of vein Cu1a. In Aa. dobsoni width of head, length of antennae and corresponding AL:HW ratio is moderate, in Aa. huegelianae head wide and antennae moderately long and corresponding AL:HW ratio low, in Aa. luehmannii head moderately wide, antennae long and AL:HW ratio high, and in Aa. torulosae head narrow, antennae moderately long and AL:HW ratio high; in Aa. dobsoni and Aa. luehmannii length and width of vertex and corresponding VL:VW and VL:HW ratios are moderate, in Aa. huegelianae vertex short and wide with VL:VW and VL:HW ratios very low, and Aa. torulosae vertex moderately long and narrow and corresponding VL:VW and VL:HW ratios high; in Aa. dobsoni and Aa. luehmannii male proctiger elongate and in Aa. huegelianae and Aa. torulosae short and rounded; in Aa. dobsoni, Aa. huegelianae and Aa. torulosae male aedeagus terminates in a moderate bulb and in Aa. luehmannii it is distinctly larger; in Aa. dobsoni and Aa. huegelianae parameres are parallel-sided from lateral aspect and strongly incurved and in Aa. luehmannii and Aa. torulosae parameres have a bulbous base, narrowing to a pointed apex; in Aa. dobsoni and Aa. torulosae female proctiger short with dorso-posterior margin rounded in lateral aspect, and in Aa. huegelianae and A. luehmannii it is short and dorso-posterior margin is angular.
description: Published as part of Taylor, Gary S., Jennings, John T., Purcell, Matthew F. & Austin, Andy D., 2011, A new genus and ten new species of jumping plant lice (Hemiptera: Triozidae) from Allocasuarina (Casuarinaceae) in Australia, pp. 1-45 in Zootaxa 3009 on pages 16-19, DOI: 10.5281/zenodo.278552