Tanyscelis megagibba Hardy & Gullan

Hardy, Nate B. & Gullan, Penny J., 2010, Australian gall-inducing scale insects on Eucalyptus: revision of Opisthoscelis Schrader (Coccoidea, Eriococcidae) and descriptions of a new genus and nine new species, ZooKeys 58, pp. 1-74 : 29-30

Tanyscelis megagibba Hardy & Gullan sp. n. Figs 3a16

Gall

(Fig. 3a). Female. On stem. A rounded swelling; gall opening slit-like; base of gall broad, gall surface striated, distal part a narrow truncate cone bearing orifice.

Male. On stem; similar to gall of female but without apical cone; gall opening irregularly shaped.

Adult female

(Figure 16) (n = 19). Body rotund, with 3 or 4 very large dorsal humps, body margin ovate, length 1.4-3.3 mm, greatest width 0.9-ca 3 mm; abdomen appears to be tapered (truncate in all slide-preparations, but clearly tapered in photograph of adult female in life). Eyes each 60-85 µm wide, convex, with base not parallel-sided or perpedicular to body surface. Antennae 1-segmented, 95-125 mm long. Frontal lobes often difficult to detect, each ca 150 µm long, 190 µm wide. Tentorial box 325-450 mm long. Labium 115-150 mm long, 100-110 mm wide. Pump chamber 30-38 µm long, 35-40 µm wide. Spiracles 125-170 mm long, 55-100 mm wide across atrium. Fore and mid legs small sclerotic stubs, 18-45 µm long. Hind leg slender and elongate; coxa 370-430 µm long, trochanter + femur 480-550 µm long, tibia straight, 750-1000 µm long, tarsus 410-540 µm long; translucent pores scattered over both surfaces tibia, plus a few on femur and tarsus; femur-tibia articulation non-functional, base of tibia fixed at obtuse angle to femur; each side of hind trochanter with 3-6 campaniform sensilla; claw and digitules absent. Anal opening 8-20 µm wide, anal ring poorly developed, with ca 6 setae.

Dorsum. Dominated by 3 or 4 large humps. Derm lightly sclerotised, densely beset with minute papillae, these diminishing in size caudad and are replaced by microtrichia on abdomen, cuticle on humps may be more heavily sclerotised than elsewhere. Dorsal setae slender, 7-53 mm long; in transverse row across each abdominal segment, scattered on head and thorax, longest setae on posterior abdominal segments. Macrotubular ducts and microtubular ducts absent. Quinquelocular pores 7-8 µm in diameter, on posterior abdominal segments.

Venter. Oral lobes membranous. Setae as on dorsum, 12-80 mm long, in a transverse row across each abdominal segment, plus a few scattered along margin of head and thorax. Macrotubular ducts absent. Quinquelocular pores similar to those on dorsum, in a transverse row across each abdominal segment plus a few clustered around each spiracle, absent elsewhere.

Material examined.

Holotype (here designated): AUSTRALIA: South Australia: 1 adult female (1.8 mm long, 1.2 mm wide), on slide with 2 other females, holotype closest to data label: ex gall on stem, Eucalyptus microcarpa [original label incorrectly has Eucalyptus odorata ; see Comments below], Aldinga Beach, 2 Oct., 1965, H. M. Brookes, Specimen Index No. 44/65 (ANIC).

Paratypes: AUSTRALIA: South Australia: 2 adult females, on same slide as holotype (ANIC); 6 adult females: ex stem galls, Eucalyptus microcarpa , Aldinga Beach, 9 Jan., 1964, H. M. Brookes, Specimen Index No. 4/64 (ANIC); 10 adult females: same data except 2 Oct., 1965, Specimen Index No. 44/65 (ANIC); 4 adult females: ex galls, Eucalyptus sp., Aldinga Beach, 11 Mar., 1966, HMB (ANIC); 7 adult females: ex galls, Eucalyptus sp., 1.5 km ESE of Moorlands, 6 May, 1980, PJG (ANIC).

Comments.

Adult females of Tanyscelis megagibba are most similar to those of Tanyscelis villosigibba , in the sense that the dorsal surface of both species is dominated by a series of large humps. These are most spectacular in mature females of Tanyscelis megagibba , but lack the dense covering of setae, each born on a raised fleshy base, that is characteristic of the adult females of Tanyscelis villosigibba . Adult females of Tanyscelis villosigibba are also distinctive in having highly convex eyes, with the base of each eye parallel-sided and perpendicular to the body surface, whereas in Tanyscelis megagibba the base of each eye is not parallel-sided. Tanyscelis megagibba is known from only two localities, ca 100 km apart, in South Australia, whereas Tanyscelis villosigibba is known from four localities in Queensland.

The original labels on the slides from two of the three collections of Tanyscelis megagibba made by HMB have the host as Eucalyptus odorata . However, her subsequent notes specify that this was a misidentification and the collections were made from Eucalyptus microcarpa (not Eucalyptus odorata ).

Etymology.

The species name is derived from the Latin word gibber, meaning hump on the back. This species has impressively large dorsal humps. The name is a noun in apposition.