Tanyscelis 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 : 18-19

Tanyscelis Hardy & Gullan gen. n.

Type species:

Opisthoscelis pisiformis Froggatt 1894b.

Generic diagnosis.

Adult female and associated gall. Galls on leaves and stems; each either globular, hemispherical, conical, mammiform or thorn-like, never pit-like; with orifice usually slit-like, sometimes circular to oblong; if galls on leaves, orifice on either abaxial or adaxial surface, depending on Tanyscelis species, but surface often difficult to determine in mature isobilateral leaves and galls typically opening on same surface on any one leaf. Female attached by mouthparts to internal gall wall opposite to opening, with long hind legs projecting forwards over body or towards gall orifice; body of female fills only part of gall cavity; in some species dorsum often covered with white powdery wax. Body outline ovate to turbinate. Abdomen tapered. Vulva on ventral surface near apex of abdomen between segments VII and VIII. Eyes on dorsum close to margin or a papilliform fleshy protuberance on each side of head in place of eyes. Antennae reduced, with ≤ 3 segments, usually 1-segmented. Pair of broad frontal lobes posteromedial of antennae (possibly absent in Tanyscelis villosigibba ). Oral lobes membranous to sclerotic, sometimes forming large circular pad around mouthparts. Tentorial box with aliform extensions. Fore and midlegs reduced, segmentation indistinct. Hind legs usually positioned on extreme posterior of thorax and often appear to be located on anterior abdomen; elongate, sometimes nearly as long or longer than body; ratio of length of trochanter + femur / length of tibia + tarsus <1; tibia-femur articulation either functional or tibia and femur fused to varying degrees; translucent pores present at least tibia or tibiotarsus; trochanter with 2-6 campaniform sensilla on each surface; claw always highly reduced to absent, claw and tarsal digitules often present but reduced. Anal opening apical or dorsal; anal ring absent or small, without pores and no more than 6 minute setae. Posterior abdominal segments usually without marginal fleshy projections bearing spines (present near anal opening in Tanyscelis verrucula and Tanyscelis pisiformis ). Margin without linear fringe of differentiated setae (though Tanyscelis convexa with submarginal band of staggered spines on venter extending from anterior portion of head to posterior spiracles). Dorsum may be humped, or have large fleshy projections. Derm membranous, sclerotic, or bearing minute papillae. Dorsal setae usually flagellate, minute to very long, 5-220 µm long, sometimes born upon fleshy spines. Cribriform plates and tubular duct clusters absent. Microtubular ducts absent from both body surfaces. Macrotubular ducts with vestibule thin and sclerotic, may be present on dorsum and venter, dorsum only, venter only, or absent. Quinquelocular pores on ventral body surface, sometimes throughout dorsum or confined to dorsal surface of abdomen.

Adult male. Antenna 9-segmented. Abdomen tapered, elongate in some species. Gland pouches and associated setae absent. Detailed description given by Theron (1968). Theron based his description on specimens of two unidentified species collected from Keith, South Australia, ex Eucalyptus fasciculosa , provided to him by HMB. Exactly two species from this host and locality, and collected prior to 1968, are present in the collection of HMB: Opisthoscelis spinosa and Opisthoscelis maculata , here transferred to Tanyscelis .

In contrast, the known adult males of Opisthoscelis have 10-segmented antennae, a non-tappered abdomen, and have gland pouches, each with a pair of gland setae.

First-instar nymph. Anterior margin of head incised at midline. Each spiracle with one trilocular pore next to opening. One submedial longitudinal row of dorsal setae on each side of body. Antennae 3- or 4-segmented, with 4 fleshy setae on apical segment(s). The known first-instar nymphs of Opisthoscelis share all of these states.

Etymology.

The genus name is a Latinised combination of the Greek tany- meaning long (from the word tanyo meaning stretch out) and skelos meaning leg, and refers to the long hind legs of the adult female. Our new name is feminine as for Opisthoscelis , the sister genus of Tanyscelis .