Valid Names Results
Discochiton Hodgson & Williams, 2018 (
Coccidae)
Nomenclatural History
- Discochiton
Hodgson & Williams
2018: 16.
Type species: Paralecanium expansum Green
by original designation
.
accepted valid name
Remarks
- Structure: Adult females showing most of the character-states typical of Paralecanium but with following combination of characters. Test glassy, probably composed of a series of polygonal plates in 7 or 8 longitudinal lines. Body usually almost round to broadest across abdomen, usually reasonably symmetrical. Dorsum becoming sclerotised at maturity; many specimens with rather elongate areolations submarginally, the long axis of each areolation lying parallel to margin, and with less elongate areolations more medially. Marginal radial lines indistinct, only indicated by arrangement of dorsal setae and pores, with generally 13 around anterior margin of head, and each side with 5 between stigmatic clefts and usually 13 on abdomen. Stigmatic rays present. Abdominal clear areas probably always present. Dorsal setae variable in shape, occasionally of two distinct sizes, with those located submarginally and submedially each situated in a membranous area of derm. Preopercular pores present in groups around at least one abdominal clear area. Dorsum with 2 or 3 other pore types, all generally sparse, including a small simple pore and a smaller pore, perhaps with a microduct. Pores and setae forming a polygonal pattern similar to that of the test. Anal plates variable in shape, usually longer than their combined width. Anogenital fold with 2–6 pairs of setae on anterior margin, each lateral margin with 1 anteriorly and another posteriorly. Marginal ornamentation variable but usually consisting of castellations or corrugations with short radial lines. Marginal setae fan-shaped, each almost round to broadly oval (but spinose in D. pseudexpansum). Stigmatic clefts deep and sclerotised, each cleft with 3–6 stigmatic spines in a transverse line along its base. Transverse bands of multilocular disc-pores present medially on abdominal segments V, VI and VII or just on VI and VII. Anterior spiracular disc-pore bands complete but posterior bands almost invariably with a gap without pores medially. Ventral microducts few. Ventral setae few. Antennae each 6 segmented but almost invariably with at least apical 3 segments (IV–VI) fused and with some setose setae missing. Spiracles usually rather small but sometimes significantly larger. Legs usually absent or reduced to leg stumps but fully-developed legs present on two species. (Hodgson & Williams, 2018)
The first-instar nymphs (crawlers) of Discochiton differ from those of Paralecanium in lacking tibial setae, which may be a generic difference. Within Discochiton, the crawlers of D. expansum are very unusual in having 2 similar (large) tarsal digitules on the prothoracic legs. All other first-instar nymphs of known Coccidae have one large digitule and a setose digitule, and all other first-instar nymphs of Discochiton and Paralecanium species seen here had dissimilar digitules. The second/third-instar female specimens of Discochiton species are immediately separable from those of Paralecanium species by the absence of legs in the former but are otherwise very similar.(Hodgson & Williams, 2018)
- Biology: Discochiton currently (2018) includes 21 species, all from India, the rest of southern Asia and Australasia. (Hodgson & Williams, 2018)
- General Remarks: Description and illustration of first-instar, second/third-instar female nymph, second-instar male nymphs in Hodgson & Williams, 2018.
Keys
- HodgsoWi2018: pp.11
(
Adult (F)
)
[Genera in the Paralecanium-group]
Associated References
22 Species
