Discochiton

Chris J. Hodgson & Douglas J. Williams, 2018, Revision of the soft scale genus Paralecanium (Hemiptera: Coccomorpha: Coccidae) with the introduction of three new genera and twenty new species, Zootaxa 4443 (1), pp. 1-162 : 16

DISCOCHITON Hodgson & Williams gen. n.

Type species: Paralecanium expansum Green.

Generic diagnosis. 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.

Name derivation. The name Discochiton is composed of disco - from the Greek diskos, a flat, circular plate (describing the flat, round shape of members of this genus), and - chiton, Greek for garment, a term sometimes used for scale insects referring to their test. The genus name is neuter.

Discochiton currently includes 21 species, all from India, the rest of southern Asia and Australasia; they can be separated using the following key.