A new species of Diaspididae, Megacanthaspisguiyangensis (Hemiptera, Coccomorpha) from China

Abstract A new species of armoured scale insect, Megacanthaspisguiyangensissp. nov. is described and illustrated. The new species is morphologically similar to M.hangzhouensis. Megacanthaspisguiyangenis infests leaves of Oligostachyumlubricum in China. A key to all eight species of Megacanthaspis now known is provided.


Introduction
Armoured scale insects (Hemiptera: Coccomorpha: Diaspididae), are the largest family of the Coccoidea, and have a worldwide distribution, including 426 genera and 2624 species currently identified (García Morales et al. 2016). The morphology of adult females is extremely reduced: no legs, antennae reduced to unsegmented tubercles, head, thorax and abdomen are fused, and these adults are wingless (Balachowsky 1948;Takagi 1993;Andersen et al. 2010;Henderson 2011).
The genus Megacanthaspis Takagi, 1961 belongs to the tribe Diaspidini. The genus was originally established by Takagi (1961) with Megacanthaspis actinodaphnes Takagi, 1961 designated as the type species. The genus is currently composed of seven species (García Morales et al. 2016).
The genus Megacanthaspis is distributed in China, Japan, and Nepal (García Morales et al. 2016). Takagi (1961) collected the type species of this genus in Japan. Later he described another species, M. litseae, from Taiwan, China (Takagi, 1970), and added two new species (M. langtangana and M. leucaspis) from Japan (Takagi, 1981). Takagi (1981) also transferred the species Nanmuaspis phoebia Tang, collected in China (Tang, 1977), into Megacanthaspis. Most recently Wei (2012) recorded two new species of this genus (M. hangzhouensis and M. hainanensis) from China.
A new species of Megacanthaspis was discovered in China and is described and illustrated in this work. This discovery raises the number of species recorded in the genus to eight, five of which have been reported from China. A key to all species of the genus Megacanthaspis is provided.

Materials and methods
Samples of plants infested by the new species described in this study were collected in Guiyang City (Guizhou Province, China). Permanent slide mounts of adult females from the samples collected were slide-mounted using the protocol described by Henderson (2011).
Illustrations of adult female of the new species were drawn from the slide-mounted specimens, showing an overview of the dorsum on the left side and the venter on the right; enlarged details of the significant features are illustrated but not drawn in direct proportion to each other.

Type species. Megacanthaspis actinodaphnes Takagi by monotype and original designation.
Generic diagnosis. Adult female. Body elongate and slender, with metathorax and free abdominal segments not strongly produced; derm membranous. Each antenna with a long seta. Anterior spiracles with disc pores, and posterior spiracles of some species also with disc pores. Gland tubercles present caudad of anterior spiracles, laterocaudad of posterior spiracles and submarginally on 1-3 anterior abdominal segments. Pygidium rounded along posterior margin, all species without lobes, some species with a marginal series of serrate processes or plates. Marginal gland spines pre-sent on the abdomen, each with one or more microducts. Dorsal macroducts present on abdomen and arranged in segmental rows but not in a well-defined series. Ventral ducts are the same size or smaller than dorsal ducts. Anal opening situated in the centre of pygidium. Perivulvar pores with five groups or connected to form an arc.
Remarks. The genus Megacanthaspis, like other groups such as Thysanaspis and Pygalataspis, has non-glanduliferous plates that are well developed but does not have distinct lobes. Thysanaspis and Pygalataspis have no gland spines. Members of the genera Megacanthaspis, Kuwanaspis, and Nikkoaspis all have plates and gland spines. Paratypes: 59 specimens, same data as holotype (at, 1 slide with 1 adult female, 1 slide with 2 adult females, 1 slide with 3 adult females, 4 slides each with 4 adult females, 5 slides each with 5 adult females, 2 slides each with 6 adult females (NWAFU).

Megacanthaspis guiyangensis
Description. Adult female. (Figs 1-8) Body outline oblong fusiform, with indistinct segmentation. Each antenna with a long seta and a tubercle. Anterior and posterior spiracles without disc pores. The pygidium with sharp marginal processes on abdominal segments VII-VIII: 2 on each side of abdominal segment VII, 2 on abdominal segment VIII between the marginal gland spines (Fig. 8). Marginal gland spines each associated with one microduct, present on abdominal segments V-VIII: one pair, widely separated, on abdominal segment VIII and two pairs on abdominal segments V-VII. Some individuals have one pair of marginal gland spines on abdominal segment IV. Gland tubercles absent. Dorsal macroducts arranged in irregular rows on abdominal segments II-VIII and numbering approximately 23-50 on each side; Marginal macroducts arranged one on each side of abdominal segment VII, and absent on abdominal segment VIII between the gland spines. Ventral microducts smaller than dorsal macroducts, scattered loosely on the cephalothorax and abdomen. Anus rounded, located near the centre of the pygidium. Five groups of perivulvar pores form arcs: 3-5 in the median group, 5-8 in each laterocephalic group, and 4-8 in each laterocaudal group.
Diagnosis. Megacanthaspis guiyangensis sp. nov. resembles M. hangzhouensis (Wei & Feng, 2012) in body outline, absence of gland tubercles and with 1 microduct on each of the marginal gland spines. The important differences between the pygidia of the two species are shown in Table 1.