Description of a new species of Saissetia from China (Hemiptera, Coccomorpha, Coccidae)

Abstract The adult female of a new species of soft scale Saissetiapuerensis Zhang & Feng, sp. n. is described and illustrated from the genus Saissetia Deplanche, 1859. This species was collected on Lithocarpusuvariifolius (Hance) in Yunnan province, China. A key is provided to separate adult females of all Saissetia species known from China. A table is provided showing the distribution of Saissetia in various zoogeographical regions throughout the world.


Introduction
Soft scale insects, the third largest family of the Coccoidea, are distributed around the world, and currently include 169 genera and 1183 species (García Morales 2018). Most of them are pests of agricultural and horticultural crops. One species of soft scale, Ericerus pela which provides wax, an important industrial raw material, is considered to be beneficial in industry (Fang and Wang 2012;Henderson and Hodgson 2005).
The genus Saissetia, described by Deplanche in 1859, is a member of the tribe Saissetiini, subfamily Coccinae, and includes 44 species from around the world (Tang 1991;García Morales 2018). Six species of Saissetia have been recorded in China (García Morales 2018).
In this paper, the adult female of a new species Saissetia puerensis Zhang & Feng, sp. n. is described and illustrated. In addition, the genus Saissetia is described and a key is provided to separate the six species of Saissetia currently known from China. A list of Saissetia species throughout the world and their distributions in various zoogeographical regions is presented in Table 1.

Materials and methods
All specimens were collected from Yunnan province in China, and mounted according to the methods described by Hodgson and Henderson (2000). The morphological terminology describing the mounted specimens primarily follows the nomenclature developed by Hodgson (1994). A Nikon compound microscope was used to examine specimens and an Olympus BH-2 stereoscopic microscope was used to draw illustrations from mounted adult female specimens. Measurements of all characters were recorded in micrometers (μm) or millimeters (mm).
Diagnosis. The adult female of S. puerensis can be diagnosed by the combination of the following features: (1) body convex and sclerotized, distinct H-shaped ridge present on dorsum surface; (2) dorsal tubercles present; (3) dorsal tubular ducts absent; (4) dorsal setae tapered; (5) antennae 8 segments; (6) legs well developed, with tibiotarsal articulation and articulation sclerosis; (7) spiracular disc-pores present in a rather broad band 7-8 pores wide; (8) anal plates with a discal seta; (9) ano-genital fold with four or five pairs of setae; (10) four types of ventral tubular ducts: (i) type I present on medial submarginal area and inner and medial submarginal area of posterior abdominal segments, some scattered on inner submarginal area mingling with type II, some on outer submarginal area mingling with type III, (ii) type II present mainly on inner submarginal area, few present on procoxa and mesocoxa, and a few ducts present near antennae and mouthparts, some mingling with type I in medial submarginal area, (iii) type III present on outer broad submarginal area, some ducts present in inner submarginal area, (iv) type IV present on anal cleft and broad submarginal band mingling with t types I, II and III, most present on posterior abdominal segments, few ducts present on mesocoxa; (11) pregenital disc-pores, 10-11 loculi, mainly with ten loculi, abundant around anal opening, some extending in transverse bands on abdominal segments, and some laterad of metacoxa and mesocoxa.
Description. Appearance in life. Pre-reproductive adult female: Body elongateoval, dorsum greenish. Mature adult female: Body oval, dorsum reddish-brown, convex and sclerotized, distinct H-shaped ridge present on dorsum surface.
Type II: inner ductule almost twice as long as outer ductule, inner ductule thinner than outer ductule, but not filamentous, with a well-developed terminal gland; present mainly on inner submarginal area, few present on procoxa and mesocoxa, and a few ducts present near antennae and mouthparts, some mingling with type I in medial submarginal area.
Type III: outer ductule of this type slightly shorter than type I, a filamentous inner ductule without terminal gland; present on outer broad submarginal area, some ducts present in inner submarginal area.
Type IV: inner ductule almost two times as long as outer ductule, a filamentous inner ductule with a ball-shaped terminal gland; present on anal cleft and broad submarginal band mingling with t types I, II, and III, most present on posterior abdominal segments, few ducts present on mesocoxa. Ventral tubular ducts distributed irregularly; a few are scattered near anal cleft, becoming progressively more frequent anteriorly. Submarginal setae present in a single row, each 7.5-14.2 μm long; other ventral setae slender, each 7.9-18.6 μm long, quite sparsely distributed.
Etymology. The species epithet puerensis is a noun in apposition, referring to the place where this new species was collected.

Discussion
This species is considered to be close to Saissetia coffeae (Choi and Lee 2017) and they share some distinct characteristics: 1) more than one type of ventral tubular duct; 2) anal plate with a discal seta; 3) three pairs of setae present along lateral margin; and 4) anal ring subcircular, with four pairs of setae. However, S. puerensis can be distinguished by the possession of the following features (character states of S. coffeae in parenthesis): 1) four types of ventral tubular ducts (three); 2) ventral tubular ducts distributed irregularly, especially on posterior abdominal segments, type I mingling with type II ( regularly); 3) type II not present on medial thorax (present); 4) inner ductule of type II ventral tubular ducts almost twice as long as outer ductule (inner ductule as long as outer ductule); 5) spiracle in a rather broad band 7-8 pores wide (2-3); 6) preopercular pores 14-26 in front of anal plates (5-14); and 7) ano-genital fold with four or five pairs of setae (three).
Lithocarpus uvariifolius (Hance) Rehd is the only plant known to be a host for S. puerensis. Heavy infestations of this pest cause a sooty mold to build up, which reduces photosynthesis and stunts the growth of the plant. L. uvariifolius is only known from China (Wu et al. 1999), and S. puerensis may therefore be restricted to this country. Further studies are required to determine if S. puerensis has other host plants and occurs in other countries. (Table 1) Table 1 is based on information from ScaleNet which has not been published previously. Only S. coffeae, S. miranda, and S. oleae have worldwide distributions. The highest numbers of species are found in the Ethiopian and Neotropical regions, with 50.0% and 43.2% respectively; 40.9% of species occur only in the Ethiopian region and 34.1% only in the Neotropical region. The Nearctic region has fewest species, with only 9.1%.