﻿Two new species of the mealybug genus Paracoccus from Jiangxi, South China (Hemiptera, Coccomorpha, Pseudococcidae)

﻿Abstract Two new mealybug species, Paracoccusgillianwatsonae Zhang, sp. nov. and P.wui Zhang, sp. nov., collected from Jiangxi, South China, are described and illustrated based on the morphology of adult females. Paracoccusgillianwatsonae is similar to P.burnerae (Brain, 1915), but it differs in having fewer pairs of cerarii, and in lacking both ventral oral collar tubular ducts on the margins of the head and translucent pores on the hind femur. Paracoccuswui resembles P.keralae Williams, 2004 and P.neocarens (Lit, 1992), but it differs in lacking ventral oral collar tubular ducts on the margins of the head and in having multilocular disc-pores usually in double rows at the posterior edges of abdominal segments V and VI. A key to the Paracoccus species found in China is provided.


Introduction
Members of the family Pseudococcidae (commonly known as mealybugs) are small sap-sucking insects.The Pseudococcidae is the second-largest family of scale insects, with about 2047 described species in 261 genera worldwide (García Morales et al. 2016).The mealybug genus Paracoccus was established by Ezzat and McConnell (1956) with Pseudococcus burnerae Brain, 1915 designated as the type species.Currently, the genus includes 94 species (García Morales et al. 2016) and has a wide distribution in temperate and tropical parts of the world (Moghaddam and Esfandiari 2014).However, molecular phylogenetic analyses by Hardy et al. (2008) and Choi and Lee (2022) have indicated that Paracoccus is not monophyletic.Further molecular and morphological studies on this genus are greatly needed.
In China, Chen et al. (2011) first reported the invasive Paracoccus marginatus Williams & Granara de Willink, 1992 from Taiwan; later, this species was found in many places in mainland China, e.g.Fujian (Lin et al. 2019), Guangdong (Ahmed et al. 2015), Hainan (Wang et al. 2018), Jiangxi (Liao et al. 2021), and Yunnan (Wu et al. 2014;Zhang and Wu 2015).In addition, Miller et al. (2014) reported that three Paracoccus species originating from China had been intercepted at U.S. ports of entry between 1995 and 2012: P. burnerae, P. interceptus Lit, 1997, and P. marginatus.Together with the two new species described herein, there are now five Paracoccus species reported from China.
In this study, Paracoccus gillianwatsonae and P. wui, both collected from Jiangxi, South China, are described and illustrated based on the morphology of adult females.A key to the species of Paracoccus reported from China is provided.

Materials and methods
Adult female specimens were slide-mounted using the method described by Borchsenius (1950).The morphological terminology used follows that of Williams (2004).Body measurements are given in millimeters (mm) and measurements of other structures are given in micrometers (µm).Each taxonomic illustration of the adult female is arranged in the usual way for Coccomorpha, with features of the dorsum shown on the left side and those of the venter on the right.Enlargements of some important characters, not drawn to scale, are arranged around the main illustration.The letters and abbreviations used on the illustrations are explained in the legend below each illustration.
Slides of the new species are deposited in the College of Forestry, Jiangxi Agricultural University, Nanchang, China (CFJAU) and the Insect Collection of the Southwest Forestry University, Yunnan, China (SWFU).The slide labels are written in Chinese.Under 'Materials examined', the collection data of each holotype is listed with '/' indicating the positions of the line breaks on the labels.Description.Live adult female (Fig. 1).Body elongate-oval, covered with thin, pale grey, mealy wax and with short, white lateral filaments around posterior body margins; these becoming successively longer on posteriormost four segments, with caudal filaments longest, each about 1/3 as long as maximum body width.
Venter.Setae relatively long and flagellate, longest setae present on medial area of head and posterior abdominal segments, each 62.5-125.0µm long, accompanied by shorter setae, each 20.0-32.5 µm long.Cisanal setae each 50-55 µm long; obanal setae each 45-50 µm long.Trilocular pores similar to those on dorsum, evenly distributed.Multilocular disc-pores (Fig. 2G), each 7-8 µm in diameter, present around vulva in more-or-less single rows at posterior edges of abdominal segments IV-VII, and scattered or in rows at anterior edges of abdominal segments VI-VII, sometimes with 2 pores on abdominal segment III; also sparsely present on margins of posterior abdominal segments, and occasionally in submedial areas of thorax.Oral collar tubular ducts of 2 main sizes present: larger type (Fig. 2A), each 6-7 µm long and about 3.5 µm wide, present on medial areas of abdominal segments III-VII, in marginal groups on all abdominal segments and opposite each anterior coxa; and smaller type (Fig. 2F), each 5-6 µm long and 2.0-2.5 µm wide, present on medial areas of abdominal segments III-VII, also sparsely present in marginal areas together with large ducts, and occasionally present in medial areas of thorax.
Host plant.Pinaceae: Pinus massoniana Lamb.Distribution.China (Jiangxi).Remarks.Paracoccus gillianwatsonae sp.nov. is similar to P. burnerae (Brain, 1915) (morphological characteristics of P. burnerae based on the redescription and illustration by Williams (2004)) in having ventral multilocular disc-pores in single rows at the posterior edges of abdominal segments IV and V; it differs from the latter (character states of P. burnerae given in parentheses) by having: (i) ventral oral collar tubular ducts absent from margins of the head (present); (ii) cerarii numbering fewer than 18 pairs (18 pairs); and (iii) translucent pores absent from hind femur (present).Etymology.The species is named after Dr San-an Wu (Beijing Forestry University, Beijing, China), who has made important contributions to the study of Chinese scale insects and has selflessly helped the first author.

Paracoccus wui
Description.Live adult female (Fig. 3).Body of mature adult female elongate-oval, covered with white, mealy wax; posterior of body with a short, white ovisac formed of tangled wax filaments.
Dorsum.Setae (Fig. 4K) stout with flagellate tips, sometimes bifurcate; larger setae, each 42.5-62.5µm long and sometimes with 1 or 2 trilocular pores near setal base, and shorter setae, each 17.5-37.5µm long.Trilocular pores (Fig. 4C), each 3-4 µm wide, evenly distributed.Multilocular disc-pores absent.Oral rim tubular ducts (Fig. 4L) very few, totaling 1-8 in available specimens, each about 9 µm long and 4-5 µm wide, with rim 8-9 µm in diameter, mainly present medially, submedially or submarginally on thorax and anterior abdominal segments, sometimes singly next to abdominal cerarii C 11 , C 15 and C 17 , ducts usually absent from medially and submedially areas of abdominal segments IV-VIII.Oral collar tubular ducts usually absent from dorsum, occasionally 1 type of duct, similar to large type of oral collar tubular ducts on venter, singly present marginally or submarginally on thorax, or abdominal segment I, or abdominal segment IV. Venter.Setae (Fig. 4A) relatively long and flagellate, longest setae present on medial area of head and posterior abdominal segments, each 100-138 µm long, and shorter setae, each 30.0-62.5 µm long.Cisanal setae each 100-113 µm long; obanal setae each 95-105 µm long.Trilocular pores similar to those on dorsum, evenly distributed.Multilocular disc-pores (Fig. 4H), each 7-8 µm in diameter, present around vulva, usually in double rows at posterior edges of abdominal segments V-VII, and in single or double rows at the posterior edge of abdominal segment IV; others distributed at anterior edges of abdominal segments V-VII; in addition, a few pores located on submargins of abdominal segments and sometimes also present on abdominal segment III; also scattered pores present on medial and submedial areas of thorax.Oral collar tubular ducts of 2 main sizes present: larger type (Fig. 4B), each about 8 µm long and 3.5-4.0µm wide, present mainly on medial areas of abdominal segments III-VII, in marginal groups on thorax and abdomen, also opposite each anterior coxa; and smaller type (Fig. 4G), each about 6 µm long and 2.5-3.0 µm wide, present mainly on medial areas of abdominal segments II-VII, also sparsely present in marginal areas together with large ducts, and occasionally in medial areas of thorax.
Remarks.Paracoccus wui sp.nov. is similar to P. keralae Williams, 2004 in having only a few dorsal oral rim tubular ducts; it differs from the latter (character states of P. keralae given in parentheses) by having: (i) ventral oral collar tubular ducts absent from margins of the head (present); (ii) multilocular discpores usually in double rows at posterior edges of abdominal segments V and VI (in single rows); and (iii) larger discoidal pores usually each wider than a trilocular pore (narrower than a trilocular pore).
Paracoccus wui also resembles P. neocarens (Lit, 1992) (based on the redescription and illustration by Williams (2004)) in possessing some large discoidal pores and a reduced number of dorsal oral rim tubular ducts; it differs from the latter (character states of P. neocarens in parentheses) in having: (i) ventral oral collar tubular ducts absent from margins of the head (present between antennal bases); and (ii) multilocular disc-pores usually in double rows at posterior edges of abdominal segments V and VI (in single rows).

Figure 2 .
Figure 2. Adult female of Paracoccus gillianwatsonae Zhang, sp.nov.A large-type oral collar tubular duct B trilocular pore C discoidal pore D hind coxa E hind tibia F small-type oral collar tubular duct G multilocular disc-pore H anal lobe cerarius (C 18 ) I dorsal seta J oral rim tubular duct.

Figure 4 .
Figure 4. Adult female of Paracoccus wui Zhang, sp.nov.A ventral seta B large-type oral collar tubular duct C trilocular pore D discoidal pores E hind coxa F hind tibia G small-type oral collar tubular duct H multilocular disc-pore I anal lobe cerarius (C 18 ) J cerarius on abdomen K dorsal seta L oral rim tubular duct.