﻿Melanasterasinica He & Burckhardt, sp. nov., a new psylloid species (Hemiptera, Psylloidea, Liviidae) from China developing on Grewia sp. (Malvaceae)

﻿Abstract Melanasterasinica He & Burckhardt, sp. nov., a new psylloid species developing on Grewia sp., is described from Hainan, China. It is the first Melanastera species reported from Asia and China, and the second species from the Old World. While New World species of Melanastera are mostly associated with the plant families Melastomataceae and Annonaceae, the two Old World species develop on the malvaceous Grewia, a host otherwise used in psylloids by two Haplaphalara species. The new species is described, diagnosed and illustrated, and its host plant and biogeographic ranges are discussed.


Introduction
Jumping plant lice or psylloids constitute the superfamily Psylloidea, with slightly over 4000 species worldwide (Burckhardt et al. 2023).They are characterised by narrow host ranges mostly associated with eudicots and magnoliids, while hosts from the monocots and conifers are rare.In addition, related psylloid species tend to develop on related hosts (Hodkinson and Bird 2000;Burckhardt 2005aBurckhardt , 2005b;;Burckhardt et al. 2014;Ouvrard et al. 2015).Ouvrard et al. (2015) conducted an analysis of the host patterns of psylloids worldwide and found that psylloid hosts are not evenly distributed across angiosperms.Instead, they identified particular plant taxa that are preferred hosts for psylloids.The Malvaceae is such a family, ranking as the 9 th most important host taxon while it constitutes only the 12 th largest plant family worldwide.Apart from a single species of Triozidae, Bactericera lavaterae (Van Duzee, 1924) (Burckhardt and Lauterer 1997), Malvaceae hosts all the members of the subfamily Carsidarinae (Carsidaridae) (Hollis 1987) and many species of the tribe Paurocephalini (Liviidae, Liviinae) (Burckhardt et al. 2023).Of the Paurocephalini, all of the seven recognised genera include members associated with Malvaceae.Malvaceae, while only a few species of Melanastera and Paurocephala are associated with this family (Burckhardt et al. 2023;Serbina et al. in press).
Recently, an undescribed Melanastera species was discovered on the malvaceous genus Grewia in China.Melanastera currently comprises more than 60 extant species in the New World, many of which develop on Melastomataceae and Annonaceae (Burckhardt et al. 2023;Serbina et al. in press).In the Old World, the genus is represented only by a single Afrotropical species, also associated with Grewia (Burckhardt et al. 2023).
Here, we describe Melanastera sinica He & Burckhardt, sp. nov., which represents the first record of the genus from China and Asia.Morphological information and illustrations are provided for adults and fifth instar immatures.

Material and methods
Material was examined from the Entomological Museum of the China Agricultural University, Beijing, China (CAU) and the Naturhistorisches Museum, Basel, Switzerland (NHMB).
The morphological terminology accords with Burckhardt et al. (2023) and Serbina et al. (in press).For examining morphological structures under the compound microscope, the whole insect was cleared in a hot potassium hydroxide (KOH) solution for ten minutes, washed in distilled water and then mounted on a slide in glycerine.Measurements were taken from slide-mounted specimens.Photos were taken with a Nikon SMZ18 microscope (Tokyo, Japan) attached to a Cannon 7D camera (Tokyo, Japan).Helicon Focus version 5.3 (Helicon Soft Ltd., Kharkiv, Ukraine) was used for image stacking.Line drawings were made using an Olympus BX41 microscope.Photoshop 2020 (Adobe Systems Inc., USA) was used to edit photos including adjustments of background colour and cropping without modifying any characters of specimens.The concept of host plants adopted here is that of Burckhardt et al. (2014).The nomenclature of plants accords with POWO (2024).Diagnosis.Adult.Body yellowish brown with small dark brown dots; forewing with each a broad medial and subapical light brown band and small, dark brown irregular spots.Metatibia with 3+4 grouped apical metatibial spurs separated by five unsclerotised bristle-like setae anteriorly.Forewing oval, widest in apical third; pterostigma long, strongly widening to middle; surface spinules present in all cells, covering membrane up to the veins; irregularly spaced to form groups of 5-6 spinules.Male proctiger weakly expanded posteriorly.Paramere, in lateral view, subrectangular with antero-apical sclerotised tooth.Aedeagus two-segmented; distal segment lacking ventral process.Female proctiger with relatively straight dorsal margin; apex obliquely truncate.Circumanal ring cruciform.-Fifth instar immature.Antenna 10-segmented.Forewing pad with 5 marginal subacute sectasetae.Tarsal arolium narrowly lamellar, widening to apex which is rounded; about twice as long as claws.Caudal plate with anterior margin distant from anterior margin of extra pore fields; with 2 lateral sectasetae on either side near fore margin, and three pointed sectasetae on either side of circumanal ring dorsally.

Taxonomy
Description.Adult.Colouration.Body (Fig. 1A, B) yellowish brown.Head and thorax covered with sparse small brown dots.Antenna yellow to yellowish brown, with apices of segments IV-IX and entire segment X dark brown to black.Femora with brown spots.Forewing yellowish with light brown pattern consisting of each a broad medial and subapical band and small, brown irregular spots, veins pale yellow.
Structure.Head, in lateral view (Fig. 1B), inclined at 45° from longitudinal body axis; in dorsal view (Fig. 1A), about as wide as mesoscutum.Vertex (Fig. 2A) subrectangular, about half as long as wide; surface with fine microsculpture and microscopical setae; median suture developed; posterior margin weakly concave.Genae weakly rounded, with each a pair of long setae on either side of frons (Fig. 2A).Frons relatively large, triangular.Eyes hemisphaerical.Antenna (Fig. 2B) 1.7-1.8times as long as head width, with a single, large subapical rhinarium on each of segments IV, VI, VIII and IX; relative length of flagellar segments as 1.0: 0.5: 0.5: 0.5: 0.6: 0.6: 0.5: 0.4; relative length of segment 10 and terminal setae as 1.0: 1.3: 1.1.Clypeus flattened, in ventral view almost triangular.Thorax distinctly arched, with fine microsculpture; mesoscutellum swollen; metapostnotum with small subacute, laterally compressed tooth.Metacoxa with relatively short horn-shaped, blunt meracanthus; metatibia 1.0 times as long as head width, slender, weakly expanded apically; with 3+4 grouped apical metatibial spurs separated by five unsclerotised bristle-like setae anteriorly.Forewing (Fig. 2C) 2.7-3.1 times as long as head width, 1.6-1.8times as long as wide, oval, widest in apical third; wing apex in the middle of cell r 2 ; veins densely clothed in conspicuous setae; vein C+Sc straight in basal two thirds, strongly bent in apical third; pterostigma long, strongly widening to middle; vein Rs relatively straight in the middle, curved in a 30° angle to costal margin apically; vein M weakly, irregularly curved; veins M 1+2 and M 3+4 slightly shorter than M; vein Cu shorter than M+Cu; vein Cu 1a evenly curved; vein Cu 1b straight, slightly shorter than Cu; surface spinules present in all cells, covering membrane up to the veins, along veins slightly finer; irregularly spaced to form groups of 5-6 spinules.Hindwing (Fig. 2D) slightly shorter than forewing, with indistinctly grouped costal setae.Visible abdominal tergites III-V with a tubercular bump in the middle in both sexes.
Terminalia (Fig. 2E-G).Male proctiger (Fig. 2E) 1.2-1.3times as long as head width, broad with posterior margin produced; in lateral view, widest in basal third.Subgenital plate (Fig. 2E) subglobular, weakly irregularly curved dorsally.Paramere (Fig. 2E, F), in lateral view, subrectangular with antero-apical, partly sclerotised tooth-like process; posterior margin weakly sinuate; outer and inner face covered in long setae in apical half, denser on inner face and along apical and posterior margins.Aedeagus (Fig. 2E) two-segmented; distal segment, in lateral view, tubular and slightly angular postero-apically, lacking ventral process; sclerotised end tube of ductus ejaculatorius moderately long, relatively straight.-Female terminalia (Fig. 2G) cuneate, moderately long.Proctiger 0.4 times as long as head width; in lateral view, dorsal margin, distal to circumanal ring, almost straight; with a transverse row of long setae in the middle and a lateral longitudinal row of long setae on either side in apical third; apex, in lateral view, obliquely truncate, apex slightly upturned.Circumanal ring 0.4 times as long as proctiger; in dorsal view, cruciform.Subgenital plate 0.6 times as long as proctiger; irregularly narrowing to pointed apex, in lateral view; beset with long setae in apical two thirds.
Etymology.From the Latin adjective sinicus = Chinese, referring to the unexpected discovery of this mostly American genus in China.
Comments.Serbina et al. (in press) defined several species groups within Melanastera mostly on the basis of morphological characters of adults.Melanastera sinica is a member of the curtisetosa-group for the absence of a ventral process on the distal segment of the aedeagus.The curtisetosa-group is composed of four species from Brazil associated with Asteraceae (confirmed or likely hosts) and M. pilosa (Burckhardt et al. 2006) from Kenya and Tanzania, developing on Grewia bicolor Juss.(Malvaceae) (confirmed).Melanastera sinica differs from the four Brazilian species in the forewing with a much more expanded dark pattern, which is slightly expanding towards the apex (versus parallel-sided) and bears a broad (versus narrow) pterostigma, in the broad subrectangular paramere (versus narrow, lamellar), the 10-segmented antenna in the last instar immature (versus 9-segmented), and the host association with Malvaceae (versus Asteraceae).From the African M. pilosa with which it shares the expanded dark forewing pattern, the 10-segmented antenna in the last instar immature and the host genus Grewia, it differs in the broader paramere, the absence of long setae on the body and forewing, the broad (versus narrow) pterostigma, the broader paramere (versus narrower), and the apically broader and obliquely truncate (versus slender and subacute) female proctiger (Burckhardt et al. 2006).Burckhardt et al. (2023) suggested that, within Liviinae, new species are more likely to be discovered among the tropical Paurocephalini rather than among its sister group, the predominantly north-temperate Liviini.The discovery of Melanastera sinica in tropical Hainan supports this notion.Melanastera is primarily found in the Neotropical region (Serbina et al. in press), with only a single species known from the Old World so far, viz.M. pilosa (Burckhardt et al. 2006).Melanastera sinica represents the second species from the Old World and the first from Asia.The presence of an expanded dark pattern on the forewing in the adults and 10-segmented antennae in the last instar immatures, shared by the two Old World species, suggests a putative sister group relationship of M. pilosa and M. sinica.The two species also share the malvaceous Grewia as the host, representing a family absent among the hosts of the New World Melanastera species.

Figure 1 .
Figure 1.Habitus of adults of Melanastera sinica He & Burckhardt, sp.nov.A dorsal view B lateral view.Scale bars: 1.0 mm.