Pseudophacopteron aewagriini Percy & Martoni, 2025

Martoni, Francesco, Tweed, James M. H., Blacket, Mark J. & Percy, Diana M., 2025, An annotated checklist of the psyllids (Hemiptera, Psylloidea) of Norfolk Island with keys to species, new records, and descriptions of two new endemic species, ZooKeys 1238, pp. 297-348 : 297-348

Pseudophacopteron aewagriini Percy & Martoni sp. nov.

Figs 8 , 9 , 10

Type locality.

Norfolk Island, Norfolk Island National Park, Red Road Track, on Alyxia gynopogon on side of track. Dislodged beating host plant onto tray and collected using entomological aspirator.

Type material.

Holotype: Norfolk Island • 1 adult ♂; Norfolk Island National Park, Red Road Track ; 17 Oct. 2022; Francesco Martoni leg.; on Alyxia gynopogon ; sweeping; entire specimen mounted on card triangle, deposited at VAIC. Labels: “ Norfolk Island N. P. / Red Road Track / 17 - Oct- 2022 F. Martoni / On Alyxia gynopogon ” (printed on white card); “ HOLOTYPE ♂ / Pseudophacopteron aewagriini / Percy and Martoni 2025 ” (printed on red card) . Paratypes: Norfolk Island • 5 adult ♂♂, 5 adult ♀♀; same data as the holotype, dissected specimens mounted on microscope slides, deposited at VAIC • 1 adult ♂, 2 adult ♀♀; same data as the holotype, entire specimens mounted on card triangle, deposited at ANIC • 16 adult ♂♂, 18 adult ♀♀; Norfolk Island National Park, Bridle Track ; 15 Oct. 2023; James M. H. Tweed leg.; on Alyxia gynopogon ; entire specimens preserved in ethanol, deposited at VAIC • 2 adult ♂♂, 2 adult ♀♀, same as for preceding; entire specimens preserved in ethanol, deposited at NHMB • ~ 200 immatures; Norfolk Island National Park, Red Road Track car park ; 08 Nov. 2023; James M. H. Tweed leg.; on Alyxia gynopogon ; entire specimens preserved in ethanol, deposited at VAIC • 1 adult ♂, 3 adult ♀♀; Norfolk Island National Park, Forbidden Track ; 20 Feb. 2023; James M. H. Tweed leg.; On Alyxia gynopogon ; entire specimens preserved in ethanol, deposited at VAIC • 3 adult ♂♂; Norfolk Island National Park, Red Road Track ; 15 Oct. 2022; Francesco Martoni leg.; on Alyxia gynopogon ; entire specimens preserved in ethanol, deposited at VAIC • 4 adult ♂♂; Norfolk Island National Park, Palm Glen ; 11 Jul. 2013; Alice Wells leg.; on Alyxia gynopogon ; AW-12-95 ; entire specimens preserved in ethanol, deposited at DMPC • 3 adult ♂♂, 2 adult ♀♀,; Norfolk Island National Park, Palm Glen ; 22 Oct. 2013; Laurence Mound leg.; on Alyxia sp. ; LAM 5815 ; entire specimens preserved in ethanol, deposited at DMPC . All paratypes are labelled as “ PARATYPE ♂ - ♀ / Pseudophacopteron aewagriini / Percy & Martoni 2025 ” (printed on blue card).

Other material examined.

Norfolk Island • ~ 20 immatures; Norfolk Island National Park, Red Road Track ; 14 Mar. 2022; Francesco Martoni leg.; on Alyxia gynopogon ; entire specimens preserved in ethanol, deposited at VAIC . Not included in the type series because they were damaged during a semi-destructive DNA extraction protocol.

Diagnosis.

The shape of the fore wing of P. aewagriini , which is elongate and narrow (> 2.6 × longer than wide), as well as the pigmentation pattern, clearly aligns this taxon with other Pseudophacopteron in the Austro-Pacific region ( Malenovský 2008); the type species, P. tuberculatum Crawford , as well as most other taxa also found on Apocynaceae host plants, have a fore wing that is pyriform and broad (length <2.6 × width) ( Malenovský 2008; Malenovský and Burckhardt 2009; Malenovský et al. 2015). A similar narrow wing morphology to that of P. aewagriini can be observed in some of the African Pseudophacopteron species such as P. nigritulum Malenovský and Burckhardt and P. wagneri Malenovský and Burckhardt ( Malenovský and Burckhardt 2009) , but in these cases the vertex lacks a distinct median ridge, and only P. wagneri is possibly associated with Apocynaceae . See also the Remarks section below.

Description.

Colouration. Adult. Head pale brown. Antennae with segments 1 and 2 brown, segments 3–8 of a very pale brown, and segments 9 and 10 dark brown tending to black. Thorax mostly dark brown but with medial line crossing mesoscutum and mesopraescutum lighter. Legs with dark brown femora and basal part of tibiae, and with pale brown apical part of tibiae and tarsi (Fig. 8 A – D ). Fore wings hyaline, with dark brown pattern covering basal 1 / 3 of wing and reaching wing apex in the basal portion of cell r 2 as a band along posterior wing margin, leaving small transparent areas in cells cu 2, cu 1, m 1 and m 2; dark pattern also covering the proximal part of fore wing, reaching the vein C + Sc, crossing the middle of cell c + sc and the bifurcation of stem R + M + Cu (Figs 8 E, F , 9 A, B ); fore wing veins pale brown or dark brown in areas covered by dark pattern. Hind wing pale to darker brown basally (Fig. 9 B ). Male and female terminalia pale brown to pale yellow. Female proctiger darker on the tip.

Immature (5 th instar). Body uniformly dark yellow-brown (Fig. 8 G ).

Structure. Adult. Body relatively small, 1.5–1.9 mm from anterior margin of vertex to tip of folded wings (males smaller than females) (Fig. 8 A – D ). Head (Figs 8 A – D , 9 D – F, H – J ) in lateral view not deflexed downward and held in same plane as body, wider than thorax but narrower than antennal length, vertex width almost 3 × length, with prominent narrow median ridge and two bulges anteriorly either side of ridge, lateral ocelli raised on small tubercles above the plane of vertex, median epicranial suture reduced. Genae (Fig. 9 E, F ) small, weakly swollen, genal tubercles below toruli small and acute, prominent in lateral profile. Clypeus (Fig. 9 G ) subglobular, terminal proboscis segment short. Antenna (Fig. 9 H ) with ten segments, segment 3 longest with segments 4–8 of subequal length, widening slightly from base to apex, segment 9 slightly shorter and wider apically, while segment 10 very short, <1 / 2 the length of segments 3–8 and ~ 1 / 2 the length of segment 9; a single subapical rhinarium on each of segments 4–9, large, elliptical and fringed by cuticular spines; terminal setae unequal, with longer seta reaching 0.1 mm, shorter seta between 1 / 2–2 / 3 length of longer and approx. as long as segments 9 and 10 combined.

Thorax (Fig. 9 I – K ) moderately arched, mesoscutum with reduced microsculpture and pigmentation in medial depression. Mesotibia with subapical comb of ≤ 6 stout setae. Hind legs (Fig. 9 M – O ) with small, acute and slightly curved meracanthus; metafemur constricted medially, length subequal to metatibia; metatibia without genual spine basally, with an open crown of seven unsclerotised spurs apically and ≤ 12 stout lateral setae more slender than apical spurs; metabasitarsus subglobular, approx. as long as broad, slightly shorter than apical tarsus, with two sclerotised lateral spurs.

Fore wing (Figs 8 E, F , 9 A, B ) elongate, 2.6–2.8 × longer than wide, much wider in apical half, rounded at apex; cell m 1 narrower and more elongate than cell cu 1, vein M approx. as long as vein Rs to the point it meets vein M 1 + 2 and only slightly arched; membrane with dispersed spinules distributed in all cells and with spinule-free bands along veins, radular spinules concentrated into small triangular fields in outer pigmented corners of apical cells cu 1, m 2, m 1, and the adjacent corner of r 2 (Fig. 9 C ).

Male terminalia (Fig. 10 A – C ) with subgenital plate subglobular, dorsal margin slightly sinuate and posteriorly bearing several long stout setae; proctiger relatively slender, cylindrical, in lateral profile straight except apex which is slightly bent posteriorly; parameres simple, shorter than proctiger, in lateral profile parallel sided and more or less straight, apex bluntly rounded and slightly bent posteriorly, inner surface with a weakly produced and marginally sclerotized tooth subapically; outer and inner surface covered with fine setae and a few slightly stouter setae subapically. Distal segment of aedeagus relatively short, apical portion ~ 1 / 3 as long as the distal segment length, somewhat elongate, broadly globular, unhooked but angled downward, apex rounded.

Female terminalia (Fig. 10 D – G ) with proctiger much longer than subgenital plate, narrowing to bluntly acute apex covered in stout setae, anal ring narrowly oval with the outline in profile and dorsal view irregular, composed of a double row of intermittently irregular pores, anal ring length ~ 1 / 3 proctiger length; subgential plate ~ 2 / 3 proctiger length, narrowing to a truncate, weakly incised apex; ovipositor dorsal valvulae triangular, ventral valvulae finely serrate with a series of shallow teeth ventrally.

Immature (5 th instar): body ~ 1.75 × as long as wide, relatively large in size compared to the adult, shape narrowly oval, dorso-ventrally flattened, wing pads not protruding (Fig. 8 G ). Entire margin of head, wing pads and abdomen ringed with longitudinally ridged, truncate marginal setae with apices raggedly uneven (Fig. 8 G ). Antenna short, length ~ 0.32–0.45 × head width, with ~ 7 indistinct subdivisions (rhinaria not clearly visible). Fore wing pads lacking distinct humeral lobes, but with slight anterior bulges. Tarsal arolium shorter than claws, membranous, fan-shaped with unguitractor, claws well developed (Fig. 8 H ). Anus in ventral position (Fig. 8 G ), circumanal ring shallowly V-shaped, antero-posteriorly constricted and slightly sinuous, consisting of a single row of elongate pores (Fig. 8 I ).

Measurements (in mm). Adults (5 ♂♂, 5 ♀♀). Length of body (vertex to terminalia) ♂ 1.01–1.17, ♀ 1.22–1.35; length of body (vertex to apex of folded wings) ♂ 1.55–1.80, ♀ 1.78–1.93; width of head (HW) ♂ 0.37–0.42, ♀ 0.40–0.45; length of antenna (AL) ♂ 0.40–0.44, ♀ 0.47–0.51; longer antennal terminal seta length (T 1) ♂ 0.06–0.09, ♀ 0.07–0.10; shorter antennal terminal seta length (T 2) ♂ 0.03–0.05, ♀ 0.04–0.06; length of antennal segments 9 and 10 together (TS) ♂ 0.05–0.06, ♀ 0.06–0.07; length of fore wing (WL) ♂ 1.27–1.40, ♀ 1.40–1.57; width of fore wing (WW) ♂ 0.45–0.52, ♀ 0.51–0.58; length of line connecting base of vein C + Sc and apex of vein R 1 (CS) ♂ 0.51–0.58, ♀ 0.59–0.65; length of line connecting base of vein C + Sc and costal break (CB) ♂ 0.46–0.52, ♀ 0.51–0.59; length of line connecting the touching point of veins Rs and M 1 + 2 and apex of Rs (a) ♂ 0.17–0.21, ♀ 0.20–0.25; length of line connecting the touching point of veins Rs and M 1 + 2 and apex of M 1 + 2 (b) ♂ 0.41–0.45, ♀ 0.47–0.54; length of line connecting apices of veins Rs and M 1 + 2 (c) ♂ 0.36–0.41, ♀ 0.40–0.48; length of line connecting apices of veins Cu 1 a and Cu 1 b (d) ♂ 0.34–0.38, ♀ 0.38–0.44; length of line connecting base and apex of vein Cu 1 b (e) ♂ 0.12–0.14, ♀ 0.13–0.16; metatibia length (TL) ♂ 0.25–0.31, ♀ 0.28–0.35; male proctiger length (MP) ♂ 0.10; paramere length (PL) ♂ 0.08–0.10; length of distal segment of aedeagus (DL) ♂ 0.08–0.09; female proctiger length (FP) ♀ 0.23–0.27; female subgenital plate length (SL) ♀ 0.14–0.19. Ratios: AL: HW ♂ 1.00–1.19, ♀ 1.13–1.19; T 1: TS ♂ 1.20–1.60, ♀ 1.14–1.17; T 1: T 2 ♂ 1.60–2.00, ♀ 1.50–1.75; WL: HW ♂ 3.28–3.43, ♀ 3.49–3.58; WL: WW ♂ 2.69–2.84, ♀ 2.64–2.80; CB: CS ♂ 0.86–0.91, ♀ 0.86–0.91; a: b ♂ 0.40–0.51, ♀ 0.39–0.52; a: c ♂ 0.45–0.58, ♀ 0.44–0.63; d: e ♂ 2.64–2.83, ♀ 2.56–3.00; TL: HW ♂ 0.68–0.74, ♀ 0.70–0.78; MP: HW ♂ 0.24–0.27; PL: HW ♂ 0.19–0.24; DL: HW ♂ 0.21–0.22; FP: HW ♀ 0.57–0.63; SL: FP ♀ 0.35–0.42.

Immatures (5 th instar, n = 4). Length of body 1.50–1.60; width of body 0.88–0.96; length of antennae 0.17–0.25; width of head 0.54–0.56.

Etymology.

The name epithet uses the Norf’k (local resident language spoken on Norfolk Island) word “ aewagriin ” that refers to the host plant, Alyxia gynopogon , known on Norfolk Island as the Evergreen. The name is treated as a Latinised noun, gender masculine, in genitive case. This name was chosen by receiving multiple nominations during the Norfolk Island Flora and Fauna Society meeting, held on Norfolk Island on the 10 June 2023. Members of the society remarked on the importance of such a species that has managed to “ hairng orn ” (hold its place) on Norfolk Island.

Distribution.

This species is the only Pseudophacopteron present on Norfolk Island, and has been recorded from locations throughout Norfolk Island National Park (Fig. 15 ). The species has also been recorded within Selwyn Reserve, a Norfolk Island Regional Council reserve which adjoins the western border of the National Park (G. Maynard, pers. comm. 2024; Fig. 15 ). The distribution of this species is limited by the distribution of the host plant, which although common within the National Park, is scarce across the rest of the island group. No specimens have been found on the few plants that have been located and inspected outside of the National Park and Selwyn Reserve and it is likely P. aewagriini is confined to the National Park and its immediate surrounds.

Host plant on Norfolk Island.

Alyxia gynopogon Roem. & Schuit. ( Gentianales , Apocynaceae ).

Conservation.

This species is considered endemic to Norfolk Island, as is its host plant, Alyxia gynopogon . The host is not currently regarded as threatened, however, it is almost entirely confined to Norfolk Island National Park, with only scattered specimens known from other areas of the island. Neither species is known from nearby Phillip Island. Despite searching, P. aewagriini is known only from the National Park and the adjoining Selwyn Reserve, meaning the EOO ranges from 1.3–6.8 km 2, based on either confirmed occurrence records, or the entire area of the National Park, Botanic Gardens, and Selwyn Reserve (Fig. 15 ). The corresponding AOO calculated using a 4 km 2 grid overlay, ranges from 16–20 km 2. The range reduction suffered by this species following European colonisation is likely to have ceased in 1984 following the establishment of the National Park. It is likely that A. gynopogon and P. aewagriini increased in range slightly following the cessation of grazing by cattle within the National Park. The species is not known to be undergoing a population or range decline, nor is it known to be facing any ongoing threats. However, Norfolk Island National Park and Selwyn Reserve have been identified as being highly vulnerable to wildfire under optimal fire conditions which could destroy a large proportion of the habitat for P. aewagriini , particularly given Norfolk Island’s ecosystems are not fire-adapted ( Eco Logical Australia 2021). Predicted drying of Norfolk Island’s climate ( Petheram et al. 2020) exacerbates the risk of wildfire, and may also reduce the quality of the rainforest inhabited by this species and its host plant. Invasive Argentine ants ( Linepithema humile ) are established on the island and although they are subject to an extensive control and eradication effort ( NIRC 2021) their spread into the National Park could impact P. aewagriini populations.

We propose that P. aewagriini warrants a threat classification of Vulnerable under criterion D 2 ( IUCN 2012). This species is known from only a single location but is not currently known or suspected to be undergoing continuing decline or extreme fluctuation in its range or population size. However, it has an EOO of 16–20 km 2 and plausible future threats in the form of wildfire which could destroy much of its habitat, ongoing reduction of habitat quality due to predicted climate drying, and Argentine ant invasion. As such, this species could quickly be driven to Critically Endangered under Criteria B if these threats were to materialise ( IUCN 2012). Consideration should be given to establishing populations of A. gynopogon and P. aewagriini in other areas of Norfolk Island, as well as on nearby Phillip Island, to increase the security of both species.

DNA resources.

GenBank COI: MG 988815 , MG 988814 , cytB: MG 989134 , MG 989135 . Also represented in the mitogenome analysis of Percy et al. (2018) as: DP 1. idba. 137, and the annotated mitochondrial genome is in GenBank: MG 989234 ( Percy et al. 2018; see also Fig. 16 ). Additionally, a total of four COI sequences were generated for this study (OR 558312 – OR 558315; Table 1 ).

Systematics.

This species may be related to Pseudophacopteron tuberculatum (Crawford, 1912) which is native to China, southeast Asia, and Papua New Guinea ( PNG) and induces closed galls on the leaves of Alstonia ( Apocynaceae ; Percy et al. 2016; Luo et al. 2018), the same plant family as Alyxia . Although Luo et al. (2018) noted that there are no morphological characters suggesting that all Pseudophacopteron species developing on Apocynaceae constitute a monophyletic group, the molecular data do support P. aewagriini from Norfolk Island and P. tuberculatum (COI GenBank sample MH 769661 ) as likely being in the same clade. Unfortunately, the backbone analysis currently involves inclusion of more short (and non-overlapping) sequences than there are taxa in the original mitogenome data, which makes a rigorous backbone analysis not possible at this time. Morphologically, there are some shared traits with two species described from Brazil, P. aspidospermi Malenovský et al., 2015 and P. longicaudatum Malenovský et al., 2015 , which produce closed leaf galls on Aspidosperma ( Apocynaceae ) ( Malenovský et al. 2015); but overall, more systematic data on this group in the Austro-Pacific region are needed for conclusions to be made.

Remarks.

This species is the first described Pseudophacopteron species known to be associated with Alyxia ( Apocynaceae ). The related Pseudophacopteron tuberculatum is considered a serious pest of plantations of Alstonia scholaris ( Apocynaceae ) in the Philippines ( Braza and Calilung 1981). The host plant of P. aewagriini , Alyxia gynopogon , is a Norfolk Island endemic, evergreen understory shrub, which is relatively common within the National Park. The galling of leaves by P. aewagriini , inducing the characteristic open pit galls on the leaves (Fig. 7 A – C ), does not appear to be overly detrimental to the host. Hollis (2004) and Malenovský (2008) reported the presence of an unnamed species of Pseudophacopteron on Lord Howe Island, where there are three species of Alyxia : the endemic A. lindii and A. squamulosa , and the native A. ruscifolia . A number of Pseudophacopteron species associated with Alyxia , not yet formally described, have been reported from Western Australia (iNaturalist observation 138485676), Queensland ( Malenovský 2008, iNaturalist observation 154392985) and South Australia (G. S. Taylor, pers. comm. 2023). Informal descriptions of two of these species were included in the PhD thesis of Malenovský (2008). These two species are close to Pseudophacopteron aewagriini and all three species belong to the same “ narrow-winged ” clade identified by Malenovský (2008), which also includes a Pseudophacopteron sp. from Papua New Guinea, another species from both Papua New Guinea and Sulawesi, and a third species from Costa Rica ( Malenovský 2008). Malenovský (2008) also noted that the two species from Queensland and Lord Howe Island can be separated from the remaining taxa in the “ narrow-winged ” clade by the presence of a distinct median ridge and anterior bulges or tubercles on the vertex, and these characteristics are shared with P. aewagriini (Fig. 9 D, E, H ). Pseudophacopteron aewagriini can be differentiated from the undescribed taxa occurring in Queensland and Lord Howe Island in the relative length of the paired apical antennal setae, with the two undescribed species showing these setae to be of similar or slightly unequal length, while in P. aewagriini the shorter seta is between 1 / 2–2 / 3 length of the longest seta (Fig. 9 H ). The fore wing of P. aewagriini is distinct in appearing intermediate between the two undescribed species. The overall fore wing structure and shape of P. aewagriini is more similar to the Queensland species but is less narrow as in the Lord Howe Island species. The basal fore wing markings are more similar to that of the Lord Howe Island taxon, without a distinct unpigmented area alongside vein M + Cu, but more similar to the Queensland taxon in the marginal fore wing markings which have larger unpigmented spots in cells cu 1, m 1 and m 2. The extent of marginal pigmentation in cell r 2 is reduced in P. aewagriini compared to either of the undescribed Australian species. Additionally, P. aewagriini shares the seven unsclerotised apical spurs on the metatibia with the Lord Howe Island taxon, versus 11 in the Queensland taxon.

Figures

Figure 7. Psyllids on their host plants A damage caused by the open pit galls of Pseudophacopteron aewagriini Percy & Martoni, sp. nov. on the leaves of Alyxia gynopogon B same, detail of distribution of galls on the upper leaf surface C close up of immatures (orange) seated in the pit galls on the upper leaf surface D lerp of Cardiaspina fiscella on leaves of Eucalyptus sp., the lerp is built by the immatures which live underneath until adulthood E cluster of both immatures and adults of Mesohomotoma hibisci on the new growth of Hibiscus tiliaceus showing production of white waxy filaments F damage caused by Powellia vitreoradiata on Pittosporum bracteolatum, showing the presence of shallow pit galls.

Figure 8. Pseudophacopteron aewagriini Percy & Martoni, sp. nov. A adult lateral habitus of male B same, female C dorsal habitus of male D same, female E fore wing of male F same, female G immature habitus showing type of truncate marginal setae H metatibiotarsus of immature I circumanal ring of immature. Scale bars: 1 mm (A – D); 0.5 mm (E, F); 0.3 mm (G); 0.1 mm (H, I).

Figure 9. Pseudophacopteron aewagriini Percy & Martoni, sp. nov. A fore wing of male B fore wing and hind wing of female C detail of radular spinule cluster positions D head (dorsal view) indicating anterior bulges either side of median ridge E head (anterior view) indicating median ridge and genal tubercles below toruli F head (lateral view) indicating protruding genal tubercles G clypeus and proboscis H head and antennae (with detail inset) indicating median ridge on vertex and position of large rhinaria on segments 4–9, termination of two apical setae is indicated by open arrow heads I male (lateral view) J head and thorax (dorsal view) K thorax from dorsal view L thorax from anterior view indicating medial depression on mesoscutum M hind leg with detail of medial constriction of metafemur (inset) N metatibia apex indicating relatively slender lateral setae O metatarsi showing two metabasitarsus spines.

Figure 10. Pseudophacopteron aewagriini Percy & Martoni, sp. nov. A male terminalia (lateral view) B male terminalia (posterior view) indicating a row of stout setae on dorsal margin C paramere outer surface (left) and inner surface (right), and aedeagus D female terminalia (lateral view) showing irregular profile of anal ring (inset) E ovipositor (lateral view) showing detail of shallow serrations on valvulae dorsalis F female proctiger (dorsal view) with detail of anal ring pores G female subgenital plate (ventral view) indicating truncate and slightly incised apex.

Figure 15. Confirmed occurrence records for Pseudophacopteron aewagriini Percy & Martoni, sp. nov. (triangles) and Acizzia aliceae Percy & Martoni, sp. nov. (circles). The dotted line indicates the boundaries of Norfolk Island National Park and Botanic Gardens. Records shown are derived from both collected material and confirmed records from iNaturalist (https://www.inaturalist.org/) and personal communications. Map constructed in QGIS with satellite imagery sourced from ESRI World Imagery.

Figure 16. Systematic placement of the Norfolk Island psyllid fauna (native taxa in black bold, adventive taxa in red) determined using a maximum likelihood backbone constraint analysis with the mitogenome data from Percy et al. (2018). The two annotated genomes for the endemic species, Acizzia aliceae Percy & Martoni, sp. nov. and Pseudophacopteron aewagriini Percy & Martoni, sp. nov. are illustrated as well as more detailed clade placement for Acizzia spp. (A – Australia, P – Pacific, A-P – Austro-Pacific). Two taxa indicated by [? in grey] are referred to as Glycaspis sp. and Trioza sp. in Maynard et al. (2018) and are considered here to refer to Glycaspis granulata and Powellia vitreoradiata, respectively (see Discussion).