Monograph |
Corresponding author: Diana M. Percy ( diana.percy@ubc.ca ) Academic editor: James Zahniser
© 2018 Diana M. Percy.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Percy DM (2018) Revision of the Hawaiian psyllid genus Swezeyana, with descriptions of seven new species (Hemiptera, Psylloidea, Triozidae). ZooKeys 758: 75-113. https://doi.org/10.3897/zookeys.758.23019
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The endemic Hawaiian genus Swezeyana Caldwell, 1940 is highly distinctive due to the extremely long genal processes. In addition, some of the immatures are ornamented with extraordinary tubercles and tentacles. Two Swezeyana species are redescribed, and seven new species are described, bringing the total number of species in the genus to nine. All species are hosted by a single, endemic host plant, Planchonella sandwicensis (Sapotaceae), which is distributed across all major islands in the archipelago. The majority of Swezeyana species are single island endemics. A sister taxon pair is found sympatrically on the same individual plants on Kauai, and putative sister or at least closely related species are also found sympatrically on Oahu and Hawaii, suggesting these taxa may have diversified in sympatry. However, there is no observed ecological niche partitioning, despite some striking morphological diversity, as all Swezeyana species have free-living immatures that are found on the leaf surface, and therefore no apparent biological shifts are coincident with occupying the same host plant. Two species groups are represented by strikingly different female terminalia structure and endoskeletal development, although ovipositor structure is very similar between the two groups. Mitochondrial DNA barcodes (COI and cytB) are provided for eight of the nine species. A phylogenetic analysis of the mitochondrial barcode regions indicates species relationships within Swezeyana and provides a comparison of genetic divergence with other Hawaiian endemic genera.
jumping plant lice, mitochondrial DNA barcode, Planchonella , Sapotaceae , taxonomy
The Hawaiian Islands are one of the most isolated terrestrial landscapes on earth with high levels of endemism reflecting both limited immigration and in situ diversification (
The Hawaiian psyllid fauna is relatively well known compared to other tropical faunas (
Swezeyana Caldwell, 1940 is an endemic Hawaiian genus with two previously described species, Swezeyana elongagena Caldwell, 1940 and Swezeyana reticulata Caldwell, 1940, which are here redescribed and seven new species are added. All Swezeyana species occur on a single, endemic host plant, Planchonella sandwicensis (Sapotaceae). Planchonella sandwicensis is scattered in abundance, and only occasionally locally common in some areas of the archipelago. However, Swezeyana species are only rarely encountered, and where found, abundances are usually low with only a few individuals collected; although in a short note on Swezeyana,
The adult morphology is most obviously characterized by the extremely long genal processes and some unusual structural features of the fore wing. The fore wing has a more or less extended “pseudopterostigma” which appears as a thickened anterior fore margin extending from a position parallel to the trifurcation of R, M and Cu1 to approximately 1/3 to 1/2 the length of vein Rs. In reference to this feature,
The objective of this study is to detail the diversification and distribution of this unusual and uncommon Hawaiian endemic genus, which provides yet another example of in situ psyllid diversification within the Hawaiian Islands. Understanding parallel processes of potential sympatric diversification in Swezeyana will contribute to our knowledge of speciation processes in Psylloidea more broadly.
Field collections were made in May–July 2002, August 2003, February 2011, May–July 2014. Adults were preserved in 95% ethanol. For morphological examination, ethanol-preserved material was macerated and cleared in 10% potassium hydroxide followed by clove oil, and slide mounted in Canada balsam as described in
Additional taxa sampled for the mitochondrial DNA analysis, with GenBank accession numbers.
Species | Locality | GenBank COI/cytB (publication) |
---|---|---|
Family: Carsidaridae | ||
Mesohomotoma hibisci (Froggatt, 1901) | Society Islands (Moorea) |
KY294174/KY294658 ( |
Society Islands (Raiatea) |
KY294171/KY294655 ( |
|
New Caledonia |
KY294170/KY294654 ( |
|
Singapore |
KY294176/KY294660 ( |
|
Family: Triozidae | ||
Anomocephala unica Tuthill, 1942 | Austral Islands (Rapa) |
KY293698/KY294177 ( |
Bactericera cockerelli (Šulc, 1909) | California |
KY011201/KY011296 ( |
Hemischizocranium aloha (Caldwell, 1940) | Hawaiian Islands (Kauai) | MG988755/MG989062 (this study) |
Hemischizocranium bessi Tuthill, 1956 | Hawaiian Islands (Hawaii) | MG988756/MG989063 (this study) |
Hevaheva maculata Caldwell, 1940 | Hawaiian Islands (Kauai) |
KY293702/KY294181 ( |
Hevaheva minuta Crawford, 1925 | Hawaiian Islands (Kauai) |
KY293703/KY294182 ( |
Hevaheva perkinsi Kirkaldy, 1902 | Hawaiian Islands (Oahu) |
KY293704/KY294183 ( |
Hevaheva silvestris Kirkaldy, 1908 | Hawaiian Islands (Oahu) |
KY293705/KY294184 ( |
Pariaconus iolani (Kirkaldy, 1902) | Hawaiian Islands (Kauai) |
KY293820/KY294297 ( |
Pariaconus proboscideus Percy, 2017 | Hawaiian Islands (Hawaii) |
KY294095/KY294573 ( |
Pariaconus pyramidalis Percy, 2017 | Hawaiian Islands (Hawaii) |
KY294124/KY294607 ( |
Pariaconus mauiensis Percy, 2017 | Hawaiian Islands (Maui) |
KY293841/KY294316 ( |
Stevekenia aiea Percy, 2017 | Hawaiian Islands (Kauai) |
KY971542/KY971544 ( |
Stevekenia nothocestri Percy, 2017 | Hawaiian Islands (Oahu) |
KY971541/KY971543 ( |
Trioza remota Foerster, 1848 | England |
KY294162/KY294646 ( |
Trioza urticae (Linné, 1758) | England |
KY011191/KY011286 ( |
T. urticae | Greece |
KY011122/KY011219 ( |
Norway |
KY011175/KY011270 ( |
|
Poland |
KY011114/KY011212 ( |
Abbreviations used in the descriptions and given in Tables
Group | Species | n | WL | WW | HW | VW | AL | GP | PB | MP | PL | AEL | FP | FSP | RL | EL |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
elongagena | elongagena | 4m 3f | 2.33–2.82 | 0.67–0.80 | 0.55–0.60 | 0.32–0.36 | 0.82–0.97 | 0.41–0.48 | 0.08 | 0.05–0.07 | 0.15–0.17 | 0.10–0.11 | 0.33–0.34 | 0.23–0.26 | 0.17–0.23 | 0.18–0.20 |
atra | 2m 2f | 1.91–2.58 | 0.55–0.71 | 0.50–0.55 | 0.27–0.32 | 0.64–0.65 | 0.32–0.35 | 0.05–0.06 | 0.05–0.06 | 0.09 | 0.08–0.10 | 0.26–0.31 | 0.23–0.24 | 0.13–0.15 | – | |
hawaiiensis | 0m 2f | 2.33–2.38 | 0.73–0.76 | 0.55–0.58 | 0.30–0.35 | 0.55 | 0.31–0.33 | 0.06 | – | – | – | 0.32 | 0.30 | 0.18 | – | |
magna | 1m 0f | 3.38 | 0.92 | 0.70 | 0.39 | 1.12 | 0.52 | 0.08 | 0.13 | 0.17 | 0.15 | – | – | – | – | |
oahuensis | 4m 3f | 2.09–2.88 | 0.61–0.85 | 0.49–0.58 | 0.28–0.33 | 0.68–0.88 | 0.35–0.36 | 0.06–0.07 | 0.05 | 0.12–0.13 | 0.08–0.10 | 0.27–0.30 | 0.20–0.24 | 0.14–0.16 | – | |
rubra | 2m 7f | 1.79–2.30 | 0.61–0.79 | 0.50–0.57 | 0.29–0.33 | 0.52–0.56 | 0.27–0.33 | 0.05–0.07 | 0.10–0.11 | 0.11 | 0.10–0.11 | 0.33–0.39 | 0.23–0.28 | 0.17–0.21 | 0.16–0.21 | |
reticulata | reticulata | 5m 5f | 1.91–2.58 | 0.55–0.79 | 0.45–0.53 | 0.26–0.30 | 0.61–0.71 | 0.30–0.38 | 0.06 | 0.09–0.10 | 0.09–0.10 | 0.11–0.14 | 0.34–0.43 | 0.22–0.30 | 0.14–0.19 | 0.12–0.21 |
tentaculata | 4m 4f | 1.94–2.53 | 0.58–0.77 | 0.47–0.55 | 0.27–0.32 | 0.76–0.77 | 0.35–0.44 | 0.07–0.08 | 0.10–0.12 | 0.11–0.12 | 0.13–0.14 | 0.46–0.52 | 0.36–0.38 | 0.18–0.23 | 0.20 | |
unplaced | magnaccai | 4m 0f | 1.55–1.76 | 0.45–0.52 | 0.41–0.42 | 0.24 | 0.58 | 0.26–0.32 | 0.05–0.06 | 0.08–0.10 | 0.10 | 0.10–0.13 | – | – | – | – |
Group | Species | WL:WW | CUR | MR | HW:VW | HW:GP | VL:GP | VL:VW | AL:HW | HW:HT | HT:HF |
---|---|---|---|---|---|---|---|---|---|---|---|
elongagena | elongagena | 3.42–3.66 | 1.71–2.06 | 0.75–0.90 | 1.64–1.71 | 1.20–1.32 | 0.54–0.63 | 0.74–0.82 | 1.54–1.78 | 1.63–1.65 | 0.79–0.92 |
atra | 3.40–3.68 | 1.59–1.82 | 0.78–0.86 | 1.70–1.83 | 1.43–1.64 | 0.57–0.73 | 0.72–0.76 | 1.30 | 1.79–1.94 | 0.77–0.83 | |
hawaiiensis | 3.14–3.21 | 1.35–1.61 | 0.75–0.83 | 1.65–1.80 | 1.73–1.76 | 0.78–0.82 | 0.78–0.80 | 0.95–1.00 | 2.00–2.11 | 0.75–0.82 | |
magna | 3.66 | 2.18 | 0.85 | 1.77 | 1.35 | 0.59 | 0.77 | 1.61 | 1.64 | 0.85 | |
oahuensis | 3.36–3.57 | 1.63–2.08 | 0.78–0.93 | 1.68–1.79 | 1.40–1.58 | 0.64–0.75 | 0.77–0.84 | 1.39–1.53 | 1.74–1.90 | 0.72–0.86 | |
rubra | 2.88–3.06 | 1.15–1.32 | 0.77–0.92 | 1.65–1.76 | 1.69–1.89 | 0.69–0.87 | 0.68–0.75 | 0.93–1.03 | 1.82–2.09 | 0.75–0.87 | |
reticulata | reticulata | 3.27–3.55 | 1.50–1.71 | 0.58–0.93 | 1.65–1.78 | 1.39–1.60 | 0.60–0.76 | 0.75–0.82 | 1.25–1.40 | 1.53–1.88 | 0.74–0.83 |
tentaculata | 3.16–3.39 | 1.33–1.64 | 0.83–1.00 | 1.67–1.72 | 1.15–1.35 | 0.56–0.63 | 0.76–0.83 | 1.40–1.61 | 1.41–1.80 | 0.71–0.86 | |
unplaced | magnaccai | 3.29–3.50 | 1.58–1.73 | 0.80–0.90 | 1.69–1.73 | 1.31–1.59 | 0.62–0.76 | 0.81 | 1.41 | 1.73–2.25 | 0.63–0.76 |
Group | Species | PL:HW | MP:PL | PL:AEL | AEL:AELH | PL:SH | FP:HW | FP:RL | FP:SP |
---|---|---|---|---|---|---|---|---|---|
elongagena | elongagena | 0.29–0.31 | 0.31–0.43 | 1.46–1.56 | 2.00–2.33 | 0.95–1.05 | 0.55–0.56 | 1.41–1.95 | 1.24–1.45 |
atra | 0.18 | 0.59–0.73 | 0.92–1.10 | 2.00–2.18 | 0.67–0.85 | 0.51–0.57 | 2.05–2.06 | 1.10–1.34 | |
hawaiiensis | – | – | – | – | – | 0.59 | 1.82 | 1.05 | |
magna | 0.24 | 0.76 | 1.14 | 2.64 | 1.05 | – | – | – | |
oahuensis | 0.25–0.26 | 0.38 | 1.19–1.60 | 2.00–2.17 | 0.94–1.00 | 0.53 | 1.90–2.05 | 1.27–1.36 | |
rubra | 0.22 | 0.96–1.00 | 1.04–1.08 | 2.25–2.27 | 0.80 | 0.61–0.69 | 1.71–2.19 | 1.20–1.41 | |
reticulata | reticulata | 0.19 | 1.00–1.18 | 0.65–0.79 | 2.27–2.80 | 0.79–0.92 | 0.69–0.78 | 2.17–2.45 | 1.34–1.56 |
tentaculata | 0.25–0.26 | 0.93–1.03 | 0.81–0.88 | 2.25–2.57 | 0.78–0.93 | 0.86–0.95 | 2.24–2.59 | 1.27–1.42 | |
unplaced | magnaccai | 0.24–0.25 | 0.76–0.92 | 0.78–1.08 | 2.18–2.67 | 0.83–1.00 | – | – | – |
Swezeyana Caldwell, 1940: 389. Type species: Swezeyana elongagena Caldwell, 1940, by original designation.
Adult. General colour variable ranging from pale yellow-brown, to green or yellow-green, to almost black; often with pink or reddish highlights on the fore wing as well as on the body, especially genal processes, legs, and abdomen. Fore wing membrane either with distinct darker patches or clouds of pigmentation, these range from dark brown to red, and in some cases are limited to termination of veins at wing margins and around cross veins between Rs and wing margin, if without distinct patterns of pigmentation, appearing uniformly clear, opaque yellow or fuscous; wing veins pale to red or dark brown, cross veins between Rs and ventral wing margin with or without pigmentation. Adult length including fore wing from 2–5 mm. Fore wing elongate and usually narrow (ratio WL:WW > 2.80, often > 3), acute to bluntly acute apically, either with trifurcation of veins R, M and Cu1, or with vein R branching anterior of bifurcation of M and Cu1; vein Rs long, reaching wing margin distad of M fork, but either with or without complete extension of Rs to wing margin, incomplete termination of Rs usually marked by pigmentation; vein R shorter than Cu1 and terminating at base of Rs, a pseudopterostigma is present between base of Rs and wing margin, and a more or less thickened wing margin (C+Sc) is present from the wing base to the pseudopterostigma, in some cases occupying part or entire area of cell c+sc; with or without one or more partial or complete cross veins traversing cell r1 between vein Rs and ventral wing margin; a single, broadly shaped marginal cluster of radular spines (Figs
Egg. Known for four species. Pale or light brown, oblong-ovoid with a short, laterally positioned pedicel sub-basally on underside; distinctly hexagonal, honeycomb-like, sculpturing, to semi-hexagonal or rounded indentations dorsally; underside unsculptured, tail apparently lacking.
Immature. Known for four species. 5th instar oblong-ovoid, ventro-dorsally flattened with slightly protruding wing buds and distinct humeral lobes; antennae with 3(-4) segments bearing 3(-4) rhinaria (1 on segments 2-3, and 2 on apical segment) and two long, terminal, simple setae of unequal length; tarsi with broad crescent arolia and extremely small, reduced claws; each terminal tarsus bearing a long capitate seta; anus situated ventrally, circumanal ring broad and composed of a single row of elongate cells; dorsum either with wax producing pores (see
All species for which the biology is known have free-living immatures on the surface of leaves (either lower, or both upper and lower surfaces). Those species with immatures described here with protruding tubercles and tentacles were mostly found on the lower leaf surface among dense indumentum and often close to the mid-rib (Fig.
All Swezeyana are host specific on a single Hawaiian endemic host plant species, Planchonella sandwicensis (Sapotaceae).
Two species groups are recognized, elongagena group and reticulata group, based primarily on the strikingly different forms of female terminalia. The elongagena group has broad, truncate female terminalia with a strongly convex proctiger apex; the proctiger and subgenital plate bear a small to pronounced medial cleft at the apex. In contrast, the reticulata group has tapering terminalia without a medial cleft in the proctiger apex. In both species groups the subgenital plate terminates in a more or less well developed beak with small to pronounced cleft spanned by a membrane. The underlying endoskeleton of the two different forms of female terminalia indicate distinctly different development of the apodemes in the two species groups: broad and short in elongagena group (Fig.
The two species groups (elongagena group and reticulata group) are most easily recognized by the shape of the female terminalia, e.g., extremely convex apex of female proctiger in the elongagena group, versus more or less dorsally straight and tapering in the reticulata group. The elongagena group females have a FP:HW ratio typically < 0.70 (range 0.51–0.69), and FP:RL ratio typically < 2.18 (range 1.41–2.19); whereas in the reticulata group FP:HW ratio is typically > 0.70 (range 0.69–0.95), and FP:RL ratio is typically > 2.18 (range 2.17–2.59). Swezeyana males are less easily assigned to a species group, but elongagena group males have a distal aedeagus segment that is typically shorter than the paramere (PL:AEL ratio range 0.92–1.60), whereas reticulata group males have a distal aedeagus segment that is longer than the paramere (PL:AEL ratio range 0.65–0.88). Notably, the fore wing characters used by
The neighbour-joining analysis of two mitochondrial DNA regions is presented in Fig.
1 | Fore wings with distinct darker patches or clouds of pigmentation, in some cases only around termination of veins at wing margins and around cross veins between Rs and wing margin in cell r1 (Fig. |
2 |
– | Fore wings without distinct darker patches or clouds of pigmentation, appearing uniformly clear or opaque, cross veins between Rs and wing margin in cell r1, if present, unpigmented (Fig. |
6 |
2 | Antennae short, subequal to head width (ratio AL:HW < 1.1), ratio HW:GP > 1.65, female proctiger strongly convex apically with apex extremely broad and blunt, ratio FP:HW < 0.70, on Hawaii | 3 |
– | Antennae longer (AL:HW > 1.1), ratio HW:GP < 1.65, female proctiger more or less straight dorsally with apex bluntly acute, on other islands | 4 |
3 | Fore wings with extensive patches and clouds of red-brown pigmentation, particularly across the central area of wing, and numerous cross veins (typically more than 5) between Rs and wing margin in cell r1, smaller species with broader wings (ratio WL:WW < 3.1) and wing cell cu1 relatively narrow and high (ratio CUR < 1.33) (Figs |
S. rubra sp. n. |
– | Fore wings with only indistinct fuscous brown on membrane and distinct small darker brown patches around termination of veins at wing margins and around cross veins between Rs and wing margin in cell r1, cross veins fewer (typically less than 5), larger species with narrower wings (ratio WL:WW > 3.1) and wing cell cu1 relatively wide and low (ratio CUR > 1.33) (Figs |
S. hawaiiensis sp. n. |
4 | Larger species (WL > 1.9 mm), paramere shape more triangular with a broader base, on Kauai (possibly other islands for S. reticulata) | 5 |
– | Smaller species (WL < 1.9 mm), paramere shape more slender with a narrower base, on Oahu (Figs |
S. magnaccai sp. n. |
5 | Fore wing with fewer cross veins (typically less than 6) between Rs and wing margin, head with shorter genal processes (ratio HW:GP > 1.36) and shorter antennae (AL < 0.75 mm, ratio AL:HW ≤ 1.40), paramere shorter and broader (ratio PL:HW < 0.20, ratio PL:AEL < 0.80), female terminalia shorter (ratio FP:HW < 0.80) with posterior margin of anal ring less convoluted and incised (Figs |
S. reticulata Caldwell, 1940 |
– | Fore wing with more cross veins (typically more than 6) between Rs and wing margin, head with longer genal processes (ratio HW:GP < 1.36) and longer antennae (AL > 0.75 mm, ratio AL:HW ≥ 1.40), paramere longer and narrower (ratio PL:HW > 0.20, ratio PL:AEL > 0.80), female terminalia longer (ratio FP:HW > 0.80) with posterior margin of anal ring more convoluted and incised (Figs |
S. tentaculata sp. n. |
6 | Smaller species (WL < 3 mm, AL < 1 mm), wing cell cu1 relatively narrow and high (ratio CUR < 2.1), on Oahu, Molokai, Maui | 7 |
– | Larger species (WL > 3 mm, AL > 1 mm), wing cell cu1 relatively wide and low (ratio CUR > 2.1), on Kauai (Figs |
S. magna sp. n. |
7 | Genal processes shorter (GP < 0.40 mm, ratio HW:GP > 1.35), paramere shorter (ratio PL:HW < 0.27) and with less extended anteriorly directed apex, on Oahu | 8 |
– | Genal processes longer (GP > 0.40 mm, ratio HW:GP < 1.35), paramere longer (ratio PL:HW > 0.27) and with more extended anteriorly directed apex, on Molokai and Maui (Figs |
S. elongagena Caldwell, 1940 |
8 | Paler species (generally yellow-brown to green), fore wing vein Rs typically longer relative to wing length (ratio WL:Rs 1.57–1.82) resulting in shorter distance between terminations of Rs and M1+2, antennae longer (AL > 0.65 mm), paramere longer (ratios PL:HW > 0.20, PL:AEL > 1.15, PL:SH > 0.90) (Figs |
S. oahuensis sp. n. |
– | Darker species (generally dark brown to black), fore wing vein Rs typically shorter relative to wing length (ratio WL:Rs 1.76–2.03) resulting in longer distance between terminations of Rs and M1+2, antennae shorter (AL ≤ 0.65 mm), paramere shorter (ratios PL:HW < 0.20, PL:AEL < 1.15, PL:SH < 0.90) (Figs |
S. atra sp. n. |
Swezeyana is a small genus with, in general, considerable morphological homogeneity. The species descriptions below provide details of species specific characteristics not supplied in the generic description above.
Swezeyana elongagena Caldwell, 1940: 390.
Adult. General body colour green to yellow-green or yellow-brown, last 3-5 antennal segments darker brown to black, apices of genae sometimes pinkish-red. Fore wing membrane uniformly pale fuscous (Fig.
Fore wings of nine Swezeyana species: A S. elongagena (male) B S. oahuensis (male) C S. atra (male) D S. magna (male) E S. hawaiiensis (female) F S. magnaccai (male) G S. reticulata (male above, female below) H S. tentaculata (male above, female below) I S. rubra (male above, female below). Scale bars: 1 mm.
Egg. Pale with well-defined hexagonal (honeycomb-like) sculpturing dorsally (Fig.
Immature. Described and illustrated by
Planchonella sandwicensis.
Maui, Molokai (a single female specimen recorded from Kauai, and apparently now missing, is queried in
Although
Holotype female (slide mounted), Haelaau, Maui, USA, ex Planchonella sp., 19 December 1928 (BPBM). Paratypes: 10m 5f, same data as holotype (not located). Other material: 5m 4f, Kamakou Preserve, Molokai, USA, N21.1236, W-156.9108, ex Planchonella sandwicensis, 17 August 2003, “Hi20-03” D. Percy leg. (BMNH).
Medium sized, dark coloured species, with fore wing membrane unpatterned, antennae medium short, genal processes long, paramere short, and female proctiger strongly convex apically.
Adult. General body colour brown to black, particularly dark on the dorsum of head and thorax. Fore wing membrane generally uniformly clear or slightly fuscous, with fuscous-brown cloud usually present around vein R and basal dorsal claval margin (Fig.
Egg. Unknown.
Immature. Unknown.
Planchonella sandwicensis.
Oahu. Only known from the Waianae Mountains.
Named for the dark body colouration, especially the head and thorax (adjective in the nominative singular).
This is the darkest of the Swezeyana species. It has the shortest paramere in the elongagena group, with the shape more similar to those in the reticulata group. The distribution in the Waianae Mountains is shared with S. oahuensis, and the molecular topology places these two species as sister taxa but with weak bootstrap support (Fig.
Neighbour-joining (NJ) analysis (combined COI and cytB data) with 1000 bootstrap replicates in PAUP*. Eight of the nine Swezeyana species are included and 16 other taxa from Triozidae, mostly representing other Hawaiian genera for comparison of divergence; and one species from Carsidaridae as an outgroup (Mesohomotoma hibisci) (Table
Swezeyana elongagena. A head B head (lateral view) C male D head and antenna, inset detail of terminal antennal segments (terminal setae outlined) E female terminalia F detail of apex of female terminalia indicating beak and position of medial clefts in proctiger and subgenital plate (outlined) G male terminalia H paramere and distal aedeagus segment I paramere, inset detail of apex J eggs (distinctly hexagonal sculpturing and pedicel outlined and indicated) K hind leg L base of hind tibia with reduced genual spine indicated M mesotarsi and metatarsi (outlined), concave and ridged underside of basal metatarsus (outlined) N small but distinct meracanthus (indicated) O fore wing with interior edge of ventral margin outlined, inset illustrating broad shape of marginal radular spine cluster P extent of fore wing pseudopterostigma (shaded).
Swezeyana atra sp. n. A head B head and antenna (lateral view) C antenna D proboscis E dorsum of thorax F male terminalia, inset distal aedeagus segment G paramere and distal aedeagus segment H parameres (dorsal view), inset illustrating paramere apex I paramere (posterior view) J female abdomen K female terminalia L female proctiger (dorsal view) M detail of anal ring N female subgenital plate (ventral view) O detail of posterior apex of female subgenital plate with membrane (outlined) P female terminalia endoskeleton (dorsal view, outlined) Q hind leg, inset reduced meracanthus (indicated) and metatarsi (outlined) R base of hind tibia with highly reduced genual spine (indicated) S extent of fore wing pseudopterostigma (shaded) T fore wing (above) with interior edge of ventral margin outlined, hind wing (below).
Holotype male (slide mounted), Waianae Mnts, Oahu, USA, N21.4585, W-158.0973, ex Planchonella sandwicensis, 5 July 2014, “Hi65-14” D. Percy leg. (BMNH). Paratype (slide mounted) 1f, as for holotype (BMNH). Other material: 1m 1f, Puu Hapapa, Central Waianae Mnts, Oahu, USA, N21.4666, W-158.1029, ex Planchonella sandwicensis, 17 May 2014, “KM14-14” K. Magnacca leg. (BMNH).
Medium sized, light coloured species, with fore wing membrane unpatterned, antennae and genal processes relatively short, and female proctiger strongly convex apically.
Adult. General body colour green to yellow-green. Fore wing membrane generally slightly fuscous, darker fuscous clouds around cross pseudoveins towards apex of cell r1, and distinct brown patches at termination of veins Cu1a, Cu1b, and M3+4 (Figs
Swezeyana hawaiiensis sp. n. (female). A head and antenna B antenna C proboscis D proctiger, dorso-lateral view showing anal ring (outlined) E detail of apex of proctiger showing medial cleft and fringe of apical setae (indicated) F female subgenital plate (ventral view) with apical beak and membrane outlined G hind leg H small but distinct meracanthus (indicated) I base of hind tibia (highly reduced genual spine indicated) J detail of atypical 1+3 (indicated) arrangement of sclerotized apical metatibia spurs K fore wing, with interior edge of ventral margin outlined.
Egg. Unknown.
Immature. Free-living immatures were observed mostly on the upper, but also on the lower, leaf surfaces. Specimens collected were unfortunately lost during specimen shipping.
Planchonella sandwicensis.
Hawaii. Only known from PuuWaaWaa area.
Named for its distribution on the island of Hawaii (adjective in the nominative singular).
This species was collected from the same individual host tree as S. rubra; both species are in the elongagena group but are easily separated in the field due to general body colour and a distinctly patterned fore wing in S. rubra; both species have comparatively short genal processes as well as the shortest antennae in the genus (subequal to head width). The molecular topology places these as sister taxa, but without bootstrap support. Males with the same collection data as females were unfortunately lost during specimen shipping.
Holotype female (slide mounted), PuuWaaWaa, Hawaii, USA, N19.784, W-155.833, 820m, ex Planchonella sandwicensis, 29 July 2002, “440A-02” D. Percy leg. (BMNH). Paratype (slide mounted) 1f, as for holotype (BMNH).
Large, light coloured species, with fore wing membrane unpatterned, antennae and genal processes long, and paramere short.
Adult. General body colour yellow-green to yellow-brown, last 7-8 antennal segments darker brown. Fore wing membrane uniformly pale fuscous (Fig.
Swezeyana magna sp. n. A head and antenna, inset antenna detail B hind leg C base of hind tibia (reduced genual spine indicated) D small but distinct meracanthus (indicated) E metatarsi, inset comparative size of mesotarsi F dorsum of thorax G proboscis H aedeagus and paramere I extent of pseudopterostigma (shaded) J broad shape of marginal radular spine cluster (outlined) K fore wing, with interior edge of ventral margin outlined.
Egg. Unknown.
Immature. Unknown.
Planchonella sandwicensis.
Kauai. Only known from one location in Kokee State Park.
Named for the large body size (adjective in the nominative singular).
This is the largest Swezeyana species and is only known from a single male; fore wing type suggests it is part of the elongagena species group, but the paramere shape is somewhat similar to other reticulata group species on Kauai. As no molecular sequences are available for this species, the group affiliation remains uncertain, but this species and the other Kauai species may represent early divergence of the elongagena and reticulata species groups.
Holotype male (slide mounted), Kokee State Park, Kauai, USA, N22.1444, W-159.6477, ex Planchonella sandwicensis, 29 October 2005, “Hi01-05” D. Percy leg. (BMNH).
Medium sized, light coloured species, with fore wing membrane unpatterned, antennae medium long, genal processes long, paramere medium long, and female proctiger strongly convex apically.
Adult. General body colour green to yellow-green or yellow-brown, last 5-7 antennal segments darker brown, apices of genae sometimes pinkish-red. Fore wing membrane uniformly pale fuscous (Fig.
Swezeyana oahuensis sp. n. A head B head and antenna (lateral view) C proboscis D antenna E hind leg, inset detail of reduced meracanthus (indicated) and genual spine F dorsum of thorax G female H female terminalia (truncate subgenital plate indicated, apex outlined) I female terminalia (dorsal view) J detail of anal ring (outlined) K female subgenital plate (ventral view) L detail of posterior apex of female subgenital plate with beak and membrane (outlined) M male terminalia (dorsal view) N paramere apex (dorsal view above and outlined, lateral view below) O male terminalia P paramere (posterior view) Q aedeagus and paramere R fore wing, with interior edge of ventral margin outlined.
Egg. Unknown.
Immature. Unknown.
Planchonella sandwicensis.
Oahu. Only known from the Waianae Mountains.
Named for its distribution on the island of Oahu (adjective in the nominative singular).
This species and S. atra may represent insular diversification on Oahu (see comments for S. atra).
Holotype male (slide mounted), Mnt Kaala road (culvert 32), Waianae Mnts, Oahu, USA, ex Planchonella sandwicensis, 26 August 2003, “Hi57-03” D. Percy leg. (BMNH). Paratypes (slide mounted) 2f, as for holotype (BMNH). Paratypes (slide mounted) 2m, Pahole NAR, Waianaea Mnts, Oahu, USA, N21.5364, W-158.1919, ex Planchonella sandwicensis, 14 August 2003, “Hi06-03” D. Percy leg. (BMNH). Other material: 1m 2f, South Mohiakea, Central Waianae Mnts, Oahu, USA, N21.4821, W-158.1247, ex Planchonella sandwicensis, 29 January 2014, “KM16-14” K. Magnacca leg. (BMNH).
Gene sequences.KY294142 (COI) KY294626 (cytB) (KM16-14) [previously submitted to GenBank as Swezeyana elongagena Caldwell, 1940 (in
Medium small, red-brown species, with fore wing membrane distinctly patterned, antennae and genal processes relatively short, paramere short, and female proctiger strongly convex apically.
Adult. General body colour red or red-brown, last 2-3 antennal segments darker brown. Fore wing distinctly patterned with irregular clouds of red pigmentation, mottled red-brown pattern in apical 2/3 of fore wing, with basal portion either clear (males) or slightly mottled (females), males have a darker almost solid red-brown area of pigmentation across middle of wing membrane, wing veins variably brown to speckled brown with darker brown patches indicating position of cross pseudoveins, intersections of veins and wing margin, as well as two brown patches on the dorsal claval wing margin, and on vein R+M+Cu1 just basal to vein trifurcation, there are distinctly unpigmented areas surrounding marginal clusters of radular spines (Fig.
Swezeyana rubra sp. n. A head B head (lateral view) C female D head and antenna E antenna F proboscis G reduced meracanthus (indicated) H hind leg I metatarsi (outlined), inset comparative size of mesotarsi (outlined) J base of hind tibia K dorsum of thorax L female terminalia (subgenital beak indicated, apex outlined) M female proctiger (dorsal view) N female terminalia (dorsal view), inset apex of proctiger (ventral view, cleft indicated) O detail of anal ring (outlined) P female subgenital plate (ventral view) Q detail of posterior apex of female subgenital plate with beak and membrane (outlined) R aedeagus and paramere S male terminalia, inset aedeagus T paramere (posterior view) U eggs (semi-hexagonal sculpturing, pedicel and unsculptured underside outlined and indicated) V fore wing, with interior edge of ventral margin outlined W fore wing detail of pigmented cross veins.
Egg. Pale with loosely structured hexagonal sculpturing dorsally (Fig.
Immature. Unknown.
Planchonella sandwicensis.
Hawaii. Only known from PuuWaaWaa area.
Named for the generally red body colouration (adjective in the nominative singular).
This species was collected from the same individual host tree as S. hawaiiensis (see comments for S. hawaiiensis).
Holotype male (slide mounted), PuuWaaWaa, Hawaii, USA, N19.784, W-155.833, 820m, ex Planchonella sandwicensis, 29 July 2002, “440B-02” D. Percy leg. (BMNH). Paratypes (slide mounted) 2f, as for holotype (BMNH). Other material: 2m 8f, PuuWaaWaa Forest Reserve, Hawaii, USA, 2600 ft, ex Planchonella sandwicensis, 23 February 2011, “JG5B” J. Giffin leg. (BMNH).
Swezeyana reticulata Caldwell, 1940: 390.
Adult. General body colour yellow-brown to darker brown, last 2-3 antennal segments darker brown. Fore wing patterned with irregular clouds of brown pigmentation (although less distinctly than in S. rubra and S. tentaculata), darker brown patches indicate position of cross pseudoveins, intersections of veins and wing margin, as well as 1-2 brown patches on the dorsal claval wing margin, and a more or less distinct patch on vein R+M+Cu1 just basal to vein trifurcation, unpigmented areas surround the marginal clusters of radular spines (Fig.
Swezeyana reticulata. A head B head and antenna (lateral view) C detail of antenna D hind leg, inset highly reduced meracanthus (indicated) and base of hind tibia with genual spine (indicated) E male F female G dorsum of thorax H head and antenna I metatarsi (outlined) J female proctiger (dorsal view) K detail of anal ring (outlined), illustrating circumanal ring pores L female terminalia (subgenital beak indicated, apex outlined) M female subgenital plate (ventral view, apex outlined) N detail of posterior apex of female subgenital plate with beak and membrane (outlined) O ovipositor P female terminalia (dorsal view), lateral valves extending beyond proctiger Q male terminalia R aedeagus and paramere, with details of paramere apex (above interior view, below dorsal view) S fore wing, with interior edge of ventral margin outlined T fore wing detail of pigmented cross veins.
Egg. Pale with shallow hexagonal indentations dorsally.
Immature. Colour: Mottled, cream and red-brown. Structure: 5th instar with circumanal ring wide, and more or less straight, with a single row of uninterrupted elongate cells (Fig.
Immature measurements (mm) and ratios: 5th instar (n = 4): BL 1.67–1.71; BW 1.06–1.15; WPL 0.85–0.88; CPL 0.73–0.79; CPW 0.62–0.97; RW 0.17–0.18; HW 0.52–0.57; AL 0.19–0.20; BL:BW 1.49–1.57; HW:AL 2.60–2.96; CPW:RW 3.70–5.77.
Planchonella sandwicensis.
Kauai (possibly also on Maui, see comments). Appears to be the most common of the three Swezeyana species found on Kauai.
Holotype female (BPBM, not located). Other material: 1f, Nualolo Trail, Kokee State Park, Kauai, USA, on Polyscias waimeae, 25 May 2002, “370-02” D. Percy leg. (BMNH). 10m 4f 7i, Kokee State Park, Kauai, USA, N22.1444, W-159.6477, ex Planchonella sandwicensis, 29 October 2005, “Hi01-05” D. Percy leg. (BMNH). 5m 1f, Kokee State Park, Kauai, USA, N22.1503, W-159.6453, ex Planchonella sandwicensis, 29 October 2005, “Hi02-05” D. Percy leg. (BMNH). 12m 7f, Kokee State Park, Kauai, USA, N22.1309, W-159.6388, ex Planchonella sandwicensis, 30 October 2005, “Hi05-05” D. Percy leg. (BMNH). 1m 10f, Kokee State Park, Kauai, USA, N22.0948, W-159.6953, ex Planchonella sandwicensis, 30 October 2005, “Hi11-05” D. Percy leg. (BMNH).
Medium sized, red-brown species, with fore wing membrane patterned, antennae medium long, genal processes long, paramere short, and female proctiger more or less straight dorsally.
Adult. General body colour red to red-brown, last 2-3 antennal segments darker brown. Fore wing distinctly patterned with irregular clouds of red-brown pigmentation, darker brown patches indicate position of cross pseudoveins, intersections of veins and wing margin, as well as two brown patches on the dorsal claval wing margin, and on vein R+M+Cu1 just basal to vein trifurcation, there are distinctly unpigmented areas surrounding marginal clusters of radular spines (Figs
Swezeyana tentaculata sp. n. A head B head (lateral view) C head and antenna (lateral view) D dorsum of thorax E antenna F head and antenna G proboscis H hind leg, inset highly reduced meracanthus (indicated) and base of hind tibia with genual spine (indicated) I female terminalia endoskeleton (dorsal view) J female terminalia (subgenital beak indicated, apex outlined) K female proctiger (dorsal view) L female subgenital plate (ventral view, apex outlined) M detail of posterior apex of female subgenital plate with beak and membrane (outlined) N detail of anal ring (dorsal view, outlined) O egg (outlined), inset detail of sculpturing on dorsal service P aedeagus and paramere Q male terminalia R fore wing (above), with interior edge of ventral margin outlined, hind wing (below) S fore wing detail of pigmented cross veins and unpigmented membrane surrounding marginal radular spine clusters.
Egg. Pale, sculpturing consisting of rounded indentations dorsally (Fig.
Immature. Colour: Mostly red-brown, some cream mottling. Structure: 5th instar with circumanal ring wide, slightly constricted medially and lateral apices upturned, with a single row of uninterrupted elongate cells (Fig.
Immature measurements (mm) and ratios: 5th instar (n = 3): BL 1.48–1.52; BW 0.91–0.97; WPL 0.73–0.76; CPL 0.64; CPW 0.76; RW 0.16–0.17; HW 0.48–0.52; AL 0.18; BL:BW 1.56–1.63; HW:AL 2.61–2.95; CPW:RW 4.51–4.92.
Planchonella sandwicensis.
Kauai. Only known from Kokee State Park.
Named for the distinctly long tentacles on the dorsum of immatures (adjective in the nominative singular).
Found sympatrically with S. reticulata and S. elongagena on the same individual plants. Immatures were observed among the ferugineous trichomes on the undersides of leaves, often along the leaf mid-rib (Fig.
Holotype male (slide mounted), Kokee State Park, Kauai, USA, N22.1444, W-159.6477, ex Planchonella sandwicensis, 29 October 2005, “Hi01-05” D. Percy leg. (BMNH). Paratypes (slide mounted) 3f 7i, as for holotype (BMNH). Other material: 2m 2f, Kokee State Park, Kauai, USA, N22.1309, W-159.6388, ex Planchonella sandwicensis, 30 October 2005, “Hi05-05” D. Percy leg. (BMNH).
MG989157 (cytB) (Hi01-05).
Small, red- to yellow-brown species, with fore wing membrane patterned, antennae and genal processes medium long, and paramere short.
Adult. General body colour orange-red to yellow-brown, last 2-3 antennal segments darker brown. Fore wing patterned with irregular clouds of orange-brown pigmentation, darker patches indicate position of cross pseudoveins, intersections of veins and wing margin, as well as 1-2 darker patches on the dorsal claval wing margin, and a more or less distinct patch on vein R+M+Cu1 just basal to vein trifurcation, unpigmented areas surround the marginal clusters of radular spines (Figs
Swezeyana magnaccai sp. n. A head B head and antenna (lateral view) C proboscis D dorsum of thorax E hind leg F base of hind tibia G male terminalia H aedeagus and paramere I male terminalia (dorsal view), inset details of paramere apices J fore wing detail of termination of vein R at base of pseudopterostigma K fore wing detail of incomplete termination of vein Rs at wing margin (inset incomplete veins indicated) L fore wing, with interior edge of ventral margin outlined M fore wing detail of unpigmented membrane surrounding marginal radular spine clusters.
Swezeyana reticulata and Swezeyana tentaculata 5th instar immatures. A–G, M S. reticulata: A detail of dorsal lanceolate setae with inflated and ridged bases anterior of eye B detail of dorsal sub-marginal lanceolate setae with inflated and ridged bases on margin of wing pads C detail of tubercles on margin of abdomen, and marginal narrow, blunt sectasetae D detail of dorsal tubercle bearing small simple setae, and small lanceolate setae with greatly inflated and ridged bases on surrounding surface E lateral view showing arrangement of dorsal tubercles, open arrows indicate position of thoracic and abdominal tubercles typically more darkly pigmented F dorsal view, open arrows indicate position of thoracic and abdominal tubercles typically more darkly pigmented G anal ring H–L, N S. tentaculata: H dorsal view, open arrows indicate position of thoracic and abdominal tentacles typically more darkly pigmented, inset detail of marginal pointed sectasetae I anal ring J, K detail of dorsal sub-marginal long, simple setae with narrowly inflated and ridged bases, K also shows different pigmentation for 1st and 2nd tentacle on abdomen margin L detail of long tentacle with simple setae towards the apex and a pair of small simple setae apically, and longer slightly capitate rod setae towards the base and on surrounding surface M tarsus and antenna (similar for both species) N red-brown S. tentaculata immatures found along the midribs on undersides of leaves among the red-brown leaf trichomes.
Swezeyana reticulata and Swezeyana tentaculata 1st-4th instar immatures. A–F S. reticulata: A 1st instar, inset detail of marginal narrow, blunt sectasetae B 2nd instar with appearance of tubercles C detail of 2nd instar anterior marginal and sub-marginal head setae D detail of 2nd instar marginal tubercles on the thorax bearing simple setae towards apices E 3rd instar, inset detail of marginal narrow, blunt sectasetae F 4th instar, inset detail of dorsal and sub-marginal lanceolate setae with inflated and ridged bases G–J S. tentaculata: G 4th instar, with details of marginal pointed sectasetae, and dorsal and sub-marginal simple setae with narrowly inflated and ridged bases H 3rd instar, with detail of larger dorso-medial tubercles bearing spiral of slightly capitate rod setae; marginal pointed sectasetae, and dorsal and sub-marginal simple setae with narrowly inflated and ridged bases as for 4th instar I detail of 3rd instar pairs of slightly capitate rod setae near the apices of marginal tubercles on the abdomen J detail of 3rd instar marginal pointed sectasetae, and dorsal sub-marginal simple setae.
Egg. Unknown.
Immature. Unknown.
Planchonella sandwicensis.
Oahu. Only known from the Waianae Mountains.
Named for Karl Magnacca, a talented biologist who contributed several specimens for this study (noun in the genitive case).
Currently only known from males, it may belong in the reticulata species group based on fore wing characters and paramere shape, but is currently unplaced.
Holotype male (slide mounted), Mokuleia Forest Reserve, Pahole, N Waianae Mnts, Oahu, USA, N21.53208, W-158.1786, ex Planchonella sandwicensis, 6 July 2014, “Hi74-14” D. Percy leg. (BMNH). Paratypes (slide mounted) 2m, as for holotype (BMNH). Other material: 1m, Puu Hapapa, Central Waianae Mnts, Oahu, USA, N21.4666, W-158.1029, ex Planchonella sandwicensis, 17 May 2014, “KM14-14” K. Magnacca leg. (BMNH).
All Swezeyana species are hosted by a single, endemic Hawaiian host plant, Planchonella sandwicensis (Sapotaceae); and this long lived woody plant is distributed across all major islands in the archipelago. Co-occurrence of two or more Swezeyana species collected from the same tree are known for at least four islands, Kauai, Oahu, Maui, and Hawaii (
Supporting the possibility of sympatric speciation is the single island endemism of most Swezeyana species that are known to co-occur, as well as some support from the molecular data. Due to a lack of backbone resolution in the phylogeny based on the two region DNA barcode data, short branches and variably supported nodes for the three putative same island species pairs, indicate these two gene regions are most effective for confirmation of species assignment, but less effective for resolving relationships between species. Nevertheless, of the three co-occurring species pairs, those on Oahu and Hawaii (S. atra and S. oahuensis on Oahu; and S. hawaiiensis and S. rubra on Hawaii) represent putative sister pairs, while a species pair on Kauai (S. reticulata and S. tentaculata) provides an unequivocal example (with stronger phylogenetic support likely due to a more recent speciation event) for a sister taxon relationship for these co-occurring species. The Kauai species pair have repeatedly been found co-occurring on the same individual leaves and both species are likely endemic to Kauai. Therefore, in the Kauai example, geography and molecular data provide strong evidence for diversification in sympatry.
The Hawaiian psyllids in the genus Pariaconus that feed on Metrosideros polymorpha also show similar evidence of divergence in sympatry, but these Metrosideros-feeding species often exhibit clear niche partitioning of the host species by different galling and non-galling biologies and/or occupation of different parts of the plant and/or different plant morphotypes (
Other than the sister taxon pair on Kauai, all Swezeyana species sampled for the DNA analysis are highly divergent from one another, and the lack of backbone resolution in the genus suggests there may have been a modest but rapid early radiation after colonization of the Hawaiian Islands, with little more recent divergence. Alternatively, more recent divergence events may have been obscured by extinction, or not yet discovered. Molecular divergence provides a comparison with other Hawaiian psyllid lineages, and suggests that Swezeyana, is another relatively old endemic genus in the Hawaiian Islands (
Recognition of the two species groups in Swezeyana (elongagena group and reticulata group) is based primarily on the strikingly different structures of the female terminalia. This morphology is characterized by different development of the apodemes giving rise to distinct endoskeletons in the two species groups, and these different female terminalia structures imply traits related to oviposition that could be important in diversification, although the ovipositor itself is more or less invariant. However, because taxa in different species group, and taxa in the same species group, co-occur on the same individual plants, seemingly without any observable niche partitioning, it is particularly difficult to understand what may have initially driven this striking differentiation in female terminalia structure. Although the two species groups are recovered in the molecular topology, there is little to no bootstrap support for the elongagena group, emphasizing again the effectiveness of these barcode regions for identifying individuals to species but not for providing resolution at deeper nodes for higher classification. Nevertheless, the molecular data does serve to emphasise that the presence and number of cross veins and wing patterning varies within species groups. For instance, the two species with the greatest degree of wing patterning, as well as highest number of cross veins between Rs and the wing margin, S. rubra and S. tentaculata, are in different species groups, elongagena group and reticulata group respectively, and the more patterned wings with a greater number of cross veins appear to have resulted from convergence in these characteristics. A wing type with numerous cross veins may be the ancestral state, but at present more sampling and analysis are required to test this hypothesis. Some of the fore wing and other unusual morphological traits in the genus may point to different dimensions of niche specialization among species. For instance, the often striking reddish to pink colouration/highlights found in many Swezeyana may provide camouflage against the rusty coloured trichomes on the host plant leaves, and variation in body and wing colouration may be involved in different strategies for predator avoidance or mate selection; the notably thickened anterior fore wing margin is another unusual characteristic of the genus that is as yet unexplained, but may play a role in acoustic communication (
Swezeyana species are not generally abundant, for instance in comparison to some of the Metrosideros-feeding Pariaconus (
The taxonomic affiliations of Swezeyana to other genera within the family Triozidae is uncertain due to the lack of a robust phylogenetic framework for the family, but it is worth noting that the immatures of Hemischizocranium, which are also free-living on the leaf surface, have a distinct medial (anterior-posterior) linear row of small dorsal tubercles (
Financial support that assisted in fieldwork is gratefully acknowledged from a Leverhulme Trust funded postdoctoral studentship [SAS/2000/0], a Smithsonian Institution Postdoctoral Fellowship (2004–2005), and an NSF Dimensions of Biodiversity award [DEB 1241253] to the University of California, Berkeley. Molecular sequencing was partly supported by a Smithsonian Institution Fellowship, and the Natural History Museum, London Molecular Taxonomy Fund (DIF). I am grateful to Jon Giffin, Karl Magnacca, and Steve Montgomery for providing assistance in the field, and to Betsy Gagné for facilitation and logistical support.