Pariaconus iolani (Kirkaldy, 1902) Kirkaldy, 1902

Percy, Diana M., 2017, Making the most of your host: the Metrosideros-feeding psyllids (Hemiptera, Psylloidea) of the Hawaiian Islands, ZooKeys 649, pp. 1-163 : 49-50

Pariaconus iolani (Kirkaldy, 1902) comb. n. Figure 21

Trioza iolani Kirkaldy, 1902: 114 in part (Kauai specimens, nec Oahu specimens), type designated by lectotypification in 1908: 206; non Trioza iolani Crawford, 1918, nec Zimmerman, 1948.

Trioza kauaiensis Crawford, 1925: 29, syn. n.

Adult colour.

General body colour green, yellow-green or yellow-orange, often with brown on legs, thorax and abdomen. Females may have a darker abdomen due to darkly pigmented egg load. Fore wing membrane clear.

Adult structure.

Fore wing apex rounded; surface spinules sparsely distributed, usually in all cells except limited or absent from cell r1; long setae on margins and particularly dense on the ventral margin, sparse long setae on veins (Fig. 21A, D). Antennae long (av. length 1.33; ratio AL:HW av. 1.85); genal processes length short-medium and bluntly acute (ratio VL:GP av. 2.04); medium to long setae on vertex and thorax; distal proboscis segment short (av. length 0.09); hind tibia thick, length shorter or subequal to head width (ratio HW:HT av. 0.95) (Fig. 21 B–C, F). Male terminalia (Fig. 21E, G–I, K–L): paramere length subequal to proctiger (ratio MP:PL av. 1.06), paramere extremely broad, with a prominent central ridge and posterior bulge or “shoulder”, apex directed anteriorly; subgenital plate extending posteriorly to give a somewhat triangular rather than rounded shape; distal aedeagus segment length subequal to paramere (ratio PL:AEL av. 0.93) with base rounded and slightly inflated, and a large hooked apex (ratio AEL:AELH av. 2.20). Female terminalia (Fig. 21J, M–O): proctiger short, dorsal surface straight, apex constricted in dorsal view and bluntly acute, anal ring short (ratio FP:RL av. 4.17); subgenital plate strikingly concave ventrally and apex truncate (ratio FP:FSP av. 1.12); ovipositor apex with distinct serrations (3 above, 4 below), valvulae dorsalis not strongly convex dorsally.

Egg.

Mid- to light brown, elongate oval, with longitudinal medial suture entire length of egg (coffee bean-like), surface with microsculpturing and granular in appearance, extremely short pedicel 1/3 length from base, tail lacking (Fig. 21Q).

Immature.

Unknown.

Host plant notes.

Collected predominantly from glabrous and semi-pubescent morphotypes.

Island.

Kauai.

Distribution notes.

Collected in several locations in Kokee State Park, including Alakai, Kalalau and Nu Alolo.

Biology.

Based on phylogenetic closeness to Pariaconus hiiaka , and the large body size, this species may have a similar closed gall biology, but further study is required to confirm.

Comments.

The female lectotype (dry mounted, BMNH) has been examined and compared with the female syntype (dry mounted, BPBM) of Trioza kauaiensis Crawford, 1925. In publications after 1908, the name Trioza iolani has been almost exclusively associated with a common Oahu species (here designated Pariaconus oahuensis ). There is no way to avoid this unfortunate synonymization given the following circumstances: Kirkaldy (1902) referred to two specimens in his original description, one from Kauai and one from Oahu, but the two specimens are not from the same species. In the original description, he illustrates only the specimen from Kauai but does not publish a designated type. However, in 1908 he validly lectotypified the Kauai specimen: "The type was from Kauai", and this specimen also bears a hand written label (apparently in Kirkaldy’s handwriting), "male type" (though the lectotype is in fact female) (Fig. 21P). The name iolani must therefore be considered to apply to the Kauai specimen, rather than the Oahu specimen, and the Kauai specimen belongs to the same species as that described by Crawford in 1925 as Trioza kauaiensis . Kirkaldy probably had a relatively broad concept of psyllid species (not being a specialist in this group), and he may not have had a good understanding of psyllid morphology because both the specimens and the illustration accompanying the original description (Plate IV, Fig. 2; and shown here in Fig. 21P) are females, not males as Kirkaldy thought them to be. Kirkaldy’s other female specimen clearly fits the concept of Trioza iolani sensu Crawford (1918, 1925) and Zimmerman (1948). Neither Crawford nor Zimmerman appear to have examined the BMNH type material, and Crawford only examined additional material collected by Kirkaldy from Oahu. Nevertheless, Zimmerman (1948) correctly noted that the specimen from Kauai was the type for iolani , and with typical astuteness discerned, “… some confusion regarding the identity of this species. It is generally thought of as one of the commonest psyllids on Oahu, yet the holotype was designated as a Kauai specimen. Further study might reveal that the Oahu form is a distinct species from the Kauai form".

Two forms are recognized on Kauai (Fig. 21): form iolani (based on the type is more common, with paramere apex more extended and posterior shoulder rounded) (Fig. 21H), and form scapulus (with paramere apex short and distinctly extended posterior shoulder) (Fig. 21L). More specimens and an investigation of the biology is required to establish if these are distinct species.

Type material.

Lectotype, female (dry mounted, BMNH). Syntype, female (dry mounted, BPBM). See Table 2 for details of type and other material examined for this study.