Pariaconus crassiorcalix Percy

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 : 56-59

Pariaconus crassiorcalix Percy sp. n. Figures 26, 49 K–R

Adult colour.

General body colour pale yellow to orange (Fig. 26G). Fore wing membrane clear or slightly fuscous.

Adult structure.

Fore wing apex bluntly acute; surface spinules dispersed, usually present in all cells but may be limited or absent; short setae on margins and veins (Fig. 26A). Antennae short (length av. 0.70; ratio AL:HW av. 1.42); genal processes short (ratio VL:GP av. 2.92) and rounded apically; medium long setae on vertex and short setae on thorax; distal proboscis segment short (av. length 0.09); hind tibia slender, length subequal to head width (ratio HW:HT av. 1.02) (Fig. 26 B–F). Male terminalia (Fig. 26 H–I): paramere shorter than proctiger (ratio MP:PL av. 1.15), broad and parallel-sided before tapering to an elongate neck below a somewhat flat-topped apex with anteriorly directed hook; distal aedeagus segment length subequal to paramere (ratio PL:AEL av. 0.98) with base slightly angular and inflated, and a moderately large hooked apex (ratio AEL:AELH av. 2.5). Female terminalia (Fig. 26 J–K): proctiger dorsal surface more or less straight, apex bluntly acute, anal ring long (ratio FP:RL av. 3.97); subgenital plate with slight medial bulge ventrally, bluntly acute apically; ovipositor apex with reduced serrations (2-3 above, 2-3 below), valvulae dorsalis not strongly convex dorsally.

Egg.

Light brown, short, slightly sinusoidal, surface granular in appearance, no microsculpturing, short pedicel 1/4 length from base, tail bulbous (Fig. 26L).

Immature.

Colour and structure: Brown to orange-brown dorsally, cream to orange ventrally. 5th instar: Broadly ovoid in outline (but narrower than Pariaconus caulicalix ), wing buds only slightly protruding with distinct humeral lobes (Fig. 49 K–L). Dorsal surface with round tubercle like scales (as opposed to ridges in Pariaconus caulicalix ) (Fig. 49N). Tarsi with medium large claws (as wide as arolia) (Fig. 49M). Circumanal ring moderately wide (CPW:RW av. 5.00), shallowly v-shaped, with a single row of elongate cells (Fig. 49K). Chaetotaxy: 5th instar: Continuous marginal ring of blunt sectasetae (Fig. 49O). Dorsal surface with intermittent minute simple setae. 1st instar (similar to that illustrated for Pariaconus caulicalix ): Margin with broad blunt sectasetae (10 pairs anterior margin of head, 1 pair postocular, 1 pair each wing bud, 10 pairs abdominal), and with distinct arrangement of acutely pointed small sectasetae dorsally (2-4 pairs on head, 2-4 pairs on thorax, 2-5 pairs on the abdomen), mostly lost by 3rd-4th instars, but minute sectasetae are scattered dorsally in some older instars.

Host plant notes.

Only known from one locality where it galls densely pubescent bog morphotypes.

Island.

Kauai.

Distribution notes.

Known only from Alakai Swamp, Kokee State Park.

Biology.

Forms thick-walled cup galls on stems, galls are often clustered together, with one individual per gall chamber (Fig. 49 P–R). The depression forming the cup gall is not as deep as for Pariaconus caulicalix , the cup walls are much thicker and the gall tissue is typically dark red or orange-brown. The immature is lodged tightly in the base of the cup with the sclerotized dorsal surface forming a plug under which is the soft unsclerotized body (Fig. 49R). The different structure of the dorsal surface, scaly in Pariaconus crassiorcalix and ridged in Pariaconus caulicalix , may be related to adaptation to different moisture levels, with Pariaconus crassiorcalix found in more humid, wet bog habitat.

Etymology.

The name refers to the gall type which is a thick (crassior)-walled and cup (calix)-shaped cambial outgrowth on the plant stems (adjective in the nominative singular).

Comments.

This species is a sister taxon to the other known cup gall maker, Pariaconus caulicalix , and, together with Pariaconus elegans , Pariaconus gagneae , Pariaconus haumea , and Pariaconus lehua , for which biologies are currently unknown, may constitute a sub-clade of cup gallers. A similar type of thick walled cup gall (Fig. 48 N–O, referred to as "a raised button gall on the stem", Russell Messing pers. comm.) is produced by an immature with long waxy dorsal filaments, which may be the immature of one of the described species here, or an as yet undescribed species.

Type material.

Holotype male (slide mounted, BMNH). See Table 2 for details of type and other material examined for this study.