Priesneria akestra, Mound, Laurence A. & Wells, Alice, 2015

Mound, Laurence A. & Wells, Alice, 2015, Endemics and adventives: Thysanoptera (Insecta) biodiversity of Norfolk, a tiny Pacific Island, Zootaxa 3964 (2), pp. 183-210 : 198-201

Priesneria akestra sp. n.

( Figs 21–26 )

The genus Priesneria currently includes five species, of which three (including the type species, P. kellyana Bagnall ) are from Australia, with one from Hawaii and the other from India. All of these species have the third antennal segment with a remarkable, sub-basal, shelf-like ridge ( Mound & Minaei 2007). Four of the five species have only two sense cones on the fourth antennal segment, whereas longistylosa Pitkin from Australia shares with the new species described here the condition of four sense cones on this segment. Similarly, four of the five species have the major setae on the head and pronotum with capitate apices, and only peronis Mound & Minaei has these setae pointed and rather short. The new species shares with longistylosus the character states of the antennal sense cones and also the slender form of antennal segment VIII, but it is unique in the genus in having the setae on the head and pronotum ( Figs 22, 25 ) exceptionally long and finely pointed. The biology is unknown, but like other members of the genus this species is probably predatory on other small arthropods.

Male microptera: Body light brown, tube and antennae darker; tarsi yellow, tibiae yellow with brown shadings; major setae all pale. Antennae 8-segmented ( Fig. 24 ), segment VIII long, slender and constricted at the base; segment III with prominent shelf-like thickening sub-basally, with 2 sense cones, IV with 4 sense cones. Head longer than wide, with cheeks surrounding compound eyes laterally, ocelli small; maxillary stylets retracted to eyes, less than one-fifth of head width apart medially, with distinct but weak maxillary bridge; vertex weakly sculptured only posterolaterally ( Fig. 22 ); postocular setae finely acute, longer than half of head width. Pronotum transverse ( Fig. 25 ), almost without sculpture, notopleural sutures complete; with 5 pairs of long, finely acute major setae. Fore tarsus inner apical margin with minute forward-pointing tooth. Basantra well developed, ferna transverse, mesopresternum complete but slender medially, metathoracic sterno-pleural sutures absent. Mesonotum ( Fig. 23 ) weakly sculptured, lateral setae long and acute; metanotum almost without sculpture medially; fore wing lobe with 3 long and finely acute setae. Pelta D-shaped ( Fig. 26 ); tergites II–VII each with 2 pairs of small, fine and straight, wing-retaining setae, posteroangular setae very long; major setae on IX longer than tube, S2 as long as S1; anal setae longer than tube. Sternites without pore plates, marginal setae very long.

Measurements (holotype male in microns). Body length 1550. Head, length 160; width 135; po setae 90. Pronotum, length 110; width 190; major setae, am 60, aa 70, ml 100, epim 80, pa 85. Fore wing lobe 100, basal setae 65. Tergite VI lateral two pairs of setae 130. Tergite IX setae S1 160, S2 190. Tube, length 110, anal setae 200. Antennal segments III–VIII length 35, 47, 47, 42, 40, 35.

Female macroptera: Essentially similar to male in colour and structure; tergal wing-retaining setae larger and sigmoid, particularly posterior pairs on IV and V; fore wing weakly constricted medially, with only 2 duplicated cilia.

Measurements (paratype female in microns). Body length 1800. Head, length 185, width 155, postocular setae 80. Fore wing length 600. Tergite IX setae S1 185, S2 200. Tube length 110.

Specimens studied: Holotype male microptera, Norfolk Island, Palm Glen, beating twigs and Cordyline obtecta dead leaves, 30.xi.2014 (AW 14/66).

Paratype female macroptera, Norfolk Island, Mission Road Forest, from dead branches, 23.xii.2013 (LAM5878).

Psalidothrips taylori Mound & Walker ( Fig. 29 ): Described from Australia, where it is now known to be widespread, this species is also recorded widely from the North and South Islands of New Zealand. Adults are usually wingless, and the species is a fungus-feeder living at the base of grasses and in leaf-litter. Wingless specimens of both sexes, also fully winged females, were extracted from leaf litter under Olive trees at the edge of forest near Captain Cook Point in March 2014. One macropterous female of an undescribed species of Psalidothrips was taken from leaf-litter under Araucaria and Toona trees at Prince Philip Drive.

Sophiothrips martinae Mound & Tree ( Fig. 30 ): Wingless individuals of both sexes of this small, fungus-feeding thrips have been found on dead branches along the following tracks in the Norfolk Island National Park: Bird Rock, Bridle, and Palm Grove, also at Highland Lodge, 100 Acre Reserve, and on Mt Pitt. As with other members of this genus, there is considerable variation in body size, and the largest males have a small horn ventrally on the head between the bases of the antennae. It is a distinctively bicoloured species, largely yellow with brown spots on the head, pronotum and legs. In structure it is particularly similar to Sophiothrips aleurodisci , a dark brown species known only from New Zealand, but martinae is probably a Norfolk Island endemic.

Stephanothrips barretti Mound ( Fig. 31 ): Members of Stephanothrips are similar to those of Baenothrips in having the last abdominal segment exceptionally long, with long anal setae, but differ in having antennal segments III–V fused into a single unit ( Mound 1972). Single females of this wingless, fungus-feeding thrips have been taken on Norfolk Island at several localities in leaf-litter and on dead twigs. It is a widespread species in eastern Australia, but is usually taken in very low numbers.

Stephanothrips occidentalis Hood & Williams ( Fig. 32 ): Described from the Caribbean island of St Croix, this is the most common species in this genus. It is widespread around the tropics, including Queensland in Australia, living in leaf-litter and on dead branches ( Mound 1972). On Norfolk Island, females have been collected from dead leaves and dead branches at various sites across the island.

Strepterothrips species: Populations of an apparently undescribed species of this genus were found widely across the island, but particularly in the National Park at Red Road and on Bird Rock Track. It is a fungus-feeding species, and shares many character states with S. tuberculatus , a species that is common on dead branches across Australia and also occurs in New Zealand ( Mound & Ward 1971). More detailed studies on the various species of this genus in Australia are needed before the Norfolk Island populations can be described as a new species.

Yarnkothrips kolourus Mound & Walker : Described from New Zealand, this species has subsequently been found in Australia from Tasmania, south-eastern New South Wales, the Australian Capital Territory, and south of Darwin at Litchfield National Park in the Northern Territory. This species, the only named member of the genus, is unusual in its structure. The pronotum has incomplete notopleural sutures, the posteroangular setae are close to the epimeral setae, and the mesopresternum is largely fused to the mesoeusternum. Y. kolourus lives on dead branches, but as no more than one specimen has ever been taken at any one site it is probably a predator on other small arthropods. At least ten specimens were taken individually on Norfolk Island at various sites, including Captain Cook Point, Mt Pitt, Highland Lodge, Prince Philip Drive, and Bird Rock Track.

Figures

FIGURES 16 – 21. Phlaeothripidae species. (16) Bamboosiella cingulata; (17) Buffettithrips rauti; (18) Haplothrips gowdeyi; (19) Holoengythrips maynardae; (20) Hoplandrothrips leai, male; (21) Priesneria akestra.

FIGURES 22 – 26. Priesneria akestra sp. n. (22) Head; (23) Mesonotum and metanotum; (24) Antennal segments III – VIII; (25) Pronotum; (26) Pelta and tergite II.

FIGURES 27 – 32. Phlaeothripidae species. (27) Macrophthalmothrips neocaledonensis large male; (28) Plectrothrips australis; (29) Psalidothrips taylori apterous female; (30) Sophiothrips martinae male; (31) Stephanothrips barretti; (32) Stephanothrips occidentalis.