Revision of the Hawaiian psyllid genus Swezeyana, with descriptions of seven new species (Hemiptera, Psylloidea, Triozidae)

Abstract

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.

Acizzia errabunda sp. nov. and Ctenarytaina insularis sp. nov.: Descriptions of two new species of psyllids (Hemiptera: Psylloidea) discovered on exotic host plants in New Zealand

“…Inevitably, new psyllid species are being described every year. For example, from the Hawaiian Islands 36 new species have been described in the genus Pariaconus [16] and seven in the genus Swezeyana [20], while 22 new species in the genera Acizzia , Myotrioza and Trioza have been described from Australia [14, 21].…”

Origins of the central Macaronesian psyllid lineages (Hemiptera; Psylloidea) with characterization of a new island radiation on endemic Convolvulus floridus (Convolvulaceae) in the Canary Islands

“…Similarly, successful colonization and establishment will depend on locating both familiar and unoccupied host plants [25,39]. Examples of phytophagous insect species radiations occurring on a single host plant species, particularly in sympatry, are rare [40][41][42]. A number of psyllid genera in continental regions are known to have multiple species occurring on the same host plant species (e.g., Arytainilla, Bactericera, Cacopsylla, Calophya, Mitrapsylla, Queiroziella).…”

Resolving an 87-year-old taxonomical curiosity with the description of Psylla frodobagginsi sp. nov. (Hemiptera: Sternorrhyncha: Psyllidae), a second distinct Psylla species on the New Zealand endemic plant kōwhai

“…This can be facilitated by the continuous updating of psyllid taxonomic diversity and distribution. Good examples tackling Australasia and the Pacific, as a hot spot for biodiversity of the Psylloidea [1, 2], include the most recent works focusing on Australia [6, 7], New Zealand [3, 8, 9], Cook Islands [10] and Hawaii [11, 12]. Expediting this appraisal has been inclusion of molecular phylogenetic studies to enable a better understanding of this superfamily’s evolutionary history (e.g.…”