The Essential Role of Taxonomic Expertise in the Creation of DNA Databases for the Identification and Delimitation of Southeast Asian Ambrosia Beetle Species (Curculionidae: Scolytinae: Xyleborini)

DNA holds great potential for species identification and efforts to create a DNA database of all animals and plants currently contains >7.5 million sequences representing ~300,000 species. This promise of a universally applicable identification tool suggests that morphologically based tools and taxonomists will soon not have utility. Here we demonstrate that DNA-based identification is not reliable without the contributions of taxonomic experts. We use ambrosia beetles (Xyleborini), which are known for great diversity as well as global invasions and damage, as a test case. Recent xyleborine introductions have caused major economic and ecological losses, thus timely species identifications of new invaders are necessary. This need is hampered by a paucity of identification tools and a fauna that is only moderately documented. To help alleviate deficiencies in their identification, we created COI and CAD DNA barcode databases (490 and 429 specimens), representing over half of the known fauna of Southeast Asia (165/316 species). Taxonomic experts identified species based on original descriptions and type specimens. Tree, distance, and iterative methods were used to assess the identification and delimitation of species. High intra- and interspecific COI distances were observed for congeneric species and attributed to the beetle's inbreeding system. Neither of the two markers provided 100% identification success but with the neighbor-joining tree-based method, 80% of species were identified by both genes. As for species delimitation, an obvious barcode gap between intra- and interspecific differences was not observed. Correspondence between distance-based groups and morphology-based species was poor. In a demonstration of iterative taxonomy, we constructed parsimony-based phylogenies using COI and CAD sequences for two genera. Although not all clades were resolved or supported, we provided better explanations for species boundaries in light of morphological and DNA sequence differences. Confident species identifications demonstrated 10–12% COI and/or >2–3% CAD. Involvement of taxonomic experts from the start of this project was essential for the creation of a stable foundation for the DNA identification of xyleborine species. In general, their role in DNA barcoding cannot be underestimated and is further discussed.publishedVersio

Bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) infesting mango trees (Mangifera indica L.) in Southern Thailand, with two new species recorded for Thailand

Fifteen species of ambrosia beetles and two bark beetle belonging to the curculionid subfamilies Scolytinae andPlatypodinae (Coleoptera: Curculionidae) were collected from three infested mango trees (Mangifera indica L.) in theresearch orchards of the Faculty of Natural Resources, Prince of Songkla University, Songkhla Province. Two species,Arixyleborus grandis (Schedl) and Xyleborinus sculptilis (Schedl), are recorded for the first time in Thailand

Cnestus quadrispinosus, a new species of xyleborine ambrosia beetle from Thailand and Borneo (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

A new species, Cnestus quadrispinosus, is described from Thailand, Brunei Darussalam, and East Malaysia (Sabah). It is compared to three related species of Cnestus which lack a mycangial tuft of hairs on the pronotum, and have an impressed elytral declivity

Tricosa uniseriata, a new species of xyleborine ambrosia beetle from Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

A new species, Tricosa uniseriata sp. nov., is described here. A list of Tricosa species found in Thailand with distributions and an updated key to Tricosa are also provided

New species and newly recorded species of Anisandrus Ferrari, 1867 ambrosia beetles from Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

Five new species, Anisandrus montanus sp. nov., A. phithakpa sp. nov., A. tanaosi sp. nov., A. triton sp. nov., and A. uniseriatus sp. nov. are described from Thailand. Anisandrus carinensis (Eggers, 1923) is reported from Thailand for the first time and A. apicalis is removed from the Thai fauna. With the inclusion of the species described and recorded here, the diversity of Anisandrus is increased to 40 species, of which 11 occur in Thailand. A synoptic list and a key to the Anisandrus of Thailand are presented

Eggersanthus Sittichaya & Smith gen. nov., a new Oriental ambrosia beetle genus (Coleoptera: Curculionidae: Scolytinae: Xyleborini)

Sittichaya, Wisut, Smith, Sarah M. (2020): Eggersanthus Sittichaya & Smith gen. nov., a new Oriental ambrosia beetle genus (Coleoptera: Curculionidae: Scolytinae: Xyleborini). Zootaxa 4779 (2): 282-288, DOI: https://doi.org/10.11646/zootaxa.4779.2.

Review of the millipede genus Malayorthomorpha Mršić, 1996 (Diplopoda, Polydesmida, Paradoxosomatidae), with descriptions of two new species from Thailand and a key to its species

The millipede genus Malayorthomorpha Mršić, 1996, so far monospecific and previously known only from Park Belum, Perak State, northern Malaysia, is recorded from a mountain in Betong District, Yala Province, southern Thailand for the first time, being represented there by two new species: M. halabala sp. nov. and M. hulutbeeda sp. nov. Both new species are found to occur syntopically and can be assumed as narrowly endemic to the Titiwangsa Mountain Range which begins in southern Thailand, crosses the Malaysian border, and extends into east and west coast regions of the Malay Peninsula. In addition, the generic diagnosis is slightly updated, and a key to all three species is provided

The Oriental genera of Xyloperthini (Coleoptera: Bostrichidae: Bostrichinae), with a new genus and species from Thailand, and a key to the genera

We describe a new genus, Infrantenna gen. nov. and a new species Infrantenna fissilis gen. et sp. nov., from Thailand and briefly review the Oriental genera currently placed in the tribe Xyloperthini Lesne, 1921. A key to the Oriental genera of Xyloperthini is provided.</p

The Oriental genera of Xyloperthini (Coleoptera: Bostrichidae: Bostrichinae), with a new genus and species from Thailand, and a key to the genera

We describe a new genus, Infrantenna gen. nov. and a new species Infrantenna fissilis gen. et sp. nov., from Thailand and briefly review the Oriental genera currently placed in the tribe Xyloperthini Lesne, 1921. A key to the Oriental genera of Xyloperthini is provided