Quoc Toan Phan

As part of an ongoing study of Mirinae in Vietnam, additional data on the so-called Lygus complex are presented. Five genera, Apolygopsis Yasunaga, Schwartz & Chérot, 2002, Apolygus China, 1941, Diognetus Distant, 1904, Euphorbialygus Yasunaga, 2024, and Himalisundacoris Yasunaga, 2024 are newly recorded from Vietnam. Four species are described herein as new: Apolygus namyatovae Kim & Jung, sp. nov ., Diognetus schwartzi Kim & Jung, sp. nov ., Euphorbialygus kontumensis Kim & Jung, sp. nov ., and Himalisundacoris yasunagai Kim & Jung, sp. nov . In addition, three species, Anthophilolygus alaneylesi Yasunaga, Schwartz & Chérot, 2018, Apolygopsis nigra (Poppius, 1915), and Prolygus nigriclavus (Poppius, 1915) are newly recorded from Vietnam. Detailed descriptions and diagnoses based on external and genitalic morphology are provided for each species, together with detailed illustrations.

Heliogomphus retroflexus (Ris, 1912) is transferred to the genus Microgomphus Selys, 1858 and is herein recognised as M. retroflexus (Ris, 1912), comb. nov., based on evidence from adult and larval morphology and molecular data. New distribution records are reported. The molecular analyses also indicate that the current generic limits of Microgomphus warrant further reassessment. Distribution patterns, sympatry, and knowledge gaps within the genus, as well as their implications for the classification of Oriental gomphids, are also discussed.

The larva of the Philippine endemic Pandanobasis cantuga (Needham & Gyger, 1939) is described and illustrated for the first time based on reared specimens from Mindanao and Dinagat islands, representing the first known larva of the genus. Diagnostic characters, notes on its habitat, biology, conservation and comparisons with other Malesian—Pacific Teinobasini are provided.

The spartaeine genus Neobrettus Wanless, 1984, is reviewed based on newly collected material from Vietnam. Two species, N. phui Żabka, 1985 syn. nov. from Vietnam and N. nangalisagus Barrion, 2001 syn. nov. from the Philippines are recognized as junior synonyms of N. tibialis (Prószyński, 1978). Additionally, the species Gelotia syringopalpis Wanless, 1984 is recorded from Vietnam for the first time, representing the fourth species of the genus known from the country.

Updated distribution and keys to the males and females of all known Copera in Southeast Asia are provided with description of C. phanthanhhaii sp. nov. from Vietnam and Thailand (holotype ♂: Dong Hoi City, Quang Tri Province, Vietnam (17.379333°N, 106.482806°E, 163 m elevation). The new species differs from C. vittata (Selys, 1863) by having tibiae of middle and hind legs distinctly broadened in male and the shape of posterior process on the female’s prothorax.

The larva of Pornothemis starrei Lieftinck, 1948 is described for the first time based on material from Singapore reared to adulthood, representing the first larval description of the genus Pornothemis Krüger, 1902. The larva is characterized by a unique combination of morphological features, including a distinctive arrangement and number of premental setae and palpal setae, strongly developed middorsal spines on S3–9, and posterolateral spines on S7–9. Comparisons with other Southeast Asian genera of Libellulinae indicate that the larva is readily distinguishable from all described congeners. Additional notes on habitat, distribution, and the taxonomic status of the genus are provided. This study increases our knowledge of larval diversity within Libellulinae and contributes to a better understanding of the morphology and distribution of this poorly known Southeast Asian dragonfly genus.

The drassodine ground spider genus Megamyrmaekion Reuss, 1834 is recorded from Vietnam for the first time as a result of the following new combinations here proposed: M. luridum (O. Pickard-Cambridge, 1874) comb. nov., ex Drassodes Westring, 1851, and M. vickyae (Sherwood, Marusik, Sharp & Ashmole, 2023) comb. nov., ex Australoechemus Schmidt & Piepho, 1994. Detailed redescriptions and illustrations of the male and female of M. luridum comb. nov., from Vietnam are provided. Additionally, A. celer Schmidt & Piepho, 1994 syn. nov., is recognized as a junior synonym of M. caudatum Reuss, 1834. Drassus tarrhunensis Karsch, 1881 is removed from the synonymy of M. caudatum and provisionally transferred to the genus Megamyrmaekion as M. tarrhunense (Karsch, 1881) comb. nov.

Drepanosticta minhanhiana sp. nov. (holotype ♂: 15.26416° N, 121.35115° E; 69 m a.s.l.; deposited at Cavite State University, Philippines) is described from Luzon Island, the Philippines, based on specimens of both sexes. The new species can be distinguished from its congeners by the differential characters of the male prothorax and by the structure of anal appendages. Additional descriptive notes, as well as detailed morphological photographs and illustrations of both the male and female of D. halterata (Brauer, 1868), are also provided.

Heteronaias Needham & Gyger, 1937 is a monotypic genus represented solely by Heteronaias heterodoxa (Selys, 1878), a poorly documented corduliid. Based on reared specimens from Luzon, Philippines, we provide a detailed larval description, notes on adult morphology, and distributional data. Adult characters, particularly the vesica spermalis of male and female terminalia, are redescribed and illustrated. The larva is distinguished by a flattened body, 9–13 premental setae, 8–11 palpal setae, a poorly developed ligula, middorsal protuberances on abdominal segments 6–10, and a distinct episternal apophysis. Comparative analysis with Asian corduliid genera highlights diagnostic larval features valuable for taxonomy and phylogenetic studies. Larvae inhabit shaded forest streams and emerge on rock surfaces, showing rheophilic adaptations comparable to those of Zygonyx Selys in Hagen, 1867 (Libellulidae). Distributional records confirm that H. heterodoxa is endemic to the Philippines.