T. iban sp. nov. is described from the Lanjak Entimau Wildlife Sanctuary in Sarawak, Malaysian Borneo. Both sexes can be distinguished from all other species of Telosticta by the form of the antehumeral markings.
Onychogomphus marijanmatoki is described from a male from Gunung Mulu National Park, Miri Division, Sarawak, Malaysian Borneo. One of only two onychogomphine species known from Borneo, it differs from all others of the group in characters of the genital ligula and terminal appendages.
Coeliccia junis sp. nov. (holotype male from Borneo, Sarawak, Bintulu Division, Planted Forest Project, Bukit Mina Wildlife Corridor, "Day 4" stream near Bukit Nyegoh and Bukit Jugam, near small brown water pool, 10 viii 2018, deposited in the Naturalis Biodiversity Center, Leiden, the Netherlands) and Coeliccia roberti sp. nov. (holotype male from Borneo, Sarawak, Miri Division, Lambir Hills National Park, small stream on Oil Well Trail, 22 iv 2011, deposited in the Naturalis Biodiversity Center, Leiden, the Netherlands) are described from Borneo. Both new species belong to the Coeliccia membranipes-group and bring the number of named species known from the group from Borneo to nine and the total number of named species from Borneo currently placed in Coeliccia to 15. Coeliccia junis is only known from a small area in Sarawak, C. roberti is also known from Brunei. Both species are considered likely to be closely allied with C. macrostigma Laidlaw.
Coeliccia matok sp. nov. (holotype male from Borneo, Sarawak, Samarahan Division, peat swamp forest at old UNIMAS campus, 25 ii 2008, to be deposited in BMNH) and Coeliccia paludensis sp. nov. (holotype male from Borneo, Kalimantan Tengah, peat swamp forest in ex Mega Rice Project Block E, 18 vi 2012, in RMNH) are described from Borneo. The two new species are apparently confined to peat swamp forest (C. paludensis) or largely confined to peat swamp forest and related forest formations (C. matok). Coeliccia macrostigma Laidlaw is redescribed and all available information on it is summarised. Additional terminology for characters of the prothorax in Coeliccia species is introduced. Distribution maps are given for all three species considered.
Amphicnemis rigiketit sp. nov. is described from southwestern Sarawak (holotype ♂ in forest around stream, near road from Kota Samarahan to Siburan, Samarahan Division, Sarawak, Malaysian Borneo, 21 ii 2018, deposited in the Natural History Museum, London). The new species is allied to A. remiger Laidlaw, 1912. The female of A. remiger is described for the first time and a description of the male from a fresh specimen is provided along with notes on variation.
The final stadium larva of Onychargia atrocyana Selys, 1865, is described and illustrated based on two female specimens collected at Gunung Mulu National Park, Sarawak, East Malaysia. The larvae were identified by matching the mitochondrial marker COI with that of known adult specimens from Gunung Mulu, Bintulu and Kuching in Sarawak and from Pahang state in West Malaysia. The specimens presented close matches with all adults in this gene. As O. atrocyana is a taxonomically isolated species with no close congeners in Borneo the determination is beyond doubt. O. atrocyana is the only member of the Onychargiinae for which the larva is known. It is compared with the known larvae of other platycnemidid subfamilies, and the possible significance of larval morphology in higher classification of the group is discussed.
M. megabinluyog spec. nov. is described from a location in Brunei on the island of Borneo. Additional illustrations of its sister species M. astamii are provided.
Phaenandrogomphus safei is described from a male from the Kalabakan Forest Reserve, Sabah, Malaysian Borneo. It is the first species of Phaenandrogomphus to be recorded from Borneo. Onychogomphus treadawayi, known from Busuanga Island in the Palawan region of the Philippines, is transferred to Phaenandrogomphus.
Prodasineura yulan is described from a male from Maludam National Park, Betong Division, Sarawak, Malaysian Borneo. It is allied to Prodasineura interrupta.
Megalogomphus sumatranus (Krüger, 1899) and its allies in Sundaland are reviewed. The accessory genitalia of the males of this genus, hardly considered previously, are found to be taxonomically informative. The taxon from Borneo previously treated as M. sumatranus is described from both sexes as M. buddi sp. nov. (holotype ♂ Sungai Datai, Nanga Bloh, Lanjak Entimau Wildlife Sanctuary, Kapit Division, Sarawak, Malaysia, 22 viii 2013, leg. J. anak Awan M. anak Adau; deposited at the Naturalis Biodiversity Center, Leiden, the Netherlands). Megalogomphus borneensis (Laidlaw, 1914), described as a subspecies of M. icterops (Martin, 1903) and subsequently relegated to the synonymy of that species, is considered to be a distinct species. Megalogomphus icterops is however considered to be a junior synonym of M. sumatranus. A re-description of the holotype of Megalogomphus borneensis is provided as is the first description of the female. Descriptive notes with illustrations of Megalogomphus sumatranus are given.
Yunnanosticta gen. nov. in the platystictid subfamily Sinostictinae is described from Yunnan, China. The genotype is Yunnanosticta wilsoni sp. nov., described here (holotype ♂ from Tongbiguan, Yingjiang County, Dehong Dai Jingpo Autonomous Prefecture, Yunnan, China, 23 vi 2015, leg. H.M. Zhang, to be deposited in the Natural History Museum, London). Yunnanosticta cyaneocollaris sp. nov. (holotype ♂ from Tongbiguan, Yingjiang County, Dehong Dai Jingpo Autonomous Prefecture, Yunnan, China, 23 vi 2015, leg. H.M. Zhang, to be deposited in the Natural History Museum, London) is also described.
Drepanosticta adenani sp. nov. (holotype ♂, from a tributary of Sungai Jela, Nanga Segerak area, Lanjak Entimau Wildlife Sanctuary, Sri Aman Division, Sarawak, Malaysian Borneo, 18 vii 2016, deposited in the Natural History Museum, London) is described from both sexes.
Podolestes parvus sp. nov. is described and illustrated from both sexes from Sarawak, Malaysian Borneo (holotype male Maludam National Park, Betong Division, Sarawak, 10 vii 2012, deposited in RMNH). The new species is closest to P. atomarius Lieftinck, 1950 and is the smallest species yet known in its genus. A full set illustrations of P. atomarius is provided for comparison. [Species Zoobank URL: urn:lsid:zoobank.org:act:EE7ABAB0-8683-4D25-8A2C-76977931FD87].
Species of Devadatta from Borneo are studied using both morphological and molecular methods. As well as D. podolestoides Laidlaw, four new species are recognised from the island: D. aran spec. nov. (holotype ♂, from Pulong Tau National Park, Miri division, Sarawak, Malaysia, deposited in RMNH), D. clavicauda spec. nov. (holotype ♂, from Bukit Mina, Bukit Mina Wildlife Corridor, Sarawak Planted Forest Project, Bintulu division, Sarawak, Malaysia, deposited in RMNH), D. somoh spec. nov. (holotype ♂, from the Sungai Kahei area, Ulu Balui, Kapit division, Sarawak, Malaysia, deposited in RMNH) and D. tanduk spec. nov. (holotype ♂, from Poring Hot Springs, Kinabalu National Park, West Coast division, Sabah, Malaysia, deposited in RMNH). The Philippine taxon D. basilanensis Laidlaw is considered a good species rather than a subspecies of D. podolestoides. The Bornean species plus D. basilanensis are provisionally considered to form a species group, the podolestoides-group, within Devadatta. The species of the podolestoides-group are so similar in morphology and colouration that they are close to truly cryptic species. Two species appear to exhibit character displacement where their ranges overlap with other Devadatta species. A molecular analysis using four markers (COI, 16S, ITS and 28S) is presented. This analysis includes specimens of all species from the podolestoides-group and two Devadatta species from mainland Asia.
The Sundaland species of the genus Dysphaea were studied using molecular and morphological methods. Four species are recognized: D. dimidiata Selys, D. lugens Selys, D. ulu spec. nov. (holotype ♂, from Borneo, Sarawak, Miri division, Upper Baram, Sungai Pejelai, Ulu Moh, 24 viii 2014; deposited in RMNH) and D. vanida spec. nov. (holotype ♂, from Thailand, Ranong province, Khlong Nakha, Khlong Bang Man, 12-13 v 1999; deposited in RMNH). The four species are described and illustrated for both sexes, with keys provided. The type specimens of the four Dysphaea taxa named by E. de Selys Longchamps, i.e. dimidiata, limbata, semilimbata and lugens, were studied and their taxonomic status is discussed. Lectotypes are designated for D. dimidiata and D. limbata. D. dimidiata is recorded from Palawan (the Philippines) for the first time. A molecular analysis using three markers (COI, 16S and 28S) is presented. This includes specimens of three Sundaland species of the genus (D. lugens missing) and two congeners from other regions (D. basi-tincta and D. gloriosa). Notes and photographs of the male holotype of D. walli Fraser (from Maymyo, Burma) are provided.
Drepanosticta emtrai sp. nov. is described from Vietnam (holotype male Ha Tinh Province, 9 vi 2015, to be deposited in RMNH). The new species is allied to D. carmichaeli (Laidlaw, 1915) and a number of other species of Drepanosticta including D. vietnamica Asahina, 1997. New illustrations of the paratype of D. vietnamica are provided and the species is discussed. The Drepanosticta carmichaeli-group, to which the above mentioned species belong, is defined and discussed.
Coeliccia erici Laidlaw, 1917 is re-described and illustrated for both sexes; its taxonomic history and the confusion surrounding it is discussed. Coeliccia kimurai Asahina, 1990 is shown to be a junior synonym of C. erici. Coelicca sameerae sp. nov. (holotype ♂, small stream near Sungai Lasir, Tasik Kenyir, Terengganu, Malaysia, deposited in the Natural History Museum, London) is described from both sexes from Peninsular Malaysia; this species had been confused with C. erici until now. A remark on the status of Coeliccia simillima Laidlaw, 1917 is made.
Protosticta joepani sp. nov. is described from Malaysian Borneo (holotype male Bario, Kelabit Highlands, Miri Division, Sarawak, Malaysia, deposited in the Naturalis Biodiversity Center, Leiden). It is the sister species of P. kinabaluensis Laidlaw, 1915; some descriptive notes and a set of illustrations are provided of the latter species. A COI gene tree for both species is provided. The placement of both P. joepani and P. kinabaluensis is discussed, but although it is very unlikely that they belong in Protosticta sensu stricto, the issue is left open here.
Telosticta fugispinosa sp. nov. (holotype male, from Borneo, Sabah, West Coast division, Crocker Range National Park, Inobong, Kimamabang waterfall stream system, 21 ix 2012, deposited in RMNH) is described from Kinabalu National Park and Crocker Range National Park in Sabah, Malaysian Borneo. It is distinguished from all other species of Telosticta by the form of the male anal appendages.
Drepanosticta rahmani sp. nov. (holotype ♂, steep tributary to stream in hills between Baling and Gulai, north west Kedah, Malaysia, 15 xi 2016, leg. R.A. Dow, to be deposited in the Natural History Museum, London) is described from both sexes.