Evolution of endemism on a young tropical mountain.

Tropical mountains are hot spots of biodiversity and endemism, but the evolutionary origins of their unique biotas are poorly understood. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere. Here we investigate the evolutionary routes to endemism by sampling an entire tropical mountain biota on the 4,095-metre-high Mount Kinabalu in Sabah, East Malaysia. We discover that most of its unique biodiversity is younger than the mountain itself (6 million years), and comprises a mix of immigrant pre-adapted lineages and descendants from local lowland ancestors, although substantial shifts from lower to higher vegetation zones in this latter group were rare. These insights could improve forecasts of the likelihood of extinction and 'evolutionary rescue' in montane biodiversity hot spots under climate change scenarios.

Description of two final stadium platystictid larvae from Borneo, including that of Drepanosticta ?attala Lieftinck, identified using DNA barcoding (Odonata: Zygoptera: Platystictidae).

The final stadium larva of Drepanosticta ?attala Lieftinck, is described and illustrated based on a single male specimen collected at Kuala Belalong Field Studies Centre, Brunei. The larva was identified by matching the mitochondrial marker COI with that of known adult specimens. The larva presented a good match with both D. attala and D. barbatula Lieftinck in this gene, but as adults of only the former species had been collected at the locality, it is presumed more likely to be that species. Another, unidentified platystictid larva, Platystictidae A, collected at the same general locality is also described. The two larvae show significant differences from each other and from D. sundana Krüger, the only other Oriental region member of the family for which larval morphology is known. The three species are also compared with the larvae of the Neotropical genus Palaemnema, which they closely resemble, despite being currently placed in different subfamilies. Based on this known material, Oriental and Neotropical forms differ significantly in details of mandibular morphology, especially the armature of the molar field.

Telosticta iban sp. nov. from Sarawak (Odonata: Zygoptera: Platystictidae) .

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, a new species from Sarawak, Borneo (Odonata: Anisoptera: Gomphidae).

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.

Prodasineura yulan (Odonata: Zygoptera: Platycnemididae), a new species from Sarawak.

Prodasineura yulan is described from a male from Maludam National Park, Betong Division, Sarawak, Malaysian Borneo. It is allied to Prodasineura interrupta.

First description of the female of Coeliccia furcata Hämäläinen, 1986, with descriptive notes on males from Yunnan, China (Odonata: Zygoptera: Platycnemididae).

Coeliccia furcata Hämäläinen, 1986, an atypical species of Coeliccia Kirby, 1890 with bifurcated male cerci, had been known solely from the holotype male collected in Myanmar in 1938. In recent years the species has been rediscovered in Yunnan, China. The first description of the female is given, along with descriptive notes on the male and illustrations of both sexes, including fresh images of the holotype. Another of the unusual features of C. furcata is the extremely simple form of its penile organ, this is discussed and compared with other species from mainland Asia and Japan currently placed in Coeliccia and with a simple penile organ.

A review of the Drepanosticta carmichaeli-group, with the description of D. wildermuthi sp. nov. from the Central Highlands of Vietnam (Odonata: Zygoptera: Platystictidae).

A modified and expanded definition of the Drepanosticta carmichaeli-group is given. This includes the species: D. annandalei Fraser, 1924, D. brownelli Tinkham, 1938, D. carmichaeli (Laidlaw, 1915), D. emtrai Dow, Kompier Phan, 2018, D. hongkongensis Wilson, 1997, D. jurzitzai Hmlinen, 1999, D. sumatrana Sasamoto Karube, 2007, D. tenella Lieftinck, 1935, D. vietnamica Asahina, 1997 and D. wildermuthi sp. nov.). The species of the group are reviewed and in most cases illustrated, diagnostic notes are given wherever possible. Drepanosticta polychromatica Fraser, 1931 is considered to be a junior synonym of D. carmichaeli and variation in D. carmichaeli is discussed. Drepanosticta wildermuthi sp. nov. from the Central Highlands of Vietnam (holotype male from Bao Loc district, Lam Dong Province) is described. The female of D. jurzitzai Hmlinen, 1999 is described for the first time. A key to the males of the Drepanosticta carmichaeli-group is provided.

Revision of the genus Coeliccia Kirby in Borneo part III: Two new species from the C. membranipes-group from Sarawak and Brunei (Odonata: Zygoptera: Platycnemididae).

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.

A review of Megalogomphus sumatranus (Krüger, 1899) and its allies in Sundaland with a description of a new species from Borneo (Odonata: Anisoptera: Gomphidae).

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.

Two new species of Coeliccia Kirby from Yunnan, China (Odonata: Zygoptera: Platycnemididae).

Two new species of Coeliccia Kirby are described from Yunnan, China: Coeliccia tongbiguan sp. nov. and Coeliccia yunnanensis sp. nov. (holotype ♂ for both from Tongbiguan National Nature Reserve, Yingjiang County, Yunnan). Coeliccia tongbiguan is allied to Coeliccia hoanglienensis Do, known only from Vietnam. Coeliccia yunnanensis appears to be closely allied to the Coeliccia hayashii-group, also from Vietnam. The fifteen named species of Coeliccia now known to occur in China are listed, twelve of them occur in Yunnan, the presence of Coeliccia didyma (Selys) in the country is confirmed.

Protosticta joepani sp. nov. from Borneo with notes on P. kinabaluensis Laidlaw, 1915 (Odonata: Zygoptera: Platystictidae).

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.

Five new species of Coeliccia Kirby, 1890 from Vietnam (Odonata: Platycnemididae), and information on several other species of the genus.

Five new species of Coeliccia (Coeliccia caerulea sp. nov. [holotype: Bao Loc, Lam Dong Prov., appr. 11.449N, 107.712E], Coeliccia coronata sp. nov. [holotype: Bao Loc, Lam Dong Prov., appr. 11.726N, 107.713E], Coeliccia curua sp. nov. [holotype: Ba Be National Park, Bac Kan Prov. appr. 22.413N, 105.610E], Coeliccia diomedea sp. nov. [holotype: Tai Giang, Quang Nam Prov., appr. 16.006N, 107.507E], and Coeliccia pulchella sp. nov. [holotype: Huu Lien Nature Reserve, Lang Son Prov., appr. 21.662N, 106.373E]) are described from Vietnam. The females of C. galbina Wilson Reels, 2003, C. hayashii Phan Kompier, 2016 and C. suoitia Dow, 2016 are described. Coeliccia montana Fraser, 1933 is shown to be a junior synonym of C. pyriformis Laidlaw, 1932.

Amphicnemis rigiketit sp. nov. from Sarawak, with notes on Amphicnemis remiger Laidlaw, 1912 (Odonata: Zygoptera: Coenagrionidae).

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.

A new species of Podolestes Selys, 1862 from peat swamp forest in Sarawak (Odonata: Zygoptera: Argiolestidae).

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].

Drepanosticta adenani sp. nov., from the Lanjak Entimau Wildlife Sanctuary in Sarawak (Odonata: Zygoptera: Platystictidae).

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.

Yunnanosticta gen. nov., from Yunnan, a new genus from the Sinostictinae, with the description of two new species (Odonata: Zygoptera: Platystictidae).

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 emtrai sp. nov. from Vietnam with a discussion of Drepanosticta vietnamica Asahina, 1997 (Odonata: Zygoptera: Platystictidae).

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.

Re-description of Coeliccia erici Laidlaw, and the description of Coeliccia sameerae sp. nov. from Peninsular Malaysia (Odonata: Zygoptera: Platycnemididae).

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.

Revision of the Genus Leptogomphus Selys in Borneo, including gene trees and a two marker molecular phylogeny (Odonata: Anisoptera: Gomphidae).

The Bornean members of the genus Leptogomphus Selys are revised. Two new species are described: Leptogomphus schieli sp. nov. (holotype ♂, Gunung Penrissen, Kuching Division, Sarawak, Malaysia, to be deposited in BMNH) and Leptogomphus sii sp. nov. (holotype ♂, Sungai Sii, upper Baram, Miri Division, Sarawak, Malaysia, in RMNH). Leptogomphus mariae Lieftinck, 1948 is considered to be a junior synonym of L. coomansi Laidlaw, 1936. The true male of L. pasia van Tol, 1990 is described for the first time; male specimens previously treated as L. pasia or L. cf pasia actually belong to a taxon closely allied to, and possibly merely a form of, L. coomansi. A description is given of the female of another new species, but the species is not named in the absence of the male. Female specimens from south-western Sarawak, similar to L. williamsoni Laidlaw, 1912, are considered likely to also represent a distinct species. The female of L. pendleburyi Laidlaw, 1934 is described for the first time and fresh descriptions of the males of L. coomansi, L. pendleburyi and L. williamsoni, and the female of L. coomansi are given. Keys to both sexes, and distribution maps are given. A molecular analysis of the Bornean species (except L. schieli) using the COI and ITS markers is presented.

Drepanosticta rahmani sp. nov., from Kedah, Malaysia (Odonata: Zygoptera: Platystictidae).

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.