Nesobasis angulicollis Tillyard

Angular-necked Fiji Damselfly (Nesobasis angulicollis)

This species was described in the year 1924.

The Angular-necked Fiji Damselfly species is obviously endemic to the island of Viti Levu, where it can be found at sunny places around medium-sized streams in the highlands, but also at lower elevations.

The sides of the thorax are almost entirely blue colored, males and females are similar in coloration, the females, however, are somewhat paler.

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The name Nesobasis subhumeralis Tillyard is a synonym of this species.

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The genus Nesobasis is endemic to the Fijian Islands, there are at least 11 additional species on the Fijian Islands, that still await their description, among them 10 on the island of Vanua Levu alone.

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References:

[1] T. W. Donnelly: The Fijian genus Nesobasis. Part 1: species of Viti Levu, Ovalau, and Kadavu (Odonata: Coenagrionidae). New Zealand Journal of Zoology 17: 87-117. 1990
[2] H. Van Gossum; C. Beatty; T. Sherratt: The Zygoptera of Viti Levu and Vanua Levu, the two larger islands in the Fiji archipelago. IDF-Report 9: 1-14. 2006
[3] Neal L. Evenhuis; Dan A. Polhemus: Checklist of Odonata of Fiji. Bishop Museum Technical Report 38(15): 1-3. 2007
[4] C. D. Beatty; H. Van Gossum; T. N. Sherratt: Nesobasis species diversity and abundance: Notes on an endemic genus of the island group of Fiji (Zygoptera: Coenagrionidae). Odonatologica 36(1): 13-26. 2007

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Photo: Hans Van Gossum; by courtesy of Hans Van Gossum

Hypothemis hageni Karsch

Hagen’s Skimmer (Hypothemis hageni)

This species was described in 1889, it is endemic to the Fijian Islands, where it is known only from Vanua Levu and Viti Levu.

The females lay their eggs near boulders into floating water with a strong current.

The species appears to be very shy, it perches only for few seconds, and then flies off again.

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The genus Hypothemis is monotypic, that means it contains only a single species.

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hypothemis-hageni-dmm

Photo: Dr. Milen Marinov; by courtesy of Dr. Milen Marinov

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edited: 27.02.2017

Agriocnemis exsudans Sélys

Narrow-winged Damselfly (Agriocnemis exsudans)

The genus Agriocnemis comprises about 40 species, two of which occur within the Polynesian region.

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The Narrow-winged Damselfly shows a wide distribution, which stretches from Australia across Melanesia up to Polynesia, were it is found on the Norfolk Islands, in Fiji, Samoa, and Tonga, and on the Cook Islands. [1][2][3][4]

The species reaches a body length of about 3 cm.

The species mainly inhabits standing waters, but it can also be found at very slow flowing stream sections.

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The name Agriocnemis vitiensis Tillyard is a synonym for this species.

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References:

[1] N. Mary; A. Dutartre; P. Keith; G. Marquet; P. Sasal: Biodiversité des Eaux Douces de Wallis et Futuna; Mission d’Octobre 2004. Rapport Final, Ministère de l’Outre-Mer 2006
[2] C. Morrison; S. Nawadra; M. Tuiwawa: A rapid biodiversity assessment of the Nakorotubu Range, Ra and Tailevu Provinces, Fiji. RAP Bulletin of Biological Assessment 59. Conservation International, Arlington, VA, USA 2009
[3] Milen Marinov: Contribution to the Odonata of the Kingdom of Tonga. Faunistic Studies in South-East Asia and Pacific Island Odonata 1: 1-18. 2013
[4] Milen Marinov; Mark Schmaedick; Dan Polhemus; Rebecca L. Stirnemann; Fialelei Enoka; Pulemagafa Siaifoi Fa’aumu; Moeumu Uili: Faunistic and taxonomic investigations on the Odonata fauna of the Samoan archipelago with particular focus on taxonomic ambiguities in the “Ischnurine complex”. Journal of the International Dragonfly Fund 91: 1-56. 2015

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agriocnemis-exsudans-dmm

Photo: Dr. Milen Marinov; by courtesy of Dr. Milen Marinov

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edited 03.03.2017

Agriocnemis interrupta Fraser

Samoan Narrow-winged Damselfly (Agriocnemis interrupta)

The Samoan Narrow-winged Damselfly was described in the year 1927 on the basis of a single specimen, which was found to be slightly larger than the Narrow-winged Damselfly (Agriocnemis exsudans (Sélys)).

The two do not differ in any other way, and are thus believed to represent a single taxon, which, however, has yet to be validated. [1]

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References:

[1] Milen Marinov; Mark Schmaedick; Dan Polhemus; Rebecca L. Stirnemann; Fialelei Enoka; Pulemagafa Siaifoi Fa’aumu; Moeumu Uili: Faunistic and taxonomic investigations on the Odonata fauna of the Samoan archipelago with particular focus on taxonomic ambiguities in the “Ischnurine complex”. Journal of the International Dragonfly Fund 91: 1-56. 2015

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edited: 14.02.2016

Adversaeschna brevistyla (Rambur)

Blue-spotted Hawker (Adversaeschna brevistyla)

The Blue-spotted Hawker was described in the year 1842, it is the only member of its genus.

The species is widespread across Australia, New Zealand and the Norfolk Islands, here it prefers relatively large lakes and other standing water with tall bankside vegetation, but is often found far from water.

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adversaeschna-brevistyla-nzn

Depiction from: ‘G. V. Hudson: New Zealand Neuroptera: A popular Introduction to the Life Histories and Habits of May Flies, Dragon Flies, Caddis Flies and allied Insects inhabiting New Zealand, including Notes on their relation to Angling. London: West, Newman & Co. 1904′

http://www.biodiversitylibrary.org

Ischnura jeanyvesmeyeri Englund & Polhemus

Raivavae Forktail (Ischnura jeanyvesmeyeri)

This species was described in the year 2010.

The species reaches a body size of about 4,2 cm, the wingspan is about 4,4 cm.

Despite the fact that virtually all streams on the island of Raivavae are diverted for agricultural uses to some extent, the Raivavae Forktail is still quite common at a wide range of elevations, it is, however, restricted to heavily vegetated areas along shaded stream reaches and avoids the adjoining large lowland taro fields, which again are preferred by the widespread Aurora Bluetail (Ischnura aurora Brauer).

The streams on the island of Raivavae are almost always small brooks, less than 1 m wide and only 5 to 15 cm deep, these streams are often lined with thickets of anue (Dicranopteris linearis (Burm. f.) Underw.), with a bed substrate consisting mainly of bare rock, but with abundant root mats and mats of aquatic algae.

The females are known to oviposit in such algae- or root mats.

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References:

[1] R. Englund; D. A. Polhemus: A review of the damselfly fauna of the Austral Islands, French Polynesia, with descriptions of two new species (Odonata: Zygoptera: Coenagrionidae). Tijdschrift voor Entomologie 153(1): 25-40. 2010

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ischnura-jeanyvesmeyeri-rae

Photo: Dr. Ron A. Englund; by courtesy of Dr. Ron A. Englund

Rhyothemis regia (Brauer)

Pacific King Flutterer (Rhyothemis regia)

This beautifully colored dragonfly species is split into at least five subspecies, which are native to the Indo-Australian region.

The Polynesian region itself is inhabited by the subspecies Rhyothemis regia ssp. chalcoptilon Brauer, which is known so far to occur in Fiji, in Samoa, in Tonga, as well as in Wallis and Futuna. [1][2]

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References:

[1] N. Mary; A. Dutartre; P. Keith; G. Marquet; P. Sasal: Biodiversité des Eaux Douces de Wallis et Futuna; Mission d’Octobre 2004. Rapport Final, Ministère de l’Outre-Mer 2006
[2] Milen Marinov; Mark Schmaedick; Dan Polhemus; Rebecca L. Stirnemann; Fialelei Enoka; Pulemagafa Siaifoi Fa’aumu; Moeumu Uili: Faunistic and taxonomic investigations on the Odonata fauna of the Samoan archipelago with particular focus on taxonomic ambiguities in the “Ischnurine complex”. Journal of the International Dragonfly Fund 91: 1-56. 2015

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rhyothemis-r-chalcoptilon-sh

Photo: S. Hashizume, 2008

http://jocv183199.web.fc2.com

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edited: 14.02.2016

Ischnura chromostigma Fraser

Color Spot Forktail (Ischnura chromostigma)

This species was described in the year 1927 on the basis of four males and five females that all had been collected on the island of Tutuila.

The species reaches a wingspan of about 4 cm.

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The Color Spot Forktail may be most closely related to Armstrong’s Slender Damselfly (Amorphostigma armstrongi Fraser), and thus doesn’t belong into the genus Ischnura. [2]

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References:

[1] Milen Marinov; Warren Chin; Eric Edwards; Brian Patrick; Hamish Patrick: A revised and updated Odonata checklist of Samoa (Insecta: Odonata). Faunistic Studies in South-East Asian and Pacific Island Odonata 5: 1-21. 2013
[2] Milen Marinov; Mark Schmaedick; Dan Polhemus; Rebecca L. Stirnemann; Fialelei Enoka; Pulemagafa Siaifoi Fa’aumu; Moeumu Uili: Faunistic and taxonomic investigations on the Odonata fauna of the Samoan archipelago with particular focus on taxonomic ambiguities in the “Ischnurine complex”. Journal of the International Dragonfly Fund 91: 1-56. 2015

Nesobasis brachycerca Tillyard

Short-tailed Fiji Damselfly (Nesobasis brachycerca)

This species was described in the year 1924.

The Short-tailed Fiji Damselfly is restricted to the island of Vanua Levu.

The males and females are mostly identical in coloration, but some females differ in their coloration – it is not known if this represents age-related color changes or color polymorphism, as it can be found in several dragonfly species.

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References:

[1] H. Van Gossum; C. Beatty; T. Sherratt: The Zygoptera of Viti Levu and Vanua Levu, the two larger islands in the Fiji archipelago. IDF-Report 9: 1-14. 2006
[2] Neal L. Evenhuis; Dan A. Polhemus: Checklist of Odonata of Fiji. Bishop Museum Technical Report 38(15): 1-3. 2007
[3] C. D. Beatty; H. Van Gossum; T. N. Sherratt: Nesobasis species diversity and abundance: Notes on an endemic genus of the island group of Fiji (Zygoptera: Coenagrionidae). Odonatologica 36(1): 13-26. 2007
[4] H. Van Gossum; C. D. Beatty; M. Tokota’a; T. N. Sherratt: The Fijian Nesobasis: a further examination of species diversity and abundance (Zygoptera: Coenagrionidae). Odonatologica 37(3): 235-245. 2008

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nesobasis-brachycerca-hvg

Photo: Hans Van Gossum; by courtesy of Hans Van Gossum

Gynacantha stevensoni Fraser

Stevenson’s Duskhawker (Gynacantha stevensoni)

Stevenson’s Duskhawker is known only from the type specimen, a male that was collected in the year 1925 on the island of Tongatapu in Tonga.

The type locality is sometimes erroneously given as Samoa (for example in the IUCN ‘Red List’), but the species probably occurs on the Fijian Islands (The ‘Smithsonian Institution’ lists at least two specimens of this species from Viti Levu / Fiji.).

The biology of this species is unknown so far.

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The insect fauna of the Tongan Islands has been insufficiently studied so far, and the status of many species is completely unknown.

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gynacantha-stevensoni-tnhm

Photo: The Trustees of the Natural History Museum, London

(under creative commons license (4.0))
http://creativecommons.org/licenses/by/4.0

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edited: 23.02.2017