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

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

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

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

Ischnura aurora Brauer

Aurora Bluetail (Ischnura aurora)

The genus Ischnura is distributed nearly worldwide, within the Polynesian region it contains 13 described species, plus at least an additional ten hitherto undescribed species, which are known to await their description alone on the Society Islands.

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The Aurora Bluetail is a wandering species, which occurs from India well into East Polynesia.

It is a smaller damselfly species, which reaches a wingspan of about 3 cm. The males are very colorful (see photograph), while the females are rather plain light brown in color.

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The enigmatic Spinytail Forktail (Ischnura spinicauda (Brauer)), described in the year 1865 as a distinct species, is now known to be identical with the Aurora Bluetail. [7]

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References:

[1] M. A. Lieftinck: Some Odonata of Rapa Island, with descriptions of three Polynesian species of Ischnura Charpentier. Tijdschrift voor Entomologie 109: 89-102. 1966
[2] Karin S. Kami; Scott E. Miller: Samoan Insects and related Arthropods: Checklist and Bibliography. Bishop Museum Technical Report 13. 1998
[3] 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
[4] 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
[5] R. J. Rowe: Ischnura aurora (Brauer 1865) (Zygoptera: Coenagrionidae), an Australo-Pacific species. New Zealand Journal of Zoology 37(2): 189-192. 2010
[6] S. A. Hathaway; K. McEachern; R. N. Fisher: Terrestrial Forest Management Plan for Palmyra Atoll: U.S. Geological Survey Open-File Report 2011-1007, 78 p. 2011
[7] 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
[8] Milen Marinov; Odile Fossati-Gaschignard; Martin Schorr: On a dragonfly collection from Nuku Hiva, Marquesas Islands and Paea, Tahiti (French Polynesia) with taxonomic discussion of some Polynesian genera (Insecta: Odonata). Faunistic Studies in South-east Asian and Pacific Island Odonata 18: 1-12. 2016

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ischnura-aurora-df

Photo: Dennis Farrell; by courtesy of Dennis Farrell

http://thaiodonata.blogspot.com

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edited: 18.01.2017

Melanesobasis mcleani Donnelly

McLean’s Slender Damselfly (Melanesobasis mcleani)

This exceedingly beautiful species was described in the year 1984.

McLean’s Slender Damselfly is endemic to the island of Viti Levu, where it is found in shady parts of small streams.

The Thorax is dark bluish violet in colour, the very long and slender abdomen is very dark blackish blue coloured, the head is dark blackish blue, with the big round eyes being of a sky blue colour. The legs are flesh-coloured.

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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] C. Morrison; S. Nawadra; M. Tuiwawa (ed.): Arapid biodiversity assessment of the Nakorotabu Range, Ra and Tailevu Provinces, Fiji. RAP Bulletin of Biological Assessment 59. Conservation International, Arlington, VA, USA. 2009

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melanesobasis-mcleani-dmm

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