Issue 18 (2016)
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IDF Faunistic Studies in Southeast Asian and Pacific Island Odonata Journal of the International Dragonfly Fund 112 Marinov, Milen, Odile FossatiGaschignard & Martin Schorr On a dragonfly collection from Nuku Hiva Island, Marquesas Islands and Paea, Tahiti (French Polynesia) with taxonomic discussion of some Poly nesian genera (Insecta: Odonata) published 28.12.2016 No. 18 ISSN 21954534 The International Dragonfly Fund (IDF) is a scientific society founded in 1996 for the impro vement of odonatological knowledge and the protection of species. Internet: http://www.dragonflyfund.org/ This series intends to contribute to the knowledge of the regional Odonata fauna of the Southeastern Asian and Pacific regions to facilitate costefficient and rapid dissemination of faunistic data. Southeast Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Austra lia. Southeast Asia consists of two geographic regions: Mainland Southeast Asia (Indo china) and Maritime Southeast Asia. Pacific Islands comprise of Micronesian, Melanesian and Polynesian Islands. Editorial Work: Martin Schorr, Milen Marinov and Rory Dow Layout: Martin Schorr IDFhome page: Holger Hunger Printing: Colour Connection GmbH, Frankfurt Impressum: Publisher: International Dragonfly Fund e.V., Schulstr. 7B, 54314 Zerf, Germany. Email: [email protected] Responsible editor: Martin Schorr Cover picture: Pantala flavescens Photographer: Graham Reels Published 28.12.2016 On a dragonfly collection from Nuku Hiva Island, Marquesas Islands and Paea, Tahiti (French Polynesia) with taxonomic discussion of some Polynesian genera (Insecta: Odonata) Milen Marinov1, Odile FossatiGaschignard2 & Martin Schorr3 1Plant Health & Environment Laboratory, Diagnostic and Surveillance Services, Ministry for Primary Industries, 231 Morrin Rd, 1072 Auckland, New Zealand. Email: [email protected] 2Institut de Recherche pour le DéveloppementCentre de Biologie pour la Gestion des Populations, Campus international de Baillarguet, 755 avenue du Campus Agropolis CS 30016, 34988 Montferrier sur Lez Cedex, France. Email: [email protected] 3ÖSTLAP, Schulstrasse 7B, 54314 Zerf, Germany. Email: [email protected] Abstract A small collection of Odonata from Nuku Hiva Island, Marquesas Islands is presented. It adds Anax guttatus as a new species to this oceanic group. Hemicordulia sp. nov. is reported, but not described because the same species has been sampled before and is pending a formal description. A short taxonomic discussion on observed morpho logical similarity of male anal appendages in taxa presently assigned to Amorpho stigma, Hivaagrion and Ischnura east of New Caledonia is provided. Important con siderations for biogeography of the Pacific Odonata are discussed too. Key words: Odonata, dragonflies, damselflies, Marquesas, Pacific Ocean, Coenagrion idae Introduction The Marquesas, an archipelago of French Polynesia comprising a dozen oceanic islands, is one of the most isolated in the world (Galzin et al. 2016). Adamson (1936) ranks it the third isolated island group after Hawaii and Easter Island. The remoteness of the islands have shaped a truly unique flora and fauna much of which is still under investigation and remains undescribed (Gillespie et al. 2008). Lorence et al. (2016) argue that despite their geographic isolation, relatively young geological age (bet ween 1.1 and 5.5 My), small surface area (total of 1,050 km²) and height (highest sum mit at 1,276 m), the native (primary) vascular flora of the Marquesas is composed of approximately 332 taxa (313 species, 4 subspecies and 15 varieties), with 48% en demism. Marquesas shelter the most diverse assemblages of marine birds of the tropical South Pacific with 21 breeding species (Thibault et al. 2016). Terrestrial arthro Faunistic Studies in SE Asian and Pacific Island Odonata 18 | 1 Marinov, FossatiGaschignard & Schorr pods are characterised with both diversity and endemism with perhaps as many as 1,500 species in total (Roderick & Gillespie 2016). The young oligotrophic rivers harbour 17 freshwater fishes (nine endemic) and nine decapod crustaceans (one endemic) and are unique in having no introduced species (Keith & Sasal 2016). The herpetofauna is without endemism, but a finer scale analysis clearly shows genetic isolation of its populations and is also noteworthy by the higher density of several spe cies which are rare at other places (Ineich 2016). Aquatic macroinvertebrates on the Marquesas Islands are of particular interest for the absence of species from otherwise widely distributed orders such as Plecoptera, Ephemeroptera and Mecoptera (Adamson 1939). Aquatic Coleoptera are also not known while Trichoptera are represented with one still unidentified genus and species (Polhemus & Englund 2016). Remarkably the total aquatic communities of insects are represented mainly by members of two orders Odonata and Diptera with some Heteroptera living in the littoral zones of streams and rivers. Generally Odonata species of the Marquesas Islands (as well as the whole of French Polynesia) have been understudied (Polhemus & Englund 2016). Until recently, infor mation on arthropods (including Odonata) was largely confined to a series of articles published by the Bishop Museum (Honolulu), as a result of the Pacific Entomolo gical Survey in the 1920s and 1930s (Gillespie et al. 2008). A more recent report on the freshwater entomological diversity on the Marquesas and Tahiti was published in Polhemus et al. (2000b). That report brings up very important discussion points on the taxonomy of Hemicordulia Needham, 1901 and the local endemic Hivaagrion Hä mäläinen & Marinov, 2014. The latter is included in the report as Bedfordia Mumford, 1942, however Hämäläinen & Marinov (2014) demonstrated that this genus name has already been preoccupied by the name Bedfordia Fahrenholz, 1936 in Phthira ptera and suggested the replacement name Hivaagrion. Genus Hivaagrion is under going a taxonomic revision (Polhemus et al. 2000b) because it is supposed to be re presented by endemic species especially at the higher altitudes with at least six new species strictly endemic to the islands of Eiao, Nuku Hiva, Hiva Oa and Ua Huka (Pol hemus & Englund 2016). Therefore a detailed historic literature account of the Odonata fauna of the Marquesas, although of particular interest as it has never been done before, is beyond the scope of the current research. It will be postponed until after the completion of the revision of Hivaagrion. Here we report on a small collection of Odonata from Nuku Hiva Island only. Faunistic data are analysed in conjunction with taxonomic information from other islands within French Polynesia and compared to endemic species on the neighbouring Samoan archipelago. Material and Methods According to Gazlin et al. (2016), the Marquesas Islands are located between 7°5' and 10°35' South latitude and 138° 30' and 140° 45' West longitude (Fig. 1). This Pacific group is the northernmost of the five archipelagos that make up French Polynesia and closest to the equator. Situated about 5,000 km from the continents, 4,000 km from the Hawaiian Islands and 1,400 km from Tahiti (Society Islands), the Marquesas 2 | Faunistic Studies in SE Asian and Pacific Island Odonata 18 Odonata from Marquesas and Tahiti islands Figure 1. Geographic position of the island of Nuku Hiva and other Marquesas Is lands. Inlet – Nuku Hiva and other major islands within the Marquesas. archipelago is considered as one of the most distant from all continents and there fore the most isolated in the world. Three geographic and geological groups can be distinguished: northern group (Eiao, Hatu Tu or Hatu Taa, the sandy islet of Motu One and the benches Jean Goguet and Clark which are shoals located respectively 30 and 10 m deep), one Central group (Nuku Hiva, Ua Pou, Ua Huka, Motu Iti or Haut Iti) situated about 90 km from the northern group, and a southern group (Fatu Uku, Hiva Oa, Moho Tani, Fatu Iva Islet of Motu Nao, the Thomasset rochet, the Dumont Durville highland) located about 110 km from the central group. The largest islands in the archipelago, which are Nuku Hiva with 340 km2, and Hiva Oa with 315 km2, each represent only one third of the surface of Tahiti (1045 km2). The smaller ones include Motu One (0.5 km2), Motu Iti (0.8 km2), Fatu Uku (7.5 km2), Hatu Tu (7.5 km2) and Moho Tani (9 km2). Laurent (2016) identifies the climate on the Marquesas as lowmoist tropical, an almost extratropical climate. Influenced by east trade winds and hot ocean waters, the average annual air temperature does not change much during the year and is usually between 25°C and 27°C. The rainfalls is mainly orographic. Annual precipi tation varies from 927 mm in Hakahau located in the north of the archipelago to 2,227 mm in Vaitahu at the southern end. The atmospheric and oceanic conditions of the Marquesas Island do not generate are adverse at the processes of deep convection, hence the region exhibits scarce cyclonic activity. However, exceptionally, cycloge nesis conditions can be observed, for example in 19821983, generating an intense tropical cyclone. Finally, the Marquesan seasonal cycle looks to be influenced by the Faunistic Studies in SE Asian and Pacific Island Odonata 18 | 3 Marinov, FossatiGaschignard & Schorr various phases of ENSO (El Niño Southern Oscillation) and IPO (Interdecadal Pacific Oscillation). Keith & Sasal (2016) classify the rivers of the Marquesas into five zones according to the altitude and the speed of the current: zone of the sources from 700 m, superior course between 300 and 700 m, average course between 100 and 300 m, lower part of the rivers between 20 and 100 m, lower course below 20 m. Their hydrology regime de pends largely on rainfalls and varies between years (Fossati et al. 1994). The material for this publication was sampled during the work on a programme to control the biting insect Simulium buissoni Roubaud, 1906 the results of which were reported in Fossati et al.