ODONATOLOGICA Journal of the Societas Internationalis Odonatologica

Contents Volume 29, Issue 3 2000

Kinvig, R. G.; Samways, M. J. Conserving dragonflies (Odonata) along streams running through commercial forestry pp. 195-208. Commercial afforestation of natural ecosystems is increasing worldwide. There is little information however, on the extent to which biodiversity is being affected by this practice. This is especially so for stream fauna, including the conspicuous Odon. Some dragonflies and damselflies may decline when their natural environment is anthropogenically changed and, as a group, they are sensitive to the impact of afforestation. The sites were four pine plantations in KwaZulu-Natal, South Africa. 14 environmental factors were recorded along stretches of streams running through each of the four sites. The diversity of Odon. spp. and their abundances along these streams were measured. There was a strong positive correlation between certain abiotic factors, for example, boulder cover and shade, with the local distributions of these insects. Water pH was also a strong correlate. Most spp. required both unpolluted water and a sunlit stream. Particular vegetation type and exact distance of pine trees from the water's edge (so long as they did not shade the stream) were not strong correlates. This meant that species diversity dropped dramatically where the water was completely shaded by a closed canopy, whether it was from natural forest or from exotic trees. It is recommended that no plantation trees should shade a stream edge, and should be planted at least 30m from the water. All highly invasive, dense-canopy weeds, especially Acacia mearnsii, should be removed, and extensive and intensive cattle trampling of the banks avoided.

Mahato, M. Resource partitioning among larvae of six coexisting odonate species of the Kali Gandaki River, central Nepal (Anisoptera) pp. 209-223. Odon. larvae were collected from 50-1190 m elevation in central Nepal's Gandaki River from 1984 to 1986. Resource partitioning among coexisting odon. spp. at high (>500m) and low (<500m) elevations was investigated by examining their gut contents. At both elevations, diet differences between Anisogomphus occipitalis and Davidius sp. were statistically significant. A. occipitalis ate mostly midges whereas Davidius sp. ate mayflies and caddisflies as well as midges. At low elevation there was no diet difference between A. occipitalis and Paragomphus lineatus nor between the libellulids Crocothemis servilia and Trithemis festiva. Analyses of niche breadths indicate overlap between Davidius sp., Macromia moorei, C. servilia, and T. festiva, and between A. occipitalis and P. lineatus. Significant diet differences in both A. occipitalis and Davidius sp. between low and high elevations may indicate negative interactions in the presence of other coexisting species at low elevation. Similarly, at low elevation both spp. have a narrow niche breadth, a low average number of prey items per gut, and also more empty guts than at high elevation. Mean body weights of studied odon. were relatively higher at lower elevation than at higher elevation. Predatory interactions seemed to be of little or no importance in structuring this lotic odon. assemblage, in contrast with lentic Odonata in other studies.

Vick, G. S. Mesumbethemis takamandensis gen. nov., spec. nov., a new genus and species of the Tetrathemistinae from Cameroon, with a key to the African genera of the subfamily (Anisoptera: Libellulidae) pp. 225-237. The new sp. is described from a single male from Cameroon (South West Prov., Manyu, Takamanda Forest Reserve, Assam, 06degree01'N, 09degree18'E, alt.140 m, 20-II-1998). The holotype will be deposited in the collection of the Natural History Museum (London). The justification for the placement of the new genus in the Tetrathemistinae is presented. Because of the combination of characters of wing venation which it possesses, the new sp. does not fit into any existing genus and the new genus Mesumbethemis is erected to accommodate it. The unique shape of the anal appendages and the accessory genitalia can at this stage also be regarded as characteristic of this presently-monotypic genus. A key to the African Tetrathemistinae genera is provided.

Carvalho, A. L. Descriptions of the last instar larva and some structures in the pharate male adult of Praeviogomphus proprius Belle, 1995, with notes on the occurrence and taxonomic status of the species (Anisoptera: Gomphidae, Octogomphinae) pp. 239-246. The ultimate instar larva, as well as wing venation and male secondary genitalia of a pharate adult, assigned to P. proprius, are described and figured, based on material from Teresopolis, Rio de Janeiro State, Brazil. Some notes on the collecting site are provided. The taxonomic status of the sp. and the geographic distribution of the Octogomphinae are evaluated.

Costa, J. M.; Santos, T. C. Neocordulia mambucabensis spec. nov., a new dragonfly from Rio de Janeiro Brazil (Anisoptera: Corduliidae) pp. 247-253. The new sp. is described and illustrated and its affinities are discussed. Holotype male, allotype female: Brazil, Rio de Janeiro, Serra da Bocaina, Rio Mambucaba, 22-XI-1979; deposited at MNRJ, Rio de Janeiro. The known spp. of the subgenus Neocordulia are keyed.

Daigle, J. J.; Tennessen, K. J. Heteragrion cooki spec. nov. from Ecuador (Zygoptera: Megapodagrionidae) pp. 255-259. The new sp. is described from Ecuador (holotype male: Pichincha Province, Hotel Tinalandia, 31-I-1997; allotype female: Pichincha prov., Rio Palenque Biological Station, 9-X-1988; both deposited in FSCA). Males can be distinguished by the very large decumbent tooth on the cercus.

Gonzalez-Soriano, E.; del Pilar Villeda-Callejas, M. Ophiogomphus purepecha spec. nov. from Mexico (Anisoptera: Gomphidae) pp. 261-266. The new sp. is described, illustrated and compared with O. arizonicus Kenn. Holotype male: Michoacan state, Los Azufres, Arroyo San Pedro, 4 km NW of San Pedro Jacuaro, alt. 2295 m, 29-XI-1998; allotype female, same data, but 18-XI-1989; deposited at CNIN, UNAM, Mexico. Its discovery in central Mexico represents a notable southern extension of the range of this genus in America.

von Ellenrieder, N.; Muzon, J. Description of the last instar larva of Erythrodiplax nigricans (Rambur) (Anisoptera: Libellulidae) pp. 267-272. The larva is described and illustrated, based on Argentinean specimens. Larval structural features of 14 Erythrodiplax spp. are reviewed.

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