Three new species of the genus Ceylonosticta Fraser, 1931 (Odonata: Zygoptera: Platystictidae) from Sri Lanka and the rediscovery of Ceylonosticta subtropica (Fraser, 1933)

Three new species of Ceylonosticta are described and illustrated: Ceylonosticta nancyae sp. nov., Ceylonosticta rupasinghe sp. nov. and Ceylonosticta alwisi sp. nov. from Samanala Nature Reserve (Adam’s Peak), Kuruwita-Erathna footpath, Ratnapura District, Sri Lanka. Ceylonosticta subtropica has been recorded for the first time after 83 years and the first depiction of its genital ligula is…

Dragonflies (Insecta: Odonata) as indicators of habitat quality in Mediterranean streams and rivers in the province of Barcelona (Catalonia, Iberian Peninsula)

In a field study carried out in 2011 and 2014 adult dragonflies were identified as a rapid and easy-to-use means of assessing habitat quality and biological integrity of Mediterranean streams and rivers in the province of Barcelona (Region Catalonia, Iberian Peninsula). The study included sampling sites from five different river catchments: Besòs, Foix, Llobregat, Ter…

Redescription of the holotype of Mecistogaster pronoti Sjöstedt, 1918 (Zygoptera: Pseudostigmatidae)

Mecistogaster pronoti Sjöstedt, 1918 was described based on a female holotype deposited in the Naturhistoriska Riksmuseet, Stockholm, collected in the state of Espírito Santo, Brazil. The original description has no illustrations, which makes its identification very difficult. Herewith we redescribe and illustrate this holotype. The species is red listed and considerations regarding its conservation are…

A hotspot for threatened Mediterranean odonates in the Seybouse River (Northeast Algeria): are IUCN population sizes drastically underestimated?

Several odonate species are threatened in the Mediterranean basin and some of them show alarming decreasing trends. The distribution and population estimations provided by the IUCN are based on occasional field sampling or non-rigorous methodologies and could be erroneous and misleading. To obtain reliable estimations of the population size and distribution of three threatened species,…

Detection probabilities and sampling rates for Anisoptera exuviae along river banks: influences of bank vegetation type, prior precipitation, and exuviae size

Exuviae collections have considerable value in population studies of Odonata, but methods for standardizing collections or estimating densities and detection probabilities have been little studied. I measured sampling rates for Anisoptera exuviae and used a maximum likelihood, four-pass, depletion population estimator to standardize collections and to estimate exuvial densities and detection probabilities along 10 riverbank…

Local extinctions and range contraction of the endangered Coenagrion mercuriale in North Africa

Freshwater biodiversity is currently threatened worldwide. In North Africa, 24.4% of Odonata are regionally threatened with extinction. In this region, freshwater resources are particularly scarce and an increasing shortage of water is expected. To better understand the current threats to the endangered North African damselfly Coenagrion mercuriale we updated information on extinct and extant populations…

An update on the distribution of threatened odonate species from the Greater Antilles

The Antilles harbour several island endemic odonate species, including some palaeoendemics, within a relatively small and anthropized area. Such attributes give this archipelago a special significance for the conservation of Odonata in the Neotropics. However, despite the importance of these islands, inadequately surveyed regions persist, mainly in the Greater Antilles, and there is not enough…

Does the damming of streams in the southern Amazon basin affect dragonfly and damselfly assemblages (Odonata: Insecta)? A preliminary study

Our goal was to investigate whether the loss of riparian forests alters the structure of assemblages and populations of dragonflies and damselflies. We tested the hypothesis that the composition of the odonate assemblages found upstream from dams are significantly different from those found downstream of these barriers. To test the hypothesis, we investigated stream sectors…