Diversity of the southern Africa Lacustricola Myers, 1924 and redescription of Lacustricola johnstoni (Günther, 1894) and Lacustricola myaposae (Boulenger, 1908) (Cyprinodontiformes, Procatopodidae).

Through the analysis of a comprehensive database of COI sequences, with the sequencing of 48 specimens, a first insight into the genetic diversity, distribution and relationships between the southern Africa "Lacustricola" species is presented. Species from "Lacustricola" occur mainly in freshwater systems within the arid savanna, and are considered to be widely distributed in southern Africa, but most of them are data deficient taxa. Two species are redescribed, "Lacustricola" johnstoni (Günther, 1894) and "Lacustricola" myaposae (Boulenger, 1908), based on specimens collected at their respective type localities. Detailed osteological and life colouration information is presented for the first time. "Lacustricola" johnstoni was described from the Upper Shire River in Mangochi, Lake Malawi but is herein considered as widespread in the Okavango, Zambezi, southern Africa east coastal drainages and the Bangweulu in the Congo System. A sympatric similar species occurring in the Okavango is also identified. "Lacustricola" myaposae (Boulenger, 1908), was described from the Nseleni River in KwaZulu-Natal Province, South Africa and is herein considered to be endemic to the small coastal river drainages within this region. Lectotypes for both "L." johnstoni and "L." myaposae are designated. A new species from the Lualaba River in the Congo System, sister to "L." macrurus is identified, and the deep bodied "L." jubbi is considered sister taxon to a clade including "L." johnstoni and "L." myaposae.

Species succession and the development of a lacustrine fish community in an ephemeral lake.

Here, we present a gillnet survey of Lake Liambezi a 370 km2 shallow ephemeral floodplain lake situated in north-eastern Namibia, which is fed irregularly by the upper Zambezi and Kwando Rivers during years of high flooding. The lake dried up in 1985 and, with the exception of sporadic minor annual inundation events, remained dry until 2007. We describe the temporal succession of fish species over an 8 year period from initial inundation 2007 to maturation in 2014. The succession of the fish community did not follow the typical pattern of opportunistic strategists during colonisation, to periodic strategists that are eventually succeeded by equilibrium strategists. Instead, the evolution of the fish community was characterised by three distinct phases. The first phase involved the inundation and colonisation of the lake in 2007, followed by its decline until the floods that filled the lake in 2009. During this phase the lake was colonised by fishes from the adjacent upper Zambezi and Chobe River floodplains. Fish communities predominantly comprised floodplain specialists including the barbs Enteromius paludinosus and Enteromius poechii, the mormyrid Marcusenius altisambesi and catfishes Schilbe intermedius and Clarias gariepinus. The filling of the lake in the March 2009 floods marked the beginning of the second, successional phase. The barbs declined in abundance and the alestid Rhabdalestes maunensis underwent explosive population growth between 2009 and 2010, but populations crashed equally rapidly and were replaced by Brycinus lateralis which, together with S. intermedius went on to dominate the fish community 2011-2014. Larger, slower growing tilapiine cichlids increased steadily in abundance and became the dominant components in a 2700 t y-1 artisanal fishery that developed on the lake. The fish community in the ephemeral Lake Liambezi is clearly influenced by numerous factors including connectivity, lake level fluctuations, competition and the effects of fishing, which may disrupt typical succession processes in floodplain ecosystems.

A new species of Nemipterus (Pisces: Nemipteridae) from the Western Indian Ocean.

A new species of threadfin bream, Nemipterus flavomandibularis, from the Western Indian Ocean is described and figured. The new species appears most closely related to N. bipunctatus (Valenciennes), but differs principally in colour pattern: N. flavomandibularis is distinct from N. bipunctatus in having two yellow bands on the snout, the upper lip narrowly edged with yellow; and lower lip and chin beneath lip yellow, this colour extending as a narrow band posteriorly to lower margin of opercle. Also, in N. flavomandibularus the scale rows below the lateral line are more or less horizontal (versus distinctly ascending anteriorly in N. bipunctatus), and the maxillary reaches to between level of posterior nostril and anterior margin of eye (versus reaching to below the anterior half of the eye in N. bipunctatus).