Thlapi: Fish Systematics and Taxonomy

24/07/2026

The day we have all been waiting for🥳🥳🥳💃🏾 SAIAB OPEN DAY!!! Get a chance to meet the winnings team at solve ALL TAXONOMIC MYSTERIES!!🧬🐟

23/07/2026

Meet Dr Martinus Scheepers, his research aims are to understand African fish diversity, biogeography, and drivers of speciation, particularly in the family Cyprinidae, an infamously problematic group in terms of systematics🤔. He uses a combination of morphological, molecular, and geographic data to revise the taxonomy, and to understand the evolution of cyprinids in Africa. In addition, he is also involved with developing protocols for the use of both environmental DNA (eDNA), and DNA 🧬 from formalin-fixed specimens for freshwater fish biodiversity monitoring in South Africa. Check out Tinus and the rest of the team on the SAIAB website: https://saiab.ac.za/platforms/fresh-water-field-unit/

23/07/2026

Meet Dr Tholoana Ntokoane, A post-doctoral research fellow at SAIAB, her research focus is on using integrative taxonomy, combining morphological and genetic evidence🧬, to study and understand the diversity of freshwater fishes. Her other research interests is in museomics where she is working on ways she can extract DNA from museum specimens to explore the genetic diversity and unlock 🔓 the hidden value of museum collections. Check out Dr Tholoana on https://saiab.ac.za/platforms/fresh-water-field-unit/

23/07/2026

Meet Dr Tadiwa Mutizwa.
An aquatic biologist with with a passion for biodivesity conservation. His research involves taxonomy and systematics of African freshwater fishes as well as the integration of molecular approaches such as eDNA 🧬 and museomics to investigate the genetic diversity in our ever changing aquatic systems.
For more information on Dr Tadiwa Mutizwa checkout https://saiab.ac.za/platforms/fresh-water-field-unit/

20/07/2026

20/07/2026

Today, ahead of Endangered Species Day, we shine a spotlight on a world of incredible aquatic species - many now facing the threat of extinction. 🌊

The Agulhas redfin (Pseudobarbus agulhas) was only officially described in 2025, but this small freshwater fish has been evolving in the rivers at Africa’s southernmost tip for millions of years.
Today, however, the species is facing an uncertain future.
Surveys across the Heuningnes catchment by the Nuwejaars River Nature Reserve (NRNR), the non-profit company responsible for protecting the Nuwejaars Wetlands Special Management Area, have revealed just how precarious its situation has become.

In a river system stretching over 670 km, Agulhas redfin have been found in only 11 km of river, with fewer than 250 individuals recorded during monitoring.
To help prevent this species from slipping into extinction, NRF-SAIAB is collaborating with the NRNR and other partners to conserve the Agulhas redfin and other threatened fynbos fish, such as the Heuningnes galaxias (Galaxias sp. nov. ‘Heuningnes').

As an urgent first step, redfin from four remaining subpopulations have already been translocated to two secure off-stream dams, where they are being safeguarded and given an opportunity to breed. The next critical step is the establishment of a dedicated sanctuary - a protected site where these fish can be released into habitat free from one of their greatest threats: invasive alien fish.
Creating this sanctuary will require specialist planning, infrastructure and significant resources. It is an essential step if we are to secure the future of one of South Africa’s newest and most threatened freshwater fish species.

20/07/2026

On this Endangered Species Day, we stand in support of the species facing growing threats beneath the surface of our rivers, estuaries, and oceans. 💧

Nameless and vulnerable: the case of the Verlorenvlei galaxias

Africa has a group of iconic freshwater fishes that are only found at the southern tip of the continent. The closest relatives of these fishes are found in Australia, New Zealand and South America. For a long time, scientists had only recognised a single galaxxid species on the African continent. However, advances in recent years, particularly through the use of molecular data has indicated that the Cape galaxias (Galaxias zebratus) contains multiple elements/lineages (or species) “hidden” within it.

One of these lineages is the Verlorenvlei galaxias, which scientists have tentatively nicknamed Galaxias sp. nov. 'Verlorenvlei', to indicate that it has no formal scientific name. This small, slender freshwater fish is confined to the Verlorenvlei River system in the Western Cape, where it is currently known from only two isolated localities. It has only been recorded from the upper Kruismans River and the lower reaches of the Verlorenvlei River before it discharges into the Verlorenvlei Wetland.

A comprehensive field survey undertaken in 2015 confirmed the lineage’s restricted distribution and highlighted that it faced immense pressure from invasive alien fish and excessive or complete water abstraction. The surveys also documented that these two subpopulations are represented by small population sizes. Existence in a fragmented habitat, small population sizes and the threats to the continued persistence of this lineage led to its classification as Endangered in the IUCN Red List of Threatened species (Chakona et al., 2016; 2022).

Nearly a decade has passed, and because this species has not yet been formally described, no dedicated conservation efforts have been implemented. Although there are planned interventions for the co-distributed Verlorenvlei redfin (Pseudobarbus verloreni), the Verlorenvlei galaxias occurs in sections where the redfin does not occur, highlighting the need for conservation measures specifically tailored to this species.

To help fill this gap, the fish systematics and taxonomy team (THLAPI) at the NRF-South African Institute for Aquatic Biodiversity is currently in the process of formally describing the Verlorenvlei galaxias as a new species. This formal recognition is an important step to amplify the need for it to be considered in the conservation planning initiatives in the province. It provides the taxonomic foundation needed to integrate the species into biodiversity legislation and long-term management planning, giving this overlooked fish the conservation support it needs to survive.

Photo Credit: Prof Albert Chakona & Xiluva Mathebula, NRF-SAIAB