Morphological diversity of the genus Telmatochromis from the Lake Tanganyika drainage with the description of a new riverine species and the generic reassignment of the Malagarasi River lamprologine.

The lamprologine cichlid genus Telmatochromis was long considered primarily lacustrine and endemic to Lake Tanganyika until an undescribed Telmatochromis species was reported from the Lufubu River (Lake Tanganyika drainage, Zambia). A phylogenomic study in 2021 confirmed the association of Telmatochromis sp. "lufubu" with Telmatochromis along with another riverine species, Neolamprologus devosi (Malagarasi drainage, Tanzania).

Diet and habitat as determinants of intestine length in fishes.

Unlabelled: Fish biologists have long assumed a link between intestinal length and diet, and relative gut length or Zihler's index are often used to classify species into trophic groups. This has been done for specific fish taxa or specific ecosystems, but not for a global fish dataset. Here, we assess these relationships across a dataset of 468 fish species (254 marine, 191 freshwater, and 23 that occupy both habitats) in relation to body mass and fish length.

The genetics of niche-specific behavioral tendencies in an adaptive radiation of cichlid fishes.

Behavior is critical for animal survival and reproduction, and possibly for diversification and evolutionary radiation. However, the genetics behind adaptive variation in behavior are poorly understood. In this work, we examined a fundamental and widespread behavioral trait, exploratory behavior, in one of the largest adaptive radiations on Earth, the cichlid fishes of Lake Tanganyika.

Revision of the cichlid fish genus Gnathochromis (Teleostei: Cichlidae) from Lake Tanganyika with the description of a new genus Jabarichromis gen. nov.

The cichlid species flock from Lake Tanganyika is a well-studied system for evolutionary biology research because its species assemblage shows a high degree of endemism and is a product of adaptive radiation. While our understanding of the evolutionary history of Lake Tanganyika cichlids has advanced tremendously over the past decades, their taxonomy received considerably less attention, despite numerous taxonomic misplacements (e.g.

Host adaptive radiation is associated with rapid virus diversification and cross-species transmission in African cichlid fishes.

Adaptive radiations are generated through a complex interplay of biotic and abiotic factors. Although adaptive radiations have been widely studied in the context of animal and plant evolution, little is known about how they impact the evolution of the viruses that infect these hosts, which in turn may provide insights into the drivers of cross-species transmission and hence disease emergence. We examined how the rapid adaptive radiation of the cichlid fishes of African Lake Tanganyika over the last 10 million years has shaped the diversity and evolution of the viruses they carry.

Visual opsin gene expression evolution in the adaptive radiation of cichlid fishes of Lake Tanganyika.

Tuning the visual sensory system to the ambient light is essential for survival in many animal species. This is often achieved through duplication, functional diversification, and/or differential expression of visual opsin genes. Here, we examined 753 new retinal transcriptomes from 112 species of cichlid fishes from Lake Tanganyika to unravel adaptive changes in gene expression at the macro-evolutionary and ecosystem level of one of the largest vertebrate adaptive radiations.

The ectodysplasin-A receptor is a candidate gene for lateral plate number variation in stickleback fish.

Variation in lateral plating in stickleback fish represents a classical example of rapid and parallel adaptation in morphology. The underlying genetic architecture involves polymorphism at the ectodysplasin-A gene (EDA). However, lateral plate number is influenced by additional loci that remain poorly characterized.

Molecular evolution and depth-related adaptations of rhodopsin in the adaptive radiation of cichlid fishes in Lake Tanganyika.

The visual sensory system is essential for animals to perceive their environment and is thus under strong selection. In aquatic environments, light intensity and spectrum differ primarily along a depth gradient. Rhodopsin (RH1) is the only opsin responsible for dim-light vision in vertebrates and has been shown to evolve in response to the respective light conditions, including along a water depth gradient in fishes.

Tracing evolutionary decoupling of oral and pharyngeal jaws in cichlid fishes.

Evolutionary innovations can facilitate diversification if the novel trait enables a lineage to exploit new niches or by expanding character space. The elaborate pharyngeal jaw apparatus of cichlid fishes is often referred to as an evolutionary "key innovation" that has promoted the spectacular adaptive radiations in these fishes. This goes back to the idea that the structural and functional independence of the oral and pharyngeal jaws for food capturing and food processing, respectively, permitted each jaw type to follow independent evolutionary trajectories.

Dynamics of sex chromosome evolution in a rapid radiation of cichlid fishes.

Sex is a fundamental trait determined by environmental and/or genetic factors, including sex chromosomes. Sex chromosomes are studied in species scattered across the tree of life, yet little is known about tempo and mode of sex chromosome evolution among closely related species. Here, we examine sex chromosome evolution in the adaptive radiation of cichlid fishes in Lake Tanganyika.

The non-gradual nature of adaptive radiation.

Adaptive radiation is a major source of biodiversity. Still, many aspects of this evolutionary process remain poorly understood. Our recent integrative examination of the cichlid adaptive radiation in African Lake Tanganyika provides new insights into the process of explosive diversification.

evALLution: making basic evolution concepts accessible to people with visual impairment through a multisensory tree of life.

Background: People with visual impairment have benefitted from recent developments of assistive technology that aim to decrease socio-economic inequality. However, access to post-secondary education is still extremelly challenging, especially for scientific areas. The under representation of people with visual impairment in the evolution research community is connected with the vision-based communication of evolutionary biology knowledge and the accompanying lack of multisensory alternatives for learning.

Gene expression dynamics during rapid organismal diversification in African cichlid fishes.

Changes in gene expression play a fundamental role in phenotypic evolution. Transcriptome evolutionary dynamics have so far mainly been compared among distantly related species and remain largely unexplored during rapid organismal diversification, in which gene regulatory changes have been suggested as particularly effective drivers of phenotypic divergence. Here we studied gene expression evolution in a model system of adaptive radiation, the cichlid fishes of African Lake Tanganyika.

Drivers and dynamics of a massive adaptive radiation in cichlid fishes.

Adaptive radiation is the likely source of much of the ecological and morphological diversity of life. How adaptive radiations proceed and what determines their extent remains unclear in most cases. Here we report the in-depth examination of the spectacular adaptive radiation of cichlid fishes in Lake Tanganyika.

The genomic timeline of cichlid fish diversification across continents.

Cichlid fishes are celebrated for their vast taxonomic, phenotypic, and ecological diversity; however, a central aspect of their evolution - the timeline of their diversification - remains contentious. Here, we generate draft genome assemblies of 14 species representing the global cichlid diversity and integrate these into a new phylogenomic hypothesis of cichlid and teleost evolution that we time-calibrate with 58 re-evaluated fossil constraints and a new Bayesian model accounting for fossil-assignment uncertainty. Our results support cichlid diversification long after the breakup of the supercontinent Gondwana and lay the foundation for precise temporal reconstructions of the exceptional continental cichlid adaptive radiations.

The taxonomic diversity of the cichlid fish fauna of ancient Lake Tanganyika, East Africa.

Ancient Lake Tanganyika in East Africa houses the world's ecologically and morphologically most diverse assemblage of cichlid fishes, and the third most species-rich after lakes Malawi and Victoria. Despite long-lasting scientific interest in the cichlid species flocks of the East African Great Lakes, for example in the context of adaptive radiation and explosive diversification, their taxonomy and systematics are only partially explored; and many cichlid species still await their formal description. Here, we provide a current inventory of the cichlid fish fauna of Lake Tanganyika, providing a complete list of all valid 208 Tanganyikan cichlid species, and discuss the taxonomic status of more than 50 undescribed taxa on the basis of the available literature as well as our own observations and collections around the lake.

Structural manipulations of a shelter resource reveal underlying preference functions in a shell-dwelling cichlid fish.

Many animals can modify the environments in which they live, thereby changing the selection pressures they experience. A common example of such niche construction is the use, creation or modification of environmental resources for use as nests or shelters. Because these resources often have correlated structural elements, it can be difficult to disentangle the relative contribution of these elements to resource choice, and the preference functions underlying niche-construction behaviour remain hidden.

Genomic release-recapture experiment in the wild reveals within-generation polygenic selection in stickleback fish.

How rapidly natural selection sorts genome-wide standing genetic variation during adaptation remains largely unstudied experimentally. Here, we present a genomic release-recapture experiment using paired threespine stickleback fish populations adapted to selectively different lake and stream habitats. First, we use pooled whole-genome sequence data from the original populations to identify hundreds of candidate genome regions likely under divergent selection between these habitats.

A functional trade-off between trophic adaptation and parental care predicts sexual dimorphism in cichlid fish.

Although sexual dimorphism is widespread in nature, its evolutionary causes often remain elusive. Here we report a case where a sex-specific conflicting functional demand related to parental care, but not to sexual selection, explains sexual dimorphism in a primarily trophic structure, the gill rakers of cichlid fishes. More specifically, we examined gill raker length in a representative set of cichlid fish species from Lake Tanganyika featuring three different parental care strategies: (i) uni-parental mouthbrooding, whereby only one parental sex incubates the eggs in the buccal cavity; (ii) bi-parental mouthbrooding, whereby both parents participate in mouthbrooding; and (iii) nest guarding without any mouthbrooding involved.

Point-Combination Transect (PCT): Incorporation of small underwater cameras to study fish communities.

Available underwater visual census (UVC) methods such as line transects or point count observations are widely used to obtain community data of underwater species assemblages, despite their known pit-falls. As interest in the community structure of aquatic life is growing, there is need for more standardized and replicable methods for acquiring underwater census data.Here, we propose a novel approach, Point-Combination Transect (PCT), which makes use of automated image recording by small digital cameras to eliminate observer and identification biases associated with available UVC methods.

Variation of anal fin egg-spots along an environmental gradient in a haplochromine cichlid fish.

Male secondary sexual traits are targets of inter- and/or intrasexual selection, but can vary due to a correlation with life-history traits or as by-product of adaptation to distinct environments. Trade-offs contributing to this variation may comprise conspicuousness toward conspecifics versus inconspicuousness toward predators, or between allocating resources into coloration versus the immune system. Here, we examine variation in expression of a carotenoid-based visual signal, anal-fin egg-spots, along a replicate environmental gradient in the haplochromine cichlid fish Astatotilapia burtoni.

Speciation: Genomic Archipelagos in a Crater Lake.

The opening stages of speciation remain poorly understood, especially from a genomic perspective. The genomes of newly discovered crater-lake cichlid fish shed light on the early phases of diversification and suggest that selection acts on multiple genomic regions.

Adaptive divergence between lake and stream populations of an East African cichlid fish.

Divergent natural selection acting in different habitats may build up barriers to gene flow and initiate speciation. This speciation continuum can range from weak or no divergence to strong genetic differentiation between populations. Here, we focus on the early phases of adaptive divergence in the East African cichlid fish Astatotilapia burtoni, which occurs in both Lake Tanganyika (LT) and inflowing rivers.