Evolution in the Fast Lane: Diversity, Ecology, and Speciation of Cichlids in the Lower Congo River

Alter, S. Elizabeth

doi:10.1007/978-94-024-2080-7_4

Cited by 6 publications

(12 citation statements)

References 55 publications

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“…This pattern of high admixture may result from the more gentle elevational incline in this region compared with the larger elevational drops below Mbelo and around Inga (Figure 1). While small‐bodied, physoclistous cichlid species have limited intrinsic dispersal capabilities in deep and/or fast‐flowing waters (Stiassny & Alter, 2021), dispersal may be facilitated for such a small‐bodied, eurytopic species as L . tigripictilis during wet seasons when river banks are flooded, particularly in regions of gentle elevational incline.…”

Section: Discussionmentioning

confidence: 99%

“…lethops live at extreme depths in LCR canyons in low‐light environments (Aardema et al, 2020; Stiassny & Alter, 2021). Lower Congo Lamprologus are small‐bodied, physoclistous cichlids with limited intrinsic dispersal capabilities, particularly in deep and/or fast‐flowing waters (Stiassny & Alter, 2021). Although it is currently unknown in L .…”

Section: Introductionmentioning

confidence: 99%

“…While the precise habitat of L . lethops remains conjectural (Stiassny & Alter, 2021), L . werneri and L .…”

Section: Introductionmentioning

confidence: 99%

“…Lamprologus lethops is the only cichlid species to exhibit striking degenerative features, including an overall degeneration of the eyes and loss of pigmentation (Roberts & Stewart, 1976;Schobert et al, 2013). Available evidence suggests that L. lethops live at extreme depths in LCR canyons in low-light environments (Aardema et al, 2020;Stiassny & Alter, 2021). Lower Congo Lamprologus are small-bodied, physoclistous cichlids with limited intrinsic dispersal capabilities, particularly in deep and/or fast-flowing waters (Stiassny & Alter, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Available evidence suggests that L. lethops live at extreme depths in LCR canyons in low-light environments (Aardema et al, 2020;Stiassny & Alter, 2021). Lower Congo Lamprologus are small-bodied, physoclistous cichlids with limited intrinsic dispersal capabilities, particularly in deep and/or fast-flowing waters (Stiassny & Alter, 2021). Although it is currently unknown in L. lethops, other Lamprologus are pair-bonding substrate spawners, and breeding males establish and defend small territories in and around rocks where eggs are laid in caves and crevices rather than on open substrate.…”

Section: Introductionmentioning

confidence: 99%

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Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

et al. 2022

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Freshwater fishes are notably diverse, given that freshwater habitat represents a tiny fraction of the earth's surface, but the mechanisms generating this diversity remain poorly understood. Rivers provide excellent models to understand how freshwater diversity is generated and maintained across heterogeneous habitats. In particular, the lower Congo River (LCR) consists of a dynamic hydroscape exhibiting extraordinary aquatic biodiversity, endemicity, morphological and ecological specialization. Previous studies have suggested that the numerous high‐energy rapids throughout the LCR form physical barriers to gene flow, thus facilitating diversification and speciation, generating ichthyofaunal diversity. However, this hypothesis has not been fully explored using genome‐wide SNPs for fish species distributed across the LCR. Here, we examined four lamprologine cichlids endemic to the LCR that are distributed along the river without range overlap. Using genome‐wide SNP data, we tested the hypotheses that high‐energy rapids serve as physical barriers to gene flow that generate genetic divergence at interspecific and intraspecific levels, and that gene flow occurs primarily in a downstream direction. Our results are consistent with the prediction that powerful rapids sometimes act as a barrier to gene flow but also suggest that, at certain temporal and spatial scales, they may provide multidirectional dispersal opportunities for riverine rheophilic cichlid fishes. These results highlight the complexity of diversification processes in rivers and the importance of assessing such processes across different riverscapes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…While the precise habitat of L . lethops remains conjectural (Stiassny & Alter, 2021), L . werneri and L .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

et al. 2022

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The Mechanosensory Lateral Line System of Cichlid Fishes: From Anatomy to Behavior

Webb

Maruska

Butler

et al. 2021

The Behavior, Ecology and Evolution of Cichlid Fishes

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Impacts of Quaternary Climatic Changes on the Diversification of Riverine Cichlids in the Lower Congo River

Kurata,

Stiassny,

Hickerson

et al. 2024

Integrative and Comparative Biology

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Climatic and geomorphological changes during the Quaternary period impacted global patterns of speciation and diversification across a wide range of taxa, but few studies have examined these effects on African riverine fishes. The lower Congo River is an excellent natural laboratory for understanding complex speciation and population diversification processes as it is hydrologically extremely dynamic and recognized as a continental hotspot of diversity harboring many narrowly endemic species. A previous study using genome-wide SNP data highlighted the importance of dynamic hydrological regimes to the diversification and speciation in lower Congo River cichlids. However, historical climate and hydrological changes (e.g., reduced river discharge during extended dry periods) have likely also influenced ichthyofaunal diversification processes in this system. The lower Congo River offers a unique opportunity to study climate-driven changes in river discharge, given the massive volume of water from the entire Congo basin flowing through this short stretch of the river. Here, we, for the first time, investigate the impacts of paleoclimatic factors on ichthyofaunal diversification in this system by inferring divergence times and modeling patterns of gene flow in four endemic lamprologine cichlids, including the blind cichlid, Lamprologus lethops. Our results suggest that Quaternary climate changes associated with river discharge fluctuations may have impacted the diversification of species along the system. Our study, using reduced representation sequencing (2RADseq), indicates that the lower Congo River lamprologines emerged during the Early-Middle Pleistocene transition, characterized as one of the earth's major climatic transformation periods. Modeling results suggest that gene flow across populations and between species was not constant but occurred in temporally constrained pulses. We show that these results correlate with glacial-interglacial fluctuations. The current hyper-diverse fish assemblages of the lower Congo River riverscape likely reflect the synergistic effects of multiple drivers fueling complex evolutionary processes through time.

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Evolution in the Fast Lane: Diversity, Ecology, and Speciation of Cichlids in the Lower Congo River

Cited by 6 publications

References 55 publications

Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

The Mechanosensory Lateral Line System of Cichlid Fishes: From Anatomy to Behavior

Impacts of Quaternary Climatic Changes on the Diversification of Riverine Cichlids in the Lower Congo River

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