[Ichthyology • 2024] Telmatochromis salzburgeri • 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

Telmatochromis salzburgeri

 Indermaur, Schedel & Ronco, 2024  

 

DOI: doi.org/10.1111/jfb.16042  

Abstract

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). Here, we quantify the morphological diversity of the genus Telmatochromis and the two associated riverine species using a multivariate dataset combining geometric and classical morphometrics, as well as meristics. We identify three distinct morphological clusters: the “Telmatochromis vittatus complex” with highly elongated bodies and short heads, the “Telmatochromis temporalis complex” with deeper bodies, and the two riverine species with intermediate body elongation and large heads. Further, we formally describe the species endemic to the lower Lufubu River as Telmatochromis salzburgeri sp. nov. and reassign N. devosi to Telmatochromis. Telmatochromis devosi comb. nov. differs from all congeners by the absence of bi- and tricuspid teeth in the inner tooth rows of the oral dentition. T. salzburgeri sp. nov. can be distinguished from all other Telmatochromis species by a prominent orange stripe along the base of the dorsal fin and from T. devosi comb. nov. by the relatively smaller size of the lower pharyngeal jaw. Both riverine species differ from all lacustrine Telmatochromis by a lower number of dorsal-fin spines. Additionally, the riverine species can be distinguished from the T. vittatus complex by having larger heads and longer oral jaws, and from the T. temporalis complex by their lower relative body depth. With the inclusion of new riverine members, the genus Telmatochromis is revealed to be more morphologically and ecologically diverse than previously recognized.

Keywords: Africa, Cichlidae, Great Lakes, ichthyofauna, Lufubu River

 

Image series of Telmatochromis salzburgeri sp. nov. 
 (a) Underwater pictures of T. salzburgeri sp. nov. (from top to bottom): a dark specimen, a light specimen, a juvenile, and together with the riverine haplochromine Orthochromis indermauri (images by A.I. and F.D.B.S.).
(b) Photograph of a paratype (NMB-6478, ex. UNIBAS-IC-USH1) in light colouration (top image) and the dark holotype (NHB-6475, ex. UNIBAS-IC-USG9), both taken at the field site from living individuals. The lower two images show the preserved holotype and its X-ray radiograph (images by A.I., F.D.B.S., and Aurelia Wolf).
 (c) Images of the lower pharyngeal jaw of a paratype (ZSM-PIS-044282-DRC-3147) based on a computed tomography (CT) scan (images by F.R.).

Overview of the lamprologine cichlid genus Telmatochromis from Lake Tanganyika and the two riverine taxa: Neolamprologus devosi and Telmatochromis sp. “lufubu”.

 Telmatochromis devosi comb. nov.

reassign Neolamprologus devosi to Telmatochromis.

Telmatochromis salzburgeri sp. nov. 

= Telmatochromis sp. “lufubu”

Differential diagnosis: Adult individuals of T. salzburgeri sp. nov. are distinguished from all other members of the genus Telmatochromis by the presence of a prominent orange stripe along the base of the dorsal fin, extending into the dorsal fin and over the dorsum (see Figure 5a,b). Additionally, T. salzburgeri sp. nov. differs from members of the T. vittatus complex (i.e., T. bifrenatus, T. brichardi, T. vittatus, and allies such as Telmatochromis sp. “longola”) and T. brachygnathus by having a larger head (26.96–30.08 vs. 20.4–26.65 HL%SL) and longer jaws (29.18–40.68 vs. ...

Etymology: The species is named in honor of our friend, colleague, and mentor Prof. Dr. Walter Salzburger for his contributions in advancing the field of evolutionary biology and, in particular, cichlid research in Lake Tanganyika. He has supported several projects and numerous field expeditions of all the authors with great enthusiasm, which led, among many other things, to the description of T. salzburgeri sp. nov.

 

Adrian Indermaur, Frederic D. B. Schedel, Fabrizia Ronco. 2024. 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. Journal of Fish Biology. DOI: doi.org/10.1111/jfb.16042  

[Ichthyology • 2022] Haplochromis aquila, H. kimondo, H. rex, H. simba, etc. • From A Pair to A Dozen: The Piscivorous Species of Haplochromis (Cichlidae) from the Lake Edward System

Haplochromis rex, H. aquila,  

Haplochromis simba, H. kimondo, 

Haplochromis glaucus, H. falcatus,  

Vranken, Van Steenberge, Heylen, Decru & Snoeks, 2022

DOI: 10.5852/ejt.2022.815.1749 

 twitter.com/Phinnochromis 

ABSTRACT

Piscivory is a common trophic niche among cichlids of the East African Great Lakes, including Lakes Edward and George. From these two lakes, we examined the taxonomic diversity of cichlid species with a piscivorous morphology. Prior to this study, two piscivorous species were formally described, Haplochromis squamipinnis and H. mentatus. We redescribe both species and describe an additional ten new species of Haplochromis with a piscivorous morphology: H. latifrons sp. nov., H. rex sp. nov., H. simba sp. nov., H. glaucus sp. nov., H. aquila sp. nov., H. kimondo sp. nov., H. falcatus sp. nov., H. curvidens sp. nov., H. pardus sp. nov., and H. quasimodo sp. nov. All twelve species differ in dominant male colour pattern (unknown for H. latifrons sp. nov. and H. curvidens sp. nov.) and morphological traits. The species can be divided into two morphological groups: the macrodontic piscivores and the microdontic piscivores. This division potentially reflects an ecological differentiation in habitat use, hunting technique, prey species, and prey size. We conclude that some 12–20% of the species from the cichlid assemblage of Lake Edward have a piscivorous morphology.

Keywords: Adaptive radiation, haplochromines, Harpagochromis, Prognathochromis, new species

Phylum Chordata Haeckel, 1874

Class Actinopterygii Klein, 1885

Order Cichliformes Betancur-R et al., 2013

Family Cichlidae Bonaparte, 1840

Subfamily Pseudocrenilabrinae Fowler, 1934

Tribe Haplochromini Poll, 1986

Genus Haplochromis Hilgendorf, 1888

Haplochromis Hilgendorf, 1888: 76 

(as a subgenus of Chromis Cuvier, 1814).

Haplochromis mentatus Regan, 1925

Etymology: Specific name not explained in original description, probably derived from the Latin ‘mentum’ for ‘chin’; probably referring to the protruding lower jaw (i.e., projecting lower jaw sensu Regan 1925).

Haplochromis squamipinnis Regan, 1921

Etymology: Specific name not explained in original description, from the Latin ‘squamus’ for ‘scale’, and ‘pinnis’ for ‘fin’; probably referring to minute scales on basal parts of dorsal and anal fins.

Haplochromis latifrons sp. nov.

Etymology: Specific name from Latin ‘latus’ for ‘wide’ and ‘frons’ for ‘forehead’; referring to very broad interorbital area for a piscivorous species.

Haplochromis rex sp. nov.

Etymology: Specific name from the Latin ‘rex’ for ‘king’ (one that holds a preeminent position); referring to very small eyes, deep cheeks, and strong jaws set with large and acute teeth indicating this piscivore has most specialised morphology among all piscivores from the Lake Edward system to hunt on large prey (Barel et al. 1977).

Haplochromis simba sp. nov.

Etymology: Specific name from Swahili ‘simba’ for ‘lion’; referring to yellow body, orange cheeks that resemble manes, and predatory morphology.

Haplochromis glaucus sp. nov.

Etymology: Specific name from the Latin ‘glaucus’ for ‘greyish blue’; referring to grey and light-blue colour pattern of all adult specimens.

Haplochromis aquila sp. nov.

Etymology: Specific name from the Latin ‘aquila’ for ‘eagle’; referring to predatory morphology and large eyes.

Haplochromis kimondo sp. nov.

Etymology: Specific name from the Swahili ‘kimondo’ for ‘meteor’; referring to blunt head, pyriform body with mid-lateral band, and yellow colouration of ventral part of body.

Haplochromis falcatus sp. nov.

Etymology: Specific name from the Latin ‘falcatus’ for ‘sickle-shaped’; referring to acutely pointed sickle-like outer oral teeth.

Haplochromis rex sp. nov. a. c–d. Photographs of freshly caught specimens. c. Holotype, a dominant male. d. A female (RMCA 2017.006.P.0355; 135.7 mm SL) to illustrate the live colour patterns.  

Haplochromis simba sp. nov. c–d. Photographs of freshly caught specimens. c. Dominant male (RMCA 2016.035.P.0224; 97.9 mm SL). d. Female (RMCA 2018.008.P.0348; 109.0 mm SL) to illustrate the live colour patterns.  

Haplochromis glaucus sp. nov. c–d. Photographs of freshly caught specimens. c. Dominant male,  the  holotype.  d.  Female  (RMCA  2019.002.P.0017;  102.1  mm  SL)  to  illustrate  the  live  colour  patterns.  

Haplochromis aquila sp. nov. c–d. Photographs of freshly caught specimens. c. Dominant male,  the  holotype.  d.  Female  (RMCA  2018.008.P.0352;  108.7  mm  SL)  to  illustrate  the  live  colour  patterns.  
Haplochromis kimondo sp. nov. c–d. Photographs of freshly caught specimens. c. Holotype, a dominant male. d. Female (RMCA 2018.008.P.0364; 128.1 mm SL) to illustrate the live colour patterns.  
Haplochromis falcatus sp. nov. c–d. Photographs of freshly caught specimens. c. Dominant male (RMCA 2017.006.P.0416; 119.1 mm SL). d. Female (RMCA 2016.035.P.0257; 112.8 mm SL) to illustrate the live colour patterns.

Haplochromis curvidens sp. nov. c–d. Photographs of freshly caught specimens. c. Holotype, an adult male. d. Female (RMCA 2018.008.P.0340); 90.2 mm SL) to illustrate the live colour patterns.

Haplochromis quasimodo sp. nov. c–d. Photographs of freshly caught specimens. c. Dominant male (RMCA 2018.008.P(HP3072); 123.7 mm SL). d. Female (RMCA 2018.008.P(HP3064); 116.6 mm SL) to illustrate the live colour patterns.

Haplochromis squamipinnis Regan,  1921. c–d. Photographs of freshly caught specimens. c.  Dominant  male  (RMCA  2016.035.P.0250;  169.7  mm  SL).  d.  Female  (RMCA  2016.035.P(HP823);  129.6 mm SL) to illustrate the live colour patterns. 

 The contrast was slightly enhanced.

Haplochromis curvidens sp. nov. 

Etymology: Specific name from the Latin ‘curvus’ for ‘curvature’, and ‘dentatus’ for ‘tooth’; referring to strongly recurved oral teeth.

Haplochromis pardus sp. nov.

EtymologySpecific name from the Latin ‘pardus’ for ‘leopard’; referring to nearly uniform black to yellow-pink flanks with clear black blotches, i.e., interrupted horizontal and vertical stripes.

Haplochromis quasimodo sp. nov.

Etymology: Specific name from Quasimodo, hunchbacked character in Victor Hugo’s novel ‘Notre-Dame de Paris’ (1831); referring to rather shallow head and deep and rhomboid bodies of large specimens.

Nathan Vranken, Maarten Van Steenberge, Annelies Heylen, Eva Decru and Jos Snoeks. 2022. From A Pair to A Dozen: The Piscivorous Species of Haplochromis (Cichlidae) from the Lake Edward System. European Journal of Taxonomy. 815(1), 1-94. DOI: 10.5852/ejt.2022.815.1749

  twitter.com/Phinnochromis/status/1517159969623207945

[Ichthyology • 2021] Speciation Dynamics and Extent of Parallel Evolution along A Lake-Stream Environmental Contrast in African Cichlid Fishes

Astatotilapia burtoni, Haplochromis stappersii,
Ctenochromis horei, and Pseudocrenilabrus philander

in Weber, Rajkov, ... et Salzburger, 2021 

DOI: 10.1126/sciadv.abg5391 

 twitter.com/WSalzburger 

Artwork by    twitter.com/jehimes

Abstract

Understanding the dynamics of speciation is a central topic in evolutionary biology. Here, we investigated how morphological and genomic differentiation accumulated along the speciation continuum in the African cichlid fish Astatotilapia burtoni. While morphological differentiation was continuously distributed across different lake-stream population pairs, we found that there were two categories with respect to genomic differentiation, suggesting a “gray zone” of speciation at ~0.1% net nucleotide divergence. Genomic differentiation was increased in the presence of divergent selection and drift compared to drift alone. The quantification of phenotypic and genetic parallelism in four cichlid species occurring along a lake-stream environmental contrast revealed parallel and antiparallel components in rapid adaptive divergence, and morphological convergence in species replicates inhabiting the same environments. Furthermore, we show that the extent of parallelism was higher when ancestral populations were more similar. Our study highlights the complementary roles of divergent selection and drift on speciation and parallel evolution.

The study system comprising nine lake-stream population pairs in four cichlid fish species from African Lake Tanganyika and surroundings.
(A) Illustrations of the four species used in this study and a schematic representation of their phylogenetic relationships.
(B) Map of sampling localities and names of the different lake-stream population pairs, that is, systems. Astatotilapia burtoni, Ctenochromis horei, Haplochromis stappersii, and Pseudocrenilabrus philander.

    

CONCLUSION: 

By examining the dynamics of differentiation in the African cichlid A. burtoni, we found that morphological differentiation was continuous along the speciation continuum. Contrastingly, we detected a gap in genomic differentiation that was only partially explained by geographic patterns. Our results, therefore, provide additional support for the hypothesis that there is a tipping point in genomic differentiation during the speciation process (5), suggesting that there might be a threshold of genomic differentiation to delimit species. We further showed that genomic differentiation was accelerated in the presence of both divergent selection and genetic drift, highlighting the combined effect of selective and neutral processes in speciation.

To gain insights into the potential predictability of the speciation process, we investigated the extent of parallel evolution in nine population pairs from four cichlid species that diverged along a similar lake-stream environmental contrast. While pairwise comparisons failed to identify strong signatures of phenotypic and genomic parallelism, multivariate analyses uncovered major axes of shared evolutionary changes along the lake-stream contrast. Last, we found that levels of parallelism were higher between closely related and, hence, genetically more similar population pairs. While the speciation process is overall difficult to predict, our results support the view that evolution can be predictable to a certain extent if appropriate models and data are used (56). To conclude, our study corroborates that contingency plays an important role in speciation and that speciation is a complex product of differentiation trajectories through multivariate space and time.

Alexandra A.-T. Weber, Jelena Rajkov, Kolja Smailus, Bernd Egger and Walter Salzburger. 2021 Speciation Dynamics and Extent of Parallel Evolution along A Lake-Stream Environmental Contrast in African Cichlid Fishes. SCIENCE ADVANCES. 7: 45. DOI: 10.1126/sciadv.abg5391

  twitter.com/WSalzburger/status/1456190934257917952

   twitter.com/jehimes/status/1456038575984689152

[Ichthyology • 2016] Phylogeny and Phylogeography of Altolamprologus: Ancient Introgression and Recent Divergence in A Rock-Dwelling Lake Tanganyika Cichlid Genus

Fig. 1 A Typical representatives of Altolamprologus calvus, A. compressiceps and A. sp. “shell”. Photographs courtesy of Wolfgang Gessl (www.pisces.at). B Map of Lake Tanganyika with sampling localities. Numbers in parentheses refer to sample sizes; different colours indicate different species (red, A. calvus; blue, A. compressiceps; green, A. sp. “shell”). The three deepwater basins are indicated by grey shading

DOI: 10.1007/s10750-016-2896-2

Abstract

Stenotopic specialization to a fragmented habitat promotes the evolution of genetic structure. It is not yet clear whether small-scale population structure generally translates into large-scale intraspecific divergence. In the present survey of mitochondrial genetic structure in the Lake Tanganyika endemic Altolamprologus (Teleostei, Cichlidae), a rock-dwelling cichlid genus comprising A. compressiceps and A. calvus, habitat-induced population fragmentation contrasts with weak phylogeographic structure and recent divergence among genetic clades. Low rates of dispersal, perhaps along gastropod shell beds that connect patches of rocky habitat, and periodic secondary contact during lake level fluctuations are apparently sufficient to maintain genetic connectivity within each of the two Altolamprologus species. The picture of genetic cohesion was interrupted by a single highly divergent haplotype clade in A. compressiceps restricted to the northern part of the lake. Comparisons between mitochondrial and nuclear phylogenetic reconstructions suggested that the divergent mitochondrial clade originated from ancient interspecific introgression. Finally, ‘isolation-with-migration’ models indicated that divergence between the two Altolamprologus species was recent (67–142 KYA) and proceeded with little if any gene flow. As in other rock-dwelling cichlids, recent population expansions were inferred in both Altolamprologus species, which may be connected with drastic lake level fluctuations.

Keywords: Cichlidae, Mitochondrial replacement, Phylogeography, Lake level fluctuations, Lamprologini, Hybridization

Conclusions

In numerous studies of lacustrine cichlids, the species’ ecological specialization predicts population genetic differentiation on small geographic scales. The present study shows that population fragmentation and small-scale differentiation do not necessarily translate into distinct lake-wide structure. The discrepancy between population genetic and phylogeographic structures may arise from the different time scales relevant for the evolution of either. In particular, population differentiation—i.e. significant differences in allele and haplotype frequencies between populations—can evolve despite low gene flow within relatively short periods of time. Over longer periods of time, however, even low levels of gene flow can mediate genetic connectivity across substantial geographic distances.

Stephan Koblmüller, Bruno Nevado, Lawrence Makasa, Maarten Van Steenberge, Maarten P. M. Vanhove, Erik Verheyen, Christian Sturmbauer and Kristina M. Sefc. 2016. Phylogeny and Phylogeography of Altolamprologus: Ancient Introgression and Recent Divergence in A Rock-Dwelling Lake Tanganyika Cichlid Genus. Hydrobiologia [ADVANCES IN CICHLID RESEARCH II]. DOI: 10.1007/s10750-016-2896-2