Papers by Melanie Stiassny
Page 428. MLJ Stiassny EO Wiley GD Johnson MR de Carvalho 24 Gnathostome Fishes Gnathostomata are... more Page 428. MLJ Stiassny EO Wiley GD Johnson MR de Carvalho 24 Gnathostome Fishes Gnathostomata are a species-rich assemblage that, with the exclusion of the Petromyzontiformes (lampreys, 45 spp.), rep-resents all living members of Vertebrata. ...
Scientific American, 1999
T he waters of Lake Tanganyika are clear, dark and deep, but the shallow, sunlit edges are where ... more T he waters of Lake Tanganyika are clear, dark and deep, but the shallow, sunlit edges are where most of the cichlids live. Brown or green Eretmodus algae scrapers, covered with blue spots, thrive among the breaking waves; the turbulent water pushes their rounded backs onto the rock surfaces instead of pulling them off. These fish nip algae off the rocks with their chisel-like teeth. Their neighbors the Tanganicodus insect pickers also have round backs. But the pointed heads, sharp snouts and long, fine teeth of these cichlids are adapted to plucking insect larvae from within the crevices. In calmer waters, old snail shells are strewn on 64 Female Haplotaxodon tricoti broods her young Color morphs of Tropheus duboisi live in separate rock piles Cichlids of the Rift Lakes The extraordinary diversity of cichlid fishes challenges entrenched ideas of how quickly new species can arise
American Museum Novitates, Jun 1, 2007
Congochromis, a new cichlid genus, is described on the basis of a suite of anatomical features of... more Congochromis, a new cichlid genus, is described on the basis of a suite of anatomical features of the cephalic laterosensory system, infraorbital series, oral dentition, and squamation. As recognized herein, Congochromis comprises three species formerly included in the genus Nanochromis (N. squamiceps, N. dimidiatus, and N. sabinae) and a new species from the vicinity of Kisangani (Stanleyville) on the upper Congo River. Diagnostic features for Congochromis and Nanochromis s.str. are provided. Congochromis pugnatus, n.sp. is diagnosed by the possession of a distinctive pattern of hypural fusion, a strongly inclined lower jaw, and an expanded cheek musculature.
BMC Evolutionary Biology, 2010
Background: It is hypothesized that one of the mechanisms promoting diversification in cichlid fi... more Background: It is hypothesized that one of the mechanisms promoting diversification in cichlid fishes in the African Great Lakes has been the well-documented pattern of philopatry along shoreline habitats leading to high levels of genetic isolation among populations. However lake habitats are not the only centers of cichlid biodiversity-certain African rivers also contain large numbers of narrowly endemic species. Patterns of isolation and divergence in these systems have tended to be overlooked and are not well understood. Results: We examined genetic and morphological divergence among populations of two narrowly endemic cichlid species, Teleogramma depressum and Lamprologus tigripictilis, from a 100 km stretch of the lower Congo River using both nDNA microsatellites and mtDNA markers along with coordinate-based morphological techniques. In L. tigripictilis, the strongest genetic break was concordant with measurable phenotypic divergence but no morphological disjunction was detected for T. depressum despite significant differentiation at mtDNA and nDNA microsatellite markers. Conclusions: The genetic markers revealed patterns of philopatry and estimates of genetic isolation that are among the highest reported for any African cichlid species over a comparable geographic scale. We hypothesize that the high levels of philopatry observed are generated and maintained by the extreme hydrology of the lower Congo River.
Zenodo (CERN European Organization for Nuclear Research), Dec 31, 2007
A new dwarf alestid from the vicinity of Inga on the lower Congo River, Bas Congo Province, Democ... more A new dwarf alestid from the vicinity of Inga on the lower Congo River, Bas Congo Province, Democratic Republic of Congo is described. Assignment of the new taxon to the poorly defined genus, Micralestes, is discussed and justified on the basis of available morphological character data. With the recognition of Micralestes schelly sp. nov., a total of six Micralestes are now known to inhabit the 350 km stretch of the Congo River from Pool Malebo to Boma near the river's estuary. These are Micralestes acutidens (Peters, 1852), Micralestes humilis Boulenger, 1899, Micralestes lualabae Poll, 1967, Micralestes holargyreus (GĂ¼nther, 1873), Micralestes stormsi Boulenger, 1902, and the new species Micralestes schelly. Of these Micralestes schelly and Micralestes holargyreus are considered herein as restricted-range endemics of the lower Congo River. An illustrated key to Micralestes of the lower Congo River is provided.
Frontiers in Environmental Science
Characterizing functional freshwater biodiversity patterns and understanding community determinan... more Characterizing functional freshwater biodiversity patterns and understanding community determinants can aid in predicting changes and prioritizing specific conservation management actions. Afrotropical freshwater systems support diverse ecological communities, including many taxonomically undescribed species, yet few studies have been undertaken in this region and they remain poorly understood. Here, we use functional trait-based approaches to describe the functional diversity of fish assemblages in the Republic of Congo (west Central Africa) from the headwaters of a large basin (upper basin) to the coastal plains (lower basin). Functional traits were assessed using multivariate ordination, and functional diversity was calculated using functional trait-space occupation. We investigated if fish β diversity is nested regionally and at a basin-scale to understand if species assemblages exhibit non-random or environmental filtering patterns. Trait-environment relationships were modeled ...
Systematic Biology
African cichlids (subfamily: Pseudocrenilabrinae) are among the most diverse vertebrates, and the... more African cichlids (subfamily: Pseudocrenilabrinae) are among the most diverse vertebrates, and their propensity for repeated rapid radiation has made them a celebrated model system in evolutionary research. Nonetheless, despite numerous studies, phylogenetic uncertainty persists, and riverine lineages remain comparatively underrepresented in higher-level phylogenetic studies. Heterogeneous gene histories resulting from incomplete lineage sorting (ILS) and hybridization are likely sources of uncertainty, especially during episodes of rapid speciation. We investigate the relationships of Pseudocrenilabrinae and its close relatives while accounting for multiple sources of genetic discordance using species tree and hybrid network analyses with hundreds of single-copy exons. We improve sequence recovery for distant relatives, thereby extending the taxonomic reach of our probes, with a hybrid reference guided/de novo assembly approach. Our analyses provide robust hypotheses for most higher...
The Behavior, Ecology and Evolution of Cichlid Fishes, 2021
American Museum Novitates, 2019
A new procatopodid, assigned to the genus Poropanchax, is described from a wetland habitat locate... more A new procatopodid, assigned to the genus Poropanchax, is described from a wetland habitat located adjacent to the Inga Falls in Lower Congo. Poropanchax pepo, new species, is distinguished from all congeners by a combination of characters including a higher D/A ratio, rounded anal and dorsal fins, a humeral blotch in males, and the absence of a sharp ventral process on the basipterygium. The finding of a Poropanchax species in Lower Congo was unexpected, since the closest known congeneric population is located in northwestern Gabon, some 700 kilometers to the north. As recognized herein the genus Poropanchax is a clade comprised of five species geographically restricted to humid coastal regions of west and west-central Africa.
Journal of Fish Biology, 2019
A new species of the chromidotilapiine genus Thysochromis, is described from the Noumbi and Kouil... more A new species of the chromidotilapiine genus Thysochromis, is described from the Noumbi and Kouilou River drainages in the Republic of Congo. Based on the current investigation, Thysochromis is resolved as containing two geographically disjunct species, T. ansorgii from localities in the upper Guinean ichthyofaunal province (Ivory Coast, Ghana, Benin and Nigeria) and Thysochromis emili sp. nov. restricted to coastal regions of the Republic of Congo in the lower Guinean province.
Zootaxa, 2010
A new species of cichlid fish is described from a small, endorheic lake (Lake Abaeded), situated ... more A new species of cichlid fish is described from a small, endorheic lake (Lake Abaeded), situated some 30 m below sea level in the Danakil Depression of Eritrea (East Africa). Danakilia dinicolai is readily distinguished from its congener, D. franchettii, on the basis of body proportions and in the possession of markedly longer pectoral fins at all sizes. Additionally, oral dentition is more robust than that of its congener, and the lower pharyngeal jaw is markedly hypertrophied and covered with considerably finer and more densely implanted teeth on the posterior field of the jaw.
Nature Ecology & Evolution, 2017
Among substrate-spawning cichlids two quite distinct egg attachment systems are described using s... more Among substrate-spawning cichlids two quite distinct egg attachment systems are described using scanning electron microscopy. In the phylogenetically primitive Asian and Madagascan cichlids examined, the eggs are nonadhesive and are attached to the substrate, or to one another, by a tuft of filaments arising from the pole opposite the micropyle. A different system appears to characterize the Afro-Neotropical clade; in these fishes the eggs are highly adhesive with attachment to the substrate facilitated by a thick mucus layer and numerous surface filaments. Outgroup data from the Pomacentridae are equivocal and do not permit conclusive assignment ofpolarity for variation within the Cichlidae. However, while we are unable to determine the plesiomorphic cichlid attachment system, the presence of a distinct mucus-filament attachment system is unique among percomorph taxa examined to date and is interpreted here as further support for the monophyly of the Afro-Neotropical Cichlidae.
PLOS ONE, 2015
The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of... more The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of the Gulf of Mexico and is of commercial significance in Florida, where it is harvested for the aquarium and curio trades. Despite its regional importance, the genetic structure of dwarf seahorse populations remains largely unknown. As an aid to ongoing conservation efforts, we employed three commonly applied mtDNA markers (ND4, DLoop and CO1) to investigate the genetic structuring of H. zosterae in Florida using samples collected throughout its range in the state. A total of 1450 bp provided sufficient resolution to delineate four populations of dwarf seahorses, as indicated by significant fixation indices. Despite an overall significant population structure, we observed evidence of interbreeding between individuals from geographically distant sites, supporting the hypothesis that rafting serves to maintain a degree of population connectivity. All individuals collected from Pensacola belong to a single distinct subpopulation, which is highly differentiated from the rest of Floridian dwarf seahorses sampled. Our findings highlight the utility of mtDNA markers in evaluating barriers to gene flow and identifying genetically distinct populations, which are vital to the development of comprehensive conservation strategies for exploited taxa.
Environmental Biology of Fishes, 2015
The Congo River Lamprologus are revised and two new species are described. Lamprologus teugelsi, ... more The Congo River Lamprologus are revised and two new species are described. Lamprologus teugelsi, n.sp., from Malebo Pool and the lower Congo River rapids, and L. tigripictilis, n.sp., from the lower Congo River rapids, are readily distinguished from the remaining Congo River Lamprologus based on counts, measurements, osteology, and color pattern. Monophyly of the Congo River Lamprologus species is tentatively accepted and a key to the group is provided. All available collection localities for re-identified Lamprologus material from the Congo River are plotted for each species. Maps of collection localities reveal large distributional voids, suggesting that Congo River lamprologine diversity remains incompletely sampled.
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Papers by Melanie Stiassny