Body shape variation in relation to resource partitioning within cichlid trophic guilds coexisting along the rocky shore of Lake Malawi

2003 ◽  
Vol 53 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Daud Kassam ◽  
Kosaku Yamaoka ◽  
Aggrey Ambali ◽  
Dean Adams
Keyword(s):  
Resource Partitioning ◽  
Body Shape ◽  
Lake Malawi ◽  
Rocky Shores ◽  
Shape Variation ◽  
Cichlid Species ◽  
Body Design ◽  
Ctenopharynx Pictus ◽  
Temporal Dimensions

AbstractTo appreciate better how cichlids segregate along the trophic, spatial and temporal dimensions, it is necessary to understand the cichlids' body design, and its role in resource partitioning. We investigated body shape variation, quantified using landmark-based geometric morphometrics, among cichlid species belonging to algal and zooplankton feeders coexisting along the rocky shores of Lake Malawi, in order to elucidate the adaptive significance of body shape. Significant differences were found within zooplankton feeders in which Copadichromis borleyi had a shorter gape, smaller eyes and shorter caudal peduncle relative to Ctenopharynx pictus and, within algal feeders, Labeotropheus fuelleborni had a shorter and inferior subterminal gape, and shorter head relative to Petrotilapia genalutea. Variation among species is discussed with reference to trophic and feeding microhabitat differentiation which enables us to appreciate the role of body shape in enhancing ecological separation, and thus leads to coexistence among cichlid species.

scholarly journals Genetic basis of body shape variation along the benthic-pelagic axis in cichlid fishes

2021 ◽  
Author(s):  
Leah DeLorenzo ◽  
Destiny Mathews ◽  
A. Allyson Brandon ◽  
Mansi Joglekar ◽  
Aldo Carmona Baez ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Body Shape ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Lake Malawi ◽  
Shape Variation ◽  
East African ◽  
Cichlid Fishes ◽  
African Rift ◽  
Two Hybrid

Divergence along the benthic-pelagic axis is one of the most widespread and repeated patterns of morphological variation in fishes, producing body shape diversity associated with ecology and swimming mechanics. This ecological shift is also the first stage of the explosive adaptive radiation of cichlid fishes in the East African Rift Lakes. We use two hybrid crosses of cichlids (Metriaclima sp. x Aulonocara sp. and Labidochromis sp. x Labeotropheus sp., >975 animals total) along the benthic-pelagic ecomorphological axis to determine the genetic basis of body shape diversification. Using a series of both linear and geometric shape measurements, we identify 55 quantitative trait loci (QTL) that underlie various aspects of body shape variation associated with benthic-pelagic divergence. These QTL are spread throughout the genome, each explain 3.0-7.2% of phenotypic variation, and are largely modular. Further, QTL are distinct both between these two crosses of Lake Malawi cichlids and compared to previously identified QTL for body shape in fishes such as sticklebacks. We find that body shape is controlled by many genes of small effects. In all, we find that convergent benthic and pelagic body phenotypes commonly observed across fish clades are most likely due to distinct genetic and molecular mechanisms.

scholarly journals Astiotrema turneri n. sp. (Digenea: Plagiorchiidae) from cichlid fishes (Cichlidae: Perciformes) of Lake Malawi, south-eastern Africa

Zootaxa ◽  
2006 ◽  
Vol 1319 (1) ◽  
pp. 43 ◽  
Author(s):  
RODNEY A. BRAY ◽  
COCK VAN OOSTERHOUT ◽  
JONATAN BLAIS ◽  
JOANNE CABLE
Keyword(s):  
Ventral Sucker ◽  
Body Shape ◽  
Lake Malawi ◽  
Eastern Africa ◽  
Intestinal Bifurcation ◽  
Cichlid Species ◽  
Cichlid Fishes ◽  
South Eastern

Astiotrema turneri n. sp. is described from the cichlid species Pseudotropheus zebra, P. emmiltos, Labeotropheus trewavasae and Melanochromis vermivorus from Lake Malawi. It differs from Astiotrema reniferum (as described by Yeh & Fotedar 1958) in its distinctly broader body, the much smaller cirrus-sac, its oblique testes, the shorter ventral sucker to ovary distance, the vitellarium reaching into the forebody and the extracaecal uterus; from Astiotrema impletum in the sucker-ratio, the longer caeca, the smaller cirrus-sac and the extracaecal uterus; and from Glossidium pedatum (and its probable synonyms Astiotrema lazeri and Afromacroderoides lazerae) in its much broader body shape, in its distinct oesophagus, the intestinal bifurcation in the posterior forebody, in the distinctly oblique testes, the extracaecal uterus and the vitellarium reaching well into the forebody.

scholarly journals Female preference for conspecific males based on olfactory cues in a Lake Malawi cichlid fish

2005 ◽  
Vol 1 (4) ◽  
pp. 411-414 ◽  
Author(s):  
Martin Plenderleith ◽  
Cock van Oosterhout ◽  
Rosanna L Robinson ◽  
George F Turner
Keyword(s):  
Cichlid Fish ◽  
Mate Recognition ◽  
Lake Malawi ◽  
Olfactory Cues ◽  
Species Flock ◽  
East African ◽  
Significant Preference ◽  
African Species ◽  
Cichlid Species

Research on reproductive isolation in African cichlid fishes has largely focused on the role of nuptial colours, but other sensory modes may play an important role in mate choice. Here, we compare the relative importance of visual and olfactory cues in mate recognition by females of a Lake Malawi cichlid species. Female Pseudotropheus emmiltos were given a choice of spawning next to a conspecific male or a male of the closely-related sympatric Pseudotropheus fainzilberi . Significant preference for conspecific males only occurred when olfactory cues were present. This suggests that divergence of olfactory signals may have been an important influence on the explosive radiation of the East African species flock.

Functional significance of variation in trophic morphology within feeding microhabitat-differentiated cichlid species in Lake Malawi

2004 ◽  
Vol 54 (1) ◽  
pp. 77-90 ◽  
Author(s):  
Dean Adams ◽  
Kosaku Yamaoka ◽  
Daud Kassam
Keyword(s):  
Trophic Guilds ◽  
Shape Variation ◽  
Head Region ◽  
Trophic Guild ◽  
Ecological Segregation ◽  
Cichlid Species ◽  
Articular Process ◽  
Trophic Morphology ◽  
Lower Jaw ◽  
Ctenopharynx Pictus

AbstractShape variation in trophic morphology between species in two trophic guilds (zooplankton and epilithic algal feeders) was investigated using landmark-based geometric morphometrics. Three disarticulated bone elements from the head region were examined; the neurocranium, the premaxilla and lower jaw. From separate analyses of each bone element, significant shape variation was identified between species in each trophic guild. The deformation grids generated revealed that, for the zooplankton feeders, Ctenopharynx pictus has a longer neurocranium, a longer and ventrally directed vomer, a larger orbit, a shorter ascending arm, a shorter maxillad spine, and a more compressed articular bone relative to Copadichromis borleyi. In algal feeders, Labeotropheus fuelleborni has a shorter neurocranium, a smaller orbit, a ventrally directed vomer, a longer ascending arm, a shorter dentigerous arm, increased height of the articular process, and a more elongated dentary than Petrotilapia genalutea. Observed anatomical differences are discussed in terms of function, specifically with respect to the feeding microhabitat differentiation between species in each trophic guild. These differences enable us to appreciate the role that trophic morphology plays in enhancing ecological segregation, leading to coexistence of the species.

Learning body shape variation in physics-based characters

2019 ◽  
Vol 38 (6) ◽  
pp. 1-12 ◽  
Author(s):  
Jungdam Won ◽  
Jehee Lee
Keyword(s):  
Body Shape ◽  
Shape Variation

scholarly journals Temporary events and spaces in the Swedish primary art market

2014 ◽  
Vol 58 (1) ◽  
Author(s):  
Johan Jansson
Keyword(s):  
New York ◽  
Economic Geography ◽  
Art Market ◽  
Economic Activities ◽  
Art Exhibition ◽  
Art Galleries ◽  
Economic Values ◽  
Theoretical Perspectives ◽  
Temporal Dimensions

AbstractTraditionally, the art market is associated with specific cities or art districts; typically there are internationally renowned locations like Paris, New York and Berlin. However, taking a closer look at the art markets, it is rather the temporal dimensions that are striking. Art market actors (e. g. artists, critics, gallerists, buyers, collectors, curators) are gathering in temporary locations and at temporary events such as art exhibition openings, art fairs, auctions, performances and vernissages. Within economic geography literature, the role of temporary spaces and events has been increasingly discussed in relation to economic activities and their performance, efficiency and creativity. An important insight gained in this literature is how temporary events, despite their short-lived existence, create microcosms of an industry or sector. Some temporary events even gather enough resources, skills and power to become field-configuring. In this paper, the primary art market will be discussed from the theoretical perspectives of value-making processes, temporary spaces and events, and field-configuring events. More specifically, the study focuses on temporary spaces important to galleries involved in selling and promoting primary art and artists. It focuses on how temporary spaces constitute both a characteristic feature of the art market and important spaces for creating both cultural and economic values. Empirically, this paper is based on a study of the Swedish primary art galleries and in particular it deals with primary art galleries located in Stockholm, and studies how they use temporary spaces and events in creating both cultural and economic values to themselves, the artists and their artworks. Three empirical examples characteristic to primary art galleries are examined; the opening, the art fair and the mobile art district.

An exposure scale for marine shores in western Norway

1978 ◽  
Vol 58 (4) ◽  
pp. 975-996 ◽  
Author(s):  
D. H. Dalby ◽  
E. B. Cowell ◽  
W. J. Syratt ◽  
J. H. Crothers
Keyword(s):  
Species Abundance ◽  
Shell Shape ◽  
Rocky Shores ◽  
Shape Variation ◽  
Nucella Lapillus ◽  
Extended Form ◽  
Independent Evidence ◽  
The North ◽  
Western Norway ◽  
The North Sea

A rocky shore exposure scale, intended primarily for use in the Fensfjord area, Western Norway, has been prepared. This scale is developed from an earlier scale devised by Ballantine for Milford Haven, Wales, making use of species abundance curves along the wave exposure gradient. Independent evidence for the validity of the scale is provided by shell shape variation in Nucella lapillus and by the height of the black lichen zone in the supralittoral fringe. The successive steps in the preparation of the scale are outlined, definitions of the exposure grades are given in tabular form for the restricted set of species analysed numerically and descriptions are provided in an extended form to provide a fuller picture for users of the scale. It is believed that the scale will prove applicable to other rocky shores around the North Sea.

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