Perciformes, Cichlidae, Crenicichla tendybaguassu Lucena and Kullander, 1992: first record for Uruguay

Journal of Fish Biology

Duarte²,

Serra³

et al. 2013

Ontogenetic diet shifts were compared among five sympatric pike cichlids Crenicichla in a subtropical South American stream using stable C and N isotopes and tissue stoichiometry (C:N). Within species, stable N isotopes were positively related to body size while C:N showed negative relationships. Stable C isotopes, however, were not related to body size in any species. By modelling the switch to piscivory using gut content-isotope-body size relationships, diet shifts were shown to be species-specific with regard to both rate and degree of piscivory. Compared to other piscivorous lineages, Crenicichla appear to be unusually small-bodied (based on maximum body size). Because of their diversity, abundance and dynamic size-structured functional roles, Crenicichla may exert broad and complex predation pressures on the aquatic community.

Section: Methodsmentioning

confidence: 99%

“…When there is a large size discrepancy between species, they may partition the habitat (Montana & Winemiller, 2009). Subtropical Crenicichla, however, often share microhabitats (Pialek et al ., 2011;Serra et al ., 2011) perhaps owing to their similar body sizes and morphology (Lucena & Kullander, 1992).…”

Section: F U N C T I O Na L Ro L E Smentioning

confidence: 99%

Species‐specific ontogenetic diet shifts among NeotropicalCrenicichla: using stable isotopes and tissue stoichiometry

Journal of Fish Biology

Duarte²,

Serra³

et al. 2013

“…We infer the relationships among five closely related species that are endemic to the Uruguay River (i.e. the URSF): Crenicichla missioneira, C. minuano, C. hadrostigma, C. celidochilus and C. tendybaguassu, which co-occur throughout the drainage and often form mixed species aggregations (de Lucena & Kullander, 1992;de Lucena, 2007;Serra et al, 2011). These species were originally diagnosed based on combinations of morphology, colour pattern and meristics (de Lucena & Kullander, 1992;de Lucena, 2007).…”

Section: Introductionmentioning

confidence: 99%

Phylogenomics of pike cichlids (Cichlidae: Crenicichla): the rapid ecological speciation of an incipient species flock

Journal of Evolutionary Biology

Alda

Duarte

et al. 2018

The rapid rise of phenotypic and ecological diversity in independent lakedwelling groups of cichlids is emblematic of the East African Great Lakes. In this study, we show that similar ecologically based diversification has occurred in pike cichlids (Crenicichla) throughout the Uruguay River drainage of South America. We collected genomic data from nearly 500 ultraconserved element (UCEs) loci and >260 000 base pairs across 33 species, to obtain a phylogenetic hypothesis for the major species groups and to evaluate the relationships and genetic structure among five closely related, endemic, co-occurring species (the Uruguay River species flock; URSF). Additionally, we evaluated ecological divergence of the URSF based on body and lower pharyngeal jaw (LPJ) shape and gut contents. Across the genus, we recovered novel relationships among the species groups. We found strong support for the monophyly of the URSF; however, relationships among these species remain problematic, likely because of the rapid and recent evolution of this clade. Clustered co-ancestry analysis recovered most species as well delimited genetic groups. The URSF species exhibit speciesspecific body and LPJ shapes associated with specialized trophic roles. Collectively, our results suggest that the URSF consists of incipient species that arose via ecological speciation associated with the exploration of novel trophic roles.

“…The Rio Cuareim drains south-western Brazil and north-western Uruguay and is a major tributary to the middle Rio Uruguay. The Rio Cuareim is a fifth-order, clear-water piedmont river characterized by cobble substrates and diverse and highly endemic fish communities (Lucena & Kullander 1992;Zarucki et al 2010;Serra et al 2011;E. The Rio Cuareim is a fifth-order, clear-water piedmont river characterized by cobble substrates and diverse and highly endemic fish communities (Lucena & Kullander 1992;Zarucki et al 2010;Serra et al 2011;E.…”

Section: Study Sitementioning

confidence: 99%

“…Subtropical South American drainages support diverse fish assemblages and display comparatively high degrees of endemism and cryptic diversity (Lucena & Kullander 1992;Pialek et al 2011;Rican et al 2011). Yet, species boundaries, community composition and ecological roles of many subtropical South American fishes are poorly known, and our understanding of food web structure in these streams is extremely limited (Zarucki et al 2010;Serra et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Isotopic trophic guild structure of a diverse subtropical South American fish community

Ecology of Freshwater Fish

Duarte²,

Gangloff

et al. 2012

Self Cite

Characterization of food web structure may provide key insights into ecological function, community or population dynamics and evolutionary forces in aquatic ecosystems. We measured stable isotope ratios of 23 fish species from the Rio Cuareim, a fifth-order tributary of the Rio Uruguay basin, a major drainage of subtropical South America. Our goals were to (i) describe the food web structure, (ii) compare trophic segregation at trophic guild and taxonomic scales and (iii) estimate the relative importance of basal resources supporting fish biomass. Although community-level isotopic overlap was high, trophic guilds and taxonomic groups can be clearly differentiated using stable isotope ratios. Omnivore and herbivore guilds display a broader d 13 C range than insectivore or piscivore guilds. The food chain consists of approximately three trophic levels, and most fishes are supported by algal carbon. Understanding food web structure may be important for future conservation programs in subtropical river systems by identifying top predators, taxa that may occupy unique trophic roles and taxa that directly engage basal resources.