@article{AmenNagelHedtetal.2020,
  author    = {Amen, Rahma and Nagel, Rebecca and Hedt, Maximilian and Kirschbaum, Frank and Tiedemann, Ralph},
  title     = {Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences},
  series = {Evolutionary Ecology},
  volume    = {34},
  journal   = {Evolutionary Ecology},
  number    = {3},
  publisher = {Springer Science},
  address   = {Dordrecht},
  issn      = {0269-7653},
  doi       = {10.1007/s10682-020-10043-3},
  pages     = {427 -- 437},
  year      = {2020},
  abstract  = {Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype-environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated.},
  language  = {en}
}
@article{ParaskevopoulouTiedemannWeithoff2018,
  author    = {Paraskevopoulou, Sofia and Tiedemann, Ralph and Weithoff, Guntram},
  title     = {Differential response to heat stress among evolutionary lineages of an aquatic invertebrate species complex},
  series = {Biology letters},
  volume    = {14},
  journal   = {Biology letters},
  number    = {11},
  publisher = {Royal Society},
  address   = {London},
  issn      = {1744-9561},
  doi       = {10.1098/rsbl.2018.0498},
  pages     = {5},
  year      = {2018},
  abstract  = {Under global warming scenarios, rising temperatures can constitute heat stress to which species may respond differentially. Within a described species, knowledge on cryptic diversity is of further relevance, as different lineages/cryptic species may respond differentially to environmental change. The Brachionus calyciflorus species complex (Rotifera), which was recently described using integrative taxonomy, is an essential component of aquatic ecosystems. Here, we tested the hypothesis that these (formerly cryptic) species differ in their heat tolerance. We assigned 47 clones with nuclear ITS1 (nuITS1) and mitochondrial COI (mtCOI) markers to evolutionary lineages, now named B. calyciflorus sensu stricto (s.s.) and B. fernandoi. We selected 15 representative clones and assessed their heat tolerance as a bi-dimensional phenotypic trait affected by both the intensity and duration of heat stress. We found two distinct groups, with B. calyciflorus s.s. clones having higher heat tolerance than the novel species B. fernandoi. This apparent temperature specialization among former cryptic species underscores the necessity of a sound species delimitation and assignment, when organismal responses to environmental changes are investigated.},
  language  = {en}
}
@article{FiorentinoManganelliGiustietal.2013,
  author    = {Fiorentino, V. and Manganelli, Giuseppe and Giusti, Folco and Tiedemann, Ralph and Ketmaier, Valerino},
  title     = {A question of time the land snail Murella muralis (Gastropoda: Pulmonata) reveals constraints on past ecological speciation},
  series = {Molecular ecology},
  volume    = {22},
  journal   = {Molecular ecology},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0962-1083},
  doi       = {10.1111/mec.12107},
  pages     = {170 -- 186},
  year      = {2013},
  abstract  = {The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial-temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces. To investigate these questions, we quantified variation on a fine geographical scale analysing morphological (shell) and genetic data sets coupled with environmental data in the land snail Murella muralis, endemic to the Mediterranean island of Sicily. Analysis of a fragment of the mitochondrial DNA cytochrome oxidase I gene (COI) and eight nuclear microsatellite loci showed that genetic variation is highly structured at a very fine spatial scale by local palaeogeographical events and historical population dynamics. Molecular clock estimates, calibrated here specifically for Tyrrhenian land snails, provided a framework of palaeogeographical events responsible for the observed geographical variations and migration routes. Finally, we showed for the first time well-documented lines of evidence of selection in the past, which explains divergence of land snail shell shapes. We suggest that time and palaeogeographical history acted as constraints in the progress along the ecological speciation continuum. Our study shows that testing for correlation among palaeogeography, morphology and genetic data on a fine geographical scale provides information fundamental for a detailed understanding of ecological speciation processes.},
  language  = {en}
}