Bernd Kramer's research while affiliated with Universität Regensburg and other places

... The taxon was treated as a synonym of the West African species Marcusenius senegalensis (Steindachner 1870), but as a valid subspecies (Gosse 1984: 89, Lévêque et al. 1991. Marcusenius senegalensis gracilis (Pellegrin 1922) has precedence over Marcusenius gracilis Kramer 2013, and the latter must be renamed when both taxa are classified in genus Marcusenius. Marcusenius elegans nom. ...

... We obtained habitat data for all 261 valid species of Gymnotiformes and 199/234 (85.0%) valid species of Mormyroidea from museum collection records and published literature reports (Corbet 1961, Greenwood 1966, Ita 1978, Banister & Bailey 1979, Møller et al. 1979, Balon & Stewart 1983, Gosse 1984, Lévêque et al. 1991, Bailey 1994, Paugy et al. 1994, Kirschbaum 1995, Sanyanga et al. 1995, Ikomi 1996, van der Bank & Kramer 1996, Bigorne 2003a, Bigorne 2003b, Seegers et al. 2003, Lavoué et al. 2004, Sullivan & Hopkins 2005, Konan et al. 2006, Hopkins et al. 2007, Albert & Reis 2011, Lavoué 2011, Lavoué 2012, Kramer 2013, Monsembula Iyaba et al. 2013, Lavoué & Sullivan 2014, Lamanna et al. 2016, Lavoué 2016, Sullivan et al. 2016, Rich et al. 2017, Albert et al. 2020, Mulelenu et al. 2020, Fricke et al. 2021. We used primary literature when available for all species, but there is more primary literature available for Gymnotiformes than Mormyroidea. ...

... 2022). However, recent studies have shown that this species is native to the Zambezi ichthyofaunal province (Kramer et al., 2012). Being a riverine species, this new evidence suggests that presence of this species in Uganda is unlikely. ...

... Petrocephaline behavior has not been studied as thoroughly, but laboratory observations have documented territoriality similar to that seen in clade-A species (Lamml and Kramer, 2008; Scheffel and Kramer, 2000). However, these studies were performed in tanks housing relatively small numbers of conspecifics. ...

... disparity of head shape, craniofacial phenotypes, and electric signal waveforms (Ford et al. in review;Fricke et al. 2021;Lamanna et al. 2016;Lavoué et al. 2004;Kramer 2013;van der Bank and Kramer 1996;). Mormyrids have a relatively large brain as compared to their body size, hypothesized to be connected to cognitive functions such as environmental mapping and signal recognition (Butler and Hodos 2005;Nilsson 1996 electroreception and electrogeneration) and the genetic basis of signal diversity, and have found evidence for convergence in these areas (Bullock et al. 1983;Lavoue et al. 2012;Wang and Yang 2021;Zakon et al. 2006). ...

... Most commonly, studies report whether territory owners respond differently to familiar versus unfamiliar conspecifics (e.g., Jaeger 1981; Lesbarrères and Lodé 2002;Bee et al. 2016). The second prediction is that territory owners should respond more aggressively to a cheating neighbor that moves to a location different from the agreed-upon boundary than to the same neighbor that is cooperating by remaining behind the agreed-upon boundary (e.g., Hanika and Kramer 2005;Carazo et al. 2008;Briefer et al. 2009). For the latter prediction, a spatial learning component must be involved. ...

... Recognition of mates from others is crucial for monogamous species to maintain their long-term pair bonds (Boyle and Tricas, 2014). The cues underlying individual recognition vary, and include visual (Chan et al., 2020), olfactory (Blengini et al., 2018), acoustic (Curé et al., 2012), behavioral (Hemptinne et al., 1998) and electrosensory (Painter and Kramer, 2003) cues. In the present study, through Experiments 1 Table 1 The blocking and retention of cues in the four groups of Experiment 2. ′′ ¡ ′′ indicates that the cue was blocked, and ′′ + ′′ indicates that the cue was retained. ...

... In addition to the species-specific EOD waveform, species recognition in mormyrid fishes may be supported by various sensory modalities, including acoustic signals (Pollimyrus [48,49], Brienomyrus [50] and Gnathonemus [51]) and the lateral line or visual cues (Gnathonemus [52,53]). While little information is available about the function of olfactory systems or the production/detection of hormonal pheromones in mormyrids, pheromones are known to mediate species and mate recognition in numerous other teleost fishes [54]. ...

... A communication context where EODs constitute the primary communication channel for mormyrids is sexual signaling, where males and females actively interact with one another (Bratton and Kramer 1989;Werneyer and Kramer 2005;Wong and Hopkins 2007). More specifically, many experimental studies have shown that both males and females exhibit mating preferences for specific EOD waveform features (Hopkins and Bass 1981;Arnegard et al. 2006;Machnik and Kramer 2008;Markowski et al. 2008;Feulner et al. 2009a;Machnik et al. 2010;Nagel et al. 2018a,b). Among Paramormyrops species, field and laboratory playback experiments have also revealed strong preferences for speciesspecific EOD waveforms during courtship (Hopkins and Bass 1981), indicating that EODs are most likely involved in maintaining prezygotic isolation between closely related species. ...

... The role of these topographic barriers has been confirmed by previous studies (e.g. Jackson 1961, Jubb 1967, Bell-Cross 1972, Kramer and van der Bank 2011) that have consistently shown that the MIZ is relatively poor in species richness compared to the UPZ and KAF. Although there is literature that minimizes the role of the Victoria Falls as a biogeographical barrier (see Balon 1974), citing the presence of species otherwise distinct to the UPZ below the falls, this has been disputed by recent studies (e.g. ...