Sympatry and syntopy of cichlids (Teleostei: Cichlidae) in the Selva Central, upper Ucayali river basin, Peru

Abstract

Abstract. Sympatry and syntopy are rare among congeneric cichlids in the Neotropics. Among Peruvian Amazonian cichlids congeneric syntopy has so far been reported in only 1 case known from a single locality. Based on thorough exploration of a new locality I refute the syntopy of the 2 species involved: Bujurquina robusta (Kullander, 1986) is a mouth-bay species while B. labiosa (Kullander, 1986) is an upland species. I demonstrate the generality of this ecological allotopy with further examples from a second study area including a different set of species.

Repeated ecomorphological divergence in Bujurquina (Teleostei: Cichlidae) body shape

“…Bujurquina species are highly philopatric, show small-scale endemism, strong adaptation to local environmental conditions, and are highly diverse in the lowlands and Andean foothills (unlike Apistogramma , the other species-rich genus of the western Amazon). Furthermore, it is the only cichlid genus whose geographic distribution and highest diversity is centred in the western Amazon and whose distribution and endemism follows the putative course of the paleo-Amazon (Kullander 1986, Říčan 2017, Říčan et al 2022). Consequently, Bujurquina species have a distribution unlike any other large South American cichlid genera, which generally (not Apistogramma ) show the highest diversity and endemism in the older eastern Amazon within the Brazilian and Guiana shield regions (Stawikowski & Werner 1998, 2004, Kullander et al 2018, Van der Sleen & Albert 2018, Říčan et al 2021).…”

“…The two zones host different Bujurquina faunas, with the lowland species usually not found in the adjacent foothills and vice versa (Kullander 1986, Říčan et al 2022). Thus, foothill areas have a different Bujurquina fauna than lowland areas within the same river basins, at least in the centre of known Bujurquina diversity in Peru, where Kullander (1986) first proposed the hypothesis (Říčan 2017), and in Ecuador (Říčan et al 2022).…”

“…Typical highland species of Bujurquina occur in the Andean foothills, generally between 400 m and up ca. 1,200 m elevation, in streams and rivers with seasonally clear and permanently running water, with river beds composed of stones and pebbles (Kullander 1986, Crampton 2011, Říčan 2017; Figs. 1-2, Figs.…”

“…S1-S2), thus enabling us to explore diversity within the genus and test evolutionary hypotheses by comparing morphological data obtained in this study with the molecular phylogeny of Říčan et al (2022). Specifically, using body shape morphometrics in the context of a biogeographic reconstruction of molecular phylogeny, we test whether the upland and lowland fauna show consistent differences in body shape and proportion that could be explained as adaptations to local aquatic conditions along the elevational gradient of each main river basin (Kullander 1986, Říčan 2017).…”

“…), with high habitat complexity due to accumulated tree trunks, branches, etc. (Kullander 1986, Crampton 2011, Říčan 2017Figs. 1-2, Figs.…”