Crenicichla ploegi, a new species of pike-cichlid of the C. saxatilis group from the Rio Juruena and upper Rio Paraguai basins in Brazil, with an updated diagnosis and biogeographical comments on the group (Teleostei: Cichlidae)

Abstract

Crenicichla ploegi, new species, is described based on material from the Rio Juruena (Rio Papagaio, Rio do Sangue, Rio Arinos, and Rio Juruena itself) and from tributaries of the upper Rio Paraguai (upper Rio Jauru, upper Rio Cabaçal and upper Rio Sepotuba) in Mato Grosso, Brazil. Crenicichla ploegi is the twenty-third species of the C. saxatilis group. It is distinguished from all other species of the group by the presence of dark spots and vermiculations on snout, interorbital area and dorsally on head in adults vs. dark markings absent or present only in juveniles but absent in adults, and by the presence of a deep and strongly pigmented lateral band present in both juveniles and adults, occupying a depth of 4-6 horizontal scale rows vs. lateral band narrower, occupying a depth of 2-3 horizontal scale rows, and conspicuous only in juveniles and smaller specimens, faded or absent in larger specimens. Diagnostic characteristics of the C. saxatilis group proposed in previous studies were discussed to update the diagnosis of the group, and morphological comparisons among the species included in the group, with biogeographical comments, are provided. The presence of conspicuous dark markings dorsally on the head and the presence of a prominent midlateral band are hypothesized to be paedomorphic characteristics, retained from juvenile conditions in the context of the species of the C. saxatilis group.

Predation impacts brain allometry in female guppies (Poecilia reticulata)

“…The cichlids used were acquired through the aquarium trade and fed with live guppies prior to the experiment. Note that this is a sister species to C. frenata, the guppy's natural predator (Varella et al 2018). Control fish (16 individuals per tank) were held in two 11 L transparent tanks which were located at each side of the experimental tank.…”

Checklist and practical identification key for the cichlid fishes (Cichliformes: Cichlidae) of the La Plata drainage in Bolivia, including three new geographical records

“…Crenicichla ploegi and C. semicincta are similar and parapatric species. The form can be distinguished from C. lepidota by a higher scale count (58-71 E1 scales) and the colour pattern (Varella et al 2018). The latter differs from C. lepidota by lacking a ring of iridescent scales around the lateral spot and having this spot elongated and nearly integrated in the midlateral longitudinal band.…”

“…Menezes et al (2000) and Varella (2011) reported on additional undescribed species of Crenicichla , whose distribution, however, may be restricted to the headwaters of the río Paraguay in Brazil. In 2018, one species was formally described as Crenicichla ploegi Varella, Loeb, Lima & Kullander, 2018 (Varella et al 2018).…”

Updated distribution and morphological variation of the genus Pseudanos in the Río de la Plata basin (Characiformes: Anostomidae)

“…Based on our results, P. trimaculatus is added to the list of fish species shared between the Amazon and Río de la Plata regions. Carvalho & Albert (2011) 2021, Varella et al 2018) shared between the Amazon and Río de la Plata basins. In addition to P. trimaculatus, other anostomids, such as Abramites hypselonotus (Günther), Leporellus vittatus (Valenciennes), Leporinus friderici (Bloch), L. striatus Kner, and L. octomaculatus Britski and Garavello, have been previously reported to be conjointly present in those basins (Carvalho & Albert 2011, Garavello et al 1992.…”