Historical Field Records Reveal Habitat as an Ecological Correlate of Locomotor Phenotypic Diversity in the Radiation of Neotropical Geophagini Fishes.

AbstractPhenotypic macroevolutionary studies provide insight into how ecological processes shape biodiversity. However, the complexity of phenotype-ecology relationships underscores the importance of also validating phenotype-based ecological inference with direct evidence of resource use. Unfortunately, macroevolutionary-scale ecological studies are often hindered by the challenges of acquiring taxonomically and spatially representative ecological data for large and widely distributed clades. The South American cichlid fish tribe Geophagini represents a continentally distributed radiation whose early locomotor morphological divergence suggests habitat as one ecological correlate of diversification, but an association between locomotor traits and habitat preference has not been corroborated. Field notes accumulated over decades of collecting across South America provide firsthand environmental records that can be mined for habitat data in support of macroevolutionary ecological research. In this study, we applied a newly developed method to transform descriptive field note information into quantitative habitat data and used it to assess habitat preference and its relationship to locomotor morphology in Geophagini. Field note-derived data shed light on geophagine habitat use patterns and reinforced habitat as an ecological correlate of locomotor morphological diversity. Our work emphasizes the rich data potential of museum collections, including often-overlooked material such as field notes, for evolutionary and ecological research.

Teleocichla wajapi, a new species of cichlid from the rio Jari, Brazil, with comments on T. centrarchus Kullander, 1988 (Teleostei: Cichlidae).

Teleocichla wajapi, new species, is described from the rio Jari basin, northern Brazil. The new species differs from its congeners by possessing four anal-fin spines, 56-62 scales in El series, smaller orbital diameter (24.6-30.2% of head length) and barred or zigzag color pattern on flanks. New information on the morphology and distribution of T. centrarchus is provided based on recently collected material.

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).

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.

Crenicichla chicha, a new species of pike cichlid (Teleostei: Cichlidae) from the rio Papagaio, upper rio Tapajós basin, Mato Grosso, Brazil

Crenicichla chicha, new species, occurs in clear, fast-running waters with rocky substrates in the rio Papagaio and tributaries. It is distinguished from all other Crenicichla species by the combination of two character states: infraorbitals 3 and 4 co-ossified (vs. separated) and 66-75 scales in the row immediately above to that containing the lower lateral line (E1 row scales). Crenicichla chicha shares a smooth preopercular margin, co-ossification of infraorbitals 3 and 4, and some color features with C. hemera from the adjacent rio Aripuanã drainage, rio Madeira basin. It differs from Crenicichla hemera in more E1 scales (66-75 vs. 58-65) and presence of a conspicuous black narrow stripe running from infraorbital 3 obliquely caudoventrad toward the preopercular margin vs. a rounded and faint suborbital marking present on infraorbitals 3-4. Examination of the type series and additional material from the rio Aripuanã confirms that Crenicichla guentheri Ploeg, 1991 is a junior subjective synonym of C. hemera Kullander, 1990.

Crenicichla chicha, espécie nova, ocorre em águas claras, correntes e com substrato rochoso, no rio Papagaio e tributários. É distinta de todas as outras espécies de Crenicichla pela combinação de dois estados de caracteres: ossos infraorbitais 3 e 4 co-ossificados (vs. separados) e 66-75 escamas na série imediatamente superior àquela que contém a linha lateral posterior (série E1). Crenicichla chicha compartilha o pré-opérculo liso, a co-ossificação dos infraorbitais 3-4 e aspectos do colorido com Crenicichla hemera do rio Aripuanã, bacia do rio Madeira. Difere de C. hemera por possuir mais escamas na série E1 (66-75 vs. 58-65) e uma listra suborbital preta e estreita, bem evidente, percorrendo obliquamente desde o infraorbital 3 até a margem do pré-opérculo vs. uma mancha suborbital arredondada e fraca situada nos infraorbitais 3-4. O exame da série típica e de material adicional proveniente do rio Aripuanã confirma que C. guentheri Ploeg, 1991 é um sinônimo júnior de C. hemera Kullander, 1990.