Geometric morphometric analysis of cyclical body shape changes in color pattern variants of Cichla temensis Humboldt, 1821 (Perciformes: Cichlidae) demonstrates reproductive energy allocation

Abstract

Previously recognized color and pattern variants of adult Cichla temensis in Amazon flood pulse river environments reflect the cycling of individuals through seasonal sexual maturity and spawning. Individuals also vary in shape from blocky to fusiform. To determine if shape differences are related to patterns of fat reserve deposition and utilization, and to quantify the relationship of shape with color and pattern variation and life history status, specimens in each of four previously defined grades of color and pattern variation were compared using geometric morphometric techniques. Progressive shape changes occurred between grades independent of sex and correlated to gonosomatic index (GSI). Thin plate spline deformation visualizations indicate that the observed shape differences are related to fat deposition patterns. The seasonal timing of shape change and its link to color pattern variation, sexual maturity and local water level conditions suggests a relationship between the physiological and behavioral characteristics of C. temensis and the cyclical flood pulse pattern of its habitat.As variantes de cor e padrão previamente reconhecidos dos adultos de Cichla temensis em ambientes alagáveis amazônicos refletem o ciclo de indivíduos durante o período de maturidade sexual e desova. Indivíduos também variam na forma de oblonga a fusiforme. Para determinar se as diferenças de forma estão relacionadas aos padrões de deposição e utilização das reservas de gordura e quantificar a relação da forma com cor, variação de padrão e status da história de vida, espécimes de cada quatro níveis de cor e variação de padrão previamente definidos foram comparados usando técnicas de morfometria geométrica. Mudanças progressivas ocorreram na forma entre os níveis independentes do sexo e correlacionadas ao índice gonadossomático (IGS). Visualizações de finas deformações na placa da espinha indicam que as diferentes formas observadas estão relacionadas aos padrões de deposição de gordura. O período de mudança de forma e sua ligação com a variação do padrão de cor, maturidade sexual e as condições do nível da água local sugerem uma relação entre as características fisiológicas e comportamentais de Cichla temensis e o padrão de inundação cíclico do seu habitat.

Morphological variation among populations of Hemigrammus coeruleus (Characiformes: Characidae) in a Negro River tributary, Brazilian Amazon

“…However, within populations there can be variation due to sexual maturity (Reiss, Grothues, 2015) and sexual dimorphism (Gomes-Jr., Monteiro, 2008). Thus, we investigated morphological divergence related to sexual dimorphism prior to assessing population divergence.…”

“…heterorhabdus (García-Alzate et al, 2010), Aspidoras albater Nijssen, Isbrücker 1976 (Secutti et al, 2011), Cichla kelberi Kullander, Ferreira 2006(Berbel-Filho et al, 2013, Astyanax bimaculatus (Linnaeus 1758) (Santos, Araújo, 2015) and Brycon henni Eigenmann 1913 and Saccodon dariensis (Meek, Hildebrand 1913) (Restrepo-Escobar et al, 2016a;2016b). Regarding solely Amazonian fishes, even fewer studies have examined morphological variation in body shape and size, e.g., CoxFernandes (1998) on two apteronotid species, Sidlauskas et al (2011) on Leporinus cylindriformis group and Reiss, Grothues (2015) on Cichla temensis.…”

Stock structure analysis of the Arabian red shrimp (Aristeus alcockiRamadan, 1938) in the Indian coast with truss network morphometrics

“…In many previous studies, it has been found that differences in sex are likely to contribute to shape differences affecting total variance in morphometric distances (Sajina et al 2011;Reiss and Grothues 2015;Pazhayamadom et al 2015). In the present analysis, both males and females were included to accommodate the effect of sex on their morphometry.…”

Morphometric Assessment of Golden Mahseer Populations in the Ganga River Basin, India

“…The Truss networks measure across-body distances, connecting two landmarks to cover the entire fish, theoretically generating more differentiating morphometric characters with greater discriminating power. However, trusses with serial linear measurements have limitations in the multivariate analysis of shape (Reiss and Grothues 2015). Thus, geometric morphometrics, which is a landmark-based technique, is currently considered the most rigorous morphometric technique.…”