Description of the initial development and temporal distribution of Microphilypnus tapajosensis larvae and juveniles in a reservoir in the Eastern Amazon

Abstract

Este estudo descreve o desenvolvimento inicial de larvas e juvenis de Microphilypnus tapajosensis usando dados merísticos, morfológicos e morfométricos e verifica sua distribuição temporal em um reservatório na Amazônia Oriental, analisando a hipótese de que esse ambiente seja ideal para o desenvolvimento e crescimento da espécie. As larvas e juvenis de M. tapajosensisapresentaram características comuns do grupo Eleotridae, com comprimento padrão variando de 3,0 mm a 8,9 mm, presença de cromatóforos dendríticos distribuídos na região ventral próxima à barbatana caudal e 28 miômeros totais. Durante o desenvolvimento inicial das larvas, a morfologia é o personagem que melhor diferencia M. tapajosensis de seus congêneres, seguido pelo número de raios das barbatanas peitorais em indivíduos jovens. A ocorrência de espécimes nos estágios larval e juvenil durante o período de amostragem indica que M. tapajosensispossui atividade reprodutiva ininterrupta, demonstrando-se como uma espécie oportunista. Finalmente, a presença de indivíduos ao longo de todos os meses, em todas as etapas larvais e juvenis, sustenta a hipótese de que o reservatório possui condições para o crescimento e desenvolvimento de M. tapajosensi s, indicando que esse ambiente é propício à manutenção e renovação de espécies.

Early development of the Neotropical fish known as long sardine Triportheus auritus (Valenciennes 1850) (Characiformes, Triportheidae)

“…T. auritus larvae in the preflexion stages are pelagic and transparent (Cajado et al., 2020), to pigmentation in that period represents an adaptive camouflage strategy in the water column and avoids attracting attention from visual predators (Sanches et al., 2001; Silva et al., 2021). While in the final stages of development, most of these individuals are colonizing water macrophyte stands (Oliveira, Suzuki, et al., 2020; Oliveira, Cajado, et al., 2020). In this way, intense pigmentation acts as camouflage while using structured environments (Machado‐Allison et al., 2020; Santos et al., 2017).…”

“…In addition to the pigmentation pattern, the total or partial number of myomeres is a relevant data for the identification of some fish groups in the larval phase (Oliveira, Suzuki, et al., 2020; Oliveira, Cajado, et al., 2020; Santos et al., 2020), mainly during the early stages of preflexion and flexion. T. auritus can be easily distinguished from other congeners sympatric in the Lower Amazon for having a greater number of myomeres (45–48) that differ from T. angulatus (34–38), T. pictus (36–38), T. rotundatus (39–40) e T. albus (39–40) (Table 3).…”

Early ontogeny of the commercially valuable fish red‐bellied pacu Piaractus brachypomus (Characiformes, Serrasalmidae) from the Amazon, Brazil

“…Among the main functional organs, the first to be formed in P. brachypomus are the eyes, nostrils, swim bladder and mouth, which appear along the yolk‐sac and pre‐flexion stages. This is associated with the need for the formation of sensory and locomotor structures, which occur simultaneously in the search for adequate exogenous foods (Aruho et al ., 2019; Oliveira et al ., 2020; Silva et al ., 2021).…”

Early development ofProchilodus nigricansSpix & Agassiz 1829 (Characiformes: Prochilodontidae) in captivity

“…After hatching, the individuals were categorized according to the flexion of the final section of the notochord and the development sequence of the fins and their supporting elements, in (I) larval period comprising four stages: (a) yolk sac, (b) preflexion, (c) flexion and (d) postflexion; and (II) juvenile period (Ahlstrom et al, 1976; modified by Nakatani et al, 2001). These classifications are widely adopted in several morphological characterization studies of the early stages of life of freshwater fish (Cajado et al, 2021; Lima et al, 2021; Oliveira et al, 2020; Oliveira et al, 2021; Santos et al, 2020; Silva et al, 2021).…”