Ontogenetic studies of the eggs and larvae of fish can provide information on the initial life history and biology of a species, are important for taxonomic and evolutionary studies, and for cultivation in captivity. The aim of this study was to analyze and describe the main morphological differences in the larval ontogeny of Pseudoplatystoma reticulatum, Leiarius marmoratus, and its hybrid (♀ P. reticulatum × ♂ L. marmoratus), as well as to identify characteristics that can identify the species and their hybrid at the larvae and juvenile stages. 205 L. marmoratus, 210 P. reticulatum, and 205 hybrid specimens were analyzed, all of which were obtained through induced reproduction. Analyses were performed from hatching to 30 days post‐hatching. 19 morphometric and 5 meristic characteristics were evaluated, in addition to chromatophore shape and distribution. The specimens were classified into two life periods: Larval (stages: yolk sac, pre‐flexion, flexion, and post‐flexion) and Juvenile. Newly hatched larvae were transparent, poorly developed, and had a scarcity of chromatophores. During the early stages of larval development, the three groups showed similarities in appearance and proportional dimensions. However, at both the end of the post‐flexion stage and at the juvenile period when individuals were approximately 2 cm long, it was possible to differentiate between hybrids and their parental species by their morphometric, meristic, and pigment characteristics. The hybrid, despite occupying an intermediate position in relationship to its parents, exhibited a shape and size more similar to P. reticulatum, its maternal parent.

中文翻译：

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网状假platystoma（Eigenmann＆Eigenmann 1889）和黑斑Learius marmoratus（Gill，1870）的孵化后个体发育比较

鱼卵和幼虫的个体发育研究可以提供有关物种的初始生命史和生物学的信息，对于分类学和进化研究以及人工饲养都具有重要意义。这项研究的目的是分析和描述网纹假单胞菌，Learius marmoratus及其杂种（♀P . reticulatum  ×♂L . marmoratus）的幼虫个体发育的主要形态学差异，并确定可以鉴定幼体和幼体阶段的物种及其杂种。205 L. marmoratus，210 P.reticulatum，分析了205个杂种标本，所有这些标本都是通过诱导繁殖获得的。从孵化到孵化后30天进行分析。除了色谱体的形状和分布，还评估了19个形态学特征和5个综合特征。标本分为两个生命周期：幼虫（卵黄囊，屈曲前，屈曲和屈曲后）和幼年期。新孵化的幼虫是透明的，发育较差，并且缺乏色谱团。在幼虫发育的早期阶段，这三组动物在外观和比例尺寸上表现出相似性。但是，在屈曲后阶段的末尾和幼体长约2 cm的幼年期，可以通过形态，亲缘关系和色素特征来区分杂种及其亲本。尽管杂种在与其亲本的关系中处于中间位置，但其形状和大小与其母本P. reticulatum更相似。