Characterization of the initial ontogeny ofLeiarius marmoratus(GILL, 1870): larvae to juvenile

Abstract

Summary Aiming to provide data on the biology of Leiarius marmoratus, which will aid in its production in captivity, as well as in studies for its preservation in the environment, this work had as objectives: analyze and describe main morphological alterations during larval ontogeny of the species. We analyzed 205 individuals, obtained by induced reproduction (Colpani Pisciculture) and kept in CEPTA/ICMBIO, Pirassununga, São Paulo, Brazil. Analyses were performed from hatching moment to 30th day. The specimens were classified into two periods: larval (Stages: vitelline, pre‐flexion, flexion, post‐flexion) and juvenile. Hatched larvae showed ident chromatophores only at anterior and posterior extremities of yolk sac. The standard length ranged from 2.16 mm (yolk) to 28.84 mm (Youth). Dorsal fin rays were initially observed at flexion stage (12–14 rays). Major alterations occurred during post‐flexion/juvenile stage, when dorsal, pectoral, pelvic, anal, and caudal fins were observed and pigmentation intensified throughout the lateral region, forming bands in the body, one between the end of the head and beginning of dorsal to pelvic fin, and another one beginning at dorsal to caudal peduncle and four longitudinal at the head.

Comparative post‐hatching ontogeny of Pseudoplatystoma reticulatum (Eigenmann & Eigenmann 1889) and Leiarius marmoratus (Gill, 1870) and their hybrid

“…In relation to the studied species, it is possible, despite overlapping, to be a strong aid in the differentiation between the two species and their hybrid: P. reticulatum (45–49 myomeres), L. marmoratus (49–56 myomeres), and hybrid (48–56 myomeres). Meristic characters, such as myomere count, have been described for L. marmoratus (Coelho et al., 2019) and P. reticulatum (Andrade et al., 2016). This is an important variable in the identification of fish larvae (Snyder, 1979).…”

“…In order to understand the changes that occur during ontogeny, more information is needed on growth patterns and morphometric and morphological characteristics, together with meristic, structural, and pigmentary characteristics. Verifying and categorizing the emergence of specific anatomical characteristics, as well as cataloguing inter‐ and intra‐species variations, will help to develop clear species identification methods (Bialetzki et al., 2001; Coelho et al., 2019). The identification of hybrid species can be quite complex, and there are common contradictions, as the gene mixture may contain different proportions of the parent gene pools, resulting in morphological characteristics that may resemble any of the parental species (Porto‐Foresti et al., 2013; Trigo et al., 2008).…”

Spawning induction and embryonic development of Salminus hilarii (Characiformes: Characidae)

“…Previous studies have been carried out with S. hilarii especially focused on reproduction (Honji et al, 2009(Honji et al, , 2013, larval rearing (Araújo et al, 2012), and population genetics (Silva et al, 2015) and providing essential information about this species production. Embryonic and larval studies are essential to understand fish development, mainly those performed with commercial interests or endangered species, not only to generate knowledge about their development characteristics, but also to have a comparison model to know when normal development is altered by external factors (Coelho et al, 2019). According to Morrison et al (2001) knowledge about embryonic development in fish is essential to define adequate strategies to avoid high mortality rates influenced mainly by embryo deformities and bad formations.…”