Ontogenetic development of Heterocharax macrolepisEigenmann (Ostariophysi: Characiformes: Characidae) with comments on the form of the yolk sac in the Heterocharacinae

Abstract

Fishes in early developmental stages frequently have morphological features that differ from those of adult stages, and many characters found later in ontogeny are not available in initial stages. Hence, morphological descriptions of early stages are useful to provide information for the identification of eggs and larvae, a knowledge still restricted among Neotropical fishes. We studied the development of Heterocharax macrolepis, a heterocharacine whose adult specimens from the aquarium trade were kept and spawned at around 23-24ºC. A developmental series of 51 specimens was preserved, ranging from 3.2 mm notochord length to 18.6 mm standard length, covering approximately the first 73 days post-hatching. We described the development of main morphological features emphasizing those useful in the identification of H. macrolepis larvae (i.e., appearance of preopercle spine and development of the pseudotympanum). We also compared H. macrolepis with photographs taken of live larval specimens of Gnathocharax steindachneri, recently included in the Heterocharacinae. Both species have a yolk sac with a small rounded projection directed posteroventrally. Although this information is not yet available for all pertinent taxa, the different yolk sac shape in other representatives of the Characiformes may indicate that this peculiar yolk sac represents an additional synapomorphy of the Heterocharacini.Peixes em estágios iniciais de desenvolvimento frequentemente apresentam características morfológicas distintas dos adultos e muitos caracteres presentes em estágios avançados não são disponíveis em estágios iniciais. Assim, descrições morfológicas dos estágios iniciais de desenvolvimento de peixes são úteis por fornecerem subsídios para a identificação de ovos e larvas, um conhecimento ainda escasso entre peixes Neotropicais. Estudamos o desenvolvimento de Heterocharax macrolepis, espécie de Heterocharacinae cujos exemplares adultos provenientes do aquarismo foram mantidos e reproduzidos entre 23-24ºC. Uma série de desenvolvimento de 51 exemplares foi preservada, medindo entre 3,2 mm de comprimento da notocorda e 18,6 mm de comprimento padrão, incluindo os primeiros 73 dias pós-eclosão. Descreveram-se detalhadamente os principais aspectos morfológicos, enfatizando características úteis na identificação de larvas de H. macrolepis (i.e., surgimento do espinho do pré-opérculo, desenvolvimento do pseudotímpano). Comparamos H. macrolepis com fotografias de larvas vivas de Gnathocharax steindachneri, recentemente incluída em Heterocharacinae. Ambas espécies possuem saco vitelínico com pequena projeção arredondada póstero-ventral. Ainda que a informação não esteja disponível para os táxons pertinentes, o distinto formato do saco vitelínico em outras linhagens de Characiformes pode indicar que esta forma do saco vitelínico peculiar represente sinapomorfia adicional de Heterocharacini.

Comparative development in Moenkhausia pittieri and Paracheirodon innesi (Ostariophysi: Characiformes) with comments on heterochrony and miniaturization in the Characidae

“…The development of the characiform type is characterized by adipose fin outgrowth after the complete reduction of the larval fin fold at a late stage in ontogeny, when the other median fins (anal and dorsal) are already developed (Bender & Moritz, ). This is observed in Heterocharax macrolepis Eigenmann 1912 (Mattox et al, ), M. pittieri and P. innesi (Figs and ). Since the formation of the adipose fin occurs considerably later in characiform ontogeny, its absence in some of the smaller members of Characidae may be a consequence of truncation in development associated with heterochronic processes during the evolution of small body sizes.…”

“…The latter review found that 87 of 213 miniature species (40·8%) are Characiformes, of which 67 (77%) are members of the family Characidae. Despite the striking number of miniature characids, there are few studies of the ontogeny of such small fishes (Mattox et al, ).…”

Early ontogeny of yellowtail tetra fish Astyanax lacustris (Characiformes: Characidae)

“…Kendall, Ahlstrom, and Moser (1984) report that each species has a distinct pigmentation pattern, the size, and location of the melanophores being genetically determined. For characids, the pigmentation pattern is very similar, with the initial larvae being less pigmented than the more developed ones (Anjos & Anjos, 2006; Çelik et al., 2012; Galuch et al., 2003; Montoya, Arias, & Oliveira‐Angel, 2010; Nakatani et al., 2001; Park et al., 2014; Walter, 2012; Mattox, Hoffmann, & Hoffmann, 2014; Santos et al, 2017; Ferreira‐Marinho, 2017). However, at the end of the larval period (postflexion), A. lacustris larvae have conspicuous spots, both in the humeral region and in the caudal peduncle, similar to those found in adults, becoming an important character in the identification of individuals during their initial development.…”

“…Studies of small species are still poorly known (Anjos & Anjos, 2006; Çelik, Celik, Cirik, Gurkan, & Hayretdag, 2012; Ferreira‐Marinho, 2017; Galuch, Suiberto, Nakatani, Bialetzki, & Baumgartner, 2003; Mattox, Hoffmann, & Hoffmann, 2014; Park et al., 2014; Santos et al, 2017; Walter, 2012). However, it is an important tool for a better understanding of biology (Nakatani et al., 2001) and systematic and/or phylogenetic position of species (Assega, Birindelli, Bialetzki, & Shibatta, 2016; Ferreira Marinho, 2017; Mattox et al, 2014), as well as for studies of identification and evaluation of fishing resources (Nakatani et al., 2001) and in aquaculture production systems (Bialetzki, Garcia, & Orsi, 2016; Martinez & Bolker, 2003).…”

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

“…The ontological development in fish describes changes involved during their formation, from fertilization to their adult form (reproductive maturation), covering the whole period of biological cycle that includes eggs, embryos, larvae and juvenile period (Nakatani et al, ). The ontogenetic study of eggs and larvae in fish provides important information about the knowledge of initial life history and biology of the species, being an important tool for larviculture, besides providing subsidy for evolutionary studies (taxonomy and systematic) (Godinho, Santos, & Sato, ; Jomori & Jose, ; Mattox, Hoffmann, & Hoffmann, ; Ziober, Reynalte‐Tataje, & Zaniboni‐Filho, ).…”