Desenvolvimento inicial de larvas de Rhaphiodon vulpinus Agassiz (Characiformes, Cynodontidae)

Abstract

ABSTRACT. Initial development of Rhaphiodon vulpinus Agassiz larvae (Characiformes, Cynodontidae). The cynodontid fish Rhaphiodon vulpinus Agassiz, 1829, known as " peixe-cachorro", is lhe only species of the family occurring in the Pantanal of Mato Grosso. The initial development of its larvae was characterized, based on malerial collected with a 500 IJ m mesh size plankton-net, in several biotopes of the Pantanal of Barao de Melga~o, Slale of Mato Grosso, Central Brazil. The analysis was carried out with 72 larvae with slandard length (SL) between 4.7 and 13.8 mm. The morphometric measurements varied positively with standard length, and body proportions ranged 8.1-17.8% for head length (ffi.), 6.2-10.1% for body height, and 63.6-73.5%, 16.8-21.6%, and 61.8-78.2% SL, respectively for pre-dorsal, pre-pectoral and pre-anal distances. The eye diameter varied positively with HL and its proportion varied between 9.1 -22.5% HL. The body relations did not show great variation along the larval development. The morphological characterization of larvae from 4.7 to 5.8 mm SL, in the pre-flexion phase, showed the presence of an embryonic finfold covering the unrayed fins, exposed branchial arches , absence of exogenous digestive content, unpigmented eyes and round shaped head. Larvae with SL between 8. 1 and 13 .8 mm SL were in the flexion phase, presenting a pointed head, mouth filled with external and internal rows of numerous teelh, presence of exogenous food, pigmented eyes, branchial filaments still exposed, evident swimmi ng-bladder, and formation of the first caudal, dorsal and anal fins ' rays. Only individ uals in the pre-flexion and flexion phases were analyzed, and no completely developed fin was evidenced. A maximum number of 69 myomeres was counted and no evident pigmentation over the body observed. Comparing R.vulpinus larvae to those of other Characiformes, it was observed that this species and Apareiodo/l affillis Steindachner, 1879 present smaller body proportions , and variation range of body height , while R. vLlipiliLiS is characteri zed by a shorter eye diameter. The myomere number is a relevant feature for the identification of R. vuipiliLiS larvae, since it is the Characiform that possesses the highest myomere number, among those species of this family studied so far. KEY WORDS. Cynodontidae, Rlzaplziodoli vulpinus, larval development, ontogeny, morphomelrics o estudo da ecologia das fases iniciais do cicIo vital e da ontogeni a em peixes esta historicamente associ ado a biologia pesqueira e ao recrutamento de espec ies marinhas, principal mente daquelas de importancia comercial, sen do consideravel 0 volume de informa~6es sobre especies de agua salgada (BLAXTER 1984). Uma sinopse hist6rica e levantamento bibliografico podem ser encontrados em MOSER et at.

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

“…Among these species, C. pauciradiatus, P. megalostictus, and H. macrolepis were already classified in the same subfamily based on the long anal fin (e.g., Géry, 1977), a feature that might be related to the early shift of the onset of the anal-fin development. The difference on the onset of development between anal and dorsal fins reported herein is quite subtle, as both fins begin to develop at almost the same time (i.e., among cleared and stained specimens, rays of both fins are present simultaneously at 8.2 mm SL), similar to what was described for Rhaphiodon vulpinus (Sousa & Severi, 2002). These authors stated that due to the almost simultaneous onset of development of the dorsal and anal fins, this character might not have a significant taxonomic value.…”

“…In the context of the great diversity of fishes in the Neotropical region, knowledge of larval fishes from South and Central America is still insipient (Sousa & Severi, 2002) and generally restricted to sparse information in the literature (Ponton & Mérigoux, 2001). There are two landmarks in the study of Neotropical larval fishes: an important contribution focusing on the eggs and larval fishes of taxa mainly from the Paraná basin (Nakatani et al, 2001) which gathers information on all lineages of teleosts sampled in their study, and the comprehensive study of larval fishes in French Guyana carried out by Ponton & Mérigoux (2001).…”

“…These include studies on clupeiforms (e.g., Severi & Verani, 2006;Silva et al, 2010), siluriforms (e.g., Chacon, 1975;Godinho et al, 1978;Oldani, 1983a;Kossowski & Madrid, 1991;Cardoso et al, 1995;Sanches et al, 1999;Luz et al, 2001;Godinho et al, 2003;Lundberg et al, 2004;Feiden et al, 2005;Marques et al, 2008;Oliveira et al, 2008;Amorim et al, 2009;Faustino et al, 2010;Perini et al, 2010;Rodrigues-Galdino et al, 2010;Buzollo et al, 2011;Fuller, 2012;Honji et al, 2012;Nogueira et al, 2012;Weber et al, 2012), gymnotiforms (e.g., Kirschbaum & Schugardt, 2002) and perciforms (e.g., Prokes et al, 1987;Pena et al, 1988;Nakatani et al, 1997;Korzelecka-Orkisz et al, 2012), besides the Characiformes. More specifically within the latter order, most studies have focused on representatives of the Anostomidae (Godinho et al, 2003), Curimatidae (Araújo Lima, 1991;Perini et al, 2013), Cynodontidae (Sousa & Severi, 2002), Erythrinidae (Matkovic & Pisanó, 1989;Gomes et al, 2007;Bialetzki et al, 2008;Maciel et al, 2009;Gomes et al, 2010), Lebiasinidae (Taguti et al, 2009), Par...…”

Morphological development of Anchoviella vaillanti (Steindachner, 1908) (Clupeiformes: Engraulidae) larvae and early juveniles

“…In Brazil, important contributions have been made by Araújo-Lima (1985, 1991, Araújo-Lima et al (1993) and Oliveira et al (2008) for the Amazon region; Cavicchioli et al (1997), Nakatani et al (1997), Bialetzki et al (1998Bialetzki et al ( , 2001Bialetzki et al ( , 2008 and Sanches et al (1999Sanches et al ( , 2001 for the upper Paraná River; Sousa & Severi (2002) and Severi & Verani (2006) for the Paraguay River; and Godinho et al (2003) and Sampaio (2006) for the São Francisco River. These studies are mostly on Characiformes and Siluriformes and there is limited knowledge on the remaining 23 orders occurring in the Neotropics (Reis et al, 2003), including the 35 known clupeiform species distributed among Clupeidae, Engraulidae and Pristigasteridae.…”

Desenvolvimento embrionário, larval e juvenil de Hemisorubim platyrhynchos (Siluriformes, Pimelodidae) da bacia do rio Paraná

“…Descrições do desenvolvimento embrionário e/ou larval foram feitas para espécies de peixes de diferentes bacias hidrográficas brasileiras (nascimento & araújo-lima, 1993;nakatani et al, 1997caviccHioli et al, 1997;Bialetzki et al, 1998Bialetzki et al, , 2008sancHes et al, 1999;reynaltetataje et al, 2001;luz et al, 2001;sousa & severi, 2002;reynalte-tataje et al, 2004;maciel et al, 2009;oliveira et al, 2012;Honji et al, 2012). Hemisorubim platyrhynchos (Valenciennes, 1840), popularmente conhecida como jurupoca, é uma espécie de médio porte, pertencente à família Pimelodidae e tem ocorrência nos grandes rios da América do Sul, nas bacias dos rios Amazonas, Maroni, Orinoco e Paraná (reis et al, 2003).…”