Ontogenetic allometries and shape changes in the suckermouth armoured catfish Ancistruscf.triradiatus Eigenmann (Loricariidae, Siluriformes), related to suckermouth attachment and yolk‐sac size

Abstract

Ontogenetic allometries and shape changes in the suckermouth armoured catfish Ancistrus cf. triradiatus Eigenmann (Loricariidae, Siluriformes), related to suckermouth attachment and yolk-sac sizeEarly life-history stages of the loricariid catfish Ancistrus cf. triradiatus are described, from prehatch embryos to juveniles. The descriptions, as well as metric characters, indicate that the freeswimming embryonic stage is followed directly by the juvenile stage, without a true larval stage or metamorphosis. Intense, but gradual ontogenetic head-shape changes are present during the embryonic and free-living embryonic stages: the suckermouth gradually shifts from an almost rostral to a ventral position. The external and internal transformations related to this shape change are considered an adaptation to both the loricariid algae-scraping feeding mode and the need of suckermouth functioning from the moment of hatching, when a ventrally situated suckermouth would be disadvantageous, as a large yolk sac is present.

Application of the physical habitat simulation for fish species to assess environmental flows in an Atlantic Forest Stream in South-eastern Brazil

“…On the other hand, G. brasiliensis had an ample adaptive plasticity that enables this species to occur in a wide variety of mesohabitat types (Sabino & Castro, 1990;Meschiatti, 1995;Aguiaro & Caramaschi, 1998;Agostinho & Júlio Jr., 1999;Vono & Barbosa, 2001) including large boulders and boulders that ensure high habitat structuration (i.e., deep-slow areas typical of the upper reach and the upper part of the lower reach), as well as at the proximity of sandy banks with organic matter such as twigs and leaf litter (i.e., the shallow-fast areas of the lower part of the lower reach). Furthermore, A. multispinis was closely associated to the bottom, favored by its flatted body and ventral funnel-like sucking mouth to adhere to boulders and large boulders (Geerinckx et al, 2008). Such characteristics enable this species to explore a particular niche dimension of both reaches.…”

“…For example B. ornaticeps has fusiform body, forked caudal fin that confer good swimming ability to explore the water column (Castro et al, 2010). Ancistrus multispinis has a flatted body, a ventrally placed suckermouth and the ability to use the fins to move and adhere to hard substrate, a hydrodynamic advantage that reduces current drag when the fish is positioned against substrate in fastflowing (Geerinckx et al, 2008). Geophagus brasiliensis is characterized by a compressed and deep body, pectoral fins in lateral position that confer great maneuver capacity and vertical movements, allowing to explore both lotic and lentic systems (Oyakawa et al, 2006).…”

“…Ancistrus multispinis (Regan, 1912) is a mediumsized catfish of the Loricariidae family that reaches up to 14.2 cm of total length (Fisch-Muller, 2003). This species has a specialized buccal apparatus that helps to adhere to hard substratum (rocky, stones and logs) (Geerinckx et al, 2008), dwelling small rivers and streams (Oyakawa et al, 2006) and having herbivore habits (Assis et al, 2009). Geophagus brasiliensis (Quoy & Gaimard, 1824) is a medium-sized Perciformes of the Family Cichlidae reaching up to 22.5 cm of total length (Costa et al, 2015).…”

Redescription of the endangered hypoptopomatine catfish Parotocinclus spilurus (Fowler, 1941) (Siluriformes: Loricariidae) from the upper rio Jaguaribe basin, northeastern Brazil

“…3). Ontogenetic shape changes were already observed in loricariids, including hypoptopomatine catfishes (Aquino & Miquelarena, 2001;Rosa et al, 2014) and must be related to allometric development of bones, muscles and plates structures (Geerinckx et al, 2008(Geerinckx et al, , 2009.…”

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“…Allometric growth model is a commonly used method in analysis of relative growth in early larval period (Osse and van den Boogaart 2004;Peña and Dumas 2009). Larval development stages of teleostei were characterized by using high grade allometric growth models (Van Snik et al, 1997;Geerinckx et al, 2008). These models can be used by characterization of normal growth models in rearing and aquaculture management (Peña and Dumas 2009).…”