Ecomorphology of the digestive tract of the brazilian electric ray Narcine brasiliensis (Olfers, 1831) (Torpediniformes: Narcinidae)

Abstract

Marinsek, G.P., Viliod, M.C.L. and Mari, R.B. 2017. Ecomorphology of the digestive tract of the brazilian electric ray Narcine brasiliensis (Olfers, 1831) (Torpediniformes: Narcinidae). -Acta Zoologica (Stockholm) 98:229-236.Elasmobranchii shows particular characteristics that make them susceptible to the impacts caused by fishing pressure, especially bottom trawling, which mostly affect rays, as they have demersal habits. Based on food availability and feeding ability, Polychaeta and Sipunculiforme are the bases of Brazilian electric ray Narcine brasiliensis diet. Morphologically, the digestion starts in the oesophagus with acid mucines action. The existence of acid and neutral mucines in the posterior intestine prevents lesions in the mucosa and favours the passage of faeces and shell residues. Thus, this study shows the interaction between their habitat, the organisms and their morphophysiology.

Revision of Eocene electric rays (Torpediniformes, Batomorphii) from the Bolca Konservat-Lagerstätte, Italy, reveals the first fossil embryoin situin marine batoids and provides new insights into the origin of trophic novelties in coral reef fishes

“…This position is exactly comparable to that occupied by the gut-intestine tract in living electric rays (Fig. 15E), and in narcinids in particular (see Marinsek et al . 2017, fig.…”

Zeros as a result in diet studies, is this really bad? Rhinoptera steindachneri as a case study

“…Based on this and considering that R. steindachneri is a pelagic species with relatively high energetic demands to sustain metabolism, we could assume that it is a species that feeds frequently and could maintain a continual secretion of stomach acids, leading to very low pH levels even when fasting (Cortés et al ., 2008; Leigh et al ., 2017). Additionally, J-shaped relatively simple stomach anatomies such as that presented by R. steindachneri are associated with lower food retention, compared with more complex U-shaped stomach anatomies (Kobelkowsky, 2010; Marinsek et al ., 2017). The degree of grinding and crushing that prey tissues are submitted to accelerate digestion and facilitates the passage of stomach contents to the spiral valve to continue with the process of degradation and absorption.…”