Otolith atlas of fish of the Sinos River

Abstract

Otoliths are calcium carbonate structures located in the inner ear of fish; they are responsible for hearing and balance. The inner ear has three pairs of otoliths: the lapilli, the sagittae and the asterisci. The sagittae otoliths are the largest and their format is species-specific. Because of their composition, otoliths can resist to the digestive tract of ichthyophagous species, and they can be used as an important tool for identifying species of fish found in stomach contents. The purpose of this work is to provide a photographic guide of the sagittae otoliths of the main fish species from the Sinos River. This atlas consists of photographs of the sagittae otoliths of 36 species belonging to 15 families distributed in five orders.Keywords: photographic guide, sagittae, identification. Atlas de otólitos de peixes do Rio dos Sinos ResumoOtólitos são estruturas formadas por cristais de carbonato de cálcio, localizadas no labirinto do ouvido interno dos peixes. São responsáveis pela audição e pelo equilíbrio. O ouvido interno possui três pares de otólitos, os lapilli, os sagittae e os asterisci. Os denominados sagittae são os maiores e seu formato é espécie-específico. Devido a sua composição os otólitos conseguem resistir ao trato digestivo das espécies ictiófagas, dessa maneira podem ser empregados como uma importante ferramenta para a identificação de espécies de peixes em trabalhos com conteúdos estomacais. O objetivo deste trabalho é a disponibilização de uma referência visual dos otólitos sagittae das principais espécies de peixes do Rio dos Sinos, para que possam servir de base para trabalhos com conteúdos estomacais de espécies ictiófagas. Este atlas é composto de fotografias dos otólitos sagittae de 36 espécies de 15 famílias distribuídas em cinco ordens.Palavras chave: guia fotográfico, sagittae, identificação.

The developmental variations of the sagitta otolith in the young and mature male of a hermaphrodite polynemidae fish, Eleutheronema tetradactylum (Shaw, 1804)

“…The medial surface of the sagitta comprises a well-developed sulcus groove as also reported in other fishes (Dehghani et al, 2016;Omar & Moselhy, 2016;Abdulsamad, 2017;Jawad et al, 2018;Khedher & Fatnassi, 2018), and this groove may assist for connecting the medial surface with the sensory cells of the internal ears (Popper & Hoxter, 1981;Popper & Lu, 2000). A number of sulcus morphologies of E. tetradactylum are characteristically identical with another marine as well as freshwater Perciformes fishes (Smale et al, 1995;Bremm & Schulz, 2014;Omar & AMohamed, 2016;Omar & Moselhy, 2016;Abdulsamad, 2017;Jawad et al, 2018;Bardhan et al, 2021). Hunt (1992) stated that the otolith morphologies between male and female fishes are almost the same, whereas several authors reported that there are some structural differences between these genders in many fish species (Vallisneri et al, 2008;Bostanci et al, 2012;Kontaş & Bostanci, 2015).…”

Hidden or unnoticed? Multiple lines of evidence support the recognition of a new species of Pseudocorynopoma (Characidae: Corynopomini)

“…Bushmann et al ., 2002 (MCP 18470, MCP 18471, MCP 18472 from laguna dos Patos drainage; describes the absence of gill gland). Bremm & Schulz, 2014 (Figure 9: sagitta otolith). Thomaz et al ., 2015, in part (MCP 21286, UFRGS 12389, from laguna dos Patos drainage; molecular phylogeny).…”

Otolith morphometry provides length and weight predictions and insights about capture sites of Prochilodus lineatus (Characiformes: Prochilodontidae)

“…Currently the use of otoliths in freshwater studies have increased (Silva, Stewart 2006;Lopez Cazorla, Sidorkewicj, 2011;Lozano et al, 2014). For example, one otolith atlas of Brazilian freshwater fish with relevant information was recently published (Breem, Schulz, 2014). Never theless, age and growth studies of freshwater fish using otoliths are still in the process of consolidation and far from stage of similar studies for marine species.…”