First Record of Bicephaly in the Brazilian Sharpnose Shark, Rhizoprionodon Lalandii

Abstract

Congenital deformities are relatively common in rays and sharks. The present study aimed to describe a case of bicephaly in an R. lalandii embryo. Through radiographic images and evaluation of the external and internal condition of the embryo in comparison with a young of the year with no deformities of the same species, it was possible to characterize the abnormality observed. Such data are important to determine the frequency and types of anomalies observed in elasmobranchs, thusallowing greater knowledge about developmental abnormalities in the group and their possible causes. RESUMODeformidades congênitas são relativamente comuns em raias e tubarões. O presente estudo teve como objetivo descrever um caso de bicefalia em um embrião de R. lalandii. Através de imagens radiográficas e avaliação da condição externa e interna do embrião em comparação com um jovem do ano sem deformidades da mesma espécie, foi possível caracterizar a anormalidadeobservada. Tais dados são importantes para determinar a frequência e tipos de anomalias observadas em elasmobrânquios, permitindo assim o maior conhecimento sobre as anormalidades de desenvolvimento no grupo e suas possíveis causas.Palavras-chave: Malformação; Tubarão; Espécie endêmica; Morfologia.

Morphological abnormalities in seven American round ray specimens: A review of America's batomorph anomalies

“…However, the aetiology of cojoined twinning is still uncertain (Sans‐Coma et al., 2017). Over 24 shark specimens with this anomaly have been recorded worldwide (Ehemann et al., 2016; Kanagusuku et al., 2020; Lamarca et al., 2017; Prado et al., 2020; Sans‐Coma et al., 2017), with Prionace glauca being the most frequent species. In contrast, at least three batomorph cases with this anomaly are available, two for Rhinoptera spp.…”

A mouthless late‐term coach whipray Himantura uarnak embryo (Elasmobranchii, Dasyatidae) has implications for our understanding of matrotrophy in chondrichthyans

“…Various teratological conditions have been reported in chondrichthyans, including bicephaly (Bornatowski & Abilhoa, 2009; Galván‐Magaña et al, 2011; Guida et al, 2013; Muñoz‐Osorio et al, 2013; Prado et al, 2020), cyclopia (Cabanillas‐Torpoco et al, 2023), anophthalmia (Ehemann et al, 2022; Rolim et al, 2020), albinism (Clark, 2002; Sandoval‐CaStillo et al, 2006), and assorted skeletal deformities (Bonfil, 1989; Moore, 2015; Wosnick et al, 2019; Zaera & Johnsen, 2011). Malfusion of the pectoral fins and head is one of the more commonly reported teratological conditions in the batoid elasmobranchs (Batoidea) (Ehemann et al, 2022), and the rostral malformation observed here is similar to occurrences in Rogers' round ray Urotrygon rogersi (Jordan & Starks 1895) (Mejía‐Falla et al, 2011) and Kuhl's maskray Neotrygon kuhlii (Müller & Henle 1841) (Ranjith et al, 2019).…”

Teratological records in blue shark Prionace glauca embryos from the South-western Atlantic Ocean

“…Within the last two decades, reports of abnormalities in elasmobranch embryos have increased worldwide, and a wide variety of abnormal morphological conditions have been described. The reports come from a range of seas and oceans, including the Atlantic Ocean (Clark, 2002; Coelho & Erzini, 2006; Mancini et al ., 2006; Delpiani et al ., 2011; Zaera & Johnsen, 2011; Wagner et al ., 2013; Dos Santos & Gadig, 2014; Afonso et al ., 2016; Lamarca et al ., 2017; Ramírez-Amaro et al ., 2019; Prado et al ., 2020), Pacific Ocean (Goto et al ., 1981; Clark, 2002; Bejarano-Álvarez et al ., 2011; Galván-Magaña et al ., 2011; Hevia-Hormazábal et al ., 2011; Bejarano-Álvarez & Galvãn-Magaña, 2013; Muñoz-Osorio, et al ., 2013; Escobar-Sanchez et al ., 2014; Becerril-García et al ., 2017; Pastén-Marambio et al ., 2018; Rodriguez-Romero et al ., 2019), Mediterranean Sea (Saidi et al ., 2006; Bottaro et al ., 2008; Sans-Coma et al ., 2016), Caribbean (Ehemann et al ., 2016) and Indian Ocean (Moore, 2015).…”