Living naked: first case of lack of skin‐related structures in an elasmobranch, the blackmouth catshark (Galeus melastomus)

Abstract

As far as is known, in this paper the first case of lacking of skin-related structures (epidermis, stratum laxum, dermal denticles and teeth) in a free-swimming elasmobranch, the blackmouth catshark, Galeus melastomus, is reported. The individual was caught by trawl in Sardinian waters (central-western Mediterranean) in July 2019 at a depth of 500 m. Although this kind of morphological abnormality is potentially fatal, the observations suggested that the specimen was in good health and well developed.

Rampant tooth loss across 200 million years of frog evolution

“…Based on our review of the literature, only seven other extant vertebrate lineages are entirely edentulous. There are no described edentulous chondrichthyan species (but see Mulas et al (2020) for the first described aberrant case in a catshark). To our knowledge, teeth have been entirely lost only twice in living actinopterygian fishes in the Syngnathidae (seahorses and pipefish; Lin et al 2016) and the milkfish, Chanos chanos (Kohno et al 1996, Wang et al 2017).…”

Primeiro registro de eversão vaginal em Psammobatis rutrum Jordan, 1891 (Rajiformes: Arhynchobatidae)

“…: Sandoval-Castillo, Mariano-Melendez & Villavicencio-Garayzar, 2006;Bottaro, Ferrando, Gallus, Girosi & Vacchi, 2008;Jones, Hoffmayer & Gropp, 2016;Quigley, Carlos, Barros-Garcia & MacGbahann, 2018;Lara-Mendoza & Guerra-Jiménez, 2020), morfológicas (Ex. : El Kamel-Moutalibi, Mnasri, Boumaïza, Reynaud & Capapé, 2011Pastén-Marambio, Hevia-Hormazábal, Acuña & Vega, 2018;Marouani, Jarray, Karaa & Jarboui, 2019;Ranjith, et al, 2019;Mulas et al, 2020;Rolim, Rotundo, Stabile & Vaske-Júnior, 2020) e reprodutivas (Oddone & Amorim, 2008;Ribeiro-Prado, Oddone, Amorim & Capapé, 2009;Capapé, El Kamel-Moutalibi, Mnasri, Boumaïza & Reynaud, 2012;Costa, Borges & Capapé, 2013 & Capapé, 2017;Zhao, Chen, Jiang, Yang, & Xiao, 2017;Ehemann & González-González, 2018;Burgos, Gonzalez, Falla, & Escalon, 2019;Capapé, Kassar, Reynaud, & Hemida, 2019;Sen, Dash, Valappil, Kizhakudan, & Chakraborty, 2020;Silva & Silva-Casas, 2020). Grande parte das anomalias relacionadas aos órgãos reprodutivos está relacionada a intersexualização, deformidades ou ausência de cláspers.…”

First record of partial albinism in the critically endangered Angelshark (Squatina squatina) (Linnaeus, 1758)

“…Genetic alterations can also cause more severe conditions, such as the case in which the blackmouth catshark (Galeus melastomus) presented an absence of various skin-related structures (Mulas et al, 2020).…”

“…In the case of chondrichthyans (sharks, rays and chimaeras), this alteration is not documented for all species, but there are several cases where leucism or albinism has been confirmed, including zebra shark ( Stegostoma faciatum ), smooth dogfish ( Mustelus schimitti ), finetooth shark ( Carcharhinus isodon ), kitefin shark ( Dalatias licha ), blacktip shark ( Carcharhinus limbatus ), Aleutian skate ( Bathyraja aleutica ), swell shark ( Cephaloscyllium ventriosum ), Lucifer's dogfish ( Etmopterus lucifer ), spotted ratfish ( Hydrolagus colliei ), and the smooth butterfly ray ( Gymnura micrura ) (Arronte et al ., 2022; Becerril‐García et al ., 2017). Genetic alterations can also cause more severe conditions, such as the case in which the blackmouth catshark ( Galeus melastomus ) presented an absence of various skin‐related structures (Mulas et al ., 2020).…”