First record of albinism in the swell shark, Cephaloscyllium ventriosum (Elasmobranchii: Carcharhiniformes: Scyliorhinidae)

Abstract

Abstract. We report the first record of albinism in the swell shark, Cephaloscyllium ventriosum (Garman, 1880). The specimen was caught off the southern part of the Baja California Peninsula, Mexico. The shark had no skin pigmentation and golden-coloured eyes. The pigmentation of its eyes may be related to the previously reported presence of ocular pigments that are different from melanin, and thus not affected by albinism.

First record of albinism in the lanternshark family, Etmopteridae

“…The lack of pigmentation is derived from a deficiency of melanin production, affecting part (incomplete, imperfect and partial albinism, including leucism; Becerril‐García et al ., 2017; Moura et al ., 2015) or the entirety (complete or total albinism; Bigman et al ., 2016) of an organism. Albinism in chondrichthyans is considered rare, although cases have been reported in a growing diversity of chondrichthyan fishes (see Bigman et al ., 2016, for a review), with recent records published on the southern stingray Dasyatis americana (Hildebrand & Schroeder, 1928) (Wakida‐Kusunoki, 2015), the dwarf round stingray Urotrygon nana (Miyake & McEachran, 1988) (Tolentino et al ., 2016) and the swell shark Cephaloscyllium ventriosum (Garman, 1880) (Becerril‐García et al ., 2017); the latter two are considered novel records for the family Urotrygonidae and genus Cephaloscyllium. Reports of deep‐sea specimens are sparse and have included the kitefin shark Dalatias licha (Bonnaterre, 1788) (Bottaro et al ., 2008), the shovelnose dogfish Deania calcea (Lowe, 1839) (Moura et al ., 2015) and the spotted ratfish Hydrolagus colliei (Lay & Bennett, 1839) (Reum et al ., 2008).…”

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

“…Skin colour aberrations, as well as reproductive system abnormalities, usually represent less severe conditions and are recorded to a greater extent among adult, free‐swimming individuals (Moore, 2015). Particularly, skin colour aberrations include albinism, defined as the total lack of pigmentation in both the skin and iris ( e.g ., Ball et al ., 2013; Becerril‐García et al ., 2017; Bigman et al ., 2016; Bottaro et al ., 2008; Clark, 2002; Quigley et al ., 2018); leucism, a particular form of albinism ( e.g ., Bigman et al ., 2016; Quigley et al ., 2018; Veena et al ., 2011) and irregular coloration (Gervais et al ., 2016). Although these types of aberrations could lead to higher mortality rates, especially for species that depend on colouration or pattern to survive, the observation of fully grown albino and leucistic individuals proves that colour changes do not always lead to a reduction in survivorship (Ball et al ., 2013; Bigman et al ., 2016).…”

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

“…Several North, Central, and South American countries have reported chondrichthyan fauna catalogued as megadiverse, ranging between 99 and 219 species (e.g., Calle‐Morán & Béarez, 2020; Cornejo et al., 2015; Ehemann et al., 2018; Ehemann et al., 2019; Espinoza et al., 2018; Mejía‐Falla & Navia, 2019; Rosa & Gadig, 2014). In addition, published records of different morphological abnormalities in several elasmobranch species collected near the American continent are frequently mentioned (e.g., Becerril‐García et al., 2017; Bejarano‐Álvarez & Galván‐Magaña, 2013; Bonfil, 1989; Dos Santos & Gadig, 2014; Ehemann et al., 2016; Escobar‐Sánchez et al., 2014; Lamarca et al., 2017; Lopes et al., 2020), apparently being more documented in shark rather than in rays and skates species. However, the number of specimens, of the commonly called “batoids,” published so far with any abnormal conditions from this continent is unknown.…”

“…In general, the most documented morphological abnormalities in American cartilaginous fishes are related to albinism (e.g., Anislado‐Tolentino et al., 2016; Becerril‐García et al., 2017; Escobar‐Sánchez et al., 2014; Jones et al., 2016), incomplete fins fusion (e.g., Hauser‐Davis et al., 2020; Mejía‐Falla et al., 2011; Rolim et al., 2020; Torres‐Huerta et al., 2015) and bicephaly (e.g., Ehemann et al., 2016; Galván‐Magaña et al., 2011; Sans‐Coma et al., 2017). The causes of such anomalies remain uncertain; however, most authors agree to hypothesize an effect of nutrition issues, genetic disorders, embryo development and water pollution as the main probable causes (e.g., Becerril‐García et al., 2017; Hauser‐Davis et al., 2020; Sans‐Coma et al., 2017; Torres‐Huerta et al., 2015).…”

“…In general, the most documented morphological abnormalities in American cartilaginous fishes are related to albinism (e.g., Anislado‐Tolentino et al., 2016; Becerril‐García et al., 2017; Escobar‐Sánchez et al., 2014; Jones et al., 2016), incomplete fins fusion (e.g., Hauser‐Davis et al., 2020; Mejía‐Falla et al., 2011; Rolim et al., 2020; Torres‐Huerta et al., 2015) and bicephaly (e.g., Ehemann et al., 2016; Galván‐Magaña et al., 2011; Sans‐Coma et al., 2017). The causes of such anomalies remain uncertain; however, most authors agree to hypothesize an effect of nutrition issues, genetic disorders, embryo development and water pollution as the main probable causes (e.g., Becerril‐García et al., 2017; Hauser‐Davis et al., 2020; Sans‐Coma et al., 2017; Torres‐Huerta et al., 2015). The present work aimed to document several morphological abnormalities observed directly on free‐living specimens of Haller's round ray Urobatis halleri (Cooper, 1863), the spotted round ray Urobatis maculatus Garman, 1913, the smalleyed round stingray Urotrygon microphthalmum Delsman, 1941, the blotched stingray Urotrygon chilensis (Günther, 1872) and the thorny stingray Urotrygon rogersi (Jordan & Starks, 1895), all of which are endemic species of the American continent belonging to the Urotrygonidae family.…”