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Introduction
In the last few years, several cases of malformations in batoids have been documented. In general, these malformations are related to embryonic development of endogenous origin (genetic or hormonal), pollution by chemical particles, and environmental anomalies caused by the degradation of the environment (Torres-Huerta et al., 2015; Ehemann & González-González, 2018; Capape et al., 2019).
Elasmobranchs with malformations such as ocular malformation in the round stingray Urobatis halleri (Rubio-Rodríguez et al., 2010), pelvic fin deformation in the longtail stingray Dasyatis longa (Escobar-Sánchez et al., 2009), and occurrence of a monoclasper in the banded guitarfish Zapteryx exasperata (Escobar-Sánchez et al., 2009) have been documented in the Gulf of California.
Guitarfishes of the genus Pseudobatos are abundant elasmobranch species captured by artisanal fishing in the Gulf of California (Bizzarro et al., 2007; Smith et al., 2009). These species represent a fishing resource of wide importance for local and national consumption. The spadenose guitarfish, Pseudobatos buthi Rutledge, 2019, was recently described from the coast of the Gulf of California. It is an aplacental viviparous (yolk sac viviparity, also called lecithotrophic viviparity) ray, where the embryos receive nutrients through the yolk sac (personal observation; Hamlett et al., 2005).
The present study reports for the first time a clasper malformation in Pseudobatos buthi captured in the Gulf of California. To elucidate the causes of the morphological abnormality, histological analysis was made to describe the reproductive system, and concentration levels of heavy elements (cadmium, copper, iron, manganese, silver, lead and zinc) were determined in muscle and liver.
Materials and methods
Two specimens of Pseudobatos buthi were collected, the first one on 16 August 2019 (specimen A) and the second one on 19 September 2019 (specimen B) at San Bruno fishing camp, Baja California Sur, Mexico, located in the western coast of the Gulf of California (Figure 1). The specimens were obtained from artisanal fishing of elasmobranchs and were caught with a 6-inch mesh-size gillnet. The total length, disc width, disc length, and the clasper length from base to tip (clasper internal length) of each specimen were measured (Table 1) (Last et al., 2016).
Fig. 1.
San Bruno fishing camp in the western coast of the Gulf of California, Mexico.
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