Rhinoptera brasiliensis Müller, 1836

Jones, Christian M., Driggers Iii, William B., Hannan, Kristin M., Hoffmayer, Eric R., Jones, Lisa M. & Raredon, Sandra J., 2020, An annotated checklist of the chondrichthyan fishes inhabiting the northern Gulf of Mexico Part 1: Batoidea, Zootaxa 4803 (2), pp. 281-315 : 301-302

Rhinoptera brasiliensis Müller, 1836 —Brazilian cownose ray, ticon cownose ray

Synonyms: None

Distribution. This species is distributed throughout the northern GOM, from the Texas/ Mexico border to southern Florida, although it appears to be more prevalent in the northwestern than the northeastern GOM. Although little is known of its habits in the northern GOM, being easily and historically confused with Rhinoptera bonasus (see above), it has been captured in near shore shallow waters out to waters 32 m in depth.

First Record in GOM. The first record of this species in the northern GOM was reported by Naylor et al. (2012). However, due to a lack of representative Rhinoptera brasiliensis DNA in their database, and the close genetic relatedness between Rhinoptera brasiliensis and Rhinoptera steindachneri Evermann and Jenkins, 1901 ( Jones et al. 2017), those authors identified anomalous individuals from the northern GOM that were divergent from Rhinoptera bonasus as Rhinoptera c.f. steindachneri , as Rhinoptera steindachneri was the closest matching species represented in their dataset. Jones et al. (2017) verified the second species as Rhinoptera brasiliensis .

Remarks. As stated above, recent studies ( Naylor et al. 2012, Jones et al. 2017) have indicated the presence of this species in the northern GOM. This species is morphologically very similar to Rhinoptera bonasus and the two species are therefore difficult to differentiate without detailed examination and/or genetic verification. It is likely, based upon historic reports ( Bigelow and Schroeder 1953, Acero and Garzon 1982, Isaís and Dominguez 1996), that Rhinoptera brasiliensis has been present in the northern GOM for several decades, if not longer. It has been suggest- ed (e.g. Fricke et al. 2019) that Raja brasiliensis Müller and Henle, 1841 is a synonym of Rhinoptera brasiliensis . However, Müller and Henle (1841) clearly describe Raja brasiliensis as a rajiform skate, claiming that it “could be a variation of Raja undulata ” (Müller and Henle 1841, our translation). As the only specimen of Raja brasiliensis was destroyed during World War II ( Fricke et al. 2019), its exact identity may never be known. It is clear, however, from the description that Raja brasiliensis is not conspecific with Rhinoptera brasiliensis . The name Rhinoptera jussieui ( Cuvier, 1829) has been used by many authors (e.g. Gunther 1870, Garman 1913) as synonymous with Rhinoptera brasiliensis . However, Cuvier’s (1829) use of the name (as Raja jussieui ) is in reference to a specimen (jaws) illustrated by Jussieu (1721) which the later author describes as originating from China. This may mean that Rhinoptera jussieui is the valid name for Rhinoptera javanica Müller and Henle, 1841 , but certainly precludes it from being accepted as synonymous with Rhinoptera brasiliensis as that species is restricted to the western Atlantic Ocean.

Conservation Status. Endangered, although this status will likely change as their known range has been greatly expanded to include waters where they are less exposed to exploitation.