Gymnuridae, Fowler, 1934

Elasmobranch, Its Implications For Global, Parasitology, Diversity And, Naylor, G. J. P., Sc, Caira, J. N., Ct, Jensen, K., Ks, Rosana, K. A. M., Fl, White, W. T., Csiro, Tas, Last, P. R., Csiro & Tas, 2012, A Dna Sequence-Based Approach To The Identification Of Shark And Ray Species And Its Implications For Global Elasmobranch Diversity And Parasitology, Bulletin of the American Museum of Natural History 2012 (367), pp. 1-262 : 85-86

Gymnuridae (butterfly rays)

Gymnura species

The analysis included a total of 50 specimens of Gymnura . This was among the most problematic genera with respect to specific identifications of specimens. We have treated these specimens as representing nine distinct species. The haplotype map for phenotype ( fig. 102A) supports this level of diversity, in that there are no overlapping haplotypes among the specimens of any of these nine species. The haplotype map for geography ( fig. 102B) provides support for the notion that two species of Gymnura ( G. crebripunctata and G. marmorata ) cooccur in the Gulf of California, two species cooccur in the Indo- Pacific ( G. zonura and G. cf. poecilura 1), and that potentially three species cooccur in northern Australia ( G. australis , G. micrura , and Gymnura sp. 1 ). Furthermore, our analyses are consistent with the suggestion that butterfly rays in the Persian Gulf are distinct from those in the other localities sampled here. However, clearly this genus would benefit greatly from additional taxonomic work.

Gymnura cf. poecilura complex ( fig. 64)

The analysis, which included 17 specimens showing a resemblance to Gymnura poecilura , yielded two clusters. Given that no specimens from India, the type locality of this species, were included, we have given the clusters numerical designations. One, designated Gymnura cf. poecilura 1, contained 12 specimens collected from throughout Borneo ; two of these specimens were vouchered (GN3641 5 IPPS BO430 and GN4507 5 CAS 229034 . The range of pairwise differences among specimens in this cluster was 0–13, with an average of 5.3. The second cluster, designated Gymnura cf. poecilura 2, consisted of the other five specimens, all of which were collected from the Gulf of Oman. Specimens comprising the latter cluster had a range of pairwise differences of 1–8, with an average of 4.8. The average of the pairwise differences between specimens the two clusters was 120.5. It is likely that at least one of these forms is an undescribed species.

Gymnura zonura (zonetail butterfly ray) ( fig. 64)

Seven specimens identified as this species were included in the analysis. These came from Borneo, Singapore, and the Philippines and thus represent eastern elements of the Indo-West Pacific distribution of this species.The Philippine specimen (GN4369 5 BRU 105) was treated by Compagno et al. (2005b) as Aetoplatea zonura . These specimens were generally consistent with G. zonura ; however, they varied in dorsal color pattern from the typical patterned form of G. zonura (GN4838) to plain (GN4830). The analysis yielded a single cluster comprised of these specimens. The range in pairwise differences among specimens in this cluster was 1–14, with an average of 6; the upper end of this range was accounted for by a specimen from the Philippines. Specimens in this cluster grouped among other Gymnura species , supporting the placement of this species in Gymnura (see White et al., 2006; Last et al., 2010c) rather than in the separate genus Aetoplatea . It is closest to Gymnura sp. 1 ; the average of the pairwise differences between specimens of G. zonura and Gymnura sp. 1 was 129.2; between those of G. cf. poecilura 1 was 159.5, and between those of G. cf. poecilura 2 was 143.6.

Gymnura sp. 1 ( fig. 64)

The analysis included three specimens from the western North Atlantic that had preliminarily been identified as Gymnura altavela , but that grouped well outside specimens identified as G. altavela from the eastern Atlantic. Given that the type locality of G. altavela is in the eastern Atlantic, specimens comprising that cluster (see below) have been provisionally identified as G. altavela , and those comprising the genetically divergent western Atlantic cluster, as Gymnura sp. 1 . Unfortunately, images of material from the western Atlantic are not available. In the interim, these have been identified as Gymnura sp. 1 , but it should be recognized that they may refer to a Gymnura species not represented in this analysis. These specimens differed from one another by 0–1 bases. They clustered along with G. zonura . The average of the pairwise differences between Gymnura sp. 1 and those of G. zonura is 129.2, between Gymnura sp. 1 and G. cf. poecilura 1 150.3, and between the G. cf. poecilura 2 cluster 141.3.

Gymnura australis (Australian butterfly ray) ( fig. 64)

A single specimen of this, the only species of its genus reported from Australia, was included in the analysis. This specimen was collected from the Arafura Sea off northern Australia. It represents a northwestern element of the distribution of this species. It clustered most closely with G. zonura and Gymnura sp. 1 , with average pairwise differences of 158.4 and 131.3, respectively.

Gymnura crebripunctata (longsnout butterfly ray)

( fig. 64)

In total, seven specimens of this species were included in the analysis. These comprised a single cluster, and exhibited a range of pairwise differences of 1–10, with an average of 5. These specimens, which were collected in the Gulf of California, are representative of the northern portion of the distribution of this species, which is known to occur coastally as far south as Panama.

Gymnura marmorata (California butterfly ray)

( fig. 64)

The four specimens of this species included here comprised a single cluster and exhibited a range of pairwise differences of 1–3, and an average of pairwise differences of 1.5. These specimens, collected in the Gulf of California, are representative of the northern elements of the distribution of this species, which has been reported as far south as Peru. The average of the pairwise differences between specimens of this species, and those of their sympatric congener, G. crebripunctata , was 180.3. This is consistent with the work of Smith et al. (2009) in supporting the recognition of G. marmorata as a taxon distinct from G. crebripunctata .

Gymnura micrura (smooth butterfly ray) ( fig. 64)

One specimen identified as this species, collected from the western Atlantic, was included in the analysis. Unfortunately, images of this specimen are not available, and thus the identity of this specimen has not been confirmed. However, field notes (K. Cleason, personal commun.) indicate that this specimen lacked a tail spine. This specimen clustered most closely with the specimens of G. marmorata , but the average of the pairwise differences between specimens of these two species was 160.8. This specimen represents only a portion of the western Atlantic distribution of this species, which occurs throughout much of the central western and eastern seaboards of the Atlantic Ocean.

Gymnura altavela (spiny butterfly ray) ( fig. 64)

Ten specimens that are generally morphologically consistent with this species were included in the analysis. All 10 specimens came from Senegal and thus represent only a small portion of the distribution of this species, which has been reported from throughout much of the central western and eastern seaboards of the Atlantic Ocean. The range of pairwise differences among these specimens was 0–5, with an average of 1.9 bases. Specimens in this cluster and those of their sympatric congener Gymnura sp. 1 had an average pairwise difference of 196.5.