Rhinobatos whitei Last, Corrigan et Naylor, 2014

Rhinobatos whitei Last, Corrigan et Naylor, 2014

IUCN standard name :: Philippine Guitarfish Fig. 10 View Figure 10 , Table 2 View Table 2

Material examined.

UPVMI 3127, 234 mm DW, 702 mm TL, male, fish landing site, Roxas, City, Capiz Province, Philippines, trawl, September 2021, coll. M. Batay. UPVMI 3128, 43 mm DW, 136 mm TL, juvenile, same data as preceding.

Morphological description.

Body moderately elongated and medium-sized, covered with tiny dermal denticles; trunk depressed and flattened. Disc broad and wedge-shaped. Head large and depressed. Eyes large, oval and protruding; spiracles very large, located just behind eye. Snout relatively long; tip bluntly pointed; anterior margin concave; rostral cartilages well separated and converging towards front area. Mouth moderately wide and slightly arched. Nostrils large, elongated, oval rather than rounded; nasal flap very small, narrow, not covering nostrils. Teeth very small, rhomboid, very compact; upper jaw with 83 rows; lower jaw with 77 rows. Dorsal fins falcate, almost equal in size, posterior margin straight. Pectoral fins flat and very large. Pelvic fin short, angular and firm, originating just behind free rear tip of pectoral fins (in juvenile specimen, free rear tip of pectoral fins not reaching insertion of pelvic fins); apex bluntly rounded. Caudal fin moderately large, asymmetrical; lower caudal-fin lobe absent. Gill slits five on each side; fifth slit obviously smallest.

Color of fresh specimen. Adult specimen ( UPVMI 3127): Body with dark-brown spots; underside white; dorsal fins with black free rear tip. Juvenile ( UPVMI 3128): Body dorsal surface brown with numerous small, white and brown-black spots; underside white; dorsal fins with black free rear tip; pectoral- and pelvic-fin edges creamy white.

Color of preserved specimen. Adult: Body brown with numerous tiny pale white to gray spots, and large brown to light brown spots (spots more pronounced than in fresh specimen); dorsal and caudal fins with white free rear tip. Juvenile: Body light brown with numerous tiny white and brown spots; dorsal fins with black free rear tip.

Distribution.

Philippines ( Last et al. 2014; Manjaji-Matsumoto 2017; this study).

DNA barcode.

COI sequences of 617 bp were submitted to GenBank under accession numbers OR 614481 ( UPVMI 3127) and OR 614470 ( UPVMI 3128).

Conservation status.

Critically Endangered

Remarks.

Rhinobatos whitei was originally described based on specimens collected from the markets in central and southern Philippines (specifically in Bacolod, Cebu, Dipolog, and Dumaguete), with a size range of 317–844 mm TL ( Last et al. 2014). Subsequent records have identified this species from Panay Island, Philippines ( Manjaji-Matsumoto 2017; this study), and to date, there have been no reports of its occurrence in other countries, affirming its status as a Philippine endemic. Rhinobatos whitei has been assessed as critically endangered due to severe declines in ray populations throughout the Philippines, coupled with the highly restricted geographic range of the species ( Dulvy et al. 2021). This study reports the first collection of a juvenile specimen, and knowledge on juveniles may be important in protecting the species.

Rhinobatos whitei and Rhinobatos manai White, Last et Naylor, 2016 share the characteristic of having whitish spots, which distinguishes them from other congeners ( White et al. 2016). However, the collected specimen was identified as R. whitei based on its poorly defined white spots and presence of large, diffuse dusky and orange blotches as described by Last et al. (2014). In contrast, R. manai is characterized by well-defined rusty brown spots and faint white spots with grayish edges, as described by White et al. (2016). Although no COI data are available for either species, the identification of the collected specimen was confirmed based on the morphological descriptions and coloration comparisons provided above.