Hortle's whipray

The Hortle's whipray (Pateobatis hortlei) is a stingray from the family Dasyatidae that lives in the shallow, brackish estuaries and muddy tidal flats off southern New Guinea. Not much is known about this species.

Taxonomy

It gets its name from Kent Hortle, a biological consultant who gave scientists the first photographs and fresh specimens of the ray. The species was formally described in 2006 in the journal Zootaxa, based on an adult male 71 cm (28 in) across caught in the Minajerwi River estuary. This ray is part of the 'uarnacoides' species complex, which also includes H. chaophraya, H. granulata, H. lobistoma, H. pastinacoides, and H. uarnacoides.

Distribution and habitat

The ray’s range is limited to southern Papua province, and possibly neighboring Papua New Guinea. It stays in water no deeper than 10 m (33 ft), preferring brackish estuaries and intertidal mud flats.

Description

Its pectoral fin disc is heart-shaped and slightly longer than wide, with concave front edges that meet at a long, narrow, pointed snout. The eyes are tiny and set far apart, with large, teardrop-shaped spiracles right behind them. Between the nostrils is a broad, roughly rectangular flap of skin with a finely fringed rear edge. The mouth is strongly curved like a bow and lacks papillae.

The small, blunt teeth are arranged in a quincunx pattern and are stained orange to brown in adults, with 21–25 rows in the upper jaw and 24–28 in the lower. The five pairs of gill slits are distinctively S-shaped. The pelvic fins are short and broad.

The tail is very thin, 2.6 to 3.4 times as long as the body, and has no fin folds. One or two stinging tail spines sit on the upper surface about one-third of a disc width from the tail base. A wide band of flattened dermal denticles—including larger heart-shaped ones and smaller, irregularly shaped interstitial ones—runs along the back from in front of the eyes to the tail.

Small, sharp denticles are scattered over the snout, concentrated at the tip. The tail past the sting is fully covered with denticles. The lateral line system is well-developed on both the upper and lower surfaces. Smaller rays are plain greenish gray above, while larger ones are yellowish brown; the tail is uniformly brown and lighter in front of the sting.