page_title: Oval electric ray
section_title: Description
hierarchical_section_title: Oval electric ray / Description
caption_attribution_description: English: Ventral view of Typhlonarke tarakea (misidentified as T. aysoni in original work)
context_page_description: The oval electric ray is a little-known species of sleeper ray in the family Narkidae. It is endemic to New Zealand, where it is generally found on the sea floor at a depth of 300–400 m. Seldom exceeding 30 cm in length, this species has a thick, oval pectoral fin disc and a short, stout tail with a single dorsal fin. It is blind, as its tiny eyes are covered by skin. Its pelvic fins are divided in two, with the anterior portion forming a limb-like appendage. These appendages likely allow the ray, which may not be able to swim at all, to "walk" along the bottom. The claspers of adult males extend beyond the disc. Polychaete worms are known to be part of its diet, and its reproduction is aplacental viviparous. It can produce an electric shock for defense. The International Union for Conservation of Nature presently lacks the data to assess its conservation status.
context_section_description: The pectoral fin disc of the oval electric ray is ovoid in shape, tapering smoothly towards the rear, and has a very thick margin. The eyes are minute and located 2–3 mm (0.079–0.118 in) beneath the surface of the skin; though not visible externally, their positions are marked by small white patches. The spiracles follow the eyes and are oval with smooth rims. The nostrils are closely together, with their outer rims curled to nearly form tubes and their inner rims expanded and fused together into a fleshy skirt-shaped curtain, that nearly conceals the small, deeply recessed mouth. The teeth number 11 rows in either jaw and are arranged with a quincunx pattern to form narrow plates restricted to the front of the jaws. The teeth in the back have a single sharp cusp, while those at the front are worn down and blunt. There are five pairs of short, curved gill slits, with the first and fifth pairs smaller than the others.
  Each pelvic fin is divided: the anterior portion is formed into a long appendage resembling a finger, while the posterior portion is merged smoothly with the pectoral fin to form part of the disc. The trailing margins of the pelvic fins join the body evenly, without a notch. Adult males have cylindrical claspers that extend past the disc margin. The single dorsal fin has a rounded margin and originates just ahead of where the disc margin meets the body. The tail is short and thick, with faint lateral skin folds running along the sides, and ends in a nearly circular caudal fin. The skin is completely smooth. The oval electric ray is dark brown above, lightening towards the disc margins and on the underside. The area around the mouth and nostrils, and the underside of the pelvic appendages, are white. This species can grow to 36 cm (14 in) long, but most do not exceed 30 cm (12 in).
caption: The oval electric ray differs in disc shape from the related T. aysoni.
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