The Longnose Pygmy shark (Heteroscymnoides marleyi) is a rare species of Dogfish shark in the family Dalatiidae (Kitefin sharks). It is known only from a handful of specimens collected from the cold oceanic waters of the Southern Hemisphere, between the surface and a depth of 1,647 feet. Reaching 15 inches in length, it is a minuscule shark.
Family: Carcharhinidae- Kitefin sharks
Common Name– Dogfish Sharks
Common Name– Kitefin Sharks
Status: IUCN Red List LEAST CONCERN
Average Size and Length: The largest known specimen of the Longnose Pygmy shark is a male 15 inches long. They are born at around 12 cm. The mature female specimen was 13 inches.
Teeth and Jaw: The mouth of the Longnose Pygmy shark is transverse and surrounded by thin, smooth lips. The upper teeth have 22 rows and are small and upright with a single narrow cusp. The lower teeth number 23 rows and are much larger, broader, and knife-like, and interlock to form a continuous cutting surface.
Head: The snout of the Longnose Pygmy shark is long and bulbous. It comprises about half the head length, and comes to a blunt, conical tip. The eyes are large, lack nictitating membranes and are followed by large spiracles. The nostrils are long and angled, with a very short flap of skin on their anterior rims.
Denticles: The small dermal denticles have sharp wedge-shaped crowns with median ridges, and are placed on stems.
Tail: The caudal fin of the Longnose Pygmy shark is broad, with a well-developed lower lobe and a deep ventral notch near the tip of the upper lobe. It is symmetrical and paddle-shaped.
Demographic, Distribution, Habitat, Environment and Range: The Longnose Pygmy shark has been caught in the western Indian Ocean off eastern KwaZulu-Natal, in the southeastern Atlantic Ocean near the Walvis Ridge, and in the southwestern Pacific Ocean off Chile. Based on these records, it may have circumglobal distribution in the Southern Hemisphere, epipelagic, inhabiting subantarctic waters and cold ocean currents, including the Benguela and the Humboldt. They can be found in the open ocean between the surface and a depth of 1,647 feet, in water that is between 2,720–13,120 feet deep.
Diet: The Longnose Pigmy shark more than likely feeds of fish and invertebrates.
Aesthetic Identification: The body of the Longnose Pygmy shark is slender and moderately compressed from side to side; a dwarf shark. The five pairs of gill slits are tiny and of uniform width. It is dark brown, with dark or blackish, then light bands at the fin margins. The two dorsal fins lack spines. The first dorsal originates over the pectoral fin bases; the second dorsal is slightly larger than the first but is about equal in base length, and originates over the middle of the pelvic fin bases. The pectoral fins are short and somewhat paddle-like. There is no anal fin. The underside is covered by minute bioluminescent photophores possibly for use in counter illumination.
Biology and Reproduction: More than likely, the Longnose Pygmy shark is ovoviviparous. Males and females attain sexual maturity at under 14 and 13 inches long.
Behavioral Traits, Sensing and Intelligence: Unknown.
Longnose Pygmy Shark Recorded Attacks on Humans: Not a threat to humans.