Common names
Zwerghai, Tiburón pigmeo, Tollo pigmeo, Squale pygmée, Pygmy shark

Short Description
Original Diagnosis after EBERT [22775]: Field Marks: Conical, moderately long, blunt, compressed snout, needle–like upper teeth and bladelike lowers, compressed body, gill slits increasing greatly in size from front to back, lobate, chimaera–like pectoral fins, midventral keel on caudal peduncle, no dorsal–fin spines, no anal fin, asymmetrical caudal fin, cloacal gland, dark colour with conspicuous light fin margins. Diagnostic Features: Anterior nasal flaps very short, not expanded into barbels; snout moderately long, compressed and conical, length about 2/5 of head length and less than distance from mouth to pectoral–fin origins; gill openings increasing in size from front to back, fifth over twice length of first; lips thick, fringed, but not suctorial; teeth strongly different in upper and lower jaws, uppers small, with narrow, acute, erect cusps and no cusplets, not bladelike, lowers much larger, bladelike, interlocked, with a high, broad, nearly erect cusp and distal blade, edges not serrated; tooth rows 29 upper jaw, 34 lower jaw. Both dorsal fins spineless; first dorsal–fin origin well behind free rear tips of pectoral fins, insertion about equidistant between pectoral and pelvic–fin bases and well ahead of pelvic–fin origins; second dorsal fin somewhat larger than first, base less than 1.5 times length of first dorsal–fin base; origin of second dorsal fin well ahead of pelvic–fin origins; pectoral fins with greatly expanded, broadly lobate free rear tips and inner margins, much as in chimaeras; caudal fin asymmetrical, not paddle–shaped, upper lobe long, lower lobe moderately long subterminal notch well–developed. No precaudal pits or lateral keels on caudal peduncle, but with a midventral keel. Dermal denticles flat and block–like, not pedicellate, no posterior cusps on flat, depressed crowns. Cloaca greatly expanded and modified as a luminous gland with secretory papillae. Vertebral counts and spiral valve turn counts not available. Colour: blackish brown with conspicuous light fin margins.

Distribution
Circumglobal: In subtropical to temperate waters. Southeast Atlantic: near Ascension Island, east of Fernando de Noronha Island, and west of Cape of Good Hope, South Africa. Indian Ocean: Madagascar to Western Australia. North Pacific: Midway Islands, Hawaiian Islands to off California, USA. South Pacific: between New Zealand, Phoenix Island and southern Chile. Source: www.gbif.org

Human uses
fisheries: of no interest

Biology
Ovoviviparous, with 8 young per litter. Size at birth between 6 and 10 cm [518]. Distinct pairing with embrace [17086].

Size / Weight / Age
22.0 cm TL (male/unsexed; [518]); 27 cm TL (female)

Habitat
bathypelagic; marine; depth range 0 - 1800 m [544]

Dentition
tooth formula (upper/lower): 9-11/10-11 [1131];

Links: SEM-images of teeth

Remarks
shark-references Species-ID=2252;

Parasites (arranged by Jürgen Pollerspöck)
Cestoda

• Heterosphyriocephalus tergestinus (Pintner, 1913) [16112] [25091]