BARBELED HOUNDSHARK

This shark lives in brackish water, with a very unique placenta

The Barbeled houndshark (Leptocharias smithii) is a species of shark and the only member of the family Leptochariidae. It is found in the coastal waters of the eastern Atlantic Ocean from Mauritania to Angola, at depths of 32-246 feet in muddy habitats near river mouths. It has a very slender body, noticeable nasal barbels, and long furrows. It also has sexually dimorphic teeth. It also gives birth to live young.

 

Family: Leptochariidae – Barbel Houndsharks

Genus: Leptocharias 

Species: smithii

Taxonomy:

Phylum– Chordata

Class– Chondrichthyles

OrderCarcharhiniformes

Common NameGround Sharks

Family– Leptochariidae

Common NameBarbel Houndsharks

GenusLeptocharias

Speciessmithii

Status: IUCN Red List NEAR THREATENED

Average Size and Length: They are born greater than 20 cm/ 7.8 inches. Mature males have been measured between 55-60 cm/1.8-2 feet. Mature females have been measured between 52-58 cm/1.7-1.9 feet. The maximum recorded is 82 cm/2.6 feet.

Current Rare Mythical Sightings: The genus Leptocharias was coined by South African physician and zoologist Andrew Smith, without any associated species, in an 1838 Magazine of Natural History article by Johannes Müller and Friedrich Henle. Müller and Henle added a species a year later in their Systematische Beschreibung der Plagiostomen but adopted the name Triaenodon smithii because they regarded Leptocharias as a junior synonym of Triaenodon. Later authors recognized the validity of Leptocharias and rearranged it between the families Carcharhinidae and Triakidae before placing it in its own family. The type specimen is an adult male collected off Cabinda Province, Angola.

Teeth and Jaw: The mouth is long, angular and arched. It reaches past the anterior ends of the eyes. The labial furrows are long. The teeth are small and cuspidate. It has 46–60 upper tooth rows and 43–54 lower tooth rows. Each tooth is small, with a narrow central cusp and a pair of lateral cusplets.  The central cusp is pointed and straight but angled to the side. The males have greatly enlarged anterior teeth. Sexual dimorphism in the teeth.

Fossilized teeth belonging to an extinct relative, L. cretaceus, have been recovered from Late Cretaceous (Santonian and Campanian ages, 86–72 Ma) deposits in Britain. (Underwood, C.J. & D.J. Ward (2008). “Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous)” (PDF). Palaeontology. 51 (3): 509–536).

Head: Its eyes are cat-like, horizontal and oval. There are internal nictitating membranes. A pair of tiny spiracles is present behind the eyes. The nostrils have slender barbels.

Tail: The lower caudal fin lobe is virtually absent.

Demographic, Distribution, Habitat, Environment and Range: The Barbeled houndshark can be found in the eastern Atlantic from Mauritania to Angola (20°C – 27°C; 22°N – 23°S, 26°W – 17°E). They may also possibly be found to Morocco and the Mediterranean. They are found on the continental shelf near the bottom between 32-246 feet. They are quite common laying on the mud off of river mouths. It is considered tropical, brackish, demersal. It prefers temperatures of 68–81 °F, salinities of 35–36 ppt, and dissolved oxygen levels of 3–4 ppm.

Diet: They feed on crustaceans (crabs, lobsters and shrimps), small bony fish (like sardines, anchovies, snake eels, blennies, gobies, and flatfish), and skates. It is more than likely opportunistic. Its stomach contents have also contained flying fish eggs, octopus, sponges and items that are not edible (like feathers, vegetable scraps, and flowers).

Aesthetic Identification: The Barbeled houndshark is small and slender. It is light grey-brown in color. It is white ventrally. The two dorsal fins are small and about equal in size. The first dorsal fin is positioned between the pectoral and pelvic fins, and the second dorsal fin over the anal fin. The dorsal margin of the caudal fin is smooth and lacks a notch, or precaudal pit, at its base.

Biology and Reproduction: They are viviparous with a spherical placenta that is unique. Once the embryos exhaust their supply of yolk, they are nourished through a placental connection formed from the depleted yolk sac. The largest fetuses on record measured 20 cm/7.9 inches long, which is presumably close to the birth size.

A morphological study by Compagno in 1988 was inconclusive on the relationship of Leptocharias to other carcharhiniform families. Similarly, a molecular phylogenetic study by López et al. in 2006 found that, though Leptocharias certainly belonged to a derived clade also containing the families Hemigaleidae, Triakidae, Carcharhinidae and Sphyrnidae, its position within that group changed depending on the DNA sequence and type of analysis used. (López, J.A., J.A. Ryburn, O. Fedrigo and G.J.P. Naylor (2006). “Phylogeny of sharks of the family Triakidae (Carcharhiniformes) and its implications for the evolution of carcharhiniform placental viviparity” (PDF). Molecular Phylogenetics and Evolution. 40 (1): 50–60).

Known parasites include the copepods Eudactylina leptochariae and Thamnocephalus cerebrinoxius.

Behavioral Traits, Sensing and Intelligence: The males may use their greatly enlarged front teeth in courtship and copulation. Pregnant females occur off of Senegal between the months of July through October. Their gestation period is at least four months. They have seven pups per litter.

Speed: It is likely strong and active swimming. This is based on its strong musculature, long tail, short trunk, and small liver.

Barbeled Houndshark Future and Conservation: They are currently near threatened. They are taken by many fisheries as bycatch (by artisanal and commercial fisheries using hook-and-line, fixed-bottom gillnets, and bottom trawls) and utilized as meat and leather. The meat is sold smoked, fresh, dried or salted. Their habitat is extremely limited and restricted. Their status should be studied in much more detail.

Barbeled Houndshark Recorded Attacks on Humans: Not a threat to humans.