Cape Town - Marking Shark Awareness Day on Wednesday, scientists are hailing the discovery of a new shark and two rays in African waters.
A new species of shark and two rays - guitarfish/ flatsharks to be exact - have recently been described by Dr David Ebert, an ichthyologist devoted to the study of fish based in California USA, consulting to the WILDOCEANS’ Shark and Ray Protection Project.
Ebert is also a research associate at the South African Institute for Aquatic Biodiversity (SAIAB).
The new shark, the lanternshark (Etmopterus brosei), commonly called the Barrie’s lanternshark, resembles other species of the Etmopterus group. Etmopterus, which boasts to be one of the most diverse shark groups, has approximately 42 species belonging to it.
Unique features to the new Barrie’s lanternshark are the arrangement of its markings, the shape and size of the markings and the presence of dermal denticles, which are modified teeth that act as tough scales to protect the skin, at the base of the dorsal fin.
Barrie’s lanternshark has an indistinct colour gradation between its sides and its belly and a V- shaped arrangement of ampullae (electroreceptors) on the bottom surface of its snout. It has a dorsal fin densely covered in dermal denticles, 85-88 vertebrae in its spine and a spiral valve with 11 turns in a corkscrew shaped part of the intestine.
The description of this new species was based on the freshly caught specimens which have been lodged at three museums, the Iziko South African Museum (SAMC) in Cape Town, the South African Institute for Aquatic Biodiversity (SAIAB) in Makhanda, and in the Zoological Museum Hamburg (ZMH) in Germany.
This shark is new to Africa, known to only occur from the west coast of South Africa to the western Agulhas Bank from 480–850m depth, off southern Mozambique in 980–1000m depth and on the southern end of the Madagascar Ridge, southwestern Indian Ocean and at Walters Shoal from about 896–1200m depth.
Along with the new lanternshark, Ebert, Dr Simon Weigmann based in Hamburg Germany and Bernard Séret discovered two new species of rays in the western Indian Ocean. The new species of ray were discovered on closer examination of existing museum specimens where morphological evidence was provided for a complex of species within Grey spot Guitarfish.
“Dr Weigmann and his colleagues split away two new rays from what is commonly known in South Africa known as the Grey spot Guitarfish,” said Olbers.
The two emerging species named the Malagasy Blue-spotted Guitarfish (Acroteriobatus andysabini) and Socotra Blue-spotted Guitarfish (Acroteriobatus stehmanni) are found off the coast of Madagascar and the Socotra Islands in Yemen, respectively. Both species are only found in their respective areas and were shown to occur in areas that do not overlap with each other or the Grey spot Guitarfish.
The two new species both show similarity to the Grey spot Guitarfish but are distinguishable by the differences in their colouration and size.
The new Malagasy Blue-spotted Guitarfish is seen to be the largest of the three species, reaching a total length of more than 100cm. A Socotra Blue-spotted Guitarfish is the smallest of the three species, only reaching 62cm in length. The previously known species, Grey spot Guitarfish is found to be between these two new species with it reaching lengths of 96cm.
“What’s important here is that ‘our’ Grey spot Guitarfish is currently listed as Endangered, but now we know that its range is much more restricted than previously thought, this could change that assessment, with either an up- or downgrade on the IUCN Red List,” said Olbers.
“It would therefore be important that any fisheries management of this species is revised. With this revision, the Grey spot Guitarfish only occurs on the east coast of South Africa north to Tanzania, and not in Madagascar and off Yemen as previously thought. The clarity on physical attributes defining different species and the distribution of these three small-bodied guitarfishes are essential for improved research and effective conservation and management policy decisions.”
Cape Times
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