Planonasus parini
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| Weigmann , Stehmann & Thiel , 2013 |
Planonasus parini is a shark in the Pseudotriakidae family that wasfirst described in early 2013. The first specimen, which is also the holotype of the species, wascaughtin 1988/89 by the Russian research vessel Vitjas near the island of Socotra in the north-western Indian Ocean , two more some time later by commercial fishing trawlers in the same area. The name of the genus refers to the flat snout of the species (Latin "planus" = flat, "nasus" = nose). The species epithet parini honors NV Parin, the chief scientist on the 17th voyage of the Vitjas, during which the holotype was caught.
features
Planonasus parini is a small shark, the holotype, a female, is 53 cm long and weighs 560 g. The two other known specimens have a length of about 35 cm. Magnetic resonance imaging of the holotype shows that it is a fully grown specimen and it is believed that the maximum size is 56 cm. The head is relatively long, the muzzle flat and of medium length. The very large mouth opening is bell-shaped. Some of the teeth in the upper jaw form a closely spaced tooth comb, others are three- or five-pointed. Almost all lower jaw teeth are comb-shaped. The labial folds are short. The anterior skin folds at the nostril are short and the inner folds wide. The entire palate is densely covered with papillae of various sizes. The spray holes are very large and are almost vertical. Their length is 4 to 6 times and their height is 2 to 5 times the diameter of the eye. The first dorsal fin has the shape of a long, flat triangle with a rounded upper tip and a narrow free end. It lies between the pectoral and pelvic fins. An interdorsal ridge is missing. The second dorsal fin is much higher than the first, has the shape of an irregular triangle and is opposite the small anal fin. The tail stalk is relatively short and without keels. Planonasus parini is dark gray-brown in color, the sides of the body, the underside of the head and the edges of the fins are darker, the free tip of the first dorsal fin is white.
Planonasus parini differs from the other sharks of the Pseudotriakidae family in that it has fewer vertebrae, a longer head, the absence of a nictitating membrane and the presence of oral papillae. Compared to Gollum and Pseudotriakis , Planonasus parini has an intermediate position in terms of the length of the snout, the number of teeth per row of teeth, the height of the first dorsal fin, the length and width of its free rear section and the caudal peduncle.
Way of life
The way of life of Planonasus parini is completely unknown but probably similar to that of other pseudotriacid sharks. Body shape, fins, skin and muscles suggest a bottom dwelling, lazy, slowly swimming with anguilliform movements and largely inactive shark.
Systematics
Planonasus parini belongs together with three other previously described recent species of the family pseudotriakidae within the order of bull sharks (Carcharhiniformes). A similar previously undescribed species has been caught off the Maldives and may be the closest relative of Planonasus parini .
literature
- Simon Weigmann, Matthias FW Stehmann & Ralf Thiel (2013): Planonasus parini ng and n. Sp., A new genus and species of false cat sharks (Carcharhiniformes, Pseudotriakidae) from the deep northwestern Indian Ocean off Socotra Islands. Zootaxa , 3609 (2): Pages 163-181, ISSN 1175-5334 , doi: 10.11646 / zootaxa.3609.2.3
Web links
- Planonasus parini on Fishbase.org (English)