Named Galeus friedrichi, the new species is the third species of the catshark genus Galeus — after Galeus sauteri and Galeus schultzi — documented from the Philippines.
Galeus arae, a member of the genus Galeus and a relative of the newly-discovered species Galeus friedrichi. Image credit: NOAA Ocean Explorer.
Galeus is a genus of deepwater catsharks in the family Pentanchidae.
It is one of the most species-rich shark genera with almost 20 scientifically recognized species.
Members of the genus are found in the Atlantic, the western and central Pacific, and the Gulf of California.
They are commonly known as sawtail catsharks, in reference to a distinctive saw-toothed crest of enlarged dermal denticles, found along the upper edges of their caudal fins.
They are harmless and rather small and slim with firm bodies and thick, rough skin. Their heads are usually fairly long and pointed, and have large mouths with well-developed furrows at the corners. Many species are ornately patterned with dark saddles and/or blotches.
They feed on various invertebrates and fishes, and may be either egg-laying or live-bearing.
“Galeus is distinguished from other members of the Pentanchidae family by a combination of its color pattern of blotches and spots, relatively large pectoral fins, as well as the absence of enlarged denticles along the ventral surface of the caudal peduncle which characterizes sharks of the genus Figaro, their closest relatives in the family,” Pacific Shark Research Center marine biologists David Ebert and Jessica Jang wrote in their paper.
“The genus is wide ranging, occurring mostly on outer continental shelves and slopes, and insular slopes from about 100 to 2,000 m deep.”
Galeus friedrichi (the common name is the Philippines sawtail catshark) is known only from type specimens caught off Sikayab-Bukana, Philippines at a depth of 550 m.
It is the third Galeus species found in the Philippines, with Galeus schultzi endemic to the Philippines and Galeus sauteri also occurring off Taiwan.
It can be separated from all regional congeners by a combination of an absence of saddle or blotch patterns on body and caudal fin; large size, exceeding 50 cm total lenght; a higher count of monospondylous vertebrae and precaudal vertebrae.
“Since 2002, nearly one-quarter of all chondrichthyans have been described,” the researchers wrote.
“This renaissance in chondrichthyan taxonomy over the past 20 years has led to the identification of many new species that otherwise could not have been assessed by the IUCN Red List.”
“In fact, three of the 9 sawtail catsharks discussed in our paper have only been named in the past 15 years.”
“Many of these discoveries, including the new species, are deepsea species, highlighting how much remains to be discovered in this environment, especially as fisheries globally expand into the deep sea.”
The paper was published online in the Journal of the Ocean Science Foundation.
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D.A. Ebert & J.J. Jang. 2022. Galeus friedrichi (Carcharhiniformes: Pentanchidae), a new sawtail catshark from the Philippines. Journal of the Ocean Science Foundation 39: 45-53; doi: 10.5281/zenodo.7320085
