RESEARCH ARTICLE A new microendemic species of the deep- water catshark genus Bythaelurus (Carcharhiniformes, Pentanchidae) from the northwestern Indian Ocean, with investigations of its feeding ecology, generic review and identification key 1,2 3 2 Simon WeigmannID *, Carina Julia KaschnerID , Ralf Thiel a1111111111 1 Elasmo-Lab, Elasmobranch Research Laboratory, Hamburg, Germany, 2 Center of Natural History, a1111111111 University of Hamburg, Hamburg, Germany, 3 Department 522, Fisheries, Federal Office for Agriculture and a1111111111 Food, Hamburg, Germany a1111111111 a1111111111 *
[email protected] Abstract OPEN ACCESS A new deep-water catshark, Bythaelurus stewarti, is described based on 121 examined Citation: Weigmann S, Kaschner CJ, Thiel R specimens caught on the Error Seamount (Mount Error Guyot) in the northwestern Indian (2018) A new microendemic species of the deep- Ocean. The new species differs from all congeners in the restricted distribution, a higher spi- water catshark genus Bythaelurus ral valve turn count and in the morphology of the dermal denticles. It is distinguished from its (Carcharhiniformes, Pentanchidae) from the northwestern Indian Ocean, with investigations of morphologically and geographically closest congener, B. hispidus (Alcock), by the larger its feeding ecology, generic review and size (maximum size 44 vs. 39 cm TL, maturity size of males 35±39 vs. 21±28 cm TL), darker identification key. PLoS ONE 13(12): e0207887. fresh coloration and dark grayish-brown mottling of the ventral head (vs. ventral head typi- https://doi.org/10.1371/journal.pone.0207887 cally uniformly yellowish or whitish). Furthermore, it has a strongly different morphology of Editor: Ulrike Gertrud Munderloh, University of dermal denticles, in particular smaller and less elongate branchial, trunk and lateral caudal Minnesota, UNITED STATES denticles that are set much less densely and have a surface that is very strongly and fully Received: August 24, 2018 structured by reticulations (vs.