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Tokyo Bay Sharks

Plate 1. Plate 2. Plate 3. Plate 4.





Plate 1. Plate 2. Plate 3. Plate 4.

*1 & *2: Deania calcea (Lowe, 1839) and Deania historicosa Garman, 1906: Compagno distinguished them by body color (D. calcea; grey-brown, D. historicosa; blackish brown) and crown length of dermal denticle (D. calcea; 0.5 mm, D. historicosa; 1mm). It seems to me that these two markings are not definite evidence for separating them. Both characteristics vary according to age. Denticle and tooth size are proportional to trunk size. Most of species belonging to the genus Deania possess denticle with quadricuspidate except D. historicosa which bears denticle with tricuspidate. In this site, I assigned fish with tricuspidate as D. historicosa. On the other hand, fish with quadricuspidate as D. calcea. Deania quadrispinosum (McCulloch, 1915) bears pitchfork-shaped denticles but its teeth are quite different from those of D. calcea.

*3 & *4: Centrophorus atromarginatus (Garman, 1906): Distance from first dorsal insertion to origin of second dorsal spine is slightly less than distance from tip of snout to pectoral origins. Dermal denticles of lateral trunk showed block like shape with cusp on their posterior edges which is absent in those of C. tessellatus (Garman, 1913) so that I assigned this shark as C. atromarginatus. (Compagno treated C. atromarginatus as a synonym for C. granulosus with a question mark). Two types (variant, Abuka and Siratubo in Japanese) of C. atromarginatus
are known, however they possess almost the same form of dermal denticles and teeth.

Ref., FAO SPECIES CATALOGUE




20100520 Fumio Nakagawa

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