^-^Kr*^ PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES JUL 1 5 1983 Woods HOie, Mass. Vol. 43, No. 8, pp. 87-110, 15 figs. July 6, 1983 MEGAMOUTH-A NEW SPECIES, GENUS, AND FAMILY OF LAMNOID SHARK {MEGACHASMA PELAGIOS, FAMILY MEGACHASMIDAE) FROM THE HAWAIIAN ISLANDS By Leighton R. Taylor Waikiki Aquarium, 2777 Kalakaua Ave., Honolulu, Hawaii 96815 L. J. V. Compagno Tiburon Center for Environmental Studies, San Francisco State University, P.O. Box 855, Tiburon, California 94920 and Paul J. Struhsaker 1050 Koloa St., Honolulu, Hawaii 96816 Abstract: Megachasma pelagios, a new genus and species of lamnoid shark assigned to the new family Megachasmidae, is described and defined from a single adult male, 4.46 m total length. The holotype and only known specimen was collected approximately 42 km ne of Oahu, Hawaii. Structure and habitus distinctly differ from other lamnoid sharks, particularly in head and tooth morphology and in mesopelagic filter feeding. Introduction On 15 November 1976, the research vessel AFB-14 of the Naval Undersea Center (now the Naval Ocean Systems Center), Kaneohe, Hawaii, was conducting oceanographic research in waters about 42 km northeast of Kahuku Point, Oahu, at about 21°51'N and 157°46'W. From 1015 to 1415 Hawaiian Standard Time the ship had de-ployed two large parachutes as sea anchors at a depth of about 165 m in water with a bottom depth of approximately 4600 m. When the para-chutes were hauled to the surface, using a small winch with an 1 80 kg pull shut-off, one of them had entangled in it a large adult male shark 4.46 m (14.6 ft) long and 750 kg (1653 lbs) (Figs. 1-4). Crew members of the AFB-14 realized that the shark was unusual and brought it aboard with much difficulty. The shark was shipped to the Kaneohe Bay facility of the Naval Undersea Cen-ter and tied alongside the dock overnight. The senior author inspected it the next morn-ing. Preliminary examination indicated that it represented a very distinct, undescribed species, and it was decided that it should be preserved intact. Accordingly, the shark was winched out of the water by the tail using a Navy crane, but the caudal fin broke off and the shark fell into the water and had to be retrieved by divers. The shark was quick-frozen at Hawaiian Tuna Pack-ers, Honolulu, while a large preservation tank [87]
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