The carcass of a stranded southern right whale Eubalaena australis, discovered on the coast of Golfo Nuevo in Península Valdés, Argentina, exhibited extensive orthotopic and heterotopic ossification, osteochondroma-like lesions, and early degenerative joint disease. Extensive soft tissue ossification led to ankylosis of the axial skeleton in a pattern that, in many respects, appeared more similar to a disabling human genetic disorder, fibrodysplasia ossificans progressiva (FOP), than to more common skeletal system diseases in cetaceans and other species. This is the first reported case of a FOP-like condition in a marine mammal and raises important questions about conserved mechanisms of orthotopic and heterotopic ossification in this clade.KEY WORDS: Baleen whale · Ankylosis · Joint disease · Orthotopic/heterotopic ossification · Fibrodysplasia ossificans progressiva · FOP
Resale or republication not permitted without written consent of the publisherDis Aquat Org 102: [149][150][151][152][153][154][155][156] 2012 of SRW in Península Valdés. The SRWHMP conducts systematic beach surveys throughout the calving period when right whales are abundant (June through December) to locate and study beached whale carcasses. Between June 2003 and December 2011, the SRWHMP documented 489 SRW carcasses along the coasts of Península Valdés (V. J. Rowntree et al. unpubl. data). Of these, 12% were adult whales.Vertebral pathology has been widely documented in captive (e.g. Morton 1978, Alexander et al. 1989 and wild cetaceans (e.g. Kompanje 1995a,b, 1999, Berghan & Visser 2000, Kompanje & Garcia Hartmann 2001, Sweeny et al. 2005, Rothschild 2005a,b, Félix et al. 2007, Galatius et al. 2009, Groch et al. 2012) from both baleen (Mysticeti) and toothed whales (Odontoceti). All reported bone or joint diseases described to date have been localized to the vertebral column and were shown or presumed to be degenerative, bacterial, or inflammatory in origin. To date, widespread systemic bone disease has not been described in marine mammals. This work represents the first documented case of severe, generalized orthotopic and heterotopic ossification in a right whale.
MATERIALS AND METHODSThe present study was conducted on a stranded adult male SRW Eubalaena australis found on 14 October 2003 on the coast of Golfo Nuevo (42°46' S, 64°15' W) in Península Valdés, Argentina. The whale was not necropsied when initially found due to logistical constraints. However, morphometric measurements were obtained at that time, and the whale was left to decompose. The skeletal remains of the animal were relocated the following year. Due to the bulk and weight of the carcass, the nearly complete ankylosis of the vertebrae (see 'Results'), and our inability to conduct a thorough pathological evaluation in situ, sections of affected vertebra were removed from the carcass on the beach. A bow saw and electric drill were used to obtain multiple bone samples from both healthy and diseased areas of each vertebra for further gross examination. Addit...