Meeting Abstract
Giant nematodes (>3m) of the Family Crassicaudidae are known to infect kogiid whales. Only two studies to date have provided detailed descriptions of these Crassicauda worms, based upon fragmented specimens including a female head (Johnson and Mawson, 1939) and a male tail (Dollfus, 1966). Both studies described worms within the neck region of kogiids, an unusual anatomic site for this family of nematodes. At SICB last year we demonstrated crassicaudids to be a species-specific parasite among kogiids, infecting only Kogia breviceps, and confirmed its primarily cervicothoracic distribution. To date, though, the exact anatomic location and potential transmission path of this parasite are unknown. Thus, our goal was to identify the worm’s pattern of habitat use within K. breviceps using historic necropsy reports (n=64), detailed gross dissections (n=6), histology (n=2), and non-invasive imaging techniques (n=1). We discovered that a critical habitat for the worm is a previously undescribed exocrine gland, located at the terminus of the pigmented “false gill slit” in the ventral cervical region of the whale. Preliminary results suggest this is a compound tubuloalveolar gland with a central lumen. Male and female tails were found entwined and hanging freely within the lumen of this gland, and eggs have been observed in its presumed exudate, illuminating the potential transmission path out of the host body. The cephalic end of these worms are found, often meters away, embedded deep within the host’s epaxial muscle. We describe in detail a single parasite’s tortuous 312cm course from the gland to its termination in the contralateral epaxial muscle of its definitive host, K. breviceps.
