spreitzer vertebra

a unique type of anterior caudal vertebrae in which the haemal arch is not closed; the open haemal arches of the first 2-3 caudal vertebrae allowing the expansion of the abdominal cavity posteriorly into the caudal peduncle, especially in adults with swollen gonads. Found in Ammocrypta (Percidae) and named for August Edward Spreitzer who was the first person to report on this type of vertebra (John C. Bruner, pers comm., 2004)