Meeting Abstract

P2.98  Sunday, Jan. 5 15:30  Early Growth and Development of the Rostrum in Paddlefish (Polyodon spathula) FURIMSKY, M.; BROOKS, M.*; ROBERTSON, J.; Westminster College, New Wilmington, PA; Westminster College, New Wilmington, PA; Westminster College, New Wilmington, PA robertjc@westminster.edu

Paddlefish are native to large river systems of central North America. The rostrum of the paddlefish is not present at hatching, but develops relatively rapidly in young fish. Evidence indicates that this physically significant structure serves important electro- and mechano-sensory functions. Here, we investigate the initiation and pattern of early growth of the rostrum, focusing on the hyaline cartilage that constitutes the central structural element. We examined tissue composition in fish from immediate post-hatch to stages with a well-developed rostrum; we describe the histological transition associated with the initiation of growth of the rostrum, the pattern by which hyaline cartilage growth occurs to extend the rostrum, and the physical relationship of the growing rostrum to the cartilaginous braincase and other structures. We also describe the formation of the medullary cavity – an adipose-filled, vascularized space that forms early in the proximal region of the developing rostrum. To explore the regulation and processes associated with rostrum growth, we used immunohistochemistry with markers for cell proliferation, chondrogenesis and neurogenesis. As a dramatic example of vertebrate post-embryonic morphogenesis, understanding the control of and mechanisms underlying rostrum growth informs developmental regulation, chondrogenesis and skeletogenesis, and sensory augmentation and integration.