Meeting Abstract

P1.89  Thursday, Jan. 3  Larval Velar Morphology in a Neogastropod: Implications for the Evolution of Structure and Function VENDETTI, Jann E.; University of California, Berkeley jannv@berkeley.edu

Planktonic gastropod veliger larvae move through the water column via the ciliary motion of their velum. The morphology of velar lobes varies greatly, as do the secondary functions of these structures. In buccinid gastropods, larval development begins within a benthic egg capsule, and velar morphology can reflect different intracapsular and post-hatching functions. For example, species that hatch with a planktonic developmental phase may or may not have velar morphology capable of feeding, and non-planktonic developers may or may not have velar morphology exapted for intracapsular adelphophagy or nurse-egg feeding. To understand the function of intra and extra capsular velar morphology in a buccinid gastropod with a planktonic developmental phase, I observed Kelletia kelletii veligers. I tested for particle capture and transport by velar cilia using algae and fluorescent micro-particles. Structural features of the velum were visualized using Scanning Electron Microscopy (SEM). Larvae were also examined for the following characteristics: internal yolk reserves prior to and post hatching, intracapsular feeding, a metatroch prior to and post hatching, and asymmetrical velar lobe development. Results suggest that opposed band cilia on velar lobes are capable of particle capture and transport. Also, the velum is functional for swimming before larvae hatch naturally from their capsules, development is asymmetrical, and endogenous egg stores are present in veligers at hatching. These data, combined with what we know of larval ontogeny in other buccinid gastropods, contribute to the understanding of evolutionary trends from feeding to non-feeding and planktonic to non-planktonic, as well as the origins of suites of associated structural features.