Meeting Abstract

P3.11  Thursday, Jan. 6  New insights on morphology of feeding and the evolution of the sessile lifestyle: Species of Stephanoceros HOCHBERG, A.*; HOCHBERG, R.; University of Massachusetts Lowell; University of Massachusetts Lowell Adele_Hochberg@student.uml.edu

Species of Stephanoceros are sessile rotifers that reside in gelatinous tubes, have a body that is vase-shaped, and possess an unusual, basket-like corona. Sessility is a relatively rare lifestyle among monogonont rotifers, known from more than 100 species distributed in one clade, the Gnesiotrocha. The sessile lifestyle is a derived condition within the Rotifera, requiring adaptations to different food sources and reproductive modes. Still, many sessile species are not significantly different in external morphology compared to their planktonic relatives. In this study, we examine the morphology of a group of species that do show a dramatic departure from the “typical” rotifer condition, be it planktonic or sessile. Species of Stephanoceros are unusual in the structure of their anterior end, where they have evolved a basket-like head morphology that is presumably an adaptation to food collection. Here we use phalloidin, anti-FMRFamide, and DAPI staining along with confocal laser scanning microscopy to explore the topology of the muscular and nervous systems, in order to gain insights into the functional morphology of feeding and the evolution of the sessile lifestyle.