Meeting Abstract

P2.204  Saturday, Jan. 5  A New Genus of Marine Tardigrada (Arthrotardigrada) from the Southeastern United States GROSS, V.*; MILLER, W.R.; HOCHBERG, R.; University of Masssachusetts Lowell; Baker University; University of Massachusetts Lowell Vladimir_Gross@student.uml.edu

A new genus of Tardigrada (Heterotardigrada: Arthrotardigrada) is described from the southeastern United States based on unique digit morphology. This discovery was made from a population of tardigrades collected 7 km east of Hutchinson Island near Fort Pierce, Florida at a depth of approximately 10 m. The new genus is characterized by its unique suction pad/claw morphology. On legs IV, the two inner digits each have both a proximal suction pad and a distal claw with a single accessory point, while the two external digits have only suction pads. On legs I-III the two inner digits have both proximal suction pads and distal claws with an accessory point. The anterior external digit also has both a proximal suction pad and a distal claw, but the claw is smooth without an accessory point. The posterior external digit is identical to that of leg IV with only an adhesive pad. This morphology represents an intermediate state between clawless, suction pad-bearing tardigrades and those with claws but lacking suction pads. A related genus, Paradoxipus orzeliscoides Kristensen & Higgens, 1984, was discovered from the same locality, but differs from the one presented here by having both suction pads and claws on every digit of every foot. The nearly cosmopolitan distribution of Orzeliscus (a clawless, suction pad-bearing species) and recent DNA evidence suggest that the presence of suction pads and claws may be plesiomorphic conditions, but the combination of the two on the same foot is relatively derived.