uniramous and cylindrical, each with three types of chaetae: 1) long, slender lyrate chaeta with small median tooth, 2) bifid chaeta, 3) short and wider chaetae with notched apex.
Morphological and behavioral differences among the three species of orbiniidae Naineris dendritica Leitoscoloplos pugettensis Orbinin johnsoni Broad, shovel-shaped Narrow pointy head Narrow pointy head head Lives in sand Lives in mud Lives in sand Long parapodia
to Short parapodia
to Short parapodia
to body width body width body width No ventral papillae No ventral papillae Ventral papillae No active twisting Active twisting Active twisting No internal body No internal body Internal body movement movement movement We examined burrowing behaviors of these three species in both mud and sand analogs, then related differences in morphologies and burrowing strategies to the differing material properties of their natural environments.
First three parapodia
reduced, with two or three spinigerous chaetae and no cirri (Fig.
Articulated prostomial appendages, lateral dark spots between posterior parapodia
(which occur in the present material), light, tridentate subacicular hooks, and tridentate compound falcigers.
The same part of the sea slug that was exposed to low light between measurements (sideways with closed parapodia
or flat body with open parapodia
, depending on the position taken by the sea slug when immobilized) was used to face the optical fiber during the measurements.
is characterized by having 15-16 thoracic chaetigers with four or five rows of uncini and up to three papilliform postchaetal processes on neuropodial lobes, abdominal parapodia
bearing flail-tipped neurochaetae and lacking furcated notochaetae, branchiae beginning on chaetiger 10 or 11, interramal cirri, and a low number of subpodial and stomach papillae on anteriormost abdominal chaetigers.
Description atokous: syntype complete (MNHN-000), 34 mm long, 2.7 mm wide (including parapodia
), with 95 setigers.
Number of chaeta decreasing progresively from eight in anterior parapodia
to six in posterior ones.
Analogously, the Caribbean sacoglossan Elysia zuleicae engages in group mating behavior that approximates penis fencing, and individuals flap their parapodia
to swim away when another penis makes contact with their body, to avoid receiving an injection of sperm (Krug, per.
Following Mg[Cl.sup.2] anesthesia, broodstock individuals were weighed to the nearest 0.1 g and tagged, for later identification, by attaching color-coded beads to the animal's parapodia
with a small suture of 000 silk.
Region A with 9 chaetigers, parapodia
uniramous except A9, with neuropodia as uncinal plates, notopodial lobes short and simple, lanceolate chaetae just projecting from dorsal to distal surface, lacking cutting spines.
The prostomium and peristomium are fused, forming a retractable head that in most cases (e.g., Flabelligera, Pherusa, and Diplocirrus) is protected by a cage of modified setae from the first few parapodia
(Spies, 1975; Blake, 2000).