Phylogenetic analysis of &lt;em&gt;Petaloptoctus&lt;/em&gt; (Maldanidae: Polychaeta), with description of a new species from southeastern Brazil

José Eriberto De Assis,Paulo Da Cunha Lana,Martin Lindsey Christoffersen

doi:10.3989/scimar.2010.74n1111

Abstract

We used morphological data for a phylogenetic analysis of the genus Petaloptoctus (Maldanidae: Polychaeta). We found three most parsimonious phylogenetic trees with length = 37, CI = 0.89 and RI = 0.92. The genus Petaloproctus is monophyletic, and is supported by a strongly arched prostomium, pinnate capillary setae, and an anal cup with a reduced dorsal border. Our proposal for the systematisation of the subgroups of Petaloproctus is (( P. tenuis ( P. terriculus + P. neoborealis )) ( P. ornatus ((( P. cirratus + P. dentatus ) ( P. macrodentatus ( P. borealis ( P. vallejoi n. sp. + P. socialis )))))). We also regard Nicomachinae as a monophyletic group with the following synapomorphies: prostomium short and arched; nuchal grooves short and curved; cephalic plate lost; anal pore opening on margin of anal plate. Monophyly of Micromaldane and Nicomache was also supported in the analysis. Petaloproctus vallejoi n. sp. has 19 setigerous and one asetigerous pre-anal segment. The prostomium is rounded, forming a keel with curved laterals. Nuchal grooves are short and deep, strongly curved outwards. Each neuropodium has one acicular spine on setigers 1-3. The pygidium has a large ventral border, and a reduced dorsal border. The anus is terminal, and close to the margin of the anal plate, surrounded by divergent folds.

Highlights

Maldanids are sedentary, tube-builder polychaetes, commonly known as bamboo worms because of the elongate median segments with globose tori at the extremities (Fauchald and Rouse, 1997)
The pygidium may be cone-shaped and bear a truncate plate, or this plate may be within the anal cup (Day, 1967; Hartmann-Schröder, 1971; Fauchald, 1977; Imajima and Shiraki, 1982)
Maldanids are found from the intertidal region to the deep sea (Arwidsson, 1907; Chamberlin, 1919)

Summary

Introduction

Tube-builder polychaetes, commonly known as bamboo worms because of the elongate median segments with globose tori at the extremities (Fauchald and Rouse, 1997). The keel-shaped prostomium is completely fused to the peristomium. The pygidium may be cone-shaped and bear a truncate plate, or this plate may be within the anal cup (Day, 1967; Hartmann-Schröder, 1971; Fauchald, 1977; Imajima and Shiraki, 1982). Maldanids are found from the intertidal region to the deep sea (Arwidsson, 1907; Chamberlin, 1919). Their tubes are constructed both horizontally, with sand and shell fragments under rocks, or vertically, in sandy bottoms with fine and hyaline sand (De Assis et al, 2007a, b)

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Conclusion