Phylogeny of basal descendants of cocoon-forming annelids (Clitellata)

Authors : Martin Lindsey CHRISTOFFERSEN

Pages : 95-119

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Molecular analyses have been unsuccessful in placing the clitellates among annelids. Available morphological characters are ordered into congruent transformation series according to Hennigian principles. Orbiniidae is chosen as the outgroup. I propose the following phylogeny [number of apomorphies within brackets]: insert ignore into journalissuearticles values(Clitellata sensu lato [6] insert ignore into journalissuearticles values(Questidae [6] + Apodadrilida, new [2] insert ignore into journalissuearticles values(Parergodrilidae [3] insert ignore into journalissuearticles values(Stygocapitella [3] + Parergodrilus [4]); + Oligochaeta [7] insert ignore into journalissuearticles values(Aphanoneura [2] insert ignore into journalissuearticles values(Aeolosomatidae [2] + Potamodrilidae [3]); + Dorsopharyngea, new [7] insert ignore into journalissuearticles values(Hrabeiellidae, new [6] + Euclitellata [5]););););. Worms with ring-like clitella surrounding the body almost completely are herein renamed Euclitellata. Clitellata is expanded to include all annelids that, in addition to producing cocoons, have sperm receptacles and a restricted number of gonads. Oligochaeta is established as a valid clade for the hermaphroditic annelids bearing few or no chaetae. Questidae, Parergodrilidae, and Hrabeiella belong to Clitellata. Terrestrial `polychaetes`, such as Parergodrilus and Hrabeiella, are actually clitellates. Hrabeiella is the sister group of Euclitellata, despite a secondary loss of spermathecae and clitellum. Aphanoneura belong to Oligochaeta.
Keywords : Key words Euclitellata, Questidae, phylogenetic systematics, plesiomorphic noise, a priori character polarization, methodological bias