Haplotaxida | |
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Helodrilus caliginosus (Lumbricina: Lumbricidae) | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Annelida |
Clade: | Pleistoannelida |
Clade: | Sedentaria |
Class: | Clitellata |
Order: | Haplotaxida |
Suborders | |
The Haplotaxida are one of two orders within the annelid subclass Oligochaeta, the other being the Lumbriculida. No real common name exists, but they are simply referred to as haplotaxids.
Given that the other clitellatan annelids are embedded between and around the Haplotaxida and Lumbriculida, the traditional Oligochaeta are a paraphyletic assemblage. Thus, the Haplotaxida might eventually be up-ranked to subclass status within the Clitellata or an expanded Oligochaeta, with the present suborders advancing to order rank. The latter – though without merging the Oligochaeta and Clitellata – has been proposed time and again in the past, most prominently for the distinct Moniligastrina.
Of the four suborders of Haplotaxida, two are minor lineages, monotypic at family level. Another one, the Tubificina, is sizeable and contains the aquatic worms, while the fourth, the earthworms or Lumbricina, unites the bulk of the order's families:
Suborder Haplotaxina
Suborder Moniligastrina
Suborder Lumbricina
Suborder Tubificina
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The Clitellata are a class of annelid worms, characterized by having a clitellum – the 'collar' that forms a reproductive cocoon during part of their life cycles. The clitellates comprise around 8,000 species. Unlike the class of Polychaeta, they do not have parapodia and their heads are less developed.
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Palpata is a subclass of polychaete worm. Members of this subclass are mostly deposit feeders on marine detritus or filter feeders. Palpata has become superfluous with the elevation of Canalipalpata to subclass.
Tubificina is a suborder of haplotaxid annelid worms.
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