Protodriliformia | |
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Protodrilus mirabilis | |
Scientific classification
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Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Annelida |
Clade: | Pleistoannelida |
Subclass: | Errantia |
Clade: |
Protodriliformia Struck et al. 2015 [1] |
Orders and families | |
Protodriliformia is a clade of small marine polychaetes, comprised by the groups of meiofaunal interstitial worms Protodrilida and Polygordiidae, formerly considered " archiannelids". It is the most basal clade of Errantia. [1] [2]
Phylogenetic analysis of annelids has found Protodriliformia to be the earliest diverging clade of Errantia. At the same time, the other half of " archiannelid" worms, Orbiniida, was found to be the earliest diverging clade of Sedentaria. The convergence between these two groups occurred through progenesis and miniaturization, as a way to adapt to the marine interstitial ecosystem between sand grains (i.e. interstitium). This means that the larval or juvenile stages of a larger pleistoannelid ancestor temporarily inhabiting the interstitium stopped their somatic growth, became sexually mature and stayed in the interstitium permanently. [1]
Pleistoannelida |
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