Their zoological affinities have long been debated, but they likely belong to the Lophothrochozoa (Vinn & Zaton 2012) and could represent stem group phoronids
(Taylor et al.
In particular, we examined brachiopods, phoronids
, and nemerteans, all of which are closely related to annelids and molluscs (Halanych, 2004; Dunn et al.
The recent description of an early Cambrian unmineralized, "soft-shelled" lingulid brachiopod strongly suggests that phoronids
evolved from crown-group brachiopods by the loss of a mineralized shell.
Cohena,, Agata Weydmann (2005) "Molecular evidence that phoronids
are a subtaxon of brachiopods(Brachiopoda: Phoronata) and that genetic divergence of metazoan phylabegan long before the early Cambrian" Organisms, Diversity & Evolution 5 (2005) 253-273
Molecular evidence thai phoronids
are a subtaxon of brachiopods (Brachiopoda: Phoronata) and that genetic divergence of metazoan phyla began long before the Early Cambrian.
Many animals construct simple lined or unlined vertical burrows in a wide range of environments, from insects (Bown 1982) and spiders (Schlirf and Uchman 2005) in continental firmground and overbank deposits, to tube-building annelids and phoronids
(Alpert 1974) in marine settings.
In addition, Skolithos is commonly interpreted as opportunistic, vertical dwelling burrows formed by annelids or phoronids
(Osgood, 1970; Alpert, 1974).
appear to be distasteful to green crabs and in our short-term feeding attempts, we found that starved green crabs would rarely eat them (E.
and sea pens for example) and vagile organisms
They possibly represent stem-group phoronids
(Taylor et al.
However, molecular phylogenetic and developmental analyses have shown that only Entoprocta nests within Spiralia, while ectoprocts often cluster with the phoronids
, the brachiopods, or both, although a monophyletic Lo-phophorata is normally not recognized in recent molecular phylogenies (for discussion, see Halanych, 1996; Mackey et al, 1996; Giribet et al, 2000; Peterson and Eernisse, 2001; Passamaneck and Halanych, 2004, 2006; Philippe et al, 2005; Helmkampf et al, 2008).
are habitants of the marine benthos, each individual produces a chitinous tube in which one moves freely, being able to retract.