We report in this study the occurrence of the larval forms of 13 invertebrate taxa, including an hoplitomella larvae of the boring sponge Thoosa, "lophophorates" larval stages: an actinotroch of phoronids
, ciphonaute of bryozoans and lobate of brachiopods.
In particular, we examined brachiopods, phoronids
, and nemerteans, all of which are closely related to annelids and molluscs (Halanych, 2004; Dunn et al., 2008; Kocot et al., 2010, 2011).
Butterfield, "Early Cambrian 'Soft-Shelled' Brachiopods as Possible Stem-Group Phoronids
," Acta Palaeontologica Polonica 54, no.
Although the tube-building phoronid
, Phoronopsis viridis, tended to decline after the green crab invasion (Fig.
Flow around phoronids
: consequences of a neighbor to suspension feeders.
These data are compared to treatments with compounds that artificially induce behavioral changes and metamorphosis in the actinotroch larvae of other phoronid
species (Herrmann, 1979, 1995).
The hemoglobins of the phoronid
Phoronis architecta (Vandergon and Colacino, 1991) and the polychaete Abarenicola affinis (Wells and Pankhurst, 1980) also appear to be insensitive to sulfide.
Within the Lophophorata, the times to first swimming for the feeding phoronid
and bryozoan bracketed that of the nonfeeding brachiopod.
actinotrocha differs strikingly from both spiralian and deuterostome larval forms in its large, mobile, and muscular oral hood, present throughout growth and development of the larva [ILLUSTRATION FOR FIGURE 1 OMITTED].
Taxon Plumatella repens U12649 Bryozoan Terebratalia transversa U12650 Articulate Glottidia pyramidata U12647 Inarticulate Phoronis vancouverensis U12648 Phoronid
Rhabdopleura normani U15664 Pterobranch Balanoglossus carnosus D14359 Enteropneust Antedon serrata D14357 Crinoid Asterias amurensis D14358 Seastar Artemia salina X01723 Crustacean Placopecten magellanicus X53899 Bivalve Branchiostoma floridae M97571 Cephalochordate Xenopus laevis X04025 Vertebrate Acanthopleura japonica X70210 Chiton Tenebrio molitor X07801 Insect Anemonia sulcata X53498 Cnidarian Sycon calcaravis D15066 Sponge
The mitochondrial genome of Phoronis architecta--comparisons demonstrate that phoronids
are lophotrochozoan protostomes.
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.