The origin and early evolution of lophotrochozoans remain a difficult but crucial issue in reconstructing metazoan phylogeny. Exceptionally preserved fossils have provided hopeful information for resolving this lophotrochozoan problem. Here we identify that Conicula striata, a soft-bodied conical animal from the early Cambrian Chengjiang Lagerstätte, has mosaic characteristics of different lophophorate phyla. C. striata possesses a phoronid-like vermiform trunk housing a U-shaped gut and a coiled lophophore comprising ≥12 arms with numerous tentacles, but it also bears brachiopod-like features including an undivided mantle enclosing lophophore and a pedicle-like protrusion on annulated trunk. Phylogenetic analysis retrieves C. striata as a total-group lophophorate and as an intermediate taxon between Phoronida and Brachiopoda. This suggests that the bivalved architecture of brachiopods originated from an undivided mantle in a phoronid-like ancestor, and that the ancestral vermiform trunk became reduced during the origin of Brachiopoda, illuminating the origins of body plans in the lophophorate phyla.
The western Mongolian Lake Zone was a Neoproterozoic to early Paleozoic volcanic arc where tuffs, lavas, fossiliferous siliciclastics, and carbonates accumulated during the early Cambrian. An uppermost Cambrian Series 2 (upper Stage 4) trilobite assemblage is described here from the Burgasutay Formation representing a continuous lower Cambrian succession at the Seer Ridge of the Great Lake Depression. The new assemblage is dominated by dorypygids and consists of 13 trilobite genera belonging to nine families including Catinouyia heyunensis new species. These fossils comprise the youngest and richest lower Cambrian trilobite assemblage in Mongolia. The composition of the Lake Zone fauna suggests its biogeographic affinity with the Siberian Platform and Altay-Sayan Foldbelt, but the presence of inouyiids also implies a connection of this region with East Gondwana. UUID: http://zoobank.org/fb0ebe23-144f-46ed-9543-7df9eea85fbc
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