Is the Gill Skeleton of Acorn Worms (Enteropneusta) Similar to the Gill Skeleton of Amphioxus (Cephalochordata)?

Is the Gill Skeleton of Acorn Worms (Enteropneusta) Similar to the Gill Skeleton of Amphioxus (Cephalochordata)?
Dokl Biol Sci. 2020 Sep;494(1):232-235
Authors: Ezhova OV, Malakhov VV
Abstract
The gill skeleton of the enteropneust Saccoglossus mereschkowskii consists of a series of tridents. The central prong of each trident bifurcates in its ventral end. The most anterior gill skeletal element has a simple horseshoe shape. Homologues of the elements of the enteropneust gill apparatus were found in the structure of the gill apparatus of Cephalochordata. The organization of the gill skeleton of Enteropneusta and Cephalochordata can be derived from the metameric horseshoe-shaped elements. The similarity of the structure of the gill skeleton of Enteropneusta and Cephalochordata contradicts a common "upside-down theory" of the origin of Chordata.
PMID: 33083879 [PubMed - in process]

Source: Doklady Biological Sciences - September 1, 2020 Category: Biology Authors: Ezhova OV, Malakhov VV Tags: Dokl Biol Sci Source Type: research