Evidence for the presence of a pharynx and dorsal/ventral feeding gutters in vetulicolians. (A) Vetulicola monile (ELI-SJ1221A) and (B) Vetulicola rectangulata (ELI-SJ1168A), showing remains of food boluses (arrowed) located along a ventral gutter in posterior region of the pharyngeal cavity. (C,D) Close-up images of boxed areas in (A) and (B), respectively; note that posteriorly the food boluses are in continuity with the intestine within the tail. (E) Heteromorphus longicaudatus (ELI-SJ1247), showing food remains (arrowed) along the ventral side. (F,G) V. rectangulata, specimens ELI-SS004A and SS002A, both showing food remains (arrowed) and rearward constriction of pharynx, indicating site of a putative esophagus. (H,I) V. rectangulata, specimens ELI-EJ05832 and ELI-1033A, both showing an expansion (starred) in proximal region of the intestine, possibly equivalent to a stomach. Abbreviations: Fp, fin-like proboscis; G, gill slit; In, intestine; M, mouth; Mb, membrane; T, tail. Scale bars: 1 cm in (A), (B), (E); 5 mm in (C), (D), (F) to (I).
Ou et al. BMC Biology 2012 10:81 doi:10.1186/1741-7007-10-81