Vetulicola is a type of marine animal that no longer exists. It was found in China during the Cambrian period. It is the namesake of the mysterious group Vetulicolia, whose classification is unknown but might be related to deuterostomes. The name Vetulicola comes from the first species discovered, Vetulicola cuneata, which was described by Hou Xian-guang in 1987. This species was found in the Lower Cambrian Chiungchussu Formation in Chengjiang, China.

Etymology

The word Vetulicola is made up of two parts. The first part, "vetulus," comes from Latin and means "old" or "ancient." The second part, "-cola," also comes from Latin and means "someone who lives in a place."

Description

The type species, Vetulicola cuneata, was first described by a scientist named Hou Xian-guang in 1987. It has a body shape similar to arthropods and is divided into two parts of nearly equal length. The front part is rectangular and has a structure resembling a hard shell, made of four rigid plates. A large mouth is located at the front end of this section. The back part is long and tough, positioned on top of the body. Pairs of openings run along the sides, connecting the throat to the outside. These openings are thought to be early forms of gill slits. Vetulicola cuneata could grow up to 9 centimeters in length. Scientists believe these creatures were swimmers that may have filtered food from water.

Other Vetulicola species include Vetulicola rectangulata (Luo and Hu, 1999), V. gantoucunensis (Luo et al., 2005), V. monile (Aldridge et al., 2007), and V. longbaoshanensis (Yang et al., 2010). The mouths of all other species are smaller and do not stick out like those of V. cuneata. All species, except V. gantoucunensis, are smaller than the type species.

Taxonomy

Vetulicola is the namesake genus of the family Vetulicolidae, which also includes the genera Ooedigera and Beidazoon.

The family has been found to be a monophyletic clade, even in a 2024 analysis that showed Vetulicolia and Vetulicolida as paraphyletic. However, the same analysis found that the only species in Beidazoon, B. venustrum, is more closely related to V. monile than V. monile is to other members of Vetulicola.

Species in the genus Vetulicola include:
– Vetulicola gantoucunensis †
– Vetulicola longbaoshanensis †
– Vetulicola rectangulata †

The dagger (†) symbol indicates that these species are extinct.

An earlier study in 2014 considered Vetulicola to be monophyletic but could not determine how the different groups within the Vetulicolidae family were related. Other species studied in this analysis included Pomatrum † and Xidazoon †.

Paleobiology

Vetulicola was the host of the symbiotic organism Vermilituus gregarius, which lived inside the front part of Vetulicola's body. About 2% of Vetulicola individuals had Vermilituus present, but when it was present, it could be very common. One Vetulicola specimen had 88 Vermilituus individuals inside it. These large numbers of Vermilituus likely caused harm to the host Vetulicola.