Vetulicolia
Encyclopedia
VetulicoliaThe phylum name, Vetulocolia, is derived from the type genus, Vetulicola
, which is a compound Latin word composed of vetuli, or "old," and cola, or "inhabitant."
is an extinct phylum
encompassing several Cambrian
organisms. Their bodies comprise two parts; their front is voluminous and is tipped with a large "mouth" and a row of five round to oval-shaped features on each side which have been interpreted as gills - or at least openings in the vicinity of the pharynx
. Their posterior section comprises seven segments. They lack preserved appendages of any kind. The area where the anterior and posterior parts join is constricted. Their affinity is very uncertain; they have been considered to represent stem- and crown-group arthropods, stem-group vertebrates, and early deuterostome
s.
(Didazoon
, Pomatrum, and Xidazoon
) and the Vetulicolidae (Vetulicola
, and Banffia
). Other groups which may be related include the yunnanozoan
s.
The taxonomic placement of the Vetulicolians remains controversial. Shu (2003) has argued that the vetulicolians probably represent an early side-branch of deuterostomes, and that this implies that segmentation in cephalochordates and vertebrate
s may be derived from the common ancestor of protostome
s and deuterostomes. Briggs et al. (2005) described Skeemella from the Middle Cambrian of Utah as having affinity to Vetulicolia, but also as having arthropod
features, thus confounding assignment of Vetulicolia to Deuterostomia. Dominguez and Jefferies have argued, based on morphological
analysis, that Vetulicola (and by implication, other Vetulicolians) is a urochordate, and probably a stem-group larvacean. However, some question the relation to tunicates and larvaceans, as there is no evidence of segmentation in tunicates, larval or adult, that is comparable to segmentation in vetulicolians, that the anus of urochordates is within the atrium, while that of vetulicolians is positioned at the terminal end of the tail, and, perhaps most importantly, there is no exhalant siphon, or analogous structure, seen in vetulicolians.
s) than other groups, such as the tadpole-like Didazoonidae. Because all vetulicolians had mouths which had no features for chewing or grasping, it is automatically assumed that they were not predators. Because of their gill slits, many researchers regard the vetulicolians as being planktivores. The sediment infills in the guts of their fossils have led some to suggest that they were deposit feeders. This idea has been contested, as deposit feeders tend to have straight guts, whereas the hindguts of vetulicolians were spiral-shaped. Some researchers propose that the vetulicolians were "selective deposit-feeders" which actively swam from one region of the seafloor to another, while supplementing their nutrition with filter-feeding.
Vetulicola
Vetulicola is a genus of small, Early Cambrian animals from the Chengjiang biota of China.-Description:The type species, Vetulicola cuneata has a body composed of two distinct parts of approximately equal length. The front part is rectangular with a carapace-like structure of four rigid cuticular...
, which is a compound Latin word composed of vetuli, or "old," and cola, or "inhabitant."
is an extinct phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
encompassing several Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
organisms. Their bodies comprise two parts; their front is voluminous and is tipped with a large "mouth" and a row of five round to oval-shaped features on each side which have been interpreted as gills - or at least openings in the vicinity of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
. Their posterior section comprises seven segments. They lack preserved appendages of any kind. The area where the anterior and posterior parts join is constricted. Their affinity is very uncertain; they have been considered to represent stem- and crown-group arthropods, stem-group vertebrates, and early deuterostome
Deuterostome
Deuterostomes are a superphylum of animals. They are a subtaxon of the Bilateria branch of the subregnum Eumetazoa, and are opposed to the protostomes...
s.
Taxonomy and evolution
As originally proposed, the phylum included the DidazoonidaeDidazoonidae
Didazoonidae is a family of Vetulicolians containing the species Didazoon haoae, Pomatrum ventralis and Xidazoon stephanus. Their fossils are from the Maotianshan shales Cambrian Lagerstätte....
(Didazoon
Didazoon
The genus Didazoon was erected by Shu, et al. based on fossils found in the Qiongzhusi Formation, Yu'anshan Member , Lower Cambrian, in the Dabanqiao area , about 60 km northwest of Chengjiang, China...
, Pomatrum, and Xidazoon
Xidazoon
The genus Xidazoon was erected by Shu, et al. based on fossils found in the Qiongzhusi Formation, Yu'anshan Member , Lower Cambrian, Haikou, , about 50 km west of Chengjiang, China. It currently consists of the single species Xidazoon stephanus.The fossils show that the body of the animal...
) and the Vetulicolidae (Vetulicola
Vetulicola
Vetulicola is a genus of small, Early Cambrian animals from the Chengjiang biota of China.-Description:The type species, Vetulicola cuneata has a body composed of two distinct parts of approximately equal length. The front part is rectangular with a carapace-like structure of four rigid cuticular...
, and Banffia
Banffia
Banffia is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial.- Anatomy :...
). Other groups which may be related include the yunnanozoan
Yunnanozoon
Yunnanozoon lividum is a suspected a hemichordate or chordate from the Lower Cambrian, Chengjiang biota of Yunnan province, China....
s.
The taxonomic placement of the Vetulicolians remains controversial. Shu (2003) has argued that the vetulicolians probably represent an early side-branch of deuterostomes, and that this implies that segmentation in cephalochordates and vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s may be derived from the common ancestor of protostome
Protostome
Protostomia are a clade of animals. Together with the deuterostomes and a few smaller phyla, they make up the Bilateria, mostly comprising animals with bilateral symmetry and three germ layers...
s and deuterostomes. Briggs et al. (2005) described Skeemella from the Middle Cambrian of Utah as having affinity to Vetulicolia, but also as having arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
features, thus confounding assignment of Vetulicolia to Deuterostomia. Dominguez and Jefferies have argued, based on morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
analysis, that Vetulicola (and by implication, other Vetulicolians) is a urochordate, and probably a stem-group larvacean. However, some question the relation to tunicates and larvaceans, as there is no evidence of segmentation in tunicates, larval or adult, that is comparable to segmentation in vetulicolians, that the anus of urochordates is within the atrium, while that of vetulicolians is positioned at the terminal end of the tail, and, perhaps most importantly, there is no exhalant siphon, or analogous structure, seen in vetulicolians.
Ecology and Lifestyle
From their superficially tadpole-like forms, leaf or paddle-shaped tails, and various degrees of streamlining, it is assumed that all vetulicolians discovered thus far were swimming animals that spent much, if not all, of their time living in the water column. Some groups, like the genus Vetulicola, were more streamlined (complete with ventral keelKeel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
s) than other groups, such as the tadpole-like Didazoonidae. Because all vetulicolians had mouths which had no features for chewing or grasping, it is automatically assumed that they were not predators. Because of their gill slits, many researchers regard the vetulicolians as being planktivores. The sediment infills in the guts of their fossils have led some to suggest that they were deposit feeders. This idea has been contested, as deposit feeders tend to have straight guts, whereas the hindguts of vetulicolians were spiral-shaped. Some researchers propose that the vetulicolians were "selective deposit-feeders" which actively swam from one region of the seafloor to another, while supplementing their nutrition with filter-feeding.
Classification
- Phylum Vetulicolia
- Class Vetulicolida
- Order Vetulicolata
- Family Vetulicolidae
- Genus VetulicolaVetulicolaVetulicola is a genus of small, Early Cambrian animals from the Chengjiang biota of China.-Description:The type species, Vetulicola cuneata has a body composed of two distinct parts of approximately equal length. The front part is rectangular with a carapace-like structure of four rigid cuticular...
- Vetulicola rectangulata
- Vetulicola cuneata
- Vetulicola gangtoucunensis
- Vetulicola monile
- Genus OoedigeraOoedigeraOoedigera peeli is an extinct deuterostome from the Early Cambrian Sirius Passet Lagerstatte of Greenland. So far, it is the third described vetulicolian that is not restricted to the Maotianshan Shales .-Anatomy:O...
Vinther et al 2011- O. peeli
- Genus Vetulicola
- Family Beidazooidae
- Genus Beidazoon
- Beidazoon venustum (synonym = Bullivetula variola)
- Genus Beidazoon
- Family DidazoonidaeDidazoonidaeDidazoonidae is a family of Vetulicolians containing the species Didazoon haoae, Pomatrum ventralis and Xidazoon stephanus. Their fossils are from the Maotianshan shales Cambrian Lagerstätte....
- Genus DidazoonDidazoonThe genus Didazoon was erected by Shu, et al. based on fossils found in the Qiongzhusi Formation, Yu'anshan Member , Lower Cambrian, in the Dabanqiao area , about 60 km northwest of Chengjiang, China...
- Didazoon haoae
- Genus XidazoonXidazoonThe genus Xidazoon was erected by Shu, et al. based on fossils found in the Qiongzhusi Formation, Yu'anshan Member , Lower Cambrian, Haikou, , about 50 km west of Chengjiang, China. It currently consists of the single species Xidazoon stephanus.The fossils show that the body of the animal...
- Xidazoon stephanus
- Genus Pomatrum
- Pomatrum ventralis
- Genus Didazoon
- Family Vetulicolidae
- ?Order Yunnanozoa
- Family Yunnanozoonidae
- Genus YunnanozoonYunnanozoonYunnanozoon lividum is a suspected a hemichordate or chordate from the Lower Cambrian, Chengjiang biota of Yunnan province, China....
- Yunnanozoon lividum
- Genus HaikouellaHaikouellaHaikouella is a probable chordate from the Lower Cambrian Maotianshan shales of Chengjiang County in Yunnan Province, China.It is similar to the form Yunnanozoon, which is possibly a hemichordate. Still, there are anatomical differences from Yunnanozoon, including a larger stomach and smaller ...
- Haikouella lanceolata
- Genus Yunnanozoon
- Family Yunnanozoonidae
- Order Vetulicolata
- Class Banffozoa
-
-
-
- SkeemellaSkeemellaSkeemella clavula is an elongate animal from what is now the Middle Cambrian Wheeler Shale lagerstatten, of Utah....
clavula
- Skeemella
-
- Family Banffiidae
- Genus BanffiaBanffiaBanffia is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial.- Anatomy :...
- Banffia constricta
- Genus Banffia
-
-
- Class Heteromorphida
-
- Family Heteromorphidae
- Genus Heteromorphus
- Heteromorphus longicaudatus (synonym=Banffia confusa)
- "Form A" (unnamed species)
- Genus Heteromorphus
- Family Heteromorphidae
-
- Class Vetulicolida
- incertae sedisIncertae sedis, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
YuyuanozoonYuyuanozoonYuyuanozoon magnificissimi is the largest known vetulicolian, with the holotype measuring about 202 millimeters in length. In life, it would have been an egg-shaped animal with a long cylindrical tail...
magnificissimi
External links
- New phylum on the block - Accessed January 3, 2008
- Once We Were Worms
- Photos and drawings of fossils of various Vetulicolians - Accessed January 3, 2008