Diania
Encyclopedia
Diania is an extinct genus
of animal
found in the Lower Cambrian Maotianshan shale of China
, represented by a single species D. cactiformis. Known during its investigation by the nickname "walking cactus", this remarkable organism belongs to a group known as the armoured lobopodia
ns and has a simple worm-like body with robust, spiny, and apparently jointed legs. Its significance is that jointed legs are the defining character of the arthropod
s and Diania may thus be very close to the origins of the most diverse group of animals on the planet.
in Beijing and Michael Steiner of the Free University Berlin. The fossils come from the famous Chengjiang deposit – or Maotianshan shale – of south-west China
and are about 520 million years old. Specifically, they come from the Yu'anshan Formation, dated to the Cambrian Stage 3.
; the province where the fossils were discovered. The specific epithet cactiformis is based on its cactus
-like appearance, which led to it being informally called the "walking cactus" by the research team working on the fossils.
In the original description of the fossil the authors suggested that Diania could be the sister group of Schinderhannes
and the remaining arthropods, but discussed the possibility that it may be a more primitive form emerging before the evolution of creatures like Kerygmachela and Anomalocaris
.
Diania also suggests that that arthropodization (i.e. the appearance of hard ring-like, joints around the legs), evolved before arthrodization (i.e. hard, ring-like segments, around the body). This suggestion, however, has been challenged by a reinterpretation of the phylogenetic position of Diania.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
found in the Lower Cambrian Maotianshan shale of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, represented by a single species D. cactiformis. Known during its investigation by the nickname "walking cactus", this remarkable organism belongs to a group known as the armoured lobopodia
Lobopodia
Lobopodia is a group of poorly understood animals, which mostly fall as a stem group of arthropods. Their fossil range dates back to the Early Cambrian. Lobopods are segmented and typically bear legs with hooked claws on their ends....
ns and has a simple worm-like body with robust, spiny, and apparently jointed legs. Its significance is that jointed legs are the defining character of the 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...
s and Diania may thus be very close to the origins of the most diverse group of animals on the planet.
Discovery
Fossil of these animals were discovered independently by Jianni Liu from the Northwest University (China) in Xi’an, Qiang Ou from the China University of GeosciencesChina University of Geosciences
The China University of Geosciences is a key national university directly under the administration of the Education Ministry of the People's Republic of China...
in Beijing and Michael Steiner of the Free University Berlin. The fossils come from the famous Chengjiang deposit – or Maotianshan shale – of south-west China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and are about 520 million years old. Specifically, they come from the Yu'anshan Formation, dated to the Cambrian Stage 3.
Name
The name Diania comes from "Dian", which is an abbreviation in the Chinese language for YunnanYunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
; the province where the fossils were discovered. The specific epithet cactiformis is based on its cactus
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
-like appearance, which led to it being informally called the "walking cactus" by the research team working on the fossils.
Description
Complete fossils of Diania cactiformis are about 6 centimetres (2.4 in) long and have a long, thin body. At the front end is a proboscis, presumably used in feeding. These animals have ten pairs of legs, and compared to the body these are quite robust and spiny. Because of this spiny appearance in the rocks the animal became known informally as the "walking cactus". The most important aspect is that legs appear to be jointed, with a hard exoskeleton divided into ring-like articles.Significance
Diania belongs to a group of extinct animals known as the armoured Lobopoda. These have long been assumed to be related in some way to Arthropoda and it seems likely that arthropods evolved from somewhere within this group. However, all previously discovered lobopodians showed soft, rather ring-like, but not segmented legs. The significance of Diania is that it is a lobopodian which appears to have evolved the name-giving character of the arthropods: jointed legs.In the original description of the fossil the authors suggested that Diania could be the sister group of Schinderhannes
Schinderhannes
Johannes Bückler , nicknamed Schinderhannes, was a German outlaw who orchestrated one of the most fascinating crime sprees in German history. He was born at Miehlen, the son of Johann and Anna Maria Bückler. He began an apprenticeship to a tanner, but turned to petty theft. At 16 he was arrested...
and the remaining arthropods, but discussed the possibility that it may be a more primitive form emerging before the evolution of creatures like Kerygmachela and Anomalocaris
Anomalocaris
Anomalocaris is an extinct genus of anomalocaridid, which are, in turn, thought to be closely related to the arthropods. The first fossils of Anomalocaris were discovered in the Ogygopsis Shale by Joseph Frederick Whiteaves, with more examples found by Charles Doolittle Walcott in the famed...
.
Diania also suggests that that arthropodization (i.e. the appearance of hard ring-like, joints around the legs), evolved before arthrodization (i.e. hard, ring-like segments, around the body). This suggestion, however, has been challenged by a reinterpretation of the phylogenetic position of Diania.