Lotosaurus
Encyclopedia
Lotosaurus is an is an extinct genus
of sail
-backed poposauroid
known from Hunan Province of central China
.
IVPP V 4881 (or possibly V 4880), articulate
d well-preserved skeleton
, and from the referred specimens IVPP V 48013, skull
, articulated and disarticulated skeletal remains of at least ten individuals, all came from a monotypic bonebed. All specimens were collected from the Lotosaurus site, from the Batung Formation (or alternatively Xinlingzhen Formation of the Badong Group), dating to the Anisian
stage of the early Middle Triassic
, about 245-237 million years ago.
Lotosaurus was 2.5 m (8.2 ft) long and a heavily built quadruped
. It was a herbivore
, biting off leaves with its toothless jaw
s. Lotosaurus, like some other members of the Poposauroidea
, had a sail on its back. It looked similar to that of Permian
pelycosaur
s like Dimetrodon
and Edaphosaurus
, although not as high.
Lotosaurus was originally thought to be a thecodont
, probably related to Ctenosauriscus
and other
archosaur taxa with elongated neural spines (=Ctenosauriscidae
). Many recent cladistic analyses confirmed this affinity. Nesbitt (2007) was the first to suggest that Lotosaurus is more closely related to Shuvosaurus
(a shuvosaurid) than to Arizonasaurus
(a ctenosauriscid). In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt (2011) found Lotosaurus to be a poposauroid, sister group of the Shuvosauridae
, and therefore it is not included in the Ctenosauriscidae
. Further studies confirmed these results.
and the type species
is Lotosaurus adentus. Lotosaurus was originally placed in its own family
, Lotosauridae, which named by Zhang in 1975. The specific name is derived from the Greek
a and denta, meaning "toothless", in reference to its toothless beak.
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 sail
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
-backed poposauroid
Poposauroidea
Poposauroidea is a clade of rauisuchians. It includes poposaurids, shuvosaurids, and ctenosauriscids, but excludes the large predatory quadrupedal rauisuchians such as rauisuchids and prestosuchids. Although it was first formally defined in 2007, the term has been used for many years...
known from Hunan Province of central 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...
.
Description
Lotosaurus is known from the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
IVPP V 4881 (or possibly V 4880), articulate
Articulate
Articulate may refer to:*Articulate *Articulate sign*Articulate sound*Joint, also known as articulation*Word modified by an article...
d well-preserved skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, and from the referred specimens IVPP V 48013, skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
, articulated and disarticulated skeletal remains of at least ten individuals, all came from a monotypic bonebed. All specimens were collected from the Lotosaurus site, from the Batung Formation (or alternatively Xinlingzhen Formation of the Badong Group), dating to the Anisian
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 245 million years ago until 237 million years ago, approximately...
stage of the early Middle Triassic
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...
, about 245-237 million years ago.
Lotosaurus was 2.5 m (8.2 ft) long and a heavily built quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
. It was a herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, biting off leaves with its toothless jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s. Lotosaurus, like some other members of the Poposauroidea
Poposauroidea
Poposauroidea is a clade of rauisuchians. It includes poposaurids, shuvosaurids, and ctenosauriscids, but excludes the large predatory quadrupedal rauisuchians such as rauisuchids and prestosuchids. Although it was first formally defined in 2007, the term has been used for many years...
, had a sail on its back. It looked similar to that of Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
pelycosaur
Pelycosaur
The pelycosaurs are an informal grouping composed of basal or primitive Late Paleozoic synapsid amniotes. Some species were quite large and could grow up to 3 meters or more, although most species were much smaller...
s like Dimetrodon
Dimetrodon
Dimetrodon was a predatory synapsid genus that flourished during the Permian period, living between 280–265 million years ago ....
and Edaphosaurus
Edaphosaurus
Edaphosaurus is a genus of prehistoric synapsid which lived around 303 to 265 million years ago, during the late Carboniferous to early Permian periods. The name Edaphosaurus means "ground lizard" and is derived from the Greek edaphos/εδαφος and σαυρος/sauros...
, although not as high.
Lotosaurus was originally thought to be a thecodont
Thecodont
Thecodont , now considered an obsolete term, was formerly used to describe a diverse range of early archosaurs that first appeared in the Latest Permian and flourished until the end of the Triassic period...
, probably related to Ctenosauriscus
Ctenosauriscus
Ctenosauriscus is an extinct genus of sail-backed poposauroid archosaur from Early Triassic deposits of Lower Saxony in northern Germany. It gives its name to the family Ctenosauriscidae, which includes other sail-backed poposauroids such as Arizonasaurus...
and other
archosaur taxa with elongated neural spines (=Ctenosauriscidae
Ctenosauriscidae
Ctenosauriscidae is an extinct family of pseudosuchian archosaurs within the clade Poposauroidea. Ctenosauriscids existed in Africa, Asia, Europe and North America during the Early Triassic to the Middle Triassic period . All species had large "sails" on their backs...
). Many recent cladistic analyses confirmed this affinity. Nesbitt (2007) was the first to suggest that Lotosaurus is more closely related to Shuvosaurus
Shuvosaurus
Shuvosaurus is a genus of beaked reptile from the Late Triassic of Texas. It was described by Sankar Chatterjee in 1993 after it was discovered by his son Shuvo. It was initially interpreted as a Triassic member of the Cretaceous dinosaur family Ornithomimidae...
(a shuvosaurid) than to Arizonasaurus
Arizonasaurus
Arizonasaurus was a ctenosauriscid archosaur from the Middle Triassic . Arizonasaurus is found in the Middle Triassic Moenkopi Formation of northern Arizona. A fairly complete skeleton was found in 2002 by Sterling Nesbitt. The taxon has a large sailback formed by elongate neural spines of the...
(a ctenosauriscid). In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt (2011) found Lotosaurus to be a poposauroid, sister group of the Shuvosauridae
Shuvosauridae
Shuvosauridae is an extinct family of theropod-like pseudosuchian within the clade Poposauroidea. Shuvosaurids existed in North and South America during the Late Triassic period...
, and therefore it is not included in the Ctenosauriscidae
Ctenosauriscidae
Ctenosauriscidae is an extinct family of pseudosuchian archosaurs within the clade Poposauroidea. Ctenosauriscids existed in Africa, Asia, Europe and North America during the Early Triassic to the Middle Triassic period . All species had large "sails" on their backs...
. Further studies confirmed these results.
Etymology
Lotosaurus was first named by Fa-kui Zhang in 19751975 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-New taxa:...
and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Lotosaurus adentus. Lotosaurus was originally placed in its own family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, Lotosauridae, which named by Zhang in 1975. The specific name is derived from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
a and denta, meaning "toothless", in reference to its toothless beak.