''Eretmorhipis'' (meaning "oar fan" from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

'' '', "oar", and '' '', "fan") is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of hupehsuchian

marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including mari ...

s from the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

of China. It is currently known from two specimens that were discovered in an exposure of the Jialingjiang Formation in Yuan'an County,

Hubei Hubei is a province of China, province in Central China. It has the List of Chinese provincial-level divisions by GDP, seventh-largest economy among Chinese provinces, the second-largest within Central China, and the third-largest among inland ...

, and referred to the newly named species ''Eretmorhipis carrolldongi'' in 2015. ''Eretmorhipis carrolldongi'' is noted for its exceptionally small eyes relative to the body,

platypus The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal endemic to eastern Australia, including Tasmania. The platypus is the sole living representative or monotypi ...

-like snout, and plates on its back "like a

stegosaurus ''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been fo ...

." One of those specimens, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

WGSC V26020, had been known since 1991 and consists of the entire skeleton excluding the skull. The second specimen, IVPP V4070, is an impression of the right side of the back half of the skeleton, as well as part of the right fore limb. Two more specimens were discovered in 2018 at the same location, one of which is almost complete and includes the skull.

Description

''Eretmorhipis'' was a relatively small reptile, with the second specimen IVPP V4070 measuring about in total body length. It is unique among hupehsuchians in having manual and pedal digits that radiate in a fan-like shape. Like other hupehsuchians, it has three overlapping layers of armor-like

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amph ...

s over its spine, but the osteoderms of the uppermost layer are significantly larger than they are in other hupehsuchians, each spanning the length of four vertebrae. These upper-layer osteoderms are also widely spaced. The torso of ''Eretmorhipis'' is elongated and encased in a bony tube formed from thickened ribs and

gastralia Gastralia (: gastralium) are dermal bones found in the ventral body wall of modern crocodilians and tuatara, and many prehistoric tetrapods. They are found between the sternum and pelvis, and do not articulate with the vertebrae. In these reptil ...

, similar to the bony tube of the hupehsuchian ''

Parahupehsuchus ''Parahupehsuchus'' is an extinct genus of hupehsuchian marine reptiles from the Early Triassic of China. The genus is monotypic, known from the single species ''Parahupehsuchus longus'' and based on a single specimen. Like other hupehsuchians ...

'', but less extensive.

Discovery

The first specimen, discovered in the 1991, was missing a head. The next, more complete, fossils were found in 2015 by Wong Cheng of the Wuhan Center of China Geological Survey.

University of California, Davis The University of California, Davis (UC Davis, UCD, or Davis) is a Public university, public Land-grant university, land-grant research university in Davis, California, United States. It is the northernmost of the ten campuses of the University ...

paleobiologist Ryosuke Motani told ''

The New York Times ''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of ...

'' that the animal's odd features initially stunned him: "When I first saw it, I just said ‘What?!’ and didn’t speak for a while."

Classification

The authors of the 2015 paper that named ''Eretmorhipis'' performed a

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis and found that it was one of the most derived hupehsuchians, forming a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

that they called the Parahupehsuchinae with ''Parahupehsuchus'' and an unnamed polydactylous hupehsuchian. Below is a

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

from their analysis:

References

External links

"And You Thought the Platypus Was Odd"
"Trilobites," NY Times, Jan. 24, 2019 Early Triassic reptiles of Asia Hupehsuchia Fossil taxa described in 2015 Paleontology in Hubei Ichthyosauromorph genera {{triassic-reptile-stub