''Grippia'' is a

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 early

ichthyopterygia Ichthyopterygia ("fish flippers") was a designation introduced by Richard Owen, Sir Richard Owen in 1840 to designate the Jurassic ichthyosaurs that were known at the time, but the term is now used more often for both true Ichthyosauria and their ...

n, an extinct group of reptiles that resembled

dolphins A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...

. Its only species is ''Grippia longirostris''. It was a relatively small ichthyopterygian, measuring around long.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

remains from

Svalbard Svalbard ( , ), previously known as Spitsbergen or Spitzbergen, is a Norway, Norwegian archipelago that lies at the convergence of the Arctic Ocean with the Atlantic Ocean. North of continental Europe, mainland Europe, it lies about midway be ...

from the specimen SVT 203 were originally assigned to ''G. longirostris'' but are now thought to have belonged to a non-

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeosc ...

related to '' Helveticosaurus''.

Discovery

Fossils have been found along the coasts of

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

, and

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

( Sulfur Mountain Formation); of

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 ...

age. No complete skeletons have ever been found. However, well-preserved remains have been found, with the most notable ones including: *The Marine Ironstone found in Agardh Bay Norway. This specimen consists of a partial

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

fossil; however, it was lost during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

and presumably destroyed. *Previously, the Vega Phroso Siltstone Member of the Sulphur Mountain Formation in

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. This specimen consists of a well preserved

forelimb A forelimb or front limb is one of the paired articulated appendages ( limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used inst ...

, several

ribs The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels ...

, and a single centrum. However, it has now been reclassified as '' Gulosaurus helmi,'' a close relative of ''Grippia.'' The first ''G. longirostris'' skull was found in 1929. Many palaeontologists believe it was the most complete specimen ever found, however, it was destroyed in a bombing raid on

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

in WWII. ''Grippia longirostris'' was an entirely marine

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

and is considered to be the most basal example of

Ichthyopterygia Ichthyopterygia ("fish flippers") was a designation introduced by Richard Owen, Sir Richard Owen in 1840 to designate the Jurassic ichthyosaurs that were known at the time, but the term is now used more often for both true Ichthyosauria and their ...

. ''G. longirostris'' measured in at 1-1.5m (3.3-4.9 feet) in length making it the smallest species within the

superorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Ichthyopterygia. Other definitive features of ''G. longirostris'' include the arrangement of carpals and

metacarpals In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular skeleton, appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones (wrist, wris ...

that constitute the

forelimbs A forelimb or front limb is one of the paired articulated appendages ( limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used inst ...

and the

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

of the

. Members of this species swam via lateral movements of their tail similar to that of a modern-day eel.

Description

The skeletal structure of ''G. longirostris'' has been documented, especially the forelimbs by Ryosuke Motani in 1998 and the skull by Ryosuke Motani in 2000. These studies involved modern documentation and research of previously discovered specimens.

Skull

Several different ''Grippia'' skulls have been analyzed since 1929. Seven well known

cranial Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Thi ...

specimens belonging to ''G. longirostris'' were reanalyzed, in order to construct detailed descriptions of each specimen and to form a coherent compilation to represent the genus as a whole. An important thing to note is how no skull has been found to have a

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, Rostrum (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...

; therefore any descriptions of the snout are speculative. Montani constructed several diagrams based on his analysis, which depict the skull of ''G. longirostris'' as: *Having a narrow shape. *Possessing

orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...

that are larger than the upper

temporal fenestra Temporal fenestrae are openings in the temporal region of the skull of some amniotes, behind the orbit (eye socket). These openings have historically been used to track the evolution and affinities of reptiles. Temporal fenestrae are commonly (al ...

. *The

quadratojugal The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians. Anatomy and function In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and ...

does not enter the upper temporal fenestra. *The anterior margin of the external

naris A nostril (or naris , : nares ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates, ...

is formed by the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

. *The postfrontal have a posterior process that overlaps the bone of the large

postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ve ...

, similar to the skulls of other basal ichthyosaurs.

Forelimbs

The forelimbs of ''G. longirostris'' are characteristic of the species. Descriptions created by Wiman in 1933 originally depicted ''G. longirostris'' as having very primitive forelimbs that were not yet completely specialized for aquatic life. These descriptions involved the presence of “

hoof The hoof (: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with ...

s” at the tips of each digit, this observation has since been discredited. The most recent descriptions of the forelimbs were performed in 1998 by Motani. This analysis focused on one specimen that was nearly complete, although it was determined to be missing several distal segments of the

phalanges The phalanges (: phalanx ) are digit (anatomy), digital bones in the hands and foot, feet of most vertebrates. In primates, the Thumb, thumbs and Hallux, big toes have two phalanges while the other Digit (anatomy), digits have three phalanges. ...

. This study revealed: *''Grippia'' possesses pentadactyl limbs. *The

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

and phalanges are well developed. *It possessed an articular

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

. *The

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

and radius extend in a wide fan shape. *The first four proximal and distal carpals aid in separating the metacarpals. *The second to fourth metacarpals and phalanges are similar to that of other

amniotes Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibious stem tetrapod ancestors during the ...

, however they are flattened. *The first and fifth metacarpals and phalanges are lunate in appearance and concave inwards towards the interior carpals. *The phalanges of the distal end of the fourth and fifth digits appear to take more of an oval shape.

Classification

Ichthyopterygia are fully aquatic reptiles that evolved from terrestrial

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s, with no transitional lineage being discovered so far. ''Grippia'' is one of earliest examples of the

Ichthyopterygia and is fully adapted to aquatic life. ''Grippia'' are believed to have lived from 250 to 235 Ma during the

Olenekian In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...

–

Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...

of the early to mid-Triassic. ''Grippia'' are considered to be basal ichthyosaurs along with several other early genera, with ''Grippia'' being the most basal of all of them. This is due to its primitive

anatomy Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

when compared to older ichthyosaurs and because ''Grippia'' is the most thoroughly studied out of all basal ichthyosaurs. 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 ...

which represents Ichthyopterygia showing how ''Grippia'' diverged early in the lineage.

Paleobiology

''G. longirostris'' were well adapted to an aquatic lifestyle during early – mid Triassic. They inhabited equatorial to equatorial shallow coastal seas. This paleohabitat was based upon how areas where fossils are found were at equatorial latitudes during the early Triassic when these animals lived. The exact diet of these animals is highly debated. Analysis of dental remains belonging to ''G. Longirostris'' has shown blunt posterior teeth and replacement

maxillary teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearin ...

, which suggests that these animals practiced an

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

feeding style. This evidence is contradictory when cross examined against previous work done in the thirties and eighties, which theorized that ''G. Longirostris'' practiced a diet specialized in

mollusca Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

and small

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

. All of these results were based on samples that did not include an existing snout, therefore they were highly speculative and paleontologists will not know what these animals ate until a full skull is found.

Paleoecology

It is hypothesised that ''Grippia'' became extinct because it was outcompeted by more advanced ichthyosaurs. This limited the amount of food that ''Grippia'' could secure, eventually leading it to its extinction around 235 Ma.

References

External links

Grippia - A Triassic Ichthyosaur (Backup at Wayback Machine)Grippia Longirostris Wilman 1929
{{Taxonbar, from1=Q18578320, from2=Q1014860 Triassic ichthyopterygians Early Triassic reptiles of Asia Triassic reptiles of North America Olenekian life Anisian life Ichthyosauromorph genera Taxa with lost type specimens