''Albertonectes'' (meaning 'Alberta swimmer') is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 large

plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

s that lived in North America during the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

period, at around 73.5million years ago. The only known

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), ...

is ''A. vanderveldei'', described in 2012 from an almost complete postcranial skeleton discovered in 2007 near

Lethbridge Lethbridge ( ) is a city in the province of Alberta, Canada. With a population of 106,550 in the 2023 Alberta municipal censuses, 2023 municipal census, Lethbridge became the fourth Alberta city to surpass 100,000 people. The nearby Canadian ...

, in the

province A province is an administrative division within a country or sovereign state, state. The term derives from the ancient Roman , which was the major territorial and administrative unit of the Roman Empire, Roman Empire's territorial possessions ou ...

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

, Canada. Although currently only documented from 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 ...

, a possible second specimen was discovered in 2015 in the same locality. With a maximum length estimated at , ''Albertonectes'' is the longest known

elasmosaurid Elasmosauridae, often called elasmosaurs or elasmosaurids, is an extinct family of plesiosaurs that lived from the Hauterivian stage of the Early Cretaceous to the Maastrichtian stage of the Late Cretaceous period (c. 130 to 66 mya). The taxo ...

. Like the other representatives of this group, it has a streamlined body with paddle-like limbs, a short tail, a small head, and an extremely long neck. The neck alone is estimated at around long, making ''Albertonectes'' one of the animals with the longest known necks. It is also the

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

with the greatest number of

cervical vertebra In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid s ...

e identified to date, 76, ahead of its close relative ''

Elasmosaurus ''Elasmosaurus'' () is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, at about 80.6 to 77million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, US, and ...

''.

Discovery and naming

The first known specimen of ''Albertonectes'' was discovered in 2007 near the St. Mary River, near the town of

, in southern

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 ...

. It was discovered unexpectedly by an excavator during

ammolite Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of ...

mining carried out by the company

Korite International Korite is the largest commercial producer of ammolite. The company produces natural ammolite gemstones and jewelry. Korite is based in Calgary, Alberta, Canada. The firm's sister company, Canada Fossils Ltd., provides it with ammonites and other ...

Ltd. At the initial moment of the discovery, the excavator accidentally broke part of the fossils coming from the middle of the animal's

trunk Trunk may refer to: Biology * Trunk (anatomy), synonym for torso * Trunk (botany), a tree's central superstructure, and the stem of woody plants * Trunk of corpus callosum, in neuroanatomy * Elephant trunk, the proboscis of an elephant Comput ...

, including an unknown quantity of

gastrolith A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In ...

s (stomach stones). A large part of these fossils have since been noted as lost, and due to the unique character of the specimen as well as its excellent preservation, it was subsequently decided to leave it as is and not to remove any elements found there. This specimen, since housed at the

Royal Tyrrell Museum of Palaeontology The Royal Tyrrell Museum of Palaeontology (RTMP; often referred to as the Royal Tyrrell Museum) is a palaeontology museum and research facility in Drumheller, Alberta, Canada. The museum was named in honour of Joseph Burr Tyrrell, and is situate ...

and numbered as TMP 2007.011.0001, consists of an almost complete and articulated skeleton of a large

, but the

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 ...

is missing. More precisely, it includes 132 vertebrae from the atlas-axis complex to fused tip of the tail vertebrae, a complete

pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectora ...

but an incomplete

pelvic girdle The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the Ilium (bone) ...

, almost complete forelimbs and hindlimbs, disarticulated

rib In vertebrate anatomy, ribs () are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the thoracic cavity, enabling the lungs to expand and thus facilitate breathing by expanding the ...

s, an abdominal rib, and at least 97 associated

s. The skeleton also preserves two teeth coming from the

lamniform The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the g ...

shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

Squalicorax ''Squalicorax'', commonly known as the crow shark, is a genus of extinct lamniform shark known to have lived during the Cretaceous period. The genus had a global distribution in the Late Cretaceous epoch. Multiple species within this genus are co ...

'', the few traces of grooves present on the left

coracoid A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...

indicating that the specimen would have been

scavenged Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding beh ...

after its death.

Stratigraphically Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

, the skeleton was exhumed in an area dating from the middle of the late

of the

Bearpaw Formation The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear ...

, a period located around 73.5 million years ago. In 2012, Japanese paleontologist Tai Kubo and his Canadian colleagues Mark T. Mitchell and Donald M. Henderson described the specimen as the

of a new

and

named ''Albertonectes vanderveldei''. The genus name ''Albertonectes'' comes from Alberta, in reference to the

where the animal was discovered, and from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

word (, "swimmer"). The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

is named in honor of Rene Vandervelde, the founder of the Korite International, the gem-mining company that discovered the holotype. ''Albertonectes'' represents the first significantly complete plesiosaur to be discovered in the Bearpaw Formation, as well as the second elasmosaurid to be identified in the same formation after ''

Terminonatator ''Terminonatator'' (meaning "last swimmer") is a genus of elasmosaurid plesiosaur from the Late Cretaceous of Saskatchewan, Canada. It is known from a skull and partial skeleton from a young adult, found in the Campanian-age Bearpaw Formation ...

'' in 2003. On November 9, 2015, it was reported to the Royal Tyrrell Museum that some articulated vertebrae were discovered in conditions similar to those previously mentioned, still near Lethbridge. Subsequently, more vertebrae were discovered by Korite workers, but due to the particularly difficult conditions in winter, the recovery of the fossils had to be done quickly. The fossils recovered consist of a partial skeleton preserving a

vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...

running from the base of the neck to the base of the tail, followed by a few articulated and disarticulated ribs. The discovery was made official the following year by Canadian paleontologist Darren H. Tanke via a summary, in which he referred this specimen as

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

''Albertonectes''.

Description

''Albertonectes'' has the longest neck of any

elasmosaur Elasmosauridae, often called elasmosaurs or elasmosaurids, is an extinct family (biology), family of plesiosaurs that lived from the Hauterivian Stage (stratigraphy), stage of the Early Cretaceous to the Maastrichtian stage of the Late Cretaceou ...

ever discovered, which reached up to . The holotype, missing the skull, measures at from the atlas-axis complex to the tip of the tail, suggesting a total body length of with the skull. In 2024, Henderson estimated its total body length up to and its total body mass around . ''Albertonectes'' is also unique among other

s in having 76 neck vertebrae, a record number among elasmosaurids (and vertebrates as a whole). ''Callawayasaurus'' with a similar count of 56 lacks the dumbbell-shaped articular faces that are present on the vertebrae of ''Vegasaurus''. Additional traits rarely seen in other elasmosaurids include: a tapered front-side projection on the pubis that extends to the side beyond the

acetabulum The acetabulum (; : acetabula), also called the cotyloid cavity, is a wikt:concave, concave surface of the pelvis. The femur head, head of the femur meets with the pelvis at the acetabulum, forming the Hip#Articulation, hip joint. Structure The ...

, a longitudinal ridge on the side of most neck vertebrae up to cervical 69, a clavicular arch that is wider than the adjacent front edge of the

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

, the lack of pectoral and pelvic bar, a tip of the tail that is made of seven fused tail vertebrae, and a slender

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 ...

with a width-to-length ratio of 0.56, among other traits. ''Albertonectes'' is known from a mature individual, as suggested by the fused

neural spine Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

s and most cervical ribs to their centra, and by the only partial connection between the

trochanter A trochanter is a tubercle of the femur near its joint with the hip bone. In humans and most mammals, the trochanters serve as important muscle attachment sites. Humans have two, sometimes three, trochanters. Etymology The anatomical term ' ...

and the capitulum (head) of the

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

, seen in TMP 2007.011.0001. Other observation also support an adult age, e.g. rough and wrinkled vertebral surfaces as well as well-developed facets and articulations on its

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

and

ankle The ankle, the talocrural region or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The ...

bones.

Gastroliths

The single known specimen of ''Albertonectes'' preserves

gastroliths A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In oth ...

, 97 of which are exposed and visible. These poked out of the dorsal side of the body between the ribs, as the animal had come to lie down on the seabed on its back some time after death, the gastroliths moving into the present position through gravity as the body decayed. The largest of the visible gastroliths weighed an estimated 1.13 kg. Gastroliths were generally either disc-shaped or spherical; the former would've come from beaches and the latter from river mouths. All were composed of

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

, as is the case with several other species of plesiosaurs. It is hypothesized that chert stones are specifically sought out by plesiosaurs as gastroliths for their hardness and durability.

Classification

Kubo ''et al.'' (2012) tested the

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 ...

position of ''Albertonectes'' using a highly modified version of Sato (2002)'s data-set, however its position wasn't stable and many

s formed rather large polytomies. This analysis was modified by O’Gorman ''et al.'' (2015), and the

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 ...

below follows their results, showing only the relationships within Elasmosauridae. Cladogram (2025):O'Keefe, F. Robin; Armour Smith, Elliott; Clark, Robert O.; Otero, Rodrigo A.; Perella, Anna; Trask, Patrick (2025-05-22). "A name for the Provincial Fossil of British Columbia: a strange new elasmosaur taxon from the Santonian of Vancouver Island". Journal of Systematic Palaeontology. 23 (1). doi:10.1080/14772019.2025.2489938. ISSN 1477-2019

References

{{Taxonbar, from=Q149959 Fossil taxa described in 2012 Elasmosauridae Late Cretaceous plesiosaurs of North America Sauropterygian genera Paleontology in Alberta

Discovery and naming

Description

Gastroliths

Classification

See also

References