Libonectes Morgani
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''Libonectes'' is an extinct genus of
sauropterygia Sauropterygia ("lizard flippers") is an extinct taxon of diverse, aquatic diapsid reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosau ...
n reptile belonging to the plesiosaur order. It is known from specimens found in the
Britton Formation The Britton Formation is a geologic formation deposited during the Middle Cenomanian to the Early Turonian ages of the Late Cretaceous in modern-day East Texas. It forms the lower half of the Eagle Ford Group in the northern portion of East Texa ...
of
Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
(USA) and the
Akrabou Formation The Akrabou Formation is a Late Cretaceous (latest Cenomanian to early/mid Turonian)-aged geological formation and Konservat-Lagerstätte in Morocco. It overlies the slightly older freshwater deposits of the Kem Kem Group, which it was once thought ...
of
Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...
, which have been dated to the lower
Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...
stage of the late
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
period.


Nomenclature

The
prefix A prefix is an affix which is placed before the stem of a word. Particularly in the study of languages, a prefix is also called a preformative, because it alters the form of the word to which it is affixed. Prefixes, like other affixes, can b ...
"''libo''" comes from
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 ...
(''lips''), and means "southern (wind)," translated to
English English usually refers to: * English language * English people English may also refer to: Culture, language and peoples * ''English'', an adjective for something of, from, or related to England * ''English'', an Amish ter ...
. "''Nectes''," the
suffix In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns and adjectives, and verb endings, which form the conjugation of verbs. Suffixes can ca ...
, is also from Greek (''nektes''), and translates to "swimmer." In its entirety, ''Libonectes'' can be interpreted as "southern swimmer." ''Libonectes'' was an elasmosaurid
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 ...
, with many specimens unearthed in southern parts of North America- as a result, it was labeled with such a name as described in the preceding sentence. Charles Gill Morgan is credited with the acquiring and preparation of the first ''Libonectes'' fossils, found by tenant farmer T.W. Tidwell in the late 1930s, and it was for this reason that ''morgani'' was chosen as the specific name part of its
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
.


Description

''Libonectes'' was a medium-sized plesiosaur, with the complete specimen (SMNK-PAL 3978) measuring long. The type specimen belonged to an individual with a neck measuring long. The animal was very similar to the related ''
Thalassomedon ''Thalassomedon'' (from Greek, ''thalassa'', "sea" and Greek, ''medon'', "lord" or "ruler", meaning "sea lord") is a genus of plesiosaur, named by Welles in 1943. Description ''Thalassomedon'' is among the largest elasmosaurids, with the holo ...
'', though the structure of the neck vertebrae was different, with taller neural spines and longer supporting processes of the bone, and its nostrils were slightly closer to the tip of the skull. The
type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...
of ''L. morgani'' contains the best preserved elasmosaurid skull known as well as
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. A shoulder girdle and flippers were also found but were apparently discarded at some point atter 1962,Carpenter, K. (1999). "Revision of North American elasmosaurs from the Cretaceous of the western interior." ''Paludicola'', 2(2): 148-173. along with the rear fourteen neck vertebrae of which only forty-eight remain. The specimen was originally named ''Elasmosaurus morgani'' by Welles in 1949, but it was reclassified to its own genus by Carpenter in 1997. A second species, ''L. atlasense'', was named in 2005 from deposits in
Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...
, but a 2017 redescription of the material recognized it as a junior synonym of ''L. morgani''.


Feeding Habits

The possible
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
nature of ''Libonectes'' is suggested by its dental layout, however, the presence of
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 ...
inside some known fossils feasibly indicates 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 ...
lifestyle (though
paleontological Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
investigation notes that plesiosaurs may have used gastroliths in buoyancy control). The presence of these gastroliths could also point to the possibility that ''Libonectes'' swallowed prey items whole. ''Libonectes'' most likely hunted in deep waters, perhaps eating small fish and
ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
, as it is thought that its bulk prevented the creature from frequenting shallow waters. This reptile is also suspected to have used its large size to trap prey, as a result of its slow swimming speed.


See also

*
List of plesiosaur genera This list of plesiosaurs is a comprehensive listing of all genera that have ever been included in the order Plesiosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered inv ...
*
Timeline of plesiosaur research This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, Taxonomy (biology), taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles ...


References


External links


Libonectes morgani
Sachs Vertebrate Palaeontology Research. Late Cretaceous plesiosaurs of North America Elasmosauridae Fossil taxa described in 1997 Taxa named by Kenneth Carpenter Sauropterygian genera {{plesiosaur-stub