Fluvionectes

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Fluvionectes
Temporal range: Campanian
~76–75  Ma
O
S
D
C
P
T
J
K
Pg
N
Fluvionectes with gastroliths.png
Holotype with gastroliths
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Sauropterygia
Order: Plesiosauria
Family: Elasmosauridae
Genus: Fluvionectes
Campbell et al., 2021
Species:
F. sloanae
Binomial name
Fluvionectes sloanae
Campbell et al., 2021

Fluvionectes (meaning "river swimmer", from both Latin and Greek) is a genus of elasmosaurid plesiosaur found in the Dinosaur Park Formation in Alberta, Canada. [1]

Contents

Description

Quarry map (A) and reconstruction of the holotype (B). Quarry map and reconstruction of holotype of Fluvionectes.png
Quarry map (A) and reconstruction of the holotype (B).

The holotype specimen of Fluvionectes is a partial skeleton preserving an osteologically mature, likely a young adult individual that would have reached 5–5.2 m (16–17 ft) long and weighed 392 kilograms (864 lb). [1] [2] A more mature, larger, but more fragmentary specimen (TMP 2009.037.0007) is also known, consisting of a partial rib and gastralium, and left humerus, indicating that this taxon may have reached 7 m (23 ft) in maximum body length. A number of other fragmentary specimens are also known. [1]

The holotype skeleton had 76 gastroliths, largely disc-shaped stones. All were composed of black chert and grey quartzite, the largest of which weighed 15.3 grams. [1] [2]

Life restoration Fluvionectes sloanae.png
Life restoration

Classification

The describers placed Fluvionectes in Elasmosauridae, in a clade with Albertonectes , Nakonanectes , Styxosaurus , and Terminonatator , which by definition places it in the Elasmosaurinae subfamily. [1]

Palaeoecology

Fluvionectes appears to have been a freshwater and brackish water animal based on its discovery from a non-marine to paralic sedimentary unit. Both the holotype and the largest specimen (TMP 2009.037.0007) were found in brackish estuarine deposits, but a number of other specimens were found in nearby freshwater fluvial deposits. This is significantly different in contrast to most elasmosaurs which were oceanic. [1]

Other fossils associated with the holotype specimen included the turtle Kimurachelys slobodae and the rhinobatoid ray Myledaphus. Three dinoflagellates were also found, suggesting a marine influenced environment, although their low abundance and diversity suggests that it was not an open-marine environment. [1]

The holotype was discovered alongside many pieces of coalified wood, which is interpreted as the carcass having been caught in a log jam. [2]

Tooth of holotype of Fluvionectes sloanae.png
Holotype tooth
Select vertebrae of holotype of Fluvionectes sloanae.png
Holotype vertebrae.
Gastralia of holotype of Fluvionectes sloanae, gen. et sp. nov.png
Holotype gastralia
Representative ribs of holotype of Fluvionectes sloanae.png
Holotype ribs
Pectoral girdle of holotype of Fluvionectes sloanae.png
Holotype pectoral girdle
Forelimb (A-J) and hindlimb (K) elements of holotype of Fluvionectes sloanae.png
Holotype forelimb (A-J) and hindlimb (K)
Pelvic girdle of holotype of Fluvionectes sloanae.png
Holotype pelvic girdle
Skeletal elements of TMP 2009.037.0007, referred specimen of Fluvionectes sloanae.png
TMP 2009.037.0007
Vertebrae, pectoral and pelvic girdles, and humeri of Fluvionectes sloanae.png
Various specimens: vertebrae, pectoral and pelvic girdles, and humeri

References

  1. 1 2 3 4 5 6 7 Campbell, Mitchel, Ryan and Anderson, James A., Mark T., Michael J., Jason S. (2021). "A new elasmosaurid (Sauropterygia: Plesiosauria) from the non-marine to paralic Dinosaur Park Formation of southern Alberta, Canada". PeerJ. 9: e10720. doi: 10.7717/peerj.10720 . PMC   7882142 . PMID   33614274.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. 1 2 3 Henderson, Donald M. (2024-08-28). "Lost, hidden, broken, cut-estimating and interpreting the shapes and masses of damaged assemblages of plesiosaur gastroliths". PeerJ. 12: e17925. doi: 10.7717/peerj.17925 . ISSN   2167-8359. PMC   11373562 . PMID   39234235.