Martinectes
{{Short description|Genus of polycotylid plesiosaurs}}
{{about|the plesiosaur genus|musical genre|Martinetes}}
{{Automatic taxobox
| fossil_range = Late Cretaceous (late Campanian), {{fossilrange|80.57|78.25}}
| image = Martinectes UMMNH.jpg
| image_caption = Skeleton mount, University of Michigan Museum of Natural History
| display_parents = 2
| taxon = Martinectes
| authority = Clark, O'Keefe & Slack, 2023
| type_species = {{extinct}}Martinectes bonneri
| type_species_authority = Adams, 1997
| synonyms = *Trinacromerum bonneri
{{small|(Adams, 1997)}}
- Dolichorhynchops bonneri
{{small|(O'Keefe, 2008)}}
}}
Martinectes is an extinct genus of polycotylid plesiosaur from the Late Cretaceous Sharon Springs Formation of the United States. The genus contains a single species M. bonneri, known from multiple skeletons and skulls. Martinectes was historically considered to represent a species of the genus Trinacromerum and later Dolichorhynchops before it was moved to its own genus.{{Cite journal |last1=Clark |first1=Robert O. |last2=O’Keefe |first2=F. Robin |last3=Slack |first3=Sara E. |date=2023-12-24 |title=A new genus of small polycotylid plesiosaur from the Upper Cretaceous of the Western Interior Seaway and a clarification of the genus Dolichorhynchops |url=https://www.sciencedirect.com/science/article/pii/S0195667123003403 |journal=Cretaceous Research |volume=157 |pages=105812 |doi=10.1016/j.cretres.2023.105812 |issn=0195-6671|url-access=subscription }} It was a large polycotylid measuring around {{convert|6|-|7|m|ft}} long.
History
File:Oby007f5.png and femur of specimen UNSM 50133]]
Two very large specimens of a polycotylid plesiosaur (KUVP 40001 and 40002{{cite web|url=http://www.oceansofkansas.com/Pliosaurs/KU40001/KU40001-4.jpg|title=Image: KU40001-4.jpg, (589 × 500 px)|publisher=oceansofkansas.com|access-date=2015-09-05}}) were collected from the Pierre Shale of Wyoming and later reported on by Adams in her 1997 Masters thesis, and in the same year, she officially described the specimens as a new species of Trinacromerum (T. bonneri). The specific name honoured University of Kansas preparator Orville Bonner.{{Cite journal
| last = Adams | first = D. A. | year = 1997
| title = Trinacromerum bonneri, new species, last and fastest pliosaur of the Western Interior Seaway
| journal = Texas Journal of Science | volume = 49 | issue = 3 | pages = 179–198
}} Unknown to her at the time, Carpenter (1996) had revised the Polycotylidae and separated Dolichorhynchops from Trinacromerum, raising the question as to whether or not the specimens represented a separate species or just larger individuals of D. osborni. A study in 2008 found that T. bonneri is a valid species of Dolichorhynchops, D. bonneri.{{cite journal | last1 = O'Keefe | first1 = F. R. | year = 2008 | title = Cranial anatomy and taxonomy of Dolichorhynchops bonneri new combination, a polycotylid (Sauropterygia: Plesiosauria) from the Pierre Shale of Wyoming and South Dakota | doi = 10.1671/0272-4634(2008)28[664:caatod]2.0.co;2 | journal = Journal of Vertebrate Paleontology | volume = 28 | issue = 3| pages = 664–676 | s2cid = 32099438 }} Carpenter (1996) estimated that KUVP 40001, with a skull measuring {{convert|98|cm|ft}} long, had a total body length of more than approximately {{convert|5.1|m|ft}}.{{Cite journal | last = Carpenter | first = K. | year = 1996 | title = A Review of short-necked plesiosaurs from the Cretaceous of the western interior, North America | journal = Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen | volume = 201 | issue = 2 | pages = 259–287 | doi = 10.1127/njgpa/201/1996/259 | bibcode = 1996NJGPA.201..259C | url = http://doc.rero.ch/record/15069/files/PAL_E2225.pdf }} Everhart (2017) suggested that KUVP 40001 would have measured up to {{convert|6|-|7|m|ft}} in length.{{cite book|last=Everhart|first= M. J.|year=2017|title=Oceans of Kansas - A Natural History of the Western Interior Sea|publisher=Indiana University Press|edition=2nd|isbn=978-0253026323}} A 2023 study assigns D. bonneri to a new genus, Martinectes; the name means "Martin's swimmer".
Classification
Clark, O'Keefe & Slack (2023) recovered Martinectes as a polycotylid member of the plesiosaur clade Leptocleidia, as the sister taxon to an unnamed polycotyline from the Niobrara Formation. This clade, in turn, is sister to Unktaheela. These species, together with Dolichorhynchops spp. (D. osborni and D. herschelensis), form the clade Dolichorhynchia within the Polycotylinae. The results of their phylogenetic analyses are shown in the cladogram below:
{{clade
|{{clade
|1=Brancasaurus
|2={{clade
|1=Vectocleidus
|label3=Polycotylidae
|3={{clade
|1=Edgarosaurus
|2={{clade
|2={{clade
|1={{clade
}}
|3={{clade
|1={{clade
|1=Manemergus
|2=Thililua
}}
|label3=Polycotylinae
|3={{clade
|1={{clade
}}
|3={{clade
|1=Scalamagnus
|2={{clade
|label2=Dolichorhynchia
|2={{clade
|1={{clade
|2=Dolichorhynchops herschelensis }}
|3={{clade
|1={{clade
|1=Martinectes
|2=ROM 29010 {{small|(Niobrara polycotyline)}}{{Cite journal |last1=Sato |first1=Tamaki |last2=Wu |first2=Xiao-Chun |last3=Tirabasso |first3=Alex |last4=Bloskie |first4=Paul |date=2011-03-17 |title=Braincase of a polycotylid plesiosaur (Reptilia: Sauropterygia) from the Upper Cretaceous of Manitoba, Canada |journal=Journal of Vertebrate Paleontology |language=en |volume=31 |issue=2 |pages=313–329 |doi=10.1080/02724634.2011.550358 |bibcode=2011JVPal..31..313S |issn=0272-4634}} }}
|3={{clade
|1=Unktaheela
}} }} }} }} }} }} }} }} }} }} }} }}|label1=Leptocleidia}}
References
{{Reflist}}
{{Plesiosauria|L.}}
{{Taxonbar|from=Q123991308}}
Category:Late Cretaceous plesiosaurs of North America