| Martinectes | |
|---|---|
 | |
| Skeleton mount,University of Michigan Museum of Natural History | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | †Sauropterygia |
| Order: | †Plesiosauria |
| Family: | †Polycotylidae |
| Subfamily: | †Polycotylinae |
| Clade: | †Dolichorhynchia |
| Genus: | †Martinectes Clark, O'Keefe & Slack,2023 |
| Type species | |
| †Martinectes bonneri Adams,1997 | |
| Synonyms | |
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Martinectes is anextinct genus ofpolycotylid plesiosaur from theLate CretaceousSharon Springs Formation of the United States. The genus contains asingle speciesM. bonneri, known from multiple skeletons and skulls.Martinectes was historically considered to represent a species of the genusTrinacromerum and laterDolichorhynchops before it was moved to its own genus.[1] It was a large polycotylid measuring around 6–7 metres (20–23 ft) long.
Two very large specimens of a polycotylid plesiosaur (KUVP 40001 and 40002[2]) 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 ofTrinacromerum (T. bonneri). The specific name honoured University of Kansas preparator Orville Bonner.[3] Unknown to her at the time, Carpenter (1996) had revised the Polycotylidae and separatedDolichorhynchops fromTrinacromerum, raising the question as to whether or not the specimens represented a separate species or just larger individuals ofD. osborni. A study in 2008 found thatT. bonneri is a valid species ofDolichorhynchops,D. bonneri.[4] Carpenter (1996) estimated that KUVP 40001, with a skull measuring 98 centimetres (3.22 ft) long, had a total body length of more than approximately 5.1 metres (17 ft).[5] Everhart (2017) suggested that KUVP 40001 would have measured up to 6–7 metres (20–23 ft) in length.[6] A 2023 study assignsD. bonneri to a new genus,Martinectes; the name means "Martin's swimmer".[1]
Clark, O'Keefe & Slack (2023) recoveredMartinectes as apolycotylid member of the plesiosaur cladeLeptocleidia, as thesister taxon to an unnamed polycotyline from theNiobrara Formation. This clade, in turn, is sister toUnktaheela. These species, together withDolichorhynchops spp. (D. osborni andD. herschelensis), form the cladeDolichorhynchia within thePolycotylinae. The results of theirphylogenetic analyses are shown in thecladogram below:[1]
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