PBDB Taxon

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Aristonectinae

Osteichthyes - Plesiosauria - Elasmosauridae

Taxonomy

Aristonectinae was named by Otero et al. (2012).

It was reranked as the subfamily Aristonectinae by O'Gorman (2015), O'Gorman (2016), O'Gorman (2016), O'Keefe et al. (2017), O'Gorman et al. (2019), O'Gorman et al. (2019), O'Gorman et al. (2021), Otero (2024), O’Keefe et al. (2025).

It was assigned to Elasmosauridae by Otero et al. (2012), Otero and O'Gorman (2013), O'Gorman et al. (2014), Otero et al. (2014), Benson and Druckenmiller (2014), O'Gorman et al. (2014), Araujo et al. (2015), O'Gorman (2015), Otero et al. (2015), Otero et al. (2015), O'Gorman et al. (2016), O'Gorman (2016), O'Gorman (2016), Otero et al. (2016), O'Keefe et al. (2017), O'Gorman et al. (2019), Otero and Soto-Acuña (2021), Otero (2024); and to Weddellonectia by O'Gorman et al. (2019), O'Gorman (2019), O'Gorman et al. (2021), O’Keefe et al. (2025).

Subtaxa

Alexandronectes, Aristonectes (syn. Turneria), Mauisaurus, Mauisaurus haasti, Morturneria, Tuarangisaurus cabazai, Wunyelfia

Synonyms

Mauisaurus haasti was named by Hector (1874). It is a 3D body fossil. Its type locality is Jed River (S62/175), which is in a Campanian carbonate siltstone in the Conway Formation of New Zealand.

It was recombined as Cimoliosaurus haasti by Lydekker (1889); it was recombined as Elasmosaurus haasti by Bogolubov (1911); it was considered a nomen dubium by Hiller et al. (2017).
Tuarangisaurus cabazai was named by Gasparini et al. (2003). Its type specimen is MML-PV5, a partial skeleton (17 dorsal vertebrae, 30 caudals, ribs and gastralia, incomplete anterior and posterior limbs, left coracoid and fragments of the right scapula, complete ischium), and it is a 3D body fossil. Its type locality is Trapalcó, locality C, which is in a Maastrichtian marine mudstone in the Jagüel Formation of Argentina.

It was considered a nomen dubium by Gasparini et al. (2007), O'Gorman et al. (2014).
Mauisaurus was named by Hector (1874) [Sepkoski's age data: K u K Maes]. Its type is Mauisaurus haastii.

It was synonymized subjectively with Cimoliosaurus by Lydekker (1889); it was considered a nomen dubium by Hiller et al. (2017).

It was assigned to Sauropterygia by Hector (1874); to Cryptoclididae by White (1940); to Plesiosauria by Sepkoski (2002); and to Elasmosauridae by Seeley (1892), Wegner (1914), Persson (1963), Welles and Gregg (1971), Wiffen and Moisley (1986), Carroll (1988), Hiller et al. (2005), Otero et al. (2010), Otero et al. (2012), Otero et al. (2015).

Synonymy list

Year	Name and author
1874	Mauisaurus Hector p. 334
1874	Mauisaurus haasti Hector p. 346
1889	Cimoliosaurus haasti Lydekker p. 215
1892	Mauisaurus Seeley p. 151
1911	Elasmosaurus haasti Bogolubov pp. 84, 355
1914	Mauisaurus Wegner p. 290
1940	Mauisaurus White p. 461
1962	Mauisaurus haasti Welles pp. 75-76
1963	Mauisaurus Persson p. 19
1963	Mauisaurus haasti Persson p. 19
1971	Mauisaurus Welles and Gregg p. 22
1971	Mauisaurus haasti Welles and Gregg p. 22
1986	Mauisaurus Wiffen and Moisley p. 221
1986	Mauisaurus haasti Wiffen and Moisley p. 221
1988	Mauisaurus Carroll
1991	Mauisaurus haasti Fordyce p. 1174
2002	Mauisaurus Sepkoski
2003	Tuarangisaurus cabazai Gasparini et al. p. 164 figs. 5-7
2005	Mauisaurus Hiller et al. p. 591 figs. 5-20
2006	Mauisaurus haasti Scanlon p. 283
2010	Mauisaurus Otero et al.
2012	Aristonectinae Otero et al.
2012	Mauisaurus Otero et al.
2013	Aristonectinae Otero and O'Gorman
2014	Aristonectinae Benson and Druckenmiller figs. 2-3
2014	Aristonectinae O'Gorman et al. p. 43
2014	Aristonectinae O'Gorman et al.
2014	Aristonectinae Otero et al.
2015	Aristonectinae Araujo et al. p. 94
2015	Aristonectinae O'Gorman p. 190
2015	Aristonectinae Otero et al. p. 3
2015	Mauisaurus Otero et al. p. 3
2015	Mauisaurus haasti Otero et al. p. 3
2015	Aristonectinae Otero et al. p. 178
2016	Aristonectinae O'Gorman p. 41
2016	Aristonectinae O'Gorman et al. p. 65
2016	Aristonectinae Otero et al.
2017	Aristonectinae O'Keefe et al.
2019	Aristonectinae O'Gorman
2019	Aristonectinae O'Gorman et al. p. 215
2019	Aristonectinae O'Gorman et al. p. 40
2021	Aristonectinae O'Gorman et al.
2021	Aristonectinae Otero and Soto-Acuña p. 7
2024	Aristonectinae Otero p. 4
2025	Aristonectinae O’Keefe et al. p. 8

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
class	Osteichthyes
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967

Rank	Name	Author
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()
suborder	Sauropterygia
order	Plesiosauria	de Blainville 1835
superfamily	Plesiosauroidea	Welles 1943
family	Elasmosauridae	Cope 1869
—	Weddellonectia
subfamily	Aristonectinae	()
subfamily	Aristonectinae	()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Subfm. †Aristonectinae Otero et al. 2012

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G. †Alexandronectes Otero et al. 2016

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†Alexandronectes zealandiensis Otero et al. 2016

G. †Aristonectes Cabrera 1941

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†Aristonectes parvidens Cabrera 1941

†Aristonectes quiriquinensis Otero et al. 2014

Invalid names: Turneria Chatterjee and Small 1989 [synonym]

G. †Morturneria Chatterjee and Creisler 1994

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†Morturneria seymourensis Chatterjee and Creisler 1994

Invalid names: Turneria seymourensis Chatterjee and Small 1989 [replaced]

G. †Wunyelfia Otero and Soto-Acuña 2021

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†Wunyelfia maulensis Otero and Soto-Acuña 2021

Invalid names: Mauisaurus Hector 1874 [nomen dubium], Mauisaurus haasti Hector 1874 [nomen dubium], Tuarangisaurus cabazai Gasparini et al. 2003 [nomen dubium]

Diagnosis

Reference	Diagnosis
R. A. Otero et al. 2012	Late Cretaceous elasmosaurid plesiosaurians with the following characters: skull length not reduced or drastically enlarged in comparison to the body length; moderately large neck; presence of more than 25 teeth in the maxillar
J. P. O'Gorman et al. 2019	Late Cretace ous elasmosaurid with the following combination of characters : relatively small teeth with seven or more teeth on each premaxilla; 36 or more teeth on each maxilla; 42 or more teeth on each dentary; short premaxilla in lateral view; cerv ical centra length shorter than or equal to height
F. R. O’Keefe et al. 2025	A monophyletic Aristonectinae is recovered by all trees from our phylogenetic analysis; the three characters supporting this node are the loss of a hypophyseal ridge on the atlas-axis complex (character 146, 1 ! 0), a reduction in the number of cervical vertebrae (character 152, 5! 4), and a reversal in atlas cup morphology to round from heart-shaped (character 287, 0! 1). We note that while our topology of aristonectines is almost identical to that of O’Gorman et al. (2024); the outgroup to the aristonectines remains Marambionectes, and the least derived ingroup taxon is Wunyelfia.

Measurements

No measurements are available

Composition:

hydroxyapatiteo

Environment:

marineo

Locomotion:

actively mobileo

Life habit:

aquatico

Depth habitat:

surfaceo

Diet:

carnivoreo

Reproduction:

viviparouso

Created:

2009-07-20 06:05:48

Modified:

2011-08-12 01:58:15

Source: o = order

Reference: Kiessling 2004

Age range: base of the Piripauan to the top of the Late/Upper Maastrichtian or 86.10000 to 66.00000 Ma

Collections (31 total)

Time interval	Ma	Country or state	Original ID and collection number
Piripauan	86.1 - 83.6	New Zealand	Mauisaurus haasti (83537)
Campanian	83.6 - 72.2	New Zealand (South Island)	Mauisaurus haasti (37089 232395 232397)
Late/Upper Campanian	83.6 - 72.2	Antarctica (James Ross Island)	Aristonectinae indet. (123285)
Middle Campanian	83.6 - 72.2	New Zealand (South Island)	Mauisaurus haasti (97812)
Campanian - Maastrichtian	83.6 - 66.0	Chile	Aristonectes sp., Aristonectinae indet. (190521)
Haumurian	83.6 - 66.0	New Zealand (Canterbury)	Elasmosauridae indet. (155319) Mauisaurus haastii (101408 101409)
Late/Upper Campanian - Early/Lower Maastrichtian	83.6 - 66.0	New Zealand (Hawke's Bay)	Mauisaurus haasti (232253)
Late/Upper Campanian - Maastrichtian	83.6 - 66.0	Argentina (Río Negro)	Plesiosauria indet. (51583)
Early/Lower Maastrichtian	72.2 - 66.0	Angola (Namibe)	Aristonectinae indet. (232402)
Late/Upper Maastrichtian	72.2 - 66.0	Antarctica	Aristonectes parvidens (140323) Aristonectes sp. (232357) Aristonectinae indet. (232334) Turneria seymourensis (13106)
Late/Upper Maastrichtian	72.2 - 66.0	Chile	Aristonectinae indet. (157301 221030) Aristonectinae indet., Mauisaurus sp. (91416)
Late/Upper Maastrichtian	72.2 - 66.0	New Zealand (South Island)	Mauisaurus haasti (232391 232392 232393 232401)
Late/Upper Maastrichtian	72.2 - 66.0	Chile (Puerto Natales)	Aristonectes sp. (208356) Aristonectinae indet. (208357 208358)
Late/Upper Maastrichtian	72.2 - 66.0	Chile (Biobio)	Aristonectes sp. (150921)
Late/Upper Maastrichtian	72.2 - 66.0	Chile (Concepción)	Aristonectes parvidens (118945)
Late/Upper Maastrichtian	72.2 - 66.0	Argentina (Chubut)	Aristonectes parvidens (97872)
Maastrichtian	72.2 - 66.0	Antarctica (Seymour Island)	Aristonectes sp. (63513)