{{Short description|Extinct clade of mammals}} {{Automatic taxobox | fossil_range = {{Fossil range|Late Cretaceous|Miocene|earliest=Berriasian}}<small>Possible Early Cretaceous record</small> | image = Necrolestes.svg | image_caption = Skull of ''Necrolestes'' | image2 = Peligrotherium.jpg | image2_caption = Life restoration and skull and jaws of ''Peligrotherium'' | taxon = Meridiolestida | authority = Rougier, 2011 | subdivision_ranks = Subgroups | subdivision = See text }} [[File:Cronopio.svg|left|thumb|Skull of ''Cronopio'']] '''Meridiolestida''' is an extinct clade of mammals known from the Cretaceous and Cenozoic of South America and possibly Antarctica. They represented the dominant group of mammals in South America during the Late Cretaceous.<ref>{{Citation|last=Defler|first=Thomas|title=Ancient Mammals of Gondwanan South America|date=2019|url=http://link.springer.com/10.1007/978-3-319-98449-0_2|work=History of Terrestrial Mammals in South America|series=Topics in Geobiology |volume=42|pages=29–44|place=Cham|publisher=Springer International Publishing|doi=10.1007/978-3-319-98449-0_2|isbn=978-3-319-98448-3|s2cid=134806427 |access-date=2022-01-15|url-access=subscription}}</ref> Meridiolestidans were morphologically diverse, containing both small insectivores such as the "sabretooth-squirrel" ''Cronopio,<ref name="Cronopio">{{cite journal |author=Guillermo W. Rougier |author2=Sebastián Apesteguía |author3=Leandro C. Gaetano |year=2011 |title=Highly specialized mammalian skulls from the Late Cretaceous of South America |journal=Nature |volume=479 |issue=7371 |pages=98–102 |bibcode=2011Natur.479...98R |doi=10.1038/nature10591 |pmid=22051679 |postscript=, |s2cid=4380850}} [https://web.archive.org/web/20181103094019/https://media.nature.com/full/nature-assets/nature/journal/v479/n7371/extref/nature10591-s1.pdf supplementary information].</ref>'' as well as the clade Mesungulatoidea/Mesungulatomorpha, which ranged in size from the shrew-sized ''Reigitherium'' to the dog-sized ''Peligrotherium.'' Mesungulatoideans had highly modified dentition with bunodont (low and rounded) teeth, and were likely herbivores/omnivores.<ref>{{Cite journal |last1=Harper |first1=Tony |last2=Adkins |first2=Caleb |last3=Rougier |first3=Guillermo |date=2022 |title=Reconstructed masticatory biomechanics of Peligrotherium tropicalis, a non-therian mammal from the Paleocene of Argentina |journal=Acta Palaeontologica Polonica |volume=67 |doi=10.4202/app.00912.2021 |s2cid=247881626 |issn=0567-7920|doi-access=free }}</ref> Meridiolestidans are generally classified within Cladotheria, more closely related to living marsupials and placental mammals (Theria) than to monotremes, barring one study recovering them as the sister taxa to spalacotheriid "symmetrodonts".<ref>{{cite journal |last1=Averianov |first1=Alexander O. |last2=Martin |first2=Thomas |last3=Lopatin |first3=Alexey V. |title=A new phylogeny for basal Trechnotheria and Cladotheria and affinities of South American endemic Late Cretaceous mammals |journal=Naturwissenschaften |date=2013 |volume=100 |issue=4 |pages=311–326 |doi=10.1007/s00114-013-1028-3|pmid=23494201 |bibcode=2013NW....100..311A |s2cid=18504005 }}</ref> However, more recent studies have stuck to the cladotherian interpretation.<ref>{{cite conference|last1=Martinelli |first1=Agustin |last2=Chornogubsky |first2=Laura |last3=Abello |first3=María |last4=I. Goin |first4=Francisco |last5=Reguero |first5=Marcelo |title=The first non-therian dryolestoid from Antarctica |date=2014 |doi=10.13140/2.1.2770.8805 |url=https://www.researchgate.net/publication/265293378|conference=2014 SCAR Open Science Conference|location=Auckland, New Zealand}}</ref><ref name="O'Meara2014">{{cite journal |last1=O’Meara |first1=Rachel N. |last2=Thompson |first2=Richard S. |title=Were There Miocene Meridiolestidans? Assessing the Phylogenetic Placement of ''Necrolestes patagonensis'' and the Presence of a 40 Million Year Meridiolestidan Ghost Lineage |journal=Journal of Mammalian Evolution |date=2014 |volume=21 |issue=3 |pages=271–284 |doi=10.1007/s10914-013-9252-3|s2cid=880380 }}</ref> Within Cladotheria, they have often been placed in a group called Dryolestoidea together with Dryolestida, a group of mammals primarily known from the Jurassic and Early Cretaceous of the Northern Hemisphere. However, some analyses have found this group to be paraphyletic, with the meridiolestidans being more or less closely related to therian mammals than dryolestidans are.<ref name="O'Meara2014" /><ref name="Lasseron2022">{{cite journal |last1=Lasseron |first1=Maxime |last2=Martin |first2=Thomas |last3=Allain |first3=Ronana |last4=Haddoumi |first4=Hamid |last5=Jalil |first5=Nour-Eddine |last6=Zouhri |first6=Samir |last7=Gheerbrant |first7=Emmanuel |title=An African Radiation of 'Dryolestoidea' (Donodontidae, Cladotheria) and its Significance for Mammalian Evolution |journal=Journal of Mammalian Evolution |date=2022 |volume=29 |issue=4 |pages=733–761 |doi=10.1007/s10914-022-09613-9|s2cid=249324444 |url=https://hal-mnhn.archives-ouvertes.fr/mnhn-03693015/file/Lasseron%20et%20al%202022_Donodontidae%20Ksar%20Metlili_d%C3%A9p%C3%B4t%20HAL.pdf }}</ref> Meridiolestidans differ from dryolestidans in the absence of a parastylar hook on the molariform teeth and the lack of a Meckelian groove.
''Lakotalestes'' from the Early Cretaceous of North America, originally identified as a dryolestid, was noted in one paper to have a tooth morphology closer to that of meridiolestidans.<ref name="Hercynodon">{{Cite journal |last1=Martin |first1=Thomas |last2=Averianov |first2=Alexander O. |last3=Schultz |first3=Julia A. |last4=Schwermann |first4=Achim H. |last5=Wings |first5=Oliver |year=2021 |title=A derived dryolestid mammal indicates possible insular endemism in the Late Jurassic of Germany |journal=The Science of Nature |volume=108 |issue=3 |article-number=23 |bibcode=2021SciNa.108...23M |doi=10.1007/s00114-021-01719-z |pmc=8126546 |pmid=33993371 |doi-access=free}}</ref> A possible meridiolestidan is known from a tooth fragment, now lost, found in the La Meseta Formation from the Eocene of the Antarctic Peninsula.<ref>{{Cite journal |last1=Gelfo |first1=Javier N. |last2=Goin |first2=Francisco J. |last3=Bauzá |first3=Nicolás |last4=Reguero |first4=Marcelo |date=30 September 2019 |title=The fossil record of Antarctic land mammals: Commented review and hypotheses for future research |url=http://www.aps-polar.org/paper/2019/30/03/A190814000002/full |journal=Advances in Polar Science |pages=274–292 |doi=10.13679/j.advps.2019.0021}}</ref> The latest surviving meridiolestidan was the mole-like burrowing insectivore ''Necrolestes'' from the Miocene of Patagonia.<ref name="O'Meara2014" />
==Taxa== * {{Extinct}}''Amarillodon''<ref name="Martine2022">{{cite journal |last1=Martin |first1=T. |last2=Goin |first2=F. J. |last3=Schultz |first3=J. A. |last4=Gelfo |first4=J. N. |title=Early Late Cretaceous mammals from southern Patagonia (Santa Cruz province, Argentina) |journal=Cretaceous Research |date=2022 |volume=133 |article-number=105127 |doi=10.1016/j.cretres.2021.105127|bibcode=2022CrRes.13305127M |s2cid=245549530 }}</ref> * {{Extinct}}''Austrotriconodon'' * {{Extinct}}''Bondesius''<ref name="Rougier2021a">{{cite book |last1=Rougier |first1=G. W. |last2=Martinelli |first2=A. G. |last3=Forasiepi |first3=A. M. |title=Mesozoic Mammals from South America and Their Forerunners |chapter=Dryolestoids |series=Springer Earth System Sciences |date=2021 |pages=201–260 |doi=10.1007/978-3-030-63862-7_6|isbn=978-3-030-63860-3 |s2cid=242314101 }}</ref> * {{Extinct}}''Casamiquelia''<ref name="Rougier2021a" /> * {{Extinct}}''Groebertherium''?<ref name="Connelly2024">{{cite journal |last1=Connelly |first1=B. E. |last2=Cardozo |first2=M. S. |last3=Montgomery |first3=J. D. |last4=Rougier |first4=G. W. |title=New mammals from the Upper Cretaceous Allen Formation (Patagonia, Argentina) and reassessment of meridiolestidan diversity. |journal=Cretaceous Research |date=2024 |volume=162 |article-number=105935 |doi=10.1016/j.cretres.2024.105935}}</ref> * {{Extinct}}''Lakotalestes''?<ref name=Hercynodon /> * {{Extinct}}''Paraungulatum''<ref name="Rougier2021a" /> * {{Extinct}}''Quirogatherium''<ref name="Rougier2021a" /> * {{Extinct}}''Solanutherium''<ref name="Connelly2024" /> * {{Extinct}}'''Cronopioidea?'''<ref name="Rougier2021a" /><ref name="Rougier2021b">{{cite journal |last1=Rougier |first1=G. W. |last2=Turazzinni |first2=G. F. |last3=Cardozo |first3=M. S. |last4=Harper |first4=T. |last5=Lires |first5=A. I. |last6=Canessa |first6=L. A. |title=New Specimens of ''Reigitherium bunodontum'' from the Late Cretaceous La Colonia Formation, Patagonia, Argentina and Meridiolestidan Diversity in South America |journal=Journal of Mammalian Evolution |date=2021 |volume=28 |issue=4 |pages=1051–1081 |doi=10.1007/s10914-021-09585-2|s2cid=254704047 }}</ref> ** {{Extinct}}''Cronopio'' ** {{Extinct}}''Leonardus''? ** {{Extinct}}''Necrolestes'' * {{Extinct}}'''Mesungulatoidea'''<ref name="Rougier2021b" /> ** {{Extinct}}''Peligrotherium'' ** {{Extinct}}''Coloniatherium'' ** {{Extinct}}''Mesungulatum'' ** {{Extinct}}''Orretherium'' ** '''{{Extinct}}Regitheriidae''' *** {{Extinct}}''Reigitherium'' *** ''{{Extinct}}Yeutherium''
Cladogram after Lasseron et al. 2022:<ref>{{Cite journal |last1=Lasseron |first1=Maxime |last2=Martin |first2=Thomas |last3=Allain |first3=Ronan |last4=Haddoumi |first4=Hamid |last5=Jalil |first5=Nour-Eddine |last6=Zouhri |first6=Samir |last7=Gheerbrant |first7=Emmanuel |date=December 2022 |title=An African Radiation of 'Dryolestoidea' (Donodontidae, Cladotheria) and its Significance for Mammalian Evolution |url=https://link.springer.com/10.1007/s10914-022-09613-9 |journal=Journal of Mammalian Evolution |language=en |volume=29 |issue=4 |pages=733–761 |doi=10.1007/s10914-022-09613-9 |issn=1064-7554}}</ref>{{Clade|{{Clade |label1=Meridiolestida |1={{Clade |1=''Cronopio'' |2={{Clade |1=''Necrolestes'' |2={{Clade |1=''Leonardus'' |label2=Mesungulatoidea |2={{Clade |1=''Reigitherium'' |2={{Clade |1=''Orretherium'' |2={{Clade |1=''Peligrotherium'' |2={{Clade |1=''Coloniatherium'' |2=''Mesungulatum'' }} }} }} }} }} }} }} |2={{Clade |1=Dryolestida |2={{Clade |1=Donodontidae |label2=Prototribosphenida |2={{Clade |1=''Vincelestes'' |2={{Clade |1=''Amphitherium'' |2={{Clade |1={{Clade |1=''Amphibetulimus'' |2=''Nanolestes'' }} |2={{Clade |1=''Palaeoxonodon'' |label2=Zatheria |2={{Clade |1={{Clade |1=''Arguimus'' |2=''Peramus'' }} |2=Tribosphenida }} }} }} }} }} }} }} }}|style=|label1=Cladotheria}}
==References== {{Reflist}}
{{Mammalia|H.}} {{Taxonbar|from=Q15991176}}
Category:Meridiolestida Category:Late Cretaceous first appearances Category:Miocene extinctions Category:Taxa named by Guillermo W. Rougier