{{Short description|Extinct genus of mammals}} {{Automatic taxobox | fossil_range = Early Miocene (Colhuehuapian-Santacrucian)<br />~{{fossil range|21.0|17.5}} | image = Necrolestes.svg | image_upright = 1.2 | image_caption = Skull of ''N. patagonensis'' | parent_authority = Ameghino, 1891<ref name=Ameghino>{{cite journal |author=Florentino Ameghino |year=1891 |title=Nuevos restos de mamíferos fósiles descubiertos por Carlos Ameghino en el Eoceno inferior de la Patagonia austral. Especies nuevas, adiciones y correciones |journal=Revista Argentina de Historia Natural |volume=1 |pages= 289–328|url=http://biostor.org/reference/111339 }}</ref> | taxon = Necrolestes | authority = Ameghino, 1891 | display_parents = 3 | type_species = ''Necrolestes patagonensis'' | type_species_authority = Ameghino, 1891 | subdivision_ranks = Species | subdivision = {{bold species list |{{extinct}}N. patagonensis|Ameghino, 1891 |{{extinct}}N. mirabilis|Goin ''et al.'', 2007}} }}
'''''Necrolestes''''' (from Ancient Greek νεκρός (''necrós''), meaning "dead", and λῃστής (''lēistḗs''), meaning "robber") is an extinct genus of mammals, which lived during the Early Miocene in what is now Argentine Patagonia. It is the most recent known genus of Meridiolestida, an extinct group of mammals more closely related to therians (marsupials and placentals) than to monotremes, which were the dominant mammals in South America during the Late Cretaceous. It contains two species, ''N. patagonensis'' and ''N. mirabilis''; the type species ''N. patagonensis'' was named by Florentino Ameghino in 1891 based on remains found by his brother, Carlos Ameghino in Patagonia. Fossils of ''Necrolestes'' have been found in the Sarmiento and Santa Cruz Formations.<ref name=FWNecrolestes>[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=40084 ''Necrolestes''] at Fossilworks.org</ref> Its morphology suggests that it was a digging, subterranean-dwelling mole-like mammal that fed on invertebrates.
== Description == thumb|right|230px|Lower jaw About one-third of the skeleton of ''N. patagonensis''—including most of the skull— has been found as disassociated bones of several individuals. The snout bends upwards at its end. The opening of the nasal fenestra has a septomaxilla separating the nasal and premaxilla bones, which is unknown in therian mammals, with the nasal fenestra also appearing to have ossified external nasal cartilage.<ref name=":0">{{Cite journal |last1=Wible |first1=John R. |last2=Rougier |first2=Guillermo W. |date=2017-06-15 |title=Craniomandibular Anatomy of the Subterranean Meridiolestidan Necrolestes patagonensis Ameghino, 1891 (Mammalia, Cladotheria) from the Early Miocene of Patagonia |url=http://www.bioone.org/doi/10.2992/007.084.0302 |journal=Annals of Carnegie Museum |language=en |volume=84 |issue=3 |pages=183–252 |doi=10.2992/007.084.0302 |issn=0097-4463|url-access=subscription }}</ref> The forelimbs have numerous characters in common with those of fossorial mammals, including a medially curved olecranon process of the ulna, and a mediolaterally compressed head of the humerus.<ref>{{Cite journal |last1=Asher |first1=Robert J. |last2=Horovitz |first2=Ine´S |last3=Martin |first3=Thomas |last4=Sánchez-Villagra |first4=Marcelo R. |date=2007 |title=Neither a Rodent nor a Platypus: a Reexamination of Necrolestes patagonensis Ameghino |url=http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1206%2F0003-0082(2007)3546%5B1%3ANARNAP%5D2.0.CO%3B2 |journal=American Museum Novitates |language=en |issue=3546 |pages=1 |doi=10.1206/0003-0082(2007)3546[1:NARNAP]2.0.CO;2 |issn=0003-0082}}</ref>
== Ecology == ''Necrolestes'' was probably a subterranean mole-like mammal that fed on invertebrates. The morphology of the snout suggests that it dug by lifting its snout upwards, similar to modern marsupial moles and golden moles, as well as by using its forelimbs. The high volume of the middle ear suggests that it had enhanced hearing of low-frequency sounds.<ref name=":0" />
== Classification == Its classification was historically unclear due to it being highly apomorphic and having an anatomy unlike any other known mammal, living or extinct. It was thought to be a therian mammal; placement within either the marsupial lineage (Metatheria) or as a member of Eutheria would have been possible given that South America as an island had extensive lineages of both marsupial and placental mammals. However, phylogenetic analyses conducted by Rougier ''et al.'' (2012), Chimento, Agnolin and Novas (2012) and Averianov, Martin and Lopatin (2013) recovered ''Necrolestes'' in an unexpected phylogenetic position as a nontherian mammal that belonged to the clade Meridiolestida;<ref name="PNAS">{{cite journal |author1=Guillermo W. Rougier |author2=John R. Wible |author3=Robin M. D. Beck |author4=Sebastian Apesteguía |year=2012 |title=The Miocene mammal ''Necrolestes'' demonstrates the survival of a Mesozoic nontherian lineage into the late Cenozoic of South America |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=109 |issue=49 |pages=20053–20058 |doi=10.1073/pnas.1212997109 |pmid=23169652 |pmc=3523863|bibcode=2012PNAS..10920053R |doi-access=free }}</ref><ref name="Chimentoetal">{{cite journal |author=Nicolás R. Chimento, Federico L. Agnolin and Fernando E. Novas |year=2012 |title=The Patagonian fossil mammal ''Necrolestes'': a Neogene survivor of Dryolestoidea |journal=Revista del Museo Argentino de Ciencias Naturales |series=Nueva Serie |volume=14 |issue=2 |pages=261–306 |url=http://www.macn.secyt.gov.ar/investigacion/descargas/publicaciones/revista/14/rns_vol14-2_261-306.pdf |access-date=2017-08-08 |archive-url=https://web.archive.org/web/20131104202302/http://www.macn.secyt.gov.ar/investigacion/descargas/publicaciones/revista/14/rns_vol14-2_261-306.pdf |archive-date=2013-11-04 |url-status=dead }}</ref><ref name="Averianovetal">{{cite journal |author1=Alexander O. Averianov |author2=Thomas Martin |author3=Alexey V. Lopatin |year=2013 |title=A new phylogeny for basal Trechnotheria and Cladotheria and affinities of South American endemic Late Cretaceous mammals |journal=Naturwissenschaften |volume=100 |issue=4 |pages=311–326 |doi=10.1007/s00114-013-1028-3 |pmid=23494201|bibcode=2013NW....100..311A |s2cid=18504005 }}</ref> if confirmed this would make ''Necrolestes'' the youngest known member of the group. Within Meridiolestida, Rougier ''et al.'' (2012) found ''Necrolestes'' to be particularly closely related to the genera ''Cronopio'' and ''Leonardus'';<ref name="PNAS" /> Chimento ''et al.'' (2012) found it to be in unresolved polytomy with ''Cronopio'', ''Leonardus'' and the clade containing all other meridiolestidans<ref name="Chimentoetal" /> while Averianov ''et al.'' (2013) recovered ''Cronopio'', ''Necrolestes'' and ''Leonardus'' as forming a grade at the base of Meridiolestida rather than a clade.<ref name="Averianovetal" /> A subsequent 2017 monograph of the skull anatomy further supported a placement within Meridiolestida.<ref name=":0" />
=== Phylogeny === This cladogram follows the paper of Rougier, Wible, Beck and Apesteguía of 2012:<ref name=PNAS/> {{Clade | style=font-size:100%;line-height:100% | label1='''Meridiolestida''' | 1={{Clade | 1={{Clade | 1=''Leonardus'' | 2={{Clade | 1=''Cronopio'' | 2='''''Necrolestes'''''}} }} | 2={{Clade | 1=''Reigitherium'' | 2={{Clade | 1=''Peligrotherium'' | 2={{Clade | 1=''Mesungulatum'' | 2=''Coloniatherium''}} }} }} }} }}
== References == {{Portal|Argentina|Paleontology|Prehistoric mammals}} {{Reflist}} {{Mammaliaformes|H.}} {{Taxonbar|from=Q75630}}
Category:Meridiolestida Category:Miocene mammals of South America Category:Santacrucian Category:Neogene Argentina Category:Fossils of Argentina Category:Fossil taxa described in 1891 Category:Taxa named by Florentino Ameghino Category:Prehistoric mammal genera Category:Golfo San Jorge Basin Category:Sarmiento Formation