Палеонтологичид 86-72 сая жилийн өмнө амьдарч байсан титанозаврын шинэ төрөл зүйлийг сүүлний хоёр ясанд үндэслэн шинжлэх ухаанд бүртгэлээ.
Уругвай мөрний орчмоос 1980-аад онд олдсон сүүлний хоёр сээр нурууны ясыг судлаачид “Mesetasaurus protector” хэмээн нэрлэжээ. Universidad de la República-ийн эрдэмтэн Матиас Сото Нуньес болон түүний багийнхан 2026 оны долдугаар сарын 8-нд “Ameghiniana” сэтгүүлд энэхүү судалгааг нийтэлсэн байна. Уг үлэг гүрвэл нь Цэрдийн галавын сүүлч үед Өмнөд Америкт өргөн тархсан титанозаврын Aeolosaurini бүлэгт хамаардаг аж.
Олдворуудыг Уругвайн хойд хэсэгт орших Пайсанду мужийн Месета де Артигас дахь Гуичоны тогтоцын улаан өнгөт элсэн чулуунаас олсон бөгөөд нэг бие махбодод хамаарах боломжтой гэж үзэж байна. Судлаачдын тэмдэглэснээр, FC-DPV 3740A болон FC-DPV 3740B гэж ангилсан эдгээр яс нь тус улсаас олдсон хамгийн сайн хадгалагдалттай сауропод үлэг гүрвэлийн яснуудын нэг юм.
Филогенетикийн өргөн хүрээтэй шинжилгээгээр “Mesetasaurus protector”-ийг Аргентины “Aeolosaurus rionegrinus” болон Бразилын “Arrudatitan maximus”-тай ойр төрлийн болохыг тогтоожээ. Титанозаврууд нь Цэрдийн галавын сүүлч үед Өмнөд Америкт хамгийн олон төрөл зүйлээрээ ялгарч байсан өвсөн тэжээлт үлэг гүрвэлүүд юм.
Энэхүү нээлт нь тухайн үед Уругвайн нутаг дэвсгэрт ганц бие биш, харин олон төрлийн аварга том үлэг гүрвэлүүд амьдарч байсныг баталж байна. “Mesetasaurus protector” нь “Udelartitan celeste” хэмээх өөр нэг титанозавраас ялгаатай, Уругвайд бүртгэгдсэн хоёр дахь сауропод юм. Судлаачдын үзэж буйгаар, Aeolosaurini бүлгийн үлэг гүрвэлийн сүүлний ясны онцлог бүтэц нь тэднийг биостратиграфийн судалгаанд ашиглах боломжтой чухал үзүүлэлт болгож байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Two well-preserved tail vertebrae unearthed near the Uruguay River in the 1980s have now been described as a new species of giant dinosaur. Named Mesetasaurus protector, it was an aeolosaurine titanosaur that lived in what is now Uruguay between 86 and 72 million years ago, in the Late Cretaceous.
The bones came out of the ground decades ago, but the paper describing them was published online on July 8, 2026, in the journal Ameghiniana. Dr. Matías Soto Núñez of the Universidad de la República and colleagues are behind the work.
The animal belongs to Aeolosaurini, a lineage of titanosaurian sauropods that flourished across South America during the final chapters of the Cretaceous. That context matters, because it shapes how the researchers read the find.
A Pair of Tailbones From the Guichón Formation
The two vertebrae were collected at the Meseta de Artigas site, in the Guichón Formation of northern Uruguay’s Paysandú department. They were found lying close together in a small exposure of reddish sandstone, which suggests they belonged to a single individual.
As noted in the study, the two fossils, catalogued as FC-DPV 3740A and FC-DPV 3740B, are notable for its condition. The paleontologists said:
“The specimens are among the best-preserved sauropod vertebrae known in Uruguay.”
Placing the Animal on the Family Tree
To find out where Mesetasaurus protector fit, the team compared it with dozens of other titanosaurs using a large phylogenetic data set. The analysis placed it deep within Aeolosaurini, alongside relatives such as Aeolosaurus rionegrinus from Argentina and Arrudatitan maximus from Brazil. Titanosaurs as a whole were a big deal. Soto Núñez and colleagues said that:
“Titanosaurians constituted the most abundant and diverse sauropod clade during the Late Cretaceous, with several dozen genera recognized, particularly in South America.”
The group was already present by the Valanginian (137 to 132 million years ago) and reached enormous body sizes during the Albian-Cenomanian (113 to 94 million years ago). Titanosaurs were also the only sauropods to persist until the end of the Cretaceous, 67 million years ago.
Several lineages thrived in South America, among them Andesauroidea, Diamantinasauria, Saltasauridae, Lognkosauria and Rinconsauria, plus Aeolosaurini itself. The authors describe that last clade as “an endemic component of South American latest Cretaceous faunas.”
Uruguay’s Hidden Past
The discovery indicates that multiple lineages of giant herbivorous dinosaurs inhabited what is now Uruguay during the Late Cretaceous, rather than a single isolated population. Part of the evidence is a comparison with a sauropod already known from the country. According to the researchers:
“Mesetasaurus protector is the second sauropod species from Uruguay, belonging to a different titanosaur lineage than the saltasauroid Udelartitan celeste.”
It is also the second record of Aeolosaurini in the country. The first is a caudal vertebra from the latest Cretaceous Asencio Formation, referred to Aeolosaurus.
One more detail is easy to overlook, because the particular morphology of aeolosaurine tail vertebrae, the authors say, makes them “easily recognizable and could lead them to be used as a biostratigraphic proxy.”
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