{"id":869413,"date":"2026-10-03T13:46:26","date_gmt":"2026-10-03T13:46:26","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/869413\/"},"modified":"2026-10-03T13:46:26","modified_gmt":"2026-10-03T13:46:26","slug":"dinosaur-era-mammal-swam-like-platypus-and-replaced-its-teeth-multiple-times","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/869413\/","title":{"rendered":"Dinosaur-Era Mammal Swam Like Platypus and Replaced Its Teeth Multiple Times"},"content":{"rendered":"

Dongoconodon platycauda, a small eutriconodontan mammal that lived alongside dinosaurs in what is now northeastern China paddled through the water with webbed, platypus-like hands and feet, and replaced its teeth multiple times.<\/p>\n

\"An<\/a><\/p>\n

An artist\u2019s reconstruction of Dongoconodon platycauda. Image credit: Shi Yukun.<\/p>\n

Dongoconodon platycauda roamed our planet during the Early Cretaceous epoch, some 120 million years ago.<\/p>\n

The animal was roughly the size of a water vole and weighed an estimated 115 to 190 grams.<\/p>\n

It was a member of the Eutriconodonta<\/a>, an order of early mammals that lived during the Jurassic and Cretaceous periods.<\/p>\n

\u201cMammals originated through the progressive acquisition of key morphological and developmental innovations that underlie their evolutionary success across diverse ecological niches,\u201d said Yunnan University paleontologist Shundong Bi and colleagues.<\/p>\n

\u201cAmong these, diphyodonty (presence of two generations of teeth) and a fully detached middle ear are widely regarded as two key diagnostic features of living mammals and represent fundamental transitions in mammalian evolution.\u201d<\/p>\n

Dongoconodon platycauda is represented by a nearly complete articulated skeleton with a well-preserved skull and jaws.<\/p>\n

The fossil was collected in 2016 from the Changzigou locality of the Jiufotang Formation in China\u2019s Liaoning province.<\/p>\n

CT scans showed teeth in several stages of eruption and development, including replacement teeth beneath other replacements.<\/p>\n

According to the authors, the animal appears to have had three generations of teeth at some positions, across all four tooth types: incisors, canines, premolar-like teeth and molar-like teeth.<\/p>\n

Its close eutriconodontan relative, Gobiconodon borissiaki<\/a>, has been reported to replace some of its back teeth more than once.<\/p>\n

The researchers propose that this return to repeated tooth replacement is linked to a meat-eating lifestyle.<\/p>\n

\"Holotype<\/a><\/p>\n

Holotype specimen of Dongoconodon platycauda. Image credit: Bi et al., doi: 10.1038\/s41467-026-77339-w.<\/p>\n

\u201cDongoconodon has 11 tooth positions in the upper jaw and 10 in the mandible,\u201d the researchers said.<\/p>\n

\u201cTeeth are in different stages of eruption, and the replacement teeth are in different states of formation.\u201d<\/p>\n

\u201cThe most telling quadrant of the dentition for interpreting the replacement pattern in Donogoconodon is the right lower mandible.\u201d<\/p>\n

\u201cAnterior to the erupted canine are three unerupted teeth within the bone, a first incisor with its replacement followed by a second incisor.\u201d<\/p>\n

\u201cIn the postcanine dentition, the second and third molariforms are fully erupted.\u201d<\/p>\n

\u201cTo interpret this arrangement as a diphyodont dentition requires that these molariforms fully erupted before what would be two deciduous incisors, given that the first incisor has what would be a permanent replacement.\u201d<\/p>\n

\u201cSuch a pattern does not occur in any living or extinct mammals.\u201d<\/p>\n

Dongoconodon platycauda was also apparently a good swimmer.<\/p>\n

Its hands and feet resemble the platypus\u2019, with flattened, elongated bones.<\/p>\n

Small flanges on the finger bones match the places where webbing attaches in the platypus.<\/p>\n

Its tail vertebrae are flattened and box-like, similar to those of the nutria, a semiaquatic South American rodent with a lightly haired tail.<\/p>\n

The scientists conclude that the tail was used for steering and stability, while the forelimbs provided most of the propulsion.<\/p>\n

To test the swimming interpretation, they compared 13 limb-bone measurements of the fossil against 124 living species with known lifestyles. The fossil fell within the range of the semiaquatic species.<\/p>\n

\u201cThe new fossil shows adaptations for semiaquatic life, with hands and feet like the platypus that were similarly webbed,\u201d the authors concluded.<\/p>\n

\u201cIts unusual pattern of dorsoventrally flattened tail bones resembles the living nutria, a rodent native to South America.\u201d<\/p>\n

\u201cReappearance of polyphyodonty and molariform replacement in the new fossil and related gobiconodontids is probably associated with their ecomorphological niche and carnivorous diet.\u201d<\/p>\n

The discovery of Dongoconodon platycauda is described in a paper<\/a> published this week in the journal Nature Communications.<\/p>\n

_____<\/p>\n

S. Bi et al. 2026. A polyphyodont, semiaquatic eutriconodontan mammal from the Early Cretaceous of China. Nat Commun 17, 10032; doi: 10.1038\/s41467-026-77339-w<\/p>\n","protected":false},"excerpt":{"rendered":"Dongoconodon platycauda, a small eutriconodontan mammal that lived alongside dinosaurs in what is now northeastern China paddled through…\n","protected":false},"author":2,"featured_media":869414,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[144,54828,366524,366525,366526,5168,311178,63587,366527,79,290954,21317],"class_list":["post-869413","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-china","tag-cretaceous","tag-dongoconodon","tag-dongoconodon-platycauda","tag-eutriconodonta","tag-fossil","tag-jiufotang-formation","tag-mammal","tag-polyphyodonty","tag-science","tag-tail","tag-teeth"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/869413","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=869413"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/869413\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/869414"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=869413"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=869413"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=869413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}