Sunnyodon is a tiny, extinct mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

, probably of the Lower Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

. It was a relatively early member of the also extinct order of Multituberculata

Multituberculata

The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

. It lived in obscurity in southern England during the "age of the dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s". It's within the suborder "Plagiaulacida

Plagiaulacida

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs"...

" and family Paulchoffatiidae

Paulchoffatiidae

Paulchoffatiidae is a family of extinct mammals that lived predominantly during the Upper Jurassic period, though a couple of genera are known from the earliest Cretaceous. Some undescribed fossils from the Middle Jurassic of England may represent earlier versions. Remains have been reported from...

.

The genus Sunnyodon ("Sunny tooth", after Sunnydown Farm) was named by Kielan-Jaworowska Z. and Ensom P.C. in 1992 based on a single species.

Fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 remains of the species Sunnyodon notleyi were found in the Upper Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 or Lower Cretaceous-age strata

Stratum

In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...

 of the Purbeck

Purbeck

Purbeck is a local government district in Dorset, England. The district is named after the Isle of Purbeck, a peninsula that forms a large proportion of the district's area. However the district extends significantly further north and west than the traditional boundary of the Isle of Purbeck along...

 Formation in Durlston Bay

Durlston Bay

Durlston Bay is a small bay next to a country park of the same name, just south of the resort of Swanage, on the Isle of Purbeck in Dorset, England...

, Dorset

Dorset

Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...

, England. This is a tooth-based species. According to P.C. Ensom, this Formation is now considered to be early Lower Cretaceous.

Taxonomy

Subclass †Allotheria

Allotheria

Allotheria was a branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudinal rows of cusps...

 Marsh, 1880

• Order †Multituberculata Cope, 1884:
  • suborder †Plagiaulacida
    Plagiaulacida
    Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs"...
    
     Simpson 1925
    • Family †Paulchoffatiidae
      Paulchoffatiidae
      Paulchoffatiidae is a family of extinct mammals that lived predominantly during the Upper Jurassic period, though a couple of genera are known from the earliest Cretaceous. Some undescribed fossils from the Middle Jurassic of England may represent earlier versions. Remains have been reported from...
      
       Hahn, 1969
      • subfamily †Paulchoffatiinae Hahn, 1971
        • Genus †Paulchoffatia
          Paulchoffatia
          Paulchoffatia is a genus of extinct mammal of the Upper Jurassic - Lower Cretaceous. It was a relatively early member of the also extinct order Multituberculata, within the suborder "Plagiaulacida" and family Paulchoffatiidae. It lived in Europe during the "age of the dinosaurs."The genus...
          
           Kühne, 1961
          • Species †P. delgador Kühne, 1961
        • Genus †Pseudobolodon
          Pseudobolodon
          Pseudobolodon was a relatively early member of the also extinct order of mammals, Multituberculata. It lived in Portugal during the Upper Jurassic, part of the "age of the dinosaurs." It lies within the suborder "Plagiaulacida" and family Paulchoffatiidae....
          
           Hahn, 1977
          • Species †P. oreas Hahn, 1977
          • Species †P. krebsi Hahn & Hahn, 1994
        • Genus †Henkelodon
          Henkelodon
          Henkelodon was a small mammal of the Upper Jurassic. It was a relatively early member of the extinct order Multituberculata. Henkelodon was a European herbivore that lived during the "age of the dinosaurs". It lies within the suborder "Plagiaulacida" and family Paulchoffatiidae.The genus Henkelodon...
          
           Hahn, 1987
          • Species †H. naias Hahn, 1987
        • Genus †Guimarotodon
          Guimarotodon
          Guimarotodon is an extinct mammal of the Upper Jurassic. It was a relatively early member of the also extinct order of Multituberculata. It made its living nibbling plants as great big, and small, dinosaurs roamed the world. Guimarotodon Hahn G, 1969...
          
           Hahn, 1969
          • Species †G. leiriensis Hahn, 1969
        • Genus †Meketibolodon
          Meketibolodon
          Meketibolodon is a genus of extinct mammal from the Kimmeridgian Camadas de Guimarota of Guimarota, Portugal. It was a relatively early member of the also extinct order Multituberculata, suborder Plagiaulacida, family Paulchoffatiidae. The genus was named by Hahn G...
          
           (Hahn, 1978) Hahn, 1993
          • Species †M. robustus (Hahn, 1978) Hahn, 1993
        • Genus †Plesiochoffatia
          Plesiochoffatia
          Plesiochoffatia is an extinct mammal of the Upper Jurassic. It was a relatively early member of the also extinct order Multituberculata. It was a resident of Portugal during the "age of the dinosaurs." It's in the suborder "Plagiaulacida" and family Paulchoffatiidae.The genus Plesiochoffatia was...
          
           Hahn & Hahn, 1999
          • Species †P. thoas Hahn & Hahn, 1998
          • Species †P. peparethos Hahn & Hahn, 1998
          • Species †P. staphylos Hahn & Hahn, 1998
        • Genus †Xenachoffatia
          Xenachoffatia
          Xenachoffatia is a small Jurassic mammal from Portugal. It was a relatively early member of the also extinct order of Multituberculata. It lived during "the age of the dinosaurs" and belongs to the suborder Plagiaulacida, family Paulchoffatiidae....
          
           Hahn & Hahn, 1998
          • Species †X. oinopion Hahn & Hahn, 1998
        • Genus †Bathmochoffatia
          Bathmochoffatia
          Bathmochoffatia is an extinct mammal of the Upper Jurassic. It was a relatively early member of the also extinct order Multituberculata. It lived in Portugal at about the same time as the far more famous dinosaur, Allosaurus. It is in the suborder "Plagiaulacida", family Paulchoffatiidae. The genus...
          
           Hahn & Hahn, 1998
          • Species †B. hapax Hahn & Hahn, 1998
        • Genus †Kielanodon
          Kielanodon
          Kielanodon is an extinct mammal of the Portuguese Upper Jurassic. It was a relatively early member of the also extinct order of Multituberculata...
          
           Hahn, 1987
          • Species †K. hopsoni Hahn, 1987
        • Genus †Meketichoffatia
          Meketichoffatia
          Meketichoffatia was a small mammal from the Upper Jurassic of Portugal. It was a relatively early member of the extinct order Multituberculata. It lived at the same time as dinosaurs such as Allosaurus. It's within the suborder "Plagiaulacida" and family Paulchoffatiidae.The genus Meketichoffatia ...
          
           Hahn, 1993
          • Species †M. krausei Hahn, 1993
        • Genus †Galveodon
          Galveodon
          Galveodon is an extinct, Spanish mammal of the Lower Cretaceous. It was a relatively early representative of the also extinct order of Multituberculata. It lived during 'the age of the dinosaurs'...
          
           Hahn & Hahn, 1992
          • Species †G. nannothus Hahn & Hahn, 1992
        • Genus †Sunnyodon Kielan-Jaworowska & Ensom, 1992
          • Species †S. notleyi Kielan-Jaworowska & Ensom, 1992