Topic
Docodon
About: Docodon is a research topic. Over the lifetime, 4 publications have been published within this topic receiving 91 citations.
Papers
1 Jan 2010
TL;DR: A new phylogenetic analysis demonstrated that Itatodon is the most basal known docodontan and the evolutionary events which led to formation of the principal groups of Mesozoic mammals should have occurred sometime between the Sinemurian and Bajocian in Laurasia.
Abstract: T wo new docodontans, Simpsonodon sibiricus sp. nov. and Hutegotherium yaomingi gen. et sp. nov., and a new specimen of Itatodon tatarinovi Lopatin et Averianov, 2005 are described from the Middle Jurassic (Bathonian) Itat Formation of Krasnoyarsk Territory in West Siberia, Russia. A new phylogenetic analysis, incorporating 37 dental and mandibular characters and 18 docodontan and outgroup taxa demonstrated that Itatodon is the most basal known docodontan. Other docodontans can be classified in Docodontidae (Docodon and Haldanodon, with Borealestes recognized as a stem docodontid), Simpsonodontidae fam. nov. (Simpsonodon and Dsungarodon), Tegotheriidae (Krusatodon, Hutegotherium gen. nov., Tegotherium, and Sibirotherium), and Docodonta incertae sedis (Castorocauda, Tashkumyrodon, and Acuoduolodon). Simpsonodontidae fam. nov. is characterized, in particular, by a strongly developed additional groove dorsal to the Meckelian groove. The Middle Jurassic mammals of Laurasia are now known from three principal assemblages: Forest Marble in England, Balabansai in Kyrgyzstan, and Itat in West Siberia. All these three assemblages are very similar and comprise docodontans, allotherians, eutriconodontans, “symmetrodontans,” dryolestidans, and stem zatherians. The Middle Jurassic radiation of mammals has almost no roots in the known Early Jurassic mammal fauna and the evolutionary events which led to formation of the principal groups of Mesozoic mammals (Docodonta, Multituberculata, Eutriconodonta, Dryolestida, and stem Zatheria) should have occurred sometime between the Sinemurian and Bajocian in Laurasia, most probably in Asia (Siberia?).
44 citations
Journal Article•
TL;DR: In the early Late Jurassic (Oxfordian) Qigu Formation of the Junggar Basin in Northwest China (Xinjiang Au− tonomous Region) produced teeth and mandibular fragments of a new docodont.
Abstract: Fieldwork in the early Late Jurassic (Oxfordian) Qigu Formation of the Junggar Basin in Northwest China (Xinjiang Au− tonomous Region) produced teeth and mandibular fragments of a new docodont. The new taxon has a large “pseudo− talonid” on the lower molars, and by retention of crest b−g exhibits closer affinities to Simpsonodon and Krusatodon from the Middle Jurassic of Europe than to the other known Asian docodonts Tashkumyrodon, Tegotherium, and Sibirotherium. It differs from the Haldanodon–Docodon−lineage by the “pseudotalonid” and large cusps b and g. A PAUP analysis based on lower molar characters produced a single most parsimonious tree with two main clades. One clade comprises Docodon, Haldanodon, and Borealestes, and the other Dsungarodon, Simpsonodon, and Krusatodon plus the Asian tegotheriids. Analysis of the molar occlusal relationships using epoxy casts mounted on a micromanipulator revealed a four−phase chewing cycle with transverse component. The molars of the new docodont exhibit a well developed grinding function be− sides cutting and shearing, probably indicating an omnivorous or even herbivorous diet. A grinding and crushing function is also present in the molars of Simpsonodon, Krusatodon, and the Asian tegotheriids, whereas Borealestes, Haldanodon, and Docodon retain the plesiomorphic molar pattern with mainly piercing and cutting function.
41 citations
TL;DR: A phylogenetic analysis of 31 dental characters of docodonts (12 genera), plus six outgroups, supports a prior hypothesis that this group dispersed to Gondwana during the Middle Jurassic and hypothesizes that docodons and Late Triassic Tikitherium are sister taxa, and that the Tikitheringium-docodont clade, in turn, is related to the mammaliaforms Woutersia and Delsatia.
Abstract: Docodonts are a Mesozoic mammal group (Synapsida: Mammaliaformes) with a fossil record from the Middle Jurassic to the late Early Cretaceous. With highly distinctive molars for both shearing and grinding functions, docodonts are inferred to have diverse dietary adaptations, including insectivory, omnivory, and even carnivory. This group also offers the earliest-known case of mammalian swimming adaptation; at least two docodonts are inferred to have occupied a semi-aquatic niche. Here we present a phylogenetic analysis of 31 dental characters of docodonts (12 genera), plus six outgroups, including the taxa considered by some to be close relatives to docodonts. Our analysis recognizes a clade of Itatodon and Krusatodon and a clade of Tashkumyrodon and Borealestes, both of the Middle Jurassic. There is also a well-supported Late Jurassic Euroamerican clade (Dsungarodon, Docodon, and Haldanodon) and an Asiatic clade (Sibirotherium and Tegotherium). The Late Jurassic and Early Cretaceous clades are ne...
37 citations
21 Mar 2020
TL;DR: The Little Houston Quarry in the Black Hills of Wyoming contains the most diverse vertebrate fauna in the Morrison Formation (Upper Jurassic) north of Como Bluff and the second most diverse in the entire formation, after Reed's Quarry 9.
Abstract: The Little Houston Quarry in the Black Hills of Wyoming contains the most diverse vertebrate fauna in the Morrison Formation (Upper Jurassic) north of Como Bluff and the second-most diverse in the entire formation, after Reed’s Quarry 9. The deposit was an occasionally reactivated abandoned river channel, in interbedded green mudstone and laminated green-gray siltstone above a channel sandstone. The dinosaur material is densely distributed and is disarticulated to articulated, with several associated skeletons. The biota contains charophytes, horsetails, a possible seed fern, possible conifers, gastropods, two types of unionoid bivalves, diplostracans (“conchostracans”), a malacostracan, ray-finned fish, lungfish, a frog, salamanders, two types of turtles, rhynchocephalians, a lizard, choristoderes, two types of crocodyliforms, a pterosaur, Allosaurus and several types of small theropods including Tanycolagreus? and probable dromaeosaurids, numerous Camarasaurus and a diplodocine sauropod, a stegosaur, the neornithischian Nanosaurus, and the mammals Docodon, Amblotherium, and a multituberculate. Among these taxa, one of the unionoid bivalves, an atoposaurid crocodyliform, and the species of Amblotherium, which appear to be new and unique to the locality so far. The Docodon material may represent the first occurrence of D. apoxys outside of its type area in Colorado. Additionally, small, unusual theropod tooth types reported here may represent the first Late Jurassic occurrence of cf. Richardoestesia in North America and a possible abelisauroid, respectively.
2 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2010 | 1 |
| 2007 | 1 |
| 2005 | 1 |