29-581: Hypsilophodontidae (or Hypsilophodontia ) is a traditionally used family of ornithopod dinosaurs , generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from the Middle Jurassic until the Late Cretaceous . This inclusive status was supported by some phylogenetic analyses from the 1990s and mid 2000s, although there have also been many finding that
58-521: A herd that was killed in a mass death event. The genus was named by Hans Virchow in 1919, as opposed to Josef Felix Pompeckj (1920), who is often incorrectly cited as naming the genus. Dysalotosaurus was a small, relatively basal iguanodontian ornithopod . It lacked the large thumb spikes found in later iguanodontians, and was more adapted for bipedalism than its larger relatives with its short front limbs and long, counter-balancing tail. Dysalotosaurus had powerful and long hind limbs, suggesting it
87-778: A hypsilophodont, but excluded it from the family Hypsilophodontidae. The phylogenetic hypothesis of Galton is shown below. Taxa considered hypsilophodontids are enclosed by green. Fabrosaurus -> Echinodon Heterodontosaurus Ankylosauria Stegosauria Hadrosauridae Iguanodon -> Tenontosaurus Ceratopsia Stenopelix -> Psittacosaurus Camptosaurus leedsi -> Dysalotosaurus -> Dryosaurus -> Wealden ornithopod Camptosaurus Yaverlandia -> Stegoceras -> Pachycephalosaurus Parksosaurus Laosaurus minimus Thescelosaurus In 1992 David Weishampel and Ronald Heinrich reviewed
116-554: A lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching a consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called
145-506: A life expectancy of roughly twenty years and lived in herds of mixed ages. Dysalotosaurus was a precocial dinosaur, which experienced sexual maturity at ten years, had an indeterminate growth pattern, and maximum growth rates comparable to a large kangaroo. In 2011 paleontologists Florian Witzmann and Oliver Hampe from the Museum für Naturkunde and colleagues discovered that deformations of some Dysalotosaurus bones were likely caused by
174-420: A single row of teeth , four pedal digits, and a rhomboid sternum . For several decades after its naming the family only included Hypsilophodon . In 1911 Karl von Zittel published a textbook on vertebrate classifications, in which he included multiple genera in "Hypsilophodontidae" ( sic for Hypsilophodontidae), including Hypsilophodon , Nanosaurus , Laosaurus and Dryosaurus . Zittel considered
203-637: A viral infection similar to Paget's disease of bone . This is the oldest evidence of viral infection known to science. The discovery of a hemivertebra (spinal malformation) in another specimen likely caused scoliosis and other pathologic effects on the animal during its life. This malformation occurs in almost every vertebrate clade, though this is the first known evidence of the condition in dinosaurs. Contemporary dinosaurs were Kentrosaurus , various sauropods including Giraffatitan and Dicraeosaurus , and large theropods including Megalosaurus and Ceratosaurus . Pterosaurs are also common in
232-652: Is a genus of herbivorous iguanodontian dinosaur . It was a dryosaurid iguanodontian, and its fossils have been found in late Kimmeridgian -age rocks ( Late Jurassic ) of the Tendaguru Formation of Lindi Region in Tanzania . The type and only species of the genus is D. lettowvorbecki . This species was named by Hans Virchow in 1919 in honor of the Imperial German Army Officer, Paul von Lettow-Vorbeck . For much of
261-499: Is commonly referred to as the "walnut family". The delineation of what constitutes a family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to
290-485: Is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family
319-473: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Dysalotosaurus Dysalotosaurus ("uncatchable lizard")
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#1732781181548348-428: The prepubis . Their resulting cladogram is reproduced below: Tenontosaurus Dryosaurus Camptosaurus Thescelosaurus Yandusaurus Othnielia Parksosaurus Hypsilophodon Zephyrosaurus Orodromeus The following cladogram of hypsilophodont relationships depicts the paraphyletic hypotheses; the "natural Hypsilophodontidae" hypothesis has been falling out of favor since
377-470: The 1915 description he determined that it shared far more features with Hypsilophodontidae. He reclassified Laosaurus , Nanosaurus and Dryosaurus in the family Laosauridae, leaving only Thescelosaurus and Hypsilophodon in Hypsilophodontidae. The characteristics of the family were also re-analysed, and Gilmore showed that the premaxilla actually had teeth, a characteristic of the family;
406-449: The 20th century the species was referred to the related and approximately contemporary genus Dryosaurus , but newer studies reject this synonymy. Thousands of Dysalotosaurus bones and bone fragments have been recovered from the Tendaguru Formation in Tanzania , Africa since 1909; the specimens described by Hans Virchow (1919) were discovered between 1909 and 1913. It has been suggested that all of these specimens were part of
435-399: The 3rd manus digit had 4 phalanges ; the femur was either shorter or longer than the tibia; and dorsal ribs had only a single articulation point. The first expansive analysis on the relationships of Hypsilophodontidae was that of Swinton in 1936 , during a redescription of Hypsilophodon from new specimens. The possible hypsilophodonts Geranosaurus and Stenopelix were removed from
464-555: The clade (then the subfamily Hypsilophodontinae), and considered to be intermediate basal ornithopods, as there were no features linking them to Hypsilophodon . Thescelosaurus was considered within the family, because of the large number of shared features, as well as Dysalotosaurus , from the Kimmeridgian of Tanzania . Laosaurus and Dryosaurus were not considered hypsilophodonts because of their lack of distinguishable features, as Swinton concluded that they were probably in
493-648: The family Laosauridae, intermediate between Hypsilophodontidae and Iguanodontidae , and were probably synonyms of each other as well. Charles M. Sternberg (1940) considered there to be multiple genera within the family, all sharing fully enamelled teeth, divided into two subfamilies , Hypsilophodontinae and Thescelosaurinae . Within Hypsilophodontinae–grouped by a longer scapula , thinner forelimb and femora shorter than tibiae–Sternberg included Hypsilophodon , Dysalotosaurus , and Parksosaurus (renaming of Thescelosaurus warreni ). Only Thescelosaurus
522-540: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and
551-699: The family is an unnatural grouping which should only include the type genus, Hypsilophodon , with the other genera being within clades like Thescelosauridae and Elasmaria . A 2014 analysis by Norman recovered a grouping of Hypsilophodon , Rhabdodontidae and Tenontosaurus , which he referred to as Hypsilophodontia . That clade is formally defined in the PhyloCode as "the smallest clade within Ornithopoda containing Hypsilophodon foxii and Tenontosaurus tilletti provided it does not include Iguanodon bernissartensis ". All other analyses from around
580-549: The family to unite all taxa that lacked premaxilla teeth, had a single row of maxilla teeth, neck vertebrae which have flat articulations or a flat front and round back, fused sacral vertebrae, a femur shorter than the tibia , 5 fingered manus' and 4 toed peds. Thescelosaurus was named in 1913 by Charles Gilmore , and its skeleton was described in detail by the same author in 1915. Gilmore had originally classified Thescelosaurus within Camptosauridae , but in
609-534: The inner ear, that Dysalotosaurus was not able to discern between high- and low-frequency sounds (like most herbivorous dinosaurs). However, it also had other adaptations that are commonly associated with derived hearing abilities, rendering its sensory capabilities unclear. In 2016, Gregory S. Paul estimated Dysalotosaurus ' length at 2.5 metres (8.2 ft), and its weight at 80 kilograms (180 lb). Various specimens of Dysalotosaurus are known, all representing animals that were not yet sexually mature at
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#1732781181548638-893: The mid-late 1990s. It is after Brown et al. (2013), the most recent analysis of hypsilophodonts. Ornithischia, Ornithopoda, and Iguanodontia were not designated in their result, and so are left out here. Additional ornithopods beyond Tenontosaurus are omitted. Dinosaurs traditionally described as hypsilophodonts are found from Agilisaurus or Hexinlusaurus to Hypsilophodon or Gasparinisaura . Heterodontosaurus Scutellosaurus Lesothosaurus Agilisaurus Hexinlusaurus Othnielosaurus TMP 2008.045.0002 Oryctodromeus Albertadromeus Orodromeus Zephyrosaurus Parksosaurus Changchunsaurus Haya Jeholosaurus Thescelosaurus assiniboiensis Thescelosaurus neglectus Hypsilophodon Gasparinisaura Family (biology) Family ( Latin : familia , pl. : familiae )
667-520: The same time have instead found these latter taxa to be within Iguanodontia . The family Hypsilophodontidae is formally defined in the PhyloCode by Daniel Madzia and colleagues in 2021 as "the largest clade containing Hypsilophodon foxii , but not Iguanodon bernissartensis and Rhabdodon priscus ". Hypsilophodontidae was named originally in 1882 by Louis Dollo , as a family to include Hypsilophodon and other small ornithopods with
696-575: The seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted
725-493: The systematics and phylogenetics of Hypsilophodontidae. Hypsilophodontidae was supported as a monophyletic clade that encompassed "thescelosaurids", Hypsilophodon and Yandusaurus . The family was diagnosed by the absence of ridges that end as denticles in teeth (reversed in Hypsilophodon ); presence of a single central ridge on dentary teeth; ossified sternal plates on torso ribs; and a straight and unexpanded shape of
754-484: The time of their deaths. Ontogenetic studies demonstrate typical aging trends, such as a lengthening of the snout and relative shrinking of the orbit . Differences in dentition as the animals aged also suggest a change from an omnivorous diet early in life to fully herbivorous feeding habits as an adult. This switch reflects the general evolutionary trend towards obligate herbivory among iguanodontians and other ornithopods. Dysalotosaurus also appears to have had
783-549: The use of this term solely within the book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,
812-709: Was included in Thescelosaurinae, as it had a tibia shorter than the femur. Peter M. Galton in 1972 re-studied the relationships of taxa within Ornithischia . Thescelosaurus was removed from Hypsilophodontidae because of its short limbs, meaning it was probably not cursorial , unlike all other hypsilophodonts. The presence of premaxilla teeth, once used to diagnose the group, was found to be present in unrelated taxa like Heterodontosaurus , Protoceratops and Silvisaurus . Galton made Hypsilophodontidae paraphyletic, as he considered Thescelosaurus to be
841-405: Was relatively cursorial compared to Iguanodon and other members of the clade. A recent comparative study based on bone cross-sectional geometry confirmed its bipedal locomotion with erect stance. Based on CT scans of the braincase, it is believed that Dysalotosaurus held its head dorsally (pointing straight forward) when not feeding. The same study also suggested, based on the morphology of
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