Synonyms for hatcheri or Related words with hatcheri
Examples of "hatcheri"
The fossil "Ammodramus
" (Late Miocene of Kansas, United States) was formerly placed in genus "Palaeospiza" or "Palaeostruthus". The former may not be a passeriform at all, while the latter was eventually synonymized with "Ammodramus", as "A.
" scarcely differs from the living species.
The type species is "Nedoceratops
". "Nedoceratops" belonged to the Ceratopsia (the name is Greek for "horned faces", "Keratopia"), a group of herbivorous dinosaurs with parrot-like beaks which thrived in North America and Asia during the Cretaceous Period, which ended roughly 66 million years ago. All ceratopsians became extinct at the end of this era.
The Mylagaulidae or mylagaulids are a prehistoric family of sciuromorph rodents. They are known from the Neogene of North America and China. The oldest member is the Late Oligocene "Trilaccogaulus montanensis" from living some 29 million years ago (Mya), and the youngest was "Ceratogaulus
"—formerly in "Epigaulus"—which was found barely into the Pliocene, some 5 Mya.
Opinion has varied on the validity of a separate genus for "Nedoceratops". John Scannella and Jack Horner regarded it as an intermediate growth stage between "Triceratops" and "Torosaurus". Andrew Farke, in his 2011 redescription of the only known skull, concluded that it was an aged individual of its own valid taxon, "Nedoceratops
". Nicholas Longrich and Daniel Fields also did not consider it a transition between "Torosaurus" and "Triceratops", suggesting that the frill holes were pathological.
Since the "Diceratops" paper had been written by Hatcher, and Lull had only contributed the name and published the paper after Hatcher's death, Lull was not quite as convinced of the distinctiveness of "Diceratops", thinking it primarily pathological. By 1933, Lull had had second thoughts about "Diceratops" being a distinct genus and he put it in a subgenus of "Triceratops": "Triceratops" ("Diceratops") "
", including "T. obtusus"; largely attributing its differences to being that of an aged individual.
During Mesozoic and early Cenozoic times, Crocodylomorpha was far more diverse than it is now. Triassic forms were small, lightly built, active terrestrial animals. These were supplanted during the early Jurassic by various aquatic and marine forms. The Later Jurassic, Cretaceous, and Cenozoic saw a wide diversity of terrestrial and semi-aquatic lineages. "Modern" crocodilians do not appear until the Late Cretaceous. Among the largest crocodylomorphs are: the 7 metre long "Crocodylus anthropophagus", the 11 metre long "Sarcosuchus imperator", the 12 metre long "Deinosuchus
", and the 9 metre long "Machimosaurus hugii".
The paper that described "Nedoceratops" was originally part of O. C. Marsh's magnum opus, his Ceratopsidae monograph. Unfortunately, Marsh died (1899) before the work was completed, and John Bell Hatcher endeavored to complete the "Triceratops" section. However, he died of typhus in 1904 at the age of 42, leaving the paper still uncompleted. It fell to Richard Swann Lull to complete the monograph in 1905, publishing Hatcher's description of a skull separately and giving it the name "Diceratops
"; "Diceratops" means "two horned face."
These findings were contested a few years later by Catherine Forster, who reanalyzed "Triceratops" material more comprehensively and concluded that the remains fell into two species, "T. horridus" and "T. prorsus", although the distinctive skull of "T." (""Nedoceratops"") "
" differed enough to warrant a separate genus. She found that "T. horridus" and several other species belonged together, and "T. prorsus" and "T. brevicornus" stood alone, and since there were many more specimens in the first group, she suggested that this meant the two groups were two species. It is still possible to interpret the differences as representing a single species with sexual dimorphism.
In 1903, at Willow Creek, Montana, several fossil osteoderms were discovered "lying upon the surface of the soil" by John Bell Hatcher and T.W. Stanton. These osteoderms were initially attributed to the ankylosaurid dinosaur "Euoplocephalus". Excavation at the site, carried out by W.H. Utterback, yielded further fossils, including additional osteoderms, as well as vertebrae, ribs, and a pubis. When these specimens were examined, it became clear that they belonged to a large crocodilian and not a dinosaur; upon learning this, Hatcher "immediately lost interest" in the material. After Hatcher died in 1904, his colleague W.J. Holland studied and described the fossils. Holland assigned these specimens to a new genus and species, "Deinosuchus
", in 1909. "Deinosuchus" comes from the Greek δεινός/"deinos", meaning "terrible", and σοῦχος/"suchos", meaning "crocodile".
With time, the idea that the differing skulls might be representative of individual variation within one (or two) species gained popularity. In 1986, Ostrom and Wellnhofer published a paper in which they proposed that there was only one species, "Triceratops horridus". Part of their rationale was that generally there are only one or two species of any large animal in a region (modern examples being the elephant and the giraffe in modern Africa). To their findings, Lehman added the old Lull-Sternberg lineages combined with maturity and sexual dimorphism, suggesting that the "T. horridus"-"T. prorsus"-"T. brevicornus" lineage was composed of females, the "T.calicornis"-"T.elatus" lineage was made up of males, and the "T. obtusus"-"T.
" lineage was of pathologic old males. His reasoning was that males had taller, more erect horns and larger skulls, and females had smaller skulls with shorter, forward-facing horns.
In the first attempt to understand the many species, Lull found two groups, although he did not say how he distinguished them: one composed of "T. horridus", "T. prorsus", and "T. brevicornus"; the other of "T. elatus" and "T. calicornis". Two species ("T. serratus" and "T. flabellatus") stood apart from these groups. By 1933, and his revision of the landmark 1907 Hatcher-Marsh-Lull monograph of all known ceratopsians, he retained his two groups and two unaffiliated species, with a third lineage of "T. obtusus" and "T.
" that was characterized by a very small nasal horn. "T. horridus"-"T. prorsus"-"T. brevicornus" was now thought to be the most conservative lineage, with an increase in skull size and a decrease in nasal horn size, and "T. elatus"-"T. calicornis" was defined by large brow horns and small nasal horn. C. M. Sternberg made one modification, adding "T. eurycephalus" and suggesting that it linked the second and third lineages closer together than they were to the "T. horridus" lineage. This pattern was followed until the major studies of the 1980s and 1990s.
Scannella and Horner's conclusions have not been unanimously accepted. Several experts, though admitting the possibility that the "toromorph" hypothesis is correct, have denied this is probable. The hypothesis was directly challenged by a 2011 paper by Andrew Farke and a 2012 one by Nicholas Longrich. Farke in 2011 redescribed the problematic "Nedoceratops
" as an aged or diseased individual of its own genus, against Scannella and Horner who argued for its identification with "Triceratops". Farke pointed out that the irregular holes in the "Nedoceratops" frill, far from piercing thinning bone, were surrounded by thick swellings. Farke further concluded that several facts were difficult to reconcile with the proposed development of a "Triceratops" into a "Torosaurus". In general, with ceratopids the number of epoccipitals does not increase when the frill grows. Even though the number of episquamosals is often variable, there seems to be no relation with size, because sometimes juveniles already show the maximum number; apparently this is a matter of individual variation, not ontogeny. Likewise, with Ceratopia in general, the formation of holes in the frill is not related to age, even the youngest individuals often possessing the parietal "fenestrae". The thin bone areas on the frill of "Triceratops", the purported location of incipient holes, Farke explained as muscle attachment sites. There would be no consistent relation between holes and a granular bone structure. Many "Triceratops" specimens have frills with a deeply veined surface, indicating considerable age; the bone of their frills would have to be rejuvenated and then become granulated again in order for hole formation to begin, which Farke considered an unlikely sequence. Finally, Farke pointed out that specimen YPM 1831, despite its enormous size, was apparently not yet full-grown, as shown by its unfused sutures and smooth bone texture, and thus seemed to represent an authentic "Torosaurus" subadult.
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