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79-499: Doswellia is an extinct genus of archosauriform from the Late Triassic of North America. It is the most notable member of the family Doswelliidae , related to the proterochampsids . Doswellia was a low and heavily built carnivore which lived during the Carnian stage of the Late Triassic . It possesses many unusual features including a wide, flattened head with narrow jaws and

158-574: A dentary , and a femur ) were unearthed near Ashland , a little south of Doswell. These specimens were initially believed to have belonged to phytosaurs , but were recognized as pertaining to Doswellia after the Doswell specimens were found. The Ashland specimens are cataloged as USNM 186989 and USNM 244215. Assorted osteoderms and vertebrae from the Otis Chalk and Colorado City Formation in Texas , as well as

237-557: A species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in the nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

316-705: A box-like rib cage surrounded by many rows of bony plates. The type species Doswellia kaltenbachi was named in 1980 from fossils found within the Vinita member of the Doswell Formation (formerly known as the Falling Creek Formation ) in Virginia . The formation, which is found in the Taylorsville Basin , is part of the larger Newark Supergroup . Doswellia is named after Doswell , the town from which much of

395-478: A close relationship between Doswellia and the early archosauriform family Proterochampsidae . Desojo et al. (2011) added the South American archosauriforms Tarjadia and Archeopelta to Doswelliidae, and found support for Dilkes and Sues' classification in their own phylogenetic analysis. Although Tarjadia and Archeopelta are now considered to be erpetosuchids only distantly related to Doswellia ,

474-454: A diagonal ridge with two rows of teeth stretching along its underside. This is intermediate between proterochampsids (which have one row of teeth on their pterygoid ridge) and Doswellia (which has at least three). A different ridge along the inner edge of the pterygoid also hosts a longitudinal row of teeth. A few teeth are randomly distributed between the two ridges, though there were likely many more originally present. A possible palatine bone

553-401: A general skull anatomy convergent with some crocodyliforms , spinosaurids , and phytosaurs (particularly Smilosuchus ). However, its snout was somewhat less elongated than those other reptiles. The only known specimen of Rugarhynchos is NMMNH P-16909, a partial skeleton consisting of several bones scattered over a small area. The largest component is a mostly complete right side of

632-643: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

711-621: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

790-538: A massive purple mudstone layer of the lower Bluewater Creek Formation , also known as the Bluewater Creek Member of the Chinle Formation . Other fossils from Six Mile Canyon include fragments of aetosaurs , phytosaurs , and metoposaurids . The top of the Bluewater Creek Member was separated from overlying strata by a distinct tuffaceous sandstone layer (the "SMC bed") at Six Mile Canyon. The age of

869-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

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948-437: A related doswelliid. Once major anatomical differences were discovered, the species was given its own genus, Rugarhynchos , in 2020. Doswellia possesses many highly derived features in its skeleton. The skull is low and elongated with a narrow snout and wide temporal region behind the eye sockets. The temporal region is unusual in that it is euryapsid , which means that the lower of the two temporal holes on either side of

1027-416: A skull. It was originally described as pertaining to part of the snout, until further preparation revealed that it included most of the skull. Other cranial fragments include a right quadrate , left premaxilla , left maxillary fragments, and a partial right quadratojugal which was originally considered another maxillary fragment. A fragment originally described as an articulated parietal and postorbital

1106-478: A slightly younger date of 218.1 ± 0.7 Ma based on Chemical Abrasion–Thermal Ionization Mass Spectrometry (CA-TIMS) dating. These estimates suggest that the rocks which preserved Rugarhynchos were deposited in the vicinity of 220 Ma. The specimen was first described in 2012 as a new species of the armored archosauriform Doswellia . It was given the specific name Doswellia sixmilensis , in reference to its site of discovery. Its original describers noted that there

1185-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

1264-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

1343-614: A vertebra. The upper facets are termed diapophyses and connected to the upper rib head (tuberculum), while the lower facets are parapophyses and connected to the lower rib head (capitulum). No diapophyses are preserved, but large parapophyses were present close to the lower edge of the centrum. The capitulum and tuberculum of preserved ribs were closely set and cylindrical, as in Doswellia . The vertebrae were likely cervicals (neck vertebrae) due to having low-set parapophyses and prominent midline keels along their lower edge. Prominent excavations on

1422-457: Is Vancleavea . One autapomorphy (unique distinguishing feature) of Rugarhynchos is the presence of a thick diagonal ridge on the side of the snout. This ridge extends from the upper part of the maxilla onto the lacrimal, prefrontal, and frontal. Chanaresuchus and Proterochampsa have a similar ridge in front of the orbit, though it is less pronounced and does not extend onto the maxilla. Various smaller ridges and rough spots are present near

1501-418: Is also preserved. This bone has a crescent-shaped front half and a saddle-shaped rear half. This is similar to Proterochampsa and Chanaresuchus , though insufficient data on basal archosauriform palates prevents comparison to many other taxa. The only preserved jaw bone is a large surangular which is textured by rough longitudinal ridges. It is generally similar to that of Doswellia , though its upper edge

1580-596: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

1659-420: Is elongated and partially covered by a fused collection of bony scutes called a nuchal plate. The ribs in the front part of the torso project horizontally from the spine and then bend at nearly 90-degree angles to give the body of Doswellia a box-like shape. The blade-like ilium bone of the hip also projects horizontally. Rows of osteoderms stretched from the nuchal plate to the tail. At least ten rows covered

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1738-410: Is known to have preyed on terrestrial reptiles such as Malerisaurus . Other possible food sources include crustaceans , bivalves , and (most speculatively) large flying or hopping insects . It is also conceivable that it was capable of limited burrowing either for shelter (as in alligators ) or defense, partially burying itself to keep its armor exposed yet protect its soft underside. This technique

1817-704: Is not convex and its front tip is blunt and rounded. Unique to Rugarhynchos , there is a cup-shaped depression on the rear edge of the surangular below where it connects to the articular bone . Postcranial material of Rugarhynchos is sparse. Several fragmentary or complete centra (main vertebral components) were among the fossils recovered. These centra were low and wide, similar to other doswelliids, Vancleavea , and Litorosuchus , but unlike proterochampsids. Low, elliptical rib facets were located on short stalks. Other doswelliids had similarly shaped rib facets though set on longer stalks. Like most other reptiles, Rugarhynchos would have had two rib facets on either side of

1896-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

1975-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

2054-403: Is used by modern armadillos , echidnas and Cordylus lizards. The front limbs are unknown in Doswellia , so there is no direct evidence for burrowing adaptations. The neck of Doswellia was long and flexible, although also heavily armored, so it was likely incapable of bending above the horizontal, instead probably being used more for downwards and lateral (side-to-side) movement. The body

2133-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

2212-799: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

2291-678: The Monitor Butte Formation in Utah have also been assigned to Doswellia . Fossils referable to Doswellia cf. kaltenbachi are known from Petrified Forest National Park in Arizona . They were found in the Blue Mesa Member of the Chinle Formation , making the Arizona remains among the youngest in the genus. In 2012, a new species of archosauriform was described and referred to Doswellia , as

2370-704: The femur near the knee is the only fragment of the leg preserved in Rugarhynchos . Like other proterochampsians, this part of the femur was wide and had a subtle concavity on its front edge. The distal condyles were well-differentiated and both were slightly tapered. Although a pointed medial condyle is common to basal archosauriforms and pseudosuchians , a pointed lateral condyle is only observed in Gualosuchus among eucrocopodans . Many osteoderms (bony plates) have been preserved. They were roughly square-shaped and ornamented by large circular pits which radiated from

2449-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

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2528-469: The French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or the scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of

2607-452: The SMC bed has been estimated by several studies involving various Uranium-Lead dating techniques. A 2009 conference abstract argued that it was 219.3 ± 3.1 or 220.9 ± 0.6 million years old based on Laser Ablation– Inductively Coupled Plasma–Mass Spectrometry (LA-ICP-MS) and Isotope Dilution- Thermal Ionization Mass Spectrometry (ID-TIMS) dating techniques, respectively. A 2011 study instead found

2686-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

2765-406: The bizarre downward pointing hip could have given Doswellia an upright posture as in dinosaurs (including the armored ankylosaurs ), various other primitive features suggest that it was more likely to have been sprawling or semi-sprawling most of the time. In 2017, an osteoderm from the Doswellia holotype was given a histological analysis to study growth patterns. The analysis concluded that

2844-425: The body. The rest of the tail would have been more capable of bending downward, but lacked many adaptations for lateral movement. This means that, if Doswellia was an aquatic predator, it probably would not have used its tail for swimming as in modern crocodilians. Although limb material is not well known in Doswellia , material that is preserved suggests that both the front and rear legs were strongly built. Although

2923-409: The center of each plate, like other doswelliids. Also in line with doswelliids, the osteoderms articulate with each other via a smooth and flat front edge rather than spines or notches. However, several traits of Rugarhynchos 's osteoderms differ from other doswelliids. The pits are shallower and the upper surface of the osteoderm has a central blunt spike-like eminence rather than a raised keel. None of

3002-457: The construction of a sewage treatment plant in Doswell, Virginia . A party led by James Kaltenbach (the namesake of Doswellia kaltenbachi ) unearthed a large block containing a partial skeleton, including numerous vertebrae , ribs, osteoderms (bony plates), and other bones. This block, USNM 244214, has been designated the holotype of D. kaltenbachi . Two additional slabs were later unearthed at

3081-439: The fact that the ridges formed from the bone instead of the pits. In most prehistoric armored animals with pitted osteoderms, the pitting pattern formed due to specific spots of the bone being reabsorbed, creating pits. This even holds true to other doswelliids such as Jaxtasuchus . However, the studied osteoderm of Doswellia shows no evidence for reabsorption of specific areas, instead showing increased amounts of bone growth in

3160-469: The family Doswelliidae is still considered valid due to other taxa (such as Jaxtasuchus from Germany and Ankylosuchus from Texas) being considered close relatives of Doswellia . Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including

3239-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

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3318-424: The front half of the tooth row are covered by a convex extension, giving the maxilla a sigmoid lower edge akin to that of "robust-morph" phytosaurs. The maxillary teeth of Rugarhynchos had negligible curvature and were similar to the premaxillary teeth. The nasal is roughly textured, hosting a prominent ridge along the midline of the skull along with several other low ridges. The rear of the nasals are incised by

3397-727: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

3476-432: The idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but

3555-493: The large diagonal ridge of Rugarhynchos . These include a raised, bulbous rim of the orbit, a thin horizontal ridge on the prefrontal, and a thicker ridge along the prefrontal-frontal suture. The upper edge of the orbit also has a prominent raised boss formed by the frontal. Behind and below the orbit lies the very large and blocky jugal . It is textured by prominent bumps, ridges, and pits, though these features are less pronounced than those of Doswellia . The overlying squamosal

3634-628: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

3713-489: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. Rugarhynchos Rugarhynchos is an extinct genus of doswelliid archosauriform from the Late Triassic of New Mexico . The only known species is Rugarhynchos sixmilensis . It was originally described as a species of Doswellia in 2012, before receiving its own genus in 2020. Rugarhynchos

3792-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

3871-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

3950-419: The osteoderm formed by "intramembraneous ossification" due to the lack of structural fibers within it. This means that the bone of the osteoderm formed from a soft layer of periosteal tissue , rather than fibrous tendons or cartilage. Growth marks within the bone indicate that the holotype specimen of Doswellia died at 13 years of age. Perhaps the most unique aspect of Doswellia's osteoderm development lies in

4029-415: The osteoderms fossilized in articulation, so it is uncertain how they were arranged on the body. Nevertheless, Rugarhynchos likely had multiple longitudinal rows (columns) of osteoderms, as with other doswelliids. More irregularly shaped osteoderms near the skull may have connected to form a "nuchal shield" similar to that of Doswellia . To test its relations to other early archosauriforms, Rugarhynchos

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4108-526: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

4187-399: The rear edge of the squamosal and jugal. The lower part of the quadratojugal fits into a prominent notch on the jugal. Both of these traits are autapomorphies of Rugarhynchos. The quadrate is steeply angled to the rest of the skull (like Chanaresuchus and Doswellia ) and also has a large, hooked upper portion (like Vancleavea and allokotosaurians ). The middle of the pterygoid had

4266-437: The same site and almost certainly pertained to the same individual. One of these slabs contained additional vertebrae and ribs while the other contained a partial skull and mandible. These additional slabs were collectively termed the paratype , USNM 214823. An isolated right jugal found at the site (USNM 437574) was also referred to the species. In the 1950s and 1960s, several additional bones (including vertebrae, osteoderms,

4345-561: The second species Doswellia sixmilensis . The holotype of this species was NMMNH P-61909, an incomplete skeleton including skull fragments, osteoderms, vertebrae, and possible limb fragments. It was found in strata of the Bluewater Creek Formation exposed at Sixmile Canyon in McKinley County, New Mexico . A 2020 redescription of " Doswellia" sixmilensis determined that its supposed snout fragments represented an entire skull of

4424-403: The side of the vertebrae gave them an X-shaped cross-section when seen from above. The centra were rectangular from the side and would have connected with each other on an even level, indicating that the neck was straight. A thick, curved bone fragment likely represents the upper part of a hip bone such as the pubis or ischium , though its identity cannot be determined precisely. A portion of

4503-431: The skull and very deep rear part of the lower jaw likely housed muscles that could let the jaw both open and close with a high amount of force. This contrasts with modern crocodilians, which have a powerful bite but a much weaker ability to open their jaws. Nevertheless, the high amount of sculpturing in the skull of Doswellia is similar to the skulls of modern crocodilians. It is likely an adaptation to minimize stresses in

4582-404: The skull during a powerful bite. The pointed teeth, long snout, and upward-pointing eyes of Doswellia are support for the idea that it was an aquatic carnivore. In addition, its relatively compact osteoderms are also evidence for an aquatic lifestyle. However, it may not necessarily have been strictly aquatic, as these features are also found in animals such as Parasuchus , a phytosaur which

4661-413: The skull has closed. The jugal bone has expanded into the region the lower temporal opening would normally occupy. Paired squamosal bones extend beyond the skull's back margin to form small horn-like projections. The skull of Doswellia lacks several bones found in other archosauriforms, including the postfrontals , tabulars , and postparietals . The body of Doswellia is also distinctive. The neck

4740-417: The space it left behind. It would have been tightly connected to the jugal, squamosal, and frontal, leaving no space for an infratemporal fenestra . This gives Rugarhynchos a euryapsid skull akin to Doswellia . The rear edge of the skull is formed by the quadratojugal , which connects to the rest of the skull in several unique ways. The upper part of the quadratojugal edges a shallow concave area formed by

4819-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

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4898-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

4977-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

5056-549: The taxon's remains have been found. A second species, D. sixmilensis, was described in 2012 from the Bluewater Creek Formation of the Chinle Group in New Mexico ; however, this species was subsequently transferred to a separate doswelliid genus, Rugarhynchos . Bonafide Doswellia kaltenbachi fossils are also known from the Chinle Formation of Arizona. The most complete specimens of Doswellia were discovered in 1974 during

5135-535: The triangular front edge of the frontals , creating a wedge-shaped suture also seen in Proterochampsa . The prefrontal and lacrimal form the front edge of the orbit (eye socket) and connect to the maxilla. Like other proterochampsians, there is no contact between the lacrimal and nasal. More unusually, there is also no trace of an antorbital fenestra between the maxilla, nasal, and lacrimal. The only other early archosauriform known to lack an antorbital fenestra

5214-566: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

5293-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

5372-438: The web of ridges which surround the pits. Although certain " rauisuchians " (non- crocodylomorph paracrocodylomorph archosaurs) also have osteoderms which form from bone growth in specific areas, their osteoderms are relatively smooth rather than pitted. Vancleavea , a supposed relative of Doswellia which also had its osteoderms analyzed, differed from the genus in multiple ways. The type species , Doswellia kaltenbachi ,

5451-416: The widest part of Doswellia 's back. The quadratojugal and surangular bones (on the cranium and lower jaw, respectively) were both incorporated into the jaw joint, reinforcing the joint and preventing side-to-side or front-to back movement. As a result, the jaws of Doswellia would have been incapable of any notable form of movement other than vertical scissor-like snapping. In addition, the expanded back of

5530-487: Was a close relative of Doswellia and shared several features with it, such as the absence of an infratemporal fenestra and heavily textured skull bones. However, it could also be distinguished by many unique characteristics, such as a thick diagonal ridge on the side of the snout, blunt spikes on its osteoderms , and a complex suture between the quadratojugal , squamosal , and jugal . Non-metric multidimensional scaling and tooth morphology suggest that Rugarhynchos had

5609-424: Was also probably incapable of moving up and down to much of an extent due to the extensive and overlapping armor plating which characterizes the genus. The chest would have been much more likely to have flexed laterally (like most living reptiles and amphibians) while the animal was walking. The first few tail vertebrae were similar to the body vertebrae, so the front of the tail would probably have been held level with

5688-424: Was also simple in shape and textured by long ridges and depressions. Its front edge formed the rear rim of a supratemporal fenestra, a hole in the upper part of the skull behind the orbits. The rear part of the squamosal connected to the quadrate and had a triangular horn-like structure similar to that of Doswellia . The postorbital is missing in the fossil, but its position relative to other bones can be inferred by

5767-485: Was described by Weems in 1980. Weems placed Doswellia within Thecodontia , a group of archosaurs that traditionally included many Triassic archosaurs. He placed the genus within its own family, Doswelliidae , and suborder, Dosweliina. Parrish (1993) placed Doswellia among the most primitive of the crurotarsans , a group that includes crocodilians and their extinct relatives. More recently, Dilkes and Sues (2009) proposed

5846-442: Was itself sister to a clade comprising Vancleavea and Litorosuchus . All of these taxa cumulatively make up the group Proterochampsia . The bayesian analysis had a very similar result, but differed in one major way. Instead of having a clean break between proterochampsids and doswelliids, the bayesian analysis suggested that Proterochampsidae in its traditional form was paraphyletic rather than monophyletic. Proterochampsa

5925-518: Was later considered part of the palate . The only preserved portion of the jaw is a left surangular , although a large right pterygoid fragment was originally considered an articular . Postcranial remains include 13 osteoderms , several vertebral fragments, a few isolated rib fragments, the lower end of a left femur , and a possible pelvic fragment which was originally described as a calcaneum . These fossils were found at Six Mile Canyon in McKinley County, New Mexico . They were recovered from

6004-492: Was placed into its own genus. The genus name is derived from Latin words for "wrinkle" and "nose", in reference to the wide variety of rough ridges on its snout. The front of the premaxilla expands to the side, forming a bulbous structure similar to that of many phytosaurs . It possessed eight teeth, with the first four being much larger than the last four. Premaxillary teeth were conical and ornamented by longitudinal ridges, but lacked serrations or cutting edges. The tooth row

6083-483: Was placed into a phylogenetic analysis derived from an earlier study by Ezcurra et al . (2017). This analysis was run under both maximum parsimony and bayesian search protocols. The parsimony analysis placed Rugarhynchos as a doswelliid and the sister taxon to Doswellia . Doswelliids were the sister taxa to a monophyletic Proterochampsidae , and the Doswelliidae+Proterochampsidae clade

6162-589: Was relatively little overlap between Doswellia sixmilensis and Doswellia kaltenbachi (the original species of Doswellia ). They suggested that new material may lead to the two species being distinguished as two genera. Further preparation altered several interpretations of the specimen. The most notable of these was the discovery that the purported snout fragment was actually almost an entire skull. A 2020 study followed these new interpretations, describing how " Doswellia sixmilensis " had numerous unique features contrasting with Doswellia kaltenbachi . " D. sixmilensis "

6241-424: Was slightly downturned at an angle of 15-20 degrees. Unlike other proterochampsians , the nares (nostril holes) did not seem to be oriented upwards. The rear branch of the premaxilla wedges into an extensive suture between the nasal and maxilla . There were 20 teeth in the maxillary tooth row, significantly more than in the maxillae of proterochampsids but in line with other doswelliids . Four enlarged teeth in

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