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60-457: Shuvosaurus (meaning "Shuvo [Chatterjee]'s lizard") is a genus of beaked, bipedal poposauroid pseudosuchian from the Late Triassic (early to middle Norian ) of western Texas . Despite superficially resembling a theropod dinosaur , especially the ostrich-like ornithomimids , it is instead more closely related to living crocodilians than to dinosaurs . Shuvosaurus is known by

120-420: A polytomy amongst coelophysoids, while their relationships were fully resolved when Shuvosaurus was excluded. A similar relationship was argued for in 2005 in the master's thesis of James Lehane, who specifically identified it as a close relative of " Syntarsus " (now known as Megapnosaurus ). Lehane later revised this classification when formally publishing his description of the skull in 2023, subsequent to

180-485: A 1995 monograph on Late Triassic tetrapods from the American Southwest, Robert Long and Philip Murry regarded this material as so "radically different" from Postosuchus that they identified it as a new taxon of gracile " rauisuchian " allied to poposaurids (i.e. Poposaurus ) which they named Chatterjeea elegans —named after Sankar Chatterjee and from Latin elegans for "very fine" or "beautiful". In

240-413: A bonebed containing the remains of at least nine partially articulated and associated skeletons alongside the skeleton of a Postosuchus , with a minimum total of 14 individuals indicated by the number of right partial femurs collected. Upon its description, Chatterjee tentatively interpreted Shuvosaurus as a Triassic member of Ornithomimosauria , a group of theropod dinosaurs otherwise known only from

300-407: 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 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

360-651: 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

420-494: A long ghost lineage and was consequently greeted with scepticism by other researchers (such as Halszka Osmólska in 1997). The Shuvosaurus skulls were found mixed in with postcranial remains of small pseudosuchians from the Post Quarry—all lacking heads—which Chatterjee had previously described as juveniles of the large predatory rauisuchid Postosuchus (of which the fossils were also associated with) in 1985. However, in

480-628: 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,

540-409: 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

600-427: 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. ;

660-455: 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

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720-459: A very derived ornithomimosaur and compared it favourably with ornithomimids, noting a particular resemblance to Dromiceiomimus and a similar braincase construction to that of Struthiomimus . Furthermore, he noted that two other Cretaceous ornithomimosaur families, Garudimimidae and Harpymimidae (each themselves monotypic), paradoxically possessed different plesiomorphic features of their own that were already derived and ornithomimid-like in

780-612: 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

840-460: 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,

900-474: 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

960-488: The Ancient Greek σαῦρος ( sauros ), meaning "lizard"). These fossils consisted of the partially disarticulated remains of three skulls and a partial lower jaw (the holotype TTU ( Texas Tech University )-P9280 and paratypes TTU-P9281 and TTU-P9282), as well as a partial atlas and fragmentary vertebra, scapula and an informally referred tibia . Of these postcranial bones only the atlas belongs to Shuvosaurus ,

1020-565: The Cretaceous , due to similar construction of the skull, including toothless jaws and large eye sockets. This is reflected in the species name, inexpectatus , for the unexpected nature of finding a toothless, ornithomimid-like skull in Late Triassic deposits. As with the contemporary purported avian Protoavis and Postosuchus , Chatterjee's proposed affinities of a Late Triassic Post Quarry taxon to Cretaceous coelurosaurs invoked

1080-621: 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

1140-824: 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;

1200-459: The Shuvosaurus skull and " Chatterjeea " postcrania was made clear and Shuvosaurus was conclusively reidentified as a "rauisuchian" pseudosuchian related to Poposaurus . This grouping of Poposaurus -like taxa was later defined as the clade Poposauroidea. Phylogenetic analyses since then consistently find Shuvosaurus and Effigia as sister taxa , and together with Sillosuchus make up

1260-771: The University of Poznań before moving to Warsaw and studying at the University of Warsaw , which she graduated from in 1955. Since then she worked at the Institute of Paleobiology of the Polish Academy of Sciences (PAN). Between 1983–1988, she served as the institute's director. She was a member of the Polish–Mongolian expeditions to the Gobi Desert (1963–1965 and 1967–1971) and she described many finds from these rocks, often with Teresa Maryańska . Among

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1320-419: 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 ,

1380-404: 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,

1440-410: The type and only species S. inexpectatus , and is closely related to the very similar Effigia within the clade Shuvosauridae . Shuvosaurus was originally described from a restored skull and very few fragmentary postcranial bones as a probable ornithomimosaur , or at least a very ornithomimosaur-like early theropod. The true pseudosuchian affinities of Shuvosaurus were only recognised after

1500-707: The Texas Tech University (such as Technosaurus and Postosuchus ). Although precise dating is lacking for much of the Dockum Group, including the Post Quarry, it has been correlated to the Adamanian teilzone , a local biostratigraphic unit in the southwestern United States—that has elsewhere been dated to the early to middle Norian stage of the Late Triassic, between 224–215 million years old. The fossils of Shuvosaurus were preserved in

1560-505: The Triassic Shuvosaurus . This further complicated the relationship of Shuvosaurus to other ornithomimosaurs. Although Chatterjee argued in favour of Shuvosaurus being an ornithomimosaur, he nonetheless recognised the alternative possibility that the similarities could have independently evolved in a Triassic theropod. However, he himself considered convergent evolution unlikely in this case based on his interpretation of

1620-476: The Whitaker Quarry at Ghost Ranch which combined a Shuvosaurus -like skull with Chatterjeea -like postcrania that they named Effigia in 2006. This discovery showed that Shuvosaurus is more closely related to crocodilians and other pseudosuchians than dinosaurs, and that similarities between it and ornithomimids are indeed the result of convergent evolution , while simultaneously demonstrating that

1680-442: 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

1740-591: The bodies of Chatterjeea almost certainly belong to Shuvosaurus and therefore that the two are synonymous. Indeed, Shuvosaurus and Effigia are so anatomically similar that in 2007 Spencer Lucas and colleagues proposed that the two genera were synonymous, tentatively subsuming Effigia into Shuvosaurus as the species Shuvosaurus okeeffeae , a proposal that has not been followed in subsequent research. Shuvosaurus itself would not be thoroughly re-examined for many years until late 2023 and early 2024 when two separate redescriptions were published independently. First,

1800-550: The broader group Ornithomimosauria and therein erected the monotypic family Shuvosauridae. This was in part based on the presence of at least two inferred primitively ancestral (i.e. plesiomorphic ) traits (no parasphenoid capsule and a smaller brain cavity) compared to Cretaceous ornithomimosaurs, as well as its general distinctiveness relative to them. Ceratosauria Carnosauria Shuvosaurus Troodontidae Dromaeosauridae Aves Notably, despite these traits and its much older age, Chatterjee regarded Shuvosaurus as

1860-515: The cranial material, differing from those of previous authors, including Lehane (2023). Many isolated shuvosaurid remains found in rocks of the southwestern US from throughout the Late Triassic have been referred to Shuvosaurus (including to Chatterjeea ), namely from elsewhere in the Dockum Group and the Chinle Formation to the west. However, these referrals have been questioned after the discovery of Effigia , as it shows that many of

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1920-619: The dinosaurs she described are: Her other work included discussions of the paleobiology of hadrosaurids , and co-editing the two editions of The Dinosauria . She is recognized for her work in the names of the Mongolian oviraptorid Citipati osmolskae , the Chinese dromaeosaurid Velociraptor osmolskae , the Mongolian dromaeosaurid Halszkaraptor escuilliei , the archosauriform reptile Osmolskina czatkowicensis , and

1980-429: The discovery of Effigia linked the skull of Shuvosaurus with similar poposauroid skeletal remains found in the same quarry. Fossils of Shuvosaurus were first discovered and collected in 1984 but were not described until 1993 by palaeontologist Sankar Chatterjee , after they were recognised in the late 1980s during preparation by his younger son Shuvo Chatterjee, for whom he named it after (combining "Shuvo" with

2040-466: The discovery of Effigia . In 2005 Thomas Lehman and Chatterjee briefly alluded to purported additional material that they claimed suggested Shuvosaurus was a theropod more derived than ceratosaurs . However, this report was never followed up on in literature, and when Shuvosaurus was redescribed in 2024 Chatterjee recognised Shuvosaurus as a poposauroid pseudosuchian closely related to Effigia . An affinity to pseudosuchians (or at least poposaurs)

2100-446: 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

2160-737: 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,

2220-439: The identity of Shuvosaurus and its proposed synonymy with Chatterjeea . Notable among them, Oliver Rauhut (1997, 2000, 2003) argued that Shuvosaurus was indeed a theropod and distinct from Chatterjeea , but that it was instead a specialised basal taxon convergent with ornithomimosaurs. In the early 2000s, Sterling Nesbitt and Mark Norell prepared previously unopened plaster-jackets of an unknown archosaur collected from

2280-633: 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,

2340-505: 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. Halszka Osm%C3%B3lska Halszka Osmólska (September 15, 1930 – March 31, 2008) was a Polish paleontologist who had specialized in Mongolian dinosaurs . She was born in 1930 in Poznań . In 1949, she began to study biology at Faculty of Biology and Earth Sciences of

2400-436: The morphological evidence that otherwise appeared distinctly ornithomimosaurian. Chatterjee supported his argument with an early cladistic analysis of theropods (modelled on the phylogeny of Gauthier, 1986) in which Shuvosaurus possessed almost the entire suite of derived cranial characteristics in ornithomimosaurs in the dataset and as such was recovered in that clade. However, this analysis notably only included theropods and

2460-403: 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

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2520-428: 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

2580-474: The others have since been reidentified as belonging to an azendohsaurid , an ornithodiran and a neotheropod dinosaur, respectively. The fossils were collected from the Post Quarry (a.k.a. the Miller Quarry) of the lower Cooper Canyon Formation ( Dockum Group ) near Post , Garza County, Texas , US, and was one of many new discoveries made at this quarry in the 1980s by Chatterjee and his team from

2640-541: 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

2700-840: The re-defined family and clade of Shuvosauridae deeply nested within Poposauroidea. Below is a simplified cladogram modified from Nesbitt (2011), highlighting the relationship of Shuvosaurus to other poposauroids. Such a cladogram reflects the interrelationships of Shuvosaurus and other included poposauroids in subsequent analyses of pseudosuchian relationships, for example, Smith et al. (2024). Qianosuchus Arizonasaurus Xilousuchus Hypselorhachis Ctenosauriscus Bromsgroveia Waldhaus Taxon Poposaurus gracilis H Poposaurus gracilis Y Lotosaurus Sillosuchus Shuvosaurus Effigia [REDACTED] [REDACTED] [REDACTED] [REDACTED] Genus The composition of

2760-470: 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 the French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or

2820-524: The same publication, however, they raised the possibility that Shuvosaurus and Chatterjeea were in fact the same animal, noting the close association of their remains, lack of any apparent ornithomimosaurian postcrania otherwise referrable to Shuvosaurus in the quarry, and that the available material for Shuvosaurus and the Chatterjeea did not overlap (one known by heads, the other skeletons). Following Long and Murry (1995), opinions were divided on

2880-408: 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 a species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in

2940-463: The skull was definitively even that of a dinosaur in the first place. Theropod dinosaur affinities for Shuvosaurus were nonetheless still supported by some researchers in the late 1990s and early 2000s, most notably by Oliver Rauhut. In 1997, Rauhut rejected Long and Murry's proposal Shuvosaurus was synonymous with Chatterjeea (and therefore a pseudosuchian) on the basis of theropod-like features of its skull that were unknown in any pseudosuchian at

3000-416: The skull was redescribed by Lehane (2023), based upon the work of his previously unpublished 2005 master's thesis , and was followed shortly after by a complete skeletal osteology from Nesbitt and Chatterjee (2024). Although both were published closely together, the work in each was conducted independently and published in parallel. Notably, Nesbitt and Chatterjee (2024) provide novel interpretations of some of

3060-497: 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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3120-412: 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

3180-403: 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

3240-439: The time (later shown to indeed be convergent by Effigia ), but did not identify it as an ornithomimosaur. Instead, he believed Shuvosaurus to be an early-diverging theropod, but could not confidently determine its relationships further due to its numerous derived traits. Rauhut later included Shuvosaurus in a phylogenetic analysis of theropods in 2003, in which it was recovered as a coelophysoid . However, its inclusion led to

3300-445: The traits used to assign material to Shuvosaurus are only diagnostic of Shuvosauridae as a whole. Following their osteological description, Nesbitt and Chatterjee revised the taxonomic diagnosis of Shuvosaurus in 2024 and in doing so restricted Shuvosaurus to the type and associated material of the Post Quarry bonebed alone, as isolated bones cannot be reliably differentiated between the two genera. Upon its description Shuvosaurus

3360-576: 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

3420-429: 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

3480-447: Was focused entirely on a set of 43 skull traits that characterised the already recognised theropod taxa. The affinity of Shuvosaurus to Ornithomimosauria was subsequently questioned by later researchers, such as Osmólska (1998). Hunt et al. (1998) and Heckert & Lucas (1998) went even further and argued that although Chatterjee (1993) compared specific features of Shuvosaurus strongly to ornithomimosaurs, he had not demonstrated that

3540-404: Was made correctly based on its postcrania from the start, first as juvenile Postosuchus by Chatterjee, and then as Chatterjeea by Long and Murry (1995). Long and Murry regarded the Chatterjeea postcrania as belonging to a highly derived "rauisuchian" derived from poposaurids that they classified under the new family Chatterjeeidae. With the discovery of Effigia in 2006 the association between

3600-455: Was tentatively classified as a member of the coelurosaurian theropod clade Ornithomimosauria based on superficial similarity of its reconstructed skull. In an early report of its discovery at the annual Society of Vertebrate Paleontology meeting in 1991 Chatterjee even explicitly referred Shuvosaurus to the derived ornithomimosaur family Ornithomimidae. However, in its formal printed description in 1993 he instead more cautiously referred it to

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