77-414: Ninjemys oweni is an extinct large meiolaniid stem-turtle from Pleistocene Queensland and possibly New South Wales ( Australia ). It overall resembled its relative, Meiolania , save that the largest pair of horns on its head stuck out to the sides, rather than point backwards, the larger scales at the back of its skull and the tail club which is made up of only two tail rings rather than four. With
154-400: A tail club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the ankylosaurids and the glyptodonts , as well as meiolaniid turtles . It is thought that this was a form of defensive armour or weapon that was used to defend against predators , much in the same way as a thagomizer , possessed by stegosaurids , though at least in glyptodonts it
231-465: A carapace length of 1 m (3 ft 3 in) and Niolamia was estimated at 1.2 m (3 ft 11 in). The largest sizes were seemingly reached by Ninjemys and the Wyandotte species. Both were estimated to have reached a similar weight and the latter was estimated to have reached a carapace length of up to 2 m (6 ft 7 in). Notably, these length estimates are restricted to
308-484: A new name for Meiolania oweni and Warkalania , a new genus with reduced horns. Only two new taxa have been named since this boom in the 1990s, with ? Meiolania damelipi representing an uncertain member of this group from Holocene of Vanuatu and Fiji and Gaffneylania being a second genus from the Eocene of Argentina in addition to Niolamia . Meiolania As meiolaniid fossils are often found in
385-516: A secondary, accessory ridge closer to the midline of the skull that is better developed than the one seen in Meiolania , while Niolamia shows no such ridges at all. As in other meiolaniids, the long tail of Ninjemys was encased in a series of bony rings that form a club towards the end. In Ninjemys these rings close towards the bottom like in Niolamia , creating a fully formed circle whereas
462-601: A shell length of approximately 1 m (3 ft 3 in) it is a large turtle and among the largest meiolaniids. Ninjemys is primarily known from a well preserved skull and associated tail armor, which were initially thought to have belonged to the giant monitor lizard Megalania ( Varanus priscus ). The remains of Ninjemys were found at the King's Creek locality in Darling Downs , Queensland, in 1879 by G. F. Bennett, an Australian collector. The King's Creek deposit
539-422: A short communication in which he names Niolamia argentina , a large meiolaniid turtle he claimed was found by his brother Carlos . Simultaneously, Woodward received material from collector Santiago Roth , who had discovered a strikingly similar animal. Roth's find was first figured in a communication by Moreno and was later described in greater detail by Woodward. Having heard of Ameghino's Niolamia argentina ,
616-916: A single species. Doing so regardless would yield the following results, with the groupings being entirely based on the length to width ratio of the horns. In 2015, Sterli recovers M. platyceps and M. mackayi as sister taxa, with M. brevicollis being the basalmost Meiolania species. The Wyandotte species was not used in this analysis due to it being too fragmentary. Niolamia Ninjemys Warkalania Meiolania platyceps Meiolania mackayi Wyandotte species Meiolania brevicollis Niolamia Ninjemys Warkalania Meiolania brevicollis Meiolania mackayi Meiolania platyceps While their internal relationships are relatively well understood, their relation to other turtles has long remained elusive. Throughout their history, they've been variable considered pleurodires , cryptodires or an entirely separate, independent group. Many of
693-503: A sister taxon to the other meiolaniids. Although Gaffneylania likely lived alongside Niolamia , the fragmentary nature of the former makes it somewhat of a wildcard in phylogenetic analysis. It has been recovered as either nesting alongside Niolamia at the base of Meiolaniidae, alongside Ninjemys at the base of the Australasian clade and as a derived genus alongside Warkalania and Meiolania . As far as stable taxa go, Ninjemys
770-471: A system already used in a similar form during early research and later refined by Gaffney. Some consistent features of these scales include the presence of paired G and D scales covering the roof of the skull, a singular X scale sitting at the center of these scales which varies in size between basal and derived genera and unpaired Y and Z scales that sit between the eyes and over the nose. The most prominent scale areas are those designated A to C in order from
847-461: A tail club towards the tip. While their lifestyle was long debated, current research indicates that they were terrestrial herbivores with a keen sense of smell that may have used their heavily armored bodies in intraspecific combat , perhaps during mating season . The research history of meiolaniids is long and at times complicated, with especially the early years suffering from poor records, incorrect identifications and loss of information. Some of
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#1732787725559924-751: A tail ring, dates to the Late Eocene and has been discovered in the Rundle Formation of Queensland. Remains found in Early Miocene Canadian Lead near Gulgong (New South Wales) seem to belong to an intermediate taxon, combining the flattened horns of taxa like Niolamia and Warkalania with the recurved horns of Meiolania . Other continental remains were found in the Late Oligocene Etadunna Formation and Namba Formations (South Australia),
1001-462: A turtle, he proposed it was a member of Pleurodira, the side-necked turtles, which today include Southern Hemisphere groups like chelids , podocnemidids and pelomedusids . Boulenger would find support from Richard Lydekker and meiolaniids were generally viewed as pleurodires for the following decades. Anderson and Simpson both suggested that meiolaniids were part of neither group, instead declaring them descendants of early turtles and placing them in
1078-549: A whole evolve when animals are too large to hide and too small to avoid predation by size alone. In dinosaurs the tail club consists of enlarged and fused Osteoderms , with this (called the knob) in Ankylosaurids being supported by a "handle" of the far distal vertebrae being stiff and using the prezygapophyses to inlock, ensuring rigidity. This dinosaur -related article is a stub . You can help Misplaced Pages by expanding it . This vertebrate anatomy –related article
1155-495: Is believed to be of Pleistocene age, though the precise dating is uncertain. Recognizing the fossil skull as that of a turtle, Bennett sent the material to the Natural History Museum, London , to the prolific paleontologist Richard Owen . However, despite Bennett's letters to Owen correctly identifying the material's origin, Owen assigned the fossil to the giant monitor lizard Megalania , which also included
1232-482: Is believed to have been an herbivore, possibly a grazer like the related Meiolania platyceps . It is generally thought that meiolaniids such as Ninjemys were terrestrial animals that used their spiked bodies and clubbed tails either in intraspecific combat or to fight off predators. Although meiolaniids are well armored even among turtles, theoretically increasing the likelihood that their bones would be preserved, only very few fossils of Ninjemys are known. Although
1309-568: Is clearly differentiated through the horn core anatomy. Indeterminate remains from islands have been discovered in the Pleistocene to Holocene Pindai Caves on New Caledonia , Fiji and Tiga Island . Furthermore, Worthy et al. (2011) reported on what may be the remains of a meiolaniid from the Miocene St Bathans Fauna of New Zealand . However, as the remains do not represent the characteristic horns or tail rings,
1386-470: Is considered to be among the largest species of meiolaniid, with a skull similar in size to that of the Wyandotte species of Meiolania . This is however not reflected by the estimates provided by Rhodin and colleagues, who calculate a potential carapace length of only 1 m (3.3 ft) for Ninjemys but up to 2 m (6.6 ft) for the Wyandotte Meiolania . MacPhee and Sues estimated
1463-400: Is hypothesized it was used in fighting for mating rights . Among dinosaurs, the club was present mainly in ankylosaurids, although sauropods like Shunosaurus also possessed a tail club. Victoria Arbour has established that ankylosaurid tails could generate enough force to break bone during impacts. In a separate study, Arbour suggested tail clubs as well as large armoured herbivores as
1540-560: Is so reduced its even described as being vestigial. The B horns on the other hand are typically well developed and conical rather than flattened. Typically the horns of Meiolania are recurved, resembling the horns of bovines like cows. This is most pronounced in M. brevicollis and the Wyandotte species, which have the proportionally largest horns. However, the large sample size of Meiolania platyceps specimens also highlights how variable these turtles can be, as some individuals show clearly defined B horns while others have them no larger than
1617-896: Is speculated that meiolaniids were also present on the latter, although no fossils of them have yet been found there. Furthermore, meiolaniids may have been present on New Zealand based on the discovery of turtle remains as part of the St Bathans Fauna . Meiolaniids were large animals, with the bigger species reaching total lengths of perhaps up to 2–3 m (6.6–9.8 ft). Meiolaniid remains can easily be identified by their skulls, which are covered in distinctive scale patterns and formed elaborate head crests and horns that vary greatly between genera. While some such as Niolamia had massive frills and sideways facing, flattened horns, others like Meiolania had cow-like, recurved horns. They also had long tails that were covered in spiked rings of bones that, at least in some genera, transitioned into
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#17327877255591694-512: Is the second basalmost genus. It is clearly united with Meiolania due to the second accessory ridge, the broad head and the partially separated internal nares. However, it is excluded from the Warkalania and Meiolania clade due to the size of the A horns and the shape of the D scales. Pictured below is the phylogenetic tree recovered in Sterli, de la Fuente and Krause in 2015. Other than
1771-561: The Latin word "emys" (turtle), a reference to the Teenage Mutant Ninja Turtles . The species name coined by Woodward meanwhile honors Richard Owen, thus Ninjemys oweni . Ninjemys was a large turtle with a broad head and distinct horn-like protrusions along the back of the head and an armored tail ending in a small tailclub . Like in other meilaniids, the skull of Ninjemys was highly ankylosed (fused), obscuring
1848-709: The Middle Jurassic . They are best known from the last surviving genus, Meiolania , which lived in Australia from the Miocene until the Pleistocene , and insular species that lived on Lord Howe Island and New Caledonia during the Pleistocene and possibly the Holocene for the latter. Meiolaniids are part of the broader grouping of Meiolaniformes , which contains more primitive turtles species lacking
1925-494: The crown group . Their analysis recovers meiolaniids as deeply nested in a group of primarily Gondwanan turtles they named Meiolaniformes, which contradictory to the previously held opinion indidcates that meiolaniids sit on a branch of turtles that lies outside of the Pleurodira Cryptodira clade. Pleurodira Cryptodira Chubutemys copelloi Mongolochelys efremovi Tailclub In zoology,
2002-442: The nasal bone of Ninjemys extends much further beyond the rest of the skull, making the skull appear as if it had a pointed nose. Although the external nares only have a single opening, the inner section of the nasal aperture , the inner nostrils, are partially divided in two by bony projections of the nasal and maxillary bone . In addition to the main grinding (triturating) surface of the palate bone , Ninjemys also possessed
2079-606: The wastebasket taxon Amphichelydia. During the 1970s Amphichelydia fell out of use, with groups previously included in it being split among pleurodires and cryptodires. Gaffney at the time argued that meiolaniids were not just cryptodires, but eucryptodires, placing them as a sister group to today's snapping turtles, pond turtles and tortoises , sea turtles as well as pig-nosed and softshell turtles . Fossil discoveries made since them have drastically changed this however. Several genera of Mesozoic turtles have been found to share similarities to meiolaniids, giving crucial insight into
2156-490: The C horns are typically reduced and knob-like. Niolamia possesses the most elaborate A horn, which forms a structure somewhat resembling the frill of a ceratopsian , while the flattened B horns extend to the sides and back. Little is known about the horns of Gaffneylania meanwhile, however the singular known B horn indicates that it may have looked similar to Niolamia , if with more rounded tips. While Ninjemys lived long after these Eocene forms, its horn structure mirrors
2233-440: The C horns. The reason for this is currently unknown, but sexual dimorphism is considered to be unlikely given how these horn morphs are distributed across specimen. The most reduced horns can be observed in Warkalania . Although all three horn types are still present and distinct, they are much more reduced and form neither a large frill nor pronounced B horns, instead only appearing as a relatively subtle ridge extending from behind
2310-731: The Early Miocene Carl Creek Limestone of the Riversleigh (Queensland), the Middle Miocene Wipajiri Formation (South Australia) and the Pliocene Chinchilla Sands (Queensland). Some of these may have beend alongside named genera, indicating that two or more meiolaniids could be found in the same environment. The indeterminate Riversleigh meiolaniid for instance likely coexisted with Warkalania , which
2387-451: The Roth skull to his brother. No new species were named between 1938 and the 1990s. Instead, the vast quantity of fossil material collected on Lord Howe Island led to a series of major publications penned by Eugene S. Gaffney, now renowned for his work on this group. Split across three papers published in 1983, 1985 and 1996, Gaffney described in great detail the skull, vertebrae and finally
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2464-499: The South American genera and likely indicates that this is the basal condition. In Ninjemys too the A horn forms an enlarged frill, even if less pronounced than in Niolamia , and the B horns face straight to the side. Meiolania as the most recent genus represents an extreme in regards to this gradual reduction of the A horn, with the structure only forming a small shelf at the back of the skull. In M. brevicollis this area
2541-530: The additional presence of marsupial bones, pointed out that Meiolania took precedence and thus described the Queensland skull as Meiolania oweni in 1888, thus placing it in the same genus as the Lord Howe Island turtle. Due to its proximity to the skull material, the armored tail ring and club were both considered to have also been those of Meiolania oweni . There is however the possibility that
2618-457: The affinities of this form may change. The most defining feature of meiolaniids is the presence of clearly defined scale areas covering the skull . In meiolaniids, the individual plates that form the skull are highly ankylosed, meaning they are fused with each other to a degree that typically makes it impossible to determine where one element ends and the other begins. Despite the absence of such sutures however, researchers can readily distinguish
2695-523: The already great width of Ninjemys' skull, with the distance between them being close to 70 cm (28 in). This however renders it impossible for the turtle to retract the head into its shell. The A scale area, which is located behind the B horns and forms the back edge of the skull, is intermediate in size between those of the Argentinian Niolamia (large A scale) and Meiolania (small A scale). The C horns, which are located before
2772-488: The back of the carapace had a serrated edge. Osteoderms that covered the limbs have been recovered from both Meiolania and Gaffneylania and the overall morphology of the legs, which is robust with blunt toes, also supports terrestrial locomotion. Meiolaniids were large and robust animals. Even the smaller species, namely Meiolania mackayi , have been estimated to have reached a carapace length of 0.7 m (2 ft 4 in). Meiolania platyceps could have reached
2849-556: The back of the skull and designated A, B and C (from back to front) by Gaffney. A unique feature of Ninjemys is the orientation of the second pair of horns, known as B horns. In Meiolania these horns are curved backwards, somewhat resembling cows and not forming a continuous shelf with the other horns. However, in Ninjemys these prominent horns are straight and directed towards the side. They are also not as conical as in Meiolania and instead are somewhat flattened. These horns add to
2926-465: The back-most area to the front-most pair. These scale areas, commonly referred to as horns or horn cores due to their size and shape, are very pronounced and highly distinct in the individual genera and even species. Generally speaking, the A horn is a singular element located at the back of the skull that ranges from forming a large, frill-like structure to an almost vestigial shelf. The B scales are paired and appear more horn-like in their morphology, while
3003-399: The bony shell and do not factor in the combined length of the head, neck and long tail. This may indicate that meiolaniids could have reached lengths of up to 3 m (9.8 ft). Phylogenetic analysis consistently recovers Meiolaniidae as a monophyletic group with well resolved internal relationships. Among the most important features in this are the different scale areas, which provide
3080-542: The chimeric hypodigm of Megalania into monitor lizard, marsupial and turtle remains, with the name being constrained to the lizard. While this marked the end of Meiolania as a lizard, Woodward agreed with Owen in that the skull from the mainland clearly belonged to an animal related to Meiolania . Woodward placed it in the same genus, naming it Meiolania oweni in Owen's honour. Shortly afterwards, M. platyceps and M. minor were synonymized with one another. What followed
3157-463: The chimeric material from the mainland, he subsequently named the Lord Howe material Meiolania (small roamer). This has however led to some confusion, as the etymology of Meiolania was never specified in the actual publication. Eugene S. Gaffney would later suggest that "-lania" actually translated to " butcher ", a notion later contested in the works of Juliana Sterli . Owen's identification
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3234-418: The club appears to be made from two segments that are fused with each other and form a spiked sheath, while in Meiolania this club is larger, formed by four distinct elements. The spikes seen on the prior tail rings continue onto the tail club, where they typically decrease in size towards the end. Other parts of the skeleton are harder to compare due to the incomplete nature of most meiolaniids, with much of
3311-415: The different genera and species through the presence of marks left by the overlying scale areas, with are either present through faint grooves or raised ridges. These scale areas, at times also simply referred to as scales or scutes, are largely homologous with one another and can easily be compared. To simplify diagnosis and create a consistent naming scheme, these scale areas are labeled with capital letters,
3388-582: The distinctive morphology of meiolaniids, known from the Early Cretaceous-Paleocene of South America and Australia. Meiolaniidae includes a total of five different genera, with Niolamia and Gaffneylania native to Eocene Patagonia and the remaining taxa, Ninjemys , Warkalania and Meiolania being endemic to Australasia . The group is believed to have evolved on the continent of Gondwana prior to its split into South America, Australia and Antarctica . For this reason it
3465-478: The earliest supposed discoveries made by western scientists are said to date to the middle of the 19th century, with writings suggesting that various locals and visitors of Lord Howe Island , situated off the eastern coast of Australia, discovered the remains of large turtles. The first well supported finds came just prior to the 1880s, when a large skull of what is now known as Ninjemys was discovered in Queensland and sent to paleontologist Richard Owen . Although
3542-428: The enlarged B horns, are rather small and conical. The top of the head, predominantly formed by scale area D, is raised to form a shallow dome rather than the flat head of Meiolania . The D scales likely met in the middle of the skull, adjacent to a singular scale X situated right in the middle. The scale areas Y and Z, which cover the top of the snout in Ninjemys are both relatively large. Unlike in other meiolaniids,
3619-479: The eyes to the back of the head. Aside from the large horns present on the skulls, meiolaniids are also characterized by their heavily armored tails. It is believed that the entirety of the tail in meiolaniids was covered in bony rings flanked by at least two pairs of spikes. Such bone rings are known from even the most basal genus, Niolamia , and surrounds the entire circumference of the tail in it and Ninjemys . The individual rings appear to correlate directly with
3696-571: The form of broken horn cores and tail rings, much of the collected material is only present in the form of fragmentary remains too scrappy to be named or even assigned to any existing species. Due to this, much of meiolaniid diversity is only known to science in the form of various fossils designated Meiolaniidae indeterminate. However, even if fragmentary, this material nonetheless shows that members of this group were diverse and widespread throughout Cenozoic Australia. The oldest unnamed meiolaniid from Australia, known based on shell remains, osteoderms and
3773-534: The fossils was correctly identified by its collector, G. F. Bennett, Owen instead believed the skull to have belonged to a type of lizard. Combining the skull with the vertebrae of the giant monitor lizard Megalania and the foot bones of a marsupial , Owen came to believe that the bones represented a type of giant thorny devil . By 1884 better recorded fossil discoveries had been made on Lord Howe Island, with multiple shipments being sent to Owen in London. Again,
3850-535: The genus Ninjemys for this species. There are several isolated meiolaniid remains which may be examples of Ninjemys , however it is not certain if they actually stem from the same taxon. In at least one case, the fragments of a tail club found in New South Wales , Gaffney assigns the material to cf. Ninjemys oweni . Gaffney explains the etymology of Ninjemys to be "in allusion to that totally rad, fearsome foursome epitomizing shelled success" combined with
3927-519: The genus paraphyletic or require the diagnostic characters of Meiolania to be altered, with Gaffney creating the genus Ninjemys to retain the prior diagnosis of the genus. Furthermore, detailed study of Ninjemys showed that in certain regards it was more similar to the much older Niolamia from the Eocene of Argentina. While Gaffney considers Niolamia a basal member of Meiolaniidae, Ninjemys and Meiolania are united by some derived features such as
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#17327877255594004-442: The information stemming from Meiolania platyceps itself. The shell of Meiolania is domed rather than flattened, one of several traits indicative of a terrestrial lifestyle. However, the carapace is not quite as high as seen in today's aldabra giant tortoises and galapagos giant tortoises , instead bearing more resemblance to that of the gopher tortoise . Shell elements of Niolamia , Gaffneylania and Meiolania all show that
4081-475: The key sources of confusion regarding Niolamia . While these early publications largely treated Ameghino's and Roth's turtles as separate specimens, the former never provided a detailed diagnosis, description or even figure of his material. At the same time however, Ameghino claimed knowledge over where Roth's material originated. Recent research conducted on the history of Niolamia suggests that there never were two specimens, and that Ameghino simply missattributed
4158-900: The later causing it to appear in several possible positions within Meiolaniidae. The two phylogenetic trees below show Ninjemys' position in Meiolaniidae as recovered by Gaffney, Archer & White (1992) and Sterli, de la Fuente & Krause (2015). Niolamia argentina Ninjemys oweni Warkalania carinaminor Meiolania brevicollis Meiolania platyceps Meiolania sp. Meiolania mackayi Crown Testudines Chubutemys copelloi Mongolochelys efremovi Peligrochelys walshae Otwayemys cunicularius Kallokibotion bajazidi Niolamia argentina Gaffneylania auricularis ? Ninjemys oweni Gaffneylania auricularis ? Warkalania carinaminor Gaffneylania auricularis ? Meiolania platyceps Like other meiolaniids, N. oweni
4235-405: The majority of characters used in phylogenetic analysis of this group. Niolamia is consistently found to be the basalmost meiolaniid, sitting at the base of the tree as a sister to all Australasian forms. This matches its geographic range and age, which clearly separates it from younger meiolaniids. Some of the seemingly ancestral scale conditions of Niolamia includes the enormous A scale area and
4312-680: The material could have belonged to a second type of meiolaniid, known to have been present in Pleistocene Queensland. By 1992 meiolaniid turtles had become understood enough for researchers to recognize clear anatomical differences between Meiolania platyceps and Meiolania oweni , which they had already begun to refer to as "Meiolania" oweni . As the material lacked the synapomorphies of Meiolania proper, Eugene S. Gaffney and other researchers argued that it should be placed within its own genus as it would otherwise render Meiolania paraphyletic . To amend this issue, Gaffney coined
4389-408: The material had been correctly identified as having belonged to turtles by local collectors and researchers, but was then misattributed to lizards by Owen. It was based on this material that Owen named the genus Meiolania in 1886 to include two species, M. platyceps and M. minor , believing it to be a small relative of the mainland specimen. As Owen had given the name Megalania (great roamer) to
4466-433: The missidentified leg bones of diprotodontid marsupials . 1880 saw the discovery of a fossil of a fully armored tail, later described as resembling that of a Glyptodon , which was recovered from the same spot in King's Creek that also yielded the turtle skull. Like the skull, this partial tail was initially assigned to Megalania . The chimeric nature of Owen's giant lizard was still not recognized by him when he described
4543-412: The more laterally directed B horns, both traits shared with the basalmost Australian form Ninjemys . The basal condition of Niolamia is further supported by comparing the basicranium to other turtle groups, as the intrapterygoid appears more "primitive" compared to that of Meiolania and compares favorably with sinemydids . The absence of an accessory grinding surface in the jaws also identifies it as
4620-431: The potential origin of the group. The first instance of this was recognized as early 1987, when Ckhikvadzé grouped Mongolochelys , Kallokibotion and meiolaniids in a single group. In 2000 Hirayama et al. expanded on this idea, grouping Mongolochelys , sinochelyds , Otwayemys and meiolaniids together, as did subsequent authors. Chubutemys and Patagoniaemys followed in 2007 and 2011, while Peligrochelys
4697-661: The precise reason for the lack of known fossils is not known, it has been suggested that this could have been the consequence of Ninjemys being a generally rather rare animal in its native habitat, which currently only consists of Queensland and possibly New South Wales. Meiolaniid Meiolaniidae is an extinct family of large, probably herbivorous stem-group turtles with heavily armored heads and clubbed tails known from South America and Australasia . Though once believed to be cryptodires , they are not closely related to any living species of turtle, and lie outside crown group Testudines , having diverged from them around
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#17327877255594774-403: The presence of a second accessory ridge, the broad head and the partially separated internal nares. The large size of the A horns as well as the form of the D scale areas do however exclude it from the clade formed by the two most derived meiolaniids, Meiolania and Warkalania . The relationship with Gaffneylania on the other hand remains uncertain, primarily due to the fragmentary nature of
4851-480: The problems responsible for this varying placement can be found in the incompleteness of meiolaniid remains and their highly derived nature. After meiolaniids were recognized as turtles, Huxley suggested they were related to modern snapping turtles (genus Chelydra ), placing it in Cryptodira, the group that includes most living turtles and tortoises. While Boulenger agreed with the identification of Meiolania as
4928-573: The remains of a third meiolaniid were discovered in 1898 across the Pacific in Argentina . The precise history of these events is however poorly understood due to a large amount of conflicting information. At the time, two rivaling groups of paleontologists, one led by Florentino Ameghino and the other by Francisco Moreno , were competing in a fashion similar to the Bone Wars . Ameghino published
5005-420: The remains of another meiolaniid turtle in 1886, Meiolania from Lord Howe Island , continuing to believe that the two were lizards related to the thorny devil . It was Thomas Henry Huxley who first identified Meiolania as a turtle in 1887 and placed the Queensland skull alongside it in the genus Ceratochelys . A. S. Woodward , who was examining the various materials assigned to Megalania and recognized
5082-409: The researcher concluded that Roth's turtle represented the same species, but placed both in the genus Miolania (likely a misspelling of Meiolania ). Later finds in the area would produce the taxon Crossochelys corniger , now thought to be a juvenile Niolamia and around the same time the Roth skull was elevated to the genus' neotype as Ameghino's skull could not be found. This highlights one of
5159-441: The results of doing so are highly questionable. Only two species would be complete enough to provide valuable characters, as M. mackayi is likely a synonym of M. platyceps and the wyandotte species is only represented through horn cores. This renders the morphology of the B horns the only way to possibly determine relationships within the established Meiolania species, a trait that has been proven to be highly variable even within
5236-444: The rings in Meiolania are open at the bottom. The bony rings form several spikes that protrude outwards, with Ninjemys possessing two pairs. The smaller lateral bosses, which vary in their position based on where on the tail the ring is situated, and a pair of larger spikes atop the ring. The tail club was comparably short, created from only two spiked segments rather than four like in Meiolania , but overall more massive. Ninjemys
5313-407: The shell and limbs of Meiolania platyceps , providing the most extensive look at this taxon to date. This detailed look at the type species ran in tandem with several studies examining meiolaniid fossils from other localities. 1992 saw the description of three new meiolaniid taxa in the span of a single year, consisting of the new species Meiolania brevicollis from mainland Australia, Ninjemys as
5390-446: The sutures between the individual cranial bones. However, the scales covering the head and the horns of meilaniids leave prominent marks on the underlying bone, which have been used as substitutes for the fused sutures and are deemed diagnostic for the different genera. Additionally, the shape and size of the horns of these turtles also differs notably between the members of this family. The most prominent horns or scale areas are located at
5467-443: The vertebrae, meaning that each vertebra is surrounded by a singular ring that articulates with those before and after it. The sides of the ring form bony spikes, one smaller pair that faces towards the side and one larger pair that juts out more dorsally. Some forms, namely Ninjemys and Meiolania , also preserve a tail club that tips the end of the tail and has been compared to those of glyptodonts and ankylosaurs . In Ninjemys
5544-447: The weight of Ninjemys at 200 kg (440 lb) and give a similar estimate for the Wyandotte Meiolania (listed as Meiolania sp. ), further supporting previous claims of Ninjemys being one of the largest members of its family. Although Ninjemys was initially placed in the genus Meiolania , Gaffney argued in 1992 that it is morphologically distinct from the genus. Continuing to place Ninjemys in Meiolania would either render
5621-414: The wildcard Gaffneylania , the phylogenetic tree matches with prior work by Gaffney. Niolamia argentina Gaffneylania auricularis Ninjemys oweni Gaffneylania auricularis Warkalania carinaminor Gaffneylania auricularis Meiolania platyceps Creating a phylogenetic tree for the individual species of Meiolania is theoretically possible, however as discussed by Gaffney,
5698-541: Was a connection to lizards, with Meiolania possibly representing a relative to both reptile groups. For this new clade, Owen coined the name Ceratosauria, unaware the name was already occupied by a group of dinosaurs as defined by Othniel Charles Marsh in 1884. In spite of Owen's conviction, more and more researchers published on the turtle identity of Meiolania . George Albert Boulenger placed Meiolania in Pleurodira and Arthur Smith Woodward officially split
5775-439: Was a long, uninterrupted period of fossil collection on Lord Howe Island, providing a massive quantity of fossil material. Although excavations were productive, this time period was relatively uneventful in regards to taxonomy, with the only Australasian Meiolania species named in this period being M. mackayi from Walpole Island south of New Caledonia in 1925. Parallel to the later stages of this initial burst of revisions,
5852-430: Was described in 2012. Both Mongolochelys and Peligrochelys show scale areas similar to those characteristic for meiolaniids and several other anatomical features have been observed uniting these Mesozoic turtles with meiolaniids. Sterli and de la Fuente conclude that the presence of well defined scale areas present on the skull may have been plesiomorphic for all turtles, and was simply lost and re-evolved repeatedly in
5929-603: Was soon criticized by other scientists in London, who agreed with the Australian researchers in that these remains were actually those of turtles, not lizards. Just one year after Meiolania was named, Thomas Henry Huxley published a paper correcting Owen and naming the material Ceratochelys sthenurus , to which Huxley further assigned the Queensland skull. Owen meanwhile, who had received more material from Australia, slightly amended his prior research. While now also recognizing some turtle affinities, Owen maintained that there
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