| 1. |
- Blom, Henning, 1969-
(författare)
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A new anaspid fish from the middle Silurian Cowie Harbour fish bed of Stonehaven, Scotland
- 2008
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Ingår i: Journal of Vertebrate Paleontology. - 0272-4634 .- 1937-2809. ; 28:3, s. 594-600
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Tidskriftsartikel (refereegranskat)abstract
- A new birkeniid anaspid, Cowielepis ritchiei gen. et sp. nov., from the mid Silurian Cowie Harbour fish bed in Scotland is described on the basis of three specimens. Although sharing characters with various well-known anaspids, it possesses a unique combination of features that justifies the establishment of a new genus. Cowielepis is characterized by a single row of dorsolateral scales and a distinctive skull roof pattern with a large pineal plate and elongated posterior plates. The presence of paired ventrolateral fins in C. ritchiei supports previous suggestions that all anaspids possess such fins, but leaves open the question of homology with the gnathostome pectoral fin.
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| 2. |
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| 3. |
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| 4. |
- Snitting, Daniel
(författare)
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A Redescription of the Anatomy of the Late Devonian Spodichthys Buetleri Jarvik, 1985 (Sarcopterygii, Tetrapodomorpha) from East Greenland
- 2008
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Ingår i: Journal of Vertebrate Paleontology. - 0272-4634 .- 1937-2809. ; 28:3, s. 637-655
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Tidskriftsartikel (refereegranskat)abstract
- The tetrapodomorph fish Spodichthys buetleri from the Upper Devonian of East Greenland is redescribed from computed tomography scans of material originally studied by Erik Jarvik. A wealth of new anatomical data was revealed by scanning the nearly perfectly three-dimensional specimens, including detailed information on the shape of the brain cavity and the internal structure of the lower jaws. Spodichthys displays an interesting mix of generalized “osteolepidid,” or primitive tetrapodomorph, and tristichopterid features. Derived characters shared by Spodichthys, tristichopterids and (Panderichthys + Tetrapoda) include the loss of cosmine, a small kite-shaped parasymphysial plate, and a long commissural lamina of the entopterygoid. The presence of an extratemporal lateral to the tabular and a single fang position on the posterior coronoid and ectopterygoid are examples of basal tetrapodomorph characters retained in Spodichthys. Spodichthys is unique in having coronoid fangs positioned lateral to the corresponding replacement pit rather than having an anterior-posterior alternation between developed fang and replacement pit, which is the normal tetrapodomorph condition. Jarvik's original conclusion that Spodichthys is closely related to the tristichopterids is confirmed by a phylogenetic analysis, which places Spodichthys as the sister taxon of the Tristichopteridae.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
- Borinder, Niclas H., et al.
(författare)
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Postcranial osteology of the basally branching hadrosauroid dinosaur Tanius sinensis from the Upper Cretaceous Wangshi Group of Shandong, China
- 2021
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Ingår i: Journal of Vertebrate Paleontology. - : Taylor & Francis. - 0272-4634 .- 1937-2809. ; 41:1
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Tidskriftsartikel (refereegranskat)abstract
- Tanius sinensis was one of the first dinosaur species to be named from China. It was established on a partial skeleton recovered by a joint Sino-Swedish expedition in 1923. The fossils were excavated from Upper Cretaceous strata of the Jiangjunding Formation (Wangshi Group) in Shandong Province, and although their discovery dates back almost 100 years, they have not been reassessed in detail since their initial description in 1929. This omission is critical because T. sinensis is now recognized as one of the stratigraphically youngest non-hadrosaurid hadrosauroid taxa. Here, we re-evaluate the postcranial osteology of T. sinensis as a prelude to an anatomical and phylogenetic revision of the species. We examined the holotype and all currently referred specimens of T. sinensis first-hand, and identified a unique postcranial character state combination incorporating tall dorsal neural spines, a reduced postacetabular ridge on the ilium, a fully enclosed flexor tunnel formed by the distal condyles of the femur, and a lunate proximal end on metatarsal III. Comparisons with other species of Tanius confirm that: (1) T. chingkankouensis is a nomen dubium erected on non-diagnostic composite material; (2) T. laiyangensis was established on indeterminate hadrosaurid remains that are not attributable to Tanius; and (3) the anecdotal assignments of Bactrosaurus prynadai and Tsintaosaurus spinorhinus to Tanius cannot be substantiated. Close inspection of the holotype caudal vertebra further reveals a possible healed bite trace consistent with a prey-predator interaction. Lastly, our calculated average body mass estimate for T. sinensis of between 2091-3533 kg suggests that it was one of the largest non-hadrosaurid hadrosauroids.
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| 12. |
- Bremer, Oskar, 1985-, et al.
(författare)
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Exploring the three-dimensional vasculature of dermal hard tissues in thyestiid osteostracans using synchrotron radiation microtomography
- 2023
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Ingår i: Journal of Vertebrate Paleontology. - : Taylor & Francis. - 0272-4634 .- 1937-2809. ; 42:4
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Tidskriftsartikel (refereegranskat)abstract
- Osteostracans are stem-gnathostomes with bony tissues that represent an important link between living jawed and jawless vertebrates, the latter of which lack skeletal hard tissues. In this study, a number of skeletal microremains from a diverse group of osteostracans called thyestiids have been investigated using propagation phase-contrast X-ray synchrotron microtomography. This enabled detailed reconstructions of their three-dimensional vasculature. The dermal skeleton of thyestiids is divided into three layers that vary in proportion between taxa, similar to gnathostomes and other osteostracans. The basal layer is confirmed as an acellular bony tissue composed of fiber bundles that contains narrow, vertical canals and/or large cavities. Bundles bend around smaller canals but form jagged edges around larger cavities, which suggests delayed mineralization. The presumed vascular mesh canals of the deep middle layer are radially arranged in some taxa, but more irregular or even tree-like in others, suggesting a relation to how the elements developed and grew. A number of mesh canals ascend toward the superficial layer where they supply the subepidermal vascular plexus, or create pore fields that open to the surface in some taxa. These ascending mesh canals most likely expanded and formed a network of canals underneath more extensive pore fields. Aestiaspis viitaensis has a simple upper canal system above these fields, while Tremataspis mammillata and Tr. milleri scales have a polygonal network of upper mesh canals above extensive perforated septa. These systems are most likely homologous, but their relation to intra- and inter-areal canals described in other osteostracans remains ambiguous.
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| 13. |
- Campione, Nicolas E., 1982-, et al.
(författare)
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Varanops brevirostris (Eupelycosauria: Varanopidae) from the Lower Permian of Texas, with discussion of varanopid morphology and interrelationships
- 2010
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 30:3, s. 724-746
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Tidskriftsartikel (refereegranskat)abstract
- A comprehensive revision of Varanops brevirostris on the basis of a large, well-preserved specimen from a new Lower Permian locality in Texas provides valuable new anatomical information and additional autapomorphies for this varanopid synapsid taxon. These include the loss of the postorbital boss, the presence of a smooth transition between the dorsal and lateral surfaces of the postorbital, hypertrophied basipterygoid processes, the presence of deep, elongate lateral neural spine excavations, posterior dorsal vertebrae with dorsally tapered neural spines, and a deep groove proximal to the femoral fourth trochanter. Furthermore, this specimen is the first fully developed adult specimen of Varanops, and it preserves the most complete lower jaw of the taxon. A revised phylogenetic analysis places V. brevirostris as the sister taxon to the Varanodon-Watongia clade. A stratocladistic analysis assessing varanopid relationships by incorporating a stratigraphic character into the analysis recovers the same topology among varanodontines, but an alternate topology between mycterosaurines and Elliotsmithia longiceps.
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| 14. |
- De La Garza, Randolph Glenn, et al.
(författare)
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A fossil sea turtle (Reptilia, Pan-Cheloniidae) with preserved soft tissues from the Eocene Fur Formation of Denmark
- 2021
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 41:3
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Tidskriftsartikel (refereegranskat)abstract
- A new hard-shelled sea turtle (Pan-Cheloniidae) with vestigial soft tissues from the lower Eocene (Ypresian) Fur Formation of Denmark is described and illustrated. The fossil (DK 807) comprises a partial, yet fully articulated carapace (estimated original length ∼50 cm) where the individual bones mostly are preserved in three dimensions, together with an intact sacrum, a consecutive series of articulated caudal vertebrae, a complete pelvic girdle, and both hind limbs. Primitive characters in the pelvis and limbs, along with free ribs that contact the posterior peripherals suggest affinity with the extinct pan-cheloniid Eochelone; however, because of the incomplete nature of the fossil, DK 807 is kept in open nomenclature. Associated with the skeletal elements are soft-tissue residues that include remnant epidermal scutes and a nearly complete outline of a rear paddle. The flipper-shaped halo likely represents traces of skin preserved as a dark bedding-parallel film. Its wrinkled and striated surface texture attests to an originally scaleless configuration comparable to the soft integument of living adult dermochelyid (leatherback) turtles, and unlike that of extant cheloniids. Scratches, scars and indentations on the bony carapace likely represent incompletely healed bite marks inflicted by a crocodylian or another large-sized seagoing tetrapod.
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| 15. |
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| 16. |
- Dupret, Vincent, et al.
(författare)
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Redescription of Szelepis Liu, 1981 (Placodermi, Arthrodira), from the Lower Devonian of China
- 2017
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 37:2
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Tidskriftsartikel (refereegranskat)abstract
- The skull roof of the species Szelepis yunnanensis (Liu, 1979) from the Early Devonian of Yunnan is redescribed, as well as other Szelepis material previously published. It appears that only the holotype of S. yunnanensis can be confidently assigned to this genus. The fusion of the preorbital plates into one plate strongly suggests the assignment of Szelepis yunnanensis to the monophyletic family Actinolepididae Gross, 1940, sensu stricto (comprising Actinolepis Agassiz, 1884, and Bollandaspis Schmidt, 1979). This is confirmed by a phylogenetic analysis. Hence, Szelepis constitutes the most ancient occurrence of the family but not the sister group to the remaining members.
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| 17. |
- Dupret, Vincent, 1977-, et al.
(författare)
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The skull of Hagiangella goujeti Janvier, 2005, a high-crested acanthothoracid (Vertebrata, Placodermi) from the Lower Devonian of northern Vietnam
- 2011
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 31:3, s. 531-538
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Tidskriftsartikel (refereegranskat)abstract
- The acanthothoracid Hagiangella goujeti Janvier, 2005, has been described exclusively on the basis of isolatedthoracic plates from the Lochkovian (Lower Devonian) Khao Loc Formation of Tung Vai, Ha Giang Province, northernVietnam. It is characterized by a very high, triangular median crest on the median dorsal plate, and has been referred to theAcanthothoraci on the basis of the morphology of its fused anterolateral, spinal and anterior ventrolateral plates, and thecharacteristic stellate ornamentation of the group. Isolated plates of H. goujeti are relatively abundant at Tung Vai and noother placoderm taxon from this locality seems to share the same type of ornamentation. However, the skull of this speciesremained elusive. Here we report two well-preserved skull roofs from Tung Vai, which we refer to H. goujeti. They display thesame stellate ornamentation and small size as the previously described plates of the thoracic armor of this species. This newmaterial shows that the head of H. goujeti is surprisingly short (i.e., possibly lacking dermal rostral and pineal elements), incontrast to the elongate and narrow skull of all other acanthothoracids. The combination of unique characters (e.g., presenceof two pairs of posterior pit lines, two pairs of central and paranuchal plates, etc.) suggests a possible sister group relationshipto the placoderm assemblage Petalichthyida + Ptyctodontida + Arthrodira.
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| 18. |
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| 19. |
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| 20. |
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| 21. |
- Friedman, Matt, et al.
(författare)
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A reappraisal of the origin and basal radiation of the Osteichthyes
- 2010
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 30:1, s. 36-56
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Tidskriftsartikel (refereegranskat)abstract
- The earliest Actinoptergyii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes) have been studied intensely, and a consistent picture of interrelationships has begun to emerge for the latter. In contrast, there has been minimal documentation of the pattern of character acquisition leading to the osteichthyan crown. We review the synapomorphies proposed for various levels within osteichthyan phylogeny (total group; Acanthodes + crown group; crown group; Sarcoptergyii; Actinopterygii), confirming some, rejecting others, and making new additions. This distribution of characters is used to interpret the placement of problematic Siluro-Devonian genera traditionally assigned to Actinopterygii, and suggests these taxa are stem osteichthyans. Earlier placements of these forms within the crown are symptomatic of taxonomies based on unpolarized similarities rather than synapomorphies.
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| 22. |
- Hairapetian, Vachik, et al.
(författare)
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Early Frasnian thelodont scales from central Iran and their implications for turiniid taxonomy, systematics and distribution
- 2016
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 36:3
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Tidskriftsartikel (refereegranskat)abstract
- We describe isolated shark teeth collected in levels of the Calafate Formation (Maastrichtian, Late Cretaceous) on the southeast coast of Argentino Lake, Calafate City, Santa Cruz Province, Argentina. The teeth belong to the hexanchiform Notidanodon dentatus, a new species of the squaliform Protosqualus, and an indeterminate species of the echinorhiniform genus Echinorhinus. The record of Notidanodon constitutes the first in South America. The report of Notidanodon associated with plesiosaur remains is in accordance with previous records from around the world. Protosqualus argentinensis, nov. sp., which is the first record of the genus in South America, is characterized by having teeth with a apicobasally tall root and serrated cutting edges, among other features.Echinorhinus sp. constitutes one of the oldest records of this genus on the continent and one of the few Mesozoic records worldwide. This shark association is clearly distinct from coeval selachian faunas from northern Patagonia, which exhibit clear Tethyan influences. Instead, it shows some similarities to other high-latitude selachian faunas, including Australia, New Zealand, and Antarctica. It is possible that the Cretaceous selachian assemblages of Patagonia may be separated into two different associations: northern Patagonian faunas are related to more temperate associations of lower paleolatitudes, whereas those of southern Patagonia are closer to other southern localities.
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| 23. |
- Holland, Timothy, et al.
(författare)
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New information on the enigmatic tetrapodomorph fish Marsdenichthys longioccipitus (Long, 1985)
- 2010
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 30:1, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- The tetrapodomorph fish Marsdenichthys longioccipitus from the Givetian-Frasnian of Mt. Howitt, Victoria, Australia, occupies an uncertain phylogenetic position. Marsdenichthys has been linked to the base of the Tristichopteridae, as well as to the poorly known Northern Hemisphere form Rhizodopsis, based on the presence of rounded scales bearing a median boss on the internal surface. However, its affinities to these taxa are ambiguous, due to the incomplete preservation of the two Marsdenichthys specimens initially described. For the first time, we present significant information regarding the cheek and palate of Marsdenichthys, based on the descriptions of two new specimens from Mt. Howitt. New autapomorphies for Marsdenichthys are proposed, including the presence of a bar-like maxilla being approximately equal in depth to the dentary, and a rectangular anterior termination of the lacrimal. Several plesiomorphic features are described from the palate, including rounded vomer morphology lacking a posterior process, a relatively short, broad parasphenoid, and a dermopalatine approximately equal in length to the ectopterygoid. No synapomorphies are shared between Marsdenichthys and tristichopterids. Scale morphology is redescribed, and shown to exhibit concentric rings on the external surface, as in Rhizodopsis. However, differences in skull morphology, such as the lack of an external opening for the pineal foramen in Rhizodopsis, suggest that this scale morphology may have evolved independently.
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| 24. |
- Konishi, Takuya, et al.
(författare)
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Platecarpus tympaniticus (Squamata, Mosasauridae): osteology of an exceptionally preserved specimen and its insights into the acquisition of a streamlined body shape in mosasaurs
- 2012
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 32:6, s. 1313-1327
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Tidskriftsartikel (refereegranskat)abstract
- LACM 128319, which was collected in western Kansas, U. S. A., and is assignable to Platecarpus tympaniticus (Mosasauridae, Plioplatecarpinae), represents arguably one of the most exquisite mosasaur specimens known to date. Measuring 5.67 m from the tip of the snout to the end of the tail, it comprises an exceptionally well-articulated skeleton, accompanied by soft-tissue remains, such as skin impressions and tracheal cartilage. P. tympaniticus is one of the most numerously collected mosasaur taxa in North America, but as most specimens are fragmentary or reconstructed to various degrees, LACM 128319 provides a unique opportunity to document the taxon's osteology from a single skeleton. In this study, we first present a detailed osteological description of LACM 128319. Following this, we present an analysis of the evolution of a streamlined body shape in P. tympaniticus, specifically by comparing the length distribution of the dorsal ribs in relevant anguimorphan taxa. We conclude that both an anterior migration of the rib cage and an increasing regionalization within the dorsal vertebral series are key features contributing to formation of a streamlined body profile in P. tympaniticus, and probably in many other hydropedal members of mosasaurs.
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| 25. |
- Kriwet, Jürgen, et al.
(författare)
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Ultimate Eocene (Priabonian) chondrichthyans (Holocephali, Elasmobranchii) of Antarctica
- 2016
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809.
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT—The Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula, is known for its remarkable wealth of fossil remains of chondrichthyans and teleosts. Chondrichthyans seemingly were dominant elements in the Antarctic Paleogene fish fauna, but decreased in abundance from middle to late Eocene, during which time remains of bony fishes increase. This decline of chondrichthyans at the end of the Eocene generally is related to sudden cooling of seawater, reduction in shelf area, and increasing shelf depth due to the onset of the Antarctic thermal isolation. The last chondrichthyan records known so far include a chimeroid tooth plate from TELM 6 (Lutetian) and a single pristiophorid rostral spine from TELM 7 (Priabonian). Here, we present new chondrichthyan records of Squalus, Squatina, Pristiophorus, Striatolamia, Palaeohypotodus, Carcharocles, and Ischyodus from the upper parts of TELM 7 (Priabonian), including the first record of Carcharocles sokolovi from Antarctica. This assemblage suggests that chondrichthyans persisted much longer in Antarctic waters despite rather cool sea surface temperatures of approximately 5C. The final disappearance of chondrichthyans at the Eocene–Oligocene boundary concurs with abrupt ice sheet formation in Antarctica. Diversity patterns of chondrichthyans throughout the La Meseta Formation appear to be related to climatic conditions rather than plate tectonics.
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| 26. |
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| 27. |
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| 28. |
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| 29. |
- LeBlanc, Aaron R. H., et al.
(författare)
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Aquatic adaptation, cranial kinesis, and the skull of the mosasaurine mosasaur Plotosaurus bennisoni
- 2013
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 33:2, s. 349-362
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Tidskriftsartikel (refereegranskat)abstract
- New anatomical observations of the holotype skull of Plotosaurus bennisoni from the Maastrichtian Moreno Formation of California, U.S.A., are used as a framework to examine cranial kinesis in derived members of the Mosasaurinae. Enlarged posteromedial flanges of the frontal and extensive lateral contacts of the prefrontal and postorbitofrontal contributed to increased rigidity along the frontoparietal suture (the mesokinetic joint). Sutural contacts of the parietal with the supraoccipital posteriorly and the prootic ventrally would have restricted metakinetic movements. Furthermore, the unusual shape of the epipterygoid, and its dorsal contact with the prootic and parietal, shows that the epipterygoid and pterygoid were probably not capable of anteroposterior movements. Most strikingly, Plotosaurus exhibits a tight association of the quadrate with the temporal arcade, suggesting that streptostyly was limited or lost in this derived mosasaurine, the loss of such a feature having never been described in a mosasaur. These charcteristics are placed in a functional context to examine aquatic adaptations in mosasaurs. As one of the most specialized mosasaurs known, the loss of cranial kinesis may have evolved as a result of its piscivorous diet.
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| 30. |
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| 31. |
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| 32. |
- Maxwell, Erin E., et al.
(författare)
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Postcranial anatomy of Platypterygius americanus (Reptilia: Ichthyosauria) from the Cretaceous of Wyoming
- 2010
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 30:4, s. 1059-1068
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Tidskriftsartikel (refereegranskat)abstract
- Ichthyosaurs remains from the Albian and Cenomanian of Wyoming have been assigned to Platypterygius americanus, but apart from structures of the distal humerus, few other unequivocal character states have been proposed to differentiate this species from its congeners. The purpose of this study was to reevaluate the postcranial morphology of Platypterygius americanus, in order to assess the validity of this species and distinguish postcranial traits relevant for specific diagnoses. Several applicable features were identified, including the location of extrazeugopodial facets on the distal humerus and femur, shape of the intermedium, relative degree of fusion within the atlas-axis complex, number of presacral centra, and varying lengths of the anterior caudal centra. Comparative assessment suggests that Platypterygius americanus is a valid taxon, and that it is possible to differentiate the various Platypterygius spp. independent of stratigraphical and/or geographical occurrence data. Nevertheless, a future review of cranial morphology in all Platypterygius spp. is necessary to bolster these conclusions.
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| 33. |
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| 34. |
- Mörs, Thomas, 1962-, et al.
(författare)
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A new large beaver (Mammalia, Castoridae) from the Early Miocene of Japan
- 2016
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Ingår i: Journal of Vertebrate Paleontology. - : Society of Vertebrate Paleontology. - 0272-4634 .- 1937-2809.
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Tidskriftsartikel (refereegranskat)abstract
- A new early Miocene large castorid, Minocastor godai gen. et sp. nov., from the Dota locality, Gifu Prefecture in central Japan, is described on the basis of dentaries and teeth. The material comes from the Kani basin, where limnofluviatile clay and sandstones of the Nakamura Formation (Mizunami Group) are exposed on the southern (left) bank of the Kiso River. It represents the richest sample of a Miocene small mammal in the Japanese fossil record thus far known. Based on jaw and tooth morphology, this new castorid most likely represents a primitive anchitheriomyine. However, it lacks the marked striations on the incisors that are characteristic of the advanced large, middle Miocene anchitheriomyines like Anchitheriomys and Amblycastor. The new castorid shares this dental feature with other primitive anchitheriomyines from Asia and North America, like Propalaeocastor, Oligotheriomys, and Miotheriomys. For these genera, a new tribe, Minocastorini, is proposed as sister group to the Anchitheriomyini. The incisor enamel microstructure of the new castorid largely exhibits plesiomorphic characters but also apomorphic features such as pseudo-pauciserial Hunter-Schreger bands. Additionally, the outer portion of the enamel band is rather thick in comparison to that of other beavers. Based on the rodent taxa associated with Minocastor godai gen. et sp. nov., Dota can be correlated with European Neogene mammal units MN 3/4. Magnetostratigraphic studies and radiometric dates obtained from the Mizunami Group indicate that Dota is more likely correlated with MN 3, with an absolute age of around 18.5 Ma.
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| 35. |
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| 36. |
- Novas, Fernando E., et al.
(författare)
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A new large pterosaur from the Late Cretaceous of Patagonia
- 2012
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Ingår i: Journal of Vertebrate Paleontology. - UK : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 32:6, s. 1447-1452
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Tidskriftsartikel (refereegranskat)abstract
- Here, we expand the meager record of Late Cretaceous South American pterosaurs with the description of a partial rostrum belonging to a large azhdarchid pterodactyloid. The specimen was collected close to the Bajo de Arriagada locality, corresponding to the uppermost Cretaceous Allen Formation of Argentina, around 80 km northwest of the well-sampled Bajo de Santa Rosa locality. The specimen represents the first unambiguous evidence of an azhdarchid pterosaur from South America. This specimen represents a new genus and species, Aerotitan sudamericanus, which is diagnosed based ona unique combination of characters, including one autapomorphy,and represents one of the largest known South Americanpterosaurs. The fossil here described resulted from a joint Argentine-Swedish paleontological expedition to Patagonia.
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| 37. |
- Olive, Sebastien, et al.
(författare)
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A new species of Groenlandaspis Heintz, 1932 (Placodermi, Arthrodira), from the Famennian (Late Devonian) of Belgium
- 2015
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 35:4
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Tidskriftsartikel (refereegranskat)abstract
- A new species of the phlyctaeniid arthrodire genus Groenlandaspis from the upper Famennian of Belgium is described. The remains of Groenlandaspis potyi, sp. nov., consist of dissociated thoracic armor elements, but the specimen designated to be the holotype displays the median dorsal, anterior, and posterior dorsolateral plates in articulation. Though incomplete, the new species is characterized by an equilateral triangle-shaped median dorsal plate, a protruding posterodorsal apron of the posterior dorsolateral plate behind the overlap area for the median dorsal plate, and an overall lack of ornamentation. Groenlandaspis potyi, sp. nov., constitutes the second occurrence of a Groenlandaspis species in continental Europe after the description of Groenlandaspis thorezi from upper Famennian quarries of Belgium. Another probable new species of Groenlandaspis is also described, though of unknown locality and horizon; it can, however, be deduced to be from the upper Famennian of Belgium without more precision. Together with some unpublished material of groenlandaspidids from the Famennian tetrapod-bearing locality of Strud, this material highlights the richness of Groenlandaspididae diversity in Belgium. The discovery of Groenlandaspis potyi, sp. nov., in Belgium reinforces the Famennian global distribution of this genus during this period. Also, because these organisms have been considered as non-marine indicators, this material is another argument pleading for close relationships between Euramerica and Gondwana around the Frasnian-Famennian boundary.
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| 38. |
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| 39. |
- Sachs, Sven, et al.
(författare)
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A New Basal Elasmosaurid (Sauropterygia: Plesiosauria) From The Lower Cretaceous Of Germany
- 2017
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 37:4
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Tidskriftsartikel (refereegranskat)abstract
- Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.
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| 40. |
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| 41. |
- Scheyer, Torsten M., et al.
(författare)
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First Record Of Soft-Shelled Turtles (Cryptodira, Trionychidae) From The Late Cretaceous Of Europe
- 2012
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 32:5, s. 1027-1032
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Tidskriftsartikel (refereegranskat)abstract
- Fossil soft-shelled turtles (Trionychidae) have so far been recognized in all continents except Antarctica, based largely on remains preserving their diagnostic sculptured shell bones. The origin of the group is generally assumed to be in the Early Cretaceous of Asia, whereas they first appear in North America and Europe during the Late Cretaceous and Paleocene, respectively. Here we describe the first record of an indeterminate trionychid from the late early Campanian from southern Sweden, a part of the paleobiogeographically isolated Fenno-Scandian Shield, thus extending the stratigraphic record of the group in Europe back about 15 Ma into the Late Cretaceous. Our finding provides evidence against the currently favored dispersal scenario in which trionychid turtles are interpreted to have come to Europe first during the Paleocene either directly from North America or via Asia. The described indeterminate trionychid possibly represents a relic of a pre-Cretaceous endemic radiation of North European trionychids living mainly on the Fenno-Skandian Shield or it may indicate a potential lower latitude dispersal route of trionychids from Asia to North America via Europe during the Late Cretaceous.
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| 42. |
- Slodownik, Miriam A., et al.
(författare)
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Reassessment of the Early Triassic trematosaurid temnospondyl Tertrema acuta from the Arctic island of Spitsbergen
- 2021
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Ingår i: Journal of Vertebrate Paleontology. - : Informa UK Limited. - 0272-4634 .- 1937-2809. ; 41:1
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Tidskriftsartikel (refereegranskat)abstract
- Trematosaurids were globally distributed Early Triassic temnospondyl amphibians characterized by elongate ‘crocodile-like’ skulls. Some of the most famous trematosaurid fossils were discovered on the island of Spitsbergen in the Arctic Svalbard archipelago. Among these, the short-snouted trematosaurine, Tertrema acuta, is one of the few taxa represented by virtually complete cranial remains. Unusually, however, the type specimens comprise only natural molds that were historically used to reconstruct three-dimensional casts. Here, we re-assess these restorations using the original impressions to phylogenetically analyze and re-diagnose the taxon. Unexpectedly, our first-hand scores differ markedly from previous literature-sourced interpretations and yield conflicting tree topologies that nest T. acuta with long-snouted lonchorhynchines, thus destabilizing the long-favored sub-division of trematosaurids based on their skull shape. We attribute this result to character state conflict and suggest that the traditional classification of trematosaurids may mask more complex evolutionary relationships, as well as possible trophic partitioning, and eco-morphological plasticity.
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| 43. |
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| 44. |
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| 45. |
- Vlachos, Evangelos, et al.
(författare)
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Late Miocene tortoises from Samos, Greece : implications for European Neogene testudinid systematics and distributions
- 2019
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Ingår i: Journal of Vertebrate Paleontology. - : Taylor & Francis. - 0272-4634 .- 1937-2809. ; 39:6
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Tidskriftsartikel (refereegranskat)abstract
- The world-famous upper Miocene fossil localities on the Aegean island of Samos in Greece have produced a rich fossil record that sheds light on the evolution of eastern Mediterranean terrestrial faunas over a one-million-year interval of the late Neogene. Fossils have been discovered on Samos since antiquity, although a succession of paleontological and commercial collecting expeditions over the last 130 years has resulted in specimens now being distributed throughout museums all over the world. Here, we survey the fossil tortoise remains from Samos, which are significant because they include early antecedents of the modern Testudo lineage, together with spectacular examples of the European Neogene gigantic testudinid †Titanochelon, which represents one of the largest-bodied terrestrial turtle taxa documented to date. All of the Samos fossils derive from the Mytilinii Formation, which spans the late MN11–early MN13 Neogene land mammal zones. The small-bodied tortoise remains include two incomplete shells that are morphologically consistent with basal testudonans and phylogenetically distinct from the coeval species Testudo marmorum found on mainland Greece. The Samos gigantic tortoise †‘Testudo’ schafferi was based on a spectacularly large skull and femur. However, we describe new plastron fragments, limb elements, and osteoderms that are compatible with †Titanochelon specimens from southern Greece and Anatolia. This could imply faunal links with the distinctive ‘Pikermian’ local assemblages from Asia Minor and concurs with the proposed late Miocene–Pliocene biogeographic segregation of large mammals from the eastern Aegean margin and Turkey relative to those occurring in northwestern Greece and the Balkan Peninsula.
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| 46. |
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| 47. |
- Werdelin, Lars, et al.
(författare)
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New species of Crocuta from the Early Pliocene of Kenya, with an overview of early Pliocene hyenas of eastern Africa
- 2008
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Ingår i: Journal of Vertebrate Paleontology. - 0272-4634 .- 1937-2809. ; 28, s. 1162-1170
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Tidskriftsartikel (refereegranskat)abstract
- A new species of Crocuta (spotted hyenas), Crocuta eturono n. sp., from the Early Pliocene of the Turkana Basin, Kenya is described. The species has been recovered from LO6S, a site in the Kataboi Member of the Nachukui Formation, on the western side of Lake Turkana. The site is dated to >3.4 Ma. The new species differs from all previously identified species of Crocuta in its length proportions of the cheek teeth, having a very long m1 and short p3 and p4. The species is also tentatively identified from the Tulu Bor Member of the Koobi Fora Formation, east side of Lake Turkana. The new species provides information for a discussion of the structure of the hyena guild in eastern Africa 4–3 Ma. Three groups of taxa are identified with distinct distributions. It is hypothesized that specific ecomorphologies of each group account for these distinctions.
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| 48. |
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| 49. |
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