The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
... Figure 4.9). Russell Hawley's line drawings are generally well-crafted, aside from a few... more ... Figure 4.9). Russell Hawley's line drawings are generally well-crafted, aside from a few lapses (eg, Figure 7.9), and Dan Varner's necessarily speculative paintings of fish and marine reptiles are typically dynamic and engaging. ...
Transactions of The Kansas Academy of Science, Jan 1, 2005
The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
Large-bodied suspension feeders (planktivores), which include the most massive animals to have ev... more Large-bodied suspension feeders (planktivores), which include the most massive animals to have ever lived, are conspicuously absent from Mesozoic marine environments. The only clear representatives of this trophic guild in the Mesozoic have been an enigmatic and apparently short-lived Jurassic group of extinct pachycormid fishes. Here, we report several new examples of these giant bony fishes from Asia, Europe, and North America. These fossils provide the first detailed anatomical information on this poorly understood clade and extend its range from the lower Middle Jurassic to the end of the Cretaceous, showing that this group persisted for more than 100 million years. Modern large-bodied, planktivorous vertebrates diversified after the extinction of pachycormids at the Cretaceous-Paleogene boundary, which is consistent with an opportunistic refilling of vacated ecospace.
Kansas Academy of Science, Transactions 113(3-4):197-205, 2010
George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a... more George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a 2 m Gillicus preserved inside a 4 m Xiphactinus specimen, from the Late Cretaceous Smoky Hill Chalk of Gove County, Kansas in 1952. Another, much earlier collected “fish-within-a-fish” specimen was rediscovered recently in storage at Park University, Parkville, Missouri. It was collected by G.F. Sternberg’s father, Charles H. Sternberg, who sold it and other specimens to the university from his laboratory in Lawrence, Kansas. A letter dated March 24, 1919 accompanying the materials confirmed that the sale occurred just prior to the elder Sternberg moving to his retirement in California. Most importantly, this specimen is the only known example of Ichthyodectes ctenodon Cope 1870 with stomach contents. Although most of the prey fish was lost due to erosion prior to discovery, it has been tentatively identified as Enchodus petrosus from the characteristics of the caudal fin, vertebrae, and overall size. Due to the posterior location of the prey, it appears that the larger Ichthyodectes died after some digestion of the prey had taken place. Although I. ctenodon has long been assumed to be one of the major mid-sized predators in the Western Interior Sea, this specimen provides the first evidence of a piscivorous diet and adds to our knowledge of the ecology of the Late Cretaceous ocean that covered much the North American Midwest.
Abstract—The ptychodontid, Ptychodus mortoni, is a well-known species of Cretaceous durophagous s... more Abstract—The ptychodontid, Ptychodus mortoni, is a well-known species of Cretaceous durophagous shark. Many specimens assigned to the species have been collected from various Upper Cretaceous marine strata of North America. However, since the discovery of the holotype in the early 1800s in Alabama, the authorship of the specific name has been unclear, or at least, inconsistent in the literature. To date, it has most often been credited to “Louis Agassiz (1839–1843)”, but assignments to “Gideon Mantell (1836)” and “Samuel Morton (1834)” have also appeared. To evaluate the true authorship of P. mortoni, we reviewed Morton’s and Mantell’s papers, and Agassiz’s Recherches sur les Poissons Fossiles, as well as other key publications, especially those published in the 1800s and the early 1900s. In addition, a reexamination of the holotypic material at the Natural History Museum in London (NHMUK PV OR 28394) is presented. Based on our review of the available information, we conclude that “Mantell (1836)” should be the authorship of the species. This investigation of the naming of P. mortoni also sheds light on some personal interactions between Agassiz and Mantell who were important early contributors to paleontology.
A procoelous dorsal vertebra collected from the Hartland Shale Member of the Late Cretaceous Gree... more A procoelous dorsal vertebra collected from the Hartland Shale Member of the Late Cretaceous Greenhorn Formation represents the oldest specimen of a large squamate reptile, possibly a dolichosaur or early mosasauroid, from Kansas. The isolated vertebra was collected near the contact between the Hartland Shale and Jetmore Chalk (late Cenomanian - early Turonian) members of the Greenhorn Formation in Mitchell County, Kansas. A latest Cenomanian age was determined by analysis of the nannofossils contained in matrix recovered from the neural canal of the specimen. Key words: Dolichosauridae, Mosasauridae, procoelous, Hartland Shale, Jetmore Chalk, Cenomanian, Turonian. marine, Western Interior Seaway
"Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed t... more "Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed the highest number of cervical vertebrae for any known vertebrate. Historically, the largest count has been attributed to the iconic Elasmosaurus platyurus from the Late Cretaceous of Kansas, but estimates for the total neck series in this taxon have varied between published reports. Accurately determining the number of vertebral centra vis-a`-vis the maximum length of the neck in plesiosaurians has significant implications for phylogenetic character designations, as well as the inconsistent terminology applied to some osteological structures. With these issues in mind, we reassessed the holotype of E. platyurus as a model for standardizing the debated cervical-dorsal transition in plesiosaurians, and during this procedure, documented a ‘‘lost’’ cervical centrum. Our revision also advocates retention of the term ‘‘pectorals’’ to describe the usually three or more distinctive vertebrae close to the cranial margin of the forelimb girdle that bear a functional rib facet transected by the neurocentral suture, and thus conjointly formed by both the parapophysis on the centrum body and diapophysis from the neural arch (irrespective of rib length). This morphology is unambiguously distinguishable from standard cervicals, in which the functional rib facet is borne exclusively on the centrum, and dorsals in which the rib articulation is situated above the neurocentral suture and functionally borne only by the transverse process of the neural arch. Given these easily distinguishable definitions, the maximum number of neck vertebrae preserved in E. platyurus is 72; this is only three vertebrae shorter than the recently described Albertonectes, which together with E. platyurus constitute the ‘‘longest necked’’ animals ever to have lived."
George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a... more George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a 2 m Gillicus preserved inside a 4 m Xiphactinus specimen, from the Late Cretaceous Smoky Hill Chalk of Gove County, Kansas in 1952. Another, much earlier collected “fish-within-a-fish” specimen was rediscovered recently in storage at Park University, Parkville, Missouri. It was collected by G.F. Sternberg’s father, Charles H. Sternberg, who sold it and other specimens to the university from his laboratory in Lawrence, Kansas. A letter dated March 24, 1919 accompanying the materials confirmed that the sale occurred just prior to the elder Sternberg moving to his retirement in California. Most importantly, this specimen is the only known example of Ichthyodectes ctenodon Cope 1870 with stomach contents. Although most of the prey fish was lost due to erosion prior to discovery, it has been tentatively identified as Enchodus petrosus from the characteristics of the caudal fin, vertebrae, and overall size. Due to the posterior location of the prey, it appears that the larger Ichthyodectes died after some digestion of the prey had taken place. Although I. ctenodon has long been assumed to be one of the major mid-sized predators in the Western Interior Sea, this specimen provides the first evidence of a piscivorous diet and adds to our knowledge of the ecology of the Late Cretaceous ocean that covered much the North American Midwest.
The old “Fort Benton Group” (Middle Cenomanian to Middle Turonian) in central Kansas has produced... more The old “Fort Benton Group” (Middle Cenomanian to Middle Turonian) in central Kansas has produced a relatively large number of plesiosaur specimens. In modern terminology, this historical stratigraphic term refers to the Graneros Shale, Greenhorn Limestone, and Carlile Shale of the Western Interior. In particular, the Fairport Chalk Member of the Carlile Shale has produced an unusually high number of partial plesiosaur skeletons in light of the fact that it is characteristically poorly exposed and minimally accessible. Polycotylids, including Trinacromerum bentonianum, are first documented in central Kansas from the upper Hartland Shale Member, Greenhorn Limestone (middle Upper Cenomanian), and appear to be especially well represented in the upper Greenhorn Limestone and lower one-half of the Fairport Chalk (Lower and Middle Turonian). Pliosaurids, including Brachauchenius lucasi, are known from the basal Lincoln Limestone Member, Greenhorn Limestone (Middle Cenomanian) to the middle of the Fairport Chalk. The occurrence of pliosaurs in the Fairport Chalk (early Middle Turonian) is at or near the last known occurrence of this group prior to their extinction. Elasmosaurid remains are rare throughout the “Fort Benton” interval, with only three firmly established records from the Graneros Shale and Greenhorn Limestone (Middle Cenomanian to Early Turonian) in Kansas.
In June, 2008, the partial internal mold of a small ammonite was discovered beneath a Tylosaurus ... more In June, 2008, the partial internal mold of a small ammonite was discovered beneath a Tylosaurus nepaeolicus skull collected from the Clioscaphites vermiformis-C. choteauensis zone (early to mid-Santonian), Smoky Hill Chalk. in northern Lane County, Kansas by staff of the Rocky Mountain Dinosaur Resource Center. The specimen was collected and later donated to the Sternberg Museum of Natural History. The ammonite did not appear to be directly associated with the vertebrate remains. The mold preserves a trace of the siphuncle as distinct line visible for about 4 cm along near the outer edge of the specimen. Although incomplete, the specimen preserves the distinctive uncoiled form of a heteromorph ammonite, and appears to be quite similar to a species (Glyptoxoceras texanum) recently named from Santonian deposits in northeastern Texas. This specimen is the first known occurrence of a heteromorph ammonite in the Smoky Hill Chalk.
The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of
terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
The Niobrara Chalk in western Kansas was deposited on the eastern shelf of the Late Cretaceous We... more The Niobrara Chalk in western Kansas was deposited on the eastern shelf of the Late Cretaceous Western Interior Sea during Coniacian through early Campanian time, hundreds of miles from the nearest land. As might be expected, the remains of
terrestrial animals, including dinosaurs, are extremely rare in this marine environment. The first dinosaur (Claosaurus agilis) collected by Marsh from the Smoky Hill Chalk Member of the Niobrara Chalk in 1871 was also the only hadrosaur known from this formation. All other dinosaur remains collected there since 1871 have been identified as nodosaurs. Here we report the discovery of an articulated series of nine hadrosaur caudal vertebrae (FHSM VP-15824) from the Smoky Hill Chalk (upper Coniacian) of southeastern Gove County, Kansas. The presence of non-serrated bite marks on four of the vertebrae and the partially digested appearance of the proximal and distal ends of the series suggest that the vertebrae had been scavenged from the floating carcass of a dinosaur by a large shark, most likely Cretoxyrhina mantelli. The specimen represents the earliest known occurrence (Upper Coniacian) of the Hadrosauridae in the Smoky Hill Chalk, and preserves the earliest evidence of scavenging on dinosaur remains by a shark in the Western Interior Sea.
The skull of the nodosaurid Niobrarasaurus coleii (Mehl) is redescribed as the result of the disc... more The skull of the nodosaurid Niobrarasaurus coleii (Mehl) is redescribed as the result of the discovery of additional material, including the partially crushed braincase. The bone surface shows moderate remodeling, but not to the point of sutural obliteration. The snout section suggests a long, narrow skull more similar to Pawpawsaurus than the broader Edmontonia. Nevertheless, the skull differs from other nodosaurs in the ornamentation of the bone surface and trapezoidal outline of the occipital condyle in
posterior view.
The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
... Figure 4.9). Russell Hawley's line drawings are generally well-crafted, aside from a few... more ... Figure 4.9). Russell Hawley's line drawings are generally well-crafted, aside from a few lapses (eg, Figure 7.9), and Dan Varner's necessarily speculative paintings of fish and marine reptiles are typically dynamic and engaging. ...
Transactions of The Kansas Academy of Science, Jan 1, 2005
The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
Large-bodied suspension feeders (planktivores), which include the most massive animals to have ev... more Large-bodied suspension feeders (planktivores), which include the most massive animals to have ever lived, are conspicuously absent from Mesozoic marine environments. The only clear representatives of this trophic guild in the Mesozoic have been an enigmatic and apparently short-lived Jurassic group of extinct pachycormid fishes. Here, we report several new examples of these giant bony fishes from Asia, Europe, and North America. These fossils provide the first detailed anatomical information on this poorly understood clade and extend its range from the lower Middle Jurassic to the end of the Cretaceous, showing that this group persisted for more than 100 million years. Modern large-bodied, planktivorous vertebrates diversified after the extinction of pachycormids at the Cretaceous-Paleogene boundary, which is consistent with an opportunistic refilling of vacated ecospace.
Kansas Academy of Science, Transactions 113(3-4):197-205, 2010
George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a... more George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a 2 m Gillicus preserved inside a 4 m Xiphactinus specimen, from the Late Cretaceous Smoky Hill Chalk of Gove County, Kansas in 1952. Another, much earlier collected “fish-within-a-fish” specimen was rediscovered recently in storage at Park University, Parkville, Missouri. It was collected by G.F. Sternberg’s father, Charles H. Sternberg, who sold it and other specimens to the university from his laboratory in Lawrence, Kansas. A letter dated March 24, 1919 accompanying the materials confirmed that the sale occurred just prior to the elder Sternberg moving to his retirement in California. Most importantly, this specimen is the only known example of Ichthyodectes ctenodon Cope 1870 with stomach contents. Although most of the prey fish was lost due to erosion prior to discovery, it has been tentatively identified as Enchodus petrosus from the characteristics of the caudal fin, vertebrae, and overall size. Due to the posterior location of the prey, it appears that the larger Ichthyodectes died after some digestion of the prey had taken place. Although I. ctenodon has long been assumed to be one of the major mid-sized predators in the Western Interior Sea, this specimen provides the first evidence of a piscivorous diet and adds to our knowledge of the ecology of the Late Cretaceous ocean that covered much the North American Midwest.
Abstract—The ptychodontid, Ptychodus mortoni, is a well-known species of Cretaceous durophagous s... more Abstract—The ptychodontid, Ptychodus mortoni, is a well-known species of Cretaceous durophagous shark. Many specimens assigned to the species have been collected from various Upper Cretaceous marine strata of North America. However, since the discovery of the holotype in the early 1800s in Alabama, the authorship of the specific name has been unclear, or at least, inconsistent in the literature. To date, it has most often been credited to “Louis Agassiz (1839–1843)”, but assignments to “Gideon Mantell (1836)” and “Samuel Morton (1834)” have also appeared. To evaluate the true authorship of P. mortoni, we reviewed Morton’s and Mantell’s papers, and Agassiz’s Recherches sur les Poissons Fossiles, as well as other key publications, especially those published in the 1800s and the early 1900s. In addition, a reexamination of the holotypic material at the Natural History Museum in London (NHMUK PV OR 28394) is presented. Based on our review of the available information, we conclude that “Mantell (1836)” should be the authorship of the species. This investigation of the naming of P. mortoni also sheds light on some personal interactions between Agassiz and Mantell who were important early contributors to paleontology.
A procoelous dorsal vertebra collected from the Hartland Shale Member of the Late Cretaceous Gree... more A procoelous dorsal vertebra collected from the Hartland Shale Member of the Late Cretaceous Greenhorn Formation represents the oldest specimen of a large squamate reptile, possibly a dolichosaur or early mosasauroid, from Kansas. The isolated vertebra was collected near the contact between the Hartland Shale and Jetmore Chalk (late Cenomanian - early Turonian) members of the Greenhorn Formation in Mitchell County, Kansas. A latest Cenomanian age was determined by analysis of the nannofossils contained in matrix recovered from the neural canal of the specimen. Key words: Dolichosauridae, Mosasauridae, procoelous, Hartland Shale, Jetmore Chalk, Cenomanian, Turonian. marine, Western Interior Seaway
"Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed t... more "Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed the highest number of cervical vertebrae for any known vertebrate. Historically, the largest count has been attributed to the iconic Elasmosaurus platyurus from the Late Cretaceous of Kansas, but estimates for the total neck series in this taxon have varied between published reports. Accurately determining the number of vertebral centra vis-a`-vis the maximum length of the neck in plesiosaurians has significant implications for phylogenetic character designations, as well as the inconsistent terminology applied to some osteological structures. With these issues in mind, we reassessed the holotype of E. platyurus as a model for standardizing the debated cervical-dorsal transition in plesiosaurians, and during this procedure, documented a ‘‘lost’’ cervical centrum. Our revision also advocates retention of the term ‘‘pectorals’’ to describe the usually three or more distinctive vertebrae close to the cranial margin of the forelimb girdle that bear a functional rib facet transected by the neurocentral suture, and thus conjointly formed by both the parapophysis on the centrum body and diapophysis from the neural arch (irrespective of rib length). This morphology is unambiguously distinguishable from standard cervicals, in which the functional rib facet is borne exclusively on the centrum, and dorsals in which the rib articulation is situated above the neurocentral suture and functionally borne only by the transverse process of the neural arch. Given these easily distinguishable definitions, the maximum number of neck vertebrae preserved in E. platyurus is 72; this is only three vertebrae shorter than the recently described Albertonectes, which together with E. platyurus constitute the ‘‘longest necked’’ animals ever to have lived."
George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a... more George F. Sternberg is well remembered for collecting the famous “Fish-within-a-fish” specimen, a 2 m Gillicus preserved inside a 4 m Xiphactinus specimen, from the Late Cretaceous Smoky Hill Chalk of Gove County, Kansas in 1952. Another, much earlier collected “fish-within-a-fish” specimen was rediscovered recently in storage at Park University, Parkville, Missouri. It was collected by G.F. Sternberg’s father, Charles H. Sternberg, who sold it and other specimens to the university from his laboratory in Lawrence, Kansas. A letter dated March 24, 1919 accompanying the materials confirmed that the sale occurred just prior to the elder Sternberg moving to his retirement in California. Most importantly, this specimen is the only known example of Ichthyodectes ctenodon Cope 1870 with stomach contents. Although most of the prey fish was lost due to erosion prior to discovery, it has been tentatively identified as Enchodus petrosus from the characteristics of the caudal fin, vertebrae, and overall size. Due to the posterior location of the prey, it appears that the larger Ichthyodectes died after some digestion of the prey had taken place. Although I. ctenodon has long been assumed to be one of the major mid-sized predators in the Western Interior Sea, this specimen provides the first evidence of a piscivorous diet and adds to our knowledge of the ecology of the Late Cretaceous ocean that covered much the North American Midwest.
The old “Fort Benton Group” (Middle Cenomanian to Middle Turonian) in central Kansas has produced... more The old “Fort Benton Group” (Middle Cenomanian to Middle Turonian) in central Kansas has produced a relatively large number of plesiosaur specimens. In modern terminology, this historical stratigraphic term refers to the Graneros Shale, Greenhorn Limestone, and Carlile Shale of the Western Interior. In particular, the Fairport Chalk Member of the Carlile Shale has produced an unusually high number of partial plesiosaur skeletons in light of the fact that it is characteristically poorly exposed and minimally accessible. Polycotylids, including Trinacromerum bentonianum, are first documented in central Kansas from the upper Hartland Shale Member, Greenhorn Limestone (middle Upper Cenomanian), and appear to be especially well represented in the upper Greenhorn Limestone and lower one-half of the Fairport Chalk (Lower and Middle Turonian). Pliosaurids, including Brachauchenius lucasi, are known from the basal Lincoln Limestone Member, Greenhorn Limestone (Middle Cenomanian) to the middle of the Fairport Chalk. The occurrence of pliosaurs in the Fairport Chalk (early Middle Turonian) is at or near the last known occurrence of this group prior to their extinction. Elasmosaurid remains are rare throughout the “Fort Benton” interval, with only three firmly established records from the Graneros Shale and Greenhorn Limestone (Middle Cenomanian to Early Turonian) in Kansas.
In June, 2008, the partial internal mold of a small ammonite was discovered beneath a Tylosaurus ... more In June, 2008, the partial internal mold of a small ammonite was discovered beneath a Tylosaurus nepaeolicus skull collected from the Clioscaphites vermiformis-C. choteauensis zone (early to mid-Santonian), Smoky Hill Chalk. in northern Lane County, Kansas by staff of the Rocky Mountain Dinosaur Resource Center. The specimen was collected and later donated to the Sternberg Museum of Natural History. The ammonite did not appear to be directly associated with the vertebrate remains. The mold preserves a trace of the siphuncle as distinct line visible for about 4 cm along near the outer edge of the specimen. Although incomplete, the specimen preserves the distinctive uncoiled form of a heteromorph ammonite, and appears to be quite similar to a species (Glyptoxoceras texanum) recently named from Santonian deposits in northeastern Texas. This specimen is the first known occurrence of a heteromorph ammonite in the Smoky Hill Chalk.
The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Up... more The right ulna and radius of a small nodosaur were recovered from the Smoky Hill Chalk Member (Upper Santonian) of the Niobrara Formation in October, 2000. Based on the similarity of the specimen in comparison with the holotype of Niobrarasaurus coleii, and the relatively small size of the remains, the bones are considered to be those of a juvenile N. coleii. The presence of two parallel scratch marks on the distal shaft of the radius, and the partially digested appearance of the proximal and distal ends of both bones, suggest that the lower limb had been detached from the carcass as the result of scavenging, most likely by the large lamniform shark, Cretoxyrhina mantelli. Although the remains of
terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
The Niobrara Chalk in western Kansas was deposited on the eastern shelf of the Late Cretaceous We... more The Niobrara Chalk in western Kansas was deposited on the eastern shelf of the Late Cretaceous Western Interior Sea during Coniacian through early Campanian time, hundreds of miles from the nearest land. As might be expected, the remains of
terrestrial animals, including dinosaurs, are extremely rare in this marine environment. The first dinosaur (Claosaurus agilis) collected by Marsh from the Smoky Hill Chalk Member of the Niobrara Chalk in 1871 was also the only hadrosaur known from this formation. All other dinosaur remains collected there since 1871 have been identified as nodosaurs. Here we report the discovery of an articulated series of nine hadrosaur caudal vertebrae (FHSM VP-15824) from the Smoky Hill Chalk (upper Coniacian) of southeastern Gove County, Kansas. The presence of non-serrated bite marks on four of the vertebrae and the partially digested appearance of the proximal and distal ends of the series suggest that the vertebrae had been scavenged from the floating carcass of a dinosaur by a large shark, most likely Cretoxyrhina mantelli. The specimen represents the earliest known occurrence (Upper Coniacian) of the Hadrosauridae in the Smoky Hill Chalk, and preserves the earliest evidence of scavenging on dinosaur remains by a shark in the Western Interior Sea.
The skull of the nodosaurid Niobrarasaurus coleii (Mehl) is redescribed as the result of the disc... more The skull of the nodosaurid Niobrarasaurus coleii (Mehl) is redescribed as the result of the discovery of additional material, including the partially crushed braincase. The bone surface shows moderate remodeling, but not to the point of sutural obliteration. The snout section suggests a long, narrow skull more similar to Pawpawsaurus than the broader Edmontonia. Nevertheless, the skull differs from other nodosaurs in the ornamentation of the bone surface and trapezoidal outline of the occipital condyle in
posterior view.
Fossil shark teeth are common but are usually represented by shed examples and are seldom in asso... more Fossil shark teeth are common but are usually represented by shed examples and are seldom in associated or articulated groups. Complete dentition reconstruction from isolated teeth cannot be certain, even when large quantities are available from a single location and horizon. The Smoky Hill Chalk (Late Cretaceous) of western Kansas, U.S.A. has yielded a number of associated, and sometimes articulated, tooth sets of Cretoxyrhina mantelli Agassiz. Teeth from articulated sets are rarely removed from matrix which limits the understanding of positional characteristics to a single perspective. In this paper, we analyze and described an associated set of disarticulated Cretoxyrhina teeth. These teeth were arranged and compared with other disarticulated associated sets, then compared with a known articulated tooth set; resulting in a multi-perspective Cretoxyrhina tooth set. This reconstruction provides characteristics that permit upper and lower lateroposterior teeth to be differentiated and raise questions regarding the number of anterior tooth positions present.
Our analysis of vertebrate remains collected from a Cenomanian microsite in the Lincoln Limestone... more Our analysis of vertebrate remains collected from a Cenomanian microsite in the Lincoln Limestone, the basal-most member of the Greenhorn Formation in Russell County, Kansas, identifies ornithurine (sensu Chiappe, 1996) avian fossils. The specimens presented here are slightly younger than the oldest avian remains known from North America (from the Woodbine Formation, Texas) and of a similar age as the avians from the Asheville Formation in Saskatchewan, Canada. This find thus connects the extensive geographic range of the earliest North American birds from Saskatchewan south through central Kansas and on to Texas. The specimens discussed here are fragmentary, yet show features definitive of ornithurine birds. One specimen is attributable to Ichthyornis, whereas another preserves teeth characteristic of ornithurine birds. In addition to bird bones, the microsite yielded numerous bony fish remains, shark teeth, coniasaur vertebrae, and other lizard bones.
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Key words: Dolichosauridae, Mosasauridae, procoelous, Hartland Shale, Jetmore Chalk, Cenomanian, Turonian. marine, Western Interior Seaway
terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
terrestrial animals, including dinosaurs, are extremely rare in this marine environment. The first dinosaur (Claosaurus agilis) collected by Marsh from the Smoky Hill Chalk Member of the Niobrara Chalk in 1871 was also the only hadrosaur known from this formation. All other dinosaur remains collected there since 1871 have been identified as nodosaurs. Here we report the discovery of an articulated series of nine hadrosaur caudal vertebrae (FHSM VP-15824) from the Smoky Hill Chalk (upper Coniacian) of southeastern Gove County, Kansas. The presence of non-serrated bite marks on four of the vertebrae and the partially digested appearance of the proximal and distal ends of the series suggest that the vertebrae had been scavenged from the floating carcass of a dinosaur by a large shark, most likely Cretoxyrhina mantelli. The specimen represents the earliest known occurrence (Upper Coniacian) of the Hadrosauridae in the Smoky Hill Chalk, and preserves the earliest evidence of scavenging on dinosaur remains by a shark in the Western Interior Sea.
posterior view.
Key words: Dolichosauridae, Mosasauridae, procoelous, Hartland Shale, Jetmore Chalk, Cenomanian, Turonian. marine, Western Interior Seaway
terrestrial vertebrates are not unknown from sediments deposited in the Late Cretaceous Western Interior Sea, additional discoveries are infrequent and valuable sources of information regarding the terrestrial fauna of the time.
terrestrial animals, including dinosaurs, are extremely rare in this marine environment. The first dinosaur (Claosaurus agilis) collected by Marsh from the Smoky Hill Chalk Member of the Niobrara Chalk in 1871 was also the only hadrosaur known from this formation. All other dinosaur remains collected there since 1871 have been identified as nodosaurs. Here we report the discovery of an articulated series of nine hadrosaur caudal vertebrae (FHSM VP-15824) from the Smoky Hill Chalk (upper Coniacian) of southeastern Gove County, Kansas. The presence of non-serrated bite marks on four of the vertebrae and the partially digested appearance of the proximal and distal ends of the series suggest that the vertebrae had been scavenged from the floating carcass of a dinosaur by a large shark, most likely Cretoxyrhina mantelli. The specimen represents the earliest known occurrence (Upper Coniacian) of the Hadrosauridae in the Smoky Hill Chalk, and preserves the earliest evidence of scavenging on dinosaur remains by a shark in the Western Interior Sea.
posterior view.