J. Witts, N. Landman, M. Garb, Kayla M. Irizarry, E. Larina, N. Thibault, Mohammad Javad Razmjooei, T. Yancey, C. Myers
ABSTRACT We report on new collections of cephalopods (ammonites and nautilids) from the Cretaceous-Paleogene (K-Pg) successions of the Corsicana and Kincaid formations exposed along the Brazos River in Falls County, Texas. An abundant fauna of eight species comprising four genera of ammonites is described from the Corsicana Formation, including Discoscaphites mullinaxorum n. sp. The presence of abundant aptychi (probably lower jaws) of Discoscaphites and Eubaculites, as well as juvenile specimens, indicates a living population that experienced little postmortem drift. The lytoceratid genus Gaudryceras is also reported for the first time from the Brazos River area. Presence of the index taxon Discoscaphites iris (Conrad, 1858) indicates that the fauna belongs to the D. iris Range Zone, the highest ammonite range zone in North America. Correlation with new and existing microfossil data indicates that the fauna represents the uppermost Maastrichtian, and comparison with published records further suggests that this is the most diverse D. iris Zone fauna yet reported from the Gulf and Atlantic Coastal Plains of North America. Three ammonite genera are recorded from the basal units of the K-Pg event deposit at Brazos, which likely represents deposition in the immediate aftermath of the Chicxulub impact event. A single specimen of the nautilid Eutrephoceras is reported from the Danian Kincaid Formation, less than 300 kyr after the K-Pg boundary. These data provide new information on the differing fate of these cephalopod groups during the K-Pg mass extinction and add to the picture of diverse and abundant Maastrichtian ammonite faunas prior to the Chicxulub impact event.
{"title":"Cephalopods from the Cretaceous-Paleogene (K-Pg) Boundary Interval on the Brazos River, Texas, and Extinction of the Ammonites","authors":"J. Witts, N. Landman, M. Garb, Kayla M. Irizarry, E. Larina, N. Thibault, Mohammad Javad Razmjooei, T. Yancey, C. Myers","doi":"10.1206/3964.1","DOIUrl":"https://doi.org/10.1206/3964.1","url":null,"abstract":"ABSTRACT We report on new collections of cephalopods (ammonites and nautilids) from the Cretaceous-Paleogene (K-Pg) successions of the Corsicana and Kincaid formations exposed along the Brazos River in Falls County, Texas. An abundant fauna of eight species comprising four genera of ammonites is described from the Corsicana Formation, including Discoscaphites mullinaxorum n. sp. The presence of abundant aptychi (probably lower jaws) of Discoscaphites and Eubaculites, as well as juvenile specimens, indicates a living population that experienced little postmortem drift. The lytoceratid genus Gaudryceras is also reported for the first time from the Brazos River area. Presence of the index taxon Discoscaphites iris (Conrad, 1858) indicates that the fauna belongs to the D. iris Range Zone, the highest ammonite range zone in North America. Correlation with new and existing microfossil data indicates that the fauna represents the uppermost Maastrichtian, and comparison with published records further suggests that this is the most diverse D. iris Zone fauna yet reported from the Gulf and Atlantic Coastal Plains of North America. Three ammonite genera are recorded from the basal units of the K-Pg event deposit at Brazos, which likely represents deposition in the immediate aftermath of the Chicxulub impact event. A single specimen of the nautilid Eutrephoceras is reported from the Danian Kincaid Formation, less than 300 kyr after the K-Pg boundary. These data provide new information on the differing fate of these cephalopod groups during the K-Pg mass extinction and add to the picture of diverse and abundant Maastrichtian ammonite faunas prior to the Chicxulub impact event.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 52"},"PeriodicalIF":1.5,"publicationDate":"2021-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47835738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Alavesia has been known on the basis of five species in Late Cretaceous amber from Spain and Myanmar and two extant species from Namibia. Very recently, another extant species has been found in southern Brazil. Here we present a surprising diversity of Alavesia flies from the mid-Cretaceous of Myanmar (Late Albian-Early Cenomanian, ca. 99 Ma), including nine new species: A. angusta, sp. nov., A. brevipennae, sp. nov., A. lanceolata, sp. nov., A. latala, sp. nov., A. longicornuta, sp. nov., A. magna, sp. nov., A. pankowskiorum, sp. nov., A. spinosa, sp. nov., and A. zigrasi, sp. nov. The following new synonymy is proposed: Neoalavesia Poinar and Vega, 2020 = Alavesia Waters and Arillo, 1999. Notes are provided on an unusual structure, leg furrows found on femora to varying degrees among species, sometimes on tibiae, as well as notes on swarming behavior. Alavesia has undergone extensive extinction, a finding that further supports the relict nature of this genus and helps to explain the distribution of the other four Recent genera of Atelestidae, found in south and north temperate regions. Relict arthropod taxa preserved in Burmese amber are briefly reviewed, which also are narrowly endemic to temperate regions today.
{"title":"Cretaceous Diversity of the Relict Genus Alavesia Waters and Arillo (Diptera: Empidoidea: Atelestidae)","authors":"B. Sinclair, D. Grimaldi","doi":"10.1206/3961.1","DOIUrl":"https://doi.org/10.1206/3961.1","url":null,"abstract":"ABSTRACT Alavesia has been known on the basis of five species in Late Cretaceous amber from Spain and Myanmar and two extant species from Namibia. Very recently, another extant species has been found in southern Brazil. Here we present a surprising diversity of Alavesia flies from the mid-Cretaceous of Myanmar (Late Albian-Early Cenomanian, ca. 99 Ma), including nine new species: A. angusta, sp. nov., A. brevipennae, sp. nov., A. lanceolata, sp. nov., A. latala, sp. nov., A. longicornuta, sp. nov., A. magna, sp. nov., A. pankowskiorum, sp. nov., A. spinosa, sp. nov., and A. zigrasi, sp. nov. The following new synonymy is proposed: Neoalavesia Poinar and Vega, 2020 = Alavesia Waters and Arillo, 1999. Notes are provided on an unusual structure, leg furrows found on femora to varying degrees among species, sometimes on tibiae, as well as notes on swarming behavior. Alavesia has undergone extensive extinction, a finding that further supports the relict nature of this genus and helps to explain the distribution of the other four Recent genera of Atelestidae, found in south and north temperate regions. Relict arthropod taxa preserved in Burmese amber are briefly reviewed, which also are narrowly endemic to temperate regions today.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 40"},"PeriodicalIF":1.5,"publicationDate":"2020-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47783403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT A first known extant Neotropical species of the atelestid genus Alavesia—Alavesia leukoprosopa, sp. nov.—is described from southeastern Brazil. The holotype (and only specimen so far) was collected with a Malaise trap in an area with strongly impacted semideciduous seasonal forest (dry forest) and open, entirely secondary vegetation. It was collected in mid spring, but has not been collected again so far. Alavesia leukoprosopa shares some derived features with the only two other extant species of the genus, known from the Brandberg Massif in Namibia, suggesting that all three extant species may compose together a small clade separate from the bulk of the Cretaceous diversity of Alavesia.
{"title":"First Known Extant Species of Alavesia (Diptera: Atelestidae) in the Neotropical Region: Alavesia leukoprosopa, sp. nov., from the Southern Atlantic Forest, Brazil","authors":"Dalton De Souza Amorim, P. Riccardi, J. A. Rafael","doi":"10.1206/3962.1","DOIUrl":"https://doi.org/10.1206/3962.1","url":null,"abstract":"ABSTRACT A first known extant Neotropical species of the atelestid genus Alavesia—Alavesia leukoprosopa, sp. nov.—is described from southeastern Brazil. The holotype (and only specimen so far) was collected with a Malaise trap in an area with strongly impacted semideciduous seasonal forest (dry forest) and open, entirely secondary vegetation. It was collected in mid spring, but has not been collected again so far. Alavesia leukoprosopa shares some derived features with the only two other extant species of the genus, known from the Brandberg Massif in Namibia, suggesting that all three extant species may compose together a small clade separate from the bulk of the Cretaceous diversity of Alavesia.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 12"},"PeriodicalIF":1.5,"publicationDate":"2020-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48150715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Phylogenetic analyses of molecular sequence data obtained from the holotype of Marmosa regina Thomas, 1898, together with a reassessment of its morphological characters indicate that this species does not belong to the subgenus Micoureus as previously believed. Instead, both molecular and phenotypic data are consistent with the hypothesis that M. regina is a senior synonym of M. isthmica Goldman, 1912, in the subgenus Exulomarmosa. Because replacing isthmica with regina would create nomenclatural confusion, we recommend maintaining current usage of the former name and suppressing usage of the latter.
{"title":"On the Identity of Victoria's Mouse Opossum, Marmosa regina Thomas, 1898","authors":"Thomas C. Giarla, R. Voss","doi":"10.1206/3960.1","DOIUrl":"https://doi.org/10.1206/3960.1","url":null,"abstract":"ABSTRACT Phylogenetic analyses of molecular sequence data obtained from the holotype of Marmosa regina Thomas, 1898, together with a reassessment of its morphological characters indicate that this species does not belong to the subgenus Micoureus as previously believed. Instead, both molecular and phenotypic data are consistent with the hypothesis that M. regina is a senior synonym of M. isthmica Goldman, 1912, in the subgenus Exulomarmosa. Because replacing isthmica with regina would create nomenclatural confusion, we recommend maintaining current usage of the former name and suppressing usage of the latter.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 13"},"PeriodicalIF":1.5,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41656749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The Neotropical genus Camarochilus Harris, 1930 (Hemiptera: Pachynomidae) was described based on two species from Panama and Brazil. The genus has not been revised since its original treatment, and specimens beyond the original type series have remained undocumented. Based on examination of 57 specimens, including holotypes or paratypes of the previously described species, we here revise Camarochilus and recognize 10 species, with eight described as new: C. fasciatus, n. sp., C. gilli, n. sp., C. globosus, n. sp., C. harrisi, n. sp., C. medius, n. sp., C. picturatus, n. sp., C. robustus, n. sp., and C. tenuis, n. sp. Habitus images are provided for all species, male and female genitalic structures are documented, and various morphological characters are illustrated using digital photography. Measurements are included for all species. Male genitalic characters including the degree of asymmetry and type of ornamentation of the pygophore and shape of parameres constitute important species-diagnostic features, in addition to coloration and measurements. Distribution maps illustrate that species occur from Bolivia to Honduras, a considerable expansion of the previously known species distribution ranges in this genus.
{"title":"Taxonomic Revision of Camarochilus Harris (Hemiptera: Pachynomidae)","authors":"C. Weirauch, D. Forero, R. Schuh","doi":"10.1206/3959.1","DOIUrl":"https://doi.org/10.1206/3959.1","url":null,"abstract":"ABSTRACT The Neotropical genus Camarochilus Harris, 1930 (Hemiptera: Pachynomidae) was described based on two species from Panama and Brazil. The genus has not been revised since its original treatment, and specimens beyond the original type series have remained undocumented. Based on examination of 57 specimens, including holotypes or paratypes of the previously described species, we here revise Camarochilus and recognize 10 species, with eight described as new: C. fasciatus, n. sp., C. gilli, n. sp., C. globosus, n. sp., C. harrisi, n. sp., C. medius, n. sp., C. picturatus, n. sp., C. robustus, n. sp., and C. tenuis, n. sp. Habitus images are provided for all species, male and female genitalic structures are documented, and various morphological characters are illustrated using digital photography. Measurements are included for all species. Male genitalic characters including the degree of asymmetry and type of ornamentation of the pygophore and shape of parameres constitute important species-diagnostic features, in addition to coloration and measurements. Distribution maps illustrate that species occur from Bolivia to Honduras, a considerable expansion of the previously known species distribution ranges in this genus.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 31"},"PeriodicalIF":1.5,"publicationDate":"2020-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48032660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thiago Borges Fernandes Semedo, M. N. D. Da Silva, E. Gutiérrez, D. C. Ferreira, Mario Da Silva Nunes, A. C. Mendes-Oliveira, I. Farias, R. Rossi
ABSTRACT Species of Neacomys are small cricetid rodents that occur in forested habitats of Central and South America, from eastern Panama to central Bolivia and central/western Brazil. In order to assess species diversity of this poorly known genus, we obtained cytochrome b gene sequences from the most comprehensive taxonomic and geographic sampling analyzed to date. We also conducted morphological analyses on a large series of specimens housed in 15 museums, including types of 10 out of 14 nominal taxa. Our analyses of the genetic data recovered 17 lineages clustered in four distinct clades. Among these lineages, 11 correspond to species currently recognized as valid, and the remaining six are putative new species. In southeastern Amazonia—the geographical scope of this report—four undescribed species were discovered, three of which are named herein: Neacomys marajoara, sp. nov., from the Island of Marajó, Pará state; Neacomys vossi, sp. nov., restricted to the Tapajós center of endemism (between the Tapajós and Xingu rivers); and Neacomys xingu, sp. nov., restricted to the Xingu center of endemism (between the Xingu and Araguaia/Tocantins rivers). The new species can be discriminated from other Neacomys species by the morphology of the nasal bones, zygomatic plate, interorbital region, subsquamosal fenestra, paraoccipital process, incisive foramina, auditory bullae, anterocone and anteroloph of the first upper molar, carotid circulation pattern, and karyotype. Our results substantially improve our understanding of the genus Neacomys by providing morphological, morphometric, and novel molecular insights about these poorly known rodents and demonstrate that the diversity of small Amazonian mammals is still poorly known, even in the relatively accessible southeastern part of the biome.
{"title":"Systematics of Neotropical Spiny Mice, Genus Neacomys Thomas, 1900 (Rodentia: Cricetidae), from Southeastern Amazonia, with Descriptions of Three New Species","authors":"Thiago Borges Fernandes Semedo, M. N. D. Da Silva, E. Gutiérrez, D. C. Ferreira, Mario Da Silva Nunes, A. C. Mendes-Oliveira, I. Farias, R. Rossi","doi":"10.1206/3958.1","DOIUrl":"https://doi.org/10.1206/3958.1","url":null,"abstract":"ABSTRACT Species of Neacomys are small cricetid rodents that occur in forested habitats of Central and South America, from eastern Panama to central Bolivia and central/western Brazil. In order to assess species diversity of this poorly known genus, we obtained cytochrome b gene sequences from the most comprehensive taxonomic and geographic sampling analyzed to date. We also conducted morphological analyses on a large series of specimens housed in 15 museums, including types of 10 out of 14 nominal taxa. Our analyses of the genetic data recovered 17 lineages clustered in four distinct clades. Among these lineages, 11 correspond to species currently recognized as valid, and the remaining six are putative new species. In southeastern Amazonia—the geographical scope of this report—four undescribed species were discovered, three of which are named herein: Neacomys marajoara, sp. nov., from the Island of Marajó, Pará state; Neacomys vossi, sp. nov., restricted to the Tapajós center of endemism (between the Tapajós and Xingu rivers); and Neacomys xingu, sp. nov., restricted to the Xingu center of endemism (between the Xingu and Araguaia/Tocantins rivers). The new species can be discriminated from other Neacomys species by the morphology of the nasal bones, zygomatic plate, interorbital region, subsquamosal fenestra, paraoccipital process, incisive foramina, auditory bullae, anterocone and anteroloph of the first upper molar, carotid circulation pattern, and karyotype. Our results substantially improve our understanding of the genus Neacomys by providing morphological, morphometric, and novel molecular insights about these poorly known rodents and demonstrate that the diversity of small Amazonian mammals is still poorly known, even in the relatively accessible southeastern part of the biome.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 43"},"PeriodicalIF":1.5,"publicationDate":"2020-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66160930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Russell K. Engelman, J. J. Flynn, A. Wyss, D. Croft
ABSTRACT Thylacosmiline sparassodonts (previously recognized as thylacosmilids) are among the most iconic groups of endemic South American Cenozoic mammals due to their distinctive morphology and convergent resemblance to saber-toothed placental carnivores. However, the early evolution of this group and its relationship to other sparassodonts remains poorly understood, primarily because only highly specialized Neogene taxa such as Thylacosmilus, Anachlysictis, and Patagosmilus are well known. Here, we describe a new Paleogene sparassodont, Eomakhaira molossus, from the Cachapoal locality of central Chile, the first sparassodont reported from early Oligocene strata of the Abanico Formation. Eomakhaira shares features with both Neogene thylacosmilines and Paleogene “proborhyaenids,” and phylogenetic analyses recover this taxon as sister to the clade of Patagosmilus + Thylacosmilus. This broader clade, in turn, is nested within the group conventionally termed Proborhyaenidae. Our analyses support prior hypotheses of a close relationship between thylacosmilines and traditionally recognized proborhyaenids and provide the strongest evidence to date that thylacosmilines are proborhyaenids (i.e, the latter name as conventionally used refers to a paraphyletic group). To reflect the internestedness of these taxa, we propose use of Riggs' (1933) original name Thylacosmilinae for the less inclusive grouping and Proborhyaenidae for the more inclusive one. Saber teeth arose just once among metatherians (among thylacosmilines), perhaps reflecting a developmental constraint related to nonreplacement of canines in metatherians; hypselodonty may have relaxed this potential constraint in thylacosmilines. The occurrence of Eomakhaira in strata of early Oligocene age from the Chilean Andes demonstrates that the stratigraphic range of thylacosmilines spanned almost 30 million years, far surpassing those of saber-toothed placental lineages.
{"title":"Eomakhaira molossus, A New Saber-Toothed Sparassodont (Metatheria: Thylacosmilinae) from the Early Oligocene (?Tinguirirican) Cachapoal Locality, Andean Main Range, Chile","authors":"Russell K. Engelman, J. J. Flynn, A. Wyss, D. Croft","doi":"10.1206/3957.1","DOIUrl":"https://doi.org/10.1206/3957.1","url":null,"abstract":"ABSTRACT Thylacosmiline sparassodonts (previously recognized as thylacosmilids) are among the most iconic groups of endemic South American Cenozoic mammals due to their distinctive morphology and convergent resemblance to saber-toothed placental carnivores. However, the early evolution of this group and its relationship to other sparassodonts remains poorly understood, primarily because only highly specialized Neogene taxa such as Thylacosmilus, Anachlysictis, and Patagosmilus are well known. Here, we describe a new Paleogene sparassodont, Eomakhaira molossus, from the Cachapoal locality of central Chile, the first sparassodont reported from early Oligocene strata of the Abanico Formation. Eomakhaira shares features with both Neogene thylacosmilines and Paleogene “proborhyaenids,” and phylogenetic analyses recover this taxon as sister to the clade of Patagosmilus + Thylacosmilus. This broader clade, in turn, is nested within the group conventionally termed Proborhyaenidae. Our analyses support prior hypotheses of a close relationship between thylacosmilines and traditionally recognized proborhyaenids and provide the strongest evidence to date that thylacosmilines are proborhyaenids (i.e, the latter name as conventionally used refers to a paraphyletic group). To reflect the internestedness of these taxa, we propose use of Riggs' (1933) original name Thylacosmilinae for the less inclusive grouping and Proborhyaenidae for the more inclusive one. Saber teeth arose just once among metatherians (among thylacosmilines), perhaps reflecting a developmental constraint related to nonreplacement of canines in metatherians; hypselodonty may have relaxed this potential constraint in thylacosmilines. The occurrence of Eomakhaira in strata of early Oligocene age from the Chilean Andes demonstrates that the stratigraphic range of thylacosmilines spanned almost 30 million years, far surpassing those of saber-toothed placental lineages.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 75"},"PeriodicalIF":1.5,"publicationDate":"2020-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49070443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT In 1934, Barnum Brown of the American Museum of Natural History in New York (AMNH) led a large-scale dinosaur excavation in northern Wyoming, where he had found bones two years earlier. Initially, Brown expected to excavate two skeletons of sauropod dinosaurs, but soon after opening the quarry, the team realized that the site far exceeded their expectations: in the end, they unearthed approximately 3000 bones within six months and sent approximately 144 crates back to the AMNH. Due to the enormous number of bones, the site became world famous as a dinosaur graveyard, and media from all over the United States and abroad reported on the expedition. Soon after, however, the collection shifted away from a curatorial focus. What followed was a history of neglect: inappropriate storage conditions, water and fire damage, collapsing wooden boxes, and deteriorating plaster jackets. Relocation and further excavation of the quarry by the Sauriermuseum Aathal (Switzerland; SMA) from 1989 to 1991 confirmed earlier finds of skin impressions and resulted in the recognition of a novel diplodocid sauropod: Kaatedocus siberi. Given that the amount of bones found by the AMNH far exceeded those found by the SMA, a new project was started in 2017 to reassess the state and scientific value of the historic collections at AMNH. Although most of the bones are heavily fragmented, preliminary results show that overall preservation is still exceptional. Here, we reconstruct the history of the excavation, as well as past conservation and preparation procedures, and provide a report of current efforts to prepare, conserve, and catalog the material that has remained in storage since the 1930s. These current efforts show that historic collections, even after decades of neglect, can be of great and unexpected value, both for research and scientific outreach.
{"title":"Reconstructing the Specimens and History of Howe Quarry (Upper Jurassic Morrison Formation; Wyoming)","authors":"E. Tschopp, C. Mehling, M. Norell","doi":"10.1206/3956.1","DOIUrl":"https://doi.org/10.1206/3956.1","url":null,"abstract":"ABSTRACT In 1934, Barnum Brown of the American Museum of Natural History in New York (AMNH) led a large-scale dinosaur excavation in northern Wyoming, where he had found bones two years earlier. Initially, Brown expected to excavate two skeletons of sauropod dinosaurs, but soon after opening the quarry, the team realized that the site far exceeded their expectations: in the end, they unearthed approximately 3000 bones within six months and sent approximately 144 crates back to the AMNH. Due to the enormous number of bones, the site became world famous as a dinosaur graveyard, and media from all over the United States and abroad reported on the expedition. Soon after, however, the collection shifted away from a curatorial focus. What followed was a history of neglect: inappropriate storage conditions, water and fire damage, collapsing wooden boxes, and deteriorating plaster jackets. Relocation and further excavation of the quarry by the Sauriermuseum Aathal (Switzerland; SMA) from 1989 to 1991 confirmed earlier finds of skin impressions and resulted in the recognition of a novel diplodocid sauropod: Kaatedocus siberi. Given that the amount of bones found by the AMNH far exceeded those found by the SMA, a new project was started in 2017 to reassess the state and scientific value of the historic collections at AMNH. Although most of the bones are heavily fragmented, preliminary results show that overall preservation is still exceptional. Here, we reconstruct the history of the excavation, as well as past conservation and preparation procedures, and provide a report of current efforts to prepare, conserve, and catalog the material that has remained in storage since the 1930s. These current efforts show that historic collections, even after decades of neglect, can be of great and unexpected value, both for research and scientific outreach.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 56"},"PeriodicalIF":1.5,"publicationDate":"2020-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45613162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Newly available molecular sequences and morphological data suggest that Philander nigratus Thomas, 1923, is a valid species. Currently known from just eight specimens collected in the Peruvian departments of Junín and Ayacucho, P. nigratus does not appear to be closely related to either of the congeneric taxa with which it was previously synonymized.
{"title":"A Revision of Philander (Marsupialia: Didelphidae), Part 2: Phylogenetic Relationships and Morphological Diagnosis of P. nigratus Thomas, 1923","authors":"R. Voss, Thomas C. Giarla","doi":"10.1206/3955.1","DOIUrl":"https://doi.org/10.1206/3955.1","url":null,"abstract":"ABSTRACT Newly available molecular sequences and morphological data suggest that Philander nigratus Thomas, 1923, is a valid species. Currently known from just eight specimens collected in the Peruvian departments of Junín and Ayacucho, P. nigratus does not appear to be closely related to either of the congeneric taxa with which it was previously synonymized.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 16"},"PeriodicalIF":1.5,"publicationDate":"2020-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47598547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Three-dimensional Late Cretaceous elasmobranch endoskeletal elements (including palatoquadrates, ceratohyals, braincase fragments, and a series of anterior vertebrae) are described from the Late Cretaceous University of Alabama Harrell Station Paleontological Site (HSPS), Dallas County, Alabama. The material is referred to the extant elasmobranch Family Squatinidae on the basis of several distinctive morphological features. It also exhibits features not shared by any modern or fossil Squatina species or the extinct Late Jurassic squatinid Pseudorhina. A new genus and species is erected, despite there being some uncertainty regarding potential synonymy with existing nominal species previously founded on isolated fossil teeth (curiously, no squatinid teeth have been documented from the HSPS). A preliminary phylogenetic analysis suggests that the new genus falls on the squatinid stem, phylogenetically closer to Squatina than Pseudorhina. The craniovertebral articulation in the new genus exhibits features considered convergent with modern batomorphs (skates and rays), including absence of contact between the posterior basicranium and first vertebral centrum, and a notochordal canal which fails to reach the parachordal basicranium. Supporting evidence that similarities in the craniovertebral articulation of squatinoids and batomorphs are convergent rather than synapomorphic (as “hypnosqualeans”) is presented by an undescribed Early Jurassic batomorph, in which an occipital hemicentrum articulates with the first vertebral centrum as in all modern sharklike (selachimorph) elasmobranchs. The fossil suggests instead that the batomorph synarcual evolved by fusion of the anterior basiventral and basidorsal cartilages prior to the reduction of the anterior centra and loss of the occipital hemicentrum, not afterward as predicted by the hypnosqualean hypothesis.
{"title":"A New Genus of Late Cretaceous Angel Shark (Elasmobranchii; Squatinidae), with Comments on Squatinid Phylogeny","authors":"J. Maisey, Dana J. Ehret, J. Denton","doi":"10.1206/3954.1","DOIUrl":"https://doi.org/10.1206/3954.1","url":null,"abstract":"ABSTRACT Three-dimensional Late Cretaceous elasmobranch endoskeletal elements (including palatoquadrates, ceratohyals, braincase fragments, and a series of anterior vertebrae) are described from the Late Cretaceous University of Alabama Harrell Station Paleontological Site (HSPS), Dallas County, Alabama. The material is referred to the extant elasmobranch Family Squatinidae on the basis of several distinctive morphological features. It also exhibits features not shared by any modern or fossil Squatina species or the extinct Late Jurassic squatinid Pseudorhina. A new genus and species is erected, despite there being some uncertainty regarding potential synonymy with existing nominal species previously founded on isolated fossil teeth (curiously, no squatinid teeth have been documented from the HSPS). A preliminary phylogenetic analysis suggests that the new genus falls on the squatinid stem, phylogenetically closer to Squatina than Pseudorhina. The craniovertebral articulation in the new genus exhibits features considered convergent with modern batomorphs (skates and rays), including absence of contact between the posterior basicranium and first vertebral centrum, and a notochordal canal which fails to reach the parachordal basicranium. Supporting evidence that similarities in the craniovertebral articulation of squatinoids and batomorphs are convergent rather than synapomorphic (as “hypnosqualeans”) is presented by an undescribed Early Jurassic batomorph, in which an occipital hemicentrum articulates with the first vertebral centrum as in all modern sharklike (selachimorph) elasmobranchs. The fossil suggests instead that the batomorph synarcual evolved by fusion of the anterior basiventral and basidorsal cartilages prior to the reduction of the anterior centra and loss of the occipital hemicentrum, not afterward as predicted by the hypnosqualean hypothesis.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2020 1","pages":"1 - 29"},"PeriodicalIF":1.5,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42135473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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