Donald L. Lofgren, Clifford Y. Shen, Naomi N. Buday, Clarissa Ylagan, Kathryn Lofgren, R. Lai, Dakota D. Santana-Grace, Alan R. Tabrum
ABSTRACT Pipestone Springs Main Pocket (PSMP) (Renova Formation, Jefferson County, Montana) has yielded an unusually rich concentration of mostly small-bodied Chadronian (late Eocene) mammals. Coprolites are common at PSMP and indicate which taxa and skeletal elements were consumed, as well as provide insight as to which carnivore species were likely to have deposited their feces at the site. Two distinct coprolite groupings were recognized based on differences in diameter, morphology, and abundance of bone. The sample of larger coprolites ranges in diameter from 16–29 mm and lacks a distinct mode. Some of the larger coprolites contain bone, but if present, it is sparse, poorly preserved, and unidentifiable. The sample of smaller coprolites varies in diameter from 4–15 mm and has a prominent mode at 10–11 mm. Many of the smaller coprolites contain abundant bone that is often highly fragmented. Osteoderms, bone ends, or dental elements identified to taxon in smaller coprolites indicate that marsupials, lizards, lagomorphs, and rodents were prey of smaller PSMP carnivores. Most elements identified as lagomorph or rodent probably represent Palaeolagus temnodon and Ischyromys veterior based on their high abundance in surface collections. Undigested bone from disaggregated carnivore feces did contribute to the large number of small dentigerous elements recovered from surface collections at PSMP, but it probably was not a major source because only two smaller coprolites had an exposed partial dentary or maxilla. The remains of mammalian carnivores are comparatively rare at PSMP and nine taxa are described, 52% of which represent Hesperocyon gregarius and 21% Brachyrhynchocyon dodgei. If the percentage of surface collected specimens for each carnivore taxon at PSMP is a reflection of activity at the depositional site, most of the smaller coprolites probably represent Hes. gregarius. To test this hypothesis, the ratios between feces diameter and body mass, as well as average lower first molar, (m1), length and body mass in an extant canid were applied to m1s of Hes. gregarius and the smaller coprolites from PSMP. Results indicate a mass of 3.3 kg for the smaller PSMP carnivore and 2.9 kg for Hes. gregarius from PSMP, both similar to the mass of Hesperocyon based on skeletal material. Also, the mode of smaller diameter coprolites is more prominent than the mode of the diameter of feces from an extant canid, which suggests that most of the smaller PSMP coprolites represent the activity of a single species, in this case Hes. gregarius. Many larger coprolites at PSMP probably represent Br. dodgei based on its high relative abundance, but the lack of a prominent mode for the larger coprolites suggests that one or more other species also contributed to the sample.
{"title":"Coprolites and Mammalian Carnivores from Pipestone Springs, Montana, and their Paleoecological Significance","authors":"Donald L. Lofgren, Clifford Y. Shen, Naomi N. Buday, Clarissa Ylagan, Kathryn Lofgren, R. Lai, Dakota D. Santana-Grace, Alan R. Tabrum","doi":"10.2992/007.084.0402","DOIUrl":"https://doi.org/10.2992/007.084.0402","url":null,"abstract":"ABSTRACT Pipestone Springs Main Pocket (PSMP) (Renova Formation, Jefferson County, Montana) has yielded an unusually rich concentration of mostly small-bodied Chadronian (late Eocene) mammals. Coprolites are common at PSMP and indicate which taxa and skeletal elements were consumed, as well as provide insight as to which carnivore species were likely to have deposited their feces at the site. Two distinct coprolite groupings were recognized based on differences in diameter, morphology, and abundance of bone. The sample of larger coprolites ranges in diameter from 16–29 mm and lacks a distinct mode. Some of the larger coprolites contain bone, but if present, it is sparse, poorly preserved, and unidentifiable. The sample of smaller coprolites varies in diameter from 4–15 mm and has a prominent mode at 10–11 mm. Many of the smaller coprolites contain abundant bone that is often highly fragmented. Osteoderms, bone ends, or dental elements identified to taxon in smaller coprolites indicate that marsupials, lizards, lagomorphs, and rodents were prey of smaller PSMP carnivores. Most elements identified as lagomorph or rodent probably represent Palaeolagus temnodon and Ischyromys veterior based on their high abundance in surface collections. Undigested bone from disaggregated carnivore feces did contribute to the large number of small dentigerous elements recovered from surface collections at PSMP, but it probably was not a major source because only two smaller coprolites had an exposed partial dentary or maxilla. The remains of mammalian carnivores are comparatively rare at PSMP and nine taxa are described, 52% of which represent Hesperocyon gregarius and 21% Brachyrhynchocyon dodgei. If the percentage of surface collected specimens for each carnivore taxon at PSMP is a reflection of activity at the depositional site, most of the smaller coprolites probably represent Hes. gregarius. To test this hypothesis, the ratios between feces diameter and body mass, as well as average lower first molar, (m1), length and body mass in an extant canid were applied to m1s of Hes. gregarius and the smaller coprolites from PSMP. Results indicate a mass of 3.3 kg for the smaller PSMP carnivore and 2.9 kg for Hes. gregarius from PSMP, both similar to the mass of Hesperocyon based on skeletal material. Also, the mode of smaller diameter coprolites is more prominent than the mode of the diameter of feces from an extant canid, which suggests that most of the smaller PSMP coprolites represent the activity of a single species, in this case Hes. gregarius. Many larger coprolites at PSMP probably represent Br. dodgei based on its high relative abundance, but the lack of a prominent mode for the larger coprolites suggests that one or more other species also contributed to the sample.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"9 1","pages":"265 - 285"},"PeriodicalIF":1.1,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85140162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Nine rodents are described from the Whitneyan (middle Oligocene) White Hills fauna of Montana. Of these, three new genera are described: the aplodontid Altasciurus, the cylindrodontid Lophicylindrodon, and the castorid Montanacastor. Prosciurus relictus (Cope, 1873) is named as the type species of Altasciurus. The other genera are unique to this fauna and are based on new species; Lophicylindrodon expiratus and Montanacastor simplicidens. In addition, two more new species are described: the eomyid Orelladjidaumo exiguus and the cricetid Willeumys argosorus. The rodent fauna from White Hills is believed to be Whitneyan in age because of the occurrence of Eumys brachyodus Wood, 1937, and Leptodontomys douglassi (Burke, 1934); both elsewhere known from the Whitneyan. The rodent fauna is unique for several reasons: 1) a much lower diversity of rodents than in comparably aged faunas; 2) the number of unique species (four of nine); 3) the relict occurrence of a cylindrodontid (otherwise latest occurrence in the Chadronian); and 4) the extremely high proportion of a single species (A. relictus makes up over 70% of the number of specimens in the fauna). The uniqueness of this fauna may be explained by the fact that the other well-known Whitneyan faunas are from the Great Plains, whereas the White Hills fauna was likely from an isolated intermountain basin. However, taphonomic factors may have controlled the relative numbers of specimens of each species.
{"title":"A Unique Rodent Fauna from the Whitneyan (Middle Oligocene) of Southwestern Montana","authors":"W. Korth, Alan R. Tabrum","doi":"10.2992/007.084.0401","DOIUrl":"https://doi.org/10.2992/007.084.0401","url":null,"abstract":"ABSTRACT Nine rodents are described from the Whitneyan (middle Oligocene) White Hills fauna of Montana. Of these, three new genera are described: the aplodontid Altasciurus, the cylindrodontid Lophicylindrodon, and the castorid Montanacastor. Prosciurus relictus (Cope, 1873) is named as the type species of Altasciurus. The other genera are unique to this fauna and are based on new species; Lophicylindrodon expiratus and Montanacastor simplicidens. In addition, two more new species are described: the eomyid Orelladjidaumo exiguus and the cricetid Willeumys argosorus. The rodent fauna from White Hills is believed to be Whitneyan in age because of the occurrence of Eumys brachyodus Wood, 1937, and Leptodontomys douglassi (Burke, 1934); both elsewhere known from the Whitneyan. The rodent fauna is unique for several reasons: 1) a much lower diversity of rodents than in comparably aged faunas; 2) the number of unique species (four of nine); 3) the relict occurrence of a cylindrodontid (otherwise latest occurrence in the Chadronian); and 4) the extremely high proportion of a single species (A. relictus makes up over 70% of the number of specimens in the fauna). The uniqueness of this fauna may be explained by the fact that the other well-known Whitneyan faunas are from the Great Plains, whereas the White Hills fauna was likely from an isolated intermountain basin. However, taphonomic factors may have controlled the relative numbers of specimens of each species.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"6 1","pages":"319 - 340"},"PeriodicalIF":1.1,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80903512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Among the collections made during the 1896–1899 Princeton Expeditions to Patagonia are three specimens with partial crania and postcrania of Necrolestes patagonensis Ameghino, 1891, from Santa Cruz Province, Argentina. Necrolestes has anatomical specializations found in extant subterranean mammals, and other features identifying Necrolestes as a late Miocene member of the South American Meridiolestida, a non-therian clade that otherwise is limited to the Cretaceous and Paleocene. Anatomical aspects of the three Princeton specimens have been reported previously but they are more fully described here after additional preparation. The most novel discoveries concern specializations of the snout that help identify Necrolestes as a head-lift digger, as are the extant African golden moles and Australian marsupial moles. As in other meridiolestidans and most non-therian mammals, Necrolestes has a septomaxilla at the external nasal aperture. However, the septomaxilla of Necrolestes has structures that buttress an internarial bar and what we interpret as ossified external nasal cartilages, a remarkable adaptation for digging not known in any extant subterranean therians. The upturned snout of Necrolestes produces a shovel effect and also is known in two lineages of subterranean placentals, namely Oligocene palaeanodonts and Miocene proscalopid soricomorphs. The braincase, ear region, and basicranial vasculature are built on a pattern like that in other non-therian mammals, but additional spaces in the squamosal and exoccipital bones increase the volume of the middle ear, which in extant therians is associated with enhancement of low-frequency hearing, another subterranean adaptation. Our findings reinforce the meridiolestidan affinities for Necrolestes and reconstruction of its subterranean habit.
{"title":"Craniomandibular Anatomy of the Subterranean Meridiolestidan Necrolestes patagonensis Ameghino, 1891 (Mammalia, Cladotheria) from the Early Miocene of Patagonia","authors":"J. Wible, G. Rougier","doi":"10.2992/007.084.0302","DOIUrl":"https://doi.org/10.2992/007.084.0302","url":null,"abstract":"ABSTRACT Among the collections made during the 1896–1899 Princeton Expeditions to Patagonia are three specimens with partial crania and postcrania of Necrolestes patagonensis Ameghino, 1891, from Santa Cruz Province, Argentina. Necrolestes has anatomical specializations found in extant subterranean mammals, and other features identifying Necrolestes as a late Miocene member of the South American Meridiolestida, a non-therian clade that otherwise is limited to the Cretaceous and Paleocene. Anatomical aspects of the three Princeton specimens have been reported previously but they are more fully described here after additional preparation. The most novel discoveries concern specializations of the snout that help identify Necrolestes as a head-lift digger, as are the extant African golden moles and Australian marsupial moles. As in other meridiolestidans and most non-therian mammals, Necrolestes has a septomaxilla at the external nasal aperture. However, the septomaxilla of Necrolestes has structures that buttress an internarial bar and what we interpret as ossified external nasal cartilages, a remarkable adaptation for digging not known in any extant subterranean therians. The upturned snout of Necrolestes produces a shovel effect and also is known in two lineages of subterranean placentals, namely Oligocene palaeanodonts and Miocene proscalopid soricomorphs. The braincase, ear region, and basicranial vasculature are built on a pattern like that in other non-therian mammals, but additional spaces in the squamosal and exoccipital bones increase the volume of the middle ear, which in extant therians is associated with enhancement of low-frequency hearing, another subterranean adaptation. Our findings reinforce the meridiolestidan affinities for Necrolestes and reconstruction of its subterranean habit.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"1 1","pages":"183 - 252"},"PeriodicalIF":1.1,"publicationDate":"2017-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82336491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT We describe five partial middle and posterior dorsal vertebrae from an upper Kimmeridgian exposure of the Upper Jurassic Morrison Formation at the Carnegie Quarry of Dinosaur National Monument (Utah, USA), and refer these vertebrae to the poorly known diplodocid sauropod dinosaur genus Barosaurus Marsh, 1890. The small size and unfused neurocentral junctions of these vertebrae indicate that they belonged to a subadult individual and the osteologically youngest specimen yet described for the genus. We also provide corroborating evidence for the pneumatic hiatus previously hypothesized for Barosaurus and identify a previously unrecognized autapomorphy of the genus, the presence of an anterodorsallyoriented accessory lamina arising from the spinodiapophyseal lamina on dorsal vertebrae. Furthermore, we document a temporal uncoupling of neural spine lamination and pneumatization of the centrum, such that full development of the laminae preceded development of sharp-lipped pleurocoels in dorsal vertebrae.
{"title":"A Juvenile Specimen of Barosaurus Marsh, 1890 (Sauropoda: Diplodocidae) from the Upper Jurassic Morrison Formation of Dinosaur National Monument, Utah, USA","authors":"Gina M. Hanik, M. Lamanna, John A. Whitlock","doi":"10.2992/007.084.0301","DOIUrl":"https://doi.org/10.2992/007.084.0301","url":null,"abstract":"ABSTRACT We describe five partial middle and posterior dorsal vertebrae from an upper Kimmeridgian exposure of the Upper Jurassic Morrison Formation at the Carnegie Quarry of Dinosaur National Monument (Utah, USA), and refer these vertebrae to the poorly known diplodocid sauropod dinosaur genus Barosaurus Marsh, 1890. The small size and unfused neurocentral junctions of these vertebrae indicate that they belonged to a subadult individual and the osteologically youngest specimen yet described for the genus. We also provide corroborating evidence for the pneumatic hiatus previously hypothesized for Barosaurus and identify a previously unrecognized autapomorphy of the genus, the presence of an anterodorsallyoriented accessory lamina arising from the spinodiapophyseal lamina on dorsal vertebrae. Furthermore, we document a temporal uncoupling of neural spine lamination and pneumatization of the centrum, such that full development of the laminae preceded development of sharp-lipped pleurocoels in dorsal vertebrae.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"144 1","pages":"253 - 263"},"PeriodicalIF":1.1,"publicationDate":"2017-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77426193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT A new late Mississippian trilobite species, Kaskia pitkinensis, new species, is described from the Pitkin Formation of Arkansas. Kaskia pitkinensis, recovered from early Serpukhovian strata, is the youngest species of the Kaskia clade known in the United States. Kaskia c.f. K. wilsoni (Walter, 1924) also is illustrated. Cyrtoproetus kerhini, new species, from the upper Fayetteville Formation of Arkansas is also described. Richterella hindesvillensis Hessler, 1965, from the Hindesville Limestone of Oklahoma, is herein reassigned to the genus Cyrtoproetus Reed, 1943. Cyrtoproetus kerhini, new species, and C. hindesvillensis (Hessler, 1965) are the first known occurrences of Cyrtoproetus in North America.
{"title":"Some New Late Mississippian Trilobites from Oklahoma and Arkansas","authors":"D. Brezinski","doi":"10.2992/007.084.0203","DOIUrl":"https://doi.org/10.2992/007.084.0203","url":null,"abstract":"ABSTRACT A new late Mississippian trilobite species, Kaskia pitkinensis, new species, is described from the Pitkin Formation of Arkansas. Kaskia pitkinensis, recovered from early Serpukhovian strata, is the youngest species of the Kaskia clade known in the United States. Kaskia c.f. K. wilsoni (Walter, 1924) also is illustrated. Cyrtoproetus kerhini, new species, from the upper Fayetteville Formation of Arkansas is also described. Richterella hindesvillensis Hessler, 1965, from the Hindesville Limestone of Oklahoma, is herein reassigned to the genus Cyrtoproetus Reed, 1943. Cyrtoproetus kerhini, new species, and C. hindesvillensis (Hessler, 1965) are the first known occurrences of Cyrtoproetus in North America.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"24 1","pages":"173 - 178"},"PeriodicalIF":1.1,"publicationDate":"2017-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85698907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Eoastrapostylops riolorense Soria and Powell, 1981, is a primitive meridiungulate mammal known by two specimens from the early Paleogene Río Loro Formation, in NW Argentina. The holotype and most complete specimen is an almost complete skull, mandible, and a few associated postcranial elements. Eoastrapostylops is one of the oldest South American ungulates with a well-preserved skull; although its original description included some cranial characters, its attribution to the endemic South American Order Astrapotheria and the concomitant phylogenetic consequences were based on dental features. New preparation and examination of the holotype (PVL 4216) revealed features not mentioned and/ or incorrectly interpreted in previous studies; particularly important are those of the auditory region. The cranial anatomy is here re-described and compared with that of Astrapotherium Burmeister, 1879, providing the first detailed description of a basal meridiungulate auditory region. The general structure of the preserved elements of E. riolorense resembles more closely that of archaic “ungulates” (i.e., condylarths) and litopterns than that of Astrapotherium or other astrapotheres with known skulls (e.g., Trigonostylops Ameghino, 1897, Astraponotus Ameghino, 1901); the more remarkable differences are: presence of distinct apertures (foramen ovale) for passage of the mandibular ramus of the trigeminal nerve, surfaces on the alisphenoid and squamosal for attachment of the ectotympanic bone, low and crest-like postglenoid process, postglenoid foramen medial to the postglenoid process and not piercing its base, almond-shaped promontorium with a strong caudal tympanic process almost obliterating the post-promontorial tympanic sinus, and the mastoid process exposed laterally and posteriorly. We performed three sets of cladistic analyses based on previously published matrices, including dental, cranial, and postcranial features scored in a wide sample of South American ungulates and archaic “ungulates.” The results suggest that Eoastrapostylops represents a basal meridiungulate lineage that diverged before the differentiation among astrapotheres, pyrotheres, and notoungulates, and thus it can be classified neither within Astrapotheria nor another clade of ordinal rank. Other groups of still uncertain status (e.g., Notopterna, Indalecidae) also would represent independent basal radiations, which would have characterized the early meridiungulate evolution, although this topic needs a more exhaustive exploration.
Eoastrapostylops riolorense Soria and Powell, 1981，是阿根廷西北部早古近纪Río Loro组的两个标本中已知的一种原始子脉哺乳动物。完整型和最完整的标本是一个几乎完整的头骨、下颌骨和一些相关的颅后器官。Eoastrapostylops是南美洲最古老的有蹄类动物之一，头骨保存完好;虽然其最初的描述包括一些颅部特征，但其归属于特有的南美星颅目及其伴随的系统发育结果是基于牙齿特征的。全新的全型(PVL 4216)制备和检查揭示了以前研究中未提及和/或错误解释的特征;听觉区域尤为重要。颅解剖在这里被重新描述，并与astapotherium Burmeister, 1879进行比较，提供了一个基底经脉听觉区域的第一个详细描述。相较于星甲目或其他已知头骨的星甲目(如Trigonostylops Ameghino, 1897, Astraponotus Ameghino, 1901)，保存下来的E. riolorense元素的总体结构更接近于古代“有蹄类”(即，棘骨类)和石目;更显著的区别是:三叉神经下颌骨分支有明显的开口(卵圆孔)，肋突表面和鳞状面附着于外鼓室骨，盂后突低且呈冠状，盂后孔位于盂后突内侧但未刺穿其基部，杏仁状的盂前突具有强大的尾侧鼓室突，几乎覆盖了盂后鼓室窦，乳突向外侧和后方暴露。我们根据先前发表的矩阵进行了三组进化分析，包括在南美有蹄类动物和古代“有蹄类动物”的广泛样本中得分的牙齿、颅骨和颅后特征。结果表明，黄芪甲是一个在黄芪甲、焦虫甲和无节肢动物分化之前就已经分化的基础子午节肢动物谱系，因此它既不能被归为黄芪甲，也不能被归为另一个序级分支。其他仍不确定地位的类群(如Notopterna, Indalecidae)也可能代表独立的基底辐射，这可能是早期经脉进化的特征，尽管这个主题需要更详尽的探索。
{"title":"Re-Description of the Auditory Region of the Putative Basal Astrapothere (Mammalia) Eoastrapostylops riolorense Soria and Powell, 1981. Systematic and Phylogenetic Considerations","authors":"A. Kramarz, M. Bond, G. Rougier","doi":"10.2992/007.084.0204","DOIUrl":"https://doi.org/10.2992/007.084.0204","url":null,"abstract":"ABSTRACT Eoastrapostylops riolorense Soria and Powell, 1981, is a primitive meridiungulate mammal known by two specimens from the early Paleogene Río Loro Formation, in NW Argentina. The holotype and most complete specimen is an almost complete skull, mandible, and a few associated postcranial elements. Eoastrapostylops is one of the oldest South American ungulates with a well-preserved skull; although its original description included some cranial characters, its attribution to the endemic South American Order Astrapotheria and the concomitant phylogenetic consequences were based on dental features. New preparation and examination of the holotype (PVL 4216) revealed features not mentioned and/ or incorrectly interpreted in previous studies; particularly important are those of the auditory region. The cranial anatomy is here re-described and compared with that of Astrapotherium Burmeister, 1879, providing the first detailed description of a basal meridiungulate auditory region. The general structure of the preserved elements of E. riolorense resembles more closely that of archaic “ungulates” (i.e., condylarths) and litopterns than that of Astrapotherium or other astrapotheres with known skulls (e.g., Trigonostylops Ameghino, 1897, Astraponotus Ameghino, 1901); the more remarkable differences are: presence of distinct apertures (foramen ovale) for passage of the mandibular ramus of the trigeminal nerve, surfaces on the alisphenoid and squamosal for attachment of the ectotympanic bone, low and crest-like postglenoid process, postglenoid foramen medial to the postglenoid process and not piercing its base, almond-shaped promontorium with a strong caudal tympanic process almost obliterating the post-promontorial tympanic sinus, and the mastoid process exposed laterally and posteriorly. We performed three sets of cladistic analyses based on previously published matrices, including dental, cranial, and postcranial features scored in a wide sample of South American ungulates and archaic “ungulates.” The results suggest that Eoastrapostylops represents a basal meridiungulate lineage that diverged before the differentiation among astrapotheres, pyrotheres, and notoungulates, and thus it can be classified neither within Astrapotheria nor another clade of ordinal rank. Other groups of still uncertain status (e.g., Notopterna, Indalecidae) also would represent independent basal radiations, which would have characterized the early meridiungulate evolution, although this topic needs a more exhaustive exploration.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"30 1","pages":"164 - 95"},"PeriodicalIF":1.1,"publicationDate":"2017-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80315427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Trilobites from the Lower Mississippian (late Tournaisian) Redwall Limestone of Arizona are rare. Four identifiable specimens were recovered and studied. These specimens, in conjunction with recorded stratigraphic distributions of lost Redwall trilobites, allows for the assemblage of a range chart. Identifiable trilobite species include: Aprathia sp., Phillipsia peroccidens (Hall and Whitfield, 1877), Cummingella? sp., and Cummingella sp. The Redwall trilobites in this small collection exhibit a much closer taxonomic affinity to the late Tournaisian forms known from Europe than they do to species from strata of similar age in the eastern, central, and southern United States. This suggests that during the late Tournaisian the inferred geographic barrier known as the Transcontinental Arch prominently separated the Redwall depositional location from that of the central and eastern United States. This barrier appears to have contributed to the endemism of trilobites of the eastern United States.
亚利桑那州下密西西比(晚图尔奈世)红墙石灰岩中的三叶虫是罕见的。四个可识别的标本被回收和研究。这些标本，与已消失的红墙三叶虫的地层分布记录相结合，可以组合成一个范围图。可识别的三叶虫种类包括:Aprathia sp.， Phillipsia peroccidens (Hall and Whitfield, 1877)， Cummingella?这个小样本中的红墙三叶虫在分类上与欧洲已知的晚Tournaisian三叶虫表现出更密切的关系，而不是与美国东部、中部和南部相似年龄地层中的物种。这表明，在图尔纳世晚期，被称为横贯大陆拱门的推断地理屏障显著地将红墙沉积位置与美国中部和东部的沉积位置分开。这一屏障似乎促成了美国东部三叶虫的地方性。
{"title":"Trilobites from the Redwall Limestone (Mississippian) of Arizona","authors":"D. Brezinski","doi":"10.2992/007.084.0202","DOIUrl":"https://doi.org/10.2992/007.084.0202","url":null,"abstract":"ABSTRACT Trilobites from the Lower Mississippian (late Tournaisian) Redwall Limestone of Arizona are rare. Four identifiable specimens were recovered and studied. These specimens, in conjunction with recorded stratigraphic distributions of lost Redwall trilobites, allows for the assemblage of a range chart. Identifiable trilobite species include: Aprathia sp., Phillipsia peroccidens (Hall and Whitfield, 1877), Cummingella? sp., and Cummingella sp. The Redwall trilobites in this small collection exhibit a much closer taxonomic affinity to the late Tournaisian forms known from Europe than they do to species from strata of similar age in the eastern, central, and southern United States. This suggests that during the late Tournaisian the inferred geographic barrier known as the Transcontinental Arch prominently separated the Redwall depositional location from that of the central and eastern United States. This barrier appears to have contributed to the endemism of trilobites of the eastern United States.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"22 1","pages":"165 - 171"},"PeriodicalIF":1.1,"publicationDate":"2017-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82630777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The large Miocene beavers (Castoridae) Anchitheriomys Roger, 1898, and Amblycastor Matthew, 1918, have been often considered as synonyms (Flynn and Jacobs 2008). Most recently, they have been distinguished as separate genera based on the morphology of the dentary: Amblycastor restricted to North America and Anchitheriormys limited to Eurasia (Mörs and Hulbert 2010). However, the dentary that was cited as evidence for the separation lacks cheek teeth and its specific identification cannot be verified. In addition, a previously undescribed specimen from the type area of “Amblycastor” fluminis Matthew, 1918, demonstrates that the morphologies used to separate these genera are not consistent with the North American specimens; thus, the two genera are synonymous and the North American species should be referred to Anchitheriomys.
{"title":"Comments on the Distinction Between the Miocene Beavers Anchitheriomys Roger, 1898, and Amblycastor Matthew, 1918 (Rodentia, Castoridae)","authors":"W. Korth","doi":"10.2992/007.084.0201","DOIUrl":"https://doi.org/10.2992/007.084.0201","url":null,"abstract":"ABSTRACT The large Miocene beavers (Castoridae) Anchitheriomys Roger, 1898, and Amblycastor Matthew, 1918, have been often considered as synonyms (Flynn and Jacobs 2008). Most recently, they have been distinguished as separate genera based on the morphology of the dentary: Amblycastor restricted to North America and Anchitheriormys limited to Eurasia (Mörs and Hulbert 2010). However, the dentary that was cited as evidence for the separation lacks cheek teeth and its specific identification cannot be verified. In addition, a previously undescribed specimen from the type area of “Amblycastor” fluminis Matthew, 1918, demonstrates that the morphologies used to separate these genera are not consistent with the North American specimens; thus, the two genera are synonymous and the North American species should be referred to Anchitheriomys.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"30 1","pages":"179 - 181"},"PeriodicalIF":1.1,"publicationDate":"2017-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89584030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The cylindrodontid rodent Pseudocylindrodon Burke, 1935, formerly included seven named species, but is here restricted to the type species P. neglectus Burke, 1935, two additional North. American species (P. citofluminis Storer, 1984, and P. lateriviae Storer, 1988), and the Asian species P. mongolicus Kowalski, 1974. The other three species previously assigned to Pseudocylindrodon are here referred to the new genus Dolocylindrodon: D. medius (Burke, 1938), D. tobeyi (Black, 1970), and D. texanus (Wood, 1974) based on a combination of cranial and dental morphology. Two new species of Dolocylindrodon are named from the Chadronian part of the Climbing. Arrow Formation of southwestern Montana: Dolocylindrodon vukae (type species of the genus) and Dolocylindrodon rahnensis. Additional specimens of D. medius from the early Chadronian McCarty's Mountain fauna of Montana are briefly discussed. The recognition of a new genus and two new species of cylindrodonts increases the known diversity of this family to 14 recognized species included in five genera during the North .American Chadronian, the time of greatest diversity of the family. Dolocylindrodon is viewed as a primitive member of the Cylindrodontinae that attained higher-crowned teeth independent of the more hypsodont Cylindrodon Douglass, 1901.
{"title":"A New Genus of Cylindrodontid Rodent from the Chadronian (Late Eocene) of Southwestern Montana and a Reassessment of the Genus Pseudocylindrodon Burke, 1935","authors":"W. Korth, Alan R. Tabrum","doi":"10.2992/007.084.0101","DOIUrl":"https://doi.org/10.2992/007.084.0101","url":null,"abstract":"ABSTRACT The cylindrodontid rodent Pseudocylindrodon Burke, 1935, formerly included seven named species, but is here restricted to the type species P. neglectus Burke, 1935, two additional North. American species (P. citofluminis Storer, 1984, and P. lateriviae Storer, 1988), and the Asian species P. mongolicus Kowalski, 1974. The other three species previously assigned to Pseudocylindrodon are here referred to the new genus Dolocylindrodon: D. medius (Burke, 1938), D. tobeyi (Black, 1970), and D. texanus (Wood, 1974) based on a combination of cranial and dental morphology. Two new species of Dolocylindrodon are named from the Chadronian part of the Climbing. Arrow Formation of southwestern Montana: Dolocylindrodon vukae (type species of the genus) and Dolocylindrodon rahnensis. Additional specimens of D. medius from the early Chadronian McCarty's Mountain fauna of Montana are briefly discussed. The recognition of a new genus and two new species of cylindrodonts increases the known diversity of this family to 14 recognized species included in five genera during the North .American Chadronian, the time of greatest diversity of the family. Dolocylindrodon is viewed as a primitive member of the Cylindrodontinae that attained higher-crowned teeth independent of the more hypsodont Cylindrodon Douglass, 1901.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"27 1","pages":"75 - 93"},"PeriodicalIF":1.1,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90440138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Population declines of species can be a concern, but before taking action, we need to verify whether apparent declines are real. Land snails are one of the most threatened groups of animals in the world, and anecdotes suggest that the abundance of the land snail Anguispira alternata has declined in Pennsylvania, U.S.A., over the past few decades. Might the apparent decline represent inadequate sampling by recent surveyors or could it represent a real decline? Past search effort is rarely documented, hindering direct comparisons of search effort. We used 547 museum records of A. alternata collected primarily from 1890 to 1960 and 2000 to 2015. Following two lines of reasoning, we conclude that the abundance of A. alternata has actually declined. (1) The smaller proportion of collecting events that found A. alternata after year 2000 suggests an actual decline of A. alternata in modern decades, regardless of the total number of collecting events. (2) The accumulation curve of new county records for all land snail species showed similar slopes in both past and modern decades, indicating comparable search effort in both time periods. The apparent decline of A. alternata was not explained by differential effort with respect to snail size or geographical area searched. The decline appears to have begun about 1960, although relatively little collecting effort from 1960 to 2000 decreases confidence in our ability to infer timing of abundance change in those decades. We speculate about three hypotheses regarding the decline (acid precipitation, climate warming, human mediated disturbance) and conclude that the historical increase in acid precipitation best matches the timing of the snail's decline. Population trends of other snail species and trends of A. alternata in other geographical areas should be studied to further explore these and other hypotheses. Our study highlights the importance of museum collections in understanding the current biodiversity crisis.
{"title":"Decline of the Land Snail Anguispira alternata (Pulmonata: Discidae) in Pennsylvania, U.S.A","authors":"T. Pearce, Chelsea D. Arnold","doi":"10.2992/007.084.0103","DOIUrl":"https://doi.org/10.2992/007.084.0103","url":null,"abstract":"ABSTRACT Population declines of species can be a concern, but before taking action, we need to verify whether apparent declines are real. Land snails are one of the most threatened groups of animals in the world, and anecdotes suggest that the abundance of the land snail Anguispira alternata has declined in Pennsylvania, U.S.A., over the past few decades. Might the apparent decline represent inadequate sampling by recent surveyors or could it represent a real decline? Past search effort is rarely documented, hindering direct comparisons of search effort. We used 547 museum records of A. alternata collected primarily from 1890 to 1960 and 2000 to 2015. Following two lines of reasoning, we conclude that the abundance of A. alternata has actually declined. (1) The smaller proportion of collecting events that found A. alternata after year 2000 suggests an actual decline of A. alternata in modern decades, regardless of the total number of collecting events. (2) The accumulation curve of new county records for all land snail species showed similar slopes in both past and modern decades, indicating comparable search effort in both time periods. The apparent decline of A. alternata was not explained by differential effort with respect to snail size or geographical area searched. The decline appears to have begun about 1960, although relatively little collecting effort from 1960 to 2000 decreases confidence in our ability to infer timing of abundance change in those decades. We speculate about three hypotheses regarding the decline (acid precipitation, climate warming, human mediated disturbance) and conclude that the historical increase in acid precipitation best matches the timing of the snail's decline. Population trends of other snail species and trends of A. alternata in other geographical areas should be studied to further explore these and other hypotheses. Our study highlights the importance of museum collections in understanding the current biodiversity crisis.","PeriodicalId":50771,"journal":{"name":"Annals of Carnegie Museum","volume":"71 1","pages":"21 - 9"},"PeriodicalIF":1.1,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80410773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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