Browsing by Author "Szalay, Frederick S."
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ItemThe affinities of Apterodon (Mammalia, Deltatheridia, Hyaenodontidae). American Museum novitates ; no. 2293(New York, N.Y. : American Museum of Natural History, 1967) Szalay, Frederick S. ItemAsiatic Mesonychidae (Mammalia, Condylarthra). Bulletin of the AMNH ; v. 132, article 2(New York : [American Museum of Natural History], 1966) Szalay, Frederick S.; Gould, Stephen Jay.; Central Asiatic Expeditions (1921-1930)"The subfamily Mesonychinae is rediagnosed. Two new genera and species are described: Mongolonyx dolichognathus from the 'Irdin Manha' beds and Mongolestes hadrodens from the 'Ulan Gochu' Formation of Inner Mongolia. Harpagolestes was probably represented in Asia. ?Harpagolestes orientalis, new species, is described, and the published literature and most of the known specimens of this probably holarctic genus are re-evaluated. This is not, however, a substitute for a systematic revision of Harpagolestes. 'Mesonyx obtusidens,' reported by Gromova (1952), from the Naran Bulak beds of Mongolia, is a species of Pachyaena. Olsenia, a mesonychid described by Matthew and Granger (1925a) based solely on astragali, is not comparable to most of the known genera because of the scarcity of associations between mesonychid teeth and foot bones. The name 'Olsenia' is suggested to be a nomen dubium. A new subfamily, the Hapalodectinae, is erected and is based on Hapalodectes. 'Hapalodectes auctus,' described by Matthew and Granger (1925b), is not a mesonychid but a didymaconid. A new subfamily, the Andrewsarchinae, is diagnosed and is based on Andrewsarchus. Several unallocated Asiatic mesonychids are described. Studying the feeding mechanism of mesonychids led to a re-examination of the previous ideas of Boule, Matthew, and others, who maintained that the Mesonychidae had a very weak jaw musculature and that therefore these mammals could not fill a carnivore or scavenger niche. On the basis of the present studies, it seems very probable that mesonychids had a powerful mandibular musculature. The variation of the length/width ratio of homologous lower check teeth of various species of mesonychids might serve as an index to feeding habit. A relatively long lower cheek tooth suggests a carnivorous habit, while a relatively transverse, blunt lower tooth may indicate an omnivorous or scavenging habit. The Mesonychoidea, in agreement with the action of Van Valen (1966), are transferred from the Carnivora to the Condylarthra. No sound phylogenetic conclusions can be offered for the evolution within the Mesonychidae. The known diversity of mesonychids in the late Eocene and early Oligocene of Asia, and our ignorance of the Asiatic Paleocene and early and middle Eocene faunas would badly mar any proposed phylogeny. As a heuristic alternative, the arrangement of the known mesonychid genera to form several adaptive levels may partially clarify mesonychid diversity. In this paper the following five adaptive levels are suggested without implying any phyletic relationship between the various levels: carnivore level, advanced carnivore level, omnivore-carnivore level, omnivore level, bone-crushing level. This study of Asiatic mesonychids revealed a previously unsuspected diversity of genera among the Asiatic forms in comparison to European and North American taxa. The presence of at least 10 genera is ascertained from the poorly known Asiatic strata in comparison to the seven known genera of mesonychids from the relatively well-known early Tertiary of North America and Europe. For a summary of the known worldwide temporal and geographic distribution of the Mesonychidae, see tables 10 and 11"--P. 171. ItemBeginning of the age of mammals in Asia : the late Paleocene Gashato fauna, Mongolia. Bulletin of the AMNH ; v. 144, article 4(New York : [American Museum of Natural History], 1971) Szalay, Frederick S.; McKenna, Malcolm C.; Central Asiatic Expeditions (1921-1930)"The earliest Tertiary mammalian fauna known from Asia occurs in southern Mongolia, where it is found in late Paleocene sediments approximately 55 million years old exposed at Gashato and in the Nemegt Basin. Romer (1966) has proposed, but not defined, a 'Gashatan Asiatic Age' for the Gashato fauna and we propose that the term be extended to the occurrence of the same fauna, although to a different faunal facies, in the Nemegt Basin, subsuming Romer's (1966) 'Ulanbulakian Asiatic Age.' We supply a definition of the 'Gashatan Asiatic Age': the joint overlapping time ranges of Palaeostylops, Pseudictops, Prionessus, and Eurymylus. Additional localities in Sinkiang and Kwangtung may also be Gashatan in age. The Gashato fauna is made up of a mixture of endemic genera and a few genera that evidently reached Asia via the Bering route from North America and beyond. There is no special similarity to Paleocene faunas of Europe, but this could be because of a double filtering action. Gashatan mammals have been the notoungulates, but recently Paleocene notoungulates been found in North America and there is no evidence that notoungulates as such originated in Asia. At the beginning of the Eocene (Sparnacian), increased northern dispersal brought about extensive, but still not complete, faunal replacement in eastern Asia. Analysis of geophysical data, as well as the faunal data, suggests that there is strong evidence for a dry-land dispersal route between the North American and European crustal blocks via Greenland and the Barents shelf as late as Sparnacian time in the Eocene, but not thereafter. During Paleocene time, climate and other factors had a filtering effect on dispersal via both the Bering and Greenland-Barents shelf routes, but the former was closer to the rotational pole position in the Paleocene and was a more effective filter. During Sparnacian time, the Bering area still acted as a filter, but the Greenland-Barents shelf route now showed little filter action. Presumably this was the result of a more equable climate. There is no evidence for a Greenland-Iceland-Faeroes dispersal route and some evidence against it. No attempt is made in the present paper to reevaluate, except insofar as they bear on correlation, the Gashatan multituberculates, pseudictopids, eurymylids, Phenacolophus, or pantodonts, but the following taxonomic adjustments are made: 1. Opisthopsalis is synonymized with Sarcodon, and Sarcodon and Hyracolestes are added to the insectivoran family Deltatheridiidae. 2. A new order, Anagalida, is proposed. The Anagalida includes the families Zalambdalestidae, Pseudictopidae, Anagalidae, and Eurymylidae. The Anagalidae are somewhat lagomorph-like and are believed to be related to lagomorphs. 3. Praolestes is referred to the Zalambdalestidae. 4. The Cretaceous genus Zalambdalestes is known from a single species, Z. lechei. The type specimen of Z. lechei is an extremely aged individual with cheek-tooth crowns nearly worn away. P[superscript]1 and P[superscript]2 have dropped out and the alveoli have closed. The type specimen of 'Z. grangeri' is a somewhat younger individual of the same species and the referred specimens in the Polish collections are younger still. New illustrations of American Museum specimens of Zalambdalestes are provided. 5. The Anagalidae are reported from the Paleocene for the first time and a new genus and species, Khashanagale zofiae, is named. A second species of Khashanagale or of a closely related form is present at Gashato, but is not named. 6. A small Dissacus-like mesonychid is present in the Gashato fauna at Gashato. 7. In the classification of uintatheres, utilization of Flerov's subfamily Prodinoceratinae is advocated in preference to Wheeler's subfamily Bathyopsinae"--P. 313. ItemThe European adapid primates Agerina and Pronycticebus. American Museum novitates ; no. 2466(New York, N.Y. : American Museum of Natural History, 1971) Szalay, Frederick S.; Crusafont Pairó, Miguel, 1910-"The entire sample of Agerina roselli Crusafont-Pairo, 1967, from late early Eocene sediments of the Ager Basin, Spain, is described and compared with its nearest relatives, species of Protoadapis, Pelycodus, and Pronycticebus gaudryi. Agerina is not a necrolemurid as suggested by its describer, but is clearly a member of the Adapidae. Two additional genera, described by Crusafont-Pairo in 1967 as omomyids, Arisella and Pivetonia, bear no particular resemblance to that group. The type specimen of Arisella appears to be an adapid, possibly that of Agerina or Protoadapis, whereas the sample described as Pivetonia isabenae may be near Pseudoloris parvulus. Generic distinction from Pseudoloris is not warranted, although Pseudoloris isabenae may be specifically distinct from Pseudoloris parvulus. A reevaluation of the cranium of Pronycticebus gaudryi confirms the view that this taxon is a primitive adapid"--P. . ItemFirst evidence of tooth replacement in the subclass Allotheria (Mammalia). American Museum novitates ; no. 2226(New York, N.Y. : American Museum of Natural History, 1965) Szalay, Frederick S. ItemThe Hapalodectinae and a phylogeny of the Mesonychidae (Mammalia, Condylarthra). American Museum novitates ; no. 2361(New York, N.Y. : American Museum of Natural History, 1969) Szalay, Frederick S. ItemKennatherium shirensis (Mammalia, Palaeoryctoidea), a new didymoconid from the Eocene of Asia. American Museum novitates ; no. 2342(New York, N.Y. : American Museum of Natural History, 1968) Mellett, James Silvan, 1936-; Szalay, Frederick S.; Central Asiatic Expeditions (1921-1930) ItemMixodectidae, Microsyopidae, and the insectivore-primate transition. Bulletin of the AMNH ; v. 140, article 4(New York : [American Museum of Natural History], 1969) Szalay, Frederick S."Contrary to the practice of many earlier workers, the author of the present paper clearly separates the Paleocene Mixodectidae and the Eocene Microsyopidae. The following species and genera of the insectivore mixodectids are considered valid: Mixodectes pungens, Mixodectes malaris, Elpidophorus elegans, Elpidophorus minor, Eudaemonema cuspidata, Dracontolestes aphantus, and Remiculus deutschi. Various Puercan fossils other than Dracontolestes probably have been incorrectly allocated to the family. The cranial and postcranial anatomy of mixodectids is virtually unknown. An undoubted derivation of mixodectids from any of the known Cretaceous or Paleocene families is not possible. Mixodectids may have originated from some unknown Cretaceous palaeoryctids, erinaceoids, or near-erinaceoid group. Leptictid ancestry for the family is not likely, because even the earliest leptictids are shown to be more advanced than mixodectids in certain important features of the molar teeth. Close ties of mixodectids with Adapisoriculus and Recent tupaiids are not improbable. The possibility of a close plagiomenid-mixodectid affinity is re-examined, and some new evidence is described and illustrated. There is no direct or meaningful indirect evidence to confirm a derivation of plagiomenids from the Mixodectidae. Allocation of the Mixodectoidea to the Dermoptera is considered to be unjustified. Thylacaelurus is not a plagiomenid. Its affinities may lie with insectivores close to the dimylid stem. The Eocene Microsyopidae are known from the following species and genera: Microsyops wilsoni, new species, M. alfi, M. angustidens, M. latidens, M. scottianus, M. lundeliusi, M. elegans, M. annectens, M. kratos, and Craseops sylvestris. Microsyopid cranial anatomy is described in detail; the postcranial anatomy is virtually unknown. From the evidence of the dental morphology, the microsyopids may be derivable from the earliest primates. Because it is not known whether Cretaceous and early and middle Paleocene primates had the relatively advanced basicrania of late Paleocene Plesiadapis and Eocene prosimians, the primitive basicranium of Microsyops is not necessarily decisive against the inclusion of microsyopids in the Primates. As opposed to the usual practice of overburdening the Insectivora and using it as a 'wastebasket,' the microsyopids are placed, although with a query, in the Primates. The late Paleocene Navajovius is allocated, with a query, to the Microsyopidae. Navajovius? mckennai, new species, from the Wasatchian Almagre facies of the San José Formation is poorly known. The insectivore-primate transition was probably initiated at the end of the Cretaceous or earlier by behavioral and physiological adaptations. As behavioral modifications (particularly preference for fruits, leaves, and similar foods as opposed to a predominantly insectivorous diet) affected the feeding habits and behavior, selection gradually altered the morphology and function of the feeding mechanism. The primitive therian and eutherian molar shear was gradually de-emphasized by a reduction of the long paracrista and metacrista, a straightening out of the centrocrista, and the acquisition of more bulbous and less acute cusps and conules. As prevallid-postvallum and postvallid-prevallum shear lost relative importance, the trigonid became narrower and less tall, and the talonid gained functional importance. The teeth, with other parts of the feeding mechanism, became more suitable for mastication and other aspects of oral digestion of a predominantly frugivorous-herbaceous diet. The apatemyids and tupaiids are considered to be independently derived families from the Insectivora, not the Primates. The Paleocene picrodontids, extremely specialized frugivores derived from early primates, epitomize (with other prosimians) the nature and direction of selection pressures responsible for the origin of the Primates"--P. 323. ItemNew paromomyid primate from middle Paleocene beds, Kutz Canyon Area, San Juan Basin, New Mexico. American Museum novitates ; no. 2499(New York, N.Y. : American Museum of Natural History, 1972) Wilson, Robert W. (Robert Warren), 1909-; Szalay, Frederick S."A new species of paromomyid primates is described from the middle Paleocene beds of Kutz Canyon Area, San Juan Basin, New Mexico. Palaechthon nacimienti Wilson and Szalay, new species, is similar to P. alticuspis, the generotype, in size and molar morphology, but shows more primitive proportions between the canine and antemolar teeth. A crushed skull of this species shows the primitively dominant facial cranium of early primates"--P. . ItemOrigins of the Apatemyidae (Mammalia, Insectivora). American Museum novitates ; no. 2352(New York, N.Y. : American Museum of Natural History, 1968) Szalay, Frederick S. ItemThe Picrodontidae, a family of early primates. American Museum novitates ; no. 2329(New York, N.Y. : American Museum of Natural History, 1968) Szalay, Frederick S. ItemSystematics of the Omomyidae (Tarsiiformes, Primates) : taxonomy, phylogeny, and adaptations. Bulletin of the AMNH ; v. 156, article 3(New York : American Museum of Natural History, 1976) Szalay, Frederick S."The taxonomy and analyses of the phylogenetic relationships and adaptations of the subfamilies Anaptomorphinae, Omomyinae, and Ekgmowechashalinae of the undoubted tarsiiform family Omomyidae are presented. The exclusively European subfamily Microchoerinae, although best referred to the Omomyidae, is not revised; pertinent information is treated in the study of phylogenetic ties of the family. The Omomyidae, as far as is known, is Holarctic in distribution. The known stratigraphic ranges are: Anaptomorphinae, early to medial Eocene (North America and Europe); Omomyinae, early Eocene to early Oligocene (North America; early Eocene in Asia); Ekgmowechashalinae, late Oligocene (North America); Microchoerinae, medial Eocene to early Oligocene (Europe). Character analysis of the primarily dental, cranial, and postcranial evidence is presented. Several derived character states, particularly the relative size and point of entry of the intrabullar carotid circulation, unequivocally tie the Omomyidae to the Tarsiidae and also to the Platyrrhini and Catarrhini, thus helping to substantiate the monophyletic status of the suborder Haplorhini, as contrasted with the suborder Strepsirhini. The origin of the Omomyidae, the most primitive known family of the Tarsiiformes, was probably from a primitive lemuriform primate that most closely resembled a member of the Eocene Adapidae. The classification presented is a compromise based on morphological diversity and phylogeny, but it is consistent with the inferred phylogeny. Family Omomyidae: Subfamily Anaptomorphinae: Tribe Anaptomorphini; Subtribe Teilhardinina; Teilhardina; Chlororhysis -- Subtribe Anaptomorphina; Anaptomorphus -- Subtribe Tetoniina; Tetonius; Anemorhysis; Absarokius; Mckennamorphus, new genus -- Tribe Trogoleniurini, new; Trogolemur. Subfamily Omomyinae: Tribe Omomyini; Subtribe Omomyina; Omomys; Chumashius -- Subtribe Mytoniina, new rank; Ourayia; Macrotarsius -- Tribe Washakiini, new; Loveina; Shoshonius; Washakius; Dyseolemur; Hemiacodon -- Tribe Uintaniini, new; Uintanius -- Tribe Utahiini, new; Utahia; Stockia -- Tribe Rooneyiini, new; Rooneyia. Subfamily Ekgmowechashalinae, new: Ekgmowechashala. Family and suborder uncertain: Donrussellia, new genus"--P. 163. ItemThe tarsus of the Paleocene lepticid Prodiacodon (Insectivora, Mammalia). American Museum novitates ; no. 2267(New York, N.Y. : American Museum of Natural History, 1966) Szalay, Frederick S. ItemUintasoricinae, a new subfamily of early Tertiary mammals (?Primates). American Museum novitates ; no. 2363(New York, N.Y. : American Museum of Natural History, 1969) Szalay, Frederick S.