Showing papers in "American Museum Novitates in 2000"
TL;DR: The mesowear analysis as discussed by the authors is based on the physical properties of ungulate foods as reflected in the relative amounts of attritive and abrasive wear that they cause on the dental enamel of the occlusal surfaces.
Abstract: The analysis of fossil ungulate cheek teeth has long been one of the main sources of information about the terrestrial environments of the Cenozoic, but the methods used to extract this information have been either imprecise or prohibitively laborious. Here we present a method based on relative facet development that is quantitative, robust, and rapid. This method, which we term mesowear analysis, is based on the physical properties of ungulate foods as reflected in the relative amounts of attritive and abrasive wear that they cause on the dental enamel of the occlusal surfaces. Mesowear was recorded by examining the buccal apices of molar tooth cusps. Apices were characterized as sharp, rounded, or blunt, and the valleys between them either high or low. The method has been developed only for selenodont and trilophodont molars, but the principle is readily extendable to other crown types. Mesowear analysis is insensitive to wear stage as long as the very early and very late stages are excluded. Cluster analysis of the mesowear variables produces clusters reflecting four main groups from abrasion-dominated to attrition-dominated: grazers, graze-dominated mixed feeders, browse-dominated mixed feeders, and browsers. Most of the relatively few apparent anomalies are explained by more detailed dietary information. Mesowear analysis provides resolution within the main dietary classes and the clustering is virtually identical with and without the index of hypsodonty. Discriminant analysis using all mesowear variables and hypsodonty
506 citations
TL;DR: The oldest fossil bee, “Trigona” prisca, in Late Cretaceous amber from New Jersey, is redescribed and figured and transferred into a new genus, Cretotrigona, supported as sister to the African genus Dactylurina.
Abstract: The oldest fossil bee, ‘‘ Trigona’’ prisca (Apidae: Meliponini), in Late Cretaceous (Maastrichtian) amber from New Jersey, is redescribed and figured. Differences between T. prisca and extant Trigona are noted and the fossil is transferred into a new genus, Cretotrigona. An exploratory cladistic analysis of the Meliponini is undertaken and Cretotrigona supported as sister to the African genus Dactylurina. Affinities between Cretotrigona and recent genera are discussed as are implications of the presence of this derived stingless bee group at the end of the Mesozoic.
123 citations
TL;DR: The first definitive embryonic remains of sauropods preserved inside their eggs were found in the Anacleto Member of the Rio Colorado Formation in Neuquen Province, Argentina.
Abstract: The stratigraphy and age of a sauropod nesting ground containing the first definitive embryonic remains of sauropods preserved inside their eggs is analyzed. The fossil locality, called Auca Mahuevo, occurs in the Anacleto Member of the Rio Colorado Formation in Neuquen Province, Argentina. The 5 m thick interval of overbank mudstones containing the fossilized eggs and embryos occurs near the middle of a 35 m sequence of thin, fluvial, concretionary sandstones and thicker units of silty sandstone. Flooding of shallow stream channels deposited overbank silt and mud on the eggs, killing the embryos and initiating the process of fossilization. Egg fragments containing patches of fossilized integument were found as float weathering out of the mudstone on local flats. Complete eggs containing embryonic bones and teeth were quarried from a steep ridge where the mudstone was exposed. Twelve paleomagnetic samples collected throughout the lower 30 m of the section establish the presence of a Reverse geoma...
79 citations
TL;DR: The skeletal musculature of 11 talpid genera is described, and 58 myological characters are defined and used in a phylogenetic analysis of the Talpidae as mentioned in this paper.
Abstract: The skeletal musculature of 11 talpid genera is described, and 58 myological characters are defined and used in a phylogenetic analysis of the Talpidae. This analysis included the outgroup taxa Atelerix (Erinaceidae) and Blarina (Soricidae), and it discovered a single most parsimonious tree. Inclusion of Uropsilus in a monophyletic Talpidae needs further evaluation, but there is very strong support for the monophyly of other talpids. Contrary to previous interpretations of talpid relationships, this phylogenetic analysis indicates (1) the fully fossorial moles Parascalops, Scalopus, Scapanus, and Talpa are monophyletic; (2) the Eurasian genus Talpa is sister taxon to the North American genera Scalopus and Scapanus; and (3) the long-tailed mole Scaptonyx is part of a clade with the shrew moles Neurotrichus and Urotrichus. Preliminary biogeographic analysis suggests that the Talpidae originated in the Old World, and that there were separate dispersals from Eurasia to North America by Condylura, Neu...
75 citations
TL;DR: In this article, a reclassification of the north temperate taxa associated with the genus Staphylinus sensu lato, and comments on relevant subtribes of the tribe Saphylinini is presented.
Abstract: This paper presents a reclassification of the north temperate taxa associated with the genus Staphylinus sensu lato, and comments on relevant subtribes of the tribe Staphylinini. The treatment contains the following: (1) a historical introduction to the past and recent classification of these genera; (2) a discussion of the characters used herein, many of them being unconventional and used for the first time, and many of which are illustrated either by SEM photomicrographs or by line drawings; (3) a key to the north temperate subtribes of the tribe Staphylinini; (4) a discussion of the diagnostic characters of each of the five relevant subtribes (Philonthina, Quediina, Anisolinina, Staphylinina, and Xanthopygina); (5) a key to the north temperate generic- and subgeneric-level taxa associated with the genus Staphylinus sensu lato; (6) type species information and a discussion of diagnostic characters for each taxon at the generic and subgeneric level; (7) a discussion of reasons for taxonomic and ...
67 citations
TL;DR: Cross River gorillas have smaller dentitions, smaller palates, smaller cranial vaults, and shorter skulls as mentioned in this paper, and are best regarded as a distinct subspecies of G. g. diehli.
Abstract: This study presents the results of a new set of measurements made on museum specimens of gorilla skeletons from the Cross River headwaters. It provides a review of the taxonomy of Cross River gorillas and describes their distribution and related aspects of their natural history. Considering their distinctiveness and geographic isolation, Cross River gorillas are best regarded as a distinct subspecies, G. g. diehli. Compared to other western gorilla populations, Cross River gorillas have smaller dentitions, smaller palates, smaller cranial vaults, and shorter skulls. Although Cross River gorillas do not seem to differ from other western gorillas in either body size or limb long bone lengths, measurements from a single male suggest that they may have shorter hands and feet and a larger opposability index than other western gorillas. Marked variation in the habitats of Cross River gorillas and insufficient data on behavior frustrate attempts to directly associate morphology with ecology. Many of the...
55 citations
TL;DR: It is inferred that the later subdivision and subsidence of major portions of GAARlandia must have finely vicariated its biota (which included sloths at least as early as the Early Oligocene), consistent with several new lines of evidence concerning the paleontological and paleogeographical history of the Caribbean region.
Abstract: As part of ongoing revisionary work on Antillean Megalonychidae, we document four new sloth species from Quaternary cave localities in Haiti and the Dominican Republic.* The new taxa and their tribal affiliations are as follows: Megalocnus zile (Megalocnini), Acratocnus ye (Acratocnini), and Neocnus dousman and N. toupiti (Cubanocnini). Significantly, each is closely related to species in genera long known from Cuba. This observation is of primary biogeographical importance because the most parsimonious explanation for the presence of parallel arrays of lower-level clades of sloths on opposite sides of the Windward Passage is vicariance, not a series of uncoordinated over-water dispersals. For a brief period in the late Paleogene, eastern Cuba, northern Hispaniola, Puerto Rico, and the Aves Rise formed a large positive structure (GAARlandia) that was evidently briefly continuous with northwestern South America. We infer that the later subdivision and subsidence of major portions of GAARlandia mus...
53 citations
TL;DR: In this paper, osteological features of cynodontine species and other characiforms were examined in order to investigate the monophyly of the Cynodontinae and the relationships among its species.
Abstract: Osteological features of cynodontine species and other characiforms were examined in order to investigate the monophyly of the Cynodontinae and the relationships among its species. A number of derived characters corroborated the hypothesis that the Cynodontinae and its three included genera Cynodon, Rhaphiodon, and Hydrolycus are monophyletic. Hydrolycus armatus is the sister group of H. tatauaia; H. scomberoides is the sister group of the clade formed by the latter two species; and H. wallacei is the sister group of the clade formed by H. armatus, H. tatauaia, and H. scomberoides. Rhaphiodon vulpinus is the sister group to Cynodon, and together they are the sister group to the clade formed by Hydrolycus species. Three Cynodon Agassiz, 1829, species are diagnosed. Cynodon gibbus Agassiz, 1829, occurs in the Rio Amazonas and Rio Orinoco basins, and the Rupununi River, Guyana. Cynodon meionactis Gery et al., 1999, occurs in the upper Maroni River, French Guiana, and C. septenarius, new species, occ...
53 citations
TL;DR: The measurements demonstrate that the OH 8 navicular belongs to a rigid foot with an adducted hallux and a strong commitment to terrestriality, which underscores the fallacies inherent in constructing phylogenies on the basis of single bones and/or fragmentary remains, and of reconstructing locomotor behaviors on the based of localized anatomy.
Abstract: To clarify fossil hominid behavior and phylogeny, and to test the accuracy of basing these studies on single bones, navicular measurements of Olduvai and Hadar hominids, Oreopithecus, and a representative sample of humans and great apes were compared. The measurements chosen for comparison quantify the relative orientation, articular area, and curvature of the navicular facets. The measurements demonstrate that the OH 8 navicular belongs to a rigid foot with an adducted hallux and a strong commitment to terrestriality. The Hadar naviculars belong to a foot which lacked a fixed longitudinal plantar arch and had at least a degree of hallucal opposability comparable to that of mountain gorillas. The Oreopithecus navicular belongs to a mobile foot with a widely divergent hallux committed to arboreal behaviors. Multiple discriminant and canonical variate analyses of navicular measurements emphasize the uniqueness of Oreopithecus and the similarities between OH 8 and humans, and between Hadar and Afric...
49 citations
TL;DR: Characters of the male corroborate the hypothesis that Proplebeia constitutes a distinct branch within the lineage of Neotropical Plebeia (s.s.) and discuss possible phylogenetic affinities among PlebeIA, Prople beia, and Nogueirapis silacea, the latter in amber from Chiapas, México.
Abstract: Seventeen specimens of Meliponini in Dominican Republic amber were studied, including eight workers of Proplebeia dominicana and four males, presumably of this same species. Detailed descriptions of two new species, placed tentatively in Proplebeia, are included. Characters of the male (mainly shape of sterna 5 and 6) corroborate the hypothesis that Proplebeia constitutes a distinct branch within the lineage of Neotropical Plebeia (s.s.). We discuss possible phylogenetic affinities among Plebeia, Proplebeia, and Nogueirapis silacea, the latter in amber from Chiapas, Mexico.
45 citations
TL;DR: A cladistic analysis of the subgenera of the paper wasp genus Polybia Lepeletier, and the other genera that construct phragmocyttarus nests, indicates paraphyly of Polybia in terms of the genus Synoecoides Ducke.
Abstract: A cladistic analysis of the subgenera of the paper wasp genus Polybia Lepeletier (Hymenoptera: Vespidae; Polistinae), and the other genera that construct phragmocyttarus nests, is presented. The results clearly indicate paraphyly of Polybia in terms of the genus Synoecoides Ducke. To remove the paraphyly, Synoecoides is reduced in rank, to a subgenus of Polybia, new synonymy.
Journal Article•
TL;DR: Mesowear analysis successfully resolved a test case using the Serengeti grazing succession and appears to be superior to microwear analysis in two cases where the diet of fossil ungulates has been previously studied by microwave and other conventional methods.
TL;DR: A small collection of late Cenozoic fossil vertebrates recovered from a lahar (mudflow) deposit at Locality 12° North on the southern coast of Grenada is reported, regarded as latest Pliocene or slightly younger.
Abstract: We report on a small collection of late Cenozoic fossil vertebrates recovered from a lahar (mudflow) deposit at Locality 12° North on the southern coast of Grenada.* 40K/40Ar–dated hornblende concentrate from the lahar deposit yielded age estimates of 2.6–3.7 Ma (Late Pliocene). Although these estimates date crystallization of the hornblende and not the lahar event, the latter is unlikely to be substantially younger. The contained fauna is here regarded as latest Pliocene or slightly younger. Dental specimens in the collection are readily referable to Hydrochaeridae (Rodentia, Caviida) and Megalonychidae (Xenarthra, Phyllophaga), groups heretofore unknown on this island. The capybara, Hydrochaeris gaylordi, new species, differs from extant Hydrochaeris hydrochaeris in the conformation of the maxillary second molar. The sloth teeth (two caniniforms, one molariform) notably differ from one another in size, but whether they represent one species or two cannot be decided on this evidence. Because of ...
TL;DR: The Navesink Formation of New Jersey is known to contain ammonites from the late Campanian to early Maastrichtian as mentioned in this paper, and these ammonites are correlated with those of Western Europe, the Gulf Coast, and the Western Interior of the United States.
Abstract: New fossil collections provide additional information about the late Campanian and Maastrichtian ammonites from the Navesink Formation of New Jersey. Late Campanian ammonites include Pseudophyllites indra (Forbes, 1846), Nostoceras (N.) approximans (Conrad, 1855) (of which Nostoceras (N.) stantoni Hyatt, 1894, is a synonym), Nostoceras (N.) hyatti Stephenson, 1941, Nostoceras (N.) pauper (Whitfield, 1892), Didymoceras cf. D. draconis (Stephenson, 1941), Exiteloceras rude n. sp., Hoploscaphites pumilus (Stephenson, 1941), and Jeletzkytes cf. J. nodosus (Owen, 1852). Maastrichtian ammonites from the Navesink Formation include Pachydiscus (P.) neubergicus neubergicus(Hauer, 1858), Kitchinites sp., Nostoceras (N.) alternatum (Tuomey, 1854), Baculites sp., Eubaculites cf. E. labyrinthicus (Morton, 1834), Eubaculites sp.?, Jeletzkytes cf. J. plenus (Meek, 1876), Jeletzkytes criptonodosus Riccardi, 1983, and Discoscaphites gulosus (Morton, 1834). These faunas are correlated with those of Western Europe, the Gulf Coast, and the Western Interior of the United States. The older fauna from the basal phosphatic beds of the Navesink Formation at the classic Atlantic Highlands locality is referred to the Nostoceras (N.) hyatti zone. It is late Campanian in age and equivalent to the Nostoceras (N.) pozaryskii/Belemnella langei zone in Europe and the Baculites jenseni zone in the United States Western Interior. In addition, these beds contain ammonites that range into the early Maastrichtian, as well as Pachydiscus (P.) neubergicus, whose appearance marks the base of the Maastrichtian. Thus, these phosphatic beds represent a condensed sequence that spans the late Campanian to early Maastrichtian. Ammonites also occur at other localities in the Navesink Formation in New Jersey, and correspond to higher levels in the Maastrichtian. The youngest ammonite known from the Navesink Formation, Discoscaphites gulosus, from Sewell, New Jersey, indicates a correlation with the Hoploscaphites nicolletii or Jeletzkytes nebrascensis zone of the Western Interior.
TL;DR: The relationships of Megalopsallus within the Phylini are discussed, indicating an obligate association with halophytes, most in the families Ephedraceae (Ephedrales) and Chenopodiaceae and Solanaceae (Angiospermae).
Abstract: Megalopsallus Knight is revised, with 29 valid species recognized; 8 species are described as new and 13 previously described species are newly treated as junior synonyms. Merinocapsus Knight is treated as a junior synonym of Megalopsallus. The species Europiella albipubscens Knight and Europiella monticola Knight, formerly placed in Megalopsallus are treated as incertae sedis and belonging to Europiella, respectively. Habitus and male genitalic illustrations are provided for all Megalopsallus species; scanning micrographs of the head, scent-gland evaporatory area, vestiture, and pretarsus are included for selected species. A key to males is presented. The majority of Megalopsallus spp. are recorded from dry interior portions of the American West; two species are recorded from the Gulf Coast and East Coast of the United States. Host information is presented for most species, indicating an obligate association with halophytes, most in the families Ephedraceae (Ephedrales) and Chenopodiaceae and So...
TL;DR: The male genitalia and host associations of Oligotylus are shown to be distinctive from those of Lepidargyrus, Plagiognathus, and Psallus.
Abstract: Oligotylus Van Duzee, 1916, is revised to include 16 species from western North America, six of which were previously described and placed in Psallus Fieber. Habitus and male genitalic illustrations are provided for all Oligotylus species; scanning micrographs of the head, scent-gland evaporatory area, vestiture, and pretarsus are included for selected species; a key to the species is presented. Oligotylus is compared with Lepidargyrus Muminov, the latter group being represented in North America by a single introduced species, L. ancorifer (Fieber); it is also compared with Plagiognathus Fieber, which is diverse in North America, and Psallus Fieber, which has no species native to North America except possibly at very high latitudes. Included for L. ancorifer are illustrations of male genitalia, scanning micrographs of selected structures, and locality and host data. The male genitalia and host associations of Oligotylus are shown to be distinctive from those of Lepidargyrus, Plagiognathus, and Ps...
TL;DR: A preliminary generic key to known pupae of cleptoparasitic Apoidea exclusive of the Sphecidae is presented.
Abstract: Pupae of the following cleptoparasitic Apidae are described and compared with pupae of other cleptoparasitic members in that family: Neolarra (Neolarra) californica Michener and N. (Phileremulus) vigilans (Cockerell) (Neolarrini); Holcopasites (Trichopasites) insoletus (Linsley) (Ammobatoidini); Osiris pallidus Smith? (Osirini); Mesoplia (Mesoplia) rufipes (Perty) and M. (Eumelissa) species (Ericrocidini); Isepeolus viperinus (Holmberg) (Isepeolini); and Xeromelecta (Melectomorpha) californica (Cresson) and Thyreus species? (Melectini). Pupae of the Neolarrini and Ammobatoidini have not been described before, nor has the pupa of Mesoplia although the pupa of the related Ericrocis is known. The pupa of Isepeolus was briefly described before but not illustrated. The pupa of Xeromelecta californica was illustrated earlier but not described. A preliminary generic key to known pupae of cleptoparasitic Apoidea exclusive of the Sphecidae is presented.
TL;DR: Canephorula apiformis Friese (Apidae: Eucerini) is a monotypic genus of bees endemic to the arid and semi-arid regions of the Argentinian northwest as mentioned in this paper.
Abstract: Data are presented on the nesting and phenology of Canephorula apiformis Friese (Apidae: Eucerini), a monotypic genus of bees endemic to the arid and semi-arid regions of the Argentinian northwest. Aggregations of nests are found in the ground where the surface is horizontal and frequently exposed to the sun. The brood cells, 5–6 cells per nest, are at an approximate depth of 20 cm. Floral hosts include Prosopis strombulifera (Fabaceae), Atamisquea emarginata (Capparidaceae), Larrea divaricata (Zygophyllaceae), and Tessaria absinthioides (Asteraceae) and are visited mainly between 10:00 and 14:00 hr. Adults and immature stages of Melectoides bellus (Jorgensen) (Apidae: Isepeolini) were found in the nests, the first association for this cleptoparasitic tribe with any host other than the genus Colletes. Canephorula apiformis may have two generations per year while the voltinism of its cleptoparasite is uncertain. The mature larvae of both host and cleptoparasite are described for the first time and...
TL;DR: Cladistic analysis indicates that Chalogaster is the sister-group of the genus Metischnogaster van der Vecht, and a revised key to the genera of Stenogastrinae is presented.
Abstract: Chalogaster spatulata, new genus and species, is described from Viet Nam and northern Thailand. The genus belongs to the subfamily Stenogastrinae, a group of social wasps endemic to the Oriental Region. Cladistic analysis indicates that Chalogaster is the sister-group of the genus Metischnogaster van der Vecht. A revised key to the genera of Stenogastrinae is presented.
TL;DR: The morphology of the external surface of the petrosal and its junction with the basioccipital in Paramys copei is described in this article, which reveals that the auditory region retains many primitive features.
Abstract: The morphology of the external surface of the petrosal and its junction with the basioccipital in Paramys copei is described. Comparison with an outgroup of the Cretaceous Vincelestes and Recent Didelphis and Solenodon reveals that the auditory region retains many primitive features. The Eocene paramyines from North America show only slight differences. Sciuravus is set apart by the lack of a ventral petrosal sinus canal between the petrosal and basioccipital and by the facial nerve and stapedial artery sharing a common foramen in the petrosal. European theridomyids, too, are not as primitive as Paramys but share with it and Sciuravus a ridge on the promontorium that separates the transpromontorial continuation of the internal carotid artery from the origin of the tensor tympani muscle. Twelve characters of the auditory region are analyzed and summarized in a data matrix for use in future studies. Relative primitiveness of the auditory region in all of these Eocene rodents suggests that derived c...
TL;DR: A new genus, Galapagonotus Anderson and Lanteri, is described to accommodate Otiorhynchus cuneiformis Waterhouse from the Galapagos Islands, Ecuador, and three new species from Cocos Island, Costa Rica.
Abstract: A new genus, Galapagonotus Anderson and Lanteri, is described to accommodate Otiorhynchus cuneiformis Waterhouse from the Galapagos Islands, Ecuador. Galapagonotus cuneiformis (Waterhouse) is redescribed and a neotype is designated. Galapagonotus is placed within the tribe Entimini, likely in or near the Eustylus group of genera. The species appears restricted to elevations from 300 to 790 m in native Scalesia, Miconia, and fern-sedge habitats in the archipelago. A second new genus, Coconotus Anderson and Lanteri, also is described to accommodate three new species from Cocos Island, Costa Rica. These species, described herein are C. williamsi Anderson and Lanteri, C. kuscheli Anderson and Lanteri, and C. tuberculatus Anderson and Lanteri. Coconotus is placed within the tribe Entimini, with tentative affinities with the Lachnopus-Exophthalmus group of genera. No details are known of the natural history of any Coconotus species.
TL;DR: In this paper, the authors examined the systematic status of the eight subspecies of Thomomys umbrinus within the Mexican Transvolcanic Belt and found that within-population variation was highly influenced by sexual dimorphism and especially by ontogenetic variation.
Abstract: Difficulties in the subspecific identification of more than 200 specimens of Thomomys umbrinus from the State of Tlaxcala led us to examine the systematic status of the eight subspecies recognized within the Mexican Transvolcanic Belt. We gathered representative samples of those subspecies (≥ 50) during three years of fieldwork. These were analyzed together with samples from other populations not previously assigned to subspecies, as well as voucher specimens from several collections. Thirty-seven variables, obtained from 1145 specimens, were analyzed morphometrically using univariate and multivariate statistics. Within-population variation was highly influenced by sexual dimorphism, and especially by ontogenetic variation; therefore, these two factors should be considered carefully when making systematic and taxonomic decisions. Our analysis of geographic variation determined only two recognizable subspecies of Thomomys umbrinus within the Mexican Transvolcanic Belt: Thomomys umbrinus umbrinus (...
TL;DR: Six genera, including Therini, are redefined monophyletically, and two new monotypic genera are proposed: Costicoma and Fascilunaria, and the combination Thera firmata (Hübner) is proposed.
Abstract: To test the monophyly of the tribe Therini and resolve the relationship between Therini and Cidariini, 49 morphological characters of 38 species of Thera and related genera were analyzed cladistically. Five taxa from the Cidariini were chosen for outgroup comparisons. Monophyly of the Therini was not supported and the Therini newly synonymized with Cidariini. Five genera, Praethera Viidalepp, Thera Stephens, Pennithera Viidalepp, Heterothera Inoue, and Diathera Choi, are redefined monophyletically, and two new monotypic genera are proposed: Costicoma, n. gen. and Fascilunaria, n. gen. The combination Thera firmata (Hubner) is proposed. Relationships among the ingroup taxa are largely resolved: (Fascilunaria(Heterothera(Thera(Diathera, Pennithera)))). Synapomorphies and a diagnosis of each genus are given, and a key to the ingroup genera is provided.
TL;DR: Three new species of trilobites are described from the upper level of the Caño del Oeste Formation (Middle Devonian) of Venezuela, reinforcing faunal similarities previously recognized among Devonian brachiopods and trilOBites of Venezuela and North America.
Abstract: Three new species of trilobites are described from the upper level of the Cano del Oeste Formation (Middle Devonian) of Venezuela. These taxa include a phacopinine, Viaphacops venezuelensis, n. sp., and two asteropyginines, Rhenops odremani, n. sp., and Greenops perijaensis, n. sp. The biogeographic implications of these records are discussed. Viaphacops is somewhat cosmopolitan in its distribution. The presence of Rhenops in Venezuela represents a profound range extension beyond the Rhenish-Bohemia region of the Old World Realm. The Venezuelan occurrence of Greenops represents a southerly range extension within the Eastern Americas Realm, reinforcing faunal similarities previously recognized among Devonian brachiopods and trilobites of Venezuela and North America.