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Analysis of multipronged spicules (Apoidea, Apidae).
Full text link13 pages : illustrations ; 26 cm. Specimens of Tetragonula sapiens collected by Hobart M. van Deusen on 12 May 1964 during the seventh Archbold Expedition to New Guinea.The small (length less than 6 mm) postdefecating larva of Tetragonula (Tetragonula) sapiens (Cockerell) from the Huon Peninsula, Papua New Guinea is described and illustrated, the first representation of the immature stage for any member of this genus of stingless bees. A reexamination of the recently described larva of Melipona fallax Camargo and Pedro using a new technique reveals valuable insights regarding its integumental microstructures. On the basis of these findings and previously published accounts of larval representatives of five other genera (Melipona, Nogueirapis, Partamona, Plebeia, and Trigonisca), a preliminary description of the mature larva of the tribe Meliponini is presented. Multipronged spicules, recently discovered in meliponines, are investigated
Online Materials for Populations of Calcium-and Aluminum Inclusions and Rare Earth Elements in Ornans-group Carbonaceous Chondrites as Associated with the PhD Dissertation of Ellen J. Crapster-Pregont (Constraining the Chemical Environment and Processes in the Protoplanetary Disk: Perspective from Populations of Calcium-and Aluminum-rich Inclusions in Ornans-group and Metal-rich Chondrules in Renazzo-group Carbonaceous Chondrites)
No full textAll of the files herein are supporting data and information from the dissertation completed by Ellen Crapster-Pregont as part of the requirement for a PhD in geochemistry from Columbia University. This dissertation research was advised by Dr. Denton Ebel and the defense committee consisted of Drs. Terry Plank, Dave Walker, Jon Friedrich, and Ben Bostick. The accompanying files are associated with the portion of the dissertation that addresses refractory inclusions and rare Earth elements in various components in Ornans-group carbonaceous chondrites (chapters 1 through 3 and appendices A through D in the dissertation). The following files represent digital copies of the data used to create the plots, figures, tables, and interpretations found within the dissertation. Data range from electron probe microanalyzer element x-ray intensity maps to LA-ICP-MS concentrations to modal phase maps. Detailed descriptions of the contents of each file can be found in “file_descriptions”. See 'show full item record' for the citation and DOI of a full copy of this dissertation
Distribution & biogeographical patterns of Amazon fishes.
Full text link163 pages : illustrations (chiefly color), color maps ; 26 cm.We provide a general compilation of the diversity and geographical distribution of Amazonian fishes, updated to the end of 2018. Our database includes documented distributions of 4214 species (both Amazonian and from surrounding basins), compiled from published information plus original data from ichthyological collections. Our results show that the Amazon basin comprises the most diverse regional assemblage of freshwater fishes in the world, with 2716 valid species (1696 of which are endemic) representing 529 genera, 60 families, and 18 orders. These data permit a view of the diversity and distribution of Amazonian fishes on a basinwide scale, which in turn allows the identification of congruent biogeographical patterns, here defined as the overlapping distributions of two or more lineages (species or monophyletic groups). We recognize 20 distinct distributional patterns of Amazonian fishes, which are herein individually delimited, named, and diagnosed. Not all these patterns are associated with identifiable geographical barriers, and some may result from ecological constraints. All the major Amazonian subdrainages fit into more than one biogeographical pattern. This fact reveals the complex history of hydrographical basins and shows that modern basin-defined units contribute relatively little as explanatory factors for the present distributions of Amazonian fishes. An understanding of geomorphological processes and associated paleographic landscape changes provides a far better background for interpreting observed patterns. Our results are expected to provide a framework for future studies on the diversification and historical biogeography of the Amazonian aquatic biota
Intraspecific variation in late Cretaceous ammonites.
No full text25 pages : illustrations (some color), color map ; 26 cm.This project assesses intraspecific variation through the ontogeny of the ammonite Scaphites whitfieldi Cobban, 1951, from the Upper Cretaceous of the U.S. Western Interior. Our sample consists of 103 dorsoventral cross sections from nine localities that represent two lithofacies (shale and siltstone). We measured four shell parameters (ww/dm, ww/wh, uw/dm, and WER) to describe the ontogenetic changes in shell morphology. We investigated the variation at three growth stages: immediately after hatching (dm = 1 mm), the neanoconch (dm = 4 mm), and the submature stage (defined as at or near the base of the mature hooklike body chamber). In general, the shell becomes more discoidal through ontogeny with a narrower umbilicus and a more compressed whorl section. The results of the univariate analysis indicate that the variation is statistically significantly higher in the neanoconch than in either the hatchling or submature stage. This pattern is also apparent in the multivariate analysis in which the disparity increases markedly from the hatchling to the neanoconch and then decreases again at the submature stage. These results are consistent with the hypothesis that the neanoconch represents a transition in the life history of the animal to a more demersal mode of life followed by a canalization of morphology toward maturity. However, because the neanic transition occurs over a range of sizes, it is possible that some individuals may have already undergone these changes at dm = 4 mm, whereas others may not have, thus inflating the degree of variation. To resolve this issue in the future, it is critical to examine each ontogenetic trajectory individually to pinpoint the exact size at which the morphological changes occur. We also compared the values of ww/dm, ww/wh, uw/dm, and WER of the three growth stages for the sample from siltstone versus the sample from shale. The comparison reveals that the specimens from siltstone occupy lower regions of the morphospace, implying that these specimens are generally more compressed than those from shale. This difference may be related to selection pressures for improved hydrodynamic efficiency in the higher energy environment represented by siltstone
A review of the Eliurus tanala complex (Rodentia, Muroidea, Nesomyidae), with description of a new species from dry forests of western Madagascar. (Bulletin of the American Museum of Natural History, no. 430)
No full text67 pages : illustrations (some color), maps ; 26 cm.Based on 372 specimens examined, we integrated information from two mitochondrial and four nuclear gene sequences, morphological comparisons and morphometric analyses, as well as distributional patterns and ecological occurrences to revise the Eliurus tanala species group (Nesomyinae), a rodent complex endemic to Madagascar’s forests. These evidentiary sources generally proved concordant, supporting description of a new species, E. tsingimbato, indigenous to western dry deciduous forest, mostly associated with limestone karst (tsingy); the two other members of this species group, E. ellermani and E. tanala, are restricted to eastern montane humid forest. Phylogenetic relationships among the three species were poorly resolved, suggesting that their speciation was both recent and rapid. We encountered one instance of conflict between mitochondrial DNA and all other data sources, which we interpret as incomplete lineage sorting involving a population of the new western species. Attention was focused on molecular and morphometric discrimination of the E. tanala and E. antsingy groups where their species distributions overlap in limestone-associated forests of western and northern Madagascar. Phyletic divisions demonstrated within the E. tanala species group are discussed apropos of current models of speciation identified for Malagasy forest-dwelling organisms
Psittacosaurus amitabha, a new species of ceratopsian dinosaur from the Ondai Sayr locality, central Mongolia. (American Museum novitates, no. 3932)
Full text link36 pages : illustrations (chiefly color), color map ; 26 cm.Psittacosaurus is the most speciose nonavian dinosaur genus, represented by at least 10 (and possibly as many as 19) species uncovered over a wide geographic range. Here, we report a new species of large-bodied Psittacosaurus from the Ondai Sayr locality in central Mongolia, which has hitherto produced only one other Psittacosaurus specimen. This new species is characterized by: (1) an elongate snout, with a gently inclined rostronasal margin, (2) a cranium dorsally convex rather than flat, (3) a subtemporal length less than 40% of total skull length, (4) a maxillary lamina that cups the posterior toothrow, (5) five premaxillary foramina arrayed in an arc, (6) an antorbital fossa as long as it is wide, and (7) a palpebral with a well-developed posterior tonguelike process. Psittacosaurus amitabha is resolved as the most basal member of the genus Psittacosaurus in our phylogenetic analysis. This taxon expands our knowledge of the already-speciose genus Psittacosaurus as well as our understanding of the Ondai Sayr fauna, which is poorly known in comparison to other Mongolian Early Cretaceous localities
Karyotypes of Aspidoscelis velox.
No full text7 pages, 1 unnumbered page : illustrations (some color) ; 26 cm.Aspidoscelis velox is a triploid parthenogenetic species with clonal inheritance. We studied karyotypes of population samples representing diverse localities from much of its range. All specimens were triploids, but six different karyotypes were found with small differences among them, apparently resulting from chromosomal mutations that occurred after the origin of the species. As in other parthenogens, karyotypes and allozymes reveal variant clones in A. velox, but we do not recommend naming any of these genetic lineages as separate species. Specimens from the vicinity of Kanab, Kane County, Utah, have been treated by other herpetologists as a separate but morphologically similar species, Aspidoscelis innotatus, based on the assumption that they represented a diploid species. That assumption, made without any genetic evidence of ploidy, was recently based on evidence of histoincompatibility among certain population samples, but that could have been caused by factors other than ploidy (e.g., mutations at histocompatibility loci). We have examined specimens from Kane County, Utah, and all individuals were triploids similar to other population samples of A. velox from Arizona and New Mexico
New species of Adenomera from Amazonia.
No full text21 pages : illustrations (some color), map ; 26 cm.Leptodactylid frogs are phenotypically diverse, widely distributed across the Neotropics, and are known to harbor high levels of cryptic species diversity. This is especially true in Adenomera, where several candidate species have been recognized in a genetics-based study. Here we describe a new Amazonian species of Adenomera, which corresponds to one of the lineages previously identified as a candidate species ("sp. F"). Adenomera phonotriccus, n. sp., differs from all 18 recognized congeners by its unique advertisement call. Moreover, this species can be distinguished from nearly all congeners (except A. cotuba and A. lutzi) in having antebrachial tubercles on the undersides of its forearms. The distribution of A. phonotriccus seems to be restricted to the Araguaia-Xingu interfluve, in the eastern portion of the Brazilian state of Pará. Additional sampling effort on the right margin of the Araguaia River and along the Xingu River drainage should clarify the distribution of A. phonotriccus and perhaps result in the discovery of additional undescribed species of Adenomera in a region with high biological diversity
Supplemental Material for 'Psittacosaurus amitabha, a new species of ceratopsian dinosaur from the Ondai Sayr locality, central Mongolia. (American Museum novitates, no. 3932)'
No full textSupplemental Material for 'Psittacosaurus amitabha, a new species of ceratopsian dinosaur from the Ondai Sayr locality, central Mongolia. (American Museum novitates, no. 3932)