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Supplementary material: Chondrules reveal large-scale outward transport of inner Solar System materials in the protoplanetary disk
Full text linkMethods and Petrographic Descriptions of Selected Chondrules. Petrographic data on each of ten Allende and nine Karoonda chondrules includes tomographic imaging (CT) of each chondrule in its entirety; electron microprobe (EMP) x-ray intensity maps of polished sections of chondrule fragments, in major and minor elements for 18 chondrules; and quantitative EMP analyses of olivine, pyroxene, mesostasis, and other phases in each section. Quantitative analyses of many silicate phases have been performed and that data is presented in this supplement. Petrographic calculations using x-ray map data include modal analyses of the silicate portions of five chondrules (cf. Ebel et al., 2008). Measurement of the opaque/silicate volumetric ratio from 3D CT data would be feasible, as would measurement of chondrule diameters and volumes (cf. Ebel and Rivers, 2007). Estimation of the bulk elemental composition of each chondrule would be possible from these data, perhaps as an exercise for the ambitious student. The degree of alteration of each chondrule may be estimated by inspection of BSE images, in which bright (high Z) areas toward rims show post-formation diffusion of Fe into the chondrule. The related paper can be accessed at https://doi.org/10.1073/pnas.2005235117
Reconstructing Howe Quarry
Full text link56 pages : illustrations (chiefly color), maps ; 26 cm.In 1934, Barnum Brown of the American Museum of Natural History in New York (AMNH) led a large-scale dinosaur excavation in northern Wyoming, where he had found bones two years earlier. Initially, Brown expected to excavate two skeletons of sauropod dinosaurs, but soon after opening the quarry, the team realized that the site far exceeded their expectations: in the end, they unearthed approximately 3000 bones within six months and sent approximately 144 crates back to the AMNH. Due to the enormous number of bones, the site became world famous as a dinosaur graveyard, and media from all over the United States and abroad reported on the expedition. Soon after, however, the collection shifted away from a curatorial focus. What followed was a history of neglect: inappropriate storage conditions, water and fire damage, collapsing wooden boxes, and deteriorating plaster jackets. Relocation and further excavation of the quarry by the Sauriermuseum Aathal (Switzerland; SMA) from 1989 to 1991 confirmed earlier finds of skin impressions and resulted in the recognition of a novel diplodocid sauropod: Kaatedocus siberi. Given that the amount of bones found by the AMNH far exceeded those found by the SMA, a new project was started in 2017 to reassess the state and scientific value of the historic collections at AMNH. Although most of the bones are heavily fragmented, preliminary results show that overall preservation is still exceptional. Here, we reconstruct the history of the excavation, as well as past conservation and preparation procedures, and provide a report of current efforts to prepare, conserve, and catalog the material that has remained in storage since the 1930s. These current efforts show that historic collections, even after decades of neglect, can be of great and unexpected value, both for research and scientific outreach
Two new species of burrowing anemones.
Full text link25 pages : illustrations (chiefly color), color map ; 26 cm.Burrowing sea anemones have a simple morphology with an elongate body and a round aboral end that anchors the animal into mud, sand, or gravel, leaving only the tentacle crown exposed. Edwardsiids are easily differentiated from other burrowing sea anemones by their distinctive mesentery arrangement of eight unpaired macrocnemes at midcolumn with microcnemes restricted to the distal column at the base of the tentacles. Though edwardsiids may be frequently collected in biodiversity surveys, oceanographic expeditions, and ecological monitoring projects, their identification is particularly hampered by their small size, the need for histology, the high number of undescribed species, and the few specialists able to identify them. Scolanthus belongs to the subfamily Edwardsiinae, which is characterized by nemathybomes; it is differentiated from other members of the subfamily by having nemathybomes with basitrichs and periderm in the proximal end, at least eight microcnemes, and 16 or more tentacles in adults. The 14 valid species of Scolanthus are distributed worldwide, but only four species have been recorded from waters deeper than 100 m (S. ingolfi, 1461 m; S. nidarosiensis, 125-150 m; S. intermedius, 223 m; S. triangulus, 71-271 m). Here we describe Scolanthus shrimp, sp. nov., and S. celticus, sp. nov., the first two sea anemones recorded from the deep-sea Whittard Canyon off the coast of Ireland. We provide detailed morphological descriptions of the new species, including micro-CT scanning of S. celticus, and differentiate them from other species in the genus. We also generate a phylogeny using five molecular markers (12S, 16S, 18S, 28S, CO3) to establish the phylogenetic position of the new species. Based on our results, we discuss the relationship of Scolanthus to other edwardsiid genera and implications for the morphology and evolution of the group
Cretaceous diversity of the relict genus Alavesia Waters and Arillo (Diptera: Empidoidea: Atelestidae) (American Museum novitates, no. 3961)
No full text40 pages : illustrations (chiefly color) ; 26 cm.Alavesia has been known on the basis of five species in Late Cretaceous amber from Spain and Myanmar and two extant species from Namibia. Very recently, another extant species has been found in southern Brazil. Here we present a surprising diversity of Alavesia flies from the mid-Cretaceous of Myanmar (Late Albian-Early Cenomanian, ca. 99 Ma), including nine new species: A. angusta, sp. nov., A. brevipennae, sp. nov., A. lanceolata, sp. nov., A. latala, sp. nov., A. longicornuta, sp. nov., A. magna, sp. nov., A. pankowskiorum, sp. nov., A. spinosa, sp. nov., and A. zigrasi, sp. nov. The following new synonymy is proposed: Neoalavesia Poinar and Vega, 2020 = Alavesia Waters and Arillo, 1999. Notes are provided on an unusual structure, leg furrows found on femora to varying degrees among species, sometimes on tibiae, as well as notes on swarming behavior. Alavesia has undergone extensive extinction, a finding that further supports the relict nature of this genus and helps to explain the distribution of the other four Recent genera of Atelestidae, found in south and north temperate regions. Relict arthropod taxa preserved in Burmese amber are briefly reviewed, which also are narrowly endemic to temperate regions today
New genus of Late Cretaceous angel shark
Full text link29 pages : illustrations ; 26 cm.Three-dimensional Late Cretaceous elasmobranch endoskeletal elements (including palatoquadrates, ceratohyals, braincase fragments, and a series of anterior vertebrae) are described from the Late Cretaceous University of Alabama Harrell Station Paleontological Site (HSPS), Dallas County, Alabama. The material is referred to the extant elasmobranch Family Squatinidae on the basis of several distinctive morphological features. It also exhibits features not shared by any modern or fossil Squatina species or the extinct Late Jurassic squatinid Pseudorhina. A new genus and species is erected, despite there being some uncertainty regarding potential synonymy with existing nominal species previously founded on isolated fossil teeth (curiously, no squatinid teeth have been documented from the HSPS). A preliminary phylogenetic analysis suggests that the new genus falls on the squatinid stem, phylogenetically closer to Squatina than Pseudorhina. The craniovertebral articulation in the new genus exhibits features considered convergent with modern batomorphs (skates and rays), including absence of contact between the posterior basicranium and first vertebral centrum, and a notochordal canal which fails to reach the parachordal basicranium. Supporting evidence that similarities in the craniovertebral articulation of squatinoids and batomorphs are convergent rather than synapomorphic (as "hypnosqualeans") is presented by an undescribed Early Jurassic batomorph, in which an occipital hemicentrum articulates with the first vertebral centrum as in all modern sharklike (selachimorph) elasmobranchs. The fossil suggests instead that the batomorph synarcual evolved by fusion of the anterior basiventral and basidorsal cartilages prior to the reduction of the anterior centra and loss of the occipital hemicentrum, not afterward as predicted by the hypnosqualean hypothesis
The late middle Miocene Mae Moh Basin of northern Thailand: the richest Neogene assemblage of Carnivora from Southeast Asia and a paleobiogeographic analysis of Miocene Asian carnivorans. (American Museum novitates, no. 3952)
No full text57 pages : illustrations (some color), maps ; 26 cm.The late middle Miocene fossil-bearing lignite zones of the Mae Moh Basin, northern Thailand, have yielded a rich vertebrate fauna, including two species of Carnivora described thus far: the bunodont otter Siamogale thailandica (known from over a 100 specimens) and the large amphicyonid Maemohcyon potisati. Here we describe additional carnivoran material from Mae Moh comprising new remains of Maemohcyon potisati as well as remains of seven new carnivorans belonging to at least four families: a new species of Siamogale (S. bounosa), a new species of another otter (Vishnuonyx maemohensis), one representative of the genus Pseudarctos (a small amphicyonid), a new genus of Asian palm civet, Siamictis, one representative of another civet (cf. Viverra sp.), a new species of mongoose (Leptoplesictis peignei) and a Feliformia indet. This carnivoran assemblage constitutes one of the richest for the middle Miocene of eastern Asia and by far the richest for the Neogene of Southeast Asia. While the presence of new species indicates a certain degree of endemism for the Mae Moh Basin, paleobiogeographic cluster analyses conducted on carnivoran faunas from the middle and late Miocene of Asia indicates that a southern Asian biogeographic province, analogous to the current Oriental Realm, has existed since at least the middle Miocene. These results strengthen the observation that the Himalayan Mountains and Tibetan Plateau constitute significant physical barriers as well as an important climatic barrier (through the strengthening of monsoon systems) preventing north-south mammal dispersals in Asia since at least the middle Miocene
Hand and foot musculature of anura : structure, homology, terminology, and synapomorphies for major clades (Bulletin of the American Museum of Natural History, no. 443)
No full text155 pages : color illustrations ; 26 cm.Although studies of anuran hand and foot musculature began in the first half of the 19th century, all studies to date have been taxonomically or anatomically restricted in scope, and none has considered the diversity of autopodial myology in Anura as a whole. As a model for future comparisons, we thoroughly describe the hand and foot musculature of an arboreal species (the hylid Triprion petasatus), define the layers in which these muscles are arranged, and attribute presumed functions. On the basis of our myological analysis of 155 species representing 46 of the 54 currently recognized families and main clades of anurans, we describe 20 characters related to hand and foot muscles. Optimization of these characters on the most recent and inclusive phylogenetic hypothesis of Anura results in synapomorphies for several major clades (Bombinatoridae, Alytidae, Xenoanura + Acosmanura, Xenoanura, Pipidae, Acosmanura, Anomocoela, Scaphiopodidae, Pelodytidae + Pelobatidae + Megophryidae, Megophryidae, Neobatrachia, Heleophrynidae, Sooglossidae, Laurentobatrachia, Calyptocephalellidae, Myobatrachoidea, and Nobleobatrachia), including new, nonhomoplastic synapomorphies for clades previously supported only by molecular evidence and a few conflicting phenotypic characters (e.g., Acosmanura, Anomocoela, Neobatrachia). Additionally, we (1) address controversies regarding the homology of anuran and caudate muscles in the context of putative synapomorphies for Ascaphidae + Leiopelmatidae and its sister clade Lalagobatrachia; (2) evaluate a recently proposed terminology for anuran hand and foot musculature; (3) discuss the identities of several hand and foot muscles with problematic homologies; (4) establish a unified terminology for anuran hand and foot muscles, including a list of synonyms for all names employed in the literature; and (5) propose hypotheses for the origin of several myological novelties (neomorphs)
Aspidoscelis laredoensis and A. gularis hybridization.
Full text link13 pages : illustrations (some color) ; 26 cm.Karyotypes and allozyme data for 32 genetic loci overwhelmingly support the conclusion that Aspidoscelis laredoensis is a diploid all-female species that had a hybrid origin between A. gularis x A. sexlineatus. Comparisons of allozymes in individuals representing three mother-to-daughter generations raised in the laboratory suggest that they reproduce by parthenogenetic cloning. In addition to two previously described morphotypes (pattern classes A and B) that occur in southern Texas, we report the existence of three all-female clonal lineages based on allozymes. Individuals of at least one of these lineages occasionally hybridize in nature with males of A. gularis, producing viable and healthy triploid offspring that can grow to adulthood, one of which herself produced an offspring in the laboratory and could have represented a new, clonal triploid species. The possibility exists that cloned offspring of triploid hybrids are present in South Texas and/or northern Mexico, awaiting discovery. These would represent a new species that would appear to be very similar to A. laredoensis
Supplemental Online Material for 'Comparison of the Murchison CM2 and Allende CV3 Chondrites'
No full textSupplemental Online Material for 'Comparison of the Murchison CM2 and Allende CV3 Chondrites