6932 research outputs found
Sort by
Revision of Chactopsis.
No full text121 pages : illustrations (some color), maps ; 26 cmThe Neotropical chactid scorpion genus Chactopsis Kraepelin, 1912, is revised. New diagnoses are presented for all previously described species, most of which have not been revised since their original description. The trichobothrial pattern is reinterpreted and the hemispermatophore described for the first time. Chactopsis is restricted to eight species, two of which are new: Chactopsis chullachaqui, n. sp., from Peru and Chactopsis curupira, n. sp., from Brazil. Chactopsis insignis Kraepelin, 1912, is redescribed and supplementary data on pedipalp trichobothria and hemispermatophore (where known) provided for Chactopsis amazonica Lourenço and Francke, 1986, Chactopsis barajuri González-Sponga, 1982, Chactopsis buhrnheimi Lourenço, 2003, Chactopsis siapaensis González-Sponga, 1991, and Chactopsis sujirima González-Sponga, 1982. Two new genera are created to accommodate the remaining species, formerly assigned to Chactopsis, based on a cladistic analysis of morphological characters. Chactopsoides, n. gen., accommodates Chactopsoides anduzei (González-Sponga, 1982), n. comb. (type species), and Chactopsoides marahuacaensis (González-Sponga, 2004), n. comb., Chactopsoides gonzalezspongai, n. sp., from Venezuela, and Chactopsoides yanomami (Lourenço et al., 2011), n. comb., from Brazil. Chactopsoides anduzei, n. comb., is redescribed and Chactopsis carolinae Botero-Trujillo, 2008, synonymized with it. Supplementary data on pedipalp trichobothria are provided for C. marahuacaensis, n. comb. Megachactops, n. gen., accommodates Megachactops coriaceo (González-Sponga, 1991), n. comb., and Megachactops kuemoi, n. sp. (type species), from Venezuela. Supplementary data on pedipalp trichobothria and hemispermatophore are provided for M. coriaceo, n. comb. A key to identification of the species of Chactopsis, Chactopsoides, n. gen., and Megachactops, n. gen., is provided, their morphology illustrated, and distribution records mapped
New material of Mongolemys elegans Khosatzky and Mlynarski, 1971 (Testudines, Lindholmemydidae), from the late Cretaceous of Mongolia with comments on bone histology and phylogeny. (American Museum novitates, no. 3766)
No full text27 p. : ill. (some col.), maps ; 26 cm.Mongolemys elegans Khosatzky and Mlynarski, 1971, is a freshwater lindholmemydid turtle that is very abundant in late Cretaceous (Maastrichtian) pond deposits from the Gobi Desert of Mongolia. Here, we present new data on the morphology, bone histology, and phylogenetic position of M. elegans based on hatchlings, juveniles, and adults collected by American Museum of Natural History and the Mongolian Academy of Sciences joint field expeditions at the Bugin Tsav locality. Phylogenetic analysis using a morphological dataset supports the placement of M. elegans as a stem testudinoid. Bone histology of M. elegans shows similar patterns of thickness and bone tissue type for the internal and external cortexes as in other freshwater turtles. Microstructural samples of fossil bone from M. elegans show exceptional preservation of osteocyte lacuno-canicular networks, and higher values of osteocyte density at the external cortex in contrast to cancellous bone and the internal cortex
Revision of Oedichirus.
No full text137 p. : ill. (some col.), maps ; 26 cm.The New World species of Oedichirus Erichson, 1839, are revised, redescribed, or newly described, illustrated, and included in keys for identification. The morphology of the ventral pterothoracic sclerites is examined and Matsuda's (1970) interpretation is largely adopted over that of Ferris (1940b). Newly discovered characters of the median gonocoxal plate and associated vulvar plate, including its microstructures, are discussed. Prior to the present paper New World species were known in Brazil and Costa Rica, but are herein newly reported for the Dominican Republic, Mexico, Ecuador, Peru, Bolivia, and Argentina; a specimen intercepted at a port in the United States was said to have come from Nicaragua. Eight species were previously described; 19 new ones are added herein, 12 from Brazil (O. apiculus, O. batillus, O. bicristatus, O. bullaglaber, O. bullahirtus, O. clavolateralis, O. clavulus, O. echinatus, O. exilis, O. glabrihamus, O. lunatus, and O. procerus), two from Mexico (O. isthmus and O. sinuosus), and one each from Argentina (O. misionesiensis), Bolivia (O. dilophus), Ecuador (O. distortus), Peru (O. hamatus), and Dominican Republic (O. dominicanensis). A neotype is designated for O. geniculatus and lectotypes are designated for O. brunneus Wendeler, O. pictipes Bierig, O. ohausi Wendeler, O. optatus Sharp, O. sparsipennis Bernhauer, and O. speculifrons Bernhauer. Some species are included in species groups
Braincase of Alioramus.
Get PDF72 p. : ill. (some col.) ; 26 cm. Second specimen collected by the 2001 joint American Museum-Mongolian Academy of Science expedition to the Gobi Desert. Cf. introd.The late Cretaceous tyrannosaurid Alioramus altai is known from a single specimen whose articulated braincase exhibits a nearly unique combination of preservational quality, subadult stage of growth, and morphological complexity. We use a detailed physical preparation combined with high-resolution computed tomography to provide an expanded description of this braincase that includes details of the neurocranium and its dermal roof, pneumatic recesses and sinuses, cranial endocast, and inner ear cavities. A few notable features include a highly developed rostral tympanic recess marked by three pneumatic fenestrae, a highly pneumatic paroccipital process with both rostral and caudal pneumatic foramina, a prootic fossa housing external foramina for the trigeminal and facial nerves, a well-developed superficial lamina of the prootic, an expanded vestibular cavity, and an osseous labyrinth that is plesiomorphic in appearance. These observations, set within the currently available comparative context, elucidate numerous neuroanatomical transformations within Tyrannosauroidea and clarify where more data and work are needed. We expand the discussion for the 21 characters from the neurocranium utilized in a recent revision of tyrannosauroid phylogeny, including a listing of which tyrannosauroid taxa can be scored for the primitive and derived states of each character
Maximizing Darwinian fitness with a costly brain : the neuroeconomics of human decision-making.
No full text106 minutesPaul Glimcher, a professor of neural science, economics, and psychology at New York University, discusses the neuroeconomics of human decision-making and how Darwinian "fitness" can be maximized with a costly brain. Glimcher presents an overview of our current understanding of the human machine for making decisions and shows how puzzling inconsistencies in human behavior emerge from the trade-offs of costs and benefits imposed by the hardware of the brain.American Museum of Natural History
Basibulbus, a hard-bodied, haplogyne spider genus from Chile (Araneae, Dysderoidea). (American Museum novitates, no. 3775)
No full text20 pages : illustrations, some in color ; 26 cmA new genus, Basibulbus, is established to contain some seldom-collected, hard-bodied, haplogyne spiders from Chile. Because of their small size and the heavily scutate abdomen of males, these animals resemble gamasomorphine goblin spiders (Oonopidae), but differ in having a heavily sclerotized sperm duct within the male palp and a normal sperm opening in the epigastric furrow. Their tarsal organs lack both the longitudinal ridge and the serial dimorphism in raised receptor number that are considered synapomorphic for oonopids, but are elevated (albeit only at their proximal end), and the genus is therefore assigned to the Orsolobidae. Three new species are described: B. malleco (the type species) and B. concepcion from central Chile (regions VIII and IX), and B. granizo from further north (Region V). Only one other hard-bodied orsolobid genus has been described (Duripelta Forster from New Zealand); Basibulbus does not seem to be closely related to that genus, and represents another in the long list of relictual, phylogenetically significant, Chilean spider taxa. One of the possible synapomorphies of dysderoids, an oblique unsclerotized strip on the base of the anterior lateral spinnerets (which has been lost in higher gamasomorphines) has apparently been lost independently within Basibulbus. That character is present in B. granizo but absent in at least B. malleco
Panoan languages and linguistics. (Anthropological papers of the American Museum of Natural History, no. 99)
No full text112 pages : map ; 26 cm.Knowledge of Panoan languages and linguistics has increased significantly over the last several decades. The present paper draws upon this new information to produce a current internal classification of all the extant and extinct languages in the Panoan family based on lexical, phonological, and grammatical comparisons. This classification pays special attention to distinguishing dialects from independent languages and to mismatches that exist between linguistically defined languages and socially defined ethnic groups. An evaluation of previously proposed genetic relations to other language families is followed by a discussion of lexical borrowing and possible areal diffusion of grammatical features from and into neighboring non-Panoan languages and Kechua. The history of Panoan linguistics is chronicled from the first Jesuit and Franciscan vocabularies to the most recent contributions, and priorities for future research are suggested. A typological overview of Panoan phonology, morphology, and syntax is provided along with descriptions of some of the extraordinary linguistic features found in the family. Name taboos, postmortem word taboos, in-law avoidance languages, trade languages, ceremonial languages, and other ethnolinguistic phenomena found in the Panoan family are also discussed
Eutretauranosuchus osteology and palate evolution.
No full text55 pages, 1 unnumbered page : illustrations, map ; 26 cm.The goniopholidid Eutretauranosuchus delfsi is currently known from two skulls from the Late Jurassic Morrison Formation of Colorado. Here we present a detailed osteology for a third Eutretauranosuchus delfsi specimen (AMNH FARB 570), consisting of a skull and fragmentary postcranium from Bone Cabin Quarry, Wyoming (Morrison Formation). Additional preparation, computed tomography (CT), and three-dimensional processing of CT images reveal matrix-covered structures on AMNH FARB 570, provide new information on goniopholidid cranial anatomy, and allow for the first description of an articulated North American goniopholidid braincase. These new data, along with restudy of the palatal anatomy in Eutretauranosuchus, provide valuable insight into the phylogenetic history of goniopholidid crocodyliforms. The skull of AMNH FARB 570 is extremely similar to other specimens of E. delfsi and Amphicotylus spp., especially in details of the architecture of the palate. In these Morrison Formation goniopholidids the secondary palate is incomplete such that the nasopharyngeal passage has no ventral floor. Additionally, there is a complex septum, constructed from the vomers and pterygoid, which extends ventrally near to the plane of the secondary palate. Characters diagnosing Eutretauranosuchus delfsi include: (1) an elongate, platyrostral skull; (2) a prominent depression on the posterolateral surface of the alveolar process of the maxilla; (3) minimal lateral undulation of the maxillary tooth row; (4) broadening of the nasals anterior to the prefrontals; (5) nasals that do not contact external nares; (6) a broad, flat interfenestral bar with raised rims along the supratemporal fenestrae; (7) a nasopharyngeal septum formed from diverging vomeral processes anteriorly and a midline pterygoid process posteriorly (also in Amphicotylus lucasii, AMNH FARB 5782); and (8) a vomeral septal complex that forms an X shape in cross section. Based on a revised phylogenetic analysis of 88 crocodylomorph taxa, a novel phylogenetic hypothesis is proposed in which a clade of Calsoyasuchus + Sunosuchus is sister to a clade of Goniopholis baryglyphaeus + (Goniopholis simus + (Amphicotylus lucasii + Eutretauranosuchus delfsi)). Examination of secondary palate characters in Goniopholididae suggests that this group "experimented" with changes to the bony secondary palate a number of times, resulting in morphologies not seen other mesoeucrocodylian clades
Oonopoides.
No full text38 pages : illustrations (some color) ; 26 cm. Part of the oonopid PBI project. (Acknowledgments)The goblin spider genus Oonopoides Bryant was established for a species from Cuba, Oonopoides maxillaris Bryant, and most of the species that have subsequently been assigned to the genus are from that island. The group is actually circum-Caribbean in distribution, but many of its members have been misplaced in the genus Oonops Templeton; here we treat those representatives of the genus that have been collected in North and Central America. Six specific names are transferred from Oonops to Oonopoides: O. endicus Chickering from Florida and the Bahama Islands, O. secretus Gertsch from Texas and Tamaulipas, O mitchelli Gertsch from Mexico, and O. pallidulus (Chickering), O. tenebus Chickering, and O. anoxus Chickering from Panama. Males of O. zullinii Brignoli from Mexico and females of O. secretus are described for the first time; O. tenebus is placed as the male, and hence a junior synonym, of O. pallidulus. The holotype of Oonops zeteki Chickering from Panama is a juvenile that probably belongs to Costarina Platnick and Dupérré and the name is placed as a nomen dubium. Eight new species are described: O. iviei from Florida and the Bahama Islands, O. catemaco, O. chicanna, and O. kaplanae from Mexico, O. hondo from Honduras, O. cristo and O. upala from Costa Rica, and O. cartago from Costa Rica and Panama
