The Medicine Pole HiHs local fauna of the late Eocene (Chadronian) of North Dakota affords an exceptional view of a terrestrial community in central North America prior to the climatic deterioration of the earliest Oligocene. The recovery of hundreds of new squamate specimens—particularly abundant dermal skull bones—gives occasion for a re-evaluation of that portion of the assemblage. This work represents the first attempt to associate significant amounts of cranial material from a large number of closely related species. New material of Polychrus charisticus suggests it lies outside the crown of Polychrus (monkey lizards). One previously known but unnamed species is a crown iguanine (true iguana) related to Dipsosaurus dorsalis (the Desert Iguana). Another lies within crown Corytophaninae (basilisks) on the stem of Laemanctus Corytophanes. New material of Tuberculacerta pearsoni indicates that its proposed relation to Phrynosomatinae (fence lizards, horned lizards, and others) was probably in error, however, a well-supported alternative hypothesis has not emerged. Unusual similarities are reported between Hoplocercinae (spiny-tailed and dwarf iguanas) and Cypressaurus, but more material from the latter taxon is needed for a firm phylogenetic determination The presence of a diploglossine (galliwasp) in the assemblage is confirmed and two additional small anguids are reported: an annielline (the last known central North American record of the California limbless lizard lineage) and a gerrhonotine (alligator lizard). On the basis of the new specimens, the number of independent iguanid lineages is reduced from eight to five. However, the higher-taxonomic diversity of Iguanidae in the late Eocene is strengthened. Eocene lizard faunas in central North America show considerable faunal continuity, consistent with the notion that middle and high latitudes were warmer in the late Eocene than previously thought. Late Eocene faunas are still dominated by lineages with exclusively tropical living representatives but also include several lineages that today remain extratropical.

We introduce a spectacular new specimen of a Late Triassic stem crocodilian identified as Poposaurus gracilis. It is part of a poorly known group, Poposauroidea, that, because of its striking similarities with contemporaneous stem avians (“dinosaurs”), has long puzzled archosaur paleontologists. Observed vertebrate locomotor behaviors, together with exceptional preservation of distinctive anatomical clues in this fossil, enable us to examine locomotor evolution in light of new advances in phylogenetic relationships among Triassic archosaurs. Because this stem crocodilian is unambiguously an archosaur, a diapsid, a tetrapod and a choanate sarcopterygian, we can safely infer major components of its locomotor behavior. These inferences, together with form-function constraints, suggest that P. gracilis was a fleet-footed, obligately erect-postured, striding biped. That behavior seems to have been superimposed on the ancestral archosaur's innovative locomotor repertoire, which includes the capacity to “high walk.” These novelties persist in a recognizable form in archosaurs for at least 245 million years and are widely distributed across Earth's surface in diverse ecological settings. They thus qualify as evolutionary innovations regardless of significant differences in diversification rates among extant diapsid reptiles.

A new species of metapseudid tanaidacean from Bermuda and the British Virgin Islands, Synapseudes erici n. sp., is described and illustrated. Specimens were collected in shallow water (down to 6 m) from rock washings. The new species is distinguished by a combination of characters that include a blunt or weakly bilobed rostrum, grossly asymmetrical chelae in the male with massive larger chela nearly as large as the body, three ventral propodal spines on pereopod 1, and a four-segmented uropod endopod. This species is the first member of the genus to be formally described from the warm waters of the northwestern Atlantic.

The Spinelli prospect, located in Glastonbury, Hartford County, Connecticut, USA, was developed at the beginning of the 20th century on a small pegmatite outcrop, most likely for small-scale feldspar and mica mining. Its significance among many other Connecticut pegmatites was augmented by the pivotal role samarskite from the prospect played in the development of U-Pb dating and by the use of other minerals from the same location in a variety of other radioisotopic dating measurements. Old documents, some never published, reveal that in the early days of radioisotopic dating it was Wilbur Foye of Wesleyan University who made the Spinelli prospect samarskite available to scientists at Harvard University, and from there the US Geological Survey and National Research Councils Committee on the Measurement of Geologic Time. Very little has been published about the detailed mineralogy of the host pegmatite and the chemistry of Spinelli samarskite, and almost nothing about the prospects ownership history. The present paper fills these gaps and includes historical aspects, an updated map, a radiological survey of samarskite distribution in the outcrop, the paragenesis of the Spinelli prospect pegmatite and the geochemistry of its most famous mineral.

We conducted ornithological surveys of Tafelberg mountain, Suriname, in November–December 2005 and August–September 2008 and also surveyed the adjacent lowlands in both forest and savanna habitats around the Kappel Airstrip. We recorded a total of 283 species, including 27 Guianan endemics and 2 tepuian endemics (Heliodoxa xanthogonys and Hylophilus sclateri). Four species were new for Suriname and represented significant range extensions (Chamaeza campanisona, Hemitriccus inornatus, Turdus leucops and Turdus olivater). First specimen vouchers were collected for Dysithamnus leucostictus, Heliodoxa xanthogonys, Hylophilus sclateri, Catharus minimus and Piranga rubra, and first vocal evidence was obtained for the presence of Aeronautes montivagus in Suriname. The Kappel avifauna (266 species) was composed of species that would be expected to occur in the Guianan lowlands, but the presence of Hemitriccus inornatus was unexpected and implies a much wider distribution for this elusive tody-tyrant. The avifauna of the Tafelberg summit was composed of 170 species including 18 montane species, most of which are known disjunctly from the Guianan highlands further west, but one (Dysithamnus leucostictus) is otherwise known only from the coastal mountains of Venezuela and the Andes. The isolated Tafelberg population of the latter may represent an undescribed species.

Despite increasing popularity of the island as an ecotourist destination, the ecology and natural history of many organisms native to the Lesser Antillean island of Curaçao have remained enigmatic. We document multiple new observations of the behavioral ecology of several terrestrial and aquatic vertebrates that inhabit Curaçao. We present the first report of avian predation on the endemic Curaçao whiptail lizard, Cnemidophorus murinus, suggesting these lizards play a potentially important role in this island's food web. We also document the first instance of predation by the introduced tropical house gecko. Hemidactylus mabouia, on the native Antilles gecko, Gonatodes antillensis. Tropical house geckos are thought to be displacing native geckos through a combination of niche displacement and competitive exclusion, and our finding suggests that predation on smaller native lizards may be another factor aiding the success of this introduced gecko on Curaçao. We also present repeated observational evidence that juvenile bluehead wrasses (Thalassoma bifasciatum) seek refuge among the sessile and venomous giant Caribbean sea anemones (Condylactis gigantean).