We assembled a dataset of 192 carefully selected species—51 extinct and 141 extant—and 976 apomorphies distributed among 610 phenotypic characters to investigate the phylogeny of Squamata (“lizards,” including snakes and amphisbaenians). These data enabled us to infer a tree much like those derived from previous morphological analyses, but with better support for some key clades. There are also several novel elements, some of which pose striking departures from traditional ideas about lizard evolution (e.g., that mosasaurs and polyglyphanodontians are on the scleroglossan stem, rather than parts of the crown, and related to varanoids and teiids, respectively). Long-bodied, limb-reduced, “snake-like” fossorial lizards—most notably dibamids, amphisbaenians and snakes—have been and continue to be the chief source of character conflict in squamate morphological phylogenetics. Carnivorous lizards (especially snakes, mosasaurs and varanoids) have proven a close second. Genetic data, presumably less burdened by the potential for adaptive convergence related to fossoriality, were expected to resolve these conflicts. Although recent gene phylogenies seem to do so, they also differ radically from any phylogeny based on the phenotype, especially for the most ancient crown squamate divergences that occured during the latter half of the Mesozoic. Our study relied on traditionally prepared specimens as well as high-resolution computed tomography scans that afforded unprecendented access to the cranial anatomy of Squamata. This, along with the inclusion of stem fossils, provided an unparalleled sample of the phenotype enabling us to more fully explore the extreme incongruences between molecular and morphological topologies for the squamate tree of life. Despite this extensive new database, we were unable to find morphological support for the major rearrangement of the deep divergences in Squamata proposed by recent molecular studies. Instead, our data strongly support the same fundamental topology suggested by most previous morphological studies—an Iguania-Scleroglossa basal split, a sister-group relationship between Gekkota and Autarchoglossa, and the divergence between Anguimorpha and Scincomorpha—and documents the extreme degree of morphological homoplasy required by those molecular topologies.

Aidamochelia claustracola, gen. et sp. nov., an endocommensal amphipod, is described from two hexactinellid sponges, Aphrocallistes beatrix and Hertwigia falcifera, from deep coral bioherms off Florida's east coast. Aidamochelia claustracola is the third genus and fifth species described from one of the rarest gammaridean amphipod families, the Didymocheliidae. Aidamochelia claustracola is separated from the two other genera, Didymochelia and Apodidymochelia, in having expanded bases on pereopods five through seven and a biramous third uropod. Observations of live specimens of Aidamochelia claustracola in the host sponges show them to occur as male- female pairs and to have eyes consisting of a triangular ommatidial mass that fades on fixation. Scanning electron microscopy and light microscopy studies of siliceous spicules found in the mouthpart field and gut indicate that Aidamochelia claustracola may feed on tissue of its hosts. This species represents only the second record of the family from the Northern Hemisphere and extends the known range of the family to the western Atlantic Ocean.

The taxonomy of papillated leeches of the genus Placobdella has been extremely problematic, confounded by vague descriptions, redescriptions of species using material across a wide geographic range without reference to type material, and a plethora of dubious taxonomic acts over the course of more than a century. Leeches collected between 2008 and 2011 from the West River, New Haven, New Haven County, Connecticut—the type locality of Placobdella ornata (Verrill, 1872)—were determined to be conspecific with P. ornata (Verrill, 1872) on the basis of comparison to the syntype series. The acquisition of these specimens from the type locality facilitated re-description of P. ornata. The striking similarity of P. ornata to P. phalera (Graf, 1899) prompted comparison of the two species. Specimens conforming to the description of P. phalera were collected from Shivericks Pond in Falmouth, Massachusetts, the type locality of P. phalera. Comparison of these specimens to Graf s (1899) original description of P. phalera (particularly figure 116, which was subsequently designated as the lectotype of P. phalera in the absence of type material) revealed the specimens to be conspecific with the concept of P. phalera articulated by Graf ( 1899) and with P. ornata (Verrill, 1872). Thus, P. phalera is considered a junior synonym of P. ornata. Molecular comparison of the specimens collected from the type localities of P. ornata and P. phalera using the highly conserved gene cytochrome c oxidase subunit I revealed similarities in base sequences of greater than 99.5%, substantiating the synonymy of the species.