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Background Postoperative pain after transforaminal lumbar interbody fusion (TLIF) is a barrier to early mobility. Intraoperative local infiltration of anesthetic agents is standard practice to alleviate postoperative pain. Liposomal formulations may prolong the action of these anesthetic agents. The purpose of this study was to investigate the role of liposomal bupivacaine in postoperative pain control in patients undergoing unilateral, single-level TLIF. Methods From a cohort of 74 patients, half received nonliposomal local anesthetic and half received liposomal bupivacaine (LB) (LB group) via local infiltration. Both groups received a standard postoperative analgesia regimen. Demographic information, postoperative pain scores (visual analog scale), analgesic consumption, length of stay, and complications were retrospectively collected. Results The area under the curve of cumulative pain scores was significantly lower in the LB group between 0 and 12 hours (15.0 ± 15.6 vs. 45.6 ± 21.1, P = 0.003) and between 12 and 24 hours (37.6 ± 20.6 vs. 48.4 ± 24.9, P = 0.05) after surgery. Significantly fewer narcotic equivalents were consumed in the LB group between 12 and 24 hours (16.0 ± 13.4 mg vs. 24.1 ± 19.7 mg intravenous morphine equivalents, P = 0.04). Length of stay was significantly shorter in the LB group than in the control group (3.1 ± 0.9 days vs. 4.3 ± 1.3 days, P Conclusions LB may be a useful adjunct during unilateral TLIF for decreasing pain and narcotic consumption in the first 24 hours after surgery and may also decrease overall length of stay.

Right unilateral ultrabrief (RUL-UB) pulse width electroconvulsive therapy (ECT) has attracted much research attention recently due to its smaller effect on memory than is associated with other forms of ECT, such as bitemporal placement or unilateral standard pulse width. However, RUL-UB has demonstrated slower antidepressant efficacy in comparison to the other techniques. One method to enhance the speed of response to RUL-UB ECT is administration of 5 times a week (termed "daily") treatments as opposed to the more standard twice or thrice weekly schedule. In this open label study, we treated 20 depressed patients with daily RUL-UB treatments for up to 2 weeks (ie, 10 treatments) using standardized assessments of depression and retrograde amnesia. Response and remission rates were commensurate with those reported in other recent studies using this technique with twice or thrice weekly treatment frequencies, and there was no clinically significant effect on retrograde memory function. We conclude that daily administration of RUL-UB ECT may shorten the duration of the course of ECT treatments without compromising cognition. A randomized trial comparing this technique to a thrice weekly schedule of RUL-UB treatments is indicated.

Although the development of second language (L2) oral fluency has been widely investigated over the past several decades, there remains a paucity of research examining language instruction specifically aimed at improving this cognitive skill. In this study, the researchers investigate how instructional techniques adapted from drama can positively impact L2 fluency, comprehensibility, and accentedness—three frequently discussed dimensions of L2 speech. Following a pretest–posttest design, the researchers obtained speech samples from 24 adolescent Brazilian EFL learners before and after their participation in a 4-month drama-based English language program. The development of oral skills by this group was compared with that of a parallel group of learners who received 4 months of instruction in a traditional communicative EFL classroom. Thirty untrained Canadian native English speaker raters evaluated randomized recorded L2 speech samples and provided impressionistic scalar judgments of fluency, comprehensibility, and accentedness. Results indicate that drama-based instruction can lead to significantly larger gains in L2 English oral fluency relative to more traditional communicative EFL instruction; comprehensibility scores also appear to be impacted, but with a much smaller effect; accentedness scores do not seem to benefit from one type of instruction over the other. The authors discuss implications for teaching practice.

Antarctic notothenioids represent one of the few strongly supported examples of adaptive radiation in marine fishes. The extent of population connectivity and structure is unknown for many species, thereby limiting our understanding of the factors that underlie speciation dynamics in this radiation. Here, we assess the population structure of the widespread species Cryodraco antarcticus and its sister species Cryodraco atkinsoni, whose taxonomic status is currently debated. Combining both population genetic and phylogenetic approaches to species delimitation, we provide evidence that C. atkinsoni is a distinct species. Our analyses show that C. atkinsoni and C. antarcticus are recently diverged sister lineages, and the two species differ with regard to patterns of population structure. A systematic and accurate account of species diversity is a critical prerequisite for investigations into the complex processes that underlie the history of speciation in the notothenioid adaptive radiation.

The characteristics of blunt traumatic supratentorial cranial bleed (STCB) types have not been directly compared. The National Trauma Data Bank (NTDB) 2014 was queried for adults with an isolated single STCB n = 57,278. Patients were grouped by STCB categories: subdural (SDH), subarachnoid (SAH), epidural (EDH), intraparenchymal (IPH), and intraventricular hemorrhage (IVH). Frequency, demographics, clinical characteristics, procedures, and outcomes were compared among groups. SDH was the most common STCB (53%) and occurred mostly in elderly patients after a fall (78%), 30% underwent craniotomy and their mortality was 7%. SAH occurred in 32% of patients and carried the lowest mortality (3%). SAH were least likely to have a severe brain injury (7%), and had the lowest Injury Severity Score (ISS, median 8) and complication rate (1%), as well as the shortest hospital length of stay (HLOS, 4.6 ± 6.4 days). EDH was uncommon (2%), occurred in younger patients (median 35 years), and had the highest percentage of traffic related injuries (28%). While EDH patients presented with the poorest neurological status (16% Glasgow Coma Scale ≤ 8, ISS median 18) and were operated on more than any other STCB type (51%), their mortality was lower (4%) and they had the highest discharge to home rate (71%). IVH was the least common (2%), but most lethal (9%) STCB type. These patients had the highest HLOS and intensive care unit LOS, and the lowest craniotomy rate (21%). STCB types have different clinical course, and outcomes. Understanding these differences can be useful in managing patients with STB.

The Pfirrmann and modified Pfirrmann grading systems are currently used to classify lumbar disc degeneration. These systems, however, do not incorporate variables that have been associated with lumbar disc degeneration, including Modic changes, a high intensity zone, and a significant reduction in disc height. A system that incorporates these variables that is easy to apply may be useful for research and clinical purposes. A grading system was developed that incorporates disc structure and brightness, presence or absence of Modic changes, presence or absence of a high intensity zone, and reduction in disc height (disc height less than 5mm). MRI of 300 lumbar discs in 60 patients were analyzed twice by two neurosurgeons. Intra and inter-observer reliabilities were assessed by calculating Cohen's κ values. There were 156 grade zero ("normal"), 50 grade one, 57 grade two, 26 grade three, 10 grade four, and one grade five ("worst") discs. Inter-observer reliability was substantial (κ = 0.66 to 0.77) for disc brightness/structure, Modic changes, and disc height. Inter-observer reliability was moderate (κ = 0.41) for high intensity zone. Intra-observer reliability was moderate to excellent (κ = 0.53 to 0.94) in all categories. Agreement on the total grade between reviewers occurred 71% of the time and a difference of one grade occurred in an additional 25% of cases. Lumbar disc degeneration can be graded reliably by this novel system. The advantage of this system is that it incorporates disc brightness/structure, Modic changes, high intensity zone, and a rigid definition of loss of disc height. This system might be useful in research studies evaluating disc degeneration. Further studies are required to demonstrate possible clinical utility in predicting outcomes after spinal treatments such as fusion.

One of the most striking biodiversity patterns is the uneven distribution of marine species richness, with species diversity in the Indo-Australian Archipelago (IAA) exceeding all other areas. However, the IAA formed fairly recently, and marine biodiversity hotspots have shifted across nearly half the globe since the Paleogene. Understanding how lineages have responded to shifting biodiversity hotspots represents a necessary historic perspective on the formation and maintenance of global marine biodiversity. Such evolutionary inferences are often challenged by a lack of fossil evidence that provide insights into historic patterns of abundance and diversity. The greatest diversity of squirrelfishes and soldierfishes (Holocentridae) is in the IAA, yet these fishes also represent some of the most numerous fossil taxa in deposits of the former West Tethyan biodiversity hotspot. We reconstruct the pattern of holocentrid range evolution using time-calibrated phylogenies that include most living species and several fossil lineages, demonstrating the importance of including fossil species as terminal taxa in ancestral area reconstructions. Holocentrids exhibit increased range fragmentation following the West Tethyan hotspot collapse. However, rather than originating within the emerging IAA hotspot, the IAA has acted as a reservoir for holocentrid diversity that originated in adjacent regions over deep evolutionary time scales.

Research on the efficacy of second language (L2) pronunciation instruction has produced mixed results, despite reports of significant improvement in many studies. Possible explanations for divergent outcomes include learner individual differences, goals and foci of instruction, type and duration of instructional input, and assessment procedures. After identifying key concepts, we survey 75 L2 pronunciation studies, particularly their methods and results. Despite a move towards emphasizing speech intelligibility and comprehensibility, most research surveyed promoted native-like pronunciation as the target. Although most studies entailed classroom instruction, many featured Computer Assisted Pronunciation Teaching (CAPT). Segmentals were studied more often than suprasegmentals. The amount of instruction required to effect change was related to researchers’ goals; interventions focusing on a single feature were generally shorter than those addressing more issues. Reading-aloud tasks were the most common form of assessment; very few studies measured spontaneous speech. The attribution of improvement as a result of instruction was compromised in some instances by lack of a control group. We summarize our findings, highlight limitations of current research, and offer suggestions for future directions.

OBJECTIVEUse of surgical site drains following posterior cervical spine surgery is variable, and its impact on outcomes remains controversial. Studies of drain use in the lumbar spine have suggested that drains are not associated with reduction of reoperations for wound infection or hematoma. There is a paucity of studies examining this relationship in the cervical spine, where hematomas and infections can have severe consequences. This study aims to examine the relationship between surgical site drains and reoperation for wound-related complications following posterior cervical spine surgery.METHODSThis study is a multicenter retrospective review of 1799 consecutive patients who underwent posterior cervical decompression with instrumentation at 4 tertiary care centers between 2004 and 2016. Demographic and perioperative data were analyzed for associations with drain placement and return to the operating room.RESULTSOf 1799 patients, 1180 (65.6%) had a drain placed. Multivariate logistic regression analysis identified history of diabetes (OR 1.37, p = 0.03) and total number of levels operated (OR 1.32, p0.001) as independent predictors of drain placement. Rates of reoperation for any surgical site complication were not different between the drain and no-drain groups (4.07% vs 3.88%, p = 0.85). Similarly, rates of reoperation for surgical site infection (1.61% vs 2.58%, p = 0.16) and hematoma (0.68% vs 0.48%, p = 0.62) were not different between the drain and no-drain groups. However, after adjusting for history of diabetes and the number of operative levels, patients with drains had significantly lower odds of returning to the operating room for surgical site infection (OR 0.48, p = 0.04) but not for hematoma (OR 1.22, p = 0.77).CONCLUSIONSThis large study characterizes current practice patterns in the utilization of surgical site drains during posterior cervical decompression and instrumentation. Patients with drains placed did not have lower odds of returning to the operating room for postoperative hematoma. However, the authors' data suggest that patients with drains may be less likely to return to the operating room for surgical site infection, although the absolute number of infections in the entire population was small, limiting the analysis.

Spondylodiscitis is an infection of the intervertebral disc and adjacent vertebrae. With the advent of minimally invasive spinal surgery, less invasive approaches have been considered for the treatment of discitis. To date, however, there have been no reported cases of a minimally invasive lateral retroperitoneal transpsoas approach for the treatment of spondylodiscitis. The authors report a case of medically refractory discitis in a patient with multiple comorbidities who underwent a successful limited debridement via a lateral transpsoas corridor. This case describes a minimally invasive approach used to treat a patient with lumbar discitis/osteomyelitis who was otherwise a suboptimal surgical candidate.

Pediatric kyphotic deformity is an uncommon clinical entity that can occur following posterior spinal operations and has significant complexity in its treatment. Tension myelopathy in a pediatric patient with a thoracic kyphotic deformity has not been reported in the literature. We present a 17-year-old boy with a progressive thoracic kyphosis and tension myelopathy 4 years after he underwent a thoracic laminoplasty at an outside institution for the treatment of a dorsal spinal arachnoid cyst. At our institution, he was treated with a pedicle subtraction osteotomy as well as thoracic Ponte osteotomies for sagittal plane correction to relieve the tension myelopathy. Both clinical and radiographic improvements were observed after surgery. We review the literature on pediatric thoracic kyphosis and tension myelopathy and the treatment of these pathologies.

Background Third ventricular ependymomas in adults are rare lesions for which the optimal management strategy has not been determined. Objectives We describe our results using a strategy of endoscopic biopsy followed by gamma knife radiosurgery in two patients with low-grade (World Health Organization [WHO] grade II) third ventricular ependymomas. Methods A retrospective analysis of clinical notes, operative records, and neuroimaging was performed for the two patients in this study. The patients both presented with obstructive hydrocephalus and had endoscopic third ventriculostomy performed along with endoscopic tumor biopsy. In both patients the pathology revealed papillary ependymoma WHO grade II. In one patient the endoscopic third ventriculostomy failed, and ventriculoperitoneal shunt placement was necessary. Postoperatively, gamma knife radiosurgery was performed at 1 and 4 months, respectively. Results Both patients in the study experienced symptom resolution following treatment of the hydrocephalus. They returned to their preoperative level of social and occupational function. There was tumor enlargement in one patient in the interval between the initial surgery and the gamma knife treatment. However, neither tumor has enlarged since gamma knife treatment with follow-up of 35 and 41 months, respectively. Conclusions The strategy of endoscopic biopsy followed by gamma knife radiosurgery for adult WHO grade II third ventricular ependymomas has produced acceptable clinical results 3 years posttreatment. Stereotactic radiosurgery without prior microsurgical resection has not previously been reported in these tumors. Longer follow-up is required to evaluate the durability of this treatment.

Object A primary goal in the treatment of patients with warfarin-associated subdural hematoma (SDH) is reversal of coagulopathy with fresh-frozen plasma. Achieving the traditional target international normalized ratio (INR) of 1.3 is often difficult and may expose patients to risks of volume overload and of thromboembolic complications. This retrospective study evaluates the risk of mild elevations of INR from 1.31 to 1.69 at 24 hours after admission in patients presenting with warfarin-associated SDH. Methods Sixty-nine patients with warfarin-associated SDH and 197 patients with non–warfarin-associated SDH treated at a single institution between January 2005 and January 2012 were retrospectively identified. Charts were reviewed for patient age, history of trauma, associated injuries, neurological status at presentation, size and chronicity of SDH, associated midline shift, INR at admission and at hospital Day 1 (HD1), concomitant aspirin or Plavix use, platelet count, and medical comorbidities. Patients were stratified according to use of warfarin and by INR at HD1 (INR 0.8–1.3, 1.31–1.69, 1.7–1.99, and ≥ 2). The groups were evaluated for differences the in rate of radiographic expansion of SDH and in the rate of clinically significant SDH expansion resulting in death, unplanned procedure, and/or readmission. Results There was no difference in the rate of radiographic versus clinically significant expansion of SDH between patients not on warfarin and those on warfarin (no warfarin: 22.3% vs 20.3%, p = 0.866; warfarin: 10.7% vs 11.6%, p = 0.825), but the rate of medical complications was significantly higher in the warfarin subgroup (13.3% for patients who did not receive warfarin vs 26.1% for those who did; p = 0.023). For warfarin-associated SDH, there was no difference in the rate of radiographic versus clinically significant expansion between patients reversed to HD1 INRs of 0.8–1.3 and 1.31–1.69 (HD1 INR 0.8–1.3: 22.5% vs 20%, p = 1; HD1 INR 1.31–1.69: 15% vs 10%, p = 0.71). Conclusions Mild INR elevations of 1.31–1.69 in warfarin-associated SDH are not associated with a markedly increased risk of radiographic or clinically significant expansion of SDH. Larger prospective studies are needed to determine if subtherapeutic INR elevations at HD1 are associated with smaller increases in risk of SDH expansion.

Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the “bush at the top” of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.

Object Although MRI with short-term T1 inversion recovery (STIR) sequencing has been widely adopted in the clearance of cervical spine in adults who have sustained trauma, its applicability for cervical spine clearance in pediatric trauma patients remains unclear. The authors sought to review a Level 1 trauma center's experience using MRI for posttraumatic evaluation of the cervical spine in pediatric patients. Methods A pediatric trauma database was retrospectively queried for patients who received an injury warranting radiographic imaging of the cervical spine and had a STIR-MRI sequence of the cervical spine performed within 48 hours of injury between 2002 and 2011. Demographic, radiographic, and outcome data were retrospectively collected through medical records. Results Seventy-three cases were included in the analysis. The mean duration of follow-up was 10 months (range 4 days–7 years). The mean age of the patients at the time of trauma evaluation was 8.3 ± 5.8 years, and 65% were male. The majority of patients were involved in a motor vehicle accident. In 70 cases, the results of MRI studies were negative, and the patients were cleared prior to discharge with no clinical suggestion of instability on follow-up. In 3 cases, the MRI studies had abnormal findings; 2 of these 3 patients were cleared with dynamic radiographs during the same admission. Only 1 patient had an unstable injury and required surgical stabilization. The sensitivity of STIR MRI to detect cervical instability was 100% with a specificity of 97%. The positive predictive value was 33% and the negative predictive value was 100%. Conclusions Although interpretation of our results are diminished by limitations of the study, in our series, STIR MRI in routine screening for pediatric cervical trauma had a high sensitivity and slightly lower specificity, but may have utility in future practices and should be considered for implementation into protocols.

This mixed-methods study examines the effects of rating scale length and rater experience on listeners' judgments of second-language (L2) speech. Twenty experienced and 20 novice raters, who were randomly assigned to 5-point or 9-point rating scale conditions, judged speech samples of 38 newcomers to Canada on numerical rating scales for comprehensibility, accentedness, and fluency. Results yielded high Cronbach's alpha coefficients and no group differences for rating scale length or rater experience. However, Rasch category probability plots revealed that raters had difficulty differentiating between scale steps, particularly in mid-scale range—a challenge that was exacerbated in the 9-point scale condition. Evidence from verbal protocols and posttask interviews suggested that experienced and novice raters adopted strategies to either draw on or offset their perceived experience with L2 speech in conducting their ratings. Implications for L2 pronunciation research are discussed, including the need to dra...

Treprostinil is a synthetic analog of prostacyclin, which is used for treatment of pulmonary arterial hypertension (PAH). Continuous subcutaneous administration of treprostinil has been proven in randomized controlled trials to improve quality of life, hemodynamics, and 5-year survival in patients with PAH. The efficacy of treprostinil has been attributed to its vasodilatory and antiplatelet effects. Unfortunately, the efficacy of treprostinil in the treatment of PAH is rapidly reversed upon cessation of the continuous infusion. Furthermore, cases of patients rapidly declining or succumbing to disease progression upon cessation of treprostinil have raised significant concern regarding discontinuation of this medication. To date, there are no reports of emergency craniotomies performed in the setting of continuous subcutaneous infusion of treprostinil. The authors report a case of a patient with PAH, treated with continuous administration of subcutaneous treprostinil as well as warfarin, who developed an acute subdural hematoma (SDH). Despite adequate INR (international normalized ratio) correction, the patient eventually underwent an emergency craniotomy for evacuation of the SDH while on continuous treprostinil administration. This case highlights the neurosurgical dilemma regarding the appropriate management of acute SDHs in patients receiving continuous treprostinil infusion.

Object The traditional methods for managing symptomatic chronic subdural hematoma (SDH) include evacuation via a bur hole or craniotomy, both with or without drain placement. Because chronic SDH frequently occurs in elderly patients with multiple comorbidities, the bedside approach afforded by the subdural evacuating port system (SEPS) is an attractive alternative method that is performed under local anesthesia and conscious sedation. The goal of this study was to evaluate the radiographic and clinical outcomes of SEPS as compared with traditional methods. Methods A prospectively maintained database of 23 chronic SDHs treated by bur hole or craniotomy and of 23 chronic SDHs treated by SEPS drainage at Tufts Medical Center was compiled, and a retrospective chart review was performed. Information regarding demographics, comorbidities, presenting symptoms, and outcome was collected. The volume of SDH before and after treatment was semiautomatically measured using imaging software. Results There was no significant difference in initial SDH volume (94.5 cm3 vs 112.6 cm3, respectively; p = 0.25) or final SDH volume (31.9 cm3 vs 28.2 cm3, respectively; p = 0.65) between SEPS drainage and traditional methods. In addition, there was no difference in mortality (4.3% vs 9.1%, respectively; p = 0.61), length of stay (11 days vs 9.1 days, respectively; p = 0.48), or stability of subdural evacuation (94.1% vs 83.3%, respectively; p = 0.60) for the SEPS and traditional groups at an average follow-up of 12 and 15 weeks, respectively. Only 2 of 23 SDHs treated by SEPS required further treatment by bur hole or craniotomy due to inadequate evacuation of subdural blood. Conclusions The SEPS is a safe and effective alternative to traditional methods of evacuation of chronic SDHs and should be considered in patients presenting with a symptomatic chronic SDH.

Natural history collections contain historical records that present snapshots of organisms and communities, and are now more important than ever in the face of rapidly changing environments. The world's largest collection of fishes from The Bahamas is housed at The Academy of Natural Sciences, Philadelphia. These vast Bahamas holdings primarily resulted from the collecting efforts of James Bohlke and Charles Chaplin in the 1950s–1970s. One of the many ways these historical records have been used since their collection is as baseline data for coral reef sites that were revisited decades later to answer questions about changes in coral reef fish community structure through time. Analyses of data collected from resurveys conducted in 2006 and 2010 provided evidence for a relative increase in the abundance of individuals belonging to different trophic groups and families; particularly, a relative increase in herbivores (mainly parrotfishes) and a relative decrease in planktivores. Furthermore, an interesting inverse trend was detected between two nocturnal groups of fishes, where the larger-bodied sqnirrelfishes increased while the smaller-bodied cardinalfishes decreased in relative abundance. These significant differences across trophic groups and families are consistent with the effects of a degraded reef habitat characterized by increased algal cover and fewer shelter spaces. Overall, these resurvey results suggest that neither the coral nor reef-fish communities reflect ‘baseline’ conditions. Continued monitoring of these assemblages using comparative data from multiple replicate samples across time periods will be needed to detect their further change or stabilization.

Fil: O'Dea, Aaron. Smithsonian Tropical Research Institute; Panamá Fil: Lessios, Harilaos A.. Smithsonian Tropical Research Institute; Panamá Fil: Coates, Anthony G.. Smithsonian Tropical Research Institute; Panamá Fil: Eytan, Ron I.. Texas A&M University; Estados Unidos Fil: Restrepo-Moreno, Sergio A.. University of Florida; Estados Unidos. Universidad Nacional de Colombia; Colombia Fil: Cione, Alberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Collins, Laurel S.. Florida International University; Estados Unidos. Smithsonian Tropical Research Institute; Panamá Fil: De Queiroz, Alan. University of Nevada; Argentina Fil: Farris, David W.. Florida State University; Estados Unidos Fil: Norris, Richard D.. Scripps Institution Of Oceanography; Estados Unidos Fil: Stallard, Robert F.. United States Geological Survey; Estados Unidos. Smithsonian Tropical Research Institute; Panamá Fil: Woodburne, Michael O.. University of California; Estados Unidos Fil: Aguilera, Orangel. Universidade Federal Fluminense; Brasil Fil: Aubry, Marie-Pierre. State University of New Jersey; Estados Unidos Fil: Berggren, William A.. State University of New Jersey; Estados Unidos Fil: Budd, Ann F.. University of Iowa; Estados Unidos Fil: Cozzuol, Mario A.. Universidade Federal de Minas Gerais; Brasil Fil: Coppard, Simon E.. Hamilton College; Estados Unidos Fil: Duque Caro, Herman. Academia Colombiana de Ciencias Exactas; Colombia Fil: Finnegan, Seth. University of California at Berkeley; Estados Unidos Fil: Gasparini, Germán Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Grossman, Ethan L.. Texas A&M University; Estados Unidos Fil: Johnson, Kenneth G.. Natural History Museum; Reino Unido Fil: Keigwin, Lloyd D.. Woods Hole Oceanographic Institution; Estados Unidos Fil: Knowlton, Nancy. National Museum of Natural History; Estados Unidos Fil: Leigh, Egbert G.. Smithsonian Tropical Research Institute; Panamá Fil: Leonard Pingel, Jill S.. Washington And Lee University; Estados Unidos Fil: Marko, Peter B.. University of Hawaii at Manoa; Estados Unidos Fil: Pyenson, Nicholas D.. National Museum of Natural History; Estados Unidos Fil: Rachello Dolmen, Paola G.. Smithsonian Tropical Research Institute; Panamá. Texas A&M University; Estados Unidos Fil: Soibelzon, Leopoldo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Soibelzon, Leopoldo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Todd, Jonathan A.. Natural History Museum; Reino Unido Fil: Vermeij, Geerat J.. University of California at Davis; Estados Unidos Fil: Jackson, Jeremy B. C.. National Museum of Natural History; Estados Unidos. Smithsonian Tropical Research Institute; Panamá

BackgroundFlatfish cranial asymmetry represents one of the most remarkable morphological innovations among vertebrates, and has fueled vigorous debate on the manner and rate at which strikingly divergent phenotypes evolve. A surprising result of many recent molecular phylogenetic studies is the lack of support for flatfish monophyly, where increasingly larger DNA datasets of up to 23 loci have either yielded a weakly supported flatfish clade or indicated the group is polyphyletic. Lack of resolution for flatfish relationships has been attributed to analytical limitations for dealing with processes such as nucleotide non-stationarity and incomplete lineage sorting (ILS). We tackle this phylogenetic problem using a sequence dataset comprising more than 1,000 ultraconserved DNA element (UCE) loci covering 45 carangimorphs, the broader clade containing flatfishes and several other specialized lineages such as remoras, billfishes, and archerfishes.ResultsWe present a phylogeny based on UCE loci that unequivocally supports flatfish monophyly and a single origin of asymmetry. We document similar levels of discordance among UCE loci as in previous, smaller molecular datasets. However, relationships among flatfishes and carangimorphs recovered from multilocus concatenated and species tree analyses of our data are robust to the analytical framework applied and size of data matrix used. By integrating the UCE data with a rich fossil record, we find that the most distinctive carangimorph bodyplans arose rapidly during the Paleogene (66.0-23.03Ma). Flatfish asymmetry, for example, likely evolved over an interval of no more than 2.97 million years.ConclusionsThe longstanding uncertainty in phylogenetic hypotheses for flatfishes and their carangimorph relatives highlights the limitations of smaller molecular datasets when applied to successive, rapid divergences. Here, we recovered significant support for flatfish monophyly and relationships among carangimorphs through analysis of over 1,000 UCE loci. The resulting time-calibrated phylogeny points to phenotypic divergence early within carangimorph history that broadly matches with the predictions of adaptive models of lineage diversification.

The formation of the Isthmus of Panama stands as one of the greatest natural events of the Cenozoic, driving profound biotic transformations on land and in the oceans. Some recent studies suggest that the Isthmus formed manymillions of years earlier than the widely recognized age of approximately 3 million years ago (Ma), a result that if true would revolutionize our understanding of environmental, ecological, and evolutionary change across the Americas. To bring clarity to the question of when the Isthmus of Panama formed, we provide an exhaustive review and reanalysis of geological, paleontological, and molecular records. These independent lines of evidence converge upon a cohesive narrative of gradually emerging land and constricting seaways,withformationof theIsthmus of Panama sensustricto around 2.8 Ma. The evidence used to support an older isthmus is inconclusive, and we caution against the uncritical acceptance of an isthmus before the Pliocene., Facultad de Ciencias Naturales y Museo