A Southern Hemisphere origin for campanulid angiosperms, with traces of the break-up of Gondwana

Background New powerful biogeographic methods have focused attention on long-standing hypotheses regarding the influence of the break-up of Gondwana on the biogeography of Southern Hemisphere plant groups. Studies to date have often concluded that these groups are too young to have been influenced by these ancient continental movements. Here we examine a much larger and older angiosperm clade, the Campanulidae, and infer its biogeographic history by combining Bayesian divergence time information with a likelihood-based biogeographic model focused on the Gondwanan landmasses. Results Our analyses imply that campanulids likely originated in the middle Albian (~105 Ma), and that a substantial portion of the early evolutionary history of campanulids took place in the Southern Hemisphere, despite their greater species richness in the Northern Hemisphere today. We also discovered several disjunctions that show biogeographic and temporal correspondence with the break-up of Gondwana. Conclusions While it is possible to discern traces of the break-up of Gondwana in clades that are old enough, it will generally be difficult to be confident in continental movement as the prime cause of geographic disjunctions. This follows from the need for the geographic disjunction, the inferred biogeographic scenario, and the dating of the lineage splitting events to be consistent with the causal hypothesis

Incongruence in molecular species delimitation schemes: What to do when adding more data is difficult

Using multiple, independent approaches to molecular species delimitation is advocated to accommodate limitations and assumptions of a single approach. Incongruence in delimitation schemes is a potential byâ product of employing multiple methods on the same data, and little attention has been paid to its reconciliation. Instead, a particular scheme is prioritized, and/or molecular delimitations are coupled with additional, independent lines of evidence that mitigate incongruence. We advocate that incongruence within a line of evidence should be accounted for before comparing across lines of evidence that can themselves be incongruent. Additionally, it is not uncommon for empiricists working in nonmodel systems to be dataâ limited, generating some concern for the adequacy of available data to address the question of interest. With conservation and management decisions often hinging on the status of species, it seems prudent to understand the capabilities of approaches we use given the data we have. Here, we apply two molecular species delimitation approaches, spedeSTEM and BPP, to the Castilleja ambigua (Orobanchaceae) species complex, a relatively young plant lineage in western North America. Upon finding incongruence in our delimitation, we employed a post hoc simulation study to examine the power of these approaches to delimit species. Given the data we collected, we find that spedeSTEM lacks the power to delimit while BPP is capable, thus allowing us to address incongruence before proceeding in delimitation. We suggest post hoc simulation studies like this compliment empirical delimitation and serve as a means of exploring conflict within a line of evidence and dealing with it appropriately.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144255/1/mec14590_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144255/2/mec14590.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144255/3/mec14590-sup-0001-DataS1-S7.pd

Oligocene niche shift, Miocene diversification – cold tolerance and accelerated speciation rates in the St. John’s Worts (Hypericum, Hypericaceae)

Background: Our aim is to understand the evolution of species-rich plant groups that shifted from tropical into cold/temperate biomes. It is well known that climate affects evolutionary processes, such as how fast species diversify, species range shifts, and species distributions. Many plant lineages may have gone extinct in the Northern Hemisphere due to Late Eocene climate cooling, while some tropical lineages may have adapted to temperate conditions and radiated; the hyper-diverse and geographically widespread genus Hypericum is one of these. Results: To investigate the effect of macroecological niche shifts on evolutionary success we combine historical biogeography with analyses of diversification dynamics and climatic niche shifts in a phylogenetic framework. Hypericum evolved cold tolerance c. 30 million years ago, and successfully colonized all ice-free continents, where today ~500 species exist. The other members of Hypericaceae stayed in their tropical habitats and evolved into ~120 species. We identified a 15–20 million year lag between the initial change in temperature preference in Hypericum and subsequent diversification rate shifts in the Miocene. Conclusions: Contrary to the dramatic niche shift early in the evolution of Hypericum most extant species occur in temperate climates including high elevations in the tropics. These cold/temperate niches are a distinctive characteristic of Hypericum. We conclude that the initial release from an evolutionary constraint (from tropical to temperate climates) is an important novelty in Hypericum. However, the initial shift in the adaptive landscape into colder climates appears to be a precondition, and may not be directly related to increased diversification rates. Instead, subsequent events of mountain formation and further climate cooling may better explain distribution patterns and species-richness in Hypericum. These findings exemplify important macroevolutionary patterns of plant diversification during large-scale global climate change

An operative approach to address severe genu valgum deformity in the Ellis-van Creveld syndrome

BACKGROUND: The genu valgum deformity seen in the Ellis-van Creveld syndrome is one of the most severe angular deformities seen in any orthopaedic condition. It is likely a combination of a primary genetic-based dysplasia of the lateral portion of the tibial plateau combined with severe soft-tissue contractures that tether the tibia into valgus deformations. Progressive weight-bearing induces changes, accumulating with growth, acting on the initially distorted and valgus-angulated proximal tibia, worsening the deformity with skeletal maturation. The purpose of this study is to present a relatively large case series of a very rare condition that describes a surgical technique to correct the severe valgus deformity in the Ellis-van Creveld syndrome by combining extensive soft-tissue release with bony realignment. METHODS: 1. Complete proximal to distal surgical decompression of the peroneal nerve. 2. Radical release and mobilization of the severe quadriceps contracture and iliotibial band contracture. 3. Distal lateral hamstring lengthening/tenotomy and lateral collateral ligament release. 4. Proximal and distal realignment of the subluxed/dislocated patella, medial and lateral retinacular release, vastus medialis advancement, patellar chondroplasty, medial patellofemoral ligament plication, and distal patellar realignment by Roux-Goldthwait technique or patellar tendon transfer with tibial tubercle relocation. 5. Proximal tibial varus osteotomy with partial fibulectomy and anterior compartment release. 6. Occasionally, distal femoral osteotomy. RESULTS: In all cases, the combination of radical soft-tissue release, patellar realignment and bony osteotomy resulted in 10° or less of genu valgum at the time of surgical correction. Complications of surgery included three patients (five limbs) with knee stiffness that was successfully manipulated, one peroneal nerve palsy, one wound slough and hematoma requiring a skin graft, and one pseudoarthrosis requiring removal of hardware and repeat fixation. At last follow-up, radiographic correction of no more than 20° of genu valgum was maintained in all but four patients (four limbs). Two patients (three limbs) had or currently require revision surgery due to recurrence of the deformity. CONCLUSION: The operative approach presented in this study has resulted in correction of the severe genu valgum deformity in Ellis-van Creveld syndrome to 10° or less of genu valgum at the time of surgery. Although not an outcomes study, a correction of no more than 20° genu valgum has been maintained in many of the cases included in the study. Further clinical follow-up is still warranted. LEVEL OF EVIDENCE: IV

Primers for Castilleja and their Utility Across Orobanchaceae: II. Single‐copy nuclear loci

Premise of the study: We developed primers targeting nuclear loci in Castilleja with the goal of reconstructing the evolutionary history of this challenging clade. These primers were tested across other major clades in Orobanchaceae to assess their broader utility.Methods and Results: We assembled low-coverage genomes for three taxa in Castilleja and developed primer combinations for the single-copy conserved ortholog set (COSII) and the pentatricopeptide repeat (PPR) gene family. These primer combinations were designed to take advantage of the Fluidigm microfluidic PCR platform and are well suited for high-throughput sequencing applications. Eighty-seven primers were designed for Castilleja, and 27 were found to have broader utility in Orobanchaceae.Conclusions: These results demonstrate the utility of these primers, not only across Castilleja, but for other lineages within Orobanchaceae as well. This expanded molecular toolkit will be an asset to future phylogenetic studies in Castilleja and throughout Orobanchaceae

Primers for Castilleja and their utility across Orobanchaceae: I. Chloroplast primers1

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141726/1/aps31700020.pd

Primers for Castilleja and their Utility Across Orobanchaceae: I. Chloroplast Primers

Premise of the study: Chloroplast primers were developed from genomic data for the taxonomically challenging genus Castilleja. We further tested the broader utility of these primers across Orobanchaceae, identifying a core set of chloroplast primers amplifying across the clade.Methods and Results: Using a combination of three low-coverage Castilleja genomes and sequence data from 12 Castilleja plastomes, 76 primer combinations were specifically designed and tested for Castilleja. The primers targeted the most variable portions of the plastome and were validated for their applicability across the clade. Of these, 38 primer combinations were subsequently evaluated in silico and then validated across other major clades in Orobanchaceae.Conclusions: These results demonstrate the utility of these primers, not only across Castilleja, but for other clades in Orobanchaceae— particularly hemiparasitic lineages—and will contribute to future phylogenetic studies of this important clade of parasitic plants

Sources of noise during accumulation of evidence in unrestrained and voluntarily head-restrained rats

Abstract Decision-making behavior is often characterized by substantial variability, but its source remains unclear. We developed a visual accumulation of evidence task designed to quantify sources of noise and to be performed during voluntary head restraint, enabling cellular resolution imaging in future studies. Rats accumulated discrete numbers of flashes presented to the left and right visual hemifields and indicated the side that had the greater number of flashes. Using a signaldetection theory-based model, we found that the standard deviation in their internal estimate of flash number scaled linearly with the number of flashes. This indicates a major source of noise that, surprisingly, is not consistent with the widely used 'drift-diffusion modeling' (DDM) approach but is instead closely related to proposed models of numerical cognition and counting. We speculate that this form of noise could be important in accumulation of evidence tasks generally