Dataset Information

A revised cranial description of Massospondylus carinatus Owen (Dinosauria: Sauropodomorpha) based on computed tomographic scans and a review of cranial characters for basal Sauropodomorpha.

ABSTRACT: Massospondylus carinatus is a basal sauropodomorph dinosaur from the early Jurassic Elliot Formation of South Africa. It is one of the best-represented fossil dinosaur taxa, known from hundreds of specimens including at least 13 complete or nearly complete skulls. Surprisingly, the internal cranial anatomy of M. carinatus has never been described using computed tomography (CT) methods. Using CT scans and 3D digital representations, we digitally reconstruct the bones of the facial skeleton, braincase, and palate of a complete, undistorted cranium of M. carinatus (BP/1/5241). We describe the anatomical features of the cranial bones, and compare them to other closely related sauropodomorph taxa such as Plateosaurus erlenbergiensis, Lufengosaurus huenei, Sarahsaurus aurifontanalis and Efraasia minor. We identify a suite of character states of the skull and braincase for M. carinatus that sets it apart from other taxa, but these remain tentative due to the lack of comparative sauropodomorph braincase descriptions in the literature. Furthermore, we hypothesize 27 new cranial characters useful for determining relationships in non-sauropodan Sauropodomorpha, delete five pre-existing characters and revise the scores of several existing cranial characters to make more explicit homology statements. All the characters that we hypothesized or revised are illustrated. Using parsimony as an optimality criterion, we then test the relationships of M. carinatus (using BP/1/5241 as a specimen-level exemplar) in our revised phylogenetic data matrix.

SUBMITTER: Chapelle KEJ

PROVIDER: S-EPMC5768178 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A revised cranial description of Massospondylus carinatus Owen (Dinosauria: Sauropodomorpha) based on computed tomographic scans and a review of cranial characters for basal Sauropodomorpha.

Chapelle Kimberley E J KEJ Choiniere Jonah N JN

PeerJ 20180112

Massospondylus carinatus is a basal sauropodomorph dinosaur from the early Jurassic Elliot Formation of South Africa. It is one of the best-represented fossil dinosaur taxa, known from hundreds of specimens including at least 13 complete or nearly complete skulls. Surprisingly, the internal cranial anatomy of M. carinatus has never been described using computed tomography (CT) methods. Using CT scans and 3D digital representations, we digitally reconstruct the bones of the facial s ...[more]

PMID: 29340238

Similar Datasets

Project description:A 2009 randomized clinical trial demonstrated that using cancer antigen 125 (CA-125) tests for routine surveillance in ovarian cancer increases the use of chemotherapy and decreases patients' quality of life without improving survival, compared with clinical observation. The Society of Gynecologic Oncology guidelines categorize CA-125 testing as optional and discourage the use of radiographic imaging for routine surveillance. To date, few studies have examined the use of CA-125 tests in clinical practice.To examine the use of CA-125 tests and computed tomographic (CT) scans in clinical practice before and after the 2009 randomized clinical trial and to estimate the economic effect of surveillance testing.A prospective cohort of 1241 women with ovarian cancer in clinical remission after completion of primary cytoreductive surgery and chemotherapy at 6 National Cancer Institute-designated cancer centers between January 1, 2004, and December 31, 2011, was followed up through December 31, 2012, to study the use of CA-125 tests and CT scans before and after 2009. Data analysis was conducted from April 9, 2014, to March 28, 2016.The use of CA-125 tests and CT scans before and after 2009. Secondary outcomes included the time from CA-125 markers doubling to retreatment among women who experienced a rise in CA-125 markers before and after 2009, and the costs associated with surveillance testing using 2015 Medicare reimbursement rates.Among 1241 women (mean [SD] age 59 [12] years; 1112 white [89.6%]), the use of CA-125 testing and CT scans was similar during the study period. During 12 months of surveillance, the cumulative incidence of patients undergoing 3 or more CA-125 tests was 86% in 2004-2009 vs 91% in 2010-2012 (P?=?.95), and the cumulative incidence of patients undergoing more than 1 CT scan was 81% in 2004-2009 vs 78% in 2010-2012 (P?=?.50). Among women whose CA-125 markers doubled (n?=?511), there was no significant difference in the time to retreatment with chemotherapy before and after 2009 (median, 2.8 vs 3.5 months; P?=?.40). During a 12-month period, there was a mean of 4.6 CA-125 tests and 1.7 CT scans performed per patient, resulting in a US population surveillance cost estimate of $1?999?029 per year for CA-125 tests alone and $16?194?647 per year with CT scans added.CA-125 tests and CT scans are still routinely used for surveillance testing in patients with ovarian cancer, although their benefit has not been proven and their use may have significant implications for patients' quality of life as well as costs.

Project description:Parathyroid 4-dimensional computed tomographic scans (4D-CTs) have emerged as an accurate and cost-effective initial localization study for patients with primary hyperparathyroidism. However, potential limitations and factors affecting the accuracy of preoperative 4D-CTs remain poorly defined.To characterize factors associated with missed parathyroid lesions on preoperative 4D-CTs and to investigate patterns of commonly observed errors.A prospectively accrued patient database was analyzed from September 1, 2011, through October 31, 2016. The study was performed in a tertiary referral center. Consecutive patients with primary hyperparathyroidism undergoing preoperative 4D-CTs and subsequent parathyroidectomy were included in the study.Discordance between preoperative 4D-CTs and intraoperative findings in the number and location of abnormal parathyroid lesions.Of 411 patients studied (mean [SD] age, 59 [14] years; 325 [79.1%] female), 123 (29.9%) had discordance between preoperative 4D-CTs and intraoperative findings. Among the 411 patients, 75 (18.2%) had major discordance, including incorrectly localized adenoma on the contralateral side of the neck, missed double adenoma, and absence of any abnormal lesion detected on 4D-CTs. Compared with concordant cases, discordant cases had higher frequencies of multigland disease (66.7% [82 of 123] vs 24.3% [70 of 288], P?<?.001) and multinodular goiter or thyroid nodule (40.7% [50 of 123] vs 29.2% [84 of 288], P?=?.02). Missed parathyroid lesions were smaller (mean [SD], 0.86 [0.29] vs 1.24 [0.50] cm; P?<?.001) and were more likely to be in the inferior position (65.4% [87 of 133] vs 38.1% [177 of 465], P?<?.001). Parathyroid lesion size of 10 mm or less (odds ratio [OR], 4.37; 95% CI, 2.24-8.54), multigland disease (OR, 7.63; 95% CI, 3.49-16.69), multinodular goiter or thyroid nodule (OR, 1.82; 95% CI, 1.01-3.28), and parathyroid lesion in the inferior position (OR, 6.82; 95% CI, 3.10-14.99) were independently associated with discordant 4D-CT results.Multigland disease was most strongly associated with discordance between preoperative 4D-CTs and intraoperative findings, followed by parathyroid lesion in the inferior position and parathyroid lesion size of 10 mm or less. Awareness of these potential pitfalls may allow surgeons to better leverage this new localization technique in preoperative planning and intraoperative troubleshooting.

Project description:Despite the increasing importance of molecular sequence data, morphology still makes an important contribution to resolving the phylogeny of many groups, and is the only source of data for most fossils. Most systematists sample morphological characters as broadly as possible on the principle of total evidence. However, it is not uncommon for sampling to be focused on particular aspects of anatomy, either because characters therein are believed to be more informative, or because preservation biases restrict what is available. Empirically, the optimal trees from partitions of morphological data sets often represent significantly different hypotheses of relationships. Previous work on hard-part versus soft-part characters across animal phyla revealed significant differences in about a half of sampled studies. Similarly, studies of the craniodental versus postcranial characters of vertebrates revealed significantly different trees in about one-third of cases, with the highest rates observed in non-avian dinosaurs. We test whether this is a generality here with a much larger sample of 81 published data matrices across all major dinosaur groups. Using the incongruence length difference test and two variants of the incongruence relationship difference test, we found significant incongruence in about 50% of cases. Incongruence is not uniformly distributed across major dinosaur clades, being highest (63%) in Theropoda and lowest (25%) in Thyreophora. As in previous studies, our partition tests show some sensitivity to matrix dimensions and the amount and distribution of missing entries. Levels of homoplasy and retained synapomorphy are similar between partitions, such that incongruence must partly reflect differences in patterns of homoplasy between partitions, which may itself be a function of modularity and mosaic evolution. Finally, we implement new tests to determine which partition yields trees most similar to those from the entire matrix. Despite no bias across dinosaurs overall, there are striking differences between major groups. The craniodental characters of Ornithischia and the postcranial characters of Saurischia yield trees most similar to the "total evidence" trees derived from the entire matrix. Trees from these same character partitions also tend to be most stratigraphically congruent: a mutual consilience suggesting that those partitions yield more accurate trees. [Dinosauria; homoplasy; partition homogeneity.].

Dataset Information

A revised cranial description of Massospondylus carinatus Owen (Dinosauria: Sauropodomorpha) based on computed tomographic scans and a review of cranial characters for basal Sauropodomorpha.

Publications

A revised cranial description of <i>Massospondylus carinatus</i> Owen (Dinosauria: Sauropodomorpha) based on computed tomographic scans and a review of cranial characters for basal Sauropodomorpha.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets