A new vertebrate fauna from the Lower Cretaceous Holly Creek Formation of the Trinity Group, southwest Arkansas, USA.

We present a previously discovered but undescribed late Early Cretaceous vertebrate fauna from the Holly Creek Formation of the Trinity Group in Arkansas. The site from the ancient Gulf Coast is dominated by semi-aquatic forms and preserves a diverse aquatic, semi-aquatic, and terrestrial fauna. Fishes include fresh- to brackish-water chondrichthyans and a variety of actinopterygians, including semionotids, an amiid, and a new pycnodontiform, Anomoeodus caddoi sp. nov. Semi-aquatic taxa include lissamphibians, the solemydid turtle Naomichelys, a trionychid turtle, and coelognathosuchian crocodyliforms. Among terrestrial forms are several members of Dinosauria and one or more squamates, one of which, Sciroseps pawhuskai gen. et sp. nov., is described herein. Among Dinosauria, both large and small theropods (Acrocanthosaurus, Deinonychus, and Richardoestesia) and titanosauriform sauropods are represented; herein we also report the first occurrence of a nodosaurid ankylosaur from the Trinity Group. The fauna of the Holly Creek Formation is similar to other, widely scattered late Early Cretaceous assemblages across North America and suggests the presence of a low-diversity, broadly distributed continental ecosystem of the Early Cretaceous following the Late Jurassic faunal turnover. This low-diversity ecosystem contrasts sharply with the highly diverse ecosystem which emerged by the Cenomanian. The contrast underpins the importance of vicariance as an evolutionary driver brought on by Sevier tectonics and climatic changes, such as rising sea level and formation of the Western Interior Seaway, impacting the early Late Cretaceous ecosystem.

Rhabdomyolysis After Total Abdominal Hysterectomy Requiring Urgent Hemodialysis Due to Hyperkalemia.

A 63-year-old woman with a past medical history of invasive ductal carcinoma of the breast, status post lumpectomy and chemoradiation, 15 cm left inguinal-femoral enlarged lymph node consistent with high-grade serous carcinoma of the ovary and 4.7 cm right adnexal mass underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymph node dissection with cystoscopy and bilateral ureteral catheter placement. There was no intraoperative complication. After surgery, patient's urine output decreased, and she developed acute kidney injury (AKI). Initially, it was thought that her reduced output might be due to surgery/anesthesia. She also developed arm and leg weakness raising suspicion for stroke. The neurological workup was unremarkable for any acute abnormality. Her creatinine kinase (CK) level was >20,000 u/l consistent with rhabdomyolysis. She was hydrated aggressively and required hemodialysis due to hyperkalemia. During the hospital course, her kidney function improved, and rhabdomyolysis resolved, and she did not require dialysis after discharge.

A gigantic shark from the lower cretaceous duck creek formation of Texas.

Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks. Regardless of its actual identification, this new specimen provides further evidence that large-bodied lamniform sharks had evolved prior to the Late Cretaceous.

Craniofacial ontogeny in Centrosaurus apertus.

Centrosaurus apertus, a large bodied ceratopsid from the Late Cretaceous of North America, is one of the most common fossils recovered from the Belly River Group. This fossil record shows a wide diversity in morphology and size, with specimens ranging from putative juveniles to fully-grown individuals. The goal of this study was to reconstruct the ontogenetic changes that occur in the craniofacial skeleton of C. apertus through a quantitative cladistic analysis. Forty-seven cranial specimens were independently coded in separate data matrices for 80 hypothetical multistate growth characters and 130 hypothetical binary growth characters. Both analyses yielded the max-limit of 100,000 most parsimonious saved trees and the strict consensus collapsed into large polytomies. In order to reduce conflict resulting from missing data, fragmentary individuals were removed and the analyses were rerun. Among both the complete and the reduced data sets the multistate analyses recovered a shorter tree with a higher consistency index (CI) than the additive binary data sets. The arrangement within the trees shows a progression of specimens with a recurved nasal horn in the least mature individuals, followed by specimens with straight nasal horns in relatively more mature individuals, and finally specimens with procurved nasal horns in the most mature individuals. The most mature individuals are further characterized by the reduction of the cranial horn ornamentations in late growth stages, a trait that similarly occurs in the growth of other dinosaurs. Bone textural changes were found to be sufficient proxies for relative maturity in individuals that have not reached adult size. Additionally, frill length is congruent with relative maturity status and makes an acceptable proxy for ontogenetic status, especially in smaller individuals. In adult-sized individuals, the fusion of the epiparietals and episquamosals and the orientation of the nasal horn are the best indicators of relative maturity. This study recovers no clear evidence for sexually specific display structures or size dimorphism in C. apertus.