Incidence of pregnancy loss and characterization of fetal development in red pandas

Previous reports indicate that red pandas (Ailurus fulgens styani) may experience fetal loss during gestation; however, neither the rate nor timing of pregnancy failure has been described in this species. The objective of the current study was to utilize ultrasound video and images collected between 2010-2020 at the Cincinnati Zoo and Botanical Garden to better characterize pregnancy loss and fetal development. Trans-abdominal ultrasound examinations were performed on six female red pandas over a 10-year period, resulting in 12 profiles. Pregnancy was diagnosed via ultrasound in all profiles in which cubs were produced (n = 8) and in two profiles in which cubs were not produced. Two additional females did not produce cubs and no concepti were discernible via ultrasound. Fetal loss was documented in 40.0% of pregnancies and was classified into Lost (2 of 10; 20.0%), in which no cubs were produced, or Partial Loss (2 of 10; 20.0%), in which two concepti were visualized via ultrasound, but only one cub was born. Fetal loss occurred between days 51 and 23 pre-partum. Fetal growth characteristics were documented, including skeletal ossification (occurring between day 32 and 27 pre-partum), crown-rump length, head length, cranial length, and fetal heart rate (173-206 beats per minute). These findings provide novel insights into pregnancy loss, may serve as a reference for milestones of fetal development, and may be useful in diagnosing pregnancy and assessing pregnancy loss in red pandas.

How the Ends of Bones Evolve and What They Do: The Anatomical and Biomechanical Perspective

Skeletal ossification occurs either directly within mesenchymal tissues or indirectly through a template of hyaline cartilage. Between the epiphyses and diaphyses of long bones, hyaline cartilaginous growth plates remain and constitute the progenitor cell reservoir from which the tissue develops toward the diaphysis and determines longitudinal bone size. Growth plates exhibit a characteristic architecture with columnar cell organization and different zonal morphology. The cells increase their volume toward the diaphysis, and eventually the longitudinally arranged septa of extracellular matrix mineralize. Finally, the mineralized cartilage matrix is replaced by lamellar bone. The extracellular matrix is rich in glycosaminoglycans, proteoglycans, and collagen II; at the edges of the growth plates, collagen I, III, and collagen X, especially at the mineralization front, are also present.The geometry of the growth plates is regulated by the local mechanical environment. In general, all plates orient themselves perpendicular to the resulting compressive force vector; grooves, ridges, and lateral angulations are adaptations to withstand shear forces acting on the growth plates. The final shape of the fully grown bone is determined not only by the epiphyseal growth plates but also by their apophyseal counterpart. Both structures respond in a comparable fashion to the local mechanical environment.

Hips, tips and sweet sweptback rays: Looking beyond traditional cranial characters in Pachycormiformes

A focus on cranial characters for determining relatedness is a predominant trait in many datasets, however this overemphasis can lead to distortion from sampler bias. We report on revised analyses of pachycormids - a key group within Actinopterygii, as part of the Holostei-Teleostei transition, which display a phyletic trend towards reduced skeletal ossification with the increased adult size of a pachycormid taxon. This reduced preservation potential for the axial skeleton makes it difficult not to base phylogenetic assumptions primarily on the limited skull material present. However, pachycormids show a remarkable conservatism in their dermatocranial anatomy, the few differences being useful for showing the separation of genera, but of little utility in working out broader intrafamilial relationships. The combination of a paucity of postcranial characters in the Late Cretaceous pursuit predator Protosphyraena with a poor knowledge about the skulls of suspension-feeding pachycormids (SFPs) had led to the absence of Early Cretaceous predatory pachycormids being interpreted as indicating a ghost lineage between Protosphyraena and the European Upper Jurassic taxa Orthocormus and Hypsocormus over an almost 50-million-year gap. However, the inclusion of several features from the pectoral and pelvic fins, supplemented by splanchnocranial characters, produces a much clearer picture that questions the traditional perception of a single carnivore lineage: Protosphyraena emerges as secondarily carnivorous from the SFPs’ tribe, mirroring 130 years of misidentification of North American Bonnerichthys specimens as Protosphyraena. Confirmation of this will rely on the further recovery of data concerning the skull morphology of SFPs.

Hips, tips and sweet sweptback rays: Looking beyond traditional cranial characters in Pachycormiformes

A focus on cranial characters for determining relatedness is a predominant trait in many datasets, however this overemphasis can lead to distortion from sampler bias. We report on revised analyses of pachycormids - a key group within Actinopterygii, as part of the Holostei-Teleostei transition, which display a phyletic trend towards reduced skeletal ossification with the increased adult size of a pachycormid taxon. This reduced preservation potential for the axial skeleton makes it difficult not to base phylogenetic assumptions primarily on the limited skull material present. However, pachycormids show a remarkable conservatism in their dermatocranial anatomy, the few differences being useful for showing the separation of genera, but of little utility in working out broader intrafamilial relationships. The combination of a paucity of postcranial characters in the Late Cretaceous pursuit predator Protosphyraena with a poor knowledge about the skulls of suspension-feeding pachycormids (SFPs) had led to the absence of Early Cretaceous predatory pachycormids being interpreted as indicating a ghost lineage between Protosphyraena and the European Upper Jurassic taxa Orthocormus and Hypsocormus over an almost 50-million-year gap. However, the inclusion of several features from the pectoral and pelvic fins, supplemented by splanchnocranial characters, produces a much clearer picture that questions the traditional perception of a single carnivore lineage: Protosphyraena emerges as secondarily carnivorous from the SFPs’ tribe, mirroring 130 years of misidentification of North American Bonnerichthys specimens as Protosphyraena. Confirmation of this will rely on the further recovery of data concerning the skull morphology of SFPs.