No abstract

Background and aims – Diatoms began to inhabit freshwater by at least the Late Cretaceous, becoming well established by the early to middle Eocene. Aulacoseira, an important diatom in numerous ponds, lakes and rivers today, was one of the earliest known genera to colonize freshwater ecosystems. Members of this genus with characteristics familiar to those found on modern species became increasingly more abundant by the Eocene, and continued to thrive throughout the Miocene to the present. We describe a new species of Aulacoseira from an early to middle Eocene site near the Arctic Circle in northern Canada. Methods – Twelve samples taken from the Giraffe Pipe core were analysed in this study. Light and scanning electron microscopy were used to document morphological characters. Morphometric measurements were made from 200 specimens per sample (n = 1200), and used to investigate changes in valve size over time. Key results – The new species, Aulacoseira giraffensis, has valves with a length:width ratio close to 1, a hyaline valve face, straight mantle striae, a shallow ringleiste, branched linking spines, concave-convex complementarity on adjacent valve faces, and rimoportulae with simple papillae-like structure. The suite of characters, especially the highly branched spines, concave-convex valves and simple rimoportulae, is unique for this species. Large numbers of A. giraffensis specimens were found over a ten-metre section of the core, representing thousands of years. These high concentrations are indicative of abundant, bloom-like, growth. Conclusions – The locality represents one of the earliest known records of Aulacoseira dominating a freshwater community. Findings confirm that the morphological body plan for the genus was well established by the Eocene. Although findings indicate evolutionary stasis in morphological structure for A. giraffensis over a time scale of thousands of years, oscillations in valve morphometrics could potentially be used to trace changes in the environment of this ancient Arctic waterbody.

This study aimed to determine the age groups, breeds, and morphological characteristics of horses used in vaquejada competitions, as well as to define how often the animals compete, the results achieved in the contests, and the duration of training. A sample of 1,271 horses used in vaquejada competitions was employed in the study. The first step consisted in interviewing owners to obtain information on the age and breed of the horses, vaquejada circuits in which they compete, frequency of competition in vaquejada, results reached in the trials, and training duration per month, week, and day. The second step obtained 15 linear measurements and calculated eight morphometric indices. The data obtained from the interviews were submitted to descriptive statistical analyses. The linear measurements and morphometric indices were used to compare sexes using a completely randomized experimental design. The results showed that 80.3% of the vaquejada horses were between four and ten years old and that 89% of the animals were of the Quarter Horse. The morphometric measures showed that stallions had higher height at withers, back, and croup and wider heads, chest, and croup than mares and geldings. On the other hand, among the eight indices calculated, only the value of the height at the chest of the stallions was higher than the mean values in mares and geldings. It was found that 79.7% of the horses took part in two to four vaquejada trials a month while 93.3% of the animals underwent fitness training 12 months a year. The results show a predominance of Quarter Horses in the vaquejada contests in Pernambuco and that the trials require the selection of physically larger and stronger stallions. In addition, the animals are submitted to intense training and competition routines.

This study aimed to determine the frequency of biometric alterations in thoracic limbs of vaquejada horses. A sample of 1,270 horses of either sex and different age groups competing in vaquejada as either puxador (leading) or esteira (trailing) roles were used. Measurements were made of body length, thoracic circumference, and circumferences of the forearm, knee, cannon, fetlock, and pastern of the right- and left-side thoracic limbs. Asymmetry in the five regions of thoracic limbs was also determined by calculating the difference between the right- and left-side circumferences of each region. Physical examination was conducted in 598 horses by palpating the knee, cannon, fetlock, and pastern to identify possible orthopedic alterations. The results of the differences between the circumferences of thoracic limbs of either side were submitted to Kruskal-Wallis test and the prevalence of orthopedic alterations was compared by frequency distribution test. Asymmetry was observed between the right- and left-side thoracic limbs in 99.3% of horses, especially in the forearm. Of the 598 horses examined via palpation, 481 individuals (80.4%) exhibited orthopedic alterations in at least one of the four regions examined, with the highest prevalence of alterations in the cannon and fetlock. In addition, the proportions of individuals with orthopedic alterations increased linearly with age, while higher values in the conformation and dactyl-thoracic indices also resulted in higher prevalence of alterations. It was concluded that the frequency of biometric alterations in thoracic limbs of vaquejada horses is high.