Comparative anatomy of the rostrosoma of Solifugae, Pseudoscorpiones and Acari

We compare the microscopic anatomy of the mouthparts of representative species of Solifugae, Pseudoscorpiones and Parasitiformes (Acari). Specifically, we focus on the epistome, the labrum, the lateral lips (= endites of the pedipalpal coxae) and the musculature of the pharyngeal suction pump. We provide evidence that the labrum is reduced in Solifugae, but present and functional in Pseudoscorpiones and Acari. The epistome constitutes the entire dorsal face of the rostrosoma in Solifugae, but is internalized into the prosoma in Pseudoscorpiones. In Acari, the epistome shows an ancestral morphology, probably close to the ground pattern of chelicerates. The lateral lips of Solifugae contribute to the ventral face of the rostrosoma and the two lips of the mouth opening. In Solifugae, the ventral rostrosoma also includes a sclerite that might derive from a tritosternum. In Pseudoscorpiones, the lateral lips remain independent of the rostrosoma, they interlock ventral to the rostrosoma forming a perioral space. Here, the rostrosoma has an unpaired ventral lip of unresolved morphological origin, which is, however, clearly distinct from the lateral lips of Solifugae. The pharyngeal suction pump differs in all three clades in attachment, number of muscles and origin of muscles. We interpret the data as evidence for independent, parallel evolution of elements of the ground pattern of the (eu)chelicerate mouth parts. Based on the morphological elements of a common euchelicerate ground plan, the rostrosoma evolved independently in the three clades. We reject earlier hypotheses that consider the rostrosoma a character to support a phylogenetic relationship of the three clades.

Comparative anatomy of selected bones of forelimb of local Mongrelian Dog (Canis lupus familiaris) in Sokoto, Nigeria

This research was conducted over period of 3 months with the aim of studying Age related changes of selected bones of forelimb (Scapula, Humerus, Radius and Ulna) in Local Mongrelian Dog (Canis lupus familiaris). The study entails biometrical and gross observations on the bones. The sample bones were acquired from the experimental animals of comparative anatomy in the department. The bones were categorized into various age groups for the research. The length, width, diameter and circumference of the samples (scapula, humerus, radius and ulna bones) were determined for all the groups. The shape, size, color, location, position and relation of each segment of the samples at various stages of development were determined. The differences across the age groups of different samples were observed and recorded. Based on the research result, it was concluded that, the biometric and morphometry data was found to be increasing with advancement of age. A baseline data was established with the view to enhance learning.

Le patrimoine scientifique des Invisibles. Reconsidérer les Petites–Mains au service de l’anatomie comparée au Muséum de Paris

Au sein du Muséum national d’histoire naturelle de Paris, les assistants naturalistes formaient une classe particulière au XIXe siècle. Ces employés produisaient une grande partie des collections de l’institution, contribuaient activement aux travaux des professeurs, et participaient même parfois à leur renommée. Néanmoins, ces assistants étaient plongés dans l’ombre des scientifiques, à tel point que nombre d’entre eux ont complètement disparu de la mémoire du Muséum. Dans certains cas, notamment pour les moulages d’après le vivant, leur travail est même attribué à de grandes personnalités, souvent à des professeurs. Les assistants naturalistes semblent historiographiquement peu étudiés; pourtant l’examen de ces employés à travers leurs productions matérielles permettrait de mieux comprendre l’histoire du Muséum et le développement de ses chaires. The Scientific Patrimony of the Invisibles: a Reconsideration of the Little Hands in the Service of Comparative Anatomy at the Muséum de Paris Within the Muséum national d’histoire naturelle of Paris, the assistant naturalists of the 19th century formed a particular class. These employees produced a large part of the institution’s collections, actively contributed to the work of the professors, and sometimes even participated in their renown. Nevertheless, these assistants were engulfed in the shadows of the scientists, to such an extent that many of them have completely disappeared from the memory of the Museum. In some cases, especially for life casts, their work is even attributed to the great personalities, often to professors. Assistant naturalists appear to be under–studied; yet the examination of these employees through their material productions would allow a better understanding of the Museum’s history and the development of its departments.

Comparative anatomy of dissected optic lobes, optic ventricles, midbrain tectum, collicular ventricles, and aqueduct: evolutionary modifications as potential explanation for non-tumoral aqueductal anomalies in humans

Purpose An extensive literature has postulated multiple etiologies for aqueductal stenosis. No publications were found, discussing that evolutionary modifications might explain aqueductal anomalies. This study’s objectives were to review the evolutionary modifications of vertebrates’ tectum structures that might explain human aqueduct anomalies. Undertaking vertebrate comparative study is currently not feasible in view of limitations in obtaining vertebrate material. Thus, vertebrate material collected, injected, dissected, and radiographed in the early 1970s was analyzed, focusing on the aqueduct and components of the midbrain tectum. Methods Photographs of brain dissections and radiographs of the cerebral ventricles and arteries of adult shark, frog, iguana, rabbit, cat, dog, and primate specimens, containing a barium-gelatin radiopaque compound, were analyzed focusing on the aqueduct, the optic ventricles, the quadrigeminal plate, and collicular ventricles. The anatomic information provided by the dissections and radiographs is not reproducible by any other radiopaque contrast currently available. Results Dissected and radiographed cerebral ventricular and arterial systems of the vertebrates demonstrated midbrain tectum changes, including relative size modifications of the mammalian components of the tectum, simultaneously with the enlargement of the occipital lobe. There is a transformation of pre-mammalian optic ventricles to what appear to be collicular ventricles in mammals, as the aqueduct and collicular ventricle form a continuous cavity. Conclusions The mammalian tectum undergoes an evolutionary cephalization process consisting of relative size changes of the midbrain tectum structures. This is associated with enlargement of the occipital lobe, as part of overall neocortical expansion. Potentially, aqueductal anomalies could be explained by evolutionary modifications.