Rapid evolution of the primate larynx?

Tissue vibrations in the larynx produce most sounds that comprise vocal communication in mammals. Larynx morphology is thus predicted to be a key target for selection, particularly in species with highly developed vocal communication systems. Here, we present a novel database of digitally modeled scanned larynges from 55 different mammalian species, representing a wide range of body sizes in the primate and carnivoran orders. Using phylogenetic comparative methods, we demonstrate that the primate larynx has evolved more rapidly than the carnivoran larynx, resulting in a pattern of larger size and increased deviation from expected allometry with body size. These results imply fundamental differences between primates and carnivorans in the balance of selective forces that constrain larynx size and highlight an evolutionary flexibility in primates that may help explain why we have developed complex and diverse uses of the vocal organ for communication.

Third eyelid in the small Indian mongoose (Herpestes javanicus): a morphological and histological study

The Indian mongoose (Herpestes javanicus) is native to parts of Asia, Iran. The purpose of this study was to describe the gross anatomy of the cartilage and histology of the superficial gland of the third eyelid of two adult mongooses. The animals, in terminal stages of disease and near death due to aging or unknown reasons, were referred from Park Zoo (Shiraz, Iran) to our center. By using a modified maceration technique, the morphological characteristics of the cartilage were examined. For histological examinations of the superficial gland of the third eyelid, the samples were stained with haematoxylin and eosin. Also, to detect the elastic fibers in the cartilage sections were stained with orcein and Weigert's resorcin-fuchsin. The cartilage consisted of an ovoid appendix and a mild reverse sigmoid crossbar. Elastic fibers were scattered throughout the cartilage but were more concentrated in the center. The superficial gland of the third eyelid was compound tubuloacinar with serous acini.

The earliest modern mongoose (Carnivora, Herpestidae) from Africa (late Miocene of Chad)

We report on the earliest modern mongooses of Africa, from the late Miocene (ca. 7 Ma) of the hominid locality TM 266, Toros-Menalla, Chad. The material is based on fragmentary dentitions of three individuals. The main diagnostic feature of the Chadian species is the great development of the shear in the carnassials, which distinguishes the Chadian specimens from all extant herpestids except Herpestes and Galerella. In comparison with most extinct and extant Herpestes, the species from Toros-Menalla differs by a markedly smaller size and, depending on the species, relatively more elongated carnassials, more transversely elongated M1 and more reduced p4. On the basis of a great morphological similarity and the absence of significant differences, we assign our material to Galerella sanguinea; the Chadian finding therefore represents the earliest appearance of an extant species of Herpestidae. This record ties the first appearance of the genus to a minimum age of ca. 7 Ma, which is consistent with the estimated divergence date of 11.4 Ma known from the literature for the species of Galerella.

Fine structure of the dorsal epithelium of the mongoose tongue

The epithelium of the lingual dorsum of the mongoose, Herpestes edwardsi, was composed of two main areas: the interpapillary area, characterised by the absence of keratinisation; and the papillary area, characterised by hard keratinisation. The number of tonofibrils in the cytoplasm gradually increased, and the volume of the individual cells also increased, from the germinal layer to the intermediate layer of the interpapillary epithelium. No keratohyalin granules were recognised in these cells. In the cells of the surface layer of the interpapillary epithelium, most of the cytoplasm was filled with tonofilaments. The germinal layer of the papillary epithelium was almost identical to that of the interpapillary epithelium. In the intermediate layer, three different types of keratohyalin granule were apparent. The first type consisted of loosely aggregated ribosomes and had moderate electron density. The second type consisted of electron-dense granules derived from granules of the first type. The third type consisted of conjugated structures made up of tonofibrils, which were embedded in electron-dense material. Free ribosomes gradually disappeared as the keratinised layer was approached and most of the cytoplasm of cells in this layer was filled with keratin fibres.

Comparative studies of the dorsal surface of the tongue in three mammalian species by scanning electron microscopy

Comparative features of the dorsal tongue epithelia in musk shrews, mongooses and rats were described. The shapes of the filiform papillae were different in each of the species. The distribution pattern of filiform papillae was similar both in the musk shrews and mongoose, in that the form of filiform papillae changed gradually from the lingual apex to the posterior part of the lingual body. By contrast, the different types of filiform papillae were distributed on definite areas of the dorsal lingual surface in the rat. Microridges on the interpapillar surface in the musk shrew and mongoose presented a clear outline, but those of the rat were not so distinct. In all species, the upper surface of filiform papillae did not show any distinct microridges.

Histochemistry of mucosubstances in the lingual glands of the mongoose

The histochemistry of mucosubstances in the lingual glands of the mongoose was studied. Both serous and mucous or mixed glands were present in the posterior part of the tongue. In serous glands, acinar cells and occasional duct cells contained granules which gave reactions for neutral mucosubstances only. In mucous glands, tubular cells, acinar cells and duct cells all contained weakly sulphated mucosubstances. Demilune cells contained neutral mucosubstances. Occasional demilune cells contained weakly sulphated mucosubstances. Carboxylated mucosubstances (sialomucins) were not found in the lingual glands.

Histology and mucosubstance histochemistry of mongoose salivary glands

The histology and mucosubstance histochemistry of the mongoose salivary glands were studied. Histologically, the mongoose salivary glands were generally similar to those in other carnivores (dog, cat and ferret). The mucosubstance histochemistry demonstrated considerable variations in the parotid, submandibular and sublingual glands in comparison to the other carnivores. The partoid gland contained carboxylated mucin which was sialidase-resistant. Granules in a few cells also contained sulphated mucin. Both submandibular and sublingual glands contained mainly carboxylated sialomucin which was sialidase-labile except in a few cell, some neutral mucin but no sulphated mucin. The molar and zygomatic glands were similar to those in the other carnivores. They contained both sulphated and carboxylated mucins but no neutral mucin. The carboxylated mucin was sialidase-resistant.

Studies on the innervation of the endometrium

The innervation of the endometrium of rabbit, rat, mink, mongoose and pig has been investigated electron microscopically. Large bundles of nerve fibers can be observed in the connective tissue spaces within the basal layer of the endometrium. Unmyelinated nerve fibers enter the lamina functionalis, terminal nerve fibers penetrate the basal lamina and make contact with the glandular and the cavum epithelial cells. The terminal axons contain abundant synaptic vesicles, dense core vesicles and mitochondria. To date, no specialized presynaptic or postsynaptic membranes have been found.

A long-term comparative study of the mammalian larynx, based on whole organ serial sectioning

The paper includes brief details of a long term three-dimensional study into the fine structure of the mammalian larynx using whole organ serial sections. Differential staining, including Glees silver technique, is essential if maximum information is to be gained. A specially designed punch card will enable any future investigator to rapidly retrieve relevant information and it is expected that specimens of all available mammalian larynges will be included. Illustrations are included in this paper of the cat, dog, horse and mongoose.

Calcitonin cells and unusual follicles of the thyroid of the indian grey mongoose, Herpestes edwardsi (Geoffroy)

Histological preparations of thyroid, parathyroid and thymus glands of Herpestes edwardsi were examined for calcitonin cells. They reveal that (1) the thyroid calcitonin cells are oval, rounded and rarely elongated in shape; these cells and their nuclei are distinctly larger than those of the follicular cells and their nuclei; (2) calcitonin cells are unevenly distributed in the thyroid, with the result that certain portions of the thyroid are completely devoid of these cells; (3) on an average, calcitonin cells are in a ratio of 10-15 cells/100 follicular cells; (4) the parathyroid and thymus glands do not display calcitonin cells, and (5) the thyroid gland displays unusual follicles of two categories, (a) follicles with ciliated epithelial cells and (b) follicles with squamous epithelium.