Search

Talpid moles (Talpidae, Eulipotyphla) are mammals highly specialised in burrowing using their forelimbs. Fossoriality has allowed moles to expand their ecological niche by enabling access to subterranean resources and spaces. This specialisation in burrowing has led to adaptations in the forelimb bones of moles for humeral rotation digging, a distinctive strategy unparalleled among other diggers. While bone robustness has been examined in moles through external morphology, the adaptation of bone microstructure to digging strategy remains unclear. Based on two assumptions, (1) the humerus of moles is subjected to a torsional load due to humeral rotation digging, and (2) the magnitude of torsional load correlates with the compactness of the substrate in which the individuals can dig, we hypothesised that humeral rotation digging influences bone microstructure. Comparative analyses of transverse sections from the humeri and femora of three mole species (Mogera imaizumii, Mogera wogura and Urotrichus talpoides; Talpidae) and an outgroup eulipotyphlan (Suncus murinus; Soricidae) revealed that (1) vascular canals distributed in the humeri of moles align more predominantly circumferential along the bone walls, indicating an adaptation to the torsion generated by humeral rotation digging, and (2) the laminarity of vascular canals, particularly in Mogera species compared with Urotrichus, potentially reflects differences in the magnitude of load due to substrate compactness during digging. The aligned vascular canals are distinctive traits not observed in mammals employing other digging strategies. This suggests that vascular canal laminarity can be an indicator of not only humeral rotation digging in fossorial animals, but also the variation of eco-spaces in talpid species., (© 2024 Anatomical Society.)

The forelimb is involved in many behaviours including locomotion. Notably, the humero-ulnar articulation, implicated in the elbow joint, is of particular importance for both mobility and stability. Functional constraints, induced in part by environmental plasticity, are thought to drive an important part of the bone shape as bone directly responds and remodels in response to both muscle and external forces. In this context, the study of subterranean moles is of particular interest. These moles occupy a hard and heavy medium in comparison with air or water, requiring a powerful body structure to shear and shift the soil. Their general morphology is therefore adapted to digging and to their subterranean lifestyle. The various morpho-functional patterns, which drive diverse abilities according to the environment, are likely targets of natural selection and it is, therefore, useful to understand the relationships between the bone shape and their function. Here, we quantify, through 3D geometric morphometric methods, the interspecific variability in the morphology of the ulna and humerus of three Talpa species, including the new species Talpa aquitania, to infer their potential consequence in species digging performance. We also quantify shape covariation and morphological integration between the humerus and the ulna to test whether these bones evolve as a uniform functional unit or as more or less independent modules. Our results show that interspecific anatomical differences in the humerus and ulna exist among the three species. Shape changes are mostly located at the level of joints and muscle attachments. As the species tend to live in allopatry and the fossorial lifestyle induces strong ecological constraints, interspecific variations could be explained by the properties of the environment in which they live, such as the compactness of the soil. Our results also show that the humerus and ulna are highly integrated. The covariation between the humerus and ulna in moles is dominated by variation in the attachment areas and particularly of the attachment areas of shoulder muscles concerning the humerus, which affect the mechanical force deployed during locomotion and digging. This study also highlights that in the new species, T. aquitania, variations in anatomical structure (general shape and joints) exist and are related to the locality of collect of the individuals., (© 2022 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.)

The evolution of complex morphological structures can be characterized by the interplay between different anatomical regions evolving under functional integration in response to shared selective pressures. Using the highly derived humeral morphology of talpid moles as a model, here we test whether functional performance is linked to increased levels of evolutionary integration between humerus subunits and, if so, what the strength is of the relationship. Combining two-dimensional geometric morphometrics, phylogenetic comparative methods, and functional landscape modeling, we demonstrate that the high biomechanical performance of subterranean moles' humeri is coupled with elevated levels of integration, whereas taxa with low-performance values show intermediate or low integration. Theoretical morphs occurring in high-performance areas of the functional landscape are not occupied by any species, and show a marked drop in covariation levels, suggesting the existence of a strong relationship between integration and performance in the evolution of talpid moles' humeri. We argue that the relative temporal invariance of the subterranean environment may have contributed to stabilize humeral morphology, trapping subterranean moles in a narrow region of the landscape and impeding any attempt to reposition on a new ascending slope., (© 2022 The Authors. Evolution published by Wiley Periodicals LLC on behalf of The Society for the Study of Evolution.)

Object recognition is among the basic survival skills of human beings and other animals. To date, artificial intelligence (AI) assisted high-performance object recognition is primarily visual-based, empowered by the rapid development of sensing and computational capabilities. Here, we report a tactile-olfactory sensing array, which was inspired by the natural sense-fusion system of star-nose mole, and can permit real-time acquisition of the local topography, stiffness, and odor of a variety of objects without visual input. The tactile-olfactory information is processed by a bioinspired olfactory-tactile associated machine-learning algorithm, essentially mimicking the biological fusion procedures in the neural system of the star-nose mole. Aiming to achieve human identification during rescue missions in challenging environments such as dark or buried scenarios, our tactile-olfactory intelligent sensing system could classify 11 typical objects with an accuracy of 96.9% in a simulated rescue scenario at a fire department test site. The tactile-olfactory bionic sensing system required no visual input and showed superior tolerance to environmental interference, highlighting its great potential for robust object recognition in difficult environments where other methods fall short., (© 2022. The Author(s).)

Here I review, compare, and contrast the neurobiology and behavior of the common, eastern mole (Scalopus aquaticus) and the star-nosed mole (Condylura cristata). These two species are part of the same family (Talpidae) and have similar body size and general morphology. But they differ in sensory specializations, complexity of neocortical organization, and behavior. The star-nosed mole has an elaborate mechanosensory organ-the star-consisting of 22 epidermal appendages (rays) covered with 25,000 touch domes called Eimer's organs. This densely innervated structure is represented in the neocortex in three different somatosensory maps, each visible in flattened neocortical sections as a series of 11 modules representing the 11 rays from the contralateral body. The 11th ray is greatly magnified in primary somatosensory cortex (S1). Behavioral studies show the star is moved in a saccadic manner and the 11th ray is a high-resolution tactile fovea, allowing star-nosed moles to forage on small prey with unprecedented speed and efficiency. In contrast, common mole noses lack Eimer's organs, their neocortex contains only two cortical maps of the nose, and they cannot localize small prey. Yet common moles have exceptional olfactory abilities, sniffing in stereo to rapidly localize discrete odor sources originating from larger prey. In addition, common moles are shown to track odorant trails laid down by moving prey. These results highlight the surprising abilities of species once thought to be simple, and the usefulness of diverse species in revealing general principles of brain organization and behavior. Anat Rec, 2019. © 2019 American Association for Anatomy., (© 2019 American Association for Anatomy.)

Background: Understanding the mechanisms promoting or constraining morphological diversification within clades is a central topic in evolutionary biology. Ecological transitions are of particular interest because of their influence upon the selective forces and factors involved in phenotypic evolution. Here we focused on the humerus and mandibles of talpid moles to test whether the transition to the subterranean lifestyle impacted morphological disparity and phenotypic traits covariation between these two structures., Results: Our results indicate non-subterranean species occupy a significantly larger portion of the talpid moles morphospace. However, there is no difference between subterranean and non-subterranean moles in terms of the strength and direction of phenotypic integration., Conclusions: Our study shows that the transition to a subterranean lifestyle significantly reduced morphological variability in talpid moles. However, this reduced disparity was not accompanied by changes in the pattern of traits covariation between the humerus and the mandible, suggesting the presence of strong phylogenetic conservatism within this pattern.

Many people are familiar with the meandering tunnels of moles, far fewer are familiar with the creatures that made them. Such secrecy is, of course, one of the great benefits of burrowing through the earth where few predators can follow. But it's not the only benefit. Soil contains a smorgasbord of nutritious invertebrate prey - hence all the tunneling. In fact the richness of the soil niche has given rise to a diversity of mole species that could be said to resemble the evolutionary diversification of bats, though on a smaller scale. In both cases, mammals have evolved a suite of unique anatomical traits (coincidentally involving modification of the forelimb) that allows them to exploit a huge resource of invertebrate prey that is largely inaccessible to their competitors. For bats the thin, delicate wings were the key innovation, for moles the forelimbs have undergone a similarly dramatic structural shift, but in the opposite direction - the bones have become short, stout, and powerful to act as shovels., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Moles are a strictly fossorial Soricomorpha species and possess a suite of specialized adaptations to subterranean life. However, the contractile function of skeletal muscles in moles remains unclear. We compared muscle fiber-type distribution in two mole species (the large Japanese mole and lesser Japanese mole) with that in four other Soricomorpha species that are semi-fossorial, terrestrial, or semi-aquatic (the Japanese shrew-mole, house shrew, Japanese white-toothed shrew, and Japanese water shrew). For a single species, the fiber-type distribution in up to 38 muscles was assessed using immunohistochemical staining and/or gel electrophoresis. We found that slow and fatigue-resistant Type I fibers were absent in almost all muscles of all species studied. Although, the two methods of determining the fiber type did not give identical results, they both revealed that fast Type IIb fibers were absent in mole muscles. The fiber-type distribution was similar among different anatomical regions in the moles. This study demonstrated that the skeletal muscles of moles have a homogenous fiber-type distribution compared with that in Soricomorpha species that are not strictly fossorial. Mole muscles are composed of Type IIa fibers alone or a combination of Type IIa and relatively fast Type IIx fibers. The homogenous fiber-type distribution in mole muscles may be an adaptation to structurally simple subterranean environments, where there is no need to support body weight with the limbs, or to move at high speeds to pursue prey or to escape from predators. Anat Rec, 302:1010-1023, 2019. © 2018 Wiley Periodicals, Inc., (© 2018 Wiley Periodicals, Inc.)

Many living species of golden moles (Chrysochloridae) have greatly enlarged middle ear ossicles, believed to be used in the detection of ground vibrations through inertial bone conduction. Other unusual features of chrysochlorids include internally coupled middle ear cavities and the loss of the tensor tympani muscle. Our understanding of the evolutionary history of these characteristics has been limited by the paucity of fossil evidence. In this article, we describe for the first time the exquisitely preserved middle and inner ears of Namachloris arenatans from the Palaeogene of Namibia, visualised using computed tomography, as well as ossicles attributed to this species. We compare the auditory region of this fossil golden mole, which evidently did not possess a hypertrophied malleus, to those of three extant species with similarly sized ear ossicles, Amblysomus hottentotus, Calcochloris obtusirostris, and Huetia leucorhinus. The auditory region of Namachloris shares many common features with the living species, including a pneumatized, trabeculated basicranium and lateral skull wall, arteries and nerves of the middle ear contained in bony tubes, a highly coiled cochlea, a secondary crus commune, and no identifiable canaliculus cochleae for the perilymphatic duct. However, Namachloris differs from extant golden moles in the apparent absence of a basicranial intercommunication between the right and left ears, the possession of a tensor tympani muscle and aspects of ossicular morphology. One Namachloris skull showed what may be pneumatization of some of the dorsal cranial bones, extending right around the brain. Although the ossicles are small in absolute terms, one of the Huetia leucorhinus specimens had a more prominent malleus head than the other. This potentially represents a previously unrecognised subspecific difference., (© 2017 Wiley Periodicals, Inc.)

The penile and clitoral anatomy of four species of Talpid moles (broad-footed, star-nosed, hairy-tailed, and Japanese shrew moles) were investigated to define penile and clitoral anatomy and to examine the relationship of the clitoral anatomy with the presence or absence of ovotestes. The ovotestis contains ovarian tissue and glandular tissue resembling fetal testicular tissue and can produce androgens. The ovotestis is present in star-nosed and hairy-tailed moles, but not in broad-footed and Japanese shrew moles. Using histology, three-dimensional reconstruction, and morphometric analysis, sexual dimorphism was examined with regard to a nine feature masculine trait score that included perineal appendage length (prepuce), anogenital distance, and presence/absence of bone. The presence/absence of ovotestes was discordant in all four mole species for sex differentiation features. For many sex differentiation features, discordance with ovotestes was observed in at least one mole species. The degree of concordance with ovotestes was highest for hairy-tailed moles and lowest for broad-footed moles. In relationship to phylogenetic clade, sex differentiation features also did not correlate with the similarity/divergence of the features and presence/absence of ovotestes. Hairy-tailed and Japanese shrew moles reside in separated clades, but they exhibit a high degree of congruence. Broad-footed and hairy-tailed moles reside within the same clade but had one of the lowest correlations in features and presence/absence of ovotestes. Thus, phylogenetic affinity and the presence/absence of ovotestes are poor predictors for most sex differentiation features within mole external genitalia., (© 2017 Wiley Periodicals, Inc.)

Fossorial talpid moles use their limbs predominantly for digging, which explains their highly specialized anatomy. The humerus is particularly short and dorsoventrally rotated, with broadened distal and proximal parts where muscles attach and which facilitate powerful abductive movements. The radius and ulna are exceptionally robust and short. The ulna has an expanded olecranon process. The femur is generalized, but the fused tibia-fibula complex is short and robust. To understand the developmental bases of these specializations, we studied expression patterns of four 5' Hox genes in the fossorial Iberian mole (Talpa occidentalis). These genes are known to play major roles in patterning the developing limb skeleton in the mouse, with which comparisons were made (Mus musculus, C57BL/6Jico strain). We find that HoxA9 expression is spatially expanded in the developing stylopodial area in the mole forelimb, compared to the less specialized mouse forelimb and mole hind limb. HoxD9 expression does not extend into the thoracic body wall in the mole forelimb in contrast to the mouse, and is also reduced in the presumptive zeugopodium in mole forelimb, compared to mouse. Expression of HoxD11 is upregulated in the mole in the postaxial area of the hind limb zeugopod, compared to the mouse. On the other hand, HoxD13 is downregulated in the postaxial zeugopodial area in the forelimb of the mole, compared to the mouse. The differences in the expression patterns of these 5' Hox genes between Talpa and Mus are an indication of the developmental changes going hand in hand with anatomical digging adaptations in the mole adult., (© 2016 Wiley Periodicals, Inc.)

It is generally held that the right and left middle ears of mammals are acoustically isolated from each other, such that mammals must rely on neural computation to derive sound localisation cues. There are, however, some unusual species in which the middle ear cavities intercommunicate, in which case each ear might be able to act as a pressure-difference receiver. This could improve sound localisation at lower frequencies. The platypus Ornithorhynchus is apparently unique among mammals in that its tympanic cavities are widely open to the pharynx, a morphology resembling that of some non-mammalian tetrapods. The right and left middle ear cavities of certain talpid and golden moles are connected through air passages within the basicranium; one experimental study on Talpa has shown that the middle ears are indeed acoustically coupled by these means. Having a basisphenoid component to the middle ear cavity walls could be an important prerequisite for the development of this form of interaural communication. Little is known about the hearing abilities of platypus, talpid and golden moles, but their audition may well be limited to relatively low frequencies. If so, these mammals could, in principle, benefit from the sound localisation cues available to them through internally coupled ears. Whether or not they actually do remains to be established experimentally.

Quantifying somatosensory receptor distribution in glabrous skin is usually difficult because of the diversity of skin receptor subtypes and their location within the dermis and epidermis. However, the glabrous noses of moles are an exception. In most species of moles, the skin on the nose is covered with domed mechanosensory units known as an Eimer's organs. Eimer's organs contain a stereotyped array of different mechanosensory neurons, meaning that the distribution of mechanosensitive nerve endings can be inferred by visual inspection of the skin surface. Here we detail the distribution of Eimer's organs on the highly derived somatosensory star on the rostrum of the star-nosed mole (Condylura cristata). The star consists of 22 fleshy appendages, or rays, that are covered in Eimer's organs. We find that the density of Eimer's organs increases from proximal to distal locations along the length of the star's rays with a ratio of 1:2.3:3.1 from the surface nearest to the nostril, to the middle part of ray, to the ray tip, respectively. This ratio is comparable to the increase in receptor unit density reported for the human hand, from the palm, to the middle of the digits, to the distal fingertips. We also note that the tactile fovea of the star-nosed mole, located on the medial ventral ray, does not have increased sensory organ density, and we describe these findings in comparison with other sensory fovea., (© 2015 Wiley Periodicals, Inc.)

Anatomy of male and female external genitalia of adult mice (Mus musculus) and broad-footed moles (Scapanus latimanus) was re-examined to provide more meaningful anatomical terminology. In the past the perineal appendage of male broad-footed moles has been called the penis, while the female perineal appendage has been given several terms (e.g. clitoris, penile clitoris, peniform clitoris and others). Histological examination demonstrates that perineal appendages of male and female broad-footed moles are the prepuce, which in both sexes are covered externally with a hair-bearing epidermis and lacks erectile bodies. The inner preputial epithelium is non-hair-bearing and defines the preputial space in both sexes. The penis of broad-footed moles lies deep within the preputial space, is an "internal organ" in the resting state and contains the penile urethra, os penis, and erectile bodies. The clitoris of broad-footed moles is defined by a U-shaped clitoral epithelial lamina. Residing within clitoral stroma encompassed by the clitoral epithelial lamina is the corpus cavernosum, blood-filled spaces and the urethra. External genitalia of male and female mice are anatomically similar to that of broad-footed moles with the exception that in female mice the clitoris contains a small os clitoridis and lacks defined erectile bodies, while male mice have an os penis and a prominent distal cartilaginous structure within the male urogenital mating protuberance (MUMP). Clitori of female broad-footed moles lack an os clitoridis but contain defined erectile bodies, while male moles have an os penis similar to the mouse but lack the distal cartilaginous structure., (© 2015 Wiley Periodicals, Inc.)

The enigmatic Early Miocene fossorial mammal Mesoscalops montanensis shows one of the most modified humeri among terrestrial mammals. It has been suggested, on qualitative considerations, that this species has no extant homologues for humerus kinematics and that, functionally, the closest extant group is represented by Chrysochloridae. We combine here three dimensional geometric morphometrics, finite element analysis and phylogenetic comparative methods to explore the shape and mechanical stress states of Mesoscalops montanensis as well as of extant and extinct Talpidae and Chrysochloridae under realistic digging simulations. Evolutionary convergence analyses reveal that the shape of Mesoscalops montanensis represents a unique morphology in the context of fossorial mammals and that its functional performance, albeit superficially similar to that of extant Chrysochloridae, still represents a nonconvergent optimum for adaptation to digging., (© 2015 Wiley Periodicals, Inc.)

We investigated if and how the inner ear region undergoes similar adaptations in small, fossorial, insectivoran-grade mammals, and found a variety of inner ear phenotypes. In our sample, afrotherian moles (Chrysochloridae) and the marsupial Notoryctes differ from most other burrowing mammals in their relatively short radii of semicircular canal curvature; chrysochlorids and fossorial talpids share a relatively long interampullar width. Chrysochlorids are unique in showing a highly coiled cochlea with nearly four turns. Extensive cochlear coiling may reflect their greater ecological dependence on low frequency auditory cues compared to talpids, tenrecids, and the marsupial Notoryctes. Correspondingly, the lack of such extensive coiling in the inner ear of other fossorial species may indicate a greater reliance on other senses to enable their fossorial lifestyle, such as tactile sensation from vibrissae and Eimer's organs. The reliance of chrysochlorids on sound is evident in the high degree of coiling and in the diversity of its mallear types, and may help explain the lack of any semiaquatic members of that group. The simplest mallear types among chrysochlorids are not present in the basal-most members of that clade, but all extant chrysochlorids investigated to date exhibit extensive cochlear coiling. The chrysochlorid ear region thus exhibits mosaic evolution; our data suggest that extensive coiling evolved in chrysochlorids prior to and independently of diversification in middle ear ossicle size and shape., (© 2015 Wiley Periodicals, Inc.)

The adult mammalian cerebellum is histologically uniform. However, concealed beneath the simple laminar architecture, it is organized rostrocaudally and mediolaterally into complex arrays of transverse zones and parasagittal stripes that is both highly reproducible between individuals and generally conserved across mammals and birds. Beyond this conservation, the general architecture appears to be adapted to the animal's way of life. To test this hypothesis, we have examined cerebellar compartmentation in the talpid star-nosed mole Condylura cristata. The star-nosed mole leads a subterranean life. It is largely blind and instead uses an array of fleshy appendages (the "star") to navigate and locate its prey. The hypothesis suggests that cerebellar architecture would be modified to reduce regions receiving visual input and expand those that receive trigeminal afferents from the star. Zebrin II and phospholipase Cß4 (PLCß4) immunocytochemistry was used to map the zone-and-stripe architecture of the cerebellum of the adult star-nosed mole. The general zone-and-stripe architecture characteristic of all mammals is present in the star-nosed mole. In the vermis, the four typical transverse zones are present, two with alternating zebrin II/PLCß4 stripes, two wholly zebrin II+/PLCß4-. However, the central and nodular zones (prominent visual receiving areas) are proportionally reduced in size and conversely, the trigeminal-receiving areas (the posterior zone of the vermis and crus I/II of the hemispheres) are uncharacteristically large. We therefore conclude that cerebellar architecture is generally conserved across the Mammalia but adapted to the specific lifestyle of the species.

Somatosensory inputs from the face project to multiple regions of the trigeminal nuclear complex in the brainstem. In mice and rats, three subdivisions contain visible representations of the mystacial vibrissae, the principal sensory nucleus, spinal trigeminal subnucleus interpolaris, and subnucleus caudalis. These regions are considered important for touch with high spatial acuity, active touch, and pain and temperature sensation, respectively. Like mice and rats, the star-nosed mole (Condylura cristata) is a somatosensory specialist. Given the visible star pattern in preparations of the star-nosed mole cortex and the principal sensory nucleus, we hypothesized there were star patterns in the spinal trigeminal nucleus subnuclei interpolaris and caudalis. In sections processed for cytochrome oxidase, we found star-like segmentation consisting of lightly stained septa separating darkly stained patches in subnucleus interpolaris (juvenile tissue) and subnucleus caudalis (juvenile and adult tissue). Subnucleus caudalis represented the face in a three-dimensional map, with the most anterior part of the face represented more rostrally than posterior parts of the face. Multiunit electrophysiological mapping was used to map the ipsilateral face. Ray-specific receptive fields in adults matched the CO segmentation. The mean areas of multiunit receptive fields in subnucleus interpolaris and caudalis were larger than previously mapped receptive fields in the mole's principal sensory nucleus. The proportion of tissue devoted to each ray's representation differed between the subnucleus interpolaris and the principal sensory nucleus. Our finding that different trigeminal brainstem maps can exaggerate different parts of the face could provide new insights for the roles of these different somatosensory stations., (© 2014 Wiley Periodicals, Inc.)

Placentation determines the developmental status of the neonate, which can be considered as the most vulnerable stage in the mammalian life cycle. In this respect, the different evolutionary and ecological adaptations of marsupial and placental mammals have most likely been associated with the different reproductive strategies of the two therian clades. The morphotypes of marsupial and placental neonates, as well as the placental stem species pattern of Marsupialia, have already been reconstructed. To contribute to a better understanding of the evolution of Placentalia, a histological and ultrastructural investigation of the placenta in three representatives of Eulipotyphla, that is, core insectivores, has been carried out in this study. We studied the Musk shrew (Suncus murinus), the four-toed hedgehog (Atelerix albiventris), and the Iberian mole (Talpa occidentalis). As a result, a eulipotyphlan placental morphotype consisting of a compact and invasive placenta was reconstructed. This supports the widely accepted hypothesis that the stem lineage of Placentalia is characterized by an invasive, either endothelio- or hemochorial placenta. Evolutionary transformations toward a diffuse, noninvasive placenta occurred in the stem lineages of lower primates and cetartiodactyles and were associated with prolonged gestation and the production of few and highly precocial neonates. Compared to the choriovitelline placenta of Marsupialia, the chorioallantoic placenta of Placentalia allows for a more intimate contact and is associated with more advanced neonates., (© 2014 Wiley Periodicals, Inc.)

Small-eared shrews (Mammalia: Soricidae: Cryptotis), exhibit modifications of the forelimb skeleton that have been interpreted as adaptations for semifossoriality. Most species inhabit remote regions, however, and their locomotory and foraging behaviors remain mostly speculative. To better understand the morphological modifications in the absence of direct observations, we quantified variation in these species by measuring 151 individuals representing 18 species and populations of Cryptotis and two species of moles (Talpidae) for comparison. From our measurements, we calculated 22 indices, most of which have been used previously to characterize substrate use among rodents and other taxa. We analyzed the indices using 1) average percentile ranks, 2) principal components analysis, and 3) cluster analysis. From these analyses, we determined that three basic modes of substrate adaptation are present within Cryptotis: 1) a primarily terrestrial mode, with species that are capable of burrowing, but lack adaptations to increase digging efficiency, 2) a semifossorial mode, with species whose forelimbs bones show strong muscle attachment areas and increased mechanical advantage, and 3) an intermediate mode. In addition to identifying new morphological characters and contributing to our understanding of the functional morphology of soricids, these analyses provide additional insight into the ecology of the species of interest., (© 2014 Wiley Periodicals, Inc.)

Adult neurogenesis in the mammalian brain is now a widely accepted phenomenon, typically occurring in two forebrain structures: the subgranular zone (SGZ) of the hippocampal dentate gyrus and the subventricular zone (SVZ). Until recently, the majority of studies have focused on laboratory rodents, and it is under debate whether the process of adult neurogenesis occurs outside of the SGZ and the SVZ in other mammalian species. In the present study, we investigated potential adult neurogenetic sites in the brains of two elephant shrews/sengis, a golden mole and a rock hyrax, all members of the superorder Afrotheria. Doublecortin (DCX) immunoreactivity was used as a proxy to visualise adult neurogenesis, which is expressed in neuronal precursor cells and immature neurons. In all four species, densely packed DCX-positive cells were present in the SVZ, from where cells appear to migrate along the rostral migratory stream towards the olfactory bulb (OB). DCX-immunopositive cells were present in the granular cell layer and the glomerular layer of the OB. In the hippocampus, DCX-immunopositive cells were observed in the SGZ and in the granular layer of the dentate gyrus, with DCX-immunopositive processes extending into the molecular layer. In addition to these well-established adult neurogenic regions, DCX-immunopositive cells were also observed in layer II of the neocortex and the piriform cortex. While the present study reveals a similar pattern of adult neurogenesis to that reported previously in other mammals, further studies are needed to clarify if the cortical DCX-immunopositive cells are newly generated neurons or cells undergoing cortical remodelling., (© 2014 S. Karger AG, Basel.)

Moles have modified thoracic limbs with hypertrophied pectoral girdle muscles that allow them to apply remarkably high lateral out-forces during the power stroke when burrowing. To further understand the high force capabilities of mole forelimbs, architectural properties of the thoracic limb muscles were quantified in the Eastern mole (Scalopus aquaticus). Architectural properties measured included muscle mass, moment arm, belly length, fascicle length, and pennation angle, and these were used to provide estimates of maximum isometric force, joint torque, and power. Measurements of muscle moment arms and limb lever lengths were additionally used to analyze the out-force contributions of the major pectoral girdle muscles. Most muscles have relatively long fascicles and little-to-no pennation. The humeral abductor/rotators as a functional group are massive and are capable of relatively high force, power, and joint torque. Of this group, the bipennate m. teres major is the most massive and has the capacity to produce the highest force and joint torque to abduct and axially rotate the humerus. In general, the distal limb muscles are relatively small, but have the capacity for high force and mechanical work by fascicle shortening. The muscle architectural properties of the elbow extensors (e.g., m. triceps brachii) and carpal flexors (e.g., m. palmaris longus) are consistent with the function of these muscles to augment lateral out-force application. The humeral abductor/rotators m. latissimus dorsi, m. teres major, m. pectoralis, and m. subscapularis are calculated to contribute 13.9 N to out-force during the power stroke, and this force is applied in a 'frontal' plane causing abduction of the humerus about the sternoclavicular joint. Moles have several specializations of their digging apparatus that greatly enhance the application of out-force, and these morphological features suggest convergence on limb form and burrowing function between New and Old World moles., (Copyright © 2013 Wiley Periodicals, Inc.)

The distribution of mucous secreting goblet cells was examined in the gastrointestinal tracts of three insectivores namely: Acomys spinosissimus (Southern African spiny mouse), Crocidura cyanea (Reddish gray musk shrew) and Amblysomus hottentotus (Hottentot golden mole) in order to improve our understanding of the quality and composition of the protective intestinal biofilm. Intestinal tracts were fixed and processed to wax for histology. Serial transverse sections were stained using alcian blue-periodic acid Schiff, alcian blue-aldehyde fuchsin and alcian blue-high iron diamine techniques. Photomicrographs of the stained sections were analyzed by quantifying the number of goblet cells containing mucins per mm(2) in the surface epithelial or crypt areas. Neutral mucins predominated in the gastric epithelium of all three insectivores, while sialomucins were absent in the stomach of C. cyanea. In all three species, goblet cells producing a mixture of neutral and acid mucins were most abundant throughout the intestinal tract as were cells secreting a mixture of sulfomucins and sialomucins. However, differences between the insectivore species were observed in the qualitative expression and distribution of mucins throughout the intestinal tract. Similarities between the insectivores of this study and other distantly related species suggest that mixed mucin goblet cells are essential for the formation of the biofilm, irrespective of their diet or taxonomy., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

The gastrointestinal morphology was investigated in three mammalian insectivorous species, namely Acomys spinosissimus, Crocidura cyanea, and Amblysomus hottentotus. The aim of the study was to provide a comprehensive morphological comparison between the different species and to explore whether anatomical gastrointestinal adaptations are associated with the insectivorous diet of these species. The shape, proportional length, and proportional surface areas of the different gastrointestinal regions were recorded and compared in the three insectivores. Hematoxylin and Eosin (H&E) and Alcian Blue/Periodic Acid Schiff (AB/PAS) were used for morphological assessment. In all three species, the stomach was simple and uncompartmentalized. The internal aspect of the stomach in A. spinosissimus was hemi-glandular, containing stratified squamous epithelium in the fundus, with glandular epithelium in the body and pyloric region. However, C. cyanea and A. hottentotus had wholly glandular stomachs. Paneth cells were not observed in the intestinal tracts of C. cyanea and A. hottentotus. Acomys spinosissimus was the only species studied that had a cecum. The proximal colonic region of A. spinosissimus had V-shaped mucosal folds. Histologically, C. cyanea had villi throughout the entire gastrointestinal tract (GIT), whereas for A. hottentotus villi were not present in the most distal gastrointestinal regions. In both C. cyanea and A. hottentotus, longitudinal mucosal folds were present in the distal part of the colon. The GITs of C. cyanea and A. hottentotus showed little morphological differentiation namely, a simple, glandular stomach and the lack of a cecum., (Copyright © 2013 Wiley Periodicals, Inc.)

The present study describes the organisation of the cholinergic, catecholaminergic, and serotonergic neurons in the brains of the giant otter shrew, the Hottentot golden mole and the four-toed sengi, and the orexinergic (hypocretinergic) system in the giant otter shrew and four-toed sengi. The aim of the present study was to investigate the possible differences in the nuclear complement of these neural systems in comparison to previous studies on other Afrotherian species and mammalian species in general. Brains of the golden mole, sengi and giant otter shrew were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyl-transferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei revealed in the current study were similar among the species investigated, to other Afrotherian species, and to mammals generally, but certain differences in the nuclear complement highlighted phylogenetic interrelationships. The golden mole was observed to have cholinergic interneurons in the cerebral cortex, hippocampus, olfactory bulb and amygdala. The four-toed sengi had cholinergic neurons in both colliculi and in the cochlear nucleus, but lacked the catecholaminergic A15d group in the hypothalamus. In both the golden mole and the four-toed sengi, the locus coeruleus (A6d group) was made up of few neurons. The golden mole also exhibited an unusual foreshortening of the brain, such that a major (mesencephalic?) flexure in the brainstem was evident., (Copyright © 2013 Elsevier B.V. All rights reserved.)

In males of seasonally breeding species, testes undergo a severe involution at the end of the breeding season, with a major volume decrease due to massive germ-cell depletion associated with photoperiod-dependent reduced levels of testosterone and gonadotropins. Although it has been repeatedly suggested that apoptosis is the principal effector of testicular regression in vertebrates, recent studies do not support this hypothesis in some mammals. The purpose of our work is to discover alternative mechanisms of testis regression in these species. In this paper, we have performed a morphological, hormonal, ultrastructural, molecular, and functional study of the mechanism of testicular regression and the role that cell junctions play in the cell-content dynamics of the testis of the Iberian mole, Talpa occidentalis, throughout the seasonal breeding cycle. Desquamation of live, nonapoptotic germ cells has been identified here as a new mechanism for seasonal testis involution in mammals, indicating that testis regression is regulated by modulating the expression and distribution of the cell-adhesion molecules in the seminiferous epithelium. During this process, which is mediated by low intratesticular testosterone levels, Sertoli cells lose their nursing and supporting function, as well as the impermeability of the blood-testis barrier. Our results contradict the current paradigm that apoptosis is the major testis regression effector in vertebrates, as it is clearly not true in all mammals. The new testis regression mechanism described here for the mole could then be generalized to other mammalian species. Available data from some previously studied mammals should be reevaluated.

Background: Talpids include forms with different degree of fossoriality, with major specializations in the humerus in the case of the fully fossorial moles. We studied the humeral microanatomy of eleven extant and eight extinct talpid taxa of different lifestyles and of two non-fossorial outgroups and examined the effects of size and phylogeny. We tested the hypothesis that bone microanatomy is different in highly derived humeri of fossorial taxa than in terrestrial and semi-aquatic ones, likely due to special mechanical strains to which they are exposed to during digging. This study is the first comprehensive examination of histological parameters in an ecologically diverse and small-sized mammalian clade., Results: No pattern of global bone compactness was found in the humeri of talpids that could be related to biomechanical specialization, phylogeny or size. The transition zone from the medullary cavity to the cortical compacta was larger and the ellipse ratio smaller in fossorial talpids than in non-fossorial talpids. No differences were detected between the two distantly related fossorial clades, Talpini and Scalopini., Conclusions: At this small size, the overall morphology of the humerus plays a predominant role in absorbing the load, and microanatomical features such as an increase in bone compactness are less important, perhaps due to insufficient gravitational effects. The ellipse ratio of bone compactness shows relatively high intraspecific variation, and therefore predictions from this ratio based on single specimens are invalid.

The semicircular canals (SCs), part of the vestibular apparatus of the inner ear, are directly involved in the detection of angular motion of the head for maintaining balance, and exhibit adaptive patterns for locomotor behaviour. Consequently, they are generally believed to show low levels of intraspecific morphological variation, but few studies have investigated this assumption. On the basis of high-resolution computed tomography, we present here, to our knowledge, the first comprehensive study of the pattern of variation of the inner ear with a focus on Xenarthra. Our study demonstrates that extant three-toed sloths show a high level of morphological variation of the bony labyrinth of the inner ear. Especially, the variation in shape, relative size and angles of their SCs greatly differ from those of other, faster-moving taxa within Xenarthra and Placentalia in general. The unique pattern of variation in three-toed sloths suggests that a release of selection and/or constraints on their organ of balance is associated with the observed wide range of phenotypes. This release is coincident with their slow and infrequent locomotion and may be related, among other possible factors, to a reduced functional demand for a precise sensitivity to movement.

This study provides a contribution to the reconstruction of the eulipotyphlan placental morphotype and also may help resolving a long-standing conflict about the interhaemal barrier in moles. As detailed descriptions of talpid placentation, only available for Talpa europaea and Scalopus aquaticus, led to a controversial debate on the nature of interhaemal barrier, the collection of more placental data of further mole species was strongly desired. Hence, the placentas of six gestational stages of Talpa occidentalis have been studied concerning their morphogenesis and ultrastructure with special focus on the structure of the interhaemal barrier and heterophagous regions. Generally, the mode of placentation in T. occidentalis resembles that of T. europaea, including a broad, discoid, antimesometrial, definitive chorioallantoic placenta of labyrinthine type being still villous in earlier stages. Within the labyrinth, the zona intima shows an endotheliochorial interhaemal barrier with a two-layered trophoblast. This clearly contradicts former statements on the S. aquaticus placenta made by Prasad et al. (1979), although their findings cannot exclude a totally different interpretation. Regardless, the placenta of moles represents the least invasive mode of placentation among Eulipotyphla, which otherwise have highly invasive placentas. Although the phagocytic areolas situated above uterine gland openings are heterophagous, they mainly seem to serve fetal histiotrophic nutrition, at least early in pregnancy. In later stages the number of glands and areolas decreases. This special type of additional phagocytic region is usually most common in species with noninvasive, epitheliochorial placentation, which suggests a correlation between placental invasiveness and the occurrence and type of phagocytic placental structures. The compact and invasive mode of placentation of Talpidae and all other Eulipotyphla seems to be plesiomorphic within Laurasiatheria and is always correlated with an altricial neonate., (© 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.)

The shape and mechanical performance in Talpidae humeri were studied by means of Geometric Morphometrics and Finite Element Analysis, including both extinct and extant taxa. The aim of this study was to test whether the ability to dig, quantified by humerus mechanical performance, was characterized by convergent or parallel adaptations in different clades of complex tunnel digger within Talpidae, that is, Talpinae+Condylura (monophyletic) and some complex tunnel diggers not belonging to this clade. Our results suggest that the pattern underlying Talpidae humerus evolution is evolutionary parallelism. However, this insight changed to true convergence when we tested an alternative phylogeny based on molecular data, with Condylura moved to a more basal phylogenetic position. Shape and performance analyses, as well as specific comparative methods, provided strong evidence that the ability to dig complex tunnels reached a functional optimum in distantly related taxa. This was also confirmed by the lower phenotypic variance in complex tunnel digger taxa, compared to non-complex tunnel diggers. Evolutionary rates of phenotypic change showed a smooth deceleration in correspondence with the most recent common ancestor of the Talpinae+Condylura clade., (Copyright © 2012 Wiley Periodicals, Inc.)

Talpid moles across all northern continents exhibit a remarkably large, sickle-like radial sesamoid bone anterior to their five digits, always coupled with a smaller tibial sesamoid bone. A possible developmental mechanism behind this phenomenon was revealed using molecular markers during limb development in the Iberian mole (Talpa occidentalis) and a shrew (Cryptotis parva), as shrews represent the closest relatives of moles but do not show these conspicuous elements. The mole's radial sesamoid develops later than true digits, as shown by Sox9, and extends into the digit area, developing in relation to an Msx2-domain at the anterior border of the digital plate. Fgf8 expression, marking the apical ectodermal ridge, is comparable in both species. Developmental peculiarities facilitated the inclusion of the mole's radial sesamoid into the digit series; talpid moles circumvent the almost universal pentadactyly constraint by recruiting wrist sesamoids into their digital region using a novel developmental pathway and timing.

Star-nosed moles are somatosensory specialists that explore their environment with 22 appendages that ring their nostrils. The appendages are covered with sensory domes called Eimer's organs. Each organ is associated with a Merkel cell-neurite complex, a lamellated corpuscle, and a series of 5-10 free nerve endings that form a circle of terminal swellings. Anatomy and electrophysiological recordings suggest that Eimer's organs detect small shapes and textures. There are parallels between the organization of the mole's somatosensory system and visual systems of other mammals. The centre of the star is a tactile fovea used for detailed exploration of objects and prey items. The tactile fovea is over-represented in the neocortex, and this is evident in the modular, anatomically visible representation of the star. Multiple maps of the star are visible in flattened cortical preparations processed for cytochrome oxidase or NADPH-diaphorase. Star-nosed moles are the fastest known foragers among mammals, able to identify and consume a small prey item in 120 ms. Together these behavioural and nervous system specializations have made star-nosed moles an intriguing model system for examining general and specialized aspects of mammalian touch.

A fundamental question in the neurosciences is how central nervous system (CNS) space is allocated to different sensory inputs. Yet it is difficult to measure innervation density and corresponding representational areas in the CNS of most species. These measurements can be made in star-nosed moles (Condylura cristata) because the cortical representation of nasal rays is visible in flattened sections and afferents from each ray can be counted. Here we used electrophysiological recordings combined with sections of the brainstem to identify a large, visible star representation in the principal sensory nucleus (PrV). PrV was greatly expanded and bulged out of the brainstem rostrally to partially invade the trigeminal nerve. The star representation was a distinct PrV subnucleus containing 11 modules, each representing one of the nasal rays. The 11 PrV ray representations were reconstructed to obtain volumes and the largest module corresponded to ray 11, the mole's tactile fovea. These measures were compared to fiber counts and primary cortical areas from a previous investigation. PrV ray volumes were closely correlated with the number of afferents from each ray, but afferents from the behaviorally most important, 11(th) ray were preferentially over-represented. This over-representation at the brainstem level was much less than at the cortical level. Our results indicate that PrV provides the first step in magnifying CNS representations of important afferents, but additional magnification occurs at higher levels. The early development of the 11(th), foveal appendage could provide a mechanism for the most important afferents to capture the most CNS space.

Corneal development and structure were studied in the Iberian mole Talpa occidentalis, which has permanently closed eyelids, and the European mole Talpa europaea, in which the eyes are open. The vertebrate cornea typically maintains a three-layered structure - a stratified epithelium with protective and sensory function, an avascular, hypocellular, collagenous stroma, and an endothelium with both barrier and transport functions that regulates corneal hydration, hence maintaining transparency. Compared to mouse, both mole species had significant corneal specializations, but the Iberian mole had the most divergent phenotype, with no endothelium and a flattened monolayer epithelium. Nevertheless, normal epithelial cell junctions were observed and corneal transparency was maintained. Corneas of European moles have a dysmorphic phenotype that recapitulates the human disorder keratoconus for which no mouse model exists. Mole corneas are vascularized - a situation only previously observed in the manatee Trichechus- and have non-radial patterns of corneal innervation indicative of failure of corneal epithelial cell migration. The transcription factor Pax6 is required for corneal epithelial differentiation in mice, but was found to be dispensable in moles, which had mosaic patterns of PAX6 localization uniquely restricted, in European moles, to the apical epithelial cells. The apparently stalled or abnormal differentiation of corneas in adult moles is supported by their superficial similarity to the corneas of embryonic or neonatal mice, and their abnormal expression of cytokeratin-12 and cytokeratin-5. European moles seem to have maintained some barrier/protective function in their corneas. However, Iberian moles show a more significant corneal regression likely related to the permanent eyelid fusion. In this mole species, adaptation to the arid, harder, Southern European soils could have favoured the transfer of these functions to the permanently sealed eyelids., (© 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.)

Animals adapted to dark ecotopes may experience selective pressure for retinal reduction. No previous studies have explicitly addressed the molecular basis of retinal development in any fossorial mammal. We studied retinal development and function in the Iberian mole Talpa occidentalis, which was presumed to be blind because of its permanently closed eyes. Prenatal retina development was relatively normal, with specification of all cell types and evidence of dorsoventral regionalization. Severe developmental defects occurred after birth, subsequent to lens abnormalities. 'Blind' Iberian moles had rods, cones and rod nuclear ultrastructure typical of diurnal mammals. DiI staining revealed only contralateral projections through the optic chiasm. Y-maze experiments demonstrated that moles retain a photoavoidance response. Over-representation of melanopsin-positive retinal ganglion cells that mediate photoperiodicity was observed. Hence, molecular pathways of eye development in Iberian moles retain the adaptive function of rod/cone primary vision and photoperiodicity, with no evidence that moles are likely to completely lose their eyes on an evolutionary time scale.

The goal of the investigation was to clarify the ways of subcutaneous muscles development in burrowing forms of insectivores--moles (Talpidae) and golden moles (Chrysochloridae). To achieve the goal the comparative morpho-functional analysis of subcutaneous and facial musculature of six mole genera (Neurotrichus, Urotrichus, Talpa, Mogera, Scalopus, Parascalops), two genera of chrysochlorids (Chrysochloris, Eremitalpa), and some other non-specialized forms of insectivorous mammals from Erinaceidae, Tenrecidae, Soricidae and Solenodontidae was carried out. It was shown that some of m. cutaneus trunci derivatives interact intimately with facial musculature. Besides, subcutaneous muscle forms additional layers that facilitate the operation of shaking ground particles off the for, which is rather important for burrowers. Overall complication of subcutaneous musculature in moles and chrysochlorids is accompanied by convergent similarity in the development of some musculature portions. At the same time some layers of m. cutaneus trunci seem to have evolved in different, special ways.

Background: Golden moles (Chrysochloridae) are small, subterranean, afrotherian mammals from South Africa and neighboring regions. Of the 21 species now recognized, some (e.g., Chrysochloris asiatica, Amblysomus hottentotus) are relatively common, whereas others (e.g., species of Chrysospalax, Cryptochloris, Neamblysomus) are rare and endangered. Here, we use a combined analysis of partial sequences of the nuclear GHR gene and morphological characters to derive a phylogeny of species in the family Chrysochloridae., Results: Although not all nodes of the combined analysis have high support values, the overall pattern of relationships obtained from different methods of phylogeny reconstruction allow us to make several recommendations regarding the current taxonomy of golden moles. We elevate Huetia to generic status to include the species leucorhinus and confirm the use of the Linnean binomial Carpitalpa arendsi, which belongs within Amblysominae along with Amblysomus and Neamblysomus. A second group, Chrysochlorinae, includes Chrysochloris, Cryptochloris, Huetia, Eremitalpa, Chrysospalax, and Calcochloris. Bayesian methods make chrysochlorines paraphyletic by placing the root within them, coinciding with root positions favored by a majority of randomly-generated outgroup taxa. Maximum Parsimony (MP) places the root either between chrysochlorines and amblysomines (with Chlorotalpa as sister taxon to amblysomines), or at Chlorotalpa, with the former two groups reconstructed as monophyletic in all optimal MP trees., Conclusions: The inclusion of additional genetic loci for this clade is important to confirm our taxonomic results and resolve the chrysochlorid root. Nevertheless, our optimal topologies support a division of chrysochlorids into amblysomines and chrysochlorines, with Chlorotalpa intermediate between the two. Furthermore, evolution of the chrysochlorid malleus exhibits homoplasy. The elongate malleus has evolved just once in the Cryptochloris-Chrysochloris group; other changes in shape have occurred at multiple nodes, regardless of how the root is resolved.

We investigated adult neurogenesis in two species of mammals belonging to the superorder Laurasiatheria, the southern white-breasted hedgehog (order Erinaceomorpha, species Erinaceus concolor) from Armenia and the European mole (order Soricomorpha, species Talpa europaea) from Poland. Neurogenesis in the brain of these species was examined immunohistochemically, using the endogenous markers doublecortin (DCX) and Ki-67, which are highly conserved among species. We found that in both the hedgehog and mole, like in the majority of earlier investigated mammals, neurogenesis continues in the subventricular zone (SVZ) of the lateral ventricles and in the dentate gyrus (DG). In the DG of both species, DCX-expressing cells and Ki-67-labeled cells were present in the subgranular and granular layers. In the mole, a strong bundle of DCX-labeled processes, presumably axons of granule cells, was observed in the center of the hilus. Proliferating cells (expressing Ki-67) were identified in the SVZ of lateral ventricles of both species, but neuronal precursor cells (expressing DCX) were also observed in the olfactory bulb (OB). In both species, the vast majority of cells expressing DCX in the OB were granule cells with radially orientated dendrites, although some periglomerular cells surrounding the glomeruli were also labeled. In addition, this paper is the first to show DCX-labeled fibers in the anterior commissure of the hedgehog and mole. These fibers must be axons of new neurons making interhemispheric connections between the two OB or piriform (olfactory) cortices. DCX-expressing neurons were observed in the striatum and piriform cortex of both hedgehog and mole. We postulate that in both species a fraction of cells newly generated in the SVZ migrates along the rostral migratory stream to the piriform cortex. This pattern of migration resembles that of the 'second-wave neurons' generated during embryonal development of the neocortex rather than the pattern observed during development of the allocortex. In spite of the presence of glial cells alongside DCX-expressing cells, we never found colocalization of DCX protein with a glial marker (vimentin or glial fibrillary acidic protein)., (Copyright © 2010 S. Karger AG, Basel.)

The placentation of the Hottentot golden mole (Amblysomus hottentotus) has been examined using light and electron microscopy and lectin histochemistry of nine specimens at both mid and late gestation. The placentae were lobulated towards the allantoic surface and the lobules contained roughly parallel arrays of labyrinthine structures converging on a central spongy zone. At mid gestation, the arrays were composed of an inner cellular and outer syncytial trophoblast layer, the inner layer enclosing scant connective tissue and fetal capillaries. Maternal blood spaces coursed through the outer trophoblast and were lined by trophoblastic microvilli; the blood spaces were narrow in mid gestation but enlarged near term, while the inner trophoblast layer became thinner and seemed to be syncytial. These features were confirmed by transmission electron microscopy. The microvillous surfaces and dispersed cytoplasmic particles were heavily glycosylated, as shown by lectin histochemistry, and exhibited changes with maturation, particularly a loss in N-acetyl glucosamine oligomers bound by Phytolacca americana lectin on the microvilli lining the maternal blood spaces and outer trophoblast particles. A substantial yolk sac was present both in mid and late gestation stages. It was clearly unattached to the uterus in the later stages. These morphological features are discussed in relation to the phylogenetic position of Amblysomus with respect to other members of Afrosoricida and Afrotheria.

Previous studies of the reproductive biology and genetics of European moles (Talpa spp.) showed that all females of these species have ovotestes (gonads with testicular and ovarian tissue) instead of normal ovaries, a unique specialization among mammals. Females are fertile as their ovarian tissue is fully functional. Testicular tissue is abnormal and sterile, but produces high levels of testosterone. This phenomenon also characterizes other talpid species from Europe and North America. To study the origin of this singular reproductive specialization, we examined the gonads of several female specimens belonging to two critical taxa. Although large Japanese moles (Mogera wogura) posses ovotestes, greater Japanese shrew moles (Urotrichus talpoides) are characterized by normal ovaries. The results fit parsimoniously with a recent phylogenetic study that places Urotrichus relatively basal in the talpid tree and separate from the American shrew mole. Parsimony reconstruction on alternative phylogenetic hypotheses clearly indicates that reversal(s) must have occurred and suggests that a relatively simple genetic mechanism must be associated with the evolution of female hermaphroditism in moles., ((c) 2007 Wiley-Liss, Inc.)

Eimer's organ is a small, densely innervated sensory structure found on the glabrous rhinarium of most talpid moles. This structure consists of an epidermal papilla containing a central circular column of cells associated with intraepidermal free nerve endings, Merkel cell neurite complexes, and lamellated corpuscles. The free nerve endings within the central cell column form a ring invested in the margins of the column, surrounding 1-2 fibers that pass through the center of the column. A group of small-diameter nociceptive free nerve endings that are immunoreactive for substance P surrounds this central ring of larger-diameter free nerve endings. Transmission electron microscopy revealed a high concentration of tonofibrils in the epidermal cells of the central column, suggesting they are more rigid than the surrounding keratinocytes and may play a mechanical role in transducing stimuli to the different receptor terminals. The intraepidermal free nerve endings within the central column begin to degrade 15 microm from the base of the stratum corneum and do not appear to be active within the keratinized outer layer. The peripheral free nerve endings are structurally distinct from their counterparts in the central column and immunocytochemical double labeling with myelin basic protein and substance P indicates these afferents are unmyelinated. Merkel cell-neurite complexes and lamellated corpuscles are similar in morphology to those found in a range of other mammalian skin., ((c) 2007 Wiley-Liss, Inc.)

The densities of middle ear ossicles of golden moles (family Chrysochloridae, order Afrosoricida) were measured using the buoyancy method. The internal structure of the malleus was examined by high-resolution computed tomography, and solid-state NMR was used to determine relative phosphorus content. The malleus density of the desert golden mole Eremitalpa granti (2.44 g/cm3) was found to be higher than that reported in the literature for any other terrestrial mammal, whereas the ossicles of other golden mole species are not unusually dense. The increased density in Eremitalpa mallei is apparently related both to a relative paucity of internal vascularization and to a high level of mineralization. This high density is expected to augment inertial bone conduction, used for the detection of seismic vibrations, while limiting the skull modifications needed to accommodate the disproportionately large malleus. The mallei of the two subspecies of E. granti, E. g. granti and E. g. namibensis, were found to differ considerably from one another in both size and shape.

The present studies were carried out on the brains of the adult mole and rabbit. The preparations were made by means of the Golgi technique and the Nissl method. Two types of neurons were distinguished in the preoptic area (POA) of both species: bipolar and multipolar. The bipolar neurons have oval, fusiform or round perikarya and two dendritic trunks arising from the opposite poles of the cell body. The dendrites bifurcate once or twice. The dendritic branches have swellings, single spine-like and filiform processes. The multipolar neurons usually have triangular and quadrangular perikarya and from 3 to 5 dendritic trunks. The dendrites of the mole neurons branch sparsely, whereas the dendrites of the rabbit neurons display 2 or 3 divisions. On the dendritic branches varicosities and different protuberances were observed. The general morphology of the bipolar and multipolar neurons is similar in the mammals studied, although the neurons of the rabbit POA display a more complicated structure. Their dendritic branches show more divisions and possess more swellings and different processes than the dendrites of the neurons of the mole POA. Furthermore, of the multipolar neurons only the dendrites in POA of the rabbit were observed to have a rosary-like beaded appearance.

Specialized species often reveal general principles of brain organization and provide systems for analysis of sensory function. Subterranean species dependent on touch have particularly large somatosensory areas with modular cortical representations of sensory surfaces. Some species have added cortical areas to processing networks, have developed tactile foveas and have superior colliculi primarily devoted to somatosensation rather than vision. Recent studies reveal surprisingly large cortical representations of oral structures in primates and mole-rats. Cortical modules represent a range of different sensory surfaces in rodents, star-nosed moles and primates, indicating that similar developmental mechanisms operate in diverse species. Finally, manipulation of patterning genes in mice suggests evolutionary mechanisms for producing the specialized corticies of subterranean species.

Talpid moles are small insectivores that live in dark underground tunnels. They depend heavily on touch to navigate and find food. Most species have an array of complex epidermal sensory structures called Eimer's organs that cover the tip of the nose. In this study, the anatomy of Eimer's organ was examined in the coast mole and star-nosed mole by using the fluorescent styryl pyridinium dye AM1-43 and immunocytochemical staining for neurofilament 200 and substance P. In addition, DiI was used to label neural components of Eimer's organ. AM1-43 labeled all of the Eimer's organ receptors after systemic injection, suggesting a role in mechanotransduction. Immunostaining with neurofilament 200 and substance P labeled distinct subtypes of sensory fibers. Substance P labeled a group of free nerve endings along the outer edge of Eimer's organ, indicating a nociceptive role for these fibers. In contrast, neurofilament 200 labeled a more central set of nerve endings, suggesting that these fibers function as low-threshold mechanoreceptors. By labeling subsets of trigeminal afferents distant from the receptor array with DiI, we revealed innervation patterns indicating that one afferent supplies the outer, substance P-positive set of free nerve endings, whereas several afferents differentially innervate the central free nerve endings. Our results suggest that the free nerve endings innervating Eimer's organ are largely mechanosensitive and may play an important role in the rapid sensory discrimination observed in these species.

The tongue in the adult European mole (Talpa europea L.) was examined by scanning electron microscope. The elongated tongue with a rounded apex is about 12-13 mm in length and 3-4 mm in width. On the apex the shallow median groove is present. On the dorsal surface of the lingual mucosa two types of mechanical papillae and two types of gustatory papillae were observed. Mechanical papillae are represented by numerous filiform papillae with a single process, covering the whole surface of the apex and body of the tongue, and massive conical papillae, found on the root of the tongue. The structure and density of filiform papillae varies in the anterior and posterior part of the tongue. A unique trait of the tongue in the European mole is the occurrence on the apex of the tongue of a single row of conical papillae. Gustatory papillae are represented by numerous fungiform papillae and one pair of vallate papillae. Dome-shaped fungiform papillae in the anterior part of the tongue are arranged linearly along both margins of the tongue, whereas in the posterior part of the body of the tongue flat fungiform papillae are distributed evenly among filiform papillae. Oval vallate papillae are surrounded by a continuous furrow and a single pad. In the posterior part of the root behind conical papillae the surface of the mucosa is flat with numerous orifices of lingual papillae located there. Observations on the distribution and structure of gustatory papillae in the common mole did not show the existence of special traits, differing them from those in terrestrial insectivores. The comparison of the morphology of the tongue, the distribution and structure of the lingual papillae in the European mole with those in the other species of Insectivores, indicated of a general similarity of features within the family Talpidae.

The middle ear structures of eight species of mole in the family Talpidae (Mammalia: Eulipotyphla) were studied under light and electron microscopy. Neurotrichus, Parascalops, and Condylura have a simple middle ear cavity with a loose ectotympanic bone, ossicles of a "microtype" morphology, and they retain a small tensor tympani muscle. These characteristics are ancestral for talpid moles. Talpa, Scalopus, Scapanus, and Parascaptor species, on the other hand, have a looser articulation between malleus and ectotympanic bone and a reduced or absent orbicular apophysis. These species lack a tensor tympani muscle, possess complete bullae, and extensions of the middle ear cavity pneumatize the surrounding basicranial bones. The two middle ear cavities communicate in Talpa, Scapanus, and Parascaptor species. Parascaptor has a hypertrophied malleus, a feature shared with Scaptochirus but not found in any other talpid genus. Differences in middle ear morphology within members of the Talpidae are correlated with lifestyle. The species with middle ears closer to the ancestral type spend more time above ground, where they will be exposed to high-frequency sound: their middle ears appear suited for transmission of high frequencies. The species with derived middle ear morphologies are more exclusively subterranean. Some of the derived features of their middle ears potentially improve low-frequency hearing, while others may reduce the transmission of bone-conducted noise. By contrast, the unusual middle ear apparatus of Parascaptor, which exhibits striking similarities to that of golden moles, probably augments seismic sensitivity by inertial bone conduction., (J. Morphol. (c) 2006 Wiley-Liss, Inc.)