Ecological differences between two sympatric species of armadillos (Xenarthra,Mammalia) in a temperate region of Argentina

Morpho-physiological specialization related to foraging can act as constraints on behaviour and ecological patterns of abundance and distribution. We tested this prediction in two species (weeping or screaming hairy armadillos Chaetophractus vellerosus Gray, 1865 and mulitas Dasypus hybridus Desmarest, 1804) that represent the two subfamilies of armadillos (Dasypodidae, Xenarthra): Euphractinae and Dasypodinae. The first subfamily possesses a well-developed masticatory apparatus that is considered primitive within the Xenarthra, while Dasypodinae show reductions in various aspects of cranial morphology. We sampled signs (burrows and foraging holes) and captured both species on 34 farms randomly selected in the north-eastern Pampas region of Argentina. We analyzed several niche dimensions. The two species showed significant differences in habitat use, seasonal patterns and diet. Weeping armadillos were generalists in their diet and active throughout the year. They were associated with calcareous-sand soil, as expected for a burrowing animal of the deserts. They tolerated a wide range of environmental conditions. We found that mulitas are myrmecophagous, and that they demonstrated a reduction in body temperature and activity during the cold season. As expected from their geographical distribution, mulitas used mainly vegetation with high cover and were associated with humic soils. Niche segregation between the two species of armadillos appeared to originate from different degrees of dietary specialization.     

A new species of Dasypodidae (Xenarthra: Cingulata) from the late Miocene of northwestern South America: implications in the Dasypodini phylogeny and diversity

A new species of dasypodid armadillo (Xenarthra, Cingulata), Anadasypus aequatorianus, from the late Miocene of Ecuador is described. The remains were collected in sediments of the Letrero Formation, Nabón Basin, which is part of several intermontane basins related to Andean uplift. The genus represents the oldest record of Dasypodini, which also encompasses Propraopus (Pleistocene–early Holocene) and Dasypus (?Miocene–Recent). The new species is based on several osteoderms, which show more derived features than Anadasypus hondanus, from the middle Miocene of Colombia. In order to test the affinities of A. aequatorianus within Dasypodini, we conducted a cladistic analysis of 24 morphological characters for 10 taxa. The most parsimonious tree supports the generic attribution of the new species and places Anadasypus basal to Propraopus and Dasypus, agreeing with the stratigraphic evidence. The faunas from tropical Andean areas differ noticeably from the better-known assemblages of the classic South American sequences. In the case of dasypodines, their geochronological distribution shows that they were historically restricted to tropical and subtropical environments and the main cladogenetic events of the group probably occurred at lower latitudes. In this context, the taxon described herein fills important temporal and geographic gaps of early Neogene armadillos from intertropical areas.http://www.zoobank.org/urn:lsid:zoobank.org:pub:9DC76603-D831-4E68-BE55-90113228E0F4     

Female reproductive tract of the lesser anteater (Tamandua tetradactyla,myrmecophagidae, Xenarthra). Anatomy and histology

The morphological and histological features of the unusual reproductive tract of the female lesser anteater, Tamandua tetradactyla (Myrmecophagidae, Xenarthra), are described for the first time. The present study aimed to establish the main similarities and differences between this species and other xenarthrans. The populations of this species are declining rapidly for a number of reasons and our study is relevant to diverse programs related to its conservation. Studies were carried out on five female genital tracts of adult specimens. Ovaries were ovoid, presenting a medulla completely surrounded by the cortex, differently from that described in other xenarthans. Like in Dasypus but different from all other armadillos studied, single oocyte follicles were observed and a simple the uterus. The uterovaginal canal connects the uterus with the urogenital sinus. The simple columnar epithelium of the uterovaginal canal ends abruptly at a septum which resembles a hymen, where the transitional epithelium of the urogenital sinus appears. This ancestral feature is shared with that of other armadillos, except Tolypeutes matacus, which has a true vagina. Characteristics of the reproductive tract and sperm morphology of other Xenarthra are comparatively discussed. These observations suggest that important reproductive features are shared between the family Myrmecophagidae and the genus Dasypus, a basal group in the phylogeny of Xenarthra. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.     

The skin of primates. XL. The skin of the cottontop pinché Saguinus (=Oedipomidas) oedipus

The skin of Saguinus (= Oedipomidas) oedipus Linnaeus, is basically similar to that of the red-mantled tamarin, Saguinus (= Tamarinus) fuscicollis Spix; it has several peculiarities: (1) a circumscribed tuft of vibrissae on the ulnar aspect of the wrist; (2) an accumulation of apocrine glands over the sternum; and (3) an extensive posterior abdominal field of gigantic sebaceous glands admixed with large apocrine glands, better developed in the female. The epidermis, dermis, hair follicles, sebaceous ducts, and apocrine excretory ducts are all heavily pigmented. Hairs are arranged in linear perfect sets; the epithelial sac of quiescent follicles is devoid of glycogen and phosphorylase. Eccrine sweat glands are restricted to the volar friction surfaces and contain no glycogen. Only the coiled excretory ducts of the eccrine glands contain phosphorylase. All cutaneous nerve fibers are more reactive for acetylthan butyrylcholinesterase.     

HISTOLOGY AND CYTOCHEMISTRY OF HUMAN SKIN : IX. THE DISTRIBUTION OF NON-SPECIFIC ESTERASES

1. In the epidermis non-specific esterase activity outlines a strongly reactive band between the stratum granulosum and the stratum corneum. In the epidermis of the palm, there is no such esterase-rich band. 2. The outer sheath of active hair follicles has strong enzyme activity. The degenerating hair bulb in catagen follicles is very strongly reactive, and clusters of cells around the hair club in quiescent follicles are rich in enzyme activity. 3. Strong enzyme activity is found in young sebaceous cells, while decaying sebaceous cells and newly formed sebum are unreactive. Old sebum, however, is very intensely reactive. 4. Only the "dark" cells of eccrine sweat glands show a reaction; the "clear" cells are negative. 5. The cells of axillary apocrine glands abound in enzyme.     

Micromorphology of osteoderms in Dasypodidae (Cingulata,Mammalia): Characterization and 3D-reconstructions

Osteoderms are present in a variety of extinct and extant vertebrates, but among mammals, the presence of osteoderms is essentially restricted to armadillos (Cingulata, Dasypodidae). Osteoderms have been proposed to exhibit a variety of functionalities in Dasypodidae, mainly protection and thermoregulation, and they have been considered as one of the synapomorphies of this group. In this study, we use high-resolution microcomputed tomography to describe the osteoderm micromorphology of several extant species of Dasypodidae in a comparative context. This study allowed the identification, 3D-reconstruction and volume quantification of different internal structures of osteoderms as well as their interrelations. This detailed characterization of the internal osteoderm morphology was compared in a phylogenetic context to assess the evolutionary trends of the species involved. This enables the identification of distinctive patterns for the most widely recognized clades, the Dasypodinae and Euphractinae with a morphological homogeneity in the microstructure of their osteoderms, in comparison with Tolypeutinae where it has not been possible to establish a common morphological pattern. The most important features for linage differentiation is the degree of compaction of the osteoderms, the number of cavities and the development of hairs. It is likely that the differential development of the various structures occurred as adaptive response to climate changes.     

An Overview of the Presence of Osteoderms in Sloths: Implications for Osteoderms as a Plesiomorphic Character of the Xenarthra

The presence of osteoderms in the skin of some extinct sloths and in cingulates (armadillos, pampatheres, and glyptodonts) has often been considered a pleisomorphic character of the Xenarthra. While osteoderms are known from the earliest cingulates, they are absent in most sloths including the two extant taxa and only appear late in their fossil record. Osteoderms are currently only reported from five genera of mylodonts and two megatheres, out of the over 100 currently recognized genera of sloths. Consequently, rather than a plesiomorphic character of the Xenarthra, which has been secondarily lost in sloths, it is more likely that osteoderms in sloths are the result of parallel evolution to the cingulates that independently evolved in one, possibly two different sloth clades.     

Germ cell cysts,a fetal feature in mammals,are constitutively present in the adult armadillo

Formation and subsequent break down of ovarian germ cell (GC) cysts is a key and an evolutionary‐conserved developmental event, described in phylogenetically diverse species of invertebrates and vertebrates. In mammals, cyst break down (CBD) ends at the time of, or soon after, birth with the formation of primordial follicles enclosing single oocytes, which constitute the sole reservoir of gametes available through the whole female's reproductive life. In this study, we challenge this paradigm demonstrating the constitutive presence of a large number of cysts, enclosing two‐thirty GCs, in the ovary of the adult armadillo Chaetophractus villosus, belonging to the superorder Xenarthra, one of the earliest offshoots among placentals. We also describe that (a) GCs enclosed within cysts are connected by intercellular bridges—intercellular bridges—markers of their clonal origin; (b) CBD occurs through four main phases, ending with primordial follicles containing single oocytes; (c) GCs encompass meiotic prophase I stages, from leptotene to diplotene; (d) seasonal variations in the number of GCs enclosed within cysts, suggesting the presence of a GC multiplying activity. The armadillo C. villosus''s ovary emerges as an extraordinary resource to investigate folliculogenesis and to explore the evolutionary past of the mammalian ovary.     

The skin of primates. XXIX. The skin of the pigmy bushbaby (Galago demidovii)

The skin of the pigmy bushbaby (Galago demidovii), the smallest existing prosimian, is largely similar to that of the other African Lorisidae, although this animal has certain peculiar features. The very thin epidermis contains alkaline phosphatase-reactive dendritic cells which resemble those in the other bushbabies and the potto. The hair follicles of this animal are similar to those of the lesser bushbaby, while the sebaceous glands are different from those of the other bushbabies in being reactive for alkaline phosphatase. The histological and histochemical properties of the sweat glands are similar to those of the other bushbabies.     

Una nueva especie de Neuryurus Ameghino (Mammalia, Glyptodontidae) en el Pleistoceno tardío de la Mesopotamia de Argentina

Among the South American Pleistocene Glyptodontidae (Xenarthra, Cingulata), one of the most scarcely represented genus in the fossil record is Neuryurus Ameghino, in which the only well characterized species, until now, is Neuryurus rudis (Gervais), coming from the Ensenadan (early-middle Pleistocene) of the Pampean region, Argentina. In this contribution, we report and describe a new species of Neuryurus, coming from the Arroyo Feliciano Formation (early Lujanian; ca. 130 ka), Entre Ríos province, Argentina, in a particular palaebiogeographic context, more associated with the western sector of Uruguay and southern Brazil than the Pampean region. From a morphological perspective, this new taxon is characterized by: (a) the remarkable development of the foramina at the exposed surface of the osteoderms of the dorsal carapace, showing un aspect almost spongy; (b) the large diameter of the perforations observed in the ventral surface of the osteoderms, resembling to those present in the dorsal surface of the osteoderms of the Glyptodontidae Doedicurinae; (c) the evident thickness of the osteoderms, as in Glyptodon Owen; (d) area of contact and articulation of adjacent osteoderms very denticulate, with deep osseous interdigitating projections, as in Glyptodon and Glyptotherium Osborn, but here more evident; (e) larger osteoderms of the dorsal carapace showing, in the dorsal surface, many little conical tubercles, having some resemblance to Panochthus tuberculatus Burmeister. The presence of this new species in the early late Pleistocene of the Mesopotamic region is another element that adds to the biogeographical characterization of this particular area, especially evident during the warm and humid pulses of the late Pleistocene. In turn, this species represents the most complete record of the genus outside the Pampean region and partially complete the stratigraphic and geographic distribution of the genus.     

Histology and cytochemistry of human skin. IX. The distribution of non-specific esterases

1. In the epidermis non-specific esterase activity outlines a strongly reactive band between the stratum granulosum and the stratum corneum. In the epidermis of the palm, there is no such esterase-rich band. 2. The outer sheath of active hair follicles has strong enzyme activity. The degenerating hair bulb in catagen follicles is very strongly reactive, and clusters of cells around the hair club in quiescent follicles are rich in enzyme activity. 3. Strong enzyme activity is found in young sebaceous cells, while decaying sebaceous cells and newly formed sebum are unreactive. Old sebum, however, is very intensely reactive. 4. Only the "dark" cells of eccrine sweat glands show a reaction; the "clear" cells are negative. 5. The cells of axillary apocrine glands abound in enzyme.     

Two optical coherence tomography systems detect topical gold nanoshells in hair follicles,sweat ducts and measure epidermis

Optical coherence tomography (OCT) is an established imaging technology for in vivo skin investigation. Topical application of gold nanoshells (GNS) provides contrast enhancement in OCT by generating a strong hyperreflective signal from hair follicles and sweat glands, which are the natural skin openings. This study explores the utility of 150 nm diameter GNS as contrast agent for OCT imaging. GNS was massaged into skin and examined in four skin areas of 11 healthy volunteers. A commercial OCT system and a prototype with 3 μm resolution (UHR‐OCT) were employed to detect potential benefits of increased resolution and variability in intensity generated by the GNS. In both OCT‐systems GNS enhanced contrast from hair follicles and sweat ducts. Highest average penetration depth of GNS was in armpit 0.64 mm ± SD 0.17, maximum penetration depth was 1.20 mm in hair follicles and 15 to 40 μm in sweat ducts. Pixel intensity generated from GNS in hair follicles was significantly higher in UHR‐OCT images (P = .002) and epidermal thickness significantly lower 0.14 vs 0.16 mm (P = .027). This study suggests that GNSs are interesting candidates for increasing sensitivity in OCT diagnosis of hair and sweat gland disorders and demonstrates that choice of OCT systems influences results.      

Potential alteration of cross‐ecosystem resource subsidies by an invasive aquatic macroinvertebrate: implications for the terrestrial food web

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Morphological and histological features of the integument of the New Zealand sea lion Phocarctos hookeri

Abstract

Morphological and histological features of the integument of 2 Hooker’s sea lions, obtained dead in February, were examined. In a 3- week-old pup there were 7 rows of mystacial vibrissae, comprising 40 on the left side of the muzzle and 38 on the right. In the skin of the torso the guard hairs were in the quiescent phase of their growth cycle. In a 2½-year-old specimen a moult was imminent; guard hairs in quiescent follicles were about to be displaced by fibres in developing follicles. Histological features of the older sea lion, which may have been age-related, were coarser collagen bundles in the reticular layer of the dermis and a greater number of secondary follicles. In guard hair follicles of both animals the sweat gland duct opened above the sebaceous gland duct.     

Molecular systematics of armadillos (Xenarthra,Dasypodidae): contribution of maximum likelihood and Bayesian analyses of mitochondrial and nuclear genes

The 30 living species of armadillos, anteaters, and sloths (Mammalia: Xenarthra) represent one of the three major clades of placentals. Armadillos (Cingulata: Dasypodidae) are the earliest and most speciose xenarthran lineage with 21 described species. The question of their tricky phylogeny was here studied by adding two mitochondrial genes (NADH dehydrogenase subunit 1 [ND1] and 12S ribosomal RNA [12S rRNA]) to the three protein-coding nuclear genes (alpha2B adrenergic receptor [ADRA2B], breast cancer susceptibility exon 11 [BRCA1], and von Willebrand factor exon 28 [VWF]) yielding a total of 6869 aligned nucleotide sites for thirteen xenarthran species. The two mitochondrial genes were characterized by marked excesses of transitions over transversions-with a strong bias toward CT transitions for the 12S rRNA-and exhibited two- to fivefold faster evolutionary rates than the fastest nuclear gene (ADRA2B). Maximum likelihood and Bayesian phylogenetic analyses supported the monophyly of Dasypodinae, Tolypeutinae, and Euphractinae, with the latter two armadillo subfamilies strongly clustering together. Conflicting branching points between individual genes involved relationships within the subfamilies Tolypeutinae and Euphractinae. Owing to a greater number of informative sites, the overall concatenation favored the mitochondrial topology with the classical grouping of Cabassous and Priodontes within Tolypeutinae, and a close relationship between Euphractus and Chaetophractus within Euphractinae. However, low statistical support values associated with almost equal distributions of apomorphies among alternatives suggested that two parallel events of rapid speciation occurred within these two armadillo subfamilies.     

Antifungal activity of Moroccan medicinal plants against citrus sour rot agent Geotrichum candidum

Aims: The aim of this work was to find an alternative to the chemical fungicides currently used in the control of Geotrichum candidum, the causal agent of citrus sour rot. Methods and Results: Minimal inhibition concentrations (MIC) and minimal fungicidal concentrations (MFC) were determined using agar dilution method. The methanol extracts of Cistus villosus, Ceratonia siliqua and Halimium umbellatum exhibited strong antifungal activity with MIC values ranged between 0·156 and 1·25 mg ml^?1, and MFC values ranged between 2·5 and 5 mg ml^?1. Incidence of sour rot was lowered to 0·00, 3·33 and 11·66% when mandarin fruit was treated with C. villosus, C. siliqua and H. umbellatum methanol extracts at 50 mg ml^?1, respectively, compared with 95% in the control. Conclusions: Cistus villosus, C. siliqua and H. umbellatum methanol extracts successfully reduced the disease incidence caused by G. candidum, and no phytotoxic effects were recorded on citrus fruit. Significance and Impact of the Study: These findings suggest that C. villosus, C. siliqua and H. umbellatum plants may be useful and effective agents for control of citrus sour rot. Such natural products therefore represent a sustainable alternative to the use of synthetic fungicides.     

Characterization of Hair Follicle Development in Engineered Skin Substitutes

Generation of skin appendages in engineered skin substitutes has been limited by lack of trichogenic potency in cultured postnatal cells. To investigate the feasibility and the limitation of hair regeneration, engineered skin substitutes were prepared with chimeric populations of cultured human keratinocytes from neonatal foreskins and cultured murine dermal papilla cells from adult GFP transgenic mice and grafted orthotopically to full-thickness wounds on athymic mice. Non-cultured dissociated neonatal murine-only skin cells, or cultured human-only skin keratinocytes and fibroblasts without dermal papilla cells served as positive and negative controls respectively. In this study, neonatal murine-only skin substitutes formed external hairs and sebaceous glands, chimeric skin substitutes formed pigmented hairs without sebaceous glands, and human-only skin substitutes formed no follicles or glands. Although chimeric hair cannot erupt readily, removal of upper skin layer exposed keratinized hair shafts at the skin surface. Development of incomplete pilosebaceous units in chimeric hair corresponded with upregulation of hair-related genes, LEF1 and WNT10B, and downregulation of a marker of sebaceous glands, Steroyl-CoA desaturase. Transepidermal water loss was normal in all conditions. This study demonstrated that while sebaceous glands may be involved in hair eruption, they are not required for hair development in engineered skin substitutes.     

Localization of sex steroid receptors in human skin

Sex steroid hormones are involved in regulation of skin development and functions as well as in some skin pathological events. To determine the sites of action of estrogens, androgens and progestins, studies have been performed during the recent years to accurately localize receptors for each steroid hormone in human skin. Androgen receptors (AR) have been localized in most keratinocytes in epidermis. In the dermis, AR was detected in about 10% of fibroblasts. In sebaceous glands, AR was observed in both basal cells and sebocytes. In hair follicles, AR expression was restricted to dermal papillar cells. In eccrine sweat glands, only few secretory cells were observed to express AR. Estrogen receptor (ER) alpha was poorly expressing, being restricted to sebocytes. In contrast, ERbeta was found to be highly expressed in the epidermis, sebaceous glands (basal cells and sebocytes) and eccrine sweat glands. In the hair follicle, ERbeta is widely expressed with strong nuclear staining in dermal papilla cells, inner sheath cells, matrix cells and outer sheath cells including the buldge region. Progesterone receptors (PR) staining was found in nuclei of some keratinocytes and in nuclei of basal cells and sebocytes in sebaceous glands. PR nuclear staining was also observed in dermal papilla cells of hair follicles and in eccrine sweat glands. This information on the differential localization of sex steroid receptors in human skin should be of great help for future investigation on the specific role of each steroid on skin and its appendages.     

The skin of primates. XLI. The skin of the silver marmoset—Callithrix (= Mico) Argentata

The skin of the silver marmoset, Callithrix (= Mico) argentata Linnaeus, has many outstanding characteristics. The unusually thin epidermis and dermis are generally devoid of melanotic melanocytes. The surface of the interramal gular region is peppered with small, elevated papillae; that of the corpus penis is characterized by keratinized, proximally directed hollow spines in whose cavities are organized nerve end-organs and capillary loops. Cholinesterase-reactive papillary nerve end-organs and Meissner corpuscles populate all volar friction surfaces. A highly vascular dermis and subcutaneous fat pad partially contribute to the characteristic rubicund color of the face, external ears, and anogenital region. Many body surface hairs are accompanied by the classic Haarscheibe of Pinkus. Sinus hairs are plentiful; a circumscribed vibrissa-bearing eminence is located on the ventral ulnar aspect of each wrist. Alkaline phosphatase-positive, stellate-shaped cells are found on the outer root sheath and epithelial sac of active and quiescent hairs in all cephalic regions; such cells are not argyrophilic, aurophilic, or osmiophilic. Hairs grow in linear perfect sets of 3 to 5 follicles; they do not grow singly on the cheek. Large sebaceous glands contain alkaline phosphatase in their peripheral acini; extensive fields of gigantic multilobular sebaceous glands contribute to the distinct, opaque-white color of the scrotal skin. Numbers of apocrine sweat glands are diminished in cephalic regions but one gland occurs with each hair follicle in the axilla, scrotum, suprapubic region, and ulnar eminence. Relatively avascular eccrine sweat glands are confined to the volar friction surfaces. Their secretory coils contain sporadically distributed glycogen and phosphorylase and surrounding nerves are much more reactive for acetyl- than butyrylcholinesterase.     

Sero-systematics ofCytisus sect.Trianthocytisus (Fabaceae)

The serological reaction of seed proteins provides evidence for a partly new systematic arrangement ofCytisus sect.Trianthocytisus and ofCytisus s.l. Proposed modifications agree with recent advances in morphological taxonomy. Sect.Trianthocytisus includes only two species,C. villosus andC. aeolicus. Its position is central within the genus, and this fact agrees with the proposed retypification ofCytisus (type species:C. villosus).C. emeriflorus, formerly included in the same section, constitutes the monospecific sect.Emeroides, which is intermediate towards the genusLembotropis. This is serologically isolated and includes onlyL. nigricans. It is confirmed thatC. sessilifolius should be removed from the genusCytisus as a monospecific genus:Cytisophyllum Lang which is closely allied toHesperolaburnum and toPodocytisus, the most primitive genera ofGenisteae.