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Ronald H H Kroger - One of the best experts on this subject based on the ideXlab platform.
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Dogs can sense weak thermal radiation
Scientific Reports, 2020Co-Authors: Anna Bálint, Attila Andics, Márta Gácsi, Anna Gábor, Kálmán Czeibert, Chelsey M. Luce, Ádám Miklósi, Ronald H H KrogerAbstract:The dog Rhinarium (naked and often moist skin on the nose-tip) is prominent and richly innervated, suggesting a sensory function. Compared to nose-tips of herbivorous artio- and perissodactyla, carnivoran rhinaria are considerably colder. We hypothesized that this coldness makes the dog Rhinarium particularly sensitive to radiating heat. We trained three dogs to distinguish between two distant objects based on radiating heat; the neutral object was about ambient temperature, the warm object was about the same surface temperature as a furry mammal. In addition, we employed functional magnetic resonance imaging on 13 awake dogs, comparing the responses to heat stimuli of about the same temperatures as in the behavioural experiment. The warm stimulus elicited increased neural response in the left somatosensory association cortex. Our results demonstrate a hitherto undiscovered sensory modality in a carnivoran species.
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A new type of somatosensory organ in the nasolabial skin of the dog.
Journal of Morphology, 2020Co-Authors: Rolf Elofsson, Ronald H H KrogerAbstract:A new morphological type of somatosensory organ is described. It is found in the glabrous skin of the dog nose (Rhinarium or planum nasale) and situated in dermis papillae. The otherwise thick epidermis forms a thin window above the organ. There are only a few layers of keratinocytes in the window and the corneocytes are much thinner than elsewhere. The organ consists of highly branching cells that wrap naked nerve endings emanating from myelinated nerve fibers originating in the outer dermal nerve plexus. The structure entirely fills the top of the dermal papilla. The intercellular spaces of the organ and its surroundings are occupied by an extended areolar basal lamina.
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Rhinarium temperature dynamics in domestic dogs
Journal of Thermal Biology, 2017Co-Authors: Ronald H H Kroger, Aitor Bereber GoiricelayaAbstract:Abstract Many mammals have specialized nose-tips with glabrous and often wet skin, called rhinaria. The function of the Rhinarium is unknown in most species. Rhinaria differ not only in shape and skin structure, but also in skin temperature. They are considerably colder in carnivorans than in herbivorous artio- and perissodactyls. Domestic dogs are carnivorans and their noses often feel cold, such that they can be used as an abundant and easily accessible model species. We performed a study on Rhinarium temperature in dogs under various ambient temperatures as well as in different behavioral and physiological contexts, breeds, and age groups. The rhinaria of adult, alert, and comfortable dogs are colder than ambient temperature from 30 °C (approximately 5 °C colder) down to a break point at about 15 °C. At an ambient temperature of 0 °C, Rhinarium temperature is approximately 8 °C and the decrease in skin surface temperature with decreasing ambient temperature has not yet leveled off. The dog Rhinarium warms up under a number of circumstances. In contrast to the continuously warm rhinaria of herbivores, our results suggest strongly that the cold state is the operating state of the dog Rhinarium.
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variation in Rhinarium temperature indicates sensory specializations in placental mammals
Journal of Thermal Biology, 2017Co-Authors: Nele Glaser, Ronald H H KrogerAbstract:Abstract The Rhinarium, a specialized nose-tip characterized by an area of naked and wet skin around the nostrils, is a typical mammalian structure. The type and amount of innervation suggests a sensory role and morphological diversity implies so far unidentified species-specific functional specializations. Rhinaria also vary in temperature and this may be related to the functions of these sensory organs. We performed a comparative study on Rhinarium temperature in order to learn more about possible correlations with phylogeny and ecology. We have concentrated on terrestrial carnivorans and large herbivores, but also investigated a number of other species, some of them lacking typical rhinaria. We used infrared (IR) thermography to determine nose skin temperatures from safe distances and without interfering with the animals’ behavior. In all groups studied, the temperature of the Rhinarium/nose-tip decreased with decreasing ambient temperature. At all ambient temperatures, Rhinarium temperature was lower, by 9–17 °C, in carnivorans compared to herbivores. Glires (rodents and lagomorphs), haplorrhine primates, and omnivorous Perisso- and Artiodactyla were intermediate. In strepsirrhine primates, Rhinarium temperature was similar to ambient temperature. Our findings in Strepsirrhini are consistent with the hypothesis that their rhinaria have an indirect role in chemical communication. Warm rhinaria in herbivores suggest a tactile function, while the low skin temperatures on carnivoran rhinaria may make the skin particularly sensitive to warming.
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synthetic smooth muscle in the outer blood plexus of the Rhinarium skin of lemur catta l
Journal of Smooth Muscle Research, 2017Co-Authors: Rolf Elofsson, Ronald H H KrogerAbstract:The skin of the lemur nose tip (Rhinarium) has arterioles in the outer vascular plexus that are endowed with an unusual coat of smooth muscle cells. Comparison with the arterioles of the same area in a number of unrelated mammalians shows that the lemur pattern is unique. The vascular smooth muscle cells belong to the synthetic type. The function of synthetic smooth muscles around the terminal vessels in the lemur Rhinarium is unclear but may have additional functions beyond regulation of vessel diameter.
Anna Bálint - One of the best experts on this subject based on the ideXlab platform.
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Dogs can sense weak thermal radiation
Scientific Reports, 2020Co-Authors: Anna Bálint, Attila Andics, Márta Gácsi, Anna Gábor, Kálmán Czeibert, Chelsey M. Luce, Ádám Miklósi, Ronald H H KrogerAbstract:The dog Rhinarium (naked and often moist skin on the nose-tip) is prominent and richly innervated, suggesting a sensory function. Compared to nose-tips of herbivorous artio- and perissodactyla, carnivoran rhinaria are considerably colder. We hypothesized that this coldness makes the dog Rhinarium particularly sensitive to radiating heat. We trained three dogs to distinguish between two distant objects based on radiating heat; the neutral object was about ambient temperature, the warm object was about the same surface temperature as a furry mammal. In addition, we employed functional magnetic resonance imaging on 13 awake dogs, comparing the responses to heat stimuli of about the same temperatures as in the behavioural experiment. The warm stimulus elicited increased neural response in the left somatosensory association cortex. Our results demonstrate a hitherto undiscovered sensory modality in a carnivoran species.
Dubovy P - One of the best experts on this subject based on the ideXlab platform.
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A fine structural localization of the non-specific cholinesterase activity in glomerular nerve formations (endings).
Zeitschrift für mikroskopisch-anatomische Forschung, 1990Co-Authors: Dubovy PAbstract:: Snout glabrous skin (Rhinarium) of the cat is innervated not only by typical simple lamellar corpuscles but also glomerular formations. In contrast to simple lamellar corpuscles, glomerular nerve formations are located away the dermal papillae. In cross sections, glomerular nerve formation consists of several axonal profiles enveloped by 1-2 cytoplasmic lamellae of Schwann cells. The space among them is filled by collagenous microfibrils and the basal lamina-like material. Capsule was composed from fibroblast-like cells without definite basal lamina. An electron-dense reaction product due to non-specific cholinesterase activity was associated with Schwann cells and their processes surrounding unmyelinated terminal portion of the sensory axons. Abundant reaction product was bound to the collagenous microfibrils and was deposited in extracellular matrix between Schwann cell processes. These results are further evidence for the presence of the non-specific cholinesterase molecules as integral component of the extracellular matrix in sensory corpuscles. On the basis of histochemical study two possible explanation are considered for functional involving of this enzyme in sensory nerve formations.
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Localization of met-enkephalin like immunoreactivity in the glabrous skin of the cat Rhinarium.
European Journal of Morphology, 1990Co-Authors: Vega Ja, Del Valle Me, Hernández Lc, Dubovy P, Bengoechea Me, Pérez-casas AAbstract:The presence of met-enkephalin like immunoreactivity (MEL IR) was investigated immunohisto-chemically in the glabrous skin of the cat Rhinarium using the peroxidase-antiperoxidase Sternberger's method. Neither sensory corpuscles nor nerve bundles show MEL IR. MEL IR was found in the epidermal Merkel cells, as well as in Langerhans cells and/or melanocytes. In dermal papillae the reaction results positive in a number of cells which could be identified as Schwann or pigmentary cells.
Marjorie Machado - One of the best experts on this subject based on the ideXlab platform.
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Variación intraespecífica en Cryptotis aroensis (Mammalia, Soricomorpha, Soricidae) de Venezuela
Therya, 2014Co-Authors: Franger J. García, Mariana Delgado-jaramillo, Marjorie MachadoAbstract:Introduction: In Venezuela, the genus Cryptotis Pomel 1848 is represented by four species: C . meridensis Thomas 1898, C . tamensis Woodman 2002, C . aroensis Quiroga-Carmona and Molinari 2012; and C . venezuelensis Quiroga-Carmona 2013 (Quiroga-Carmona and Molinari 2012; Quiroga-Carmona 2013). C . meridensis , and C . tamensis have been documented in the Andes (Cordillera de Merida, El Tama, and Sierra de Perija). On the other hand, C . aroensis , and C . venezuelensis are recorded only in the Cordillera de la Costa (Sierra de Aroa, and Serrania del Litoral). Cryptotis aroensis , was recently described and is known from only three specimens from type locality (Sector Milla, Sierra de Aroa, Yaracuy State), in Northern Venezuela. Based on a new series (45 specimens) from Yurubi National Park, Sierra de Aroa, Yaracuy State, Venezuela, in this article, we evaluated the intraspecifi c variations of Cryptotis aroensis , previously unknown in the literature. Metodology: Specimens studied are preserved in the Museo de la Estacion Biologica de Rancho Grande (EBRG, Aragua State, Venezuela), and the Museo de Zoologia, Universidad de Carabobo (MZUC, Carabobo, State, Venezuela). External measurements (mm) and weight (g) were taken from the colector’s tag. Craniodental terminology follows Woodman (2002, 2003), Quiroga-Carmona and Molinari (2012), and Woodman et al . (2013), and the craniodental measurements were taken with a digital caliper. Finally, for each measure, mean and range were calculated and we used a Student t test with intervals confi dence not less than 95% to explore differences related to sex. Results: Our morphological and metric analysis indicates that specimens of Cryptotis aroensis from Yurubi National Park are smaller and with longer tails, compared with C . meridensis , C. tamensis and C. venezuelensis . There were no signifi cant differences between sexes for the individuals studied, suggesting that there is no sexual dimorphism in C . aroensis . Within this sample there were highly variable morphological characters such as the shape of the wart on the nasolabial groove in the Rhinarium, numbers of postnasal warts on the muzzle, hindlimb digits, presence and position of the fourth unicuspid tooth, presence and size of dorsal foramina on the skull, presence and size of foramina on posterior border of tympanic process of petromastoids. The humerus was slightly smaller, less robust and slightly curved in C . aroensis compared with one humerus available for C . meridensis . Discussion: The high intraspecifi c variation in C . aroensis is consistent with previous reports that indicates a high morphological and metric variation among individuals in the groups Cryptotis nigrescens (Woodman and Timm 1993), C . goldmani (Woodman and Timm 1999; Woodman 2011), C . thomasi (Woodman 2002), C . mexicana (Ramirez-Pulido et al . 2004), and C . parva (Ramirez-Pulido et al . 2004). With respect to the characters in the original description of C . aroensis (Quiroga-Carmona and Molinari 2012), there are similarities when the sample increases from three (holotype and two paratypes) to 45 specimens. Such characters include body-head length, and length of mandible, besides the presence of cusps on the third upper molar that defi ne a complex molar. Additionally, the result of this study suggests that tail length (extremely long) can be useful to separate C . aroensis of the different taxa in Venezuela. When we compared the type series of C . venezuelensis , a species known only from three specimens from the Cordillera de la Costa, like C . aroensis (Quiroga-Carmona 2013), there are several similarities in morphology and metrics. Those characters include its size and body coloration, presence and visibility of the fourth unicuspid tooth, shape of the wart and its extension on the nasolabial groove in the Rhinarium, the numbers of postnasal warts, size and shape of the angular and coronoid processes, and the average of scales per centimeter on the tail. These characters suggest that C . aroensis and C . venezuelensis might be closely related taxa.
Marcial Quiroga-carmona - One of the best experts on this subject based on the ideXlab platform.
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UNA NUEVA ESPECIE DE MUSARAÑA DEL GÉNERO Cryptotis (SORICOMORPHA: SORICIDAE) DE LA SERRANÍA DEL LITORAL EN EL NORTE DE VENEZUELA
Mastozoología neotropical, 2013Co-Authors: Marcial Quiroga-carmonaAbstract:A new species of shrew of the genus Cryptotis (Soricomorpha: Soricidae) from the Serrania del Litoral, Northern Venezuela. The presence of the genus Cryptotis in the Serrania del Litoral (north of Venezuela), is known only by a specimen collected in El Junquito more than 40 years ago, referred by this time to C. thomasi. Recently, two new specimens were collected in a locality near to the first finding (approxi - mately 15 km). With the revision and morphological comparison (skull and body) of the three specimens now available, it was determined that this population represents a new species belonging to the C. thomasi group, and can be differentiated by the following combination of characteristics: philtrum with a long and thin wart, extending from the base of the Rhinarium to the mouth; toes with well developed granular scales juxtaposed and arranged in three longitudinal lines; tail with large scales (26 cm); lacrimal foramen wide and deep; angu- lar process straight, short and wide; high coronoid process and tilted forward. This population represents the second species of Cryptotis with non-Andean distribution in South America, and increases to five the number of endemic mammals of the Cordillera de la Costa, Venezuelan ecoregion that currently faces serious problems of conservation by habitat loss.