Mandibles of representatives of the Holarctic crayfish families Astacidae, Cambaridae, and Cambaroididae were examined using SEM, and the results were analyzed in a phylogenetic framework. The intraspecific variability of the incisor process was found to be higher than its interspecific variability, mainly due to extensive abrasion of its ridge during intermolt periods. The plesiomorphic state of the crayfish mandibles highlights the dentate-crenate type of the incisor process and the extensive ribbed molar field with a multicuspidate caudal part, typical of the two parastacid crayfish examined for comparison. For Holarctic crayfish, the initial evolutionary type of the incisor is also the dentate-crenate one, but the molar field has a bowl-shaped caudal part and reduced cephalic part, both of which have been shown, for example, for Cambaroides. Similar mandibles are also widely present in American cambarids, which further evolved a blade-like incisor process (some Faxonius spp.) or a tricuspidate or double-bladed caudal molar field (some Procambarus spp.). The molar field in Astacidae crayfish is subdivided and rugose. The results of the present study indicate that little phylogenetic information is conveyed by the mandible shape at the species or genus level. Evolutionary changes are indicated mainly on the level of the main crayfish families. RESEARCH HIGHLIGHTS: Mandible shape can be an additional characteristic to distinguish crayfish families and selected genera. Obvious differences exist in the molar process rather than in the incisor ridge.

• Klíčová slova
• astacidae, cambaridae, cambaroididae, crustacea, decapoda, parastacidae,
• MeSH
• anatomie srovnávací * MeSH
• biologická evoluce * MeSH
• druhová specificita MeSH
• fylogeneze MeSH
• mandibula anatomie a histologie   diagnostické zobrazování   MeSH
• řezáky diagnostické zobrazování   MeSH
• severní raci anatomie a histologie   MeSH
• shazování tělního pokryvu MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Although it is known that separate insect body structures may be asymmetrical within one species, the different functional asymmetries within a single organ as a result of differential selective regimes have not been described. Based on microscopic measurements and SEM photography, we examined the size, shape and asymmetry of the mandibular structures of males and females of the sexually dimorphic broad-horned flour beetle, Gnatocerus cornutus (Tenebrionidae, Coleoptera). It was found that sexual dimorphism only manifests in certain outgrowth parts (horns) of male mandibles, while the remaining cutting parts of the mandibles hold identical morphologies for both sexes. A more interesting finding-since this is the first published case of dual functionally selected asymmetry in an identical arthropod organ-was that the cutting part of the male mandible exhibited directional asymmetry, whereas the outgrowth horn part of the mandible showed a high degree of symmetry. Moreover, there was no relationship between the size and asymmetry of horns. The results indicate different regulatory mechanisms of sexually selected combative horns and the food-functional, more conservative (constrained by hard food and adult long life) cutting parts of mandibles.

• Klíčová slova
• asymmetry, mandibles, secondary sexual trait, sexual dimorphism, stored-product pest,
• Publikační typ
• časopisecké články MeSH

A macroscopic, microscopic and scanning electron microscope study was performed on the pathological bone changes of the mandibles of wild red deer (n = 61) exhibiting severe dental fluorosis. The animals originated from a highly fluoride polluted area in Central Europe (Ore mountains and their southern foreland, Czech-German border region) and constituted 11.2 % of the studied red deer sample (n = 545) from this area. Pathologically increased wear and fracture of fluorosed teeth caused a variety of mandibular bone alterations, including periodontal breakdown, periostitis, osteitis and chronic osteomyelitis. As a further consequence of severe dental attrition, opening of the pulp chamber and formation of periapical abscesses were occasionally observed. In case of severe periodontal breakdown, loss of teeth from the mandibles was found. In addition to the inflammatory bone changes, the occurrence of osteofluorotic alterations was also diagnosed in the specimens with the highest bone fluoride concentrations (> 4000 mg F-/kg dry wt). These changes comprised extended apposition of periosteal bone onto the mandibular cortex as well as deformation of the mandibular body, which was attributed to a fluoride-induced osteomalacia. The present study provided circumstantial evidence that, in addition to fluoride induced dental lesions, the occurrence of marked periodontal disease and tooth loss is an important factor responsible for a reduction of life expectancy in severely fluorotic wild red deer.

• MeSH
• dentální fluoróza patologie   veterinární   MeSH
• fluoridy * MeSH
• mandibula patologie   ultrastruktura   MeSH
• mikroskopie elektronová rastrovací MeSH
• vysoká zvěř anatomie a histologie   MeSH
• znečištění životního prostředí * MeSH
• ztráta zubů chemicky indukované   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Německo MeSH
• Názvy látek
• fluoridy * MeSH

Termites have developed a wide array of defensive mechanisms. One of them is the mandibulate soldier caste that crushes or pierces their enemies. However, in several lineages of Termitinae, soldiers have long and slender mandibles that cannot bite but, instead, snap and deliver powerful strikes to their opponents. Here, we use morphological and molecular evidence to describe Roisinitermesebogoensis Scheffrahn, gen. & sp. n. from near Mbalmayo, Cameroon. Soldiers of R.ebogoensis are unique among all other kalotermitid soldiers in that they possess snapping mandibles. The imago of R.ebogoensis is also easily distinguished from all other Kalotermitidae by the lack of ocelli. Our study reveals a new case of parallel evolution of snapping mandibles in termites, a complex apparatus responsible of one of the fastest biological acceleration rates measured to date.

• Klíčová slova
• Ethiopian Region, mandibles, ocellus, taxonomy,
• Publikační typ
• časopisecké články MeSH

One key event in insect evolution was the development of mandibles with two joints, which allowed powerful biting but restricted their movement to a single degree of freedom. These mandibles define the Dicondylia, which constitute over 99% of all extant insect species. It was common doctrine that the dicondylic articulation of chewing mandibles remained unaltered for more than 400 million years. We report highly modified mandibles overcoming the restrictions of a single degree of freedom and hypothesize their major role in insect diversification. These mandibles are defining features of parasitoid chalcid wasps, one of the most species-rich lineages of insects. The shift from powerful chewing to precise cutting likely facilitated adaptations to parasitize hosts hidden in hard substrates, which pose challenges to the emerging wasps. We reveal a crucial step in insect evolution and highlight the importance of comprehensive studies even of putatively well-known systems.

• Klíčová slova
• functional morphology, insect diversification, mandibles,
• MeSH
• fylogeneze MeSH
• fyziologická adaptace MeSH
• interakce hostitele a parazita MeSH
• sršňovití * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A study was conducted to determine whether the mandibles of the detrito-/bryophagous groundhopper Tetrix tenuicornis are subject to mechanical wear as a result of feeding, as is the case for grasshoppers that feed on silica-rich grasses. Abrasion was evaluated by measuring the length and width of the 3rd incisor and length of the 4th incisor in adults of different ages collected under natural conditions during one season. Although T. tenuicornis and other groundhoppers avoid feeding on grasses, we found that mandible abrasion increased with T. tenuicornis age. Age-related abrasion of the incisors of left and right mandibles was statistically significant in both sexes but the degree of abrasion was greater for females than males, apparently reflecting differences in the frequency and magnitude of feeding. Degree of abrasion also differed between right and left mandibles, probably because of differences in how each mandible is used during food processing. Abrasion of cuticular mandible structures may reduce the effectiveness of food processing late in the season.

• Klíčová slova
• Aging, Bryophagy, Detritophagy, Exoskeleton, Mechanical wear, Morphology,
• MeSH
• mandibula patologie   MeSH
• Orthoptera anatomie a histologie   fyziologie   MeSH
• sexuální faktory MeSH
• stárnutí * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• EXPERIMENTAL LAB STUDY *, FRACTURES *, MANDIBULAR INJURIES *, RADIATION INJURY, EXPERIMENTAL *, RATS *,
• MeSH
• experimentální radiační poranění * MeSH
• fraktury kostí * MeSH
• fraktury mandibuly * MeSH
• krysa rodu Rattus MeSH
• mandibula * MeSH
• poranění mandibuly * MeSH
• radiační poranění * MeSH
• výzkum * MeSH
• Check Tag
• krysa rodu Rattus MeSH
• Publikační typ
• časopisecké články MeSH

The Middle Pleistocene site at Bilzingsleben is being excavated by the Forschungsstelle Bilzingsleben, FSU Jena. It is a living floor with structures of settlement and a great number of Lower Palaeolithic cultural remains. So far, 28 human skull fragments have been discovered, which can be reconstructed into two individual skulls. Recently, the right mandible has also been discovered (Bilzingsleben E7). Morphological comparisons indicate that there is a great similarity to the mandibles of HI and BI of Sinanthropus. A strong likeness to Arago II and XIII was also discovered. There are various different archaic features which assign the Bilzingsleben mandible and the two skulls to the advanced Homo erectus.

• MeSH
• dějiny starověku MeSH
• Hominidae anatomie a histologie   MeSH
• lebka anatomie a histologie   MeSH
• lidé MeSH
• mandibula anatomie a histologie   MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• dějiny starověku MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Německo MeSH

According to many investigations, changes in mandibular morphology can occur synchronously with changes in the environment, and sexual dimorphism of the mandible can be influenced by the environment. Sexual dimorphism during the last 1200 years was evaluated using geometric morphometric analysis of virtual cranial models. The method of geometric morphometrics allows differences in size and shape to be assessed separately. We analyzed groups of adult individuals dating to Early Middle Ages, High Middle Ages, Early Modern Ages and from a modern Czech population (21st century). Significant sexual dimorphism in mandibular size was found in all populations. A trend in the sexual dimorphism of size was seen, with differences between the sexes increasing gradually over time. Size changes in female mandibles were a better reflection of environmental conditions and climate than size changes in male mandibles. Regarding changes in the sexual dimorphism of shape, significant dimorphism was found in all four samples. However, the pattern of mandibular shape dimorphism was different and varied considerably between samples. There was only one stable shape trait showing sexual dimorphism across all four samples in our study: the gonion lies more laterally in male than in female mandibles and male mandibles are relatively wider than female mandibles. Sexual dimorphism of shape is not influenced by the climate; instead sexual selection might play a role. This research supports earlier studies that have found that the degree and pattern of sexual dimorphism is population-specific and the factors regulating sexual dimorphism today may not be the same as those in the past.

• MeSH
• dějiny 15. století MeSH
• dějiny 16. století MeSH
• dějiny 17. století MeSH
• dějiny 18. století MeSH
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• dějiny středověku MeSH
• dieta MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mandibula anatomie a histologie   MeSH
• podnebí MeSH
• sexuální faktory * MeSH
• životní prostředí MeSH
• zkameněliny * MeSH
• Check Tag
• dějiny 15. století MeSH
• dějiny 16. století MeSH
• dějiny 17. století MeSH
• dějiny 18. století MeSH
• dějiny 19. století MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• dějiny středověku MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Evropa MeSH

• Klíčová slova
• JAW *,
• MeSH
• čelisti * MeSH
• fibrom * MeSH
• lidé MeSH
• mandibula * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH