The anadromous Rutilus kutum Kamenskii, 1901is the most important fish in north of Iran with the highest economic value. Ignoring the natural process of reproduction due artificial propagation, catching some migrating broodstocks from the sea (not from the estuaries) and mixing the produced fingerlings in culture ponds within restocking programs in the last 30 years have caused an uncertainty about homing success and population differentiation in the fish. A 13-landmark morphometric truss network system was used to investigate the hypothesis of homeward migration success and population differentiation, while the previous studies revealed low genetic variability among the fish populations. A total of 504 adult specimens were caught from four localities along the southern Caspian Sea in the reproductive period. Univariate analysis of variance showed significant differences among the four groups for 78 standardized morphometric measurements. In linear discriminant function analysis (DFA), the overall assignments of individuals into their original groups were 73.3 % and 80.3 % in males and females, respectively. The principal component analysis (PCA) and clustering analysis based on Euclidean square distances showed that the 504 examined specimens grouped into distinct areas. The results showed that each sampling site represents independent population which confirmed the success of homeward migration. The high grouping ranges suggests that almost all populations return to their birthplace river to breed, which results in high inbreeding. The results can be interesting for management and conservation programs of this valuable species in the Caspian Sea.
The thymus plays a critical role in establishing and maintaining the peripheral T-cell pool. It does so by providing a microenvironment within which T-cell precursors differentiate and undergo selection processes to create a functional population of major histocompatibility complex-restricted, self-tolerant T cells. These cells are central to adap tive immunity. Thymic T-cell development is influenced by loca lly produced soluble factors and cell-to-cell interactions, as well as by sympathetic noradrenergic and endocrine system signalling. Thymic lymphoid and non- lymphoid cells have been shown not only to express β - and α 1 - adrenoceptors (ARs), but also to synthesize catecholamines (CAs). Thus, it is suggested that CAs influence T-cell development via both neurocrine/endocrine and autocrine/ paracrine action, and that they serve as immunotransmitters between thymocytes and nerves. CAs acting at multiple sites along the thymocyte developmental route affect T-cell generation not only numerically, but also qualitatively. Thymic CA level and synthesis, as well as AR expression exhibit sex steroid-mediated sexual dimorphism. Moreover, the influence of CAs on T-cell development exhibits glucocorticoid-dependent plasticity. This review summarizes recent findings in this field and our current understanding of complex and multifaceted neuroendocrine- immune communications at thymic level., G. Leposavić, I. Pilipović, M. Perišić., and Obsahuje bibliografii a bibliografické odkazy
The craniometrical analysis of population diversity of the Balkan chamois (
Rupicapra rupicapra balcanica) from Bulgaria was carried out using 14 skull parameters and 65 adult individuals, originating from the main occurrence areas in the country – Stara Planina, Rhodope, Rila and Pirin Mountains. The data showed a high degree of sexual dimorphism of the skull. The univariate and multivariate statistical assessment of the skull features of Bulgarian chamois, performed separately by gender, demonstrated a high degree of phenotypic craniological similarity between the specimens of the same gender from the four main populations in Bulgaria; it also supported the hypothesis that the present segregation of Bulgarian chamois into the four main mountains characterized by distinctive orographic features did not give rise to measurable levels of their craniometric differentiation.
Very little is known about the spawning behaviour of loach fishes, despite the fact that reproduction is one of the most important aspects in the autecology of animals. Here the spawning behaviour of golden spined loaches of the genus Sabanejewia is described for the first time. In opposite to spined loaches of the genera Cobitis and Misgurnus, the spawning partners do some ‘circle swimming’ together prior to spawning and the male does not form a full ring around the female but catches the female with a ‘V’-shaped body. This spawning behaviour explains why males of Sabanejewia, unlike nearly all other genera of Cobitidae, 1) are not significantly smaller than females, a condition that is required only to form a complete ring around the female,and 2) have swellings in the middle of the body instead of specialised rays of the pectoral fins like in most other genera. These swellings are in the part of the body that touches the female during the release of gametes, while the pectoral fins do not reach to female’s body.
Animals’ body size varies intra-specifically and geographically among populations, and many species (including small carnivores) show sexual dimorphism and larger individuals (lower superficial area/volume ratio) inhabiting cooler climates complying with Bergman’s rule. In the present study we analyse data of common genets wild-caught in three different regions of the Iberian Peninsula, searching for variations in size and weight between males and females, testing for sexual dimorphism, as well as for micro-scale geographical variations among populations in biometrics and sexual dimorphism. We use field measurements such as length (body and tail) and weight, to characterise the three populations in the Iberian Peninsula. Our results show that Iberian genets present significant differences between sexes, although sexual dimorphism is lower than in other small carnivores, and that they comply with Rensch’s rule, males size showing greater variation. Iberian genets also follow the Bergman’s rule, being bigger and heavier in colder and northern regions. Although we have detected morphometric differences among studied populations, sexual dimorphism indexes varied little. We discuss our results in the light of the different hypotheses given to explain the sexual dimorphism in carnivores, trying to identify the mechanisms that might play a role in the dimorphism of genets.
The Asiatic ibex is a threatened endemic species that is distributed in the mountains of central and northern Asia. Using the method of group scan sampling, the behaviour of the Asiatic ibex was studied in the autumn of 2005. The effects of group size and sex on vigilance were tested. The results indicated that both group size and sex affected vigilance levels. Male ibex were significantly more vigilant than females at both the group scan level (percentage of individuals scanned during a session) and group scan frequency (percentage of intervals with at least one individual scanning). The group scan level was negatively correlated with group size, and group scan frequency was positively correlated with the group size in male, female, and overall groups. These results showed that group size and sex affected vigilance in Asiatic ibex.
The New World genus Lepidosina Marshall & Buck gen. n. is described including nine new and two previously described species: L. angusticercus Marshall & Buck sp. n. (Caribbean, Central and South America), L. argentinensis Marshall & Buck sp. n. (Argentina), L. cubensis Marshall & Buck sp. n. (Cuba), L. evanescens Marshall & Buck sp. n. (Central and South America), L. gibba (Spuler) comb. n. (Florida, Caribbean), L. inaequalis (Malloch) comb. n. (southern U.S.A., Central America, Venezuela), L. multispinulosa Marshall & Buck sp. n. (Ecuador, Peru), L. platessa Marshall & Buck sp. n. (Bolivia), L. proxineura Marshall & Buck sp. n. (Brazil), L. quadrisquamosa Marshall & Buck sp. n. (Venezuela), and L. rutricauda Marshall & Buck sp. n. (Colombia to Peru). Keys to males and females are provided, and the species level phylogeny is analyzed based on a matrix of 24 morphological characters. The sister group of this well-defined, highly apomorphic genus remains unknown. Most species are restricted to lowland habitats. Larvae and puparia of Lepidosina remain unknown.
Adjacivena rasnitsyni gen. n., sp. n., from the Middle Jurassic Jiulongshan Formation (Daohugou Village, Inner Mongolia,
China), is described based on a set of well-preserved specimens, interpreted as two females and a male of the same species. The new
taxon is assigned to the family Susumaniidae, i.e. is a candidate stem-Phasmatodea. This ordinal assignment is supported by genital
elements, chiefly a putative operculum concealing the ovipositor observed in one female specimen and a putative extension of the
10th tergum with a thorn pad in the male specimen. Variation in the venation of the forewing is appreciated based on more or less
complete pairs of wings and a comparison with that in the forewings of male Heteropteryx dilatata (Parkinson, 1798). This material
offers new perspectives on the primary homologies of the hind wing venation of stick-insects.
Unfed nymphs of Ixodes ricinus (L.) can be divided into two morphological groups according to the length of idioso-ma, scutum, hypostome and palpal segment III, and the number of dorsal alloscutal setae. Specimens of greater body dimensions and more numerous dorsal alloscutal setae moulted predominantly into females. The frequency of different nymphal length categories in field-collected ticks followed a normal distribution. The length of unfed nymphs correlates well with the length (r = 0.7248 ± 0.0711, P < 0.001) and weight (r = 0.6519 ± 0.0782, P < 0.001) of engorged nymphs, however, it varies in ticks of different origin. In field-collected ticks, freshly engorged female nymphs were 2.30-2.94 mm long, male nymphs 2.14-2.46 mm long. Feeding period (P < 0.05) and premoulting period (P < 0,001 ) were significantly longer in female nymphs both in field-collected and laboratory-derived I. ricinus. The engorgement weight was found to be the best criterion for differentiation of male and female nymphs of ixodid ticks. In field-collected nymphs engorged on BALB/c mice, 98.6 % of females moulted from nymphs weighting more than 3.60 mg, while in laboratory-derived ticks, 98.4 % of females emerged from nymphs of 3.42 mg body mass or more.
The present study provides a comprehensive osteological description of Pachypterus khavalchor from the family Horabagridae. Nine individuals of P. khavalchor representing both males and females collected from the type locality were cleared and double-stained to provide a description of osteological characteristics. The presence of an almost straight dorsal roof to the cranium, a long and protruding premaxilla with numerous rows of tiny, villiform teeth, a spoon-like lower jaw with villiform teeth projecting outward, and five long and ossified ceratobranchials, with the 5th ceratobranchial containing a set of 80 to 90 conical teeth, sheds light on the ecomorphological adaptation in P. khavalchor that may have led to the evolution of lepidophagy. Furthermore, a slight difference in the structure of the complex hypurapophysis was observed between males and females. The information on the osteology of the Khavalchor catfish forms a baseline for taxonomic research of the entire Horabagridae family comprising four genera with ten species distributed in Asia.