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2. Karyotype diversity of the offspring resulting from reproduction experiment between diploid male and triploid female of silver Prussian carp, Carassius gibelio (Cyprinidae, Actinopterygii)

Creator:
Kalous, Lukáš and Knytl, Martin
Type:
article and TEXT
Subject:
cytogenetic, chromosome number, ploidy level, and hybriditazion
Language:
English
Description:
Populations of silver Prussian carp (Carassius gibelio) are known to exhibit different ploidy levels among their individuals. No consistent information is available regarding chromosome number of triploid biotype. Generally diploids have 100 chromosomes while triploids have 150-160 chromosomes. The karyotype of the C. gibelio triploid biotype is characterized by a variable number of small chromosomal elements called supernumerary chromosomes. Here we report the results of a reproduction experiment between a diploid male and triploid female with respect to chromosome numbers of the parents and their offspring. Thirty metaphases of both parents and fifteen individuals of the offspring were investigated. We found variability in chromosome numbers among analysed offspring with a fluctuation from 150 to 159. In comparison, the chromosome numbers of male and female individuals were found to be 100 and 159 respectively. Our results show a high chromosomal plasticity of the Carassius gibelio triploid biotype.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

3. Loaches and the environment in two provinces in Norhern Vietnam

Creator:
Petrtýl, Miloslav, Bohlen, Jörg, Kalous, Lukáš, The Bui, Anh, and Chaloupková, Petra
Type:
article and TEXT
Subject:
biodiversity, the River Pearl, Schistura, Leptobotia, Tracccatichthys, Cobitis, and Misgurnus
Language:
English
Description:
During the last decades, agriculture activities in the mountainous northern provinces of Vietnam intensified drastically, and today rice fields occupy the complete valleys of local streams and rivers. Upstream of the fields, many dams were built mainly for irrigation purposes; sometimes stopping the flow through the lower courses of the creek completely. Illegal fishing with electro-fishing gears is a common way to improve food supply for local villagers. Larger rivers are impacted by non-selective fishing, gravel mining and pollution. These factors represent threats to the local fish communities, which typically include one or several species of loaches.With usage of electro-fishing gear and hand net we surveyed 16 localities of the river basins of the River Ky Cung and the River Bang Giang. Both rivers belong to the drainage area of the River Pearl in the provinces Lang Son and Cao Bang in Northern Vietnam. We focused on getting maximum number of fish species with special attention to loaches at each locality. Ten species of loaches were found; at least two of them represent undescribed species. The main conclusion is that the ichthyofauna of Northern Vietnam still holds a hidden diversity, but at the same time is under strong anthropogenic pressure, so that parts of the diversity may be lost soon.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

4. Osteological description of Indian lepidophagous catfish Pachypterus khavalchor (Siluriformes: Horabagridae) from the Western Ghats of India

Creator:
Pise, Manoj, Gosavi, Sachin M., Gorule, Pankaj A., Verma, Chandani R., Kharat, Sanjay S., Kalous, Lukáš, and Kumkar, Pradeep
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
skeletal morphology, lepidophagy, sexual dimorphism, and systematics
Language:
English
Description:
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.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public