Joerg Bohlen

• Doctor of Philosophy
• Czech Academy of Sciences, Institute of Animal Physiology and Genetics

Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive, larg...

Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic era, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive,...

Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic era, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive,...

Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic era, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive,...

Eurasia has undergone substantial tectonic, geological, and climatic changes throughout the Cenozoic era, primarily associated with tectonic plate collisions and a global cooling trend. The evolution of present-day biodiversity unfolded in this dynamic environment, characterised by intricate interactions of abiotic factors. However, comprehensive,...

Asexual reproduction can be triggered by interspecific hybridization, but its emergence is supposedly rare, relying on exceptional combinations of suitable genomes. To examine how genomic and karyotype divergence between parental lineages affect the incidence of asexual gametogenesis, we experimentally hybridized fishes (Cobitidae) across a broad p...

To approach the taxonomy of large and complex animal groups it is of advantage to focus on species groups with shared derived character state. We investigate the composition, morphological characteristics and relationships of and within the Schistura cincticauda species group, whose members are small freshwater fishes that inhabit streams and river...

Asexual reproduction can be triggered by interspecific hybridization, but its emergence is supposedly rare, relying on exceptional combinations of suitable genomes. To examine how genomic and karyotype divergence between parental lineages affect the incidence of asexual gametogenesis, we experimentally hybridized fishes (Cobitidae) across a broad p...

The karyotype of the freshwater fish Sabanejewia bulgarica (Drensky, 1928), from the Danube Delta, was studied by conventional Giemsa staining and the C-banding technique. The diploid chromosome number was 2n = 50. The karyotype contained 2 pairs of metacentric (the first one was much larger than the second one), 6 pairs of submetacentric and 17 pa...

Asexual reproduction can be triggered by interspecific hybridization, but its emergence is supposedly rare, relying on exceptional combinations of suitable genomes. To examine how genomic and karyotype divergence between parental lineages affect the incidence of asexual gametogenesis, we experimentally hybridized fishes (Cobitidae) across a broad p...

Asexual reproduction can be triggered by interspecific hybridization, but its emergence is supposedly rare, relying on exceptional combinations of suitable genomes. To examine how genomic and karyotype divergence between parental lineages affect the incidence of asexual gametogenesis, we experimentally hybridized fishes (Cobitidae) across a broad p...

As whole‐genome sequencing has become pervasive, some have suggested that reduced genomic representation approaches, for example, sequence capture, are becoming obsolete. In the present study, we argue that these techniques still provide excellent tools in terms of price and quality of data as well as in their ability to provide markers with specif...

Asexual reproduction can be triggered by interspecific hybridization, but its emergence is supposedly rare, relying on exceptional combinations of suitable genomes. To examine how genomic and karyotype divergence between parental lineages affect the incidence of asexual gametogenesis, we experimentally hybridized fishes (Cobitidae) across a broad p...

Nemacheilus cacao, new species, is described from the middle Mekong basin in Laos. It differs from all other species of Nemacheilus by having an incomplete lateral line; and adult males having a plain grey-brown body and head (except ventral side), and with extensive tuberculation on the flank, on the dorsal side of the pectoral fin and on the head...

Homomorphic sex chromosomes and their turnover are common in teleosts. We investigated the evolution of nascent sex chromosomes in several populations of two sister species of African annual killifishes, Nothobranchius furzeri and N. kadleci, focusing on their under-studied repetitive landscape. We combined bioinformatic analyses of the repeatome w...

Paracanthocobitis epimekes, new species, is described from the Tenasserim and Lenya river basins in Tanintharyi Province, Myanmar, and the Takua Pa River basin in Phang Nga Province, Thailand. Paracanthocobitis epimekes is genetically the sister species of all other species in the P. zonalternans species group and co-occurs with P. phuketensis in m...

Repetitive DNA represents an important driver of sex chromosome differentiation. Yet, repetitive sequences tend to be misrepresented or overlooked in genomic studies. We analysed repetitive DNA landscape of sex chromosomes in several populations of a turquoise killifish Nothobranchius furzeri and its sister species N. kadleci (Teleostei: Nothobranc...

Simple Summary Since large animal families with unresolved taxonomy are difficult to study, it is better to focus on smaller units. In the present study, we test if we can define a restricted group of species within a large and unsorted fish family (Nemacheilidae). In the beginning, we selected 17 candidate species that share a rare and specific pi...

Tanichthys albiventris, new species, from the River Jiangping in Dongxing City, Guangxi Province is distinguished from Tanichthys albonubes by the presence of a reddish-orange dorsal-fin margin (vs. white) and 9-10 (9 in mode) branched anal-fin rays (vs. 8 in mode). Tanichthys flavianalis, new species, from the River Jiuqu in Qionghai City, Hainan...

Freshwater fishes of the superfamily Cobitoidea are a species-rich group that are present in virtually every river in Europe and Asia. Three of the nine recognized families show massive karyotype reconstructions, including several independent cases of polyploidy, indicating cytogenetic evolution correlated with their diversification. We herein pres...

Sex chromosomes are generally derived from a pair of classical type-A chromosomes, and relatively few alternative models have been proposed up to now.¹,² B chromosomes (Bs) are supernumerary and dispensable chromosomes with non-Mendelian inheritance found in many plant and animal species³,⁴ that have often been considered as selfish genetic element...

Southeast Asia is one of the world’s biodiversity hotspots, and the high level of diversity and endemism was reached by colonisation events as well as internal diversification. We investigate the phylogenetic relationships and biogeographic history of the loach genus Nemacheilus, which is widely distributed and common across freshwaters of Southeas...

The Schistura robertsi species complex is a group of freshwater fish inhabiting streams in southeast Myanmar as well as in western and southern Thailand. In southern Thailand, the distribution exceeds the biogeographically important ‘Surat Thani – Krabi line’. The complex is believed to include five described and one undescribed species, but monoph...

Western Southeast Asia is hosting one of the world’s most diverse faunas, and one of the reasons for this huge diversity is the complex geologic past of the area, increasing the frequency of isolation and expansion events over evolutionary time scale. As an example case, the present study reveals the phylogeny and biogeographic history of the Parac...

Phylogenetically, the family Cobitidae consists of an assemblage of lineages that are referred to as ‘southern lineages’, out of which stems a monophyletic bunch of lineages that is referred to as ‘Northern clade’. Up to now, 17 of the 21 valid genera have been included into genetic phylogenies. The present phylogenetic study analyses the only two...

Tanichthys kuehnei, new species, is described from a stream in the Bach Ma Mountains in Hue Province in Central Vietnam. The new species differs from its congeners by having more branched rays in anal fin (9 1 / 2 vs. 7-8 1 / 2 in T. micagemmae and 8 1 / 2 in T. albonubes and T. thacbaensis). Morphological and genetic characters suggest it to be cl...

The karyotype of Greek cobitid fish Cobitisstrumicae Karaman, 1955, from Lake Volvi, Greece, a representative of one of its two major intraspecific phylogenetic lineages, was analysed by means of sequential Giemsa-staining, C-banding, silver-staining, CMA 3 fluorescence banding and also by in situ hybridization (FISH) with rDNA probe. The diploid c...

Polyploidization has played an important role in the evolution of vertebrates, particularly at the base of Teleostei–an enormously successful ray-finned fish group with additional genome doublings on lower taxonomic levels. The investigation of post-polyploid genome dynamics might provide important clues about the evolution and ecology of respectiv...

FISH with 5S rDNA and U2 snDNA probes in the rest of examined botiid species. U2 snDNA (red, arrows) and 5S rDNA (green, arrowheads) probes (B,F,H) or a single U2 snDNA (red, arrows) probe (A,C,D,E,G) mapped on (A) B. almorhae, (B) Ch. macracanthus, (C) L. elongata, (D) L. guilinensis, (E) P. fasciatus, (F) S. pulchra, (G) S. superciliaris, (H) S....

PNA FISH with telomeric probe in the rest of examined botiid species. (A) B. udomritthiruji, (B) S. pulchra, (C) S. superciliaris, (D) S. zebra, (E) Y. lecontei. For better contrast, pictures were pseudocoloured in green (telomeric repeat probe) and red (DAPI). For better distinction between individual chromosomes, we included also the separate ima...

Selected sequential experiments clarifying conjugated or independent location of distinct cytogenetic markers. Metaphases are arranged sequentially in Ch. macracanthus (A,D), L. elongata (B,E), L. guilinensis (C,F), L. microphthalma (G,I) and S. superciliaris (H,J) after CMA3/DAPI staining (D,E,F,I,J) and corresponding dual-colour FISH with 28S rDN...

Karyotype and mitotic chromosomes of B. dario after different cytogenetic protocols. (A) Karyotype arranged from Giemsa-stained chromosomes, (B) CMA3/DAPI staining. (C) Dual-colour FISH with 28S rDNA (red, arrows) and 5S rDNA (green, arrowheads) probes. (D) Uni-colour FISH with U2 snDNA (red, arrows) probe. (E) PNA FISH with telomeric probe. Due to...

CMA3/DAPI staining in the rest of examined botiid species. (A) B. udomritthiruji, (B) L. elongata, (C) P. fasciatus, (D) S. superciliaris, (E) S. zebra, (F) Y. lecontei. For better contrast, pictures were pseudocoloured in red (for CMA3) and green (for DAPI). Open arrows indicate CMA3-positive sites. The metaphase spread of S. superciliaris (D) is...

Dual-colour (5S/45S) rDNA FISH in the rest of examined botiid species. 28S rDNA (red, arrows) and 5S rDNA (green, arrowheads) probes mapped on (A) L. elongata, (B) L. microphthalma, (C) S. superciliaris, (D) S. zebra, (E) Y. lecontei. Chromosomes were counterstained with DAPI (blue). Note the significant spreading of 5S rDNA sites in Y. lecontei (E...

Leptobotia micra, new species, is described from the upper Li River (Pearl River basin) around Guilin in Guangxi province, southern China. The new species is evidently the smallest species of Leptobotia, with females of 45‒46 mm SL bearing oocytes. It can be distinguished from all other species of Leptobotia by a combination of the following charac...

Here, we present the first complete mitochondrial genome of the Red Tailed Loach Yasuhikotakia modesta (Teleostei: Botiidae) from Thailand, assembled from next-generation transcriptome sequencing data. The assembled transcript corresponds to the full length mitochondrial genome of Y. modesta, which measured 16,865 bp in length, and contained 13 pro...

A new species, Leptobotia bellacauda is described from the lower Yangtze River basin. The new species is distinguished from all other species of Leptobotia by a combination of the following characters: body plain brown, prominent black bar in caudal fin, dorsal half of head dusky black, ventral half of head cream colour, eye well developed, lobes o...

One of the most efficient mechanisms to keep animal lineages separate is a difference in ploidy level (number of whole genome copies), since hybrid offspring from parents with different ploidy level are functionally sterile. In the freshwater fish family Botiidae, ploidy difference has been held responsible for the separation of its two subfamilies...

Schistura kampucheensis, new species, is described from several localities in Cambodia. It is distinguished from all other species of Schistura by a combination of the following characters: 6-11 more or less regular, continuous black bars on body, reaching ventrally usually to level of pectoral fins; no black midlateral stripe; 8 1 /2 branched dors...

We present a phylogenetic investigation of the Northern Clade, the major monophyletic clade within the freshwater fish family Cobitidae, one of the most prominent families of freshwater fishes found in Asian and European waters. Phylogenetic reconstructions based on the cytochrome b and RAG-1 genes show the genera Microcobitis, Sabanejewia, Koreoco...

Species identifications after [29]. Listed are the IDs for individuals as referred to in the corresponding listed reference, localities and accession numbers for the cyt b and RAG-1 sequences used in phylogenetic analyses. Country code abbreviations according to ISO alpha-2. (DOC)

Background: Loaches of the family Nemacheilidae are one of the most speciose elements of Palearctic freshwater ichthyofauna and have undergone rapid ecological adaptations and colonizations. Their cytotaxonomy is largely unexplored; with the impact of cytogenetical changes on this evolutionary diversification still unknown. An extensive cytogeneti...

One of the most efficient mechanisms to keep animal lineages separate is a difference in ploidy level, since hybrid offspring from parents with different ploidy level are generally sterile. In the freshwater fish family Botiidae, ploidy difference has been held responsible for the separation of its two subfamilies, the tetraploid Botiinae and the d...

Incomplete knowledge of biodiversity remains a stumbling block for conservation planning, and even occurs within globally important Biodiversity Hotspots. Although technical advances have boosted the power of molecular biodiversity assessments, the link between DNA sequences and species and the analytics to discriminate entities, remain crucial. He...

Schistura shuensis, new species, is described from Shu stream on the eastern slope of the Rakhine range in Myanmar. It reaches up to 39.1 mm SL and is diagnosed by a combination of the following characters: males with suborbital flap, bearing tubercles on its posterior part, females with suborbital groove; caudal fin deeply forked (mean length of m...

Schistura hypsiura, a new species, is described from the western slope of the Rakhine Yoma, Myanmar. It is distinguished from all congeners by having a very deep caudal peduncle without dorsal and ventral skin crests, a deeply forked caudal fi n, a suborbital fl ap in adult males, and a well-developed suborbital groove in adult females.

Schistura hypsiura, a new species, is described from the western slope of the Rakhine Yoma, Myanmar. It is distinguished from all congeners by having a very deep caudal peduncle without dorsal and ventral skin crests, a deeply forked caudal fi n, a suborbital fl ap in adult males, and a well-developed suborbital groove in adult females.

Schistura puncticeps, new species, is described from the Nam Paw stream, Shan State, Myanmar. It is distinguished from all other species of Schistura by a combination of the following characters: head dorsally and laterally covered by dark brown dots, 5-8 large dark brown blotches along lateral midline of the body; a large head (head length 20.7-24...

Schistura rubrimaculata, new species, is described from two streams on the eastern slope of the Rakhine Range draining in Irrawaddy River. It reaches up to 27.7 mm SL and differs from all other species of Schistura by the presence of a distinct red dot above the midlateral line before the caudal-fin base (not visible in preserved specimens), a very...

Sympatric species pairs are particularly common in freshwater fishes associated with postglacial lakes in northern temperate environments. The nature of divergences between co-occurring sympatric species, factors contributing to reproductive isolation and modes of genome evolution is a much debated topic in evolutionary biology addressed by various...

In this study, records on the occurrence of the Japanese ginbuna Carassius langsdorfii from northern Germany, north-western Italy and southern Bosnia and Herzegovina are presented. The new findings, in addition to former studies reported in the Czech Republic and Greece, show that C. langsdorfii is much more widespread in Europe than was previously...

Because most clonal vertebrates have hybrid genomic constitutions, tight linkages are assumed among hybridization, clonality, and polyploidy. However, predictions about how these processes mechanistically relate during the switch from sexual to clonal reproduction have not been validated. Therefore, we performed a crossing experiment to test the hy...

A phylogeny of the genus Carassius using the mitochondrial cytochrome b gene supported the monophyly and distinctness of the species C. carassius, C. auratus, C. langsdorfii and C. cuvieri. In contrast, the samples of C. gibelio did not form a monophyletic lineage, but separated into two clades, suggesting the inclusion of two species under the nam...

The freshwater characiform fsh Prochilodus lineatus is a detritivorous species that has its native distribution area in South America but has been imported to China for aquaculture purposes. This is the frst time that it is being reported in Vietnam, both from aquaculture and captured from a river channel. According to local authorities, the specie...

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 comp...

Nemacheilus paucimaculatus, a new species of loach, is described from three localities in the southern Malay Peninsula. It is distinguished from all congeners except N. arenicolus by its colour pattern of 8-10 dark brown dorsal saddles and 8–10 dark brown blotches, each larger than eye, along the lateral midline. It is distinguished from N. arenico...