Data on chromosomal polymorphism in two natural populations from the Inya River in Western Siberia (Novosibirsk province) of Chironomus sp. J (Kiknadze, 1991) —one of the sibling species from the Chironomusplumosus group — are presented for the first time. The species belongs to the “thummi” cytocomplex with 2n = 8 and the arm’s combination AB CD EF G and is closely related to Ch.nudiventris Ryser, Scholl et Wülker, 1983, which has 2n = 6 with the arm’s combination AB CD GEF (a modified “thummi” cytocomplex). The main difference between these two species is the number of chromosomes, apart from that they only differ by the frequencies of banding sequences in arm A, and the presence or absence of some polymorphic inversions. The banding sequence pool of Chironomus sp. J consists of 15 banding sequences. Inversions were found in five chromosomal arms – A, B, D, E, F. The most polymorphic arms were B and D. Two studied populations differed by the level of chromosomal polymorphism with one population being completely monomorphic and the other showing high level of polymorphism with 62–65% of heterozygotes and 0.83–0.88 heterozygotic inversion per larva (depending on the year of collection). Comparison of banding sequences to other species from the group showed that Chironomus sp. J is indeed closest to Ch.nudiventris, with the cytogenetic distance of 0.058 or 0.471 depending on the method of calculation, which indicates that these two species are very closely related. The relationship between Chironomus sp. J and other species from the Ch.plumosus group was discussed.

Bothriurus Peters, 1861 is one of the most diverse genera within the family Bothriuridae. However, to date, only five species have been analyzed using a cytogenetic approach. In this study, for the first time, two populations of Bothriurusasper Pocock, 1893 and nine populations of Bothriurusrochai Mello-Leitão, 1932, two species from northeastern Brazil, were analyzed with respect to diploid number, chromosomal behavior during meiosis, and the localization of heterochromatin and nucleolus organizer regions (NORs). For B.asper, a diploid number of 2n = 30 was recorded in geographically distant populations, whereas B.rochai exhibited intraspecific variation in diploid number (2n = 16 and 2n = 18), representing the lowest diploid numbers ever reported for the family Bothriuridae. Despite the variability in diploid number, the number and localization of NORs remained stable among the populations of B.rochai. When comparing heterochromatin patterns between the two species, larger blocks of constitutive heterochromatin were observed in B.asper than in B.rochai. Variation in the amount of heterochromatin among populations of B.rochai was also observed; in this case, the population with the lowest amount of heterochromatin also exhibited the greatest variation in post-pachytene cell configurations. This is the first study to cytogenetically analyze multiple populations of species within the genus Bothriurus, and it significantly expands the karyotypic information available for scorpions with monocentric chromosomes.

The anuran species group Physalaemusgracilis comprises six species, and variation in the location of nucleolus organizer regions (NORs) was observed across the four species that have been karyotyped to date. The NORs are located interstitially on chromosome 8 of P.carrizorum Cardozo et Pereyra, 2018, and P.lisei Braun et Braun, 1977, terminally on chromosome 8 of P.gracilis (Boulenger, 1883), and terminally on chromosome 10 of P.barrioi Bokermann, 1967. To contribute to the comparative analysis of this group, including the assessment of the hypothesis of homology among these NOR-bearing chromosomes, we described the karyotype of P.evangelistai Bokermann, 1967, and expanded the cytogenetic analyses of P.carrizorum, P.lisei, and P.barrioi. We used classical cytogenetic techniques and mapped, by fluorescent in situ hybridization (FISH), two repetitive sequences: the PcP190 satellite DNA and the U2 snRNA gene. Physalaemusevangelistai exhibited a 2n = 22 karyotype, with meta- and submetacentric chromosomes, which corresponds to the typical karyotypic configuration of the genus. We found an interstitial heterochromatin DAPI-positive band on the short arm of the NOR-bearing chromosomes 8 of P.evangelistai and P.carrizorum from Palmas-PR, and chromosome 10 of P.barrioi, which corroborates the hypothesis that these chromosomes are homologous. In P.evangelistai, an additional NOR was observed on chromosome 9 of females. Moreover, the karyotype of P.carrizorum from Palmas-PR differed from that previously described for P.carrizorum from Misiones, particularly in the number of PcP190 clusters and intrachromosomal position of the NOR on chromosome 8. Specimens from Palmas-PR showed a terminal NOR on chromosome 8 and PcP190 clusters on chromosomes 1 and 3, whereas those from Misiones had an interstitial/pericentromeric NOR on chromosome 8 and a single PcP190 cluster on chromosome 3. Further analyses are still needed to assess whether these cytogenetic differences represent interspecific variation.

Checking old unphotographed slides of chromosome preparations in the possession of R.B.A. revealed one slide labelled “frater ♀7g 6/6/13 ✓”. The beetle with these data is a female paratype of H.aquila Angus et al., in the general collection of the Natural History Museum, London. One almost complete dividing nucleus was found, with 32 chromosomes, indicating a triploid nucleus with one chromosome lost in the course of preparation of the slide.

The chromosome number of Hynobiusfucus was found by Lai and Lue (2008) to be 2n = 58, displaying a karyomorph similar to those previously reported in stream-type salamanders from Taiwan. Based not only on cytogenetic features but also on developmental characteristics such as the embryonic stage and the presence of interdigital membranes during limb formation this species can be confidently classified as a lotic stream-type salamander. Morescalchi (1975) proposed that karyotype evolution in families of urodeles tends to proceed from higher to lower chromosome numbers. Our findings from Taiwan suggest karyotype evolution within the genus Hynobius, that is, the chromosome number of this species may have increased from 2n = 56 in the pond-type ancestor to 2n = 58 in this stream-type lineage.

Scleractinian (stony) corals are foundational to reef ecosystems, yet their taxonomy remains unresolved due to morphological plasticity and limited cytogenetic data. This study presents the first molecular cytogenetic characterization of the scleractinian coral Micromussaamakusensis (Veron, 1990), employing fluorescence in situ hybridization (FISH) to isolate and map five DNA markers. Using the conventional Giemsa staining technique, M.amakusensis was found to have a diploid karyotype of 2n = 28, with a prominent homogeneously staining region (HSR) on the long arm of chromosome 12. Subsequently, five FISH markers designated as MA-H3 for histone H3, MA-5S for 5S rRNA, MA-18/28S for 18S-28S rRNA, MA-13C for centromeric region, and MA-TEL for telomeric region were cloned, sequenced, and mapped using FISH. FISH analysis revealed that the MA-H3 localized to the centromeric region of chromosome 1, MA-5S to the telomeric region of chromosome 4, MA-18/28S to the terminal region of chromosome 12 (coinciding with the HSR), MA-13C to the centromere of chromosome 13, and MA-TEL to multiple telomeric regions across several chromosomes. Sequence analysis confirmed marker identities and revealed conserved and novel repetitive elements. Furthermore, Genomic DNA hybridization (GDH) of whole-sperm DNA revealed signals collected at several telomeric regions, suggesting the presence of repetitive sequences. These cytogenetic markers enable the identification of at least 3 out of 14 chromosome pairs, allow for more precise karyotyping, and highlight chromosomal features that may help resolve coral classification and improve understanding of genome evolution. This research demonstrates the utility of molecular cytogenetics in stony coral systematics and provides new FISH markers for future comparative genomic studies.

[This corrects the article DOI: 10.3897/compcytogen.v16.i2.79033.].

Triploid female Helophorusbrevipalpis Bedel, 1881 are recorded from two localities in Provence, France. Their karyotypes are analysed using both chromosome morphology and C-banding. Their karyotypes appear to be identical with those of Spanish material recorded by Angus (1992) but show minor differences from Italian triploid material described by Angus, Jia (2020). Data on C-banding in English H.brevipalpis are given and chromosomal variation in H.brevipalpis is discussed.

We report on the results of a chromosomal study of the big-eyed true bug Geocorisdispar Waga, 1839 (Heteroptera: Geocoridae) aimed at obtaining data on its telomeres. Using fluorescence in situ hybridization (FISH), we have shown, that G.dispar has a non-canonical 10-bp telomeric motif TTAGGGGTGG. This is the first evidence of telomere structure in the family Geocoridae and the first finding of the telomeric sequence (TTAGGGGTGG)n in the large superfamily Lygaeoidea (infraorder Pentatomomorpha).

The African non-annual killifish genus Epiplatys Gill, 1862 (family Nothobranchiidae) comprises 36 valid species distributed in West, Central and East Africa. The available cytogenetic information for the genus indicates a wide variability in diploid chromosome number (2n) and number of chromosome arms (FN). Here, we report the karyotype of Epiplatysspilargyreius (Duméril, 1861), one of the two species with the lowest diploid chromosome number (2n = 34) in the genus, from the White Nile basin in Ethiopia. Male and female karyotypes contained 18 metacentric/acrocentric and 16 subtelocentric/acrocentric chromosomes. The number of chromosome arms is, respectively, FN = 52. Analysis of karyotype differentiation in the genus allowed us to suggest that the 2n reduction in E.spilargyreius and many other members of the genus Epiplatys is mainly due to Robertsonian translocations (reduction of 2n from 48 to 34 with stable NF = 48-52). We provide an up-to-date summary of cytogenetic data and a brief review of chromosome evolution in the genus.