Farlowella schreitmuelleri Arnold, 1936

Marajó, Leandro, Viana, Patrik F., Ferreira, Milena, Rapp Py-Daniel, Lúcia H. & Feldberg, Eliana, 2018, Cytogenetics of two Farlowella species (Loricariidae: Loricariinae): implications on the taxonomic status of the species, Neotropical Ichthyology 16 (4), pp. 1-8 : 2-3

Farlowella schreitmuelleri Arnold, 1936 .

Farlowella schreitmuelleri also had a diploid chromosome number 58 and karyotype composed of 10m + 30m +14st+4a, and FN = 112 ( Fig. 1d ). A secondary constriction was observed in the distal region of the long arms of the acrocentric pair No. 28, together with size heteromorphism, corresponding to the Ag-NOR ( Fig. 1f ), the ribosomal 18S DNA ( Fig. 2e ), and positive C-banding sites.

The genome of this species possessed a much larger quantity of heterochromatin compared to Farlowella cf. amazonum , located in the centromeric region of all chromosomes, where some bands were more conspicuous than others. Interstitial bands also occurred in the long arms of pairs Nos. 7, 9, 14, 22, and 23. Pairs Nos.8, 24, 25, and 28 also had conspicuous bands in the terminal region of the long arms ( Fig. 1e ).

Multiple 5S rDNA sites were observed, in sm pair No. 16 (in only one of the homologs) and st pair No. 26. Both these sites were positive for C-banding ( Fig. 2f ). Hybridiza- tion with telomeric probes revealed terminal signals in all chromosomes and Interstitial Telomeric Sequences (ITSs) in pairs Nos. 7, 14, 25, and 28, all of which corresponded with heterochromatin blocks. In pair No. 28, the ITS was observed in only one of the homologs ( Fig. 2b ).

Figures

Fig. 1. Karyotype of Farlowella cf. amazonum: (a) Giemsa staining, (b) C-banding, and (c) NORs (highlighted). Karyotype of Farlowella schreitmuelleri: (d) Giemsa staining, (e) C-banding, and (f) NORs (highlighted). Scale bar = 10 µm.

Fig. 2. Karyotype of Farlowella cf. amazonum: (a) telomeric sequences, (c) 18S rDNA, and (d) 5S rDNA. Karyotype of Farlowella schreitmuelleri: (b) telomeric sequences, (e) 18S rDNA, and (f) 5S rDNA. Scale bar = 10 µm.