Karyomorphometric analysis of somatic chromosomes of selected seagrasses of families Hydrocharitaceae and Cymodoceaceae

• Chromosome numbers of elevenseagrass species were determined.
• Karyomorphology was mapped for 10 species.
• Karyotypic formula varies among seagrass species and can be a tool for taxonomic confirmation.

Chromosome numbers of eleven seagrass species were determined. The highest chromosome number was recorded in Halodule spp. (2n = 44) and the lowest chromosome number was observed in Cymodocea rotundata (2n = 14). Chromosome numbers were identical or closely related among different species in the same genus. Karyomorphology was mapped for nine species (Halodule pinifolia, Halodule uninervis, Halodule wrightii, Syringodium isoetifolium, Enhalus acoroides, Halophila beccarii, Halophila ovalis (subsp. ovalis and ramamurthiana) Halophila ovata and Thalassia hemprichii). Length of the chromosomes of these species varied from 7.81 to 336.63 μm while the fundamental arm number ranged between 36 and 85. The results confirm the karyotypic variation among the studied species, indicating that this characteristic can be used to confirm taxonomic identity of species which are morphologically very similar (eg. Halodule spp.). All tested species were diploid, except for Cymodocea rotundata.