Mesoplodon · 2n = 42
2n = 42
Beaked-whale genus Mesoplodon. Diploid karyotype 2n = 42 in the species these papers counted.
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Mesoplodon is one of the few cetacean genera with diploid number 2n = 42. Árnason 1978 counted 2n = 42 in M. europaeus and M. carlhubbsi. Kurihara et al. 2017 counted 2n = 42 in M. stejnegeri and M. carlhubbsi. Most Cetacea remain 2n = 44.
What it supports
Most whales a book will show you have 44 chromosomes. These do not. The count is a laboratory fact about a body, not a sighting at sea. Árnason worked at the Institute of Genetics in Lund. Kurihara's group is in Utsunomiya. Both papers describe a huge X chromosome loaded with C-heterochromatin. Kurihara calls it a huge subtelocentric X. The reading is a fusion away from the general cetacean 2n = 44 karyotype.
What it does not
Not every Mesoplodon species. Not the sperm whale or the pygmy sperm whale. Not Ziphius, and not the baleen whales, on this card. Not Adams. M. densirostris is a later count. These two papers do not report it.
ExactnessExact
Form42
Unitchromosomes
Strengthhard
When1978
Hung24 September 2026