Coelostoma, BRULLE, 1835

Angus, Robert B, Sadílek, David, Shaarawi, Fatma, Dollimore, Hayley, Liu, Hsing-Che, Seidel, Matthias, Sýkora, Vít & Fikáček, Martin, 2021, Karyotypes of water scavenger beetles (Coleoptera: Hydrophilidae): new data and review of published records, Zoological Journal of the Linnean Society 192 (3), pp. 958-958 : 958-

GENUS COELOSTOMA BRULLÉ, 1835

( FIG. 15A–C, H )

Material examined: Coelostoma orbiculare (Fabricius, 1775) : 1 male, 2 females ( BMNH): United Kingdom, Norfolk, East Walton , R. Angus & F. Shaarawi lgt .

Karyotype: 2 n = 26 + Xy (♂). The autosomes and the X chromosome are metacentric to submetacentric with strong centromeric C-bands. Autosome pair 6 has a distinct subterminal secondary constriction on its long arm. The Y chromosome is dot like, and there may be two small B-chromosomes in the examined specimens. All the nuclei are from eggs taken from a cocoon spun by one of the females. In total, 16 male and 6 female nuclei were photographed. The two small B-chromosomes were present in only one male nucleus.

Figures

Figure15. KaryotypesoftheCoelostomatiniand Protosternini.A–C,Coelostomaorbiculare,embryo(A,with B-chromosomes; B–C, without B-chromosomes). D–F, Dactylosternum flavicorne, embryo. G, Dactylosternum corbetti, mitosis, midgut. J–K, Protosternum abnormale, meiotic nuclei from testes. A–F, J, K, without treatment. G, C-banded. Habitus figures: (H) Coelostoma orbiculare; (I) Dactylosternum corbetti; (L) Protosternum abnormale, from Fikáček et al. (2018).