Tormissus, BROUN, 1893

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 TORMISSUS BROUN, 1893

( FIG. 13B–C, E )

Material examined: Tormissus magnulus Broun, 1893: 1 male (NMPC): New Zealand, Wellington (WL), Tararua Range, 1 km W of Titurea Dam, start of Greens Rd. , fragment of broadleaf forest with sparse understory with ferns and Pandanus : pitfall trap, 40.4295°S 175.66064°E, 145 m, 28.xi.2016, M. Fikáček & M. Seidel lgt. ( MM31 ). 1 male ( NMPC): New Zealand: Wellington , Wright Hill Reserve , along unnamed stream along Deliverance Tk., 41.29683°S 174.73285°E, 190 m, 18.xi.2017, D. Sadílek lgt. (2017- NZ 07; DNA extraction NZ 718) .

Karyotype: 2 n = 26 + Xy p (♂). Based on the specimen from Titurea Dam ( Fig. 13B, C, E ), the karyotype comprises 13 pairs of autosomes plus Xy sex chromosomes. The specimen from Wellington provided two suitable mitotic nuclei and one meiotic nucleus, all showing one chromosome pair less (not illustrated here), despite the Titurea and Wellington specimens being conspecific as confirmed by their DNA barcodes. The Wellington specimen clearly shows the Xy

p

configuration of sex chromosomes. We suppose that the lower number of chromosomes in the Wellington specimen is caused by a loss of a chromosome pair during preparation.

SUBFAMILY SPHAERIDIINAE

TRIBE OMICRINI

Figures

Figure 13. Karyotypes of the Cylominae, without treatment. A, D, Exydrus gibbosus, mitosis, midgut. B–C, E, Tormissus magnulus, mitosis, midgut. F–H, Rygmodus modestus (F–G, meiotic metaphase I, testes; H, mitotic karyotype, midgut). Habitus figures: (I) Exydrus gibbosus; (J) Rygmodus modestus, from Minoshima et al. (2018).