Helochares, MULSANT, 1844

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 HELOCHARES MULSANT, 1844

( FIG. 11D–L, N )

Material examined: Helochares lividus (Forster, 1771) : 2 spec. ( BMNH): United Kingdom, Somerset, Shapwick , R. Angus lgt .; 1 spec. ( BMNH): Spain, Provincia de Santander, Embalse de Ebro , R. Angus lgt .; 1 spec. ( BMNH): Italy, Sardinia, Nuoro Province , R. Angus lgt .

Helochares obscurus (Müller, 1776) : 1 spec. ( BMNH): Sweden, Öland , R. Angus lgt .

Helochares punctatus Sharp, 1869: 3 spec. (BMNH): United Kingdom, Surrey, Chobham , R. Angus lgt .; 2 spec. ( BMNH): United Kingdom, Hampshire, New Forest , R. Angus lgt .

Helochares sauteri dʼ Orchymont, 1943: 3 spec. (NMPC): Taiwan, 2.5 km E of Tonglin , 24.06288°N 120.76323°E, 3.x.2018, M. Fikáček, F.-S. Hu, W.-R. Liang & H.-C. Liu lgt.

Karyotype: 2 n = 16 + Xy p (♂). In Helochares lividus ( Fig. 11D–E ), pairs 1–6 are metacentric, whereas pairs 7, 8 and the X are submetacentric; there are small centromeric C-bands on all the chromosomes except the Y. In Helochares obscurus ( Fig. 11F ), pairs 1–7 are metacentric, pair 8 is subacrocentric and the X chromosome submetacentric. In Helochares punctatus ( Fig. 11G–H ), the autosomes are all metacentric, the X chromosome is submetacentric and all chromosomes possess large centromeric C-bands. Some H. punctatus appear to have up to three dotlike Y chromosomes; however, the additional two dots are probably B-chromosomes. Helochares sauteri from Taiwan ( Fig. 11L ) differs from the other species in its small acrocentric X chromosome, only half the length of the smallest autosome.

SUBFAMILY CYLOMINAE

Figures

Figure 11. Karyotypes of the Acidocerinae. A–C, Agraphydrus, mitotic metaphase, midgut: (A–B) Agraphydrus decipiens; (C) Agraphydrus variabilis. D–L, Helochares: (D–E) Helochares lividus, mitosis, midgut; (F) Helochares obscurus, mitosis, midgut; (G–H) Helochares punctatus, mitosis, midgut; (I) Helochares punctatus, karyotype of male embryo with multiple y-chromosomes; (J–K) meiotic metaphase I from testes (J, Helochares punctatus; K, Helochares lividus); (L) Helochares sauteri, mitosis, midgut.A, D, F, G, I–L, without treatment. B, C, E, H, C-banded. Habitus figures: (M) Agraphydrus decipiens, from Minoshima, Komarek, & Ȏhara 2015; (N) Helochares obscurus.