Chromosomes of four fishfly species (Megaloptera, Corydalidae, Chauliodinae) from North America

By

Yoshinori, Takeuchi
Koji, Iizuka
Tadashi, Nakazato
Hiroyuki, Koishi
Hidehiro, Hoshiba

Type

Article

Date of Publication

2025

Original Publication

Comparative cytogenetics : international journal of plant & animal cytogenetics, karyosystematics and molecular systematics

Volume

19

Pages

83--90

Subjects

Chromosomes , Dysmicohermes , fishflies , Nigronia , Orohermes , sex chromosomes , Xyp/XX

Contributed by

Pensoft Publishers

Language

English

Published by

St. Petersburg, Russia [Published] with technical support of Zoological Institute RAS [2007]-

Identifiers

DOI: https://doi.org/10.3897/compcytogen.19.146136

 

Abstract

We analyzed chromosomes of four species of fishflies (Megaloptera: Chauliodinae). Three species were from western North America (Dysmicohermes disjunctus (Walker, 1866), Dysmicohermes ingens Chandler, 1954, and Orohermes crepusculus (Chandler, 1954)), and another one from eastern North America (Nigronia serricornis (Say, 1824)). The chromosome number of the three western species was 2n = 22, with the karyotype consisting of 10 pairs of autosomes plus XY in males. The X chromosomes of these three species are subtelocentric, while the Y chromosomes are small and dot-like. Of the ten pairs of autosomes, the last pair is substantially smaller than the others. The chromosome number in the first meiotic metaphase in spermatocytes of N. serricornis from Michigan was n = 10 (9 autosomal bivalents + Xyp in the male). The sex chromosomes of N. serricornis formed parachute-type bivalents synchronously with the autosomes. The parachute-type bivalent Xyp has also been found in four fishflies and four dobsonflies (Megaloptera: Corydalinae) from East Asia, as well as in a fishfly and a dobsonfly from North America. These data suggest that the two subfamilies of Corydalidae share a common sex-bivalent mechanism, along with many beetles (Coleoptera).