Chromosomes of four species of dobsonflies, in the genus Protohermes (Megaloptera, Corydalidae, Corydalinae) from East Asia

By

Yoshinori, Takeuchi
Koji, Iizuka
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

75--82

Subjects

Chromosomes , dobsonflies , Protohermes , sex chromosomes , XX/Xyp

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.19.146501

 

Abstract

We analyzed chromosomes of four species of East Asian dobsonflies (Megaloptera: Corydalidae): Protohermes grandis (Thunberg, 1781), P. immaculatus Kuwayama, 1964, P. disjunctus Liu, Hayashi et Yang, 2007 and P. costalis (Walker, 1853). The chromosome number in all species was 2n = 24, consisting of 11 pairs of autosomes plus the XX chromosomes in females and the Xyp in males. The karyotype of P. immaculatus which occurs in near the central part of the Ryukyu Islands, and is a vicarious species of P. grandis, was similar to the karyotype of P. grandis. On the other hand, the karyotype of P. disjunctus, which is from the Sakishima Islands, and is a vicarious species of P. costalis, resembled that of P. costalis.<br> The X chromosomes are submetacentric, while the Y is the smallest, dot-like chromosome of the set. The sex chromosomes of the first meiotic metaphase (MI) spermatocytes in all species invariably appear as a bivalent-like structure known as parachut bivalents Xyp, suggesting that the species in this genus share a common sex-bivalent mechanism.