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Homology of the genital sclerites of M egaloptera ( I nsecta: N europterida) and their phylogenetic relevance
Author(s) -
LIU XINGYUE,
LÜ YANAN,
ASPÖCK HORST,
YANG DING,
ASPÖCK ULRIKE
Publication year - 2016
Publication title -
systematic entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 66
eISSN - 1365-3113
pISSN - 0307-6970
DOI - 10.1111/syen.12154
Subject(s) - biology , homology (biology) , phylogenetic tree , sex organ , zoology , confusion , anatomy , phylogenetics , evolutionary biology , genetics , gene , psychology , psychoanalysis
The genitalia of M egaloptera are crucial for taxonomic identification and represent a significant component of characters for phylogenetic interpretation of this order. However, several complex genital structures, especially those related to segments 9 and 11 in M egaloptera, have yet to be subjected to a comprehensive survey of homology. The terminology for genital sclerites has been variously and even incorrectly used by different authors, a fact which could lead to much confusion about character evolution. In this paper, we first present a comprehensive morphological comparison of the sclerites of male and female genital segments in 23 megalopteran genera representing all major lineages of C orydalinae, C hauliodinae and S ialidae. Accordingly, we then provide new interpretations on the homology of the genital sclerites which often appear to be considerably different among M egaloptera. Based on our new and revised homology assessments, we conclude that: (i) the small to medium‐sized sclerite beneath the ectoprocts in males of S ialidae represents the fused gonocoxites 11; (ii) the male gonocoxites 11 in C orydalidae are largely reduced and are sometimes retained as a small sclerite beneath the anus; (iii) the predominant sternite‐like sclerite of the female abdominal segment 8 represents the fused gonocoxites 8; and (iv) a pair of sclerites amalgamated with the lateral arms of male gonocoxites 10 in C hauliodinae is the gonocoxites 9. Furthermore, based on our genital homology assessments, we reconstruct an intergeneric phylogeny including all genera of M egaloptera using genital characters in a parsimonious analysis to test their phylogenetic relevance. The phylogeny herein recovered is largely congruent with the results from several previous studies, thus underlying the significant phylogenetic relevance of the megalopteran genital sclerites. The present work provides new insights into the evolution of insect genitalia.