02374nas a2200277   4500008004100000245009400041210006900135260000900204300001400213490000700227520154400234653001801778653001201796653001401808653001401822653001201836653001701848653001701865653001401882653001001896653000901906653001901915100001501934700002101949856012601970       1993                        eng d00aSubstructure of the axoneme of pterygote insect spermatozoa - phylogenetic considerations0 aSubstructure of the axoneme of pterygote insect spermatozoa phyl  c1993  a449 - 4580 v223 aSpermatozoa from a great number of insect species were fixed in a tannic acid-containing fixative and the ultrastructure of the flagellar axoneme was examined in a search for apomorphies. Most of the examined species, representing a majority of insect orders, have accessory tubules outside the axoneme (hence a 9 + 9 + 2 pattern), and these consist of 16 protofilaments. Some important apomorphies concern the number of protofilaments in the accessory tubules: 13 (plus 7 inner elements) in Ephemeroptera, 13 in the (elliptic) tubules of Psocoptera + Anoplura + Mallophaga (thus a synapomorphy), 13 in Tipulidae + Brachycera, 15 in the dipteran families Dixidae + Chironomidae (with a 9 + 9 + 2 axoneme) and Culicidae + Bibionidae (with a 9 + 9 + ''1'' axoneme), 17 in Phasmatodea, and 17-20 in Trichoptera. Other apomorphies concern the appearance of the so-called intertubular material outside the microtubular doublets, the appearance of the interior of the various microtubules, and the loss, in some taxa, of outer or inner dynein arms of both dynein arms. In some cases, the flagellum is completely abnormal; the sperm tail of Thysanoptera, for example, consists of 27 elements of 3 different kinds. The different taxa within orders Diptera and Trichoptera have sperm tail axonemes of different appearances, where those from other orders have a rather uniform appearance. The conclusions that can be drawn from this spermatological study, generally agree with data from classical studies, except with some variations, in some cases.10acecidomyiidae10aDiptera10aDiversity10aflagellum10ainsects10amicrotubular10amicrotubules10aPhylogeny10asperm10atail10aUltrastructure1 aDallai, R.1 aAfzelius, B., A.  uhttps://phthiraptera.myspecies.info/content/substructure-axoneme-pterygote-insect-spermatozoa-phylogenetic-considerations