A. Guidi et L. Rebecchi, SPERMATOZOAN MORPHOLOGY AS A CHARACTER FOR TARDIGRADE SYSTEMATICS - COMPARISON WITH SCLERIFIED PARTS OF ANIMALS AND EGGS IN EUTARDIGRADES, Zoological journal of the Linnean Society, 116(1-2), 1996, pp. 101-113
The male gamete, a cell widely used for evaluating phylogeny in differ
ent animal groups, remains relatively unknown in tardigrades. In this
paper the spermatozoa of thirteen species of eutardigrades among four
genera and three families is evaluated in order to determine whether s
perm morphology can be used as a taxonomic character. Spermatozoa of A
mphibolus volubilis and A. weglarskae are very similar and this resemb
lance is congruent with the remarkable similarity of sclerified parts
of the species. In addition, the spermatozoa of eight species of the g
enus Macrobiotus were examined yielding two groups showing strong intr
agroup similarities. The first group includes M. pseudohufelandi, M. s
andrae, M. macrocalix, M. terminalis and M. joannae, and the second M.
richtersi, M. areolatus and M. harmsworthi. Again, these groupings we
re congruent with those determined by analysis of sclerified structure
s. In contrast, a marked similarity was found between the spermatozoa
of Diphascon (Adropion) scoticum and Platicrista angustata, whereas Di
phascon (Diphascon) humicus was appreciably different from both specie
s. Resemblances found in this study between spermatozoa and sclerified
body parts suggests that the spermatozoa are suitable characters for
use in systematic studies. (C) 1996 The Linnean Society of London