In animals, cell polarity may initiate symmetry breaking very early in development, ultimately leading to whole-body asymmetry. Helical sperm cells, which occur in a variety of animal clades, are one class of cells that show clearly visible bilateral asymmetry. We used scanning-electron microscopy to study coiling direction in helical sperm cells in two groups of animals that have figured prominently in the sperm morphology literature, namely land snails, Stylommatophora (514 spermatozoa, from 27 individuals, belonging to 8 species and 4 families) and songbirds, Passeriformes (486 spermatozoa, from 26 individuals, belonging to 18 species and 8 families). We found that the snail sperm cells were consistently dextral (clockwise), whereas the bird sperm cells were consistently sinistral (counterclockwise). We discuss reasons why this apparent evolutionary conservatism of sperm cell chirality may or may not be related to whole-body asymmetry.

Anthropogenic environmental change is leading to changes in distribution for many organisms. While this is frequently discussed for prominent organisms of high conservation value, the same is true for the many cryptic species that rarely figure in debates on the human impact. One such cryptic taxon is the European Ptomaphagus sericatus (Chaudoir, 1845) and related forms. During a citizen science expedition in the Vondelpark, Amsterdam, the Netherlands, we obtained two forms of this species complex. We placed the examination of these specimens in the context of a re-analysis of the species group, and, using DNA barcoding and genital study on material collected thoughout Europe, found that the P. sericatus species complex consists of three distinct, partly sympatric species, one of which was previously undescribed. On the basis of collection data, at least two species, P. medius and P. thebeatles sp. n., show signs of having recently undergone (possibly anthropogenic) range changes, with P. medius even reaching North America. We describe P. thebeatles sp. n.; we raise two subspecies, viz. P. sericatus sericatus (Chaudoir, 1854) and P. sericatus medius (Rey, 1889) to the level of species, and designate a neotype for the former; we identify P. dacicus Jeannel, 1934 and P. pyrenaeus Jeannel, 1934 as junior synonyms of P. sericatus, and P. compressitarsus (Rey, 1889) as a junior synonym of P. subvillosus Goeze, 1777; we identify P. septentrionalis Jeannel, 1934 and P. miser (Rey, 1889) as junior synonyms of P. medius; we designate lectotypes for P. medius and P. miser.