Staurozoan classification is highly subjective, based on phylogeny-free inferences, and suborders, families, and genera are commonly defined by homoplasies. Additionally, many characters used in the taxonomy of the group have ontogenetic and intraspecific variation, and demand new and consistent assessments to establish their correct homologies. Consequently, Staurozoa is in need of a thorough systematic revision. The aim of this study is to propose a comprehensive phylogenetic hypothesis for Staurozoa, providing the first phylogenetic classification for the group. According to our working hypothesis based on a combined set of molecular data (mitochondrial markers COI and 16S, and nuclear markers ITS, 18S, and 28S), the traditional suborders Cleistocarpida (animals with claustrum) and Eleutherocarpida (animals without claustrum) are not monophyletic. Instead, our results show that staurozoans are divided into two groups, herein named Amyostaurida and Myostaurida, which can be distinguished by the absence/presence of interradial longitudinal muscles in the peduncle, respectively. We propose a taxonomic revision at the family and genus levels that preserves the monophyly of taxa. We provide a key for staurozoan genera and discuss the evolution of the main characters used in staurozoan taxonomy.

A method of recovering cysts from soils of not more than 10% water content is described. The method is continuous and the yield from it is only slightly lower than that from the dry flotation of soil. The yield was found to contain a slightly lower percentage of full cysts than that obtained by dry flotation but this drop was not considered sufficiently great to justify the drying of soil in large quantities. Quantities of soil in the neighbourhood of 1 cwt. can be handled continuously in a matter of two hours.

The marine nemertean Cephalothrix simula originates from the Pacific Ocean but in recent years has been discovered in northern Europe. The species has been associated with high levels of the marine neurotoxin Tetrodotoxin, traditionally associated with Pufferfish Poisoning. This study reports the first discovery of two organisms of C. simula in the UK, showing the geographical extent of this species is wider than originally described. Species identification was initially conducted morphologically, with confirmation by Cox 1 DNA sequencing. 16S gene sequencing enabled the taxonomic assignment of the microbiome, showing the prevalence of a large number of bacterial genera previously associated with TTX production including Alteromonas, Vibrio and Pseudomonas. LC-MS/MS analysis of the nemertean tissue revealed the presence of multiple analogues of TTX, dominated by the parent TTX, with a total toxin concentration quantified at 54 µg TTX per g of tissue. Pseudomonas luteola isolated from C. simula, together with Vibrio alginolyticus from the native nemertean Tubulanus annulatus, were cultured at low temperature and both found to contain TTX. Overall, this paper confirms the high toxicity of a newly discovered invasive nemertean species with links to toxin-producing marine bacteria and the potential risk to human safety. Further work is required to assess the geographical extent and toxicity range of C. simula along the UK coast in order to properly gauge the potential impacts on the environment and human safety.

Fifteen lots of fifty individual cysts from three separate batches were exposed to the action of potato root diffusate, the hatching allowed to continue to completion and the total larvae liberated from each cyst were counted. The data obtained were analysed both as they stood and after three different transformations for variability, as well as for independence between mean and variance. Very high variability corresponding to a coefficient of variation of 1.00 was detected, and there was, moreover, a very significant correlation between mean and variance. The most suitable transformations appeared to be either logarithmic or angular—the latter being probably the more useful. The latter, moreover, tended to increase the sensitivity of analysis. The importance of residual counts when hatching is complete is emphasized even in the absence of an angular transformation of the data.

Experiments were conducted in which single cysts and batches of 100 cysts were exposed to the action of potato-root diffusate and the number of larvae liberated at the end of certain intervals of time recorded. Investigation showed that when the hatch at the end of each time interval was expressed as a probit of the total hatch, and plotted against the logarithm of that time, a close approximation to linearity resulted. Statistical analysis confirmed this agreement in the case of single cyst hatching, but disclosed a significant degree of asymmetry in the case of multiple hatching. It was decided that the degree of curvature resulting from this when plotted as a probit line was sufficiently small for it to be ignored.