Many planktonic organisms produce 'resting' stages when the environmental conditions deteriorate. Like seeds, resting stages can survive unfavourable conditions. The crustacean Daphnia normally reproduces by means of parthenogenetically produced normal, not resting, eggs-but occasionally switches to bisexual reproduction, which results in two resting eggs encased in a robust structure carried on the back of the female. This 'ephippium' is shed with the next moult, and can survive dormant for many years. The induction of resting-egg production requires multiple environmental stimuli, one of them being photoperiod. The switch from production of parthenogenetic eggs to resting eggs in Daphnia has recently been shown to be influenced by a maternal food effect. Here we present evidence that female Daphnia transmit information not only about food but also on photoperiod to their offspring, and influence the production of resting eggs in the next generation. The combined maternal effects can be relevant for the correct timing of resting-egg production-for example, in discriminating between spring and autumn conditions.

Vanfleteren J. R. (2006). A redescription of Eucyclops serrulatus (Fischer, 1851) (Crustacea: Copepoda: Cyclopoida) and some related taxa, with a phylogeny of the E. serrulatus -group. -Zoologica Scripta, 35, 123-147 . Eucyclops serrulatus (Fischer, 1851) , the type species of the genus Eucyclops , is redescribed from specimens found in the St. Petersburg area, Russia (type locality) and compared with specimens from Siberia, western Europe and North Africa. A neotype is selected. Cultures were set up, and interpopulation hybridization as well as hybridization with related species was attempted. The classical description of external body morphology was combined with pore signature mapping and with DNA nuclear small subunit (18S) ribosomal gene sequence analysis.Comparisons with E. dumonti Alekseev, 2000 , E. hadjebensis Kiefer , E. speratus Lilljeborg , E. turcomanus Lindberg, and E. pectinifer (Cragin, 1883) were carried out. A phylogenetic tree based on molecular information shows that E. serrulatus and E. speratus should be regarded as separate species. E. dumonti also deserves species status, but not E. hadjebensis . A cladistic tree based on the pore pattern of the cephalosome agrees well with a tree based on the sequence of the 18S rDNA gene. Cephalosome (and probably metasome) pore patterns seem useful to elucidate relationships within genera, while urosomal pore patterns better reflect the relationship between genera. E. serrulatus occurs in three morphological forms over most of its range; one of these (C) might be a rare ('recessive') morphotype, while forms A and B differ in microhabitat choice, but hybridize when living together. The same polymorphism also occurs in an American species ( E. prionophorus ), and therefore two hypotheses regarding its origin are advanced: either forms A and B evolved during the glacial episode (Pleistocene origin), separately on both sides of the Atlantic, or the polymorphism was already present in the ancestor of the serrulatus -group, and was later lost in some but not in all species (Pliocene origin.) Victor Alekseev,

Eurytemora carolleeae sp. nov. (Crustacea: Copepoda: Calaniformes) is described from the Chesapeake Bay, USA. The new species belongs to the Atlantic clade of the Eurytemora affinis complex outlined by previously published molecular work but poorly characterized morphologically. To discriminate E. carolleeae we compare specimens from the Atlantic USA clade with specimens from the type population of E. affinis (Poppe, 1880) from the Elbe River Estuary (Germany), as well as with eight other European coastal populations. Several important morphological characters clearly separate the North American E. cf. affinis from the European clade that include both sexes: a large outside orientated dent on the mandible, and clearly observable seta segmentation in the caudal rami and swimming legs. Unlike E. affinis, the newly described species possesses wing-like outgrowths on the genital double-somite and a very small spine near the distal seta insertion point in P5 in females. In males, the specific characters include naked dorsal and ventral sides of the caudal rami, and a cylindrical shape of exopod on the left P5, in contrast to a triangular shape of the segment in E. affinis. The new species was also found in Canada (St. Lawrence Estuary) and as an invasive species in the Baltic Sea. Eurytemora carolleeae is possibly widely distributed along the North American Atlantic coast, as well as in inland waters from Great Lakes to Mexico.

Interest in cryptic species has increased significantly with current progress in genetic methods. The large number of cryptic species suggests that the resolution of traditional morphological techniques may be insufficient for taxonomical research. However, some species now considered to be cryptic may, in fact, be designated pseudocryptic after close morphological examination. Thus the “cryptic or pseudocryptic” dilemma speaks to the resolution of morphological analysis and its utility for identifying species. We address this dilemma first by systematically reviewing data published from 1980 to 2013 on cryptic species of Copepoda and then by performing an in-depth morphological study of the former Eurytemora affinis complex of cryptic species. Analyzing the published data showed that, in 5 of 24 revisions eligible for systematic review, cryptic species assignment was based solely on the genetic variation of forms without detailed morphological analysis to confirm the assignment. Therefore, some newly described cryptic species might be designated pseudocryptic under more detailed morphological analysis as happened with Eurytemora affinis complex. Recent genetic analyses of the complex found high levels of heterogeneity without morphological differences; it is argued to be cryptic. However, next detailed morphological analyses allowed to describe a number of valid species. Our study, using deep statistical analyses usually not applied for new species describing, of this species complex confirmed considerable differences between former cryptic species. In particular, fluctuating asymmetry (FA), the random variation of left and right structures, was significantly different between forms and provided independent information about their status. Our work showed that multivariate statistical approaches, such as principal component analysis, can be powerful techniques for the morphological discrimination of cryptic taxons. Despite increasing cryptic species designations, morphological techniques have great potential in determining copepod taxonomy.