Larvae of two parasitic barnacles, Parasacculina pilosella (Van Kampen et Boschma, 1925) (Rhizocephala: Polyascidae) and Sacculina pugettiae Shiino, 1943 (Rhizocephala: Sacculinidae) studied by scanning electron microscopy.

The complete larval development of Parasacculina pilosella (Van Kampen et Boschma, 1925) and Sacculina pugettiae Shiino, 1943 including five naupliar stages and one cypris stage is described and illustrated using SEM. P. pilosella and S. pugettiae have a sacculinid type of development. Nauplii possess a naupliar eye, short frontolateral horns with terminal processes, and a ventral process between the furcal rami. Larvae lack a flotation collar, seta 6 on the antennule and a seta on the antennal basis. Cyprids have a nearly straight LO2. Breakage zone and a spinous process are present only in male larvae. Nauplii of the two species differ by the morphology of the furca: in P. pilosella, the furcal rami are longer and not drowned into cuticular sockets. Naupliar antenna of S. pugettiae has a lateral seta on the endopod which is lacking in P. pilosella. Dorsal head shield setae 1 and 2a are present in S. pugettiae nauplii and not found in P. pilosella larvae. In P. pilosella, all dorsal setae have subterminal pores, whereas in S. pugettiae, pores of the setae 2 are shifted proximally. It is possible that the presence/absence of setae 1 and 2a is the distinctive feature of nauplii of the families Sacculinidae and Polyascidae.

A new species of Cypris (Crustacea: Ostracoda) from the Iberian Peninsula and the Balearic Islands, with comments on the first ostracod named using the Linnean system.

The genus Cypris, considered the oldest ostracod generic name erected using the Linnean system, comprises a reduced number of large-bodied species, mostly found in Africa and Asia. Only six of them are known to occur in Europe. Here we describe a new species, Cypris pretusi sp. nov., collected in small temporary streams and ponds along the Eastern Iberian Peninsula and Minorca (Balearic Islands). The new species is very close to the type species of the genus, Cypris pubera O.F. Müller, 1776, but differs from it in having a set of smaller subequal spines on the posterior edge of the valves, by the absence of conspicuous spines along the front edge, and by the beak-like frontal shape of its carapace in dorsal view, similar to Cypris decaryi Gauthier, 1933. Soft parts are very similar to the type species, but it differs in having shorter swimming setae on the second antennae. Molecular analyses of the COX1 region support its status as a species distinct from C. pubera and closer to Cypris bispinosa Lucas, 1849, also providing evidence for a separation of C. pubera s.l. in two clades, one of which is here considered to correspond to Cypris triaculeata Daday, 1892. We discuss the relationships of C. pretusi sp. nov. to other members of the genus and its possible origin from nearby biogeographic regions (probably Africa or Asia) and provide a key to species of Cypris found in Europe. We also discuss the relationship between Monoculus concha pedata (= M. conchaceus), the first ostracod named by Linnæus, and Cypris pubera, the type species of the genus, described by Müller in 1776 and considered by him the same species as the one first named by Linnæus.

A new internal structure of nauplius larvae: A "ghostly" support sling for cypris y left within the exuviae of nauplius y after metamorphosis (Crustacea: Thecostraca: Facetotecta).

Facetotecta, or crustacean "y-larvae," occur in all the world's oceans although the adult forms remain completely unknown. At the metamorphic molt from the last naupliar instar to the terminal cypris larval stage a free carapace, six pairs of natatory thoracopods, and a segmented thorax and abdomen all develop anew. Unlike in earlier molts, the cephalic shield and the so-called "faciotruncal integument" usually remain together at this last naupliar molt, and the posterior "trunk" portion of the exuviae, while hollow, is not empty. In mounted preparations examined by phase contrast or differential interference contrast (DIC) microscopy, a ghost-like image of part of the cypris thorax, particularly the thoracopods and even their setae, is commonly visible inside the naupliar exuviae, and may be universally present in the Facetotecta. To investigate this "ghost," we used DIC and digital photographic stacking, and also scanning electron microscopy, on slide or stub-mounted final naupliar exuviae of an assortment of undescribed species of Facetotecta that had been reared from planktonic lecithotropic nauplii to the cypris stage at Sesoko Island, Okinawa, Japan, and at Keelung and Green Island, Taiwan. These techniques showed that the "ghost" is a delicate, three-dimensional, fibrous structure, essentially a sling-like mold or matrix with struts attached to the outer cuticle and pairs of deep pockets that previously held the thoracopods of the developing cypris y. Whether it is endoskeletal in nature, the (partial) exuvia of an additional instar, remnants of apoptosis, or something else is currently unknown. Nothing similar has been reported in other thecostracans, or in other crustaceans that undergo a similarly abrupt metamorphosis at the last naupliar molt.

Chlorine dioxide as an alternative antifouling biocide for cooling water systems: Toxicity to larval barnacle Amphibalanus reticulatus (Utinomi).

Chlorine dioxide (ClO2) is seen as an effective alternative to chlorine, which is widely used as an antifouling biocide. However, data on its efficacy against marine macrofoulants is scanty. In this study, acute toxicity of ClO2 to larval forms of the fouling barnacle Amphibalanus reticulatus was investigated. ClO2 treatment at 0.1mg/L for 20min elicited 45-63% reduction in naupliar metamorphosis, 70% inhibition of cyprid settlement and 80% inhibition of metamorphosis to juveniles. Increase in concentration to 0.2mg/L did not result in any significant difference in the settlement inhibition or metamorphosis. Treatment with 0.2mg/L of ClO2 elicited substantial reduction in the settlement of barnacle larvae compared to control. The study indicates the possibility of using ClO2 as an alternative antifouling biocide in power plant cooling water systems. However, more work needs to be done on the environmental effects of such switchover, which we are currently undertaking.

Ptychoptera deleta Novák, 1877 from the Early Miocene of the Czech Republic: redescription of the first fossil attributed to Ptychopteridae (Diptera).

The first fossil that was described in Ptychopteridae, Ptychoptera deletaNovák, 1877 from the classical Early Miocene locality Mokrina (Krottensee) in western Bohemia is re-examined. The re-description of the holotype including a new line drawing and remarks summarizing the scarce fossil record of this group is provided.