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This paper presents a fully automated procedure for the detection of trees affected by Xylella Fastidiosa using UAVs and convolutional neural networks. Drones are able to collect an adequate number of olive leaf images to detect the presence of disease symptoms. Several neural networks are trained to compare results and determine the best solution.

Data on the external morphology are reviewed and new information is provided about the structure of the first naupliar instar of Parthenopea subterranea Kossmann, a rare and poorly known species of rhizocephalan barnacles. The taxonomic position of P. subterranea, which has so far been uncertain, is discussed. A new family, Parthenopeidae fam. nov., is erected to include a single genus, Parthenopea, with a single species, P. subterranea. The distinctive characters of the new family are described.

Within parasitic barnacles of the family Sacculinidae, the genus Heterosaccus is the third largest, with 12 species infesting various brachyuran hosts throughout the world. As part of an effort to reconstruct rhizocephalan phylogeny we performed an analysis of four species of Heterosaccus and of selected sacculinid and non-sacculinid rhizocephalans. We used both molecular sequence data (16s rDNA and 18s rDNA) and morphological characters from an SEM analysis of the cypris larvae. Using Bayesian methods we obtained a highly supported tree in which the four species of Heterosaccus form a monophylum, whereas both the genus Sacculina and the family Sacculinidae are polyphyletic. The sistergroup to Heterosaccus is a clade consisting of the sacculinids Loxothylacus panopaei and the "classical" rhizocephalan Sacculina carcini. The molecular results found support in cypris morphology, where we identified two distinct synapomorphies for Heterosaccus, both present in male cyprids only: A large flap extending posteriorly from the third antennular segment, and the male-specific aesthetasc on the third segment being reduced to a rudiment or lacking completely. Female cyprids didn't show generic level apomorphies but resembled those of other sacculinid species. No morphological synapomorphies were identified between Heterosaccus, L. panopaei and S. carcini. While larval characters proved to be informative, we conclude that future studies on rhizocephalan taxonomy must rely primarily on molecular data, both to provide an overall phylogenetic framework and to assure an accurate identification of species for biogeographical and other biological purposes.

Larval development of the parasitic barnacle Heterosaccus papillosus (Cirripedia: Rhizocephala: Sacculinidae) is described from larvae reared in the laboratory. Lecithotrophic nauplii of H. papillosus reached the cypris stage in 3·5 days, at 22–23°C. The development included five naupliar and the single cypris stage, thus following the typical pattern in the Rhizocephala Kentrogonida. Like the nauplii of all sacculinids, those of H. papillosus had a single pigmented nauplius eye, unsegmented frontolateral horns each with two long spines and a tubercle between the furcal rami, but they lack a flotation collar and have no seta on the antennal basipod. The male larvae are larger than female ones, the mean lengths in the two sexes never overlap. The most interesting feature of this species are the morphological differences between the male and female larvae. In the male nauplii III to V the anterior body margin is noticeably convex, that is not characteristic for female larvae. The male cyprid also has a more acuited anterior region, whereas that of the female is rounded.

We studied the infestation level of the coastal crab Hemigrapsus sanguineus by a cirripede barnacle Polyascus polygenea in Peter the Great Bay (Vostok Bay, Sea of Japan) in 1998–1999. It is shown that the externae of the parasite usually appear on the surface of the host’s body at the time when the crab attains sexual maturity (at a carapace width of 14–15 mm). More often we encountered infested crabs of a medium size, with a carapace width of 25–29 mm. The level of crab invasion did not depend on the sex of the host. In the summer period the proportion of infested crabs in different habitats ranged from 7 to 84%. The greatest number of crabs bearing the externae of the parasite was registered in an area with a boulder-pebble surface and small surf waves.

Thylacoplethus isaevae, a new species of colonial rhizocephalans, is described from the hermit crab Pagurus trigonocheirus collected in the Sea of Okhotsk, along the coast of Sakhalin Island. The new species differs from other known species of Thylacoplethus by the presence of complex spermatogenic bodies located within the mantle and the significantly larger size of its externae.

Nauplii of the rhizocephalan families Peltogastridae and Lernaeodiscidae carry a torus-shaped collar around the body. It consists of an exceedingly thin cuticle connected to the general body cuticle along a continuous narrow ridge. In nauplii of some species, the collar is very large and its surface ornamented by a very conspicuous reticulated pattern of ridges. In other species the collar is smaller and with a smooth surface that impedes its detection when using a light microscope. The collar is absent from nauplii of all investigated species of the Sacculinidae. Transmission electron microscopy shows that the collar of the succeeding nauplius instar is formed in an unexpanded state beneath the old cuticle and it must therefore be inflated at or immediately after ecdysis. At ecdysis the collar of the old instar breaks along the attachment ridge, leaving the empty collar and the exuvium of the general body as separate objects. The collar must have a profound influence on the hydrodynamic properties of the nauplius, both when swimming and passively sinking. We therefore consider it as a “floatation device”, a view supported by the absence of the collar in the rapidly swimming cypris larvae. There is no obvious homology to the collar outside the Rhizocephala, and it therefore appears to have evolved only once.

Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca but their evolutionary origin and possible homologues in other Crustacea remain obscure. We have used scanning electron microscopy to describe the setation pattern of the head shield in late nauplii of one species of Ascothoracida, one species of Facetotecta and several species of the Cirripedia Thoracica, Acrothoracica, and Rhizocephala. The naupliar head shield always carries two pairs setae situated anteriorly near the midline. Each of these setae carry a single pore, and positional, structural and ontogenetic evidence show that these setae are homologous in all the examined species and that they represent precursors of the two anterior pairs of lattice organs of the succeeding larval stage, viz., the ascothoracid larva (Ascothoracida), y-cyprid (Facetotecta), and cyprid (Cirripedia). This leads us to infer that lattice organs are among the most highly modified sensilla in all Crustacea and they have in most cases lost all external resemblance to a seta. The nauplii of the Rhizocephala carry an additional three pairs of setae situated more posteriorly on the head shield and they could be precursors of the three posterior pairs of lattice organs. All other species examined lack these posterior setae, except the Facetotecta which have one posteriorly situated pair.

SEM and light microscopic studies on the larvae of the rhizocephalan barnacles Peltogasterella gracilis and P. sulcata reared in the laboratory revealed the presence of 5 naupliar instars, the newly found stage being instar 3. It resembles instar 2 but is larger and has a body slightly tapering towards the posterior end, a reduced subapical (preaxial) seta on the antennule, and both transverse grooves and a specific denticle ornamentation on the hind body of female larvae. In cultures, the larvae of both species develop into cyprids within 4-5 days after release. Peltogasterella nauplii have a size comparable to that seen in Sacculina and Peltogaster, but they are much smaller than the larvae of the cold-water Briarosaccus. The nauplii of Peltogasterella are lecitotrophic and have limb setation and other feeding structures highly reduced. Peltogasterella nauplii have a cuticular flotation collar encircling the body, but it is very small, delicate, and almost smooth. It therefore differs from the homolo- gous, but much larger, and heavily ornamented flotation collars seen in nauplii of Peltogaster and Briarosaccus. A characteristic feature in Peltogasterella nauplii is the single subterminal seta at the distal end of each frontolateral horn, whereas nauplii of Briarosaccus and Peltogaster have two such setae. The antennulary basipod carries a short additional seta, which represents the only remaining rudiment of gnathobases. Nauplii of Briarosaccus and Peltogaster have a homologous, but significantly longer seta, whereas Sacculina nauplii lack this seta altogether. The nauplii of P. gracilis and P. sulcata are very similar in size and morphology, but those of P. sulcata differ by somewhat longer frontolateral horns and furcal spines. Another distinctive feature of P. gracilis nauplii is the ven- tral ornamentation of the hind body that shows different pattern at different stages of development and reflects an internal development of segments. This ornamentation is only weakly pronounced in P. sulcata nauplii. Compari- son with larval development in Briarosaccus tenellusleads to the conclusion that the rhizocephalan ground pattern comprises six naupliar stages just as in other cirripedes (e.g., Thoracica). Comparison of lattice organ morphology indicates a sister group relationship between the families Peltogastridae and Lernaeodiscidae. Our study highlights the value of SEM revealed larval characters and of characters other than appendage setation as being important in rhizocephalan phylogeny.

Scanning electron microscopy is used to examine the mantle surfaces of the reproductive body (externa) in a range of rhizocephalan barnacles. The cuticular structures called retinacula are described in detail and classified into various morphological types. The retinacula can be single or grouped in repeated patterns, or even united by a common base into a variety of complex structures. The surface of the individual retinaculum can be smooth or ornamented in various ways. The different types of retinacula intergrade to some extent and may all be derived from a single type, but they exhibit taxonomically informative differences. They are comparatively easy to study on traditional alcohol specimens and seem to offer the potential of an important suite of taxonomic characters which can be used also by non-specialists. It is recommended that all future species descriptions in the Rhizocephala use SEM to illustrate retinaculum morphology.

Larval development of the rhizocephalanSacculina polygenea (Crustacea: Cirripedia: Rhizocephala) parasitizing the coastal crabHemigrapsus sanguineus was studied in Vostok Bay, the Sea of Japan. At 22–23°C, the entire cycle of larval development takes 2.5 days and includes five naupliar stages and one cypris stage. Like other rhizocephalans, the larvae ofS. polygenea are lecithotrophic and only grow slightly in size in the course of development, and like all sacculinids, they have no flotation collar. The naupliar stages IV and V have a tubercle between the furcal rami; this tubercle is absent in the larvae of the genusPeltogasterella, but it has been described inS. carcini. The first seta of the antennule only disappears completely at the fourth stage, although it is markedly reduced at the third stage. No morphological differences, except differences in size, are found between male and female nauplii.

The morphology and disposition of lattice organs, putative sensory structures in the carapace of cyprids, are described with scanning electron microscopy from six rhizocephalan species representing four of the five families in the suborder Akentrogonida: Clistosaccus paguri and Sylon hippolytes (Clistosaccidae), Arcturosaccus kussakini (Duplorbidae), Mycetomorpha vancouverensis (Mycetomorphidae), and Diplothylacus sinensis and Thylacoplethus reinhardi (Thompsoniidae). The disposition of pores and setae on the cyprid carapace is also surveyed. In T. reinhardi, poor quality of the specimens allowed only confirmation that lattice organs are present. Cyprids of all other species except M. vancouverensis have two anterior and three posterior pairs of lattice organs on the carapace, just as in almost all other Cirripedia. Cyprids of C. paguri and S. hippolytes are nearly identical in both general shape, carapace setation, and morphology of the lattice organs. In both species the lattice organs are oval–circular pore fields, except the second pair which is very elongate and match-shaped, a morphology unique to the Clistosaccidae. The similarities in cyprid morphology are interpreted as apomorphies supporting the monophyly of the recently rediagnosed Clistosaccidae. Both thompsoniid species have oval–circular lattice organs, indicating a possible sister-group relationship between the Clistosaccidae and the Thompsoniidae. None of the lattice organs of A. kussakini are oval or match-shaped. In M. vancouverensis there is only a single anterior pair of lattice organs, a probable autapomorphy. But the morphology of the M. vancouverensis cyprid is otherwise very reminiscent of those in the Rhizocephala suborder Kentrogonida, such as in being ornamented with numerous (> 100) carapace setae in no fixed pattern compared with the few (

We studied, under laboratory conditions, the larval development of a rhizocephalan barnacle Sacculina pilosellaVan Kampen et Boschma, 1925, which parasitizes the kelp crab Pugettia quadridens(de Haan) in Vostok Bay, Sea of Japan. It is shown that at 22–23°C, the whole cycle of larval development takes about 3 days. The larvae of S. pilosellaare lecithotrophic; their development, like in other rhizocephalans, comprises five naupliar instars. Like the larvae of all sacculinids, the nauplii of S. pilosellahave no flotation collar. In their structure, the larvae of S. pilosellaare similar to the nauplii of the “typical” sacculina, S. carcini(elongated body outline, long furcal branches, and weakly pronounced segmentation of the abdomen). On the other hand, the characteristic outgrowth inbetween the furcal branches that is characteristic of stages IV and V in S. carciniand S. polygeneais absent in the larvae of S. pilosella.The first seta on the antennula of S. pilosellacompletely disappears only at stage IV; however, at stage III, it is already significantly reduced. No morphological differences have been revealed between male and female larvae of S. pilosellaexcept certain size differences.

A revision of the suborder Akentrogonida Hafele (Cirripedia: Rhizocephala) is proposed, based upon characters concerning ontogeny, larval morphology, and metamorphosis. The original diagnosis of the suborder is amended to include several genera, previously considered to be incertae sedis. The family Sylonidae Boschma is reduced to a synonym of Clistosaccidae Boschma. The diagnosis of the family Chthamalophilidae Bocquet-Vedrine is amended to include the genera Boschmaella Bocquet-Vedrine and Bocquetia Pawlik. The new families erected are: Duplorbidae, new family, for the genera Duplorbis Smith, Cryptogaster Bocquet-Vedrine and Bourdon, and Arcturosaccus Rybakov and Hoeg; Mycetomorphidae, new family, for the genus Mycetomorpha Potts, and Thompsoniidae, new family, for the genus Thompsonia Hafele. The genus Pirusaccus Lutzen is still considered as incertae sedis, though its possible affinity to Thompsoniidae is emphasized. A list of all species of the Rhizocephala Akentrogonida is given with notes on hosts and geographical distribution. A key allows identification of all the families of the Rhizocephala.

We use sequences from the nuclear ribosomal genes, 18S and 28S to analyze the phylogeny of the Rhizocephala Akentrogonida including two species, Clistosaccus paguri and Chthamalophilus delagei , that are critical for understanding rhizocephalan evolution but have not previously been part of a molecularly based study. In addition we use light and scanning electron microscopy to compare the cypris larvae of C. paguri , Sylon hippolytes and two species of the family Thompsoniidae, since this larval stage offers a suite of characters for analyzing the evolution of these otherwise highly reduced parasites. The Rhizocephala Akentrogonida form a monophyletic group nested within a paraphyletic “Kentrogonida”. C. paguri and S. hippolytes are sistergroups confirming the monophyly of the Clistosaccidae that was originally based on similarities in the cypris larvae. We find numerous LM and SEM level similarities between the two species, many of which appear to be correlated with their specialized sexual system, where male cyprids use an antennule to implant cells into the virgin female parasite. Some of these traits are also found in cyprids of the thompsoniid species. We conclude that the special cypris morphology and the implantation of males by antennular penetration was present in the stem species to the Thompsoniidae and the Clistosaccidae and emphasize the power of larval characters in rhizocephalan systematics. C. delagei is a sister group to Boschmaella balani and the two are nested deep within the Akentrogonida. This confirms the monophyly of the Chthamalophilidae and falsifies the theory that C. delagei should represent the most primitive extant rhizocephalan. Instead, chthamalophilid rhizocephalans represent some of the most highly advanced members of the parasitic barnacles.

The parasitic barnacles, Rhizocephala, are a little known group within Australia with only seven described species from a coastline stretching approximately 59763 km. This study describes a new species of Rhizocephala, Sacculina nectocarcini. The description is based on a unique combination of features pertaining to the structure of the mantle papillae, the retinaculae and the male receptacles. Biological notes, prevalence and intensity of infection are reported for this rhizocephalan, infesting the red rock crab, Nectocarcinus integrifrons, collected from Western Port, Victoria, Australia.

Arcturosaccuskussakini, new genus, new species, is a rhizocephalan parasite of the ultraabyssal isopod crustacean Antarcturus zenkewitchi Kussakin, collected off the east coast of Iturup Island, Kuril Islands, Russia. The morphology of the Rhizocephala Akentrogonida is reviewed and compared to this new species. Arcturosaccus has multiple layers of cuticle in the mesenteric canal, and a few spermatogenic islets floating free in the mantle cavity. By these characters, the new species seems most closely related to the genera Duplorbis and Cryptogaster, but differs from them by (1) the presence of the paired ovary, (2) the position of the mesentery, and (3) the mantle aperture, and by the shape of the externa. Naupliar instars are absent in the life cycle of Arcturosaccus kussakini and the larvae hatch as cyprids.