Polarity in cuticular ridge development and insect attachment on leaf surfaces of Schismatoglottis calyptrata (Araceae)

The plant cuticle is a multifunctional barrier that separates the organs of the plant from the surrounding environment. Cuticular ridges are microscale wrinkle-like cuticular protrusions that occur on many flower and leaf surfaces. These microscopic ridges can help against pest insects by reducing the frictional forces experienced when they walk on the leaves and might also provide mechanical stability to the growing plant organs. Here, we have studied the development of cuticular ridges on adaxial leaf surfaces of the tropical Araceae Schismatoglottis calyptrata. We used polymer replicas of adaxial leaf surfaces at various ontogenetic stages to study the morphological changes occurring on the leaf surfaces. We characterized the replica surfaces by using confocal laser scanning microscopy and commercial surface analysis software. The development of cuticular ridges is polar and the ridge progression occurs basipetally with a specific inclination to the midrib on Schismatoglottis calyptrata leaves. Using Colorado potato beetles as model species, we performed traction experiments on freshly unrolled and adult leaves and found low walking frictional forces of insects on both of these surfaces. The changes in the micro- and macroscale morphology of the leaves should improve our understanding of the way that plants defend themselves against insect herbivores.

Russeting in Apple Is Initiated After Exposure to Moisture Ends—I. Histological Evidence

Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. We recorded the effects of duration of exposure to water and the stage of fruit development at exposure on microcracking, periderm formation and cuticle deposition. Early on (21 or 31 days after full bloom; DAFB) short periods (2 to 12 d) of moisture exposure induced cuticular microcracking—but not later on (66 or 93 DAFB). A periderm was not formed during moisture exposure but 4 d after exposure ended. A periderm was formed in the hypodermis beneath a microcrack. Russeting frequency and severity were low for up to 4 d of moisture exposure but increased after 6 d. Cuticle thickness was not affected by moisture for up to 8 d but decreased for longer exposures. Cuticular ridge thickness decreased around a microcrack. In general, moisture did not affect cuticular strain release. We conclude that a hypodermal periderm forms after termination of moisture exposure and after microcrack formation. Reduced cuticle deposition may cause moisture-induced microcracking and, thus, russeting.

Three new and five known species of Diplopeltoides Gerlach, 1962 (Nematoda, Diplopeltoididae) from Sweden, and a revision of the genus

Eight species of Diplopeltoides are described from the Swedish west coast. Diplopeltoides suecicus sp. nov. has the cuticle with longitudinal striation visible only under SEM; cuticular plate underlying the cephalic cuticle around the amphid present; cephalic sensilla 4–6 µm long; amphid an inverted U-shape; wide space between amphidial branches areolated; spicules 27–31 µm long; gubernaculum with caudal apophysis. Diplopeltoides longicaudatus sp. nov. is characterized by a cuticle without longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 13 µm long; amphid an inverted U-shape; narrow space between amphidial branches not ornamented; spicules unequal in size, 27–31 µm long; gubernaculum absent; midventral precloacal cuticular ridge present. D. grandis sp. nov. is characterized by a cuticle with longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 18.5 µm long; amphid an inverted U-shape; wide space between amphidial branches punctate. The following taxonomic changes are proposed: Diplopeltoides asetosus (Juario, 1974) comb. nov., Diplopeltoides botulus (Wieser, 1959) comb. nov., Diplopeltoides bulbosus (Vitiello, 1972) comb. nov., Diplopeltoides lucanicus (Boucher & Helléouët, 1977) comb. nov., Diplopeltoides pumilus (Vincx & Gourbault, 1992) comb. nov. and Diplopeltoides striatus (Gerlach, 1956) comb. nov. Diplopeltoides holovachovi Fadeeva & Mordukhovich, 2013 is synonymised with Diplopeltoides pumilus comb. nov. An updated key to the species of Diplopeltoides is provided.

New littoral mite species (Acari, Oribatida, Fortuyniidae) from the Galápagos archipelago, with ecological and zoogeographical considerations

Two species of Fortuyniidae, found on the Galápagos Islands (Ecuador) are described and illustrated based on the adult and juvenile instars. Alismobates galapagoensis sp. nov. was found on six islands of the archipelago, in littoral and supralittoral habitats. It is morphologically similar to A. inexpectatus Pfingstl & Schuster, 2012 from Bermuda, but differs from that species and all other known congeners by a prominent cuticular ridge on epimeron III among other unique character combinations. Litoribates caelestis gen. and sp. nov. was found on the islands Santa Cruz and Bartolomé in the littoral zone under Maytenus and mangroves. Notes on distribution and ecological preferences of both species are included.

First description of a gastrotrich with four scale types, including feathered biancres, a novel find for Gastrotricha

A new species of Tetranchyroderma, T. garraffonii, is described from sublittoral sediments off the coast of Florida, USA. The new species possesses mixed scale types in the form of feathered biancres – a novel discovery for the genus – as well as feathered triancres and ordinary triancres. Biancres consist of a round scale base, a pair of ancre shafts that arise individually from a v-shaped cuticular ridge on the scale, and feathered ancres. Triancres are similar in appearance but have a different ridge pattern. Ordinary triancres occurred in two forms on the lateral sides of the body: a bowl-shaped ancre and a ‘pitchfork’ shaped ancre. Other distinguishing characteristics of the new species include the presence of cephalic tentacles, a papillated fringe to the oral hood, and a single pair of lateral and dorsolateral adhesive tubes at the posterior end. Confocal microscopy verified the presence of a muscular caudal organ and partly muscular vas deferens.

Prevalence and patterns of infection by the epicaridean parasite, Gyge ovalis and the emergence of intersex in the estuarine mud shrimp, Upogebia major

A population of the mud shrimp, Upogebia major, inhabiting Kasaoka Inlet had a higher frequency of intersex males compared to other populations in the Seto Inland Sea, Japan. This population also featured a high prevalence of the branchial epicaridean parasite, Gyge ovalis, and inhabited a tidal flat characterized by increasingly softer sediments going into the lower tidal areas. We examined the rates at which infection co-occurred with intersex features and checked whether infection patterns varied with intersex occurrence according to host size and tidal level position. Fewer specimens were both intersex and infected than those having only one of either condition; infection was not a significant predictor of intersex. However, infection in young hosts that recovered from the parasite could be associated with the intersex morphologies and account for the majority of cases that were intersex but parasite-free. Deletions of the cuticular ridge (CRD) between the first and second abdominal segment and tidal level position were correlated with intersex. Lower tidal zone mud shrimp were, respectively, three and four times more likely to be intersex and exhibit CRD than those in the upper tidal zone. Potentially inclusive factors that may influence these trends are higher rates of early infection and increased exposure to sediment-bound pollutants in mud shrimp inhabiting the lower tidal areas.

Morphological variation between isolates of the nematode Haemonchus contortus from sheep and goat populations in Malaysia and Yemen

Haemonchus contortus is a highly pathogenic nematode parasite of sheep and goats. This work was conducted to investigate the population and host variations of the parasitic nematode H. contortus of sheep and goats from Malaysia and Yemen. Eight morphological characters were investigated, namely the total body length, cervical papillae, right spicule, left spicule, right barb, left barb, gubernaculum and cuticular ridge (synlophe) pattern. Statistical analysis showed the presence of morphological variation between populations of H. contortus from Malaysia and Yemen, with minor variation in the synlophe pattern of these isolates. Isolates from each country were grouped together in the scatterplots with no host isolation. Body, cervical papillae and spicule lengths were the most important characters that distinguished between populations of the two countries. This variation between Malaysia and Yemen may be attributed to geographical isolation and the possible presence of a different isolate of this worm in each country.

Archeolourinia shermani, a new genus and species of Louriniidae (Copepoda: Harpacticoida) from a Caribbean mesophotic zone

Mesophotic coral ecosystems (MCEs) are found on the insular and continental slopes of Caribbean islands and comprise mainly scleractinian corals, sponges and macroalgae. These species provide habitat for a highly diverse and specialized crustacean fauna. A new genus and species of the family Louriniidae is described from samples taken from an MCE in south-west Puerto Rico. The new taxa can be diagnosed by: body elongate, almost cylindrical and with inconspicuous podoplean boundary between prosome and urosome; double genital somite with a discontinuous chitinized cuticular ridge; telson short with rectangular anal operculum; furca short; rostrum sinusoidal, well defined at the base; antennules 7-segmented with aesthetasc on the fourth segment; antenna with a brush-like basal seta and an abexopodal seta, exopod 1-segmented with 2 setae; endopod with 7 elements (1 geniculate seta and 1 modified inner spine); maxilliped well developed, prehensile, composed of syncoxa, basis, one segmented endopod and one claw-like apical seta; leg 1 endopod 3-segmented, first segment with a modified inner seta; legs 2, 3 and 4 with 2-segmented endopod with inner seta on the first segment; leg 5 basendopod fused, well developed with 4 setae, exopod well developed, with 5 setae; leg 6 represented by a single seta; and genital slits wide apart. The new genus and species can be confidently assigned to the family Louriniidae on the basis of the following synapomorphies: rostrum well-developed with rounded tip; antennule of female 7-segmented; mandible palp reduced; maxillule endopod and exopod absent; maxillae endopodite 2 represented by 3 setae; leg 5 basoendopod of female confluent, intercoxal sclerite absent, exopod 1-segmented; eggs retained in a single ventral egg sac; telson shorter than last urosomite; and furca short and with 6 setae.

Redescription of Desportesius brevicaudatus (Spirurida, Acuariidae) based on nematodes from Ixobrychus minutus (Aves, Ciconiiformes) from Bulgaria

Desportesius brevicaudatus (Dujardin, 1845) is redescribed on the basis of light-microscopy and SEM observations on specimens collected from the oesophagus and under the lining of the gizzard of Ixobrychus minutus (Ardeidae) from Bulgaria. New metrical data expand the known ranges of variation of the measurements of the body, tail, cordons, oesophagus and spicules. New information is provided on the variation of the shape of the deirids, the structure of the vagina, the complexity of the cordons, the pattern of the cuticular striation and the shape of the postdeirids. Cordons are described as consisting of a single row of serrate cuticular plates and a longitudinal cuticular ridge along the outer rims of the cuticular plates. The cuticular ridge is interpreted as homologous to the outer row of plates in the cordons of the genera Acuaria, Cheilospirura and Echinuria.