Small Sucker Research Articles

Isolation and Characterization of <i>Striga hermonthica</i> Seed-Bank Depleting Bacteria from <i>Striga</i> Infested Sorghum Growing Areas of Ethiopia

<i>Striga hermonthica</i> is a very serios parasitic weed of (<i>Sorghum bicolor </i>L. Moench). It attack host plants by living as hemi-parasite and attaching small sucker root system to host plant. A study was undertaken to evaluate the effect of bacterial isolate obtained from soil samples collected from <i>Striga </i>infested sorghum growing fields in Amhara, Tigray and Oromia Regions to inhibit (deplete) the <i>Striga </i>seed bank. Surface sterilized and conditioned <i>Striga </i>seeds were buried in the soil by using teabag to determine germinated, viable and decayed seeds at different times after burial. A total of 44 isolates were isolated from germinated and decayed striga seeds and tested for their effect on germination and seed decay of <i>Striga </i>seeds. Six isolates (GS29, GS32, GS34, GS39, GS42 and GS45) were stimulated 10.33, 9.0, 9.67, 8.33, 5.33 and 8.33 <i>Striga </i>seeds germination from the total of 35 seeds respectively in the absence of host plant synthetic stimulant. On the other hand four isolates (SD3, SD9, SD36 and SD46) significantly decayed <i>Striga </i>seeds at P<0.05 (21, 20, 21.33 and 21 seeds respectively) in order to reduce <i>Striga</i> attack. Selected isolates were characterized by using biochemical tests, and three isolates were classified under the genus <i>Pseudomonas</i> while the other three isolates were grouped under the genus <i>Klebsiella.</i> The four isolates that showed seed decay were classified under the genus <i>Bacillus</i> morphologically.

Retaining the largest aspen stems during motor-manual release allows to control aspen suckering in young mixedwood stands

Mixedwood stands containing aspens (Populus tremuloides or P. grandidentata) often convert to hardwood-dominated stands after harvesting due to the rapid regeneration of aspen from root suckers, even when sites are promptly replanted with conifer seedlings. Without the use of herbicides, this problem is usually dealt with several passes of motor-manual (“manual”) release of overtopped seedlings. The aim of this study was to test a variation of thinning from below treatment (thinning; only 20% of the largest aspens are retained), and to compare it against two traditional release treatments: broadcast brushing (brushing; 100% removal of aspen) or crop tree release (CTR; removal of competing vegetation 60 to 90 cm around planted spruce) and an un-treated control. The thinning treatment left the 20% larger aspen stems in place, in order that they continue exerting apical dominance on smaller suckers and limit re-suckering of the treated plots. Aspen suckering and growth of planted black spruce seedlings (Picea mariana (Mill.) B.S.P) were measured two- and four-growing seasons following treatments. Results four years after release application showed that the thinning and CTR treatments reduced aspen density by 61% compared to the brushing treatment. In addition, aspen individual stem volume in the thinning treatment was almost 10 times larger than the brushing and twice that of the CTR treatments. Spruce height and ground collar diameter (GCD; 5 cm aboveground line) were both measured, and while height increment was similar in all treatments, diameter increment was greater in the thinning treatment (+42%) compared to the control, brushing and CTR treatments (+17%). Thinning yielded better short-term results than the brushing release in terms of aspen re-suckering and aspen sawlog potential, highlighting the need for adapted silvicultural treatments based on the species’ ecology.

Morphological description and mitochondrial DNA-based phylogenetic placement of a new species of Callistoctopus Taki, 1964 (Cephalopoda, Octopodidae) from the southeast waters of China.

In this study, we described a new species of octopus and named it Callistoctopusxiaohongxu sp. nov. based on nine specimens captured in the waters of southeast China. Callistoctopusxiaohongxu sp. nov. is a small to moderate-sized octopus. The most characteristic and defining morphological features are the reddish-orange to reddish-brown skin, gills with 8 or 9 lamellae per demibranch, \∧/-shaped funnel organ, and small suckers. Fragments obtained from the mitochondrial cytochrome c oxidase subunit I (COI) gene of nine specimens were 593 bp in length, and the genetic distance among the specimens of C.xiaohongxu sp. nov. and the other 16 octopods ranged from 11.13 to 21.09%. Topologies resulting from ML and BI analyses of the COI gene showed a highly supported monophyletic clade (bootstrap value [BS] = 94%, posterior probability [PP] = 100%) containing all the specimens identified as C.xiaohongxu sp. nov.

Neonematobothrium annakohnae n. sp. (Digenea: Didymozoidae) parasitizing Euthynnus alletteratus (Perciformes: Scombridae) in the Southwest Atlantic Ocean.

Describe a new species of didymozoid digenean Neonematobothrium Yamaguti, 1965 from the operculum of the scombrid fish, Euthynnus alletteratus (Rafinesque, 1810), in the Southwest Atlantic Ocean off Brazil. Thirty-four specimens of E. alletteratus were collected in the coastal zone of the state of Rio de Janeiro and obtained from local fishermen between 2006 and 2018 in the municipal market of São Pedro in Niterói, Brazil. The parasites were fixed in AFA (93% ethanol 70%, 5% formaldehyde, 2% glacial acetic acid) without pressure, stained with Langeron alcoholic acid carmine, dehydrated in an alcohol series, cleared in beachwood creosote or clove oil and mounted in Canada balsam as permanent slides. Neonematobothrium annakohnae n. sp. is a member of the genus based on a combination of the following characteristics: body free, uncapsulated; body long and dorsoventrally flattened; esophagus surrounded by gland cells; ovary and vitellarium single, long, narrow and unbranched in the anterior and posterior halves of the body, respectively; uterus with three loops; and site of infection in subcutaneous tissue of scombrid fish. The new species differs from the two recognized species of the genus mainly by the size of the body, which is much larger, the shape of the genital pore, which is differentiated in a structure similar to a small sucker and by esophagus without diverticula. Neonematobothrium annakohnae n. sp. parasite of E. alletteratus from the Southwest Atlantic Ocean, described herein, represents the third species of Didymozoidae belonging to the genus Neonematobothrium. The two known species Neonematobothrium kawakawa Yamaguti, 1965 and Neonematobothrium dorsale Yamaguti, 1970 were described from fish belonging to the same genus of the host from Pacific Ocean. The diagnosis of the genus is enlarged to "esophagus with or without diverticula", to fill the characteristics presented by the new species. The description of N. annakohnae n. sp. demonstrates the need to expand the studies of these interesting and intriguing group of parasites, due to the fact that number of known didymozoids taxa in the Atlantic Ocean is far from representing the real situation.

Investigation of complete life cycle and species identification of a digenean gill parasite <i>Centrocestus</i> sp. infesting Koi carp (<i>Cyprinus carpio</i> Linnaeus, 1758) using morphology and morphometric characters

This study was done to describe the morphology and morphometric characters of the life cycle stages of the digenean gill parasite, Centrocestus sp. that infests Koi carp (Cyprinus carpio) at Rambadagalle and Ginigathhena ornamental fish breeding centres of Sri Lanka and to identify the species of the parasite. The snail, Melanoides tuberculata (Muller, 1774) that inhabited the earthen ponds with Koi carps were induced to shed cercariae and 45 days old Koi carps were experimentally infested by them. The infected fish with mature metacercariae were fed to chicks (Gallus gallus) and eggs of the parasite released with faeces and adult stages of the parasite developed in the intestine were recovered. After keeping the eggs in water for several days ciliated miracidia were observed by application of tactile pressure. Infested snails were dissected and the morphometric characters of sporocyst and redia stages were recorded. The eggs were operculated, oval shaped, yellowish brown in colour with lattice design on the shell surface. The ciliated miracidi, was the infective stage to snails. The sporocyst was sac like and the redia was tubular and curved. The cercaria had an oral and a ventral sucker, two eye spots and a tail. The encysted metacercaria was oval in shape with ‘X-shaped excretory bladder’. Excysted metacercaria was elongated and narrower at the anterior end being similar to adults. The adult worm was small and oral sucker was surrounded by 32 circumoral spines arranged in two alternated rows. Acetabulum located in the middle of the body. The excretory bladder opened to a terminal excretory pore. The morphology and morphometric characters of the life cycle stages of the Centrocestus sp. that infests Koi carp at Rambadagalle and Ginigathhena ornamental fish breeding centres were compared with published literature and the parasite was identified as Centrocestus formosanus (Nishigori, 1924), which has not been documented in Sri Lanka earlier.

Effect of timing of diseased plant cutting, altitude and banana cultivar on efficacy of singly removing Xanthomonas wilt infected banana plants

The single diseased stem removal (SDSR) technology (i.e. timely cutting of diseased banana plants) is an important Xanthomonas wilt (XW) control method being promoted in XW-endemic zones of east/central Africa. Proper SDSR application leads to quick field recovery. However, its efficacy on farms has been variable. For example, delayed cutting of diseased stems/plants is postulated to increase Xcm inoculum buildup and risk of infection in other physically attached shoots, while larger suckers were thought to be less reliant on the mother plants for nutrients and water thus being less susceptible than small suckers. Previous SDSR evaluations took place at mid-high altitudes dominated by east African highland bananas whereas low-lying altitudes especially dominated by ABB types exist, and this site and type is more prone to insect-mediated XW infections. This study hence determined effects of: i) timing of cutting symptomatic plants on recovery of mats, ii) size of attached suckers at infection on their susceptibility to infection, and iii) the efficacy of SDSR at an ABB banana dominated low altitude site. XW incidence in suckers increased with a delay in cutting of symptomatic mother plants, with lowest incidence (0.27%) observed when symptomatic plants were immediately cut upon symptom expression and highest (1.61%) when plants decayed in situ. The larger maiden (32.1% diseased shoots) and sword suckers (22.2%) were significantly more susceptible than the small peepers (7.4%). XW incubation period was shorter for the maiden suckers (4.5 to 6.2 months) compared to 8.9–11.3 months for sword suckers and 11.3 months for peepers. Immediate cutting of plants after first visible symptoms should be recommended to farmers, while additional studies to understand the low susceptibility of small peepers would be warranted. SDSR was observed to be as effective at the ABB banana dominated low altitude sites as previously reported for highland bananas and environments.

Tracing ancient evolutionary divergence in parasites.

For parasitic platyhelminths that generally lack a fossil record, there is little information on the pathways of morphological change during evolution. Polystomatid monogeneans are notable for their evolutionary diversification, having originated from ancestors on fish and radiated in parallel with tetrapod vertebrates over more than 425 million years (My). This study focuses on the genus Polystomoides that occurs almost worldwide on freshwater chelonian reptiles. Morphometric data show a major divergence in structural adaptations for attachment; this correlates with a dichotomy in micro-environmental conditions in habitats within the hosts. Species infecting the urinary tract have attachment organs with large hamuli and small suckers; species in the oro-nasal tract differ fundamentally, having small hamuli and large suckers. Zoogeographical and molecular evidence supports ancient separation of these site-specific clades: a new genus is proposed - Uropolystomoides - containing urinary tract species distinct from Polystomoides sensu stricto in oro-nasal sites. Aside from differences in attachment adaptations, body plans have probably changed little over perhaps 150 My. This case contrasts markedly with polystomatids in other vertebrate groups where major morphological changes have evolved over much shorter timescales; the chelonian parasites show highly stable morphology across their global distribution over a long period of evolution, exemplifying 'living fossils'.

Accacoelium contortum (Trematoda: Accacoeliidae) a trematode living as a monogenean: morphological and pathological implications

BackgroundAccacoelium contortum (Rudolphi, 1819) Monticelli, 1893 is a frequent but poorly known trematode found on gills, pharynx and digestive tract of the ocean sunfish Mola mola (L.). Although the morphology of A. contortum agrees with that of a typical endoparasitic trematode, with two relatively small suckers and no large holdfasts, this parasite is normally ectoparasitic. The main objective of this paper is to explore this peculiar host-parasite relationship.MethodsA total of 106 ocean sunfish were examined for the presence of A. contortum. The oropharyngeal chamber (gills and pharynx) and the digestive tract were analysed. As the previous descriptions of this species seem to be based on contracted specimens, for the morphological study the parasites were killed using two methods: with hot 70 % ethanol (with relaxed bodies) and with 70 % ethanol at room temperature (with contracted bodies). For histological studies, samples from fresh fish with parasitised left gills, pharynx and digestive tract were fixed in buffered 10 % formalin. For molecular studies the 18S, 28S and ITS-2 sequences were provided and compared with the available data in GenBank®.ResultsNew information on the morphology of A. contortum and on the parasite-related response and pathological alterations in the host are given. New diagnostic traits for some structures are provided: e.g. tegumental papillae of the forebody with apical digitiform swellings and mouth surrounded by a circum-oral crown of simple papillae. The length of the ventral sucker peduncle and the position of the vitellarium were found to be associated with the contraction degree of the specimen. Immature individuals of this species are described for the first time. An intense proliferative inflammatory response of host gill and pharynx epithelium at the host-parasite interface was detected and parasites became partially covered by overgrowths of host tissues.ConclusionsThe induction of prominent histological alterations associated with A. contortum seems to be an adaptation to the external environment, an unusual location for trematodes.

Optimization of Factors Affecting In vitro Establishment, Ex vitro Rooting and Hardening for Commercial Scale Multiplication of Silk Banana (Musa AAB)

Factors concerning aseptic culture establishment and hardening were studied in detail in choicest Silk Banana. Effect of size of sucker (small, medium and large), carbon concentration (10, 20 and 30 g/l), season of initiation (wet and dry) and pre-treatments such as segmentation and incision to the explants were studied during initiation. Further, hardening related factors such as substrates used for primary and secondary hardening, nursery nutrition (source and frequency of application) and pre-treatments for ex vitro rooting were also studied. Results revealed that small suckers were most suited for initiations with the least contamination, maximum establishment and higher percentage of greening. Lower concentration of sucrose, though delayed greening, resulted in 100 % establishment of explants. Initiations performed during the drier period were completely free from the fungal contamination and showed less bacterial contamination than those performed during the rainy season. Segmentation of explant into four parts during first subculture supported maximum shoot proliferation by overcoming apical dominance. Coir pith was observed to be the most congenial substrate during primary hardening, whereas coir pith alone or sand: red earth: coir pith (1:1:1) supported superior performance of plantlets during secondary hardening. Single application of mono ammonium phosphate improved growth of plantlets during secondary hardening. Pre-treatment with mono ammonium phosphate gave the best response in terms of rooting and hardening of un-rooted micro-shoots. Thus, the discussed methodology could help the industries to take up commercial scale propagation of Silk Banana.

Development of a small sucker manipulator for underwater surgery support.

WaFLES (Water-Filled LaparoEndoscopic Surgery) is an operative method suggested by Igarashi et al., which has several advantages, such as, preventing the drying of inner organs, and being able to use ultrasound devices for real time monitoring. However, grasping of inner organs with usual forceps for move and incision purpose is difficult. Therefore our ultimate goal is to develop a small sucker manipulator for WaFLES support. Experiments were conducted to explore suitable suction cups for underwater application, and suitable structure (cup-to-cup distance, elasticity of binding material, layouts of multiple cups) for a multiple-cup assembly, in terms of adsorption force and tolerance to sideslip. Experiment results showed that 1) the shape of each single suction cup for the underwater application was identified; 2) the structure of the multiple-cup assembly affects the adsorption force and tolerance to sideslip.

A new species of Saturnius Manter, 1969 (Digenea: Hemiuridae) from Mediterranean mullet (Teleostei: Mugilidae)

A new hemiurid digenean, Saturnius gibsoni n. sp., is described from the stomach lining of Mugil cephalus L. off Oran, Mediterranean coast of Algeria. Characteristic morphological features of the new species include small size of the body which is comprised of six pseudosegments, small ventral sucker, weakly developed mound-shaped flange at the level of the ventral sucker, and eggs being large in relation to the size of the body. Saturnius gibsoni n. sp. resembles S. minutus Blasco-Costa, Pankov, Gibson, Balbuena, Raga, Sarabeev & Kostadinova, 2006 and two unidentified Saturnius spp. in the small size of the body and most metrical features. However, in spite of the presence of five transverse septa resulting in six pseudosegments and the range overlap of some metrical features, the ventral sucker in S. minutus is much larger, the ventral sucker muscular flange is more prominent, the last pseudosegment is narrower in relation to body width and more rounded, and the eggs are smaller (mean 21 × 10 vs 25 × 12 μm). Furthermore, the partial sequences of the 28S rRNA gene region (domains D1-D3; 1,195 nt) obtained from two isolates of S. gibsoni n. sp. differed by 11 nt (0.9%) from that of S. minutus. Both unidentified forms of Saturnius are clearly distinguishable from S. gibsoni n. sp. by the presence of six stout, transverse muscular septa, forming seven pseudosegments (vs five septa forming six pseudosegments). Bayesian inference analysis of partial 28S rDNA sequences based on a total of 15 species from the families Hemiuridae and Lecithasteridae depicted the Bunocotylinae Dollfus, 1950 as a strongly supported basal clade, with Bunocotyle progenetica (Markowski, 1936) as the closest sister taxon to Saturnius spp.

Performance and scaling of a novel locomotor structure: adhesive capacity of climbing gobiid fishes

Many species of gobiid fishes adhere to surfaces using a sucker formed from fusion of the pelvic fins. Juveniles of many amphidromous species use this pelvic sucker to scale waterfalls during migrations to upstream habitats after an oceanic larval phase. However, adults may still use suckers to re-scale waterfalls if displaced. If attachment force is proportional to sucker area and if growth of the sucker is isometric, then increases in the forces that climbing fish must resist might outpace adhesive capacity, causing climbing performance to decline through ontogeny. To test for such trends, we measured pressure differentials and adhesive suction forces generated by the pelvic sucker across wide size ranges in six goby species, including climbing and non-climbing taxa. Suction was achieved via two distinct growth strategies: (1) small suckers with isometric (or negatively allometric) scaling among climbing gobies and (2) large suckers with positively allometric growth in non-climbing gobies. Species using the first strategy show a high baseline of adhesive capacity that may aid climbing performance throughout ontogeny, with pressure differentials and suction forces much greater than expected if adhesion were a passive function of sucker area. In contrast, large suckers possessed by non-climbing species may help compensate for reduced pressure differentials, thereby producing suction sufficient to support body weight. Climbing Sicyopterus species also use oral suckers during climbing waterfalls, and these exhibited scaling patterns similar to those for pelvic suckers. However, oral suction force was considerably lower than that for pelvic suckers, reducing the ability for these fish to attach to substrates by the oral sucker alone.

CLIMBING GOBIES HAVE SMALL BUT POWERFUL SUCKERS

Scaling waterfalls through torrents of water would be an impressive feat for any creature, but for tiny juvenile gobies returning to their homes in the upper reaches of island streams, it's an inevitable rite of passage. Many goby larvae are washed out to sea soon after hatching, so species that reside in the upper reaches of streams have no choice but to scale obstacles in their path on the return journey. However, the youngsters are well prepared for this trial. They have a sucker formed from fused pelvic fins on their undersides that they use for climbing. Adult fish also face the risk of being washed downstream. However, they seem to climb less than youngsters. According to Takashi Maie from Clemson University, USA, the adults' suckers may not adhere strongly enough to support the larger fish's mass, as their suckers only increase in size in proportion to their body length, whereas their mass increases much more. Intrigued by this possibility, Maie realised that he would have to measure the adhesive pressure and sucker suction force from fish with different lifestyles and of different sizes to find out how their adhesion varies as they grow. Teaming up with Heiko Schoenfuss from St Cloud State University, USA, and Richard Blob from Clemson, Maie travelled to the Hilo field station of the Division of Aquatic Resources, Hawai‘i, to measure how tightly goby suckers fasten to surfaces (p. 3925).Scrambling up waterfalls to the gobies' homes and donning wetsuits to snorkel and catch the fish, the trio successfully collected five species of climbing fish ranging in size from 0.1 to 15 g, in addition to one non-climbing species collected at low altitude. Back at the field station, the team gently anaesthetised the fish and lightly touched their suckers to a simulated climbing surface. The suckers immediately formed a seal and stuck on. Measuring the pressure in the cavity between the sucker and surface at inclinations ranging from 45 deg to over 90 deg and comparing the sucker sizes and adhesive forces between the two lifestyles (climbing and non-climbing), Maie and his colleagues noticed that the non-climbers' suckers increased in size much more rapidly than if they were growing in proportion to the rest of the body, whereas the climbers' suckers only grew in proportion of the rest of their bodies. The non-climbers' suckers were relatively large for their size.Next the team measured the sucker's adhesion as the fish ascended waterfalls. After building a gently cascading simulated miniwaterfall, Maie drilled a hole in the surface, inserted a pressure transducer to measure the fish's adhesion and waited for the animals to pass over the pressure transducer as they ascended the slope. Comparing the climbers' suction force with the passive force that they had measured when the fish were anaesthetised, Maie realised that the active suction forces were more than twice as great as the passive, and were sufficient to bear more than twice the fish's mass. In contrast, the non-climbers' adhesion forces were much weaker than those of their climbing cousins, despite the relatively large size of their suckers. The team suspects that the non-climbers enlarged suckers may compensate for their weaker adhesion.Having shown that climbing gobies have smaller suckers than their non-climbing cousins but that the climbers' suction is much stronger, Maie explains that the climbers actively expand their suckers while in contact with the surface to increase their suction, and he and his colleagues are keen to find out how the muscles and ray structures that support the sucker alter with age to help growing gobies get a grip.

A New Genus and Species of Proteocephalidean Tapeworm (Cestoda) From Pangasius larnaudii (Siluriformes: Pangasiidae) In Southeast Asia

A new proteocephalidean cestode is described from spot pangasius, Pangasius larnaudii (Siluriformes: Pangasiidae), from Tonle Sap Lake in Cambodia and a new genus, Pangasiocestus , is proposed to accommodate it. The genus is placed in the Gangesiinae because its scolex possesses a large rostellum-like apical organ and its genital organs (testes, ovary, vitellarium, and uterus) are situated in the medulla, with some vitelline follicles paramuscular. Pangasiocestus romani n. gen. and n. sp., the type and only species of the new genus, is characterized mainly by its rosette-like scolex composed of 4 lobes bearing a small sucker in their center, and the apical part with a large, discoidal, rostellum-like apical organ devoid of hooks, by weakly developed inner longitudinal musculature formed by very few isolated muscle fibers, uneven size of testes in immature and mature proglottids, with lateral testes smaller and more dense than median ones, by very narrow lateral bands of vitelline follicles, formed usually by single follicles, and by the vagina anterior to the cirrus sac. This is the first proteocephalidean cestode from a pangasiid catfish identified to the species level (proteocephalidean cestodes from 3 Pangasius spp. reported in an unpublished account from Vietnam, misidentified as Proteocephalus osculatus (Goeze, 1782) [ = Glanitaenia osculata ], are not considered).

Population Distribution and Density of Pentalonia nigronervosa (Hemiptera: Aphididae) Within Banana Mats: Influence of Plant Age and Height on Sampling and Management

The banana aphid, Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae), is the most economically important pest of banana (Musa spp.) fields in Hawaii. Recently, there has been a concerted effort in Hawaii to learn more about the biology and ecology of this pest. However, limited work has been directed at determining the distribution of P. nigronervosa in banana fields and developing an integrated pest management plan. Therefore, a survey was conducted in banana fields throughout the Hawaiian Islands to determine the distribution and density of P. nigronervosa within banana mats from plants of different stages. Another aim was to determine whether the presence of ants on banana plants could be used as a reliable indicator of aphid infestations. Results of the survey showed that plants < or = 1.5 m (small sucker) in height contain the highest aphid populations per meter in plant height and that mother plants (> or = 2.5 m) had the lowest aphid counts and rate of infestation compared with small and intermediate suckers (> 1.5 < 2.5 m). More specifically, aphid population was reduced by approximately 12 aphids for every meter increase in plant height and that aphids are rarely found > or = 2.5 m within the plant canopy. Although there was an increase likelihood of finding ants on banana plants with higher aphid densities, results suggest that ants would be present on plants in the absence of aphids. Implications of these and other findings with respect to sampling and managing P. nigronervosa and associated Banana bunchy top virus are discussed.

Proctocaecum blairi sp. nov. (Digenea, Cryptogonimidae) from the freshwater crocodile, Crocodylus johnstoni, in Northern Territory, Australia

AbstractProctocaecum blairi sp. nov. is described from specimens found in the intestine of an Australian freshwater crocodile, Crocodylus johnstoni, from Northern Territory, Australia. The most important diagnostic features of the new species are the body proportions and size, the position of the pharynx (relative length of the prepharynx and oesophagus), the relative length and position of the vitelline fields, and the number, shape and size of the circumoral spines. The new species is morphologically most similar to Proctocaecum atae, P. elongatum, P. crocodili, P. gairhei and Acanthostomum slusarskii. It differs from all of these species in having a much longer prepharynx, and differs from both P. atae and P. crocodili in having a much longer body and posteriorly situated vitelline fields. Proctocaecum blairi sp. nov. differs from P. elongatum in having a shorter body, a greater forebody to hindbody ratio, a much smaller ventral sucker, and a higher number of circumoral spines (23 vs 21 in P. elongatum). The new species differs from P. gairhei in possessing a much larger body length:width ratio and an ovary separated from the anterior testis by a seminal receptacle. Acanthostomum slusarskii lacks a gonotyl and has fewer circumoral spines than the new species. Proctocaecum blairi sp. nov. is the third species of Proctocaecum and the fourth cryptogonimid species known from crocodiles in Australia.

Re-evaluation of the species composition of Bashkirovitrema Skrjabin, 1944 (Digenea: Echinostomatidae), with the description of two new species of this genus and the proposal of Kostadinovatrema novaeguiniense n. g., n. sp.

A comparison of specimens previously identified as Bashkirovitrema incrassatum (Diesing, 1850) from the African or cape clawless otter Aonyx capensis, and the speckle-throated or spotted-throated otter Hydrictis maculicollis from the Old World with specimens and descriptions of B. incrassatum from the New World showed that those from Africa (Bashkirovitrema africanum n. sp.) had a more extensive distribution of the vitelline fields than either B. canadense n. sp. from the northern river otter Lontra canadensis and the American mink Neovison vison (North America) and B. incrassatum from the Neotropical river otter Lontra longicaudis (South America). B. africanum n. sp. further differs from B. canadense n. sp. by having a smaller body, shorter forebody, smaller oral sucker, longer cirrus, shorter intertesticular space, shorter post-testicular space and longer eggs. B. canadense n. sp. can be distinguished from B. incrassatum by having a longer body, longer forebody, smaller sucker ratio, smaller testes, greater distance between the ventral sucker and the ovary, shorter cirrus-sac, longer post-testicular space and narrower eggs. B. africanum n. sp. differs from B. incrassatum by having a smaller ventral sucker, larger ovary, shorter cirrus-sac, smaller intertesticular space, larger post-testicular space and longer eggs that are not as wide. Kostadinovatrema n. g., as represented by K. novaeguiniense n. sp., can be separated from species of Bashkirovitrema Skrjabin, 1944 by having a wider body width to length profile, a head collar that is narrower than the forebody and armed with 33 rather than 27 collar spines, an ovary that is further removed anteriorly from the testes, and a dorso-ventrally flattened hindbody that is nearly as broad as the forebody. The new genus differs from Hypoderaeum Dietz, 1909 and Moliniella Hübner, 1939 by having 33 head collar spines.

Rapid seedlings regeneration from seeds and vegetative propagation with sucker and rhizome of Eremospatha macrocarpa (Mann & Wendl.) Wendl and Laccosperma secundiflorum (P. Beauv.) Kuntze

To develop efficient seedling production methods for Laccosperma secundiflorum and Eremospatha macrocarpa, a study was conducted to examine regeneration using offsets combined with several physical and chemical treatments of seeds. Offsets categorized into small, medium and large diameters, were planted in three conditions: shaded and open nursery, and greenhouse. We tested sucker from E. macrocarpa, and sucker and rhizome from L. secundiflorum. For both species, high viability percentage (ranging from 55% to 100%) were observed for small and medium suckers planted in shaded nursery and greenhouse, against less than 49% for sucker planted in open nursery. The mean seedling emergence times were estimated to 84, 77 and 75 days after planting (DAP) for small, medium and large sucker of L. secundiflorum, respectively under open nursery condition, and 76, 75, 95 DAP for small, medium and large suckers of the same species, respectively in shaded condition. Greenhouse has a significant positive effect on E. macrocarpa seedlings emergence time. For this species, the mean seedling emergence times were estimated to 43 DAP for small sucker and 76, 93 DAP for medium and large suckers. No seedling was obtained from rhizome planted in all the growing conditions tested. Concerning seed dormancy breaking, germination percentages and rates were determined for 13 treatments. The best treatments were pre-soaking unscarified seeds for 4 days in 1.01 g l −1 and 0.10 g l −1 KNO 3, with 79% and 68% of germination, respectively and in 3.46 × 10 −3 g l −1 GA 3 for 68% of germination. These methods are suggested to improve germination of L. secundiflorum seeds. Successful and recommended methods for E. macrocarpa are pre-soaking scarified seeds in 3.46 × 10 −3 g l −1 and 3.46 × 10 −4 g l −1 GA 3, 96% and 94% of germination, respectively. Dormancy, probably a combination of mechanical and chemical dormancy, is present in the two species.

Effects of soil temperature and time of decapitation on sucker initiation of intact Populus tremuloides root systems

In a growth chamber experiment, root suckering of aspen (Populus tremuloides Michx.) was assessed in relation to timing of cutting and soil temperature. Aspen seedlings were grown in large pots for 3 years before experimentation. In a 2×2 factorial experiment, 3-year-old seedlings were cut at the end of the dormant period or after leaf flush and grown at two soil temperatures (8 or 20°C) for 39 days. Root systems were evaluated for suckering response and carbohydrate reserve status. There were no differences between the two soil temperatures and times of cut in the number of sucker buds initiated on the roots, but the number of buds that developed into suckers was much greater at 20°C. Cutting the dormant seedlings delayed suckering by nearly a week, resulting in smaller suckers at the time of harvest. However, cutting the seedlings when dormant produced almost twice the number of suckers than when cutting occurred after leaf-out. Total non-structural carbohydrates (TNC) of roots declined from 35.6% of dry weight at the end of the dormant season to 21.6% at the time of leaf-out, but there were no differences between the soil temperature and timing of cut treatments. After the 39 day growth period, root systems had 7% lower root TNC in the 20°C treatment than in the 8°C treatment, likely to support the development of the emerging suckers and higher respiration demands.

Rhopalobdella japonica n. gen., n. sp. (Hirudinea, Piscicolidae) from Dasyatis akajei (Chondrichthyes: Dasyatididae) in the northwestern Pacific.

A new genus and species of piscicolid leech in the Platybdellinae inhabits the oral cavity of Dasyatis akajei in the northwestern Pacific Ocean near Tanabe, Japan. The genus Rhopalobdella n. gen. is characterized externally by very small oral and caudal suckers and a smooth body that is widest just posterior to the clitellum. Eyespots and ocelli are lacking. The coelom is spacious with large segmental connecting sinuses between dorsal and ventral sinuses. There are 5 pairs of testisacs, an unusually extensive epididymis, and a very large bursa. Conducting tissue is absent. There are 2 pairs of esophageal diverticula and very well developed nephridia. Rhopalobdella japonica n. gen. n. sp. is characterized by a urosome that tapers strongly to the caudal sucker and by a single gonopore; the common oviduct opens into the posterior portion of the bursa. The coelomic and excretory systems resemble Aestabdella, but in other respects the genera are quite different. This is the first marine leech reported from rays in the northwestern Pacific.