Blunt Apex Research Articles

A new species of the genus Perotripus (Crustacea: Amphipoda: Caprellidae) from Korea

From an examination of caprellid specimens collected from Korea, we found a new species belonging to the genus Perotripus. This new species is clearly distinguished from two previously recorded species, P. brevis and P. keablei, in having an acute projection and blunt apex of distal segment of pereopod 5. This genus Perotripus is reported from Korea for the first time. We described it with figures in detail. As a result, Korean caprellid fauna consists of 35 species in seven genera.

Comparative anatomical features of Prosopis cineraria (L.) Druce and Prosopis juliflora (Sw.) DC (Mimosaceae)

A comparative study of the leaflets of two domestic species of Prosopis is reported. Both the species, Prosopis cineraria and Prosopis juliflora, have been reported to possess antibacterial, antifungal, anti-inflammatory and the most concerning anticancer properties. In view of its medicinal importance and taxonomic confusion, the individual morphological and histological characteristics of these two species have been described through certain parameters such as structural profile of the leaflets, stomatal morphology, venation pattern, petiolule and vascular system of the rachis. Evaluation of the fresh and anatomical sections of the leaves of both species was carried out to determine its macro- and microscopical (histological) characters. The studies indicated the presence of bipinnately compound leaf, an entire margin, apiculate apex, obtuse base, reticulate venation, thick and straight anticlinal walled epidermal cells, prismatic type of calcium oxalate crystals in the mesophyll tissue, dense deposition of tannin content and paracytic type stomata in the P. cineraria, whereas P. juliflora has a bipinnately compound leaf with an entire margin, blunt apex, round base, reticulate venation, thick and straight walled epidermal cells, large mucilage cavities in the mesophyll tissue and paracytic type stomata. The above findings provided referential information for identification of the species P. cineraria and P. juliflora. Key words: Prosopis cineraria, Prosopis juliflora, sacred tree, Vanni

Silica bodies and their systematic implications in Pteridaceae (Pteridophyta)

Wet ashing was used to study the occurrence of silica bodies in the fern family Pteridaceae. They were recovered in 48 of the 77 species examined. Silica bodies of Pteridaceae are elongate, ranging from 90–1320 × 5–40 µm, linear to elliptic, with blunt or acute apices and smooth to sinuate sides. All previous records of silica bodies and venuloid idioblasts among Pteridaceae that were examined were confirmed by the results of this study, corroborating our assumptions regarding the presence of silica bodies. In contrast, assumptions regarding the absence of silica bodies were incorrect; in many species of Adiantum, for example, silica bodies are present but cannot be seen with the naked eye. Farris optimization demonstrates that the distribution of epidermal silica bodies is homoplastic within Pteridaceae, but that they act as a potential synapomorphies for several different groups within the family. These include the adiantoid clade: Adiantum and the 11 vittaroid genera, and in some pteridoid fern clades such as the sister pair Onychium and Actiniopteris and the genus Pityrogramma. They are also present in Pterozonium brevifrons and some species of the polyphyletic genus Pteris. Among cheilanthoid ferns, they were found in Mildella intramarginalis and two species of Aspidotis. Morphology of silica bodies differs between major lineages, reflecting their independent origins. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 422–435.

Scanning electron microscopic study on the structure of the lingual papillae of the Saanen goat

The morphology of lingual papillae of the ten male mature Saanen goats (11 months old, approximately 42 kg in weight and of a known pedigree) was examined by scanning electron microscopy. Tissues were taken from the dorsal and ventral surfaces of the apex, body and root of the tongue, and were prepared accordingly and observed under the scanning electron microscope. On the dorsal and ventro-lateral surfaces of the lingual mucosa, three types of mechanical papillae (filiform, lenticular, and conical) and two types of gustatory papillae (vallate and fungiform) were observed. The structure and density of the filiform papillae differentiated on the anterior, posterior and ventro-lateral aspects of the tongue. Two types of lenticular papillae, both possessing a prominent surrounding papillary groove, were determined. The pyramidal-shaped type I lenticular papilla had a pointed apex while the round-shaped type II lenticular papilla possessed a blunt apex. Certain number of the type I lenticular papillae had double apices. The larger conical papillae were hollow structures, differing structurally from the filiform papillae with their larger size, a tip without projections and lack of the secondary papillae. The vallate papillae were present on both rims of the torus linguae, were encircled by a prominent gustatory furrow which was also surrounded by a thick annular fold. The fungiform papillae were scattered among the filiform papillae in the anterior two-thirds of the dorsal and lateral surfaces, and each of them was highly protected by surrounding filiform papillae, yet encircled by a papillary groove. Our findings indicate that Saanen goat have profuse distribution of papillae on the tongue displaying morphological features characteristic of mechanical function.

Ulmus leaves and fruits from the Early–Middle Eocene of northwestern North America: systematics and implications for character evolution within Ulmaceae

Leaves and fruits of Ulmus from the Early–Middle Eocene of British Columbia and Washington are assigned to two species. Ulmus okanaganensis sp.nov. is based on leaves attached to flowering and fruiting twigs and isolated leaves and fruits. Leaves display a polymorphism ranging from large leaves with compound teeth with a blunt apex to small ones with simple teeth resembling those of Zelkova. In extant Ulmus, sucker-shoot leaves, elongation-shoot leaves, and leaves on short annual branches often display a very similar polymorphism. In the fossil, flowers are arranged in fascicles having short pedicels. Fascicles are formed in the axils of leaves of current-year shoots and appear together with the leaves. This is uncommon in modern species of Ulmus, where leaves appear either in spring on previous-year shoots or in autumn in the axils of leaves of current-year shoots. Fruits of U. okanaganensis are samaras with extremely reduced or absent wings. Unwinged fruits of modern Ulmus are typically ciliate along the margin of the endocarp and the persistent styles but only a single fruit of U. okanaganensis has been found preserving hairs. The small, shallowly lobed perianth is situated below the endocarp. A second type of foliage is assigned to Ulmus chuchuanus (Berry) LaMotte. This foliage is wider than that of U. okanaganensis and has more densely spaced secondary veins. It also has characteristic compound teeth with primary and subsidiary teeth displaying conspicuously different orientations. Leaves of U. chuchuanus co-occur with a second type of fruit but have not been found in attachment. These fruits are larger than in U. okanaganensis, with a narrow wing, persistent styles, and a large and wide persistent perianth that tapers abruptly into the perianth tube. A cladistic analysis suggests that U. okanaganensis is nested within the subgenus Ulmus, which is a paraphyletic grade basal to the subgenus Oreoptelea. Ulmus chuchuanus foliage shows affinities to the subgenus Ulmus, while the associated fruits display affinities to the subgenus Oreoptelea.

Occurrence of the Latero-subapical Labial Sensillum in Borysthenes maculata and Andes marmorata (Hemiptera: Fulgoromorpha: Cixiidae)

A peg-like structure, found on each lateral side of the distal segment of the labium, close to the labial apex, in two cixiid planthopper species Borysthenes maculata (Matsumura) and Andes marmorata (Uhler) (Hemiptera: Fulgoromorpha: Cixiidae), is reported for the first time with scanning electron micrograph. It is an elongate, peg-like structure hidden in an elongate, narrow, shallow cavity parallel to the longitudinal axis of the labium. In B. maculata, the peg, being about 82 μm proximal to the labial tip, is about 27.6–29.4 μm long and 6.8–7.6 μm wide with a blunt apex. The peg in A. marmorata, being about 60 μm proximal to the labial tip, is distinctly short and narrow and is about 10.2–12.0 μm long, tapering gradually from a basal width of about 2.7 μm to a blunt apex of 0.88 μm wide. The structure, being two in number (one at each lateral side of the labium), is present in both male and female adults. Light microscopic survey shows that this structure is common in cixiid species. It also is present in species of the relatively primitive fulgoromorphan families, e.g., Achilixiidae, Delphacidae and Achilidae, but it is absent in other relatively advanced fulgoromorphan families, e.g., Fulgoridae, Dictyopharidae, Lophopidae and Eurybrachidae. It is regarded as a homologous structure with the previously described ‘multi-lobed sensillum’ in Delphacidae and is herein named ‘latero-subapical labial sensillum’. The function of the structure is not clear but it seems likely that it is a sensory structure. The phylogenetic significance of this structure is briefly discussed.

Diabrotica virgifera

<i>Diabrotica virgifera</i>

First Occurrence of Downy Mildew on Boxleaf Veronica Caused by Peronospora grisea in Italy.

Boxleaf veronica (Hebe buxifolia (Benth.) Cockayne & Allan), native to New Zealand, is an annual or perennial shrub widely cultivated in Mediterranean zones. During late spring 2003, after seasonably wet and cool weather, a downy mildew epidemic occurred on potted, overhead irrigated, 1-year-old seedlings at a commercial nursery in eastern Sicily (southern Italy). Infections affected boxleaf veronica at first, but spread to variegated boxleaf (H. buxifolia cv. variegata). Initial symptoms on the upper side of leaves were small, gray brown patches that gradually spread, eventually resulting in necrosis in the center of infected areas. At that point, brown patches were evident on both sides of the leaves. Lesions on the lower leaf surface became covered with a fairly dense, pale gray-to-brown layer of conidia and conidiophores. As the disease progressed, these spots coalesced into large and conspicuous brown lesions. The youngest, most succulent shoots withered and died. The large brown lesions on the leaves were disfiguring and affected 95 to 100% of plants in the nursery. All diseased nursery stock had to be discarded. Oospores were not observed in leaf tissues. The fungus recovered from leaves with abundant gray brown sporulation was identified as Peronospora grisea (Unger) Unger. Microscopic observations revealed conidiophores that branched dichotomously five to seven times with branch ends 6 to 10 × 2 to 3 μm, slightly curved, and tapered to a blunt apex. Hyaline conidia were ellipsoid, brownish when mature, and measured 23 to 27 × 15 to 18 μm (mean = 25.2 × 17.1 μm), falling within the range of those reported for P. grisea (1). Pathogenicity was confirmed by inoculating 10 1-yr-old seedlings (10 cm tall) by gently pressing infected leaves with abundant sporulation onto healthy leaves and maintaining inoculated plants in a humid chamber at 21°C. An equal number of noninoculated plants served as controls. After 9 to 11 days, symptoms similar to those originally observed developed onto inoculated plants, and after 12 to 15 days, grayish mildew grew on leaves. Microscopic examination of the developing mycelium confirmed that leaves were infected with P. grisea. Uninoculated control plants did not develop any symptoms. The disease was also confirmed in this way on variegated boxleaf veronica (H. buxifolia cv. variegata). Downy mildew of Hebe spp. has been recorded in New Zealand, Britain, France, Germany, and more recently, West Sussex (2). Heavy rainfall during the spring of 2003 in eastern Sicily could have favored disease development. To our knowledge, this is the first report of downy mildew of boxleaf veronica and variegated boxleaf veronica caused by P. grisea in Italy.

Practical use of a carbon nanotube attached to a blunt apex in an atomic force microscope

A carbon nanotube (CNT) was successfully attached to a base probe with a blunt apex and subsequently used as a probe for an atomic force microscope (AFM). This setup demonstrates high spatial resolution properties, plus an advantage: we were able to readily identify the loss of the CNT from the end of the probe by the resultant sudden drop in resolution. This design of probe is expected to feature yet another advantage: that of relative immunity to accidental collision compared to a CNT attached to a commercially available sharp tip. We also discuss the problems specific to CNT-attached probes, which are carbon contamination of the sample surface and artifact images formed at the edge of pit structures. We demonstrate that carbon contamination can be suppressed by a rubbing procedure before the scanning use, and that pit artifacts can be eliminated by optimizing the CNT length.

A New Species of the Genus Propedies Hebard (Acridoidea: Acrididae: Melanoplinae) from Northern Argentina

A New Species of the Genus Propedies Hebard (Acridoidea: Acrididae: Melanoplinae) from Northern Argentina

Early radiographic diagnosis of apical root resorption during orthodontic treatment: a study of maxillary incisors.

The purpose of this study was to evaluate the sensitivity of digital radiographs for detection of (i) simulated root resorption cavities in an experimental model and (ii) orthodontically-induced apical root resorption in vivo. The severity of root resorption after 3 and 6 months treatment was studied in relation to root form. The experimental study cavities, drilled in mandibular roots in a dry skull, were recorded in conventional and digital radiographs. In vivo root resorption was evaluated on digital radiographs of 92 maxillary incisors after 3 and 6 months treatment with fixed appliances. The results showed a similar sensitivity for the two methods. Sensitivity increased significantly with cavity size. After 3 months apical root resorption was detected in only a few teeth. The number had increased significantly after 6 months. There was a higher degree of root resorption in teeth with blunt and pipette-shaped apices. In such teeth a 3-month radiographic control is recommended.

Observations on the external morphology and vasculature of a fetal heart of the bowhead whale, Balaena mysticetus

Background Specialized demands within the aquatic environment for over some 60 million years have shaped unique morphological expressions in the whales, dolphins, and porpoises (Cetacea). Detailed consideration of these features, particularly in the great whales, has often been constrained by difficulties in securing adequate specimens for study. We had the opportunity to examine external heart morphology in a rarely obtained and prepared specimen from the bowhead whale, Balaena mysticetus. Methods The external morphology and in situ relations of a formalin-perfused heart were examined grossly in a near-term bowhead fetus. Latex injections assisted visualization of coronary vasculature. Magnetic resonance imaging was used to clarify heart positioning within the thoracic cavity in two younger (early and mid-gestational) intact fetuses. Results The heart was globular in form, with a blunt apex and wide base; it was laterally broad relative to height yet considerably compressed between nearly planar atrial (diaphragmatic) and auricular (sternocostal) surfaces. The heart constituted 0.01 of body mass in the near-term fetus. Within the thoracic cavity, the heart tilted forward on its long axis, placing the great basal vessels in the region of the thoracic inlet. The aorta extended forward from mid-base in parallel with the pulmonary trunk, arched sharply to the left, producing in succession the brachiocephalic trunk, left common carotid artery, and the left subclavian artery. Bifurcation of the brachiocephalic trunk yielded the right common carotid and right subclavian arteries. The distal portion of the aortic arch was linked to the pulmonary trunk via the ductus arteriosus. The aorta then swung caudally over the heart base, descending beneath the bodies of the thoracic vertebrae. The ascending aorta featured three bulbous sinuses immediately distal to the three semilunar cusps of the aortic valve. Originating along the distal boundaries of the left and right sinuses were the left and right coronary arteries. The arteries were similar in size and, because each sent contributions along their respective coronary and interventricular grooves, the heart can be described as bilateral relative to arterial supply. Anastomoses were common within and between the two arteries. Venous return from the heart was comprised of the great, middle, and right cardiac veins, all three converging in the coronary sinus. The right cardiac vein also included tributaries that emptied directly into the right atrium. Conclusions External heart morphology in the fetal bowhead whale examined was distinguished by a laterally broad conformation with significant compression between its cranial and caudal surfaces. Aortic bulb configuration in combination with an expandable aortic arch may support blood service to the heart during diastole. Vascular service to the heart featured a complex vessel network with extensive intraarterial and intravenous anastomoses that enable many alternate blood perfusion pathways and may be adaptive to water-column-pressure fluctuations experienced by a large diving mammal. Anat. Rec. 247:556–581, 1997. © 1997 Wiley-Liss, Inc.

Observations on the external morphology and vasculature of a fetal heart of the bowhead whale, Balaena mysticetus.

Specialized demands within the aquatic environment for over some 60 million years have shaped unique morphological expressions in the whales, dolphins, and porpoises (Cetacea). Detailed consideration of these features, particularly in the great whales, has often been constrained by difficulties in securing adequate specimens for study. We had the opportunity to examine external heart morphology in a rarely obtained and prepared specimen from the bowhead whale, Balaena mysticetus. The external morphology and in situ relations of a formalin-perfused heart were examined grossly in a near-term bowhead fetus. Latex injections assisted visualization of coronary vasculature. Magnetic resonance imaging was used to clarify heart positioning within the thoracic cavity in two younger (early and mid-gestational) intact fetuses. The heart was globular in form, with a blunt apex and wide base; it was laterally broad relative to height yet considerably compressed between nearly planar atrial (diaphragmatic) and auricular (sternocostal) surfaces. The heart constituted 0.01 of body mass in the near-term fetus. Within the thoracic cavity, the heart tilted forward on its long axis, placing the great basal vessels in the region of the thoracic inlet. The aorta extended forward from mid-base in parallel with the pulmonary trunk, arched sharply to the left, producing in succession the brachiocephalic trunk, left common carotid artery, and the left subclavian artery. Bifurcation of the brachiocephalic trunk yielded the right common carotid and right subclavian arteries. The distal portion of the aortic arch was linked to the pulmonary trunk via the ductus arteriosus. The aorta then swung caudally over the heart base, descending beneath the bodies of the thoracic vertebrae. The ascending aorta featured three bulbous sinuses immediately distal to the three semilunar cusps of the aortic valve. Originating along the distal boundaries of the left and right sinuses were the left and right coronary arteries. The arteries were similar in size and, because each sent contributions along their respective coronary and interventricular grooves, the heart can be described as bilateral relative to arterial supply. Anastomoses were common within and between the two arteries. Venous return from the heart was comprised of the great, middle, and right cardiac veins, all three converging in the coronary sinus. The right cardiac vein also included tributaries that emptied directly into the right atrium. External heart morphology in the fetal bowhead whale examined was distinguished by a laterally broad conformation with significant compression between its cranial and caudal surfaces. Aortic bulb configuration in combination with an expandable aortic arch may support blood service to the heart during diastole. Vascular service to the heart featured a complex vessel network with extensive intraarterial and intravenous anastomoses that enable many alternate blood perfusion pathways and may be adaptive to water-column-pressure fluctuations experienced by a large diving mammal.

Characterization of the Blunt Leaf Apex (bla) Trait in Cucumber

A further characterization of the cucumber (Cucumis sativus L.) mutant `Wisconsin SMR-18' bla (blunt leaf apex) revealed a new character associated with the previously described leaf phenotype. The attachment of the blade to the petiole of bla plants is flat across, as opposed to the cordate or indented attachment in the wild-type `Wisconsin SMR-18' plants. The new character (truncate leaf base) was easier to score and becomes distinctive earlier in development than previously described leaf apex characters. It was expressed consistently in homozygous bla plants. Segregation analysis of 1159 F2 seedlings arising from self-pollinated `Wisconsin SMR-18' × `Wisconsin SMR-18' bla F1 plants suggested that the leaf base and leaf apex character were controlled by a single locus or two tightly linked ones with a maximum distance between the two of 0.03 cM. In a field study of growth and fitness characteristics, the two genotypes did not differ significantly for flower or fruit count. The similar flowering and fruiting characteristics, along with the reliable early occurring truncate character, likely will make the two genotypes useful for pollination and gene movement studies.

Carinachitiids, hexangulaconulariids, andPunctatus: problematic metazoans from the Early Cambrian of South China

Carinachitiids, hexangulaconulariids, andPunctatusare distinctive and abundant components of early skeletal faunas from the Lower Cambrian of South China. Carinachitiids are redescribed on the basis ofCarinachites spinatusfromKuanchuanpu, Shaanxi, andC. tetrasulcatusandC. curvatornatusfrom Emei, Sichuan. Tubes of all species are characterized by pronounced quadriradial symmetry, but whereasC. spinatusandC. curvatornatusgenerally have prominent ornamentation consisting of transverse ribbing, that ofC. tetrasulcatusis much more subdued. Neither apex nor well-defined aperture is evident in any of the carinachitiids. Hexangulaconulariids are redescribed on the basis ofArthrochites emeishanensisfrom Emei andHexaconularia sichuanensisfrom Kuanchuanpu. In common with the carinachitiids, the former species shows wide morphological variability. The tubes expand rapidly from a blunt apex, bear prominent ribbing, and possess variably developed lateral grooves that impose a quasi-hexaradial symmetry.Hexaconularia sichuanensisis described from fragmentary material with prominent ribbing and well-defined lateral grooves.Punctatus emeiensishas a tapering ribbed cone, with a stellate ornamentation adapically that is replaced by longitudinal ribbing towards the aperture. Carinachitiids and hexangulaconulariids are widely regarded as related to conularids, and this proposal receives additional support here. An external abortive ?borehole in a specimen ofCarinachitesalso supports the tubicolous interpretation of these fossils. An alternative suggestion that carinachitiids and hexangulaconulariids represent the internal rachis of a sea-pen is also considered. The affinities ofPunctatusare more speculative, but the genus may be related to the other two groups. The ecology ofPunctatus, however, remains problematic.

A New Combination in Wattakaka (Asclepiadaceae)

The genus Wattakaka (Hasskarl 1857) was based on Hoya R. Br. sect. Wattakaka (Decaisne 1844), and is closely related to Dregea (Meyer 1837) a name used by J. D. Hooker (1883) in his Flora of British India. The principal differences between these two are the presence of twisted corolla-lobes and unwinged, longitudinally striate or grooved follicles with a blunt apex in Wattakaka as against corolla-lobes usually not twisted and generally variously winged (rarely unwinged but then not longitudinally striate or grooved) follicles with a conical apex in Dregea. Wattakaka has sometimes been also treated under Marsdenia R. Br. (Brown 1811) but Huber (1973) reinstated the genus Wattakaka and used W. volubilis (L.f.) Stapf for Dregea volubilis (L.f.) Benth. ex Hook.f. Recently (Rahman & Wilcock 1989) Dregea volubilis (L.f.) Benth. ex Hook.f. var. lacuna (Buch.Ham. ex Wight) Hook.f. has been transferred to Wattakaka volubilis (L.f.) Stapf var. lacuna (Hook.f.) Rahman & Wilcock. Therefore, the only remaining Indian taxon Dregea volubilis (L.f.) Benth. ex Hook.f. var. angustifolia Hook.f., which was raised to the species level first under Marsdenia and then under Dregea, needs proper placement under the genus Wattakaka. The resulting new combination is proposed.

Systematics of Udotea species (Bryopsidales, Chlorophyta) in the tropical western Atlantic

Twenty-one taxa of the genus Udotea from the tropical western Atlantic are treated. Ten new species (U. abbottiorum, U. caribaea, U. dixonii, U. dotyi, U. fibrosa, U. goreaui, U. looensis, U. luna, U. norrisii, U. unistratea) and one new variety (U. cyathiformis var. flabellifolia) are described. Udotea sublittoralis W.R. Taylor and U.infundibulum J. Agardh are reduced to formae of U. cyathiformis Decaisne. Distinguishing features of the eight pre-existing taxa are clarified, and all 21 taxa are illustrated.A cladistic analysis, with all 47 characters weighted equally, of the Udotea species from the tropical western Atlantic indicates that, although 11 of the 12 phylogenetic trees produced represent a gradation without formally recognizable groups and no major evolutionary breaks, the twelfth tree depicts four monophyletic groups and one paraphyletic group. The group possessing the most derived characters (Flabellum group) consists of the fully corticated species with blunt-tipped lateral appendages (U. dixonii, U.dotyi, U. flabellum, U. norrisii, U. occidentalis). Udotea goreaui and U. wilsonii comprise the second group (Wilsonii group) of partially corticated species with blunt appendage apices. A third group (Verticillosa group) contains those uncorticated and partially corticated species in which the lateral appendages of the stipe or blade terminate in long tapering points (U. looensis, U. luna, U. spinulosa, U. verticillosa). The uncorticated species in which appendages of the stipe end in blunt or swollen tips (U. abbottiorum, U. caribaea, U. conglutinata, U. cyathiformis, U. fibrosa) comprise a fourth group (Conglutinata group). The fifth entity (Unistratea group) consists of U. unistratea, which has a simple, unistratose, uncorticated blade and blunt stipe appendages. Although our phylogenetic analysis suggests that Udotea in the tropical western Atlantic comprises five evolutionary groups, the differences are not substantial enough to warrant formal subdivision into segregate genera. The fact that eleven of the 12 trees in the analysis were variations of a gradation (species branching off a single line extending from simple to derived) supports this interpretation. We conclude that Udotea, as currently defined, is a coherent, monophyletic unit that should be maintained as a single genus.

A new species of myxozoa, Myxobolus episquamalis sp. nov. infecting the scales of the mullet, Mugil cephalus L.

A new myxosporean, Myxobolus episquamalis sp. nov. is described from the scales of the mullet, Mugil cephalus in Japan. Lerge, flat cysts developed on the surface of the apical area of the scales were formed of polysporous trophozoites which varied greatly in shape, being mostly irregularly winding, branched hypha-like bodies. Spores were oval in front view, tapering anteriorly to a blunt apex and lenticular in lateral view. Most spores were completely covered with a thick mucus envelope. Pyriform polar capsules were somewhat unequal in size and without visible filament coils. The sporoplasm contained an iodiophilous vacuole. Each valve had a nipple-shaped thickening with an opening of the polar capsule on the sutural edge at the apex and irregularly folded on the margin. Dimensions (μm) of fresh spores : length, 7.5-9.5 (8.6); width, 6.0-7.5 (6.8); thickness, 4.5-5.5 (5.1); polar capsules : length, 3.8-5.0 (4.4); width, 2.0-3.0 (2.2).

Two new genera of the family Pilumnidae (Crustacea: Decapoda: Brachyura) from Queensland, Australia

Two new genera of Pilumnidae each with a single new species are described from southeastern Queensland waters. Priapipilumnus is defined by the greatly swollen base and simple blunt apex of the male first pleopod and the concomitant posteriorly protruding, bilobed, third abdominal segment. Takedana is separable by the very short spinous anterolateral margins, the swollen branchial regions, the moderately short walking legs, and the strongly spined chelae. Actumnus pugilator is reassigned to Bathypilumnus Ng and Tan, 1984.

Spermiogenesis and spermatozoa in the relict bivalve genus Neotrigonia: relevance to trigonioid relationships, particularly Unionoidea

Spermiogenesis and spermatozoa in the relict trigonioid genus Neotrigonia are examined ultrastructurally. Mature Neotrigonia spp. spermatozoa exhibit the following features: (1) a blunt-conical nucleus; (2) an acrosomal complex composed of discoidal vesicles (9 to 15) arranged as a thin layer over the nuclear apex; (3) five (rarely four) spherical mitochondria positioned in depressions at the base of the nucleus; (4) proximal and distal centrioles (surrounded by the mitochondria); (5) a satellite complex anchoring the distal centriole and flagellum to the plasma membrane; and (6) a single flagellum. Spermatozoa of unionoids examined to date (Unionidae and Hyriidae only) exhibit similar features, including a nucleus with a blunt apex capped by a thin acrosomal complex (showing up to three vesicles). Among the Bivalvia, only Neotrigonia spp. and unionoid sperm possess an acrosomal complex composed of multiple vesicles. These data suggest that the Trigonioidea and Unionoidea are phylogenetically linked, but further work particularly on primitive unionoids is required to determine if this relationship is one of common ancestry or whether the Unionoidea have in fact been derived from the Trigonioidea.