Paroral Membrane Research Articles

Dexiotrichides pangi n. sp. (protozoa, ciliophora, scuticociliatia), a new marine ciliate from the north China sea.

The morphology, infraciliature, and silverline system of a new marine scuticociliate, Dexiotrichides pangi n. sp. were investigated. The new species is characterized by: size about 45-65 x 20-25 microm in vivo with kidney-like body shape and obliquely truncated semicircle-shaped apical plate; cytostome at bottom of conspicuously depressed oral cavity, which is located at the cell equatorial level; paroral membrane extending anteriorly to membranelle 3; scutica multi-rowed; 33-38 somatic kineties; contractile vacuole near ventral side and subcaudally positioned, opening at posterior end of somatic kinety 3; one oval macronucleus and one small micronucleus; caudal cilium positioned in a small pouch; marine habitat. Based on the data obtained, an improved diagnosis for the genus Dexiotrichides is suggested: body with circular cross-section and conspicuous cilia-free apical plate; buccal cavity conspicuously depressed with cytostome located near or at equatorial level; three membranelles transversely orientated each with 2-3 rows; paroral membrane zigzaging structure, extending to about half of the length of buccal field; multi-rowed scutica; somatic kinety one strongly shortened and terminating anteriorly at posterior end of buccal field; basal bodies in equatorial region arranged usually in circular pattern, while in the anterior portion of somatic kinety 2, basal bodies characteristically in pairs and separated from the posterior part of kinety 2; one caudal cilium.

Conjugation in the marine aloricate oligotrich Pelagostrobilidium (Ciliophora: Oligotrichia)

Morphogenesis and nuclear events during conjugation have been investigated for the aloricate oligotrich Pelagostrobilidium sp. using cytological staining methods. While several similarities between Pelagostrobilidium and sister groups (hypotrichs and stichotrichs) reported previously were recognized in the preconjugation behaviour, conjugation type and general nuclear division patterns, significant differences were found between them in the behaviour of oral and somatic ciliatures. In Pelagostrobilidium there was no reorganization in the somatic kineties during conjugation, in addition, it showed a very simple pattern of reorganization in the oral ciliature, which was very similar to stomatogenesis in asexual reproduction. A replacement oral apparatus was completed during the conjugation process and it very quickly replaced the old adoral zone when the conjugants separated. A noteworthy fact is that most of the parental adoral membranelles of Pelagostrobilidium persisted and were active during the entire conjugation period in spite of the loss of functional feeding organelles such as the cytostome and paroral membrane. The need to retain locomotion throughout the entire life cycle might be one of the adaptive features of oligotrichs required to occupy a certain niche in oceanic waters. The relatively short duration of the conjugation process (5.6 h) of Pelagostrobilidium is also likely to be important for life in oceanic waters.

Reconsideration of the morphogenesis in the marine hypotrichous ciliate, Aspidisca leptaspis Fresenius, 1865 (Protozoa, Ciliophora)

Morphogenetic events during division of the marine hypotrichous ciliate, Aspidisca leptaspis were investigated. The oral primordium of the opisthe develops hypoapokinetally in a sub-surface pouch posterior to the rear parental adoral zone, as in congeners. The parental adoral zones of membranelles are inherited by the proter. The proter's buccal cirrus develops from an “extra” anlage, which is formed de novo on the cell surface at an early stage of morphogenesis. Basal bodies in the oral primordium seem not to contribute to the formation of the buccal cirrus of the opisthe, which originates independently within the pouch opposite to the oral primordium and then migrates onto the cell surface. The paroral membrane derives from the posterior end of the oral primordium. Five frontoventral-transverse cirral anlagen are also formed de novo, initially as primary primordia, and develop into 3:3:2:2:2 cirri, respectively, in both dividers. Each of the four dorsal kineties evolves from an intrakinetal anlage in both proter and opisthe. Replication bands progress from the centre to the two ends of the macronucleus during the first half of the morphogenetic process, before this nucleus shortens and divides. The present investigation has clarified division processes within this species and confirmed some morphogenetic differences within the genus.

Morphogenetic processes in division of Uronemella filificum (Ciliophora, scuticociliatida)

The morphogenetic processes of Uronemella filificum (Kahl, 1931) Song and Wilbertι, were studied using protargol method. The stomatogenesis of U. filificum can be summarized as follows: membranelles 1–2, paroral membrane and scutica of the opisthe originate from the parental paroral membrane, while membranelle 3 in the opisthe develops from the parental scutica. The paroral membrane of the proter developes from the parental paroral membrane. The stomatogenetic sequences are similar to the previous descriptions for other related taxa. The phylogenetic position of Uronematidae is discussed in the light of morphogenetic data obtained.

Maristentor dinoferus n. gen., n. sp., a giant heterotrich ciliate (Spirotrichea: Heterotrichida) with zooxanthellae, from coral reefs on Guam, Mariana Islands

Maristentordinoferus n. gen, n. sp., was discovered on coral reefs on Guam in 1996 and has since been found frequently, at depths of 3–20 m. It forms black clusters, visible to the naked eye, especially on Padina spp. (Phaeophyta) and other light-colored backgrounds. When fully extended, this sessile ciliate is trumpet-shaped, up to 1 mm tall and 300 µm wide across the cap. The ciliate is host to 500–800 symbiotic algae. The anterior cap, or peristomial area, is divided into two conspicuous lobes by a deep ventral indentation. There is a single globular macronucleus, many micronuclei and, on average, 101 somatic ciliary rows and 397 adoral membranelles. M. dinoferus may be closely related to limnetic Stentor spp., but differs in two conspicuous features: (1) the cilia on the peristomial bottom are scattered (ordered rows in Stentor spp.) and (2) the paroral membrane is very short and opposite the buccal portion of the adoral zone of membranelles (in Stentor spp., it accompanies the entire membranellar zone). The cells appear dark due to stripes of cortical granules; the granules are more concentrated in a "black band" below the cap. The cortical pigment(s) is red fluorescent with a broad absorption peak in the blue (ca. 420–480 nm), and sharp peaks in the yellow-green (ca. 550 nm) and red (600 nm). Ultrastructural and molecular data demonstrate that the symbiont is a dinoflagellate of the genus Symbiodinium, the first unequivocal report of zooxanthellae in a ciliate. Phylogenetic analysis of a portion of the large subunit ribosomal RNA gene (28S rDNA) showed that the symbionts belong to Symbiodinium sp. clade C, a lineage that also inhabits many corals on Guam. The ciliate changes shape at night, and the symbionts, which are spread out in the cap during the day, are mostly withdrawn into the stalk at night; these changes were apparently not simply a response to darkness.

Characterization and identification of the Diophrys species (Protozoa, Ciliophora, Hypotrichida) based on RAPD fingerprinting and ARDRA riboprinting

Eight strains belonging to the three common Diophrys species were characterised using random amplified polymorphic DNA (RAPD) and amplified ribosomal DNA restriction analysis (ARDRA) methods with different random primers and restriction enzymes. The RAPD fingerprint patterns with three primers failed to reveal the intra- and inter-species relationships of members of Diophrys populations due to the low similarity indices (less than 46%) between different strains of the same species, which is out of the normal range of intra-species variation. However, ARDRA riboprinting successfully separated and identified D. oligothrix and D. appendiculata at the genetical level based on the patterns with Hinf I and Msp I enzymes. The patterns obtained with HinfI were species-specific for all three species, but Msp I did not distinguish D. scutum from D. appendiculata. According to our molecular data, Diophrys populations present relatively high biological diversity, even between different strains of the same species. D. oligothrix and D. appendiculata are two morpho- and geno-species, which confirms that some morphological features, such as patterns of basal bodies in dorsal kineties and paroral membrane, are reliable for species identification and separation.

Reinvestigations of Three “Well-known” Marine Scuticociliates: Uronemella filificum (Kahl, 1931) nov. gen., nov. comb., Pseud cohnilembus hargisi Evans & Thompson, 1964 and Cyclidium citrullus Cohn 1865, with Description of the New Genus Uronemella (Protozoa, Ciliophora, Scuticociliatida)

The living morphology, infraciliature and silverline system of 3 “well-known” marine scuticociliates, Uronemella filificum (Kahl, 1931) nov. gen., nov. comb. (formerly Uronema filificum Kahl, 1931), Pseudocohnilembus hargisi Evans & Thompson, 1964 and Cyclidium citrullus Cohn 1865 are reinvestigated and redescribed. Based on the data obtained, we suggest an establishment of a new genus Uronemella. The diagnosis for the new taxon: thigmotactic Uronematidae with generally pear-shaped body and subequatorially positioned cytostome; apical plate dominant; oral apparatus Uronema-like, one-rowed membranelle 1 about as long as membranelle 2; paroral membrane extending anteriorly to about mid-level of membrane 2; one caudal cilium; in vivo exhibiting typical rotatory movement with help of a caudal-cilium-associated sticky thread; generally in marine habitats. According to this definition, three nominal species as new combinations are transferred into this genus: Uronemella binucleata (Song, 1993) nov. comb. (= Homalogastra binucleata Song, 1993), Uronemella filificum (Kahl, 1931) nov. comb. (= Uronema filificum Kahl, 1931) and Uronemella cymruensis (Pérez-Uz & Hope, 1997) nov. comb. (= Urocyclon cymruensis Pérez-Uz & Hope, 1997). For comparison with Uronemella, some other closely-related taxa are also briefly outlined in the present paper.

Comparison of some closely-related Metanophrys-taxa with description of a new species Metanophrys similis nov. spec. (Ciliophora, Scuticociliatida)

The living morphology, infraciliature and silverline system of a marine scuticociliate Metanophrys similis nov. spec. have been observed and investigated. Based on both morphological and molecular biological data (using the random amplified polymorphic DNA fingerprinting method), several closely-related and easily confused taxa were compared. The diagnosis for this new taxon: slender marine Metanophrys with rounded cell ends and pre-equatorially positioned cytostome; in vivo 25–50 × 10–15 μm; 3-rowed membranelle 1 about as long as membranelle 2; paroral membrane extending anteriorly to about mid-level of membranelle 2; 11–12 somatic kineties; scutica with ca. 5–7 basal bodies arranged in a long line; extrusomes bar-like, aligned between somatic kineties; one caudal cilium and one macronucleus.

Stomatogenesis of the marine ciliate Paranophrys magna (Protozoa: Ciliophora: Scuticociliatida) from Qingdao, China

The morphology and stomatogenesis of the marine scuticociliate Paranophrys magna, collected from a crab-culturing pond in Qingdao, China, were studied. It possessed typical characteristics of the genus Paranophrys. The stomatogenesis of this species corresponds basically with the results provided in previous studies for this genus, the main sequence develops can be generalized as follows according to the Qingdao population: (i) in the proter: the remnant of the parental paroral membrane generates the new paroral membrane and the scutica; and (ii) in the opisthe: both the paroral membrane and scutica originate from the proliferation of the anterior part of the secondary primordial field, membranelles 1&2 derive from the posterior part of the secondary primordial field, while membranelle 3 from the proliferation of the parental scutica which form the primary primordial field. Some differences between our results and previous descriptions are compared and discussed.

Morphology and infraciliature of a marine scuticociliate with a polymorphic life cycle: Urocryptum tortum n. gen., n. comb.

A new genus and species combination are proposed for Urocryptum tortum n. gen., n. comb., a scuticociliate with a polymorphic life cycle. This marine ciliate was isolated from a sample taken at Gokasho Bay in Mie Prefecture (Japan). Specimens from different phases of the growth cycle were examined in vivo and with two silver staining techniques. Three life-history stages were observed: an exponential growth phase stage (trophont), a stationary phase stage (tomite), and finally a resting stage (cyst). The exponential growth form is laterally flattened and ovoid; it has 20-24 somatic kineties (SK) and a typical complement of scuticociliate oral structures. Polykinetid 1 (Pk1) has two longitudinal files of 6 kinetosomes (Ks); sometimes one or two additional kinetosomes are located anteriorly. Polykinetid 2 (Pk2) has two files of 6 or 7 Ks; a third file of three widely spaced kinetosomes is located on its right side, as well as a small curved row of 5 Ks positioned on the right hand side of the posterior end of Pk2. Polykinetid 3 (Pk3) has 3 rows of 4, 5, and 7 Ks's perpendicular to the haplokinety (Hk) or paroral membrane. The stationary growth phase cell is spindle-shaped and has a similar number of SK that are much more closely spaced than in exponentially growing specimens. Oral infraciliary structures are reduced in size, having fewer kinetosomes and being positioned more anteriorly in the cell. Pk1 is composed of two files of 5-Ks, Pk2 has only two files of 6-7 Ks, and Pk3 has two to three rows of 3-4 Ks. The Hk is displaced anteriorly and becomes straight, losing the shape typical of exponential growth phase cells. Cysts are pyriform with a wide cyst wall; no infraciliary structures were visible.

Ciliates from Antarctic sea ice

Five ciliates, Chlamydonella prostomata nov. sp., Paractedoctema acruosa nov. gen., nov. sp., Urocyclon ovatum nov. gen., nov. sp., Porpostoma grassei (Corliss and Snyder 1986) and Cytharoides balechi Tuffrau 1974, collected from sea ice in the Weddell Sea, Antarctica were morphologically and taxonomically investigated. The new genus Paractedoctema is characterized as: Cyclidiidae with naked snout-like apical end and three well-developed membranelles which are multi-rowed in structure and closely apposed one to another; paroral membrane extending anteriorly to about mid-level of M1; one caudal cilium; and silverline system Cyclidium-like. Since Urocyclon Small and Lynn 1985 is a nomen nudum because no type species has been fixed, we re-establish the genus and give a revised definition: uronematids mostly with inverted pear-shaped body and subequatorially positioned cytostome; apical plate dominant; membranelle 1 highly reduced; and paroral membrane extending anteriorly to about mid-level of membrane 2. Based on this new definition, a new combination is suggested: Homalogastra cymruensis (Perez-Uz and Hope 1997) comb. nov. (formerly Urocyclon cymruensis Perez-Uz and Hope 1997). For the well-known genus Chlamydonella, an improved diagnosis has been given according to our observations and the data obtained: Lynchellidae without plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or slightly fragmented with leftmost rows parallel to each other, which are arched transversely; and cytopharyngeal rods (nematodesmata) toothed. Macronucleus usually dimorphic. Regarding the related genus Lynchella Kahl 1933, we suggest that the original diagnosis by Kahl should be maintained. Thus, the genus diagnosis is re-provided: Lynchellidae with plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or fragmented with some rows parallel to each other; cytopharyngeal rods toothed; macronucleus generally dimorphic. In the light of the redefinition, a new combination has been made: Chlamydonella nordica (Jankowski 1968) comb. nov. (formerly Lynchella nordica Jankowski 1968).

Morphology and Morphogenesis of Metopus hasei Sondheim, 1929 and M. inversus (Jankowski, 1964) nov. comb. (Ciliophora, Metopida)

ABSTRACT The morphology and morphogenesis of Metopus hasei Sondheim, 1929 and M. inversus (Jankowski, 1964) n. comb, were investigated using live observation, silver impregnation, and scanning electron microscopy. Metopus has a spiral body organization and the ventral margin of the preoral dome bears five specialized ciliary rows, that form the so‐called perizonal stripe. Division is homothetogenic, occurs in freely motile (i. e. non‐encysted) condition, and includes a partial reorganization of the parental oral apparatus. During division, the complicated cell shape becomes ellipsoidal and all ciliary rows arrange meridionally. Stomatogenesis is entirely somatic (≅ pleurotelokinetal) and commences with the formation of kinetofragments in some dorsolateral kineties. The fragments become the opisthe's adoral membranelles, while the paroral membrane is generated by the left two perizonal ciliary rows, which proliferate kinetids intrakinetally. The perizonal stripe of the opisthe is generated by the three right parental perizonal kineties, which divide, and by two dorsolateral ciliary rows, which are added. The morphogenetic processes, especially the unique mode of formation of the paroral membrane, are used to define the order Metopida Jankowski, 1980 n. stat. more properly. The ontogenetic, ultrastructural, and sequence data available give no clear indication about metopid phylogeny, but definitely exclude metopids from the classical heterotrichs, with which they were classified for more than 100 years. Accordingly, we place the Metopida as incertae sedis in the subphylum Intramac‐ronucleata Lynn, 1996.

Morphology and infraciliature of some soil ciliates (Protozoa, Ciliophora) from continental Antarctica, with notes on the morphogenesis of Sterkiella histriomuscorum

AbstractThe morphology of seven soil ciliate species from continental Antarctica was investigated using live observation and protargol impregnation. Observations on two populations of Protospathidium serpens corroborate the view that this species usually has a single, more-or-less nodular, macronucleus distinguishing it from P. muscicola, which possesses 10–30 nodules. The Antarctic specimens of Protospathidium terricola differ inconspicuously from the type population in that they are slightly larger, have fewer ciliary rows (17 vs 21), and the fragments of the circumoral kinety are less distinctly separated from each other. Spathidium seppelti nov. spec, resembles 5. bavariense, but has 100–200 macronuclear nodules and a conical depression in the dorsal third of the oral bulge. Odontochlamys wisconsinensis nov. comb, (basionym: Chilodonella wisconsinensis Kahl, 1931) has four right field kineties and an oral basket consisting of 14 rods; the dorsal brush is near the anterior margin and usually consists of four cilia. The Antarctic population of Pseudochilodonopsis mutabilis possesses a regular dorsal hump and only 12–14 (about 15 in Austrian type population) phary ngeal rods. Oxytricha opisthomuscorum has six dorsal kineties with long cilia and a buccal cirrus near the anterior end of the paroral membrane. The Antarctic specimens of Sterkiella histriomuscorum have fïve transverse cirri. Their morphogenesis differs slightly from that of a population having four transverse cirri in that the daughter's anlagen are more distinctly separated and some temporal sequences are different.

Urocyclon cymruensis n. sp. (Ciliophora: Uronematidae). A new scuticociliate associated with decaying seaweed from the Welsh Coast of UK

Summary A new ciliate was isolated from samples of decaying seaweed collected from the intertidal area of St. Mary's Well Bay (Sully, Wales). Its morphology was studied in vivo and in cells impregnated with silver carbonate and silver nitrate. This new species is 29 × 16 μm and is inverted pear-shaped with a broad anterior pole. It has small pyriform cysts. The number of kinetal rows is generally 26. The cytostome is situated sub-equatorially. Polykinetid Ml is long and non-ciliferous with five widely spaced kinetosomes in a row. Polykinetid M2 is a long single row of six kinetosomes ending on a transverse group of four kinetosomes disposed in two lines of two kinetosomes each. The paroral membrane (PM) is typically arranged in two clearly differentiated segments, A and B, both two rows of kinetosomes in a haplokinetal configuration. The contractile vacuole pore (CVP) is located at the end of the fourth somatic kinety.

Redescription of Zoothamnium niveum (Hemprich & Ehrenberg, 1831) Ehrenberg, 1838 (Oligohymenophora, Peritrichida), a ciliate with ectosymbiotic, chemoautotrophic bacteria

Summary A very large and fast growing species of Zoothamnium Bory de St. Vincent, 1826 (Oligohymenophora, Peritrichida), Z. niveum (Hemprich & Ehrenberg, 1831) Ehrenberg, 1838 has been discovered in mangrove channels of the Caribbean Sea, the Gulf of Mexico, and the Red Sea. This colonial, sessile ciliate is remarkable for its obligatory association with ectosymbiotic, chemoautotrophic, most likely sulfur-oxidizing bacteria covering almost the entire body of the host. Two distinct morphotypes of bacteria — rods and cocci — presumably representing only one species, are present. A redescription of Z. niveum is made based on live observations, silver carbonate stainings after Fernandez-Galiano [29], and scanning electron microscopy. Z. niveum is characterized by a feather-like colony, a stalk which is often divided, branches occurring alternately on the stalk, and an alternate arrangement of zooids on the branches. Three different types of zooids are present: microzooids and undividing terminal zooids with a slender, strongly asymmetric oral side; roundish to ellipsoid macrozooids; and ellipsoid dividing terminal zooids. All have a striped silverline system with pellicular pores and a macronucleus with a unique shape. The oral ciliature turns 1 1/4 in a clockwise direction when viewed from inside the cell. The ciliature of the microzooids consists of a paroral membrane, three adorai membranelles (polykineties), one stomatogenic kinety orally, and one circular irregular row of barren kinetosomes aborally (trochal band). The ciliature of the macrozooids is the same as in the microzooids, except for an additional long epistomial membrane orally and a telotrochal band of several circular rows of kinetosomes aborally. A comparison of morphological characters within the genus Zoothamnium is provided, with special attention given to different forms of epigrowth on various representatives of this genus.

Morphogenetic study during cell division in Euplotidium itoi (ciliata, hypotrichida)

Summary The present study, performed by means of light and scanning electron microscopy, is the first report in which morphogenetic processes are analyzed in detail in a member of the Euplotidium genus. From our observation it arises that E. itoi shares many morphogenetical features with members of the Euplotidae family, particularly with Euplotes. The replication band forms at the distal end of each macronuclear piece, proceeds proximally and disappears as the fusion of the pieces occurs. The parental adorai zone of membranelles (AZM) and paroral membrane (PM) are inherited by the proter; the corresponding structures form de novo, probably from separated anlagen, in the opisthe. New sets of cirri are formed for both products of division. Only as far as the proliferation of dorsal kineties is concerned does E. itoi resemble the genus Diophrys rather than Euplotes.

Philasterides dicentrarchi, n. sp., (ciliophora, scuticociliatida), a histophagous opportunistic parasite of Dicentrarchus labrax (Linnaeus, 1758), a reared marine fish

In sea bass Dicentrarchus labrax (L.) reared in the Mediterranean sea, mortality suddenly arose. The diseased fishes, noticeable when almost dead, were massively infested with a histophagous ciliate. Depending on the infected host organs, the ciliate showed in its food vacuoles various categories of ingested cells: erythrocytes, ovocytes, and others. The infecting mode of this presumed “parasite” is still unknown, all experimental infections having failed. Morphological, biometric and ultrastructural studies lead to the conclusion that, because of its morphological characteristics and its main stomatogenesis processes, this ciliate is a Scuticociliatida Philasterina. Compared to other known species, it differs by its small size, the small and regular number of its somatic kineties, the position of its buccal organelles (and, mainly, the bipartite paroral membrane), the presence of two types of extrusomes, and a perinuclear envelope. All these characteristics justify the creation of a new species: Philasterides dicentrarchi. This particular ciliate habitat is compared to that of other commensal or opportunistic parasitic ciliates of invertebrates and marine fishes.

Morphology and morphogenesis of Thigmokeronopsis antarctica nov. spec, and T. crystallis nov. spec. (Ciliophora, hypotrichida) from Antarctic Sea Ice

Summary The morphology and morphogenesis of Thigmokeronopsis antarctica nov. spec, and T. crystallis nov. spec, discovered in brine channels of Antarctic sea ice, were investigated using protargol silver impregnation. Both species are characterized by a left postoral ciliary field which is composed of much fewer longitudinal files than in T. jahodai, the type species of the genus. In addition, the new species have unique morphogenetic features, viz. all marginal and dorsal primordia originate de novo and the macronuclear nodules fuse incompletely during cell division. Thigmokeronopsis antarctica is distinguished from T. jahodai by shortened midventral rows, 1 left postoral file and 3–4 buccal cirri; transverse cirri are perhaps absent. Thigmokeronopsis crystallis has long midventral rows, usually 5 slightly irregular left postoral files, 1 buccal, and 8 transverse cirri. Morphogenesis is similar in both species, i.e. an anarchic field originates close to left midventral cirri and produces the opisthe's adorai membranelles, undulating membranes, and fronto-ventral-transverse (FVT) cirri; the proter's anarchic field forms near the paroral membrane and splits into primordia for undulating membranes and adorai membranelles; the FVT anlage originates independently close to the anterior left midventral cirri; all primordia form apparently de novo and all parental cirri are replaced. Reorganization resembles the development of the proter.

Morphogenesis of the marine ciliate Diophrys oligothrix Borror, 1965 during the cell division (protozoa, ciliophora, hypotrichida)

Summary Morphogenetic events during division of the marine hypotrichous ciliate Diophrys oligothrix were investigated by light microscopy on protargol impregnated specimens. The morphogenesis of both the ventral and dorsal infraciliature proceeds in a very similar way to that in D. scutum . The opisthe oral primordium (OP), which develops in a subsurface pouch, forms de novo anterior to the parental transverse cirri. Basal bodies formed in the OP field do not contribute to any other cirral anlagen. Only the rear part of the parental adorai zone of membranelles (AZM) is reorganized during the later morphogenetic process and then was inherited by the proter. Both the endoral and paroral membrane (UM) develop from an “extra” anlage which seems to derive from the posterior end of the reorganized AZM in the proter and from the oral primordium in the opisthe. All cirral anlagen form de novo and do not develop in association with any parental structures. Each of the 4 dorsal kineties evolves from a separate dorsal kinety anlage in both proter and opisthe. The replication band at the distal end of each macronucleus proceeds proximally and disappears as the two nuclear segments fuse. This investigation documents several ontogenetic differences among the species of the genus Diophrys . The morphogenetic process in our population differs from that in D. scutum in the position of the oral primordium which is distinctly anterior to the transverse cirri and between the marginal cirri, the reorganization of the parental AZM is limited merely to the last 1/3 of its length and is relatively inconspicuous. In contrast to the previous report, the origin of the UM and paroral cirrus in both proter and opisthe is apparently connected with the oral primordium (in opisthe) or reorganizing part of parental AZM and UM (in proter).

Corticocolpoda kaneshiroae N. G., N. Sp., a New Colpodid Ciliate (Protozoa, Ciliophora) from the Bark of Ohia Trees in Hawaii

ABSTRACT Corticocolpoda kaneshiroae n. g., n. sp. was discovered in the bark of Ohia trees (Metrosideros polymorpha) from the Hawaiian Archipelago. Its morphology and infraciliature were studied in live cells, with the scanning electron microscope, as well as in specimens impregnated with protargol, silver nitrate, and silver carbonate. The new genus, Corticocolpoda, belongs to the family Colpodidae and is unique in having a left oral ciliary field (polykinetid) composed of 13–20 equidistantly spaced, paired rows of monokinetids. The new species, C. kaneshiroae, measures 100–300 × 60–250 μm and has a huge vestibulum used to capture large food items, mainly other ciliates. The oral ciliary fields are within the vestibulum and of equal length; the right field is a paroral membrane composed of a single row of dikinetids. Several micronuclei are attached to the ellipsoid macronucleus. The mucocysts are inconspicuous and arranged around the somatic dikinetids. The resting cyst is globular and has a 1–2 μm thin, firm, yellowish inner wall and a 20‐μm‐thick, fragile, hyaline outer wall. Convergent evolutionary paths and a possible polyphyly of the Colpodidae are discussed. An improved key to the genera of the family Colpodidae is provided. Twenty‐three species of ciliates and one flagel***iate (Hemimastix amphikineta), which occurred together with C. kaneshiroae, are new for the fauna of Hawaii and listed in the ecology section.