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The genera Coriplites Foissner, 1988 and Apocoriplites nov. gen., which differ by the number of dorsal brush rows (3 vs. 2), belong to the haptorid Litostomatea and have a distinct feature in common: they lack oral extrusomes. Based on three new species, the diagnosis of the genus Coriplites is amended to include the wide spacing of the brush dikinetids and the heavily refractive cortical granules. Using standard methods, we redescribe C. terricola Foissner, 1988 and describe three new species: C. grandis (from swamp soil of Australia), C. proctori (from tanks of bromeliads in Jamaica), and Apocoriplites lajacola (from granitic rook-pools in Venezuela). Species are distinguished by the nuclear apparatus (a single nodule vs. two nodules with a micronucleus in between), the body size (<100 μm vs. >100 μm), the number of ciliary rows, and details of the dorsal brush (isostichad vs. heterostichad). In over 1,000 soil samples, only C. terricola has been found in all main biogeographic regions, while the other species have been found only at their type locality, i.e., in the southern hemisphere, where the genus possibly originated.
Coriplites belongs to a group of haptorids, which has, at first glance, a quite simple organization: the body is a completely ciliated sac, of which the narrower anterior end bears the mouth opening. Complex oral structures are absent, except of a dikinetidal circumoral kinety at the base of an inconspicuous oral bulge. Thus, such ciliates are difficult to identify in vivo (Kahl 1930). It was only during the past 20 years that silver impregnation and transmission electron microscopy provided new features for a more reliable identification and classification, especially details of the oral basket and the dorsal brush, a field of paired cilia with unknown function (Foissner and Foissner 1988, Foissner and Xu 2007, Foissner et al. 2002, Puytorac 1994).
Coriplites belongs to the Acropisthiina Foissner and Foissner (1988), a fairly large group of haptorids, in which the oral basket is not only composed of rods originating from the circumoral kinety but also from oralized somatic monokinetids in the anterior region of the somatic ciliary rows. Originally, the Acropisthiina contained a single family (Acropisthiidae) with four genera: Acropisthium, Fuscheria, Papillorhabdos and Actinorhabdos. Several new genera were added by Foissner (1988, 1996, 1998a, 1999) and Foissner et al. (1999, 2002), viz., Pleuroplites, Pleuroplitoides, Balantidion, Coriplites, Chaenea, Diplites, Dioplitophrya, Sikorops, and Clavoplites. Here, a fourteenth fuscheriid genus is added: Apocoriplites. These genera were classified in three families (Foissner and Foissner 1988, Foissner 1996, Foissner et al. 2002): the Pleuroplitidae (with subapical, extracystostomal extrusome bundle and enchelyodonid general organization with meridional kineties), the Fuscheriidae (general organization enchelyodonid with meridional kineties), and the Acropisthiidae (general organization spathidiid with kineties more or less curved anteriorly).
The genus Coriplites was established with a single species by Foissner (1988). It is unique in having lost the oral extrusomes, a main feature of the haptorids (Corliss 1979). During the past 20 years, we have investigated over 1,000 soil samples collected globally. In these samples, we discovered not only most of the genera cited above, but also three new coriplitids which will be described in this paper. This great increase in genera and species shows a huge portion of undescribed ciliate diversity (for a review, see Foissner et al. 2008).
The origin of the material is provided in the individual species descriptions. Basically, all samples are from terrestrial or semiterrestrial habitats. With the exception of the sample containing Coriplites proctori, all materials were air-dried for at least one month and then stored in plastic bags. Later, samples were investigated with the non-flooded Petri dish method, as described by Foissner et al. (2002). Briefly, this simple method involves placing 50–500 g soil in a Petri dish (13-–18 cm wide, 2–3 cm high) and saturating, but not flooding it, with distilled water. These cultures were analysed for ciliates by inspecting about 2 ml of the run-off on days 2, 7, 14, 21, and 28. Except of C. proctori, the descriptions of the new species were based on material obtained from such cultures, i.e., no pure cultures were established. Coriplites proctori was discovered in the tanks of a Jamaican bromeliad. The species became rather abundant in a mixed culture of tank water with the original organism community and some squashed wheat grains.
Morphological and presentation methods followed Foissner (1991) and Foissner et al. (2002). However, C. proctori was fixed in 50% ethanol (final concentration) – the specimens shrank considerably and did not impregnate well with protargol. Terminology follows Corliss (1979) and the refinements introduced by Foissner and Xu (2007).
The coriplitids (= Coriplites and the new genus Apocoriplites described below) belong to the haptorids, according to their general organization (Foissner 1988; Foissner et al. 2002). However, they fall into a distinct subgroup lacking oral extrusomes (toxicysts), a main feature of the haptorids (Corliss 1979). Further, they have oralized somatic monokinetids, that is, oral basket rods originate not only from the dikinetidal circumoral kinety but also from the anterior kinetids of the somatic ciliary rows (Foissner 1988). This type of haptorids has been classified in a distinct suborder, the Acropisthiina, by Foissner and Foissner (1988). The body organization of the coriplitids is enchelyodonid, and thus they belong to the family Fuscheriidae, as defined by Foissner et al. (2002).
Genera within the Fuscheriidae are distinguished by the number of dorsal brush rows (two in Fuscheria Berger et al. 1983, Actinorhabdos Foissner 1984, Diplites Foissner 1998a, and Apocoriplites nov. gen.; three in Coriplites Foissner 1988, Balantidion, as redescribed by Foissner et al. 1999, and Dioplitophrya Foissner et al. 2002) and the shape and types of extrusomes (lacking in Coriplites and Apocoriplites; oblong in Balantidion; pin-shaped in Fuscheria, graver-shaped in Actinorhabdos; pin-shaped and clavate in Dioplitophrya; rod-shaped somatic and narrowly ovate or ellipsoidal oral toxicysts in Diplites).
Coriplites was established with a single species: C. terricola Foissner, 1988. Thus, the diagnosis focused on the most conspicuous feature, i.e., the absence of oral toxicysts. Here, we describe two further species and a new, closely related genus, Apocoriplites, all having two further specific features in common: widely spaced brush dikinetids (Figs (Figs1e,1e, ,2e,2e, ,3e,3e, ,4h,4h, ,5b,5b, ,6a)6a) and conspicuous cortical granules (Figs 3a, b), likely mucocysts, which can be extruded, forming a thick, yellowish-impregnated cover in protargol preparations (Figs (Figs1h,1h, ,5e).5e). Both features are rare in haptorids and thus useful for the definition of the genus.
Coriplitids lack oral extrusomes, that is, a main diagnostic feature of the haptorids (Corliss 1979, Foissner and Foissner 1988). We consider it unlikely that they are too small to be recognizable in the light microscope, especially because they are also absent from the large C. grandis (~180 × 35 μm). Usually, haptorids of this size have toxicysts longer than 5 μm. In all likelihood, the coriplitids lost their extrusomes, which is observed in a variety of haptorid genera, for instance, in Arcuospathidium cooperi and Edaphospathula inermis, both described in Foissner and Xu (2007).
The occurrence of extrusome-less species in various haptorid genera provokes the question whether Coriplites and Apocoriplites are “good” genera at all. Could they belong to another acropisthiid genus? We cannot exclude this possibility at the present state of knowledge, but it is unlikely that they belong to one of the described acropisthiid genera (Foissner et al. 2002). There are three features that support our assumption, viz., the specific nuclear pattern present in most coriplitids (two globular macronucleus nodules with a micronucleus in between), the widely spaced dorsal brush dikinetids, and the highly refractive cortical granules. Although individual features are found in other haptorids (Blatterer and Foissner 1988, Foissner et al. 2002, Foissner and Xu 2007), they never occur together, as in the coriplitids.
Coriplitid ciliates prefer semiterrestrial habitats, such as mossy puddles, swamp soil, and bromelian cisterns. Records from lakes or running waters are not known, while C. terricola occurs in true terrestrial habitats, i.e., in soil from deciduous and coniferous forests (Foissner 1988, Blatterer and Foissner 1988).
All coriplitids are rare, at least under the isolation method used (non-flooded Petri dish culture). Thus, their geographic distribution is difficult to estimate. In over 1,000 soil samples (Foissner 1998b; Foissner et al. 2002, 2005), only C. terricola occurred in all main biogeographic regions, while the three other species have been found only at their type locality. Except for the cosmopolitan C. terricola, all species have been found only in Gondwanan areas, suggesting an origin of the genus in the southern hemisphere.
Detailed autecological data from coriplitids are not known. They occur in a wide variety of habitats (see below) with a pH range from about 3.5 to 7. In the non-flooded Petri dish cultures, their abundance is low to moderate.
All species can be identified on careful live observation, though identification of C. terricola and Apocoriplites lajacola should be confirmed in protargol preparations.
Fuscheriidae Foissner and Foissner (1988) without oral extrusomes and with widely spaced brush dikinetids. Cortex gelatinous, 1–2 μm thick due to highly refractive granules, likely mucocysts. Nuclear apparatus usually consisting of two globular macronucleus nodules and a micronucleus in between.
Coriplites terricola Foissner, 1988.
The generic name is a composite of the Greek words “coris” (without) and “hoplites” (soldier), meaning a ciliate without extrusomes. Masculine gender.
1988 Coriplites terricolaFoissner, Stapfia 17:93 (1 holotype and 1 paratype slide with protargol-impregnated specimens from type locality have been deposited in the Museum of Natural History, London. The holotype is contained in that slide which contains the type of Birojimia terricola Berger and Foissner, 1989).
Size about 60 × 13 μm in vivo; elongate bursiform to narrowly ellipsoidal. Two globular macronucleus nodules with a globular micronucleus in between. On average 12 ciliary rows, three anteriorly differentiated to a heterostichad dorsal brush occupying about 34% of body length.
Upper soil layer of a deciduous forest in the surroundings of Birojima, Amakusa, Kumamoto Prefecture, Japan, E129° N32°30′.
Not given in original description. Obviously, the Latin terricola (living in soil) refers to the habitat the species was discovered.
Five populations from Japan, Australia, and South America have been studied in vivo and protargol preparations. However, detailed data from silvered specimens are available only from the Japanese and one of the two Australian populations (Table 1). All populations match well, suggesting conspecificity. Thus, the data are combined in the diagnosis and description.
Size little variable within and between populations, i.e., 50–80 × 10–15 μm in vivo (n = 9), usually near 60 × 13 μm; length:width ratio on average 4–5:1 both in vivo and protargol preparations. Shape elongate bursiform, rarely ellipsoidal or almost cylindroidal; unflattened; brush side moderately convex, ventral side flat, slightly concave or slightly convex, specimens thus somewhat asymmetrical (Figs 1a, c–f); slightly contractile under mild coverslip pressure, specimens from the Easter Islands shorten by up to 20% when removed from sample or slide with a fine pipette. Nuclear apparatus on average slightly posterior of mid-body, highly characteristic, i.e., composed of two globular macronucleus nodules and a single micronucleus in between (Figs 1a, e). Macronucleus nodules spherical to broadly ellipsoidal, contain a circular or reticular nucleolus, 7–8 μm across in vivo. Micronucleus globular, about 1.5 μm across in vivo. Postconjugants with 1–4 small, globular macronucleus nodules (Figs 1c, d). Cortex colourless, very flexible, smooth to rather distinctly furrowed by ciliary rows, conspicuous due to the highly refractive granules contained in an about 1 μm thick, gelatinous layer; individual granules about 0.8 × 0.4 μm in size, arranged in circa eight narrowly spaced rows between two kineties each (Fig. 1b), become extruded during fixation, forming a thick, yellowish-impregnated envelope (Fig. 1h). Cytoplasm colourless, rather hyaline, especially in anterior quarter containing some faint, 1–3 μm long structures, likely mitochondria; main body portion more or less opaque due to lipid droplets 1–4 μm across and up to 10 μm-sized food vacuoles with heterotrophic flagellates and small ciliates, such as Drepanomonas pauciciliata, Protocyclidium muscicola, and Cyrtolophosis mucicola (Fig. 1a). Swims rather rapidly to rapidly rotating about main body axis.
Cilia about 8 μm long in vivo, ordinarily spaced except subapically where some more narrowly and regularly spaced kinetids form a circular pattern; arranged in an average of 12 longitudinal, equidistant, ordinarily spaced rows (Figs 1e, f, h). Dorsal brush occupies an average of 34% of body length, heterostichad because row 1 shorter than row 2 by about 40%; rows 2 and 3 of similar length, row 3 with a monokinetidal tail extending to mid-body with 1 μm long bristles; anterior tails composed of 1–2 monokinetids; row 1 composed of an average of 6 dikinetids, row 2 of 10, and row 3 of 11. Brush bristles inconspicuous because only 2–3 μm long, V-like spread, rodshaped to flame-like; anterior basal body of dikinetids of rows 1 and 2 possibly with an ordinary cilium in Japanese population (Foissner 1988), while both bristles are about 2.5 μm long in a Venezuelan specimen (Fig. 1g).
Oral bulge transverse truncate and more or less depressed in centre, inconspicuous because in vivo only about 5 μm across, 2–3 μm high, and indistinctly set off from body proper, except of Venezuelan specimens where it is slightly narrowed and thus more distinct. Circumoral kinety circular, composed of about 12 slightly oblique dikinetids (Figs 1e, f). Nematodesmata short and fine, do not form bundles, originate from circumoral dikinetids and 3–8 oralized somatic monokinetids at anterior end of ciliary rows (Fig. 1h).
Coriplites terricola has been found in all main biogeographic areas, except of Antarctica, suggesting cosmopolitan distribution (Foissner 1998b, Foissner et al. 2002): Austria (Foissner et al. 2005), Japan and Australia (Foissner 1988, Blatterer and Foissner 1988), Namibia (Foissner et al. 2002), and South America (Venezuela, Easter Islands; Foissner 1998b). Obviously, C. terricola occurs in a variety of soils suggesting a wide ecological range, but it never became abundant in the non-flooded Petri dish cultures. The prey is ingested whole because still recognizable in the food vacuoles.
Ciliates of this type are rather frequent and thus difficult to identify. Fortunately, C. terricola, the most common coriplitid, has two highly characteristic features easy to recognize: the lack of oral extrusomes and the special nuclear pattern, which is rare in other haptorids. Coriplites grandis, which has the same features, is much larger (180 × 35 μm vs. 60 × 13 μm).
Size about 180 × 35 μm in vivo; obclavate. Two ellipsoidal macronucleus nodules with a globular micronucleus in between. On average 26 ciliary rows, three anteriorly differentiated to an isostichad dorsal brush occupying about 40% of body length.
Upper soil layer (0–5 cm) of a swamp near Eubenangee, south of Cairns, Australia, 17°S 145°E.
One holotype slide and 5 paratype slides with protargol-impregnated specimens have been deposited in the Biology Centre of the Museum of Upper Austria, Linz (LI). Relevant specimens are marked by black ink circles on the coverslip.
The Latin adjective grandis (large) refers to the comparatively large size.
Three populations from Australia were studied in vivo, namely, from the east coast (Eubenangee) and from two localities near Alice Springs in the red centre of the continent. The populations match very well, therefore diagnosis and description summarize all observations except of some differing details. Protargol preparations are available only from the type locality.
Size 150–220 × 30–40 μm in vivo, usually about 180 × 35 μm; length:width ratio 3–6:1, on average 4:1 in protargol preparations, where specimens are slightly shrunken in length, but inflated in width (162 × 38 μm; Table 2). Shape more or less obclavate, rarely almost fusiform, distinctly narrowed and more or less curved in anterior third; body symmetric and flexible, unflattened to slightly flattened (Figs 2a, e–g, 3c, d). Specimens from Alice Springs pyriform under coverslip because narrowed anterior half contracted up to 40%. Nuclear apparatus up to 75 μm long in vivo, on average 40 μm in protargol preparations, in or underneath mid-body, conspicuous because composed of two ellipsoidal macronucleus nodules and a globular micronucleus in between; individual nodules up to 30 × 15 μm in vivo, while only about 20 × 11 μm in protargol preparations, likely due to some preparation shrinkage; nucleoli scattered, numerous, globular, oblong or forming irregular masses. Micronucleus surrounded by a distinct, membrane-like structure, about 5 μm across in vivo (Figs 2a, f, g; Table 2). Contractile vacuole in rear end. No oral extrusomes detectable by light microscopy in any of the populations. Cortex flexible, gelatinous, colourless, rather distinctly furrowed by ciliary rows, conspicuous because about 1.5 μm thick due to highly refractive granules (Figs 2b, c, 3a, b); individual granules about 1.3 × 0.8 μm in size, arranged in 7–10 narrowly spaced rows between each two kineties, can be extruded but do not swell, slightly less conspicuous in one of the two Alice Springs populations. Cytoplasm colourless, packed with many lipid droplets 0.5–5 μm across and 12–30 μm-sized food and fecal vacuoles containing organic debris and crystals 3-–5 μm in size. In oral area a pharyngeal mass composed of rather refractive globules about 1 μm across (Fig. 2a). Feeds on medium-sized ciliates, such as Gonostomum affine, ingested wholly because still identifiable in the food vacuoles. Moves serpentinely and rather slowly by rotation about main body axis.
Cilia about 10 μm long in vivo, ordinarily spaced, arranged in an average of 26 longitudinal, equidistant, ordinarily spaced rows more densely ciliated around oral entrance in some specimens (Figs 2e–g, 3d–f; Table 2). Dorsal brush isostichad, occupies an average of 40% of body length, bristles up to 3 μm long; brush row 1 slightly shorter than rows 2 and 3, composed of about 22 dikinetids, rows 2 and 3 each composed of an average of 27 dikinetids. Row 1 dikinetids associated with a longer anterior and a shorter posterior bristle, rows 2 and 3 composed of slightly inflated bristles of same length (Figs 2a, d, e, h, 3d, e); at least row 3 followed by a monokinetidal bristle tail.
Oral bulge broadly elliptical, inconspicuous because low and indistinctly set off from body proper, about 8 μm wide and 1–2 μm high in vivo, slightly depressed in centre. Nematodesmata about 20 μm long, originate from 12–16 oralized somatic monokinetids at anterior end of ciliary rows and from circumoral dikinetids at base of oral bulge (Figs (Figs2h,2h, 3f, g). Circumoral kinety composed of vertically orientated dikinetids.
To date found only at type locality and in two soil samples from Erldunda, a village in the surroundings of Alice Springs, Central Australia. Thus, Coriplites grandis is possibly restricted to this continent. The soil from type locality was grey and had pH 3.8, while it was red and circumneutral (pH 6.3) in one of the samples from Central Australia. Both samples contained much litter and many fine roots. Coriplites grandis from type locality reached significant abundance in the non-flooded Petri dish culture one month after rewetting, whereas the two populations from Alice Springs appeared already two weeks, respectively, three days after rewetting of the sample, suggesting different ecotypes.
Coriplites grandis can hardly be confused with other haptorids because few show such conspicuous body shape and nuclear pattern. Nearly all of them, including C. terricola, are much smaller (< 100 μm) and have less than half the number of ciliary rows. Species with the same nuclear pattern are, inter alia, Apocoriplites lajacola, Cultellothrix spp. (Foissner & Xu 2007), Epitholiolus chilensis and Apoenchelys bamforthi (Foissner et al. 2002); the latter is the only one reaching a similar length as Coriplites grandis.
Size about 65 × 25 μm in vivo; bursiform and slightly curved. Macronucleus oblong with single discoidal micronucleus attached laterally. On average 12 ciliary rows, three anteriorly differentiated to a heterostichad dorsal brush occupying about 20% of body length.
Tanks of Achmea paniculigera (Bromeliaceae) in western Jamaica, i.e., near the road between the villages of Aberdeen and Quick Step (parish St. Elizabeth), E77°42′ N18°13′. Achmea paniculigera is endemic to Jamaica (Adams 1972).
One holotype slide and 2 paratype slides with protargol-impregnated specimens have been deposited in the Biology Centre of the Museum of Upper Austria, Linz (LI). Relevant specimens are marked by black ink circles on the coverslip.
This species is named in honour of the famous botanist Dr. Georg R. Proctor (Jamaica Museum of Natural History, Kingston), who joined our field trips in February 2008 and identified the bromeliads to species level.
As the specimens shrank considerably, i.e., about 35% due to alcohol fixation and protargol preparation, we base data on average in vivo bodysize.
Size 50–80 × 20–30 μm in vivo, usually near 65 × 25 μm; length:width ratio on average 2–4:1, both in vivo and in protargol preparations (Table 2). Shape of ordinary specimens bursiform to almost ellipsoidal; unflattened; anterior half narrowed and brush side moderately convex, ventral side flat, slightly concave or slightly convex, specimens thus somewhat asymmetrical (Figs 4a, c, d–f, h, i, 6f, g). Theronts more slender (~6:1) and almost cylindroidal (Fig. (Fig.4c,4c, ,6f),6f), trophonts distinctly bursiform (2–3:1; Figs 4d, e, ,6g).6g). Macronucleus in, slightly anterior, rarely posterior of mid-body, frequently reniform or oblong and about 15 μm long in protargol preparations; nucleoli of various shapes, scattered. Micronucleus discoidal, 2–4 × 0.5 μm, attached to macronucleus laterally (Figs 4a, f, h, 6f, g; Table 2). Contractile vacuole in rear end. No oral extrusomes detectable in the light microscope. Cortex flexible, colourless, rather distinctly furrowed by ciliary rows, granulation as distinct as in congeners (Fig. 4a). Cytoplasm colourless, rather hyaline, especially in anterior third containing some faint structures, 2.5 × 1 μm, likely mitochondria; main body portion more or less opaque due to lipid droplets 1–3 μm across and some food vacuoles with remnants of small ciliates (Fig. 4a). Moves rather rapidly.
Cilia about 8 μm long in vivo, ordinarily spaced, arranged in an average of 12 longitudinal or slightly spiral, equidistant, ordinarily spaced rows more densely ciliated anteriorly than posteriorly (Figs 4a, d–f, h, i; Table 2). Dorsal brush heterostichad, occupies an average of 20% of body length, dikinetids widely spaced in vivo while ordinarily in protargol preparations due to the heavy shrinkage mentioned above. Rows 1 and 2 of nearly same length, row 1 composed of an average of seven dikinetids with a bristle anteriorly and a normal cilium posteriorly; row 2 composed of about eight dikinetids having two bristles with 2.5 μm each; row 3 about half as long as rows 1 and 2, composed of four to six dikinetids each having a 1.5 μm long bristle anteriorly and a 3 μm long bristle posteriorly; dikinetids of row 3 followed by four to five monokinetids with 1.5 μm long bristles (Figs 4a, b, e–h, g).
Oral bulge rather distinctly set off from body proper, about 4–5 μm across and 1–2 μm high in vivo, slightly depressed in centre (Figs 4a, d–i). Nematodesmata originate from oralized somatic monokinetids at anterior end of each ciliary row and from the circumoral dikinetids at base of oral bulge (Figs (Figs4g,4g, ,6g).6g). Details of oral structures recognizable in only few specimens.
To date found at type locality, as described above, and in tanks of Guzmania monostachia from the grounds of Marshall’s Pen, a Jamaican Great House close to Mandeville (parish Manchester), western Jamaica. Guzmania monostachia occurs in Jamaica and the Dominican Republic (Adams 1972).
Coriplites proctori differs from the congeners by the single, reniform macronucleus. It is easily confused with Pleuroplites australis Foissner, 1988 which, however, has a subapical extrusome bundle and a complex brush consisting of about eight rows. Likewise, it may be confused with Enchelys gasterosteus, as redescribed by Foissner et al. (1995), which, however, has 6–7 μm long extrusomes in the oral bulge.
Fuscheriidae with two dorsal brush rows. Oral extrusomes not recognizable by light microscopic means.
Apocoriplites lajacola nov. spec.
Composite of the Greek prefix apo (derived from), the Greek adjective coris (without) and the Greek noun hoplites (soldier), referring to the genus Coriplites and the lack of extrusomes, respectively. Masculine gender.
The oral basket of Apocoriplites lajacola consists of nematodesmata originating from monokinetids in the anterior region of the somatic kineties and from oral dikinetids, which are clearly separated from the somatic ciliary rows and thus form a distinct circumoral kinety. Accordingly, Apocoriplites belongs to the family Fuscheriidae as defined by Foissner et al. (2002), specifically, it is related to Coriplites which also lacks detectable extrusomes, differing mainly by the number of dorsal brush rows, viz., two vs. three. Admittedly, this is a rather inconspicuous generic feature which, however, likely represents a distinct evolutionary branch because the fairly large size of Apocoriplites lajacola excludes simple spatial constraints. The genus Apoenchelys is based on the same difference (Foissner et al. 2002). In Coriplites brush rows 2 and 3 are of similar composition and length as rows 1 and 2 in Apocoriplites, indicating loss of brush row 1 in the latter.
Size about 80 × 20 μm in vivo; cylindroidal to elongate bursiform. Two globular macronucleus nodules with a micronucleus in between. On average 12 ciliary rows, two anteriorly differentiated to an isostichad dorsal brush occupying about 23% of body length and composed of widely spaced dikinetids.
Mosses from a roadside Laja (granitic rock-pool) and from trees of a tropical dry forest (Selva Veranera) about 150 km NE of Puerto Ayacucho, Venezuela, E66°05′ N7°.
One holotype slide and 5 paratype slides with protargol-impregnated specimens have been deposited in the Biology Centre of the Museum of Upper Austria, Linz (LI). Relevant specimens are marked by black ink circles on the coverslip.
Named after the habitat found, i.e., granitic rock-pools called “Laja” in Venezuela.
Size 60–100 × 15–30 μm in vivo, usually about 80 × 20 μm, length:width ratio 3–6:1, on average 4:1 in protargol preparations (Table 3). Shape inconspicuous, cylindroidal, elongate bursiform or indistinctly obclavate; unflattened and acontractile (Figs 5a–d, 6a, b). Nuclear apparatus at or slightly posterior to mid-body, conspicuous because composed of two globular, almost abutting macronucleus nodules and a minute, globular micronucleus in between; nucleoli scattered, numerous, globular, rarely forming oblong or irregular masses (Figs 5a, c, d, ,6b;6b; Table 3). Contractile vacuole in rear end, several excretory pores in pole area. No extrusomes detectable by light microscopy. Cortex very flexible, contains about four narrowly spaced rows of granules between adjacent kineties, probably mucocysts because cells are enveloped in a thick, slightly agyrophilic layer in protargol preparations; individual granules rather refractive and about 1 (0.5 μm in size, thus forming distinct arrays (Figs 5e, g, h). Cytoplasm colourless, with some lipid droplets and food vacuoles 10–30 μm across, often containing almost intact small ciliates, mainly Drepanomonas revoluta and Leptopharynx costatus (Fig. 5a). Swims rather rapidly by rotation about main body axis.
Cilia about 8 μm long in vivo, ordinarily spaced, arranged in an average of 12 longitudinal, equidistant rows slightly more densely ciliated and indistinctly curved in anterior region (Figs 5a–f, 6a, e; Table 3). Dorsal brush occupies an average of 23% of body length, inconspicuous because bristles only up to 3 μm long; both rows of about same length and composed of an average of 10 widely spaced dikinetids in row 1 and of about 9 dikinetids in row 2; anterior tails composed of 1–2 monokinetids (Figs 5a, b, i, ,6a);6a); posterior region of row 2 heteromorphic in some specimens, that is, composed of dikinetids bearing a bristle and an ordinary cilium and monokinetids bearing ordinary cilia.
Oral bulge about 6 μm across and 2–3 μm high in vivo, small as compared to size of cell but fairly distinct because slightly set off from body proper and slightly depressed in centre (Figs 5a–f, 6b–e). Nematodesmata originate from about four oralized somatic monokinetids at anterior end of each ciliary row and from circumoral dikinetids at base of oral bulge, forming bundles sometimes crossing each other and extending to second third of body (Figs (Figs5e,5e, 6c, d). Circumoral kinety composed of slightly obliquely orientated dikinetids (Figs (Figs5f,5f, ,6e),6e), frequently with some irregularities, such as monokinetids and small, staggering fragments; irregularities possibly caused by a previous conjugation, as indicated by exconjugants with four globular macronucleus nodules in the protargol preparations.
As yet found only at type locality. Likely, it is a moss or soil species. Apocoriplites lajacola reached moderate abundance in the non-flooded Petri dish culture one month after rewetting the sample, indicating, that it is a k-selected species.
Apocoriplites lajacola is highly similar to Coriplites terricola, differing mainly by the number of dorsal brush rows (two vs. three); further, it is slightly larger (80 × 20 μm vs. 60 × 13 μm). Apocoriplites lajacola is not identical with any of the species compared by Foissner (1988) on occasion of the description of Coriplites terricola. As other coriplitids, Apocoriplites lajacola is rather easily identified in vivo by the lack of oral extrusomes and the distinct cortical granulation.
Financial support was provided by the Austrian Science Foundation (FWF, P-19699-B17) and the King Saud University. The technical assistance of Mag. Gudrun Fuss, Robert Schörghofer, and Andreas Zankl is greatly acknowledged. Special thanks to Dr. George R. Proctor, Jamaica, for taking us to rewarding collecting sites and identifying the bromeliad species.