Spathidium bromelicola, Foissner & Wolf & Kumar & Quintela-Alonso, 2014

Foissner, Wilhelm, Wolf, Klaus W., Kumar, Santosh & Quintela-Alonso, Kuidong Xu and Pablo, 2014, Five New Spathidiids (Ciliophora: Bromeliads Haptoria) from Caribbean Tank, Acta Protozoologica 53, pp. 159-194 : 180-185

Spathidium bromelicola nov. spec. ( Figs 16a–k , 17a–

i, 18a–j ; Table 6)

Diagnosis: Size about 190 × 30 µm in vivo. Narrowly to very narrowly spatulate with steep to very steep, narrowly oblong oral bulge pointed ventrally and about 1.5 times as long as widest trunk region. Macronucleus long and tortuous; multimicronucleate. Extrusomes narrowly ovate to bluntly fusiform, about 4 × 0.8 µm in size. On average 20 ciliary rows, ventral and first left side row widely spaced anteriorly, producing an obtriangular, bare area in most specimens. Dorsal brush three-rowed, isostichad, occupies about 23% of body length; 25 widely spaced dikinetids in row 3. Type IV resting cysts.

Type locality: Tanks of bromeliads from the Botanical Garden on the Pico Isabel de Torres, north coast of the Dominican Republic, N19°45′ W70°42′ .

Type material: 1 holotype and 2 paratype slides with protargol-impregnated specimens have been deposited in the Biologiezentrum of the Oberösterreichische Landesmuseum in Linz ( LI), Austria. Relevant specimens have been marked by black ink circles on the coverslip .

Etymology: A noun in apposition composed of the plant family name Bromeliaceae and the adjectivally used Latin verb cola (dwelling in bromeliads).

Description: Size moderately variable, 150–250 × 25–40 µm in vivo, usually near 190 × 30 µm, as calculated from some in vivo measurements and the morphometric data, adding 15% for preparation shrinkage ( Table 6); length:width ratio 5.4–8.8: 1 in protargol preparations, on average near 6.5:1 both in vivo and prepared cells ( Table 6). Narrowly to very narrowly spatulate, rarely almost cylindroidal, only slightly widened in mid-body and thus almost parallel-sided; anterior (oral) end steeply to very steeply slanted, neck usually indistinct, posterior end ordinarily rounded; flattened only in hyaline oral region ( Figs 16a–c, g , 17a , 18a ). Macronucleus in central quarters of cell, frequently slightly nodulated and with strongly coiled ends, tortuous and longer than body when extended; contains many nucleoli up to 3 µm across. On average 11 globular micronuclei near and attached to macronucleus ( Figs 16a, g, h , 17a , 18a ; Table 6). Contractile vacuole in rear body end, some excretory pores scattered in pole area. Extrusomes studded in oral bulge and scattered in cytoplasm, narrowly ovate to bluntly fusiform and 3.5–4.5 × 0.7–1 µm in size ( Figs 16a, d–f , 18i, j ); do not impregnate with the protargol method used, not even the ends. Cortex very flexible and rather conspicuous due to highly refractive, densely spaced granules, forming about seven rows between each two kineties; individual granules about 0.5 µm across, colourless and compact. Cytoplasm colourless, contains few to many lipid droplets and, usually mainly in posterior half, many food vacuoles with remnants of heterotrophic flagellates. Glides rapidly on microscope slides and between mud particles, showing pronounced flexibility.

Somatic cilia about 9 µm long in vivo, arranged in an average of 20 ordinarily spaced, mostly bipolar, densely ciliated rows abutting on circumoral kinety in typical Spathidium pattern. Right side ciliary rows frequently attached to the individual circumoral kinetofragments; leftmost ventral and first left side ciliary row widely spaced anteriorly, producing a conspicuous, obtriangular, bare area in two thirds of 23 specimens analysed ( Figs 16a, g–i , 17a, d , 18a, d–f ; Table 6); the remainders have an additional ciliary row at this site. Dorsal brush almost exactly on dorsal side and almost perfectly isostichad, occupies an average of 23% of body length, inconspicuous because bristles only up to 3 µm long in vivo; all rows commence with some ordinary cilia anteriorly and continue as somatic kineties posteriorly ( Figs 16a, g–i , 17a, c, e , 18a, e ; Table 6). Brush row 1 composed of an average of 32 dikinetids, anterior bristle of dikinetids slightly clavate and about 3 µm long, posterior bristle rod-shaped and about 1.5 µm long. Brush row 2 slightly longer than rows 1 and 3, composed of an average of 39 rather narrowly spaced dikinetids associated with bristles similar to those described for row 1. Brush row 3 composed of an average of 25 comparatively widely spaced dikinetids, anterior bristle of dikinetids rod-shaped and about 2 µm long, posterior slightly clavate and about 2.5 µm long; posterior tail extends to second body third, conspicuous because heteromorphic, that is, composed of about 2 µm long bristles irregularly alternating with ordinary cilia ( Figs 16i , 17a ).

Oral bulge occupies anterior body end slanted by 50 to 80°, on average 1.5 times as long as widest trunk region; of ordinary distinctness, that is, about 4 µm high in vivo and with flat to moderately convex surface; oblong to narrowly oblong with more or less pointed ventral end; cytopharyngeal entrance marked by minute concavity near dorsal bulge end. Circumoral kinety of similar shape as oral bulge, usually continuous, composed of narrowly spaced dikinetids each associated with a cilium, a nematodesma, and a faintly impregnated fibre extending to oral bulge midline. Nematodesmata about 40 µm long, bundled and thus forming a fairly distinct oral basket ( Figs 16a–d, g–i , 17a, d, e , 18a, d–h ; Table 6).

Of 10 specimens isolated, eight commenced resting cyst formation after four days. Young cysts look like type I cysts, that is, have a ~ 0.5 µm thick, smooth wall touching the encysted cell. Two week-old cysts look different, representing a distinct type (see Foissner and Xu 2007 and Figs 17b , 18b, c ). They have two ~ 1 µm thick, smooth walls separated by a wide space, containing few to many lipid droplets highly similar to those found in the encysted cell. External wall on average 44 µm across (40–48 µm, n 8), with reddish shimmer and many circular diffraction lines. Internal wall 30 µm across (25–34 µm), with bluish shimmer in the bright field microscope, attached to encysted cell packed with lipid droplets 1–8 µm across and a bright blister, likely marking the contractile vacuole.

Occurrence and ecology: As yet found only at type locality, where it was rare in the non-flooded Petri dish culture. Whether or not S. bromelicola is specific to bromeliad tanks needs further investigations.

The type locality is on the Caribbean island Hispan- iola, which is divided politically in Haiti (east) and the Dominican Republic (west). The Pico Isabel de Torres is an about 800 m high mountain in the surroundings of the town of Puerto Plata on the north coast of the Dominican Republic. On the peak of the mountain there is a Botanical Garden with many small and middle-sized bromeliads on the trees of some forested areas. The mud and soil comprising the sample was collected from dry tanks of several bromeliad species and specimens and was used to set up a non-flooded Petri dish culture, as described in Foissner et al. (2002). The rewetted sample had pH 6.4 and a surprisingly high salinity of 8‰ (refractometer method) .

Remarks: The most similar species is possibly S. aciculare Foissner et al., 2002 ( Figs 17f–i ). However, it differs from S. bromelicola in the shape of the oral bulge (elongate elliptical vs. elongate cuneate) and the dorsal brush (heterostichad vs. isostichad). Take care not to confuse S. bromelicola with S. muscicola (extrusomes bluntly fusiform and about 4 µm long vs. rod-shaped and> 15 µm long), and, especially, with S. stammeri , which is very similar, except for the extrusomes (bluntly fusiform and about 4 µm long vs. rod-shaped and 8–12 µm long) and the spiny (vs. smooth) resting cyst ( Foissner and Xu 2007, Wenzel 1959).

Figures

Figs 16a–k. Spathidium bromelicola from life (a–f, j, k) and after protargol impregnation (g–i). a – left side view of a representative specimen, length 190 µm; b, c – shape variants; d, f – frontal view of oral bulge, showing the arrangement of the cortical granules and the extrusomes; e – oral bulge extrusomes, length 3.5–4.5 µm; g–i – left and right side view of holotype specimen, length 175 µm. The arrow marks the heteromorphic tail of brush row 3. The asterisk denotes the obtriangular space between the last ventral and the first left side ciliary row; j, k – surface view and optical section of cortex. B(1–3) – dorsal brush (rows), BA – oral basket, BU – oral bulge, CP – cytopharyngeal entrance, CV – contractile vacuole, E – extrusomes, EP – excretory pores, G – cortical granules, L – lipid droplet, MA – macronucleus, MI – micronuclei. Scale bars: 40 µm (h, i), 50 µm (g), and 70 µm (a).

Figs 17a–i. Spathidium bromelicola (a–e) and Spathidium aciculare (f–i, from Foissner et al. 2002) from life (b, c, f) and after protargol impregnation (a, d, e, g–i). a – right side view of a 200 µm long specimen with impregnated cilia, showing the heteromorphic tail of brush row 3 (arrowheads); b – resting cyst with inactive contractile vacuole, diameter 45 µm; c – posterior portion of dorsal brush, longest bristles 3 µm. The arrowhead denotes the heteromorphic, monokinetidal tail of brush row 3; d, e – ventral and dorsal views, showing the slightly cuneate oral bulge and the isostichad dorsal brush with dikinetids more widely spaced in row 3 than in rows 1 and 2. The asterisk marks the widened area between the last ventral and the first left side ciliary row; f – Spathidium aciculare, oral bulge extrusomes from two Australian populations, length 7–8 µm; g, h – Spathidium aciculare, left side and frontal view of anterior body region, showing the heterostichad dorsal brush and the elongate elliptical circumoral kinety (oral bulge); i – Spathidium aciculare, right side overview. B(1–3) – dorsal brush rows, BU – oral bulge, CK – circumoral kinety, CP – cytopharyngeal entrance, EP – excretory pores, L – lipid droplets, MA – macronucleus, MI – micronuclei. Scale bars: 30 µm (g, h), 40 µm (b, d, e), and 50 µm (a, i).

Figs 18a–j. Spathidium bromelicola from life (b, c, i, j) and after protargol impregnation (a, d–h). a – left side overview; b, c – resting cysts with large lipid droplets (arrowheads) between internal and external wall; d, f – right side views of oral body portion; e – left side view of oral body portion, showing the Spathidium ciliary pattern and the enlarged area (asterisk) between last ventral and first left side ciliary row; g, h – frontal views of the narrow oral bulge and its acute ventral end (g, arrowhead); i, j – oral bulge extrusomes, length about 4 µm. B – dorsal brush, BU – oral bulge, CK – circumoral kinety, MA – macronucleus, MI – micronuclei. Scale bars: 10 µm (g, h), 30 µm (d–f), 40 µm (b, c), and 50 µm (a).