Spathidium wolfi, 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 (2), pp. 159-194 : 187-193

Spathidium wolfi nov. spec. ( Figs 19a–l , 20a–f , 21a–c ,

22a–k ; Table 7)

Diagnosis: Size about 135 × 25 µm in vivo. Very narrowly spatulate to bluntly fusiform with oblique, cuneate oral bulge half as long as widest trunk region. Macronucleus moniliform, composed of an average of 8 ellipsoidal nodules; multimicronucleate. Two contractile vacuoles, one dorsally at margin of first and second body third, the other in rear end. On average 15 ciliary rows, 3 of them differentiated to isostichad, short dorsal brush occupying 19% of body length; 14 widely spaced dikinetids in row 3.

Type locality: Tanks of terrestrial bromeliads at the foot of Mt. Diablo, northwest of Spanish Town, Jamaica, N18° W77° .

Type material: 1 holotype and 3 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 .

Dedication: The senior author dedicates this new species to Dr. rer. nat. habil. Klaus W. Wolf, Electron Microscopy Unit at the University of the West Indies, Kingston, Jamaica, who facilitated collection on the island.

Description: Size 100–160 × 18–35 µm in vivo, usually near 135 × 25 µm. Narrowly to very narrowly spatulate to bluntly fusiform, especially in preparations containing many specimens with inflated middle body third; length:width ratio thus rather different in vivo (~ 5.5:1) and preparations (~ 4:1). Neck indistinct, widest usually in middle body third, body ends up to 2:1 flattened. Anterior (oral) end oblique, posterior narrowly rounded ( Figs 19a, e , 20a, b, e , 22a–d ; Table 7). Macronucleus in middle body third, moniliform assuming various figures ranging from cylindroidal to circular, composed of an average of eight nodules connected by narrow bridges; individual nodules globular to elongate ellipsoidal, contain many small nucleoli. Micronuclei near and attached to macronucleus, inconspicuous, that is, about 2 µm across in protargol preparations ( Figs 19a , 20a, e , 21b , 22a–d ; Table 7). Two contractile vacuoles, each with adventive blisters during diastole ( Figs 19a, e , 20a, e , 21a, b , 22b, c ; Table 7): one dorsally at margin of first and second body third, the other in rear end, as usual. Anterior vacuole with an average of three serially arranged excretory pores invariably locat- ed between kineties differentiated to dorsal brush rows 2 and 3 anteriorly. Extrusomes studded in oral bulge and scattered in cytoplasm, where intensely impregnated, fusiform developmental stages occur ( Fig. 19d ); oral bulge extrusomes rod-shaped to indistinctly acicular and slightly curved, about 10 × 0.5 µm in size ( Figs 19a–c ); do not impregnate with the protargol method used. Cortex flexible, jelly-like, and about 1 µm thick, contains about six rows of colourless, very narrowly spaced granules between each two kineties; individual granules about 0.2 µm across, frequently impregnate with protargol obscuring ciliary pattern ( Figs 19g, h , 22h ). Cytoplasm usually dark postorally due to many highly refractive lipid droplets up to 2 µm across and/ or circular structures (“Ringgranula”) 1.5–2 µm across. Ringgranula develop from globular precursors and do not dissolve when freed from cell; do not impregnate or dissolve with the protargol method used ( Figs 19a, f ). Food not known. Movement without peculiarities.

Cilia about 10 µm long in vivo, arranged in an average of 15 equidistant, usually bipolar, ordinarily spaced and ciliated rows abutting on circumoral kinety in fairly indistinct Spathidium pattern because ventral half kineties lack polymerized kinetids anteriorly and do not abut on circumoral kinety ( Figs 19k, l , 20a, b, d–f , 22k ; Table 7). Dorsal brush of ordinary structure and distinctness, occupies about 19% of body length, bristle details difficult to recognize in vivo due to the highly refractive cytoplasmic inclusions. Brush rows isostichad, each with distinct anterior tail and likely structured as shown in Fig. 20c , that is, with some 5–6 µm long bristles in posterior half; row 1 composed of an average of 16 dikinetids, row 2 of 18, and row 3 of 14 ( Figs 19a, i–k , 20a, e, f , 21a–c , 22b, k ; Table 7).

Oral bulge occupies anterior body end slanted by 45° to 60°, on average half as long as widest trunk region in inflated protargol-impregnated specimens (see above), while about as long as trunk width in vivo; of ordinary distinctness in lateral view, that is, about 4 µm high and with flat to slightly convex surface, while con- spicuously obovate to cuneate in frontal view ( Figs 19b , 20d , 22e–g ), a rare shape in Spathidium s. str.; contains rather thick fibres originating from circumoral dikinetids; cytopharyngeal entrance not recognizable. Circumoral kinety of same shape as oral bulge, continuous but occasionally with a minute gap ventrally, similar as in Apertospathula ( Fig. 20d ); composed of about 40–80 dikinetids each associated with a cilium, an oral basket rod, and a distinct fibre extending into oral bulge cortex, as described above. Nematodesmata fairly distinct, form small bundles slightly longer than dorsal brush; oral basket thus rather distinct in appropriately impregnated specimens ( Figs 19a, i–l , 20a, b, d, f , 22e–k ; Table 7).

Occurrence and ecology: As yet found at type locality and in a granitic rockpool (Laja) near to the town of Pto. Ayachuco, Venezuela, where a single specimen is contained in the type slides of Apertospathula lajacola , indicating wide distribution in Central and South America. Further studies are required to determine the extent the species is specific to bromeliad tanks. Num- bers were very low in the fresh sample, but after addition of a squashed wheat grain they multiplied rapidly for some days; however, efforts to establish pure cultures failed .

Remarks: Within the genus, S. wolfi and S. faurefremieti Foissner (2003) form a distinct subgroup characterized by two contractile vacuoles and a cuneate oral bulge. If further such species are discovered, they should be separated at subgeneric rank, at least. Actually, S. wolfi looks like a small S. faurefremieti but differs in body size (135 × 25 µm vs. 240 × 17 µm), macronucleus (moniliform vs. a long, tortuous strand), and the total number of brush bristles (about 47 vs. 72).

Figures

Figs 19a–l. Spathidium wolfi from life (a–h) and after protargol impregnation (i–l). a – right side view of a representative specimen, length 140 µm. The arrowhead marks the anterior contractile vacuole; b – frontal view of oral bulge; c – oral bulge extrusomes, length 10 µm; d – developing extrusomes in the cytoplasm; e – slender shape variant, showing the two contractile vacuoles (arrowheads); f – development of the “Ringgranula” (cp. Fig. 19a); g, h – surface view and optical section, showing the cortical granulation; i, j – ventral and dorsal view of anterior body region of a paratype specimen, showing the isostichad dorsal brush and the cuneate oral bulge; k, l – right and left side view of anterior body region of the holotype specimen (cp. Figs 20a, b). B(1–3) – dorsal brush rows, BA – oral basket, BU – oral bulge, CK – circumoral kinety, E – extrusomes, F – oral bulge fibres, G – cortical granules, L – lipid droplet, MA – macronucleus, RG – “Ringgranula”. Scale bars: 15 µm (i–l) and 50 µm (a).

Figs 20a–f. Spathidium wolfi from life (c) and after protargol impregnation (a, b, d–f). a, b – ciliary pattern of right and left side and nuclear apparatus of holotype specimen; for oral details, see Figs 19k, l. The arrowhead marks the excretory pores of the anterior contractile vacu- ole, i.e., the main character of this species; c – supposed structure of dorsal brush row 3; d – ventral view of a paratype specimen with open circumoral kinety (arrow) and thus resembling Apertospathula; e – dorsolateral view of a paratype specimen, showing the ciliary pattern and the excretory pores of the anterior and posterior contractile vacuole; f – ventrolateral view of oral body region, showing the Spathidium ciliary pattern. B(1–3) – dorsal brush (rows), BU – oral bulge, CK – circumoral kinety, CV – contractile vacuole, EP – excretory pores, MA – macronucleus, MI – micronuclei. Scale bars: 10 µm (d, f) and 50 µm (a, b, e).

Figs 21a–c. Spathidium wolfi, dorsal views of anterior body region after protargol impregnation, showing the isostichad dorsal brush (c, arrows) and the excretory pores (arrowheads) of the anterior contractile vacuole. B(1–3) – dorsal brush rows, BU – oral bulge, CK – cir- cumoral kinety, MA – macronucleus. Scale bars: 20 µm.

Figs 22a–k. Spathidium wolfi after protargol impregnation. a – a slender specimen; b – overview of a specimen inflated by the prepara- tion; c, d – overviews showing the moniliform macronucleus; e–g – ventral views, showing the obovate (or broadly cuneate) circumoral kinety; h – ventrolateral view, showing kineties and cortical granules; i–k – anterior body portion at three focal planes. (i) Right side surface view, showing fibres in oral bulge and somatic cortex (arrowheads). (j) When focused slightly deeper, the nematodesmata become visible. (k) When focused to the left side, the dorsal brush and the Spathidium ciliary pattern become recognizable. B(1–3) – dorsal brush (rows), BU – oral bulge, CK – circumoral kinety, E – extrusomes, EP – excretory pores, F – fibres, G – cortical granules, K – kineties, MA – mac- ronucleus, MI – micronuclei, N – nematodesmata. Scale bars: 10 µm (e–k) and 50 µm (a–d).