Trochilia undetermined

Pan, Hongbo, Lin, Xiaofeng, Gong, Jun, Al-Rashied, Khaled A. S. & Song, Weibo, 2012, Taxonomy of five species of cyrtophorids (Protozoa: Ciliophora) including consideration of the phylogeny of two new genera, Zoological Journal of the Linnean Society 164 (1), pp. 1-17 : 7-11

TROCHILIA ALVEOLATA SP. NOV.

( FIG. 4 , TABLE 4)

Diagnosis: Small-sized Trochilia about 45–55 ¥ 15– 20 Mm in vivo; body outline elliptical, with five or six ridges on right side; cilium-free surface covered with a conspicuous alveolar layer; four right somatic kineties, the right-most two of which extend dorsoapically; two left frontal kineties which extend to about onethird of body length; podite caudally positioned.

Type deposition: The holotype, as a protargolimpregnated slide, has been deposited in the Laboratory of Protozoology , Ocean University of China (No. PHB10010703 ). A paratype slide is in the National History Museum , London, UK, with the registration number 2010:11:7:1 .

Type locality: Coastal waters off Clear Water Bay, Hong Kong (22°12′N, 114°117′E), water temperature 23 °C and salinity 16 ‰.

Etymology: The name refers to the feature of having distinct alveoli.

Description: Cell size about 55–45 ¥ 15–20 Mm in vivo, bilaterally flattened about 1:2. From side view, body elongated or oval in outline; left side flattened and right side vaulted with about five or six ridges. Anterior margin rounded and posterior slightly tapering ( Fig. 4A–C, F, K–M ). Pellicle of cilium-free field conspicuously covered with a thick alveolar layer that is composed of multiple vacuoles and detectable under 200 ¥ magnification ( Fig. 4F, L ). Podite slender, about 8 Mm long, caudally positioned. Cytoplasm colourless or greyish, usually with many tiny shining granules (1–2 Mm across) and one or two ingested diatoms, All measurements in Mm. Abbreviations: CV, coefficient of variation (%); EF, equatorial fragment; FvK, frontoventral kineties; Lf, left frontal kineties; Max, maximum; Mean, arithmetic mean; Min, minimum; N, number of specimens; SD, standard deviation; TF, terminal fragment.

which render the cell more or less opaque. Cytostome in anterior quarter of cell. Cytopharynx diagonally orientated, about 20 Mm long, and extending to about posterior fifth of cell, supported by two nematodesmal rods ( Fig. 4E ). Contractile vacuole not detected. Macronucleus ellipsoidal, size about 23 ¥ 13 Mm in vivo, centrally positioned, characteristically heteromerous. Micronucleus not detected. Cilia 8 Mm long in vivo. Movement always slow, by crawling on substrate.

Infraciliature as shown in Figure 4D, G, H, J, N . Four right kineties, the two right-most of which are almost equal in length (c. 147 kinetosomes) and both extend anteriorly and bend to dorsal side; the other two kineties shortened at both ends from right to left ( Fig. 4D, J, N ). At midbody about five closely spaced, very short left kineties. Two relatively long left frontal kineties, composed of 30–43 kinetosomes, positioned at the left side of cytostome, extending to about one-third of body length. One straight terminal fragment comprising three kinetosomes. Equatorial fragment consisting of about three kinetosomes.

Oral ciliature typical of the genus Trochilia ( Fig. 4D, G, N ): two parallel circumoral kineties and one short preoral kinety, all of which are composed of dikinetids.

Comparison and remarks: The genus Trochilia Dujardin, 1841 , is characterized by a combination of the following features: (1) lateral compressed but no ventral grooves; (2) two nematodesmal rods; (3) left field kineties divided into left kineties and left frontal kineties, the latter group always composed of two rows ( Heuss & Wilbert, 1973; Deroux, 1976c; Gong, Warren & Song, 2009b).

Amongst Trochilia species that have been described using modern methods, three species are similar to Trochilia alveolata sp. nov., Trochilia minuta (Roux, 1899) Kahl 1931 ; Trochilia petrani Dragesco, 1966 , and Trochilia sigmoides Dujardin, 1841 .

Trochilia petrani ( Fig. 5F ) resembles T. alveolata sp. nov. in terms of cell size, but it can be distinguished by the absence of both the alveolar layer and the ridges on right side (vs. present in latter) ( Dragesco, 1966).

Trochilia minuta and T. sigmoides are similar to the new species in terms of the presence of ridges on the right side. However, T. minuta ( Fig. 5D ) can be separated from T. alveolata sp. nov. by having relatively shorter left frontal kineties (containing c. six kinetosomes vs. 30–43 kinetosomes) and the absence of alveolar layer (vs. present in latter) ( Foissner, 1979). Compared with the new species, T. sigmoides ( Fig. 5A, B ) is smaller (20–28 vs. 45–55 Mm in length), oval in body outline (vs. elliptical) and has no alveolar layer (vs. present), and hence can be identified ( Gong et al., 2009b).

Trochilia marina Mereschkowski, 1881 , and T. salina Entz, 1879 , whose infraciliatures are not known, are also similar to T. alveolata sp. nov. in cell shape and marine habitat. The former ( Fig. 5E ) is characterized by smaller size (c. 33 vs. 45–55 Mm in length) and the absence of alveolar layer (vs. present in latter). The latter ( Fig. 5C ) can be identified from T. alveolata sp. nov. by smaller size (c. 20 vs. 45–55 Mm in length) and the absence of ridges on the right side (vs. present) ( Kahl, 1931).

Figures

Figure 4. Morphology and infraciliature of Trochilia alveolata sp. nov. from life (A–C, E, F, I, K–M) and after protargol impregnation (D, G, H, J, N). A, left lateral view of a typical individual. B, C, left views of different individuals. D, left lateral view to show infraciliature. E, to show details of oral apparatus structure, arrowheads mark nematodesmal rods. F, right lateral view to show the alveolar layer on the cell surface, arrows point to ridges. G, anterior part of cell. H, right lateral view, arrowheads refer to ridges on the surface. I, details of cell surface. J, right view of a small individual. K, left lateral view of a typical individual. L, right lateral view to show ridges and well-developed alveoli. M, left lateral view of a fat individual. N, left lateral view to show the infraciliature. Abbreviations: Co, circumoral kineties; Cy, cytopharynx; EF, equatorial fragment; FvK, frontoventral kineties; Lf, left frontal kineties; LK, left kineties; Ma, macronucleus; Pr, preoral kinety; TF, terminal fragment. Scale bars = 30 Mm (A–J), 25 Mm (K–N).

Figure 5. Congeners of Trochilia alveolata sp. nov. A, B, Trochilia sigmoides, from Gong et al. (2009b). C, Trochilia salina, from Kahl (1931). D, Trochilia minuta, from Foissner (1979). E, Trochilia marina, from Kahl (1931). F, Trochilia petrani, from Dragesco (1966). Scale bars = 10 Mm (D); 15 Mm (A, B); 20 Mm (C, E, F).