Macrobiotus sicheli, Binda, Maria Grazia, Pilato, Giovanni & Lisi, Oscar, 2005

Binda, Maria Grazia, Pilato, Giovanni & Lisi, Oscar, 2005, Remarks on Macrobiotus furciger Murray, 1906 and description of three new species of the furciger group (Eutardigrada, Macrobiotidae), Zootaxa 1075, pp. 55-68 : 65-67

Macrobiotus sicheli sp. nov. ( Fig. 5 )

Type locality. South Africa, Tzitzikama (an undetermined moss sample).

Material examined. South Africa, Tzitzikama: holotype, 29 paratypes and 7 eggs.

Type repository: Collection of Binda and Pilato: Department of Animal Biology “Marcello La Greca”, University of Catania.

Binda (1984) attributed to M. furciger specimens and eggs from South Africa; some differences with respect to the description of this species were attributed to the individual variability. We compared the material from South Africa with specimens of M. furciger from the South Georgia described above, and noted some differences that induce us to attribute the South African specimens to a new species here described and named M. sicheli sp. nov.

Description of the holotype. Body length 329 m; colourless, eyes present, cuticle with small dots difficult to see ( Fig. 5 C). Buccopharyngeal apparatus of Macrobiotus type ( Fig. 5 A); mouth terminal with ten peribuccal lamellae; buccal cavity wall with an anterior band of fine teeth, a posterior crown of triangular teeth and three dorsal and three ventral transverse ridges. Also some supplementary teeth present. Buccal tube 45.4 m long and 8.3 m wide (pt = 18.3). Stylet supports inserted on the buccal tube at 80 % of its length (pt = 80). The pharyngeal bulb (46.3 m x 32 m) has pharyngeal apophyses, three rod­shaped macroplacoids and microplacoid. First macroplacoid 7.4 m long (pt = 16.3), second 6.1 m (pt = 13.4), third, with a preterminal narrowing, 7.3 m (pt = 16.1), microplacoid 5.2 m long (pt = 11.4); entire placoid row 27.7 m long (pt = 61.0), macroplacoid row 21.8 m long (pt = 48.0).

The claws, of the hufelandi type, are short with accessory points on main branches ( Fig. 5 B). External claws of third pair of legs 9.5 m long (pt = 20.9). The unfavourable orientation does not allow measurement of other claws; in Table 1 the length of claws of a paratype 230 m long is indicated. Smooth lunules are present; a cuticular thickening is present near the lunules on the first three pairs of legs.

The eggs ( Fig. 5 D, E), freely laid, are spherical with trunco­conical processes with the extremity divided (the division may be dichotomic or multiple); the diameter is 66–85.5 m excluding the processes, 82–95 m including them. The processes, 15–23 in the circumference, have a large basal portion and a narrower terminal portion divided twice or thrice (more rarely once) at the apex; the branches are therefore short, and the terminal branches very short ( Fig. 5 D). Process surface smooth without refracting areas. The processes in the largest measured egg are 6.5–7.8 m high, the basal diameter in the same egg is 7.9–12.2 m .. The base of each process has a crown of projections forming a very evident crown of dots. The egg shell is dotted; some dots may be contiguous to one another and form a trace of an irregular reticular design ( Fig. 5 E).

Etymology. The name sicheli is in honour of Prof. Giovanni Sichel, cellular biologist of University of Catania and our friend.

Remarks. Macrobiotus sicheli sp. nov. differs from M. furciger in the following features: cuticle finely dotted; wider buccal tube ( Table 1 ); stylet supports inserted on the buccal tube in a more caudal position (pt = 79.3–80.0 in M. sicheli sp. nov., 76.2–77.1 in M. furciger ); third macroplacoid about long as the first one ( Table 1 ); claws shorter ( Table 1 ); accessory points less developed; and in some characters of the egg (smaller dimensions; processes shorter, without refracting areas, divided only in the terminal portion and therefore with branches shorter; basal crown of projections more evident; egg shell with more evident dots but without a true, regular, reticular design).

The new species differs from M. aradasi sp. nov. in the following features: cuticle finely dotted; buccal armature with anterior band of teeth present; posterior crown of teeth more developed; wider buccal tube ( Table 1 ); stylet supports inserted on the buccal tube in more caudal position (pt = 79.3–80.0 in M. sicheli sp. nov., 72.0– 72.8 in M. aradasi sp. nov.); microplacoid slightly longer ( Table 1 ), claws shorter ( Table 1 ) with accessory points less developed; and in some characters of the eggs (egg processes divided only in the terminal portion and therefore with branches clearly shorter; basal projections forming a more evident basal crown of dots; egg shell with more evident dots but without a true, regular, reticular design).

Macrobiotus sicheli sp. nov. differs from M. divergens sp. nov. in the following features: cuticle finely dotted; eyes present; stylet sheaths normally shaped, i.e., not very thick and with the caudal portion not diverging from the buccal tube walls; stylet supports inserted on the buccal tube in a more caudal position (pt = 79.3–80.0 in M. sicheli sp. nov., 74.9–77.5 in M. divergens sp. nov.); microplacoid more developed ( Table 1 ); claws with accessory points less developed; and in some characters of the eggs (processes more developed, divided only in the terminal portion and therefore with branches shorter; basal projections more developed and forming a more evident crown of basal dots; egg shell with more evident dots but without a true, regular, reticular design).

Figures

FIGURE 5. Macrobiotus sicheli sp. nov.: A, buccopharyngeal apparatus of the holotype; B, claws of the third pair of legs; C, cuticular dots, and claws of the fourth pair of legs of the holotype; D, egg; E, detail of the egg shell ornamentation. (Scale bar = 10 m)