Eremobiotus ginevrae, Lisi, Oscar, Binda, Maria Grazia & Pilato, Giovanni, 2016

Lisi, Oscar, Binda, Maria Grazia & Pilato, Giovanni, 2016, Eremobiotus ginevrae sp. nov. and Paramacrobiotus pius sp. nov., two new species of Eutardigrada, Zootaxa 4103 (4), pp. 344-360 : 345-349

Eremobiotus ginevrae sp. nov.

( Figs. 1 , 2 )

Type locality: Turcisi Mount, (Sferro, Castel di Judica, Sicily), 37°30′03″ N 14°47′ 50″E. Mosses on clay at 78 m a.s.l. collected by Vera D’Urso in May 2006.

Material examined. Holotype (slide no. 5530) and 7 paratypes from the same locality (slides nos. 2388-91, 5528, 5529, 5531-5535). In addition to this material, we examined paratypes, preserved in the Binda and Pilato collection, from the following Sicilian localities: Nebrodi Mountains: Torrente della Saracena, Sicily (3 specimens, slides nos. 5543-5544); Simeto River: Adrano, Sicily (5 specimens, slides nos. 1704-1708). Other material examined: Etna, Zafferana Etnea: Piano d’Api, Sicily (1 specimen, slide no. 969); Madonie: Gangivecchio, Sicily (4 specimens, slides nos. 5537, 5561-63); in addition, we examined specimens from Israel: one specimen Mt. Hermon (slide no. 5327), 3 specimens from Jerusalem: Sanhedria (slides nos. 5328–5330) kindly sent by Chanan Dimentman and Heather Schnur (University of Jerusalem), and one specimen from Russia: Novocherkassk (Rostov-on-Don district) (slide no. 3358) (kindly sent by Vladimir Biserov).

Specific diagnosis. Colourless, cuticle smooth; eye spots present in the examined living specimens; buccopharyngeal apparatus of the Isohypsibius type; peribuccal lamellae absent; pharyngeal bulb with two macroplacoids; microplacoid absent. External claws of the first three pairs of legs of the Isohypsibius type; internal claws of the same type but modified as regards the angle between the main and the secondary branches, it being clearly wider than in the typical Isohypsibius type. Both anterior and posterior claws of the hind legs more greatly modified, which is a character of the genus: the two branches of each claw are joined in a long basal portion of their length, constituting a wide triangular common tract from which the terminal portions of the branches diverge with an angle of almost 180°. Claw accessory points of legs I–III without a visible free portion emerging from the main branches; whereas accessory points of the hind leg claws, in comparison very evident. Lunules on the first three pairs of legs smooth; those on the hind legs with small marginal teeth. A long, cuticular bar is present on the first three pairs of legs. Eggs smooth laid in the exuviae.

Description of the holotype. Body length 308 µm; colourless; eye spots present before mounting; cuticle smooth.

Isohypsibius type bucco-pharyngeal apparatus ( Fig. 1 A,B), i.e. with rigid buccal tube, without ventral lamina and with dorsal and ventral apophyses for the insertion of the stylet muscles in the shape of ridges symmetrical with respect to the frontal plane ( Fig. 1 B).

Mouth without peribuccal lamellae; three dorsal and three ventral thin transverse ridges and a band of extremely small teeth present in the caudal portion of the oral cavity ( Fig. 1 A); no teeth are visible in the anterior portion of the oral cavity. Buccal tube 34.0 µm long and 5.7 µm wide externally (pt = 16.8); stylet supports inserted on the buccal tube at 70.0% of its length (pt = 70.0). Pharyngeal bulb with caudally forked apophyses and two macroplacoids, the first of which with a marked central narrowing ( Fig. 1 A,B) and the second with a pre-terminal narrowing. First macroplacoid 7.8 µm long (pt = 22.9), second 5.0 µm (pt = 14.7), entire placoid row 14.0 µm long (pt = 41.2).

External claws of the first three pairs of legs of the Isohypsibius type ( Figs.1 A,C and 2AB); the internal claws are modified in that the angle between the main and secondary branches is greater than in the typical Isohypsibius type claws. Both anterior and posterior claws of the hind legs more greatly modified as is characteristic of the genus: the two branches of each claw are joined to one another for a long portion of their length, constituting a wide, triangular common tract from which the terminal portions of the branches diverge with an angle of almost 180° ( Figs.1 D and 2C,D). External claws of the third pair of legs 12.6 µm long (pt = 37.1); internal claws on the same pair of legs 10.4 µm long (pt = 30.6); posterior claws of the hind legs 12.1 µm long (pt = 35.6). Anterior claw of the same pair of legs 11.5 µm long (pt = 33.8). Claw accessory points on legs I–III without free emerging portion from the main branches ( Figs. 1 C and 2 A,B) while short, but very evident accessory points are present on the main branches of the claws of the hind legs ( Figs. 1 D, arrow a, and 2C,D, arrow a). Lunules present, small and with smooth margin on the first three pairs of legs ( Figs. 1 C, arrow a, and 2A, arrow a); more developed and with small marginal teeth on the hind legs ( Figs. 1 D, arrow b, and 2C,D, arrow b). A well developed, very long, cuticular bar is present on the first three pairs of legs ( Figs.1 C, arrow b, and Fig. 2 A,B, arrow b).

Remarks. The paratypes are similar to the holotype in both morphological and metric characters; the measurements of some structures of the holotype six paratypes are given in Table 1 .

Eremobiotus ginevrae sp. nov

Eggs: The eggs are smooth, laid in the exuviae (we counted up 7 eggs, but we cannot exclude higher numbers in other exuviae).

Etymology. The specific name ginevrae is in honour of the young dear grandchild, Ginevra, come to delight her grandparents Maria Grazia and Giovanni.

Differential diagnosis. Previously, only two species had been attributed to the genus Eremobiotus : Eremobiotus alicatai and Eremobiotus ovezovae .

The new species differs from Eremobiotus alicatai by having longer claws ( Table 2 ); both external and internal claws, on the first three pairs of legs, with longer terminal portions of the main branches and, as a consequence, the claws of Eremobiotus ginevrae sp. nov. appear to be more slender ( Figs. 2 A,B and 3D); the claws of the hind legs have a shorter common tract and the free portion of the branches appear to be longer ( Figs. 1 D and 3C); the free portion of the accessory points of claws I–III are not visible in Eremobiotus ginevrae sp. nov. ( Fig. 2 A,B) whereas they are in Eremobiotus alicatai ( Fig. 3 D, arrow a); on legs IV the accessory points are very obvious but less developed than in Eremobiotus alicatai . The lunules of the first three pairs of legs are smooth and those of the hind legs have less developed marginal teeth, whereas in Ermobiotus alicatai all lunules have marginal teeth.

The new species differs from Eremobiotus ovezovae by having a smooth cuticle, eye spots present, longer and wider buccal tube ( Table 2 ; Figs. 1 A and 4A), clearly longer, differently shaped claws ( Table 2 ; Figs. 1 A,C,D and 4B-E) and the free portion of the accessory points not visible on the claws of legs I–III.

Figures

FIGURE 1. Eremobiotus ginevrae sp. nov.: A. Bucco-pharyngeal apparatus of the holotype. B, Bucco-pharyngeal apparatus, in lateral view, of a paratype (slide no. 5327). C, Claws of the third pair of legs of the holotype (arrow ‘ a’ indicates a lunule; arrow ‘ b’ the long cuticular bar near the base of the internal claw). D, Claws of the hind legs of the holotype (arrow ‘ a’ indicates an accessory point; arrow ‘ b’ indicates a lunule). Scale bar = 10 µm.

FIGURE 2. Eremobiotus ginevrae sp. nov.: A, Claws of the third pair of legs of a paratype (slide no. 5544); free accessory points are absent. A long cuticular bar (arrow ʽbʼ) is visible near the lunule at the base of internal claw (arrow ʽaʼ). B, Claws of the third pair of legs of a paratype (slide no. 1707); free accessory points are absent (arrow ʽaʼ: indicates a lunule; arrow ʽbʼ: the long cuticular bar near the base of the internal claw). C, Claws of the hind legs of a paratype (slide no. 2389); the well developed accessory points are visible (arrow ʽaʼ); arrow ʽʼbʼ: indicates a lunule. D, Claws of the hind legs of a paratype (slide no. 5327); the accessory points (arrow ʽaʼ) and the lunules (arrow ʽbʼ) are visible. Scale bar = 10 µm.

FIGURE 3. Eremobiotus alicatai: A, Bucco-pharyngeal apparatus of the holotype (slide no. 960). B, Claws of the second pair of legs of the holotype. C, Claws of the hind legs of the holotype. The arrow indicates a lunule. D, Claws of the third pair of legs of a paratype (slide no. 2053). Arrow ʻaʼ: indicates an accessory point; arrow ʻbʼ: indicates the long cuticular bar near the base of the internal claw. Scale bar = 10 µm.

Tables

TABLE 1. Eremobiotus ginevrae sp. nov.: Measurements in Μm and pt index values relative to some structures for the holotype and six paratypes.

Slide number	5535	2388	5529	2391	5528	5530	2389
			paratypes			holotype	paratype
Body length	221	about 230	230	248	about 250	308	360
Buccal tube length	27.3	26.1	27.2	27.3	29.0	34.0	33.4
External buccal tube width	3.9	3.6	3.8	3.6	4.3	5.7	5.7
pt	14.3	13.8	14.0	13.2	14.8	16.8	17.1
pt Stylet supports insertion point	71.2	71.1	70.9	70.2	71.0	70.0	69.5
First macroplacoid	5.6	5.8	6.0	5.7	?	7.8	8.2
pt	20.5	22.2	22.1	20.7	?	22.9	24.6
Second macroplacoid	3.6	3.6	3.8	3.6	?	5.0	4.9
pt	13.2	13.8	14.0	13.2	?	14.7	14.7
Macroplacoid row	9.9	9.6	9.6	9.6	?	14.0	14.5
pt	36.3	36.8	35.3	35.2	?	41.2	43.4
External claw I	8.9	7.7	?	?	?	?	?
pt	32.6	29.5	?	?	?	?	?
Internal claw I	6.8	6.3	6.6	6.9	7.7	9.6	?
pt	24.9	24.1	24.3	25.3	26.6	28.2	?
External claw II	?	8.0	?	?	?	?	?
pt	?	30.6	?	?	?	?	?
Internal claw II	8.1	6.5	7.8	7.4	8.0	10.4	?
pt	29.7	24.9	28.7	27.1	27.6	30.6	?
External claw III	9.4	8.2	8.9	?	?	12.6	?
pt	34.4	31.4	32.7	?	?	37.1	?
Internal claw III	8.1	6.9	8.1	8.3	?	10.4	9.4
pt	29.7	26.4	29.8	30.4	?	30.6	28.1
Posterior claw IV	?	?	?	10.0	?	12.1	11.6
pt	?	?	?	36.6	?	35.6	34.7
Anterior claw IV	?	?	?	9.0	8.4	11.5	?
pt	?	?	?	32.3	29.0	33.8	?