Macrobiotus divergens Binda, Pilato & Lisi, 2005, sp. nov.
Creators: name: Binda, Maria Grazia
name: Pilato, Giovanni
name: Lisi, Oscar
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Tardigrada
Eutardigrada
Parachela
Macrobiotidae
Macrobiotus
Macrobiotus divergens

description: Macrobiotus divergens sp. nov. (Figs. 3, 4)
Type locality. New Zealand, North Island, Turangi (moss sample).
Material examined. New Zealand, North Island, Turangi: holotype and 4 paratypes.
New Zealand, North Island, Mt. Egmont National Park, the Plateau (1160 m): 4 specimens and one egg with fully developed embryo (partially hatched) from a moss sample. New Zealand, South Island, Temple Basin: 5 specimens from moss samples. Australia, New South Wales, New England National Park: 2 specimens from a lichen sample
Type repository. Museum of New Zealand Te Papa Tongarewa (Wellington).
Horning et al. (1978) attributed to M. furciger specimens and eggs of three different species. No specimen or egg we examined belongs to M. furciger. We here describe the new species M. divergens sp. nov. for specimens and eggs found in the above mentioned localities.
Description of the holotype. Body length 320 m; colourless; cuticle smooth; eyes absent (according to Horning et al., 1978). Buccopharyngeal apparatus of Macrobiotus type (Fig. 3 AC); mouth terminal with ten peribuccal lamellae; buccal cavity with an anterior band of small teeth, a posterior crown of triangular teeth and three dorsal and three ventral transverse ridges. Supplementary teeth seem to be absent. Buccal tube 39.3 m long and 4.6 m wide (pt = 11.7); stylet supports inserted on the buccal tube at 75.0 of its length (pt = 75.0). The stylet sheaths have peculiar characteristics: the lateral portion is very thick and the caudal portion is diverging from the buccal tube wall (Fig. 3 AB). On lateral view they appear drop­shaped (Fig. 3 C). Pharyngeal bulb (43.1 m x 39.3 m) with apophyses, three rod­shaped macroplacoids and small microplacoid. First macroplacoid 5.6 m long (pt = 14.2), second 4.7 m (pt = 12.0), third, with a preterminal narrowing, 4.8 m (pt = 12.2), microplacoid 3.0 m long (pt = 7.6). Entire placoid row 19.9 m (pt = 50.6), macroplacoid row 16.6 m (pt = 42.2).
The claws, of the hufelandi type, are short and stout with well developed accessory points on main branches (Fig. 3 D, E). Internal and external claws of the third pair of legs are 8.3 m (pt = 21.1) and 8.7 m long (pt = 22.1) respectively; the anterior and posterior claws of the hind legs are 10.2 m (pt = 25.9) and 10.9 m long (pt = 27.7) respectively. Smooth lunules are present on all legs. A cuticular thickening present near the lunules on the first three pairs of legs.
Together with the specimens attributable to this species, in a moss sample from Mt. Egmont National Park, one egg with the newborn partially hatched has been found (Fig. 4 A). This egg, freely laid, is spherical with some spaced processes (17 in the circumference); the diameter is 69 m excluding the processes, 80 m processes included. The processes (Fig. 4 B) are subdivided generally twice from half process length; some of them divided thrice but the terminal branches are very short; each subdivision may be dichotomic or multiple, i.e., two or more branches may be formed. Processes' surface smooth without refracting areas. They are 4.7–4.8 m high, the basal diameter 5.7–6.3 m. Their bases have some projections that delimitate a basal crown of meshes. Egg shell with a delicate but evident reticular sculpture; margins of the meshes very thin (Fig. 4 B).
The paratypes are similar to the holotype for both qualitative and quantitative characters. In Table 1 the dimensions of some structures of the smallest and the largest measured specimens are indicated. We measured the value of the index pt relative to the stylet supports in 9 specimens, two newborns included; the minimum and maximum values were 74.9 and 77.5 respectively.
Etymology. The name divergens refers to the aspect of the stylet sheaths that both on dorsal or ventral view appear diverging from the buccal tube walls.
Remarks. Macrobiotus divergens sp. nov. differs from M. furciger in the following features: eyes absent (according to Horning et al., 1978); buccal tube slightly wider in relation to the body length (Table 1); stylet sheaths very thick and with the caudal portion diverging from the buccal tube walls; third macroplacoid about as long as the first one; microplacoid shorter (Table 1); claws shorter (Table 1); and in some characters of the eggs (smaller dimensions; processes shorter, less numerous, more spaced, without refracting areas; basal projections longer that do not appear as a crown of basal dots; reticular design of egg shell with larger meshes with thinner margins).
The new species differs from M. aradasi sp. nov. in the following features: eyes absent (according to Horning et al., 1978); buccal cavity with anterior band of teeth present; posterior portion of buccal cavity wider; stylet sheaths very thick and with the caudal portion diverging from the buccal tube walls; stylet supports inserted on the buccal tube in a more caudal position (Table 1); claws shorter (Table 1); and in some characters of the eggs (smaller dimensions; processes shorter; with thinner branches; basal projections longer that do not form a crown of basal dots; reticular design of egg shell with larger meshes with thinner margins).
description: Published as part of 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), pp. 55-68 in Zootaxa 1075 on pages 62-64, DOI: 10.5281/zenodo.273289