Platicrista horribilis, Kaczmarek & Michalczyk, 2003

Kaczmarek & Michalczyk, 2003, Platicrista horribilis, a new species of Tardigrada (Eutardigrada: Hypsibiidae) from Mongolia, Zootaxa 132, pp. 1-8 : 2-7

Platicrista horribilis sp. nov.

( Figs 1­5 )

Description

Holotype: Total body length 720 m ( Fig. 1 ). Body white or transparent. Cuticle smooth. Eyes absent. Buccopharyngeal tube 76 m long and 3 m wide. Apophyses for insertion of stylet muscles very wide, with a flat ridge. Drop­like thickening between buccal and pharyngeal tube absent. Buccal tube 39 m long. Pharyngeal tube with spiral thickening 37 m long, ending (on dorsal or ventral view) with semilunar structures (4 m long). In pharynx, between end of pharyngeal tube and the first macroplacoid two very slender cuticular bars directed forward (5 m long). Stylet supports inserted 1 m above upper limit of pharyngeal tube. Pharyngeal bulb pear­shaped, 77 m long and 37 m wide, containing two slender, lancet­shaped macroplacoids with irregularly undulated edges. First macroplacoid 14 m, second 33 m long; both 1 m wide. Macroplacoid row 48 m long. Septulae and microplacoid absent ( Figs 2­3 ). Claws of Hypsibius ­ type; on I pair of legs: external (primary branch: 30 m, secondary: 13 m), internal (pb.: 17 m, sb.: 10 m); II: ext. (pb.: 33 m, sb.: 15 m), int. (pb.: 20 m, sb.: 12 m); III: ext. (pb.: 34 m, sb.: 14 m), int. (pb.: 22 m, sb.: 12 m); VI: ext. (pb.: 34 m, sb.: 16 m), int. (pb.: 23 m, sb.: 14 m). Primary branches of internal and external claws with two accessory points. On IV pair of legs lunules with fine teeth. Cuticular bars on legs absent ( Figs 4­5 ). Eggs unknown.

Measurements of some structures of holotype and two paratypes are shown in Tab. 1 .

Remarks

There is visible fine granulation on IV pair of legs in paratype 1. Very slender cuticular bars are orientated backwards in paratype 1 (probably caused by preparation); in paratype 2 only one of these structures is visible. In some cases the teeth on lunules may resemble knobs.

Type locality

Northern Mongolia; Archangaj Ajmag, Tehijn Cagan Nuur National Park; Tarbagataj Mts.; 2700 m; mosses from rocks; VII 2000; leg. oe. Kaczmarek.

CHARACTER HOLOTYPE PARATYPE 1 PARATYPE 2 AVERAGE CHARACTER HOLOTYPE PARATYPE 1 PARATYPE 2 AVERAGE Material examined

Holotype is preserved at the Zoological Museum of Jagiellonian University, ul. Ingardena 6, 30­060 Kraków, Poland; paratype 1 is preserved at the Department of Animal Taxonomy and Ecology, A. Mickiewicz University, Poznañ; paratype 2 is preserved in the collection of oe. Michalczyk (Jagiellonian University).

Differential diagnosis

Platicrista horribilis is similar to P. affine (Mihelcic, 1951) and P. angustata (Murray, 1905) however, it is easily distinguishable by the presence of teeth on the lunules of the IV pair of legs (it was not mentioned in the description by Ramazzotti & Maucci (1983), however, the dilated bases are smooth in the drawings).

The new species differs from P. itaquasconoide (Durante & Maucci, 1975) by lacking the microplacoid, small basal spur of the claw on the IV pair of legs and by having a narrower buccal tube (8 m in P. itaquasconoide ).

Platicrista horribilis differs from P. cheleusis Kathman, 1990 by lacking the polygonal pattern on cuticle and cuticular bars on legs.

Figures

FIGURE 1. Platicrista horribilis sp. nov. 1, habitus (drawn from Phase Contrast Microscope).

FIGURES 2 ­ 3. Platicrista horribilis sp. nov. 2 ­ 3, buccal apparatus (2, middle section); (3, ventral section) (drawn from Phase Contrast Microscope).

FIGURES 4 ­ 5. Platicrista horribilis sp. nov. 4, claws of the IV pair of legs (drawn from Phase Contrast Microscope), 5, internal claw of the IV pair of legs (Nomarski Differential Interference Contrast Microscope).

Tables

TABLE 1. Measurements of specimens and selected morphological structures of Platicrista horribilis sp. nov., mounted in Hoyer’s medium.

[m] pt	[m]	pt	[m]	pt	m]	pt
Body length 720 1826,5	397	1227,9	343	1388,5	486,6	1480,97
Buccopharyngeal tube length 76 194,0	60	185,3	51	207,7	62,5	195,65
Buccal tube length 39 100,0	32	100,0	25	100,0	32,1	100,00
Pharyngeal tube length 37 94,0	28	85,3	27	107,7	30,4	95,65
Level of stylet support insertion 38 97,6 point	31	95,6	24	97,2	31,1	96,78
Buccal tube internal width 3 7,2	3	8,8	3	11,5	2,9	9,20
Semilunar structures at the end 4 10,8 of buccal tube length	4	12,5	5	21,2	4,5	14,83
1 macroplacoid length 14 36,1	8	24,3	7	27,9	9,7	29,43
2 macroplacoid length 33 84,3	18	55,9	19	76,9	23,4	72,38
Macroplacoid row length 48 121,7	29	89,7	27	109,6	34,7	107,00
Pharyngeal slender bar length 5 12,0	3	9,6	4	14,4	3,8	12,01
Pharyngeal bulb length 77 196,4	58	179,4	56	225,0	63,7	200,27
Pharyngeal bulb width 37 92,8	26	80,9	30	123,1	31,0	98,91
Primary branch of external 30 77,1 claw I length	19	58,8	13	53,8	20,9	63,26
Secondary branch of external 13 33,7 claw I length	9	26,5	10	42,3	10,8	34,17
Primary branch of internal claw 17 43,4 I length	13	41,2	11	46,2	13,9	43,57
Secondary branch of internal 10 24,1 claw I length	8	23,5	5	19,2	7,3	22,29
Primary branch of external 33 84,3 claw II length	27	82,4	21	84,6	26,9	83,77
Secondary branch of external 15 38,6 claw II length	10	29,4	10	38,5	11,4	35,48