Minibiotus aquatilis, Claxton, 1998

Claxton, Sandra K., 1998, A revision of the genus Minibiotus (Tardigrada: Macrobiotidae) with descriptions of eleven new species from Australia, Records of the Australian Museum 50 (2), pp. 125-160 : 136-138

Minibiotus aquatilis n.sp.

Figs. 6 , 18e ; Table 5

Type material. HOLOTYPE in AM ( AM KS41452 ): Australia, Australian Capital Territory: Coppin's Crossing , 35°16'S 149°05'E, 1750 m a.s.l., 4 September 1993, S.K. Claxton . PARATYPES (7 specimens, 5 eggs in AM [ AM KS41453 - KS41462 ]; 23 specimens, 34 eggs in SKC): same data as holotype .

Additional material examined. NEW SOUTH WALES: Narrandera , 34°45'S 146°33'E, 19 March 1994, S.K. C1axton, lichen on rock in open forest, 22 specimens, 14 eggs . TASMANIA: King River, 42°00'S 145°32'E, June 1989, J. Lake, moss on rock, 3 specimens, 3 eggs. Mount Montgomery , 41°09'S 146°03'E, 21 October 1994, A. Moscal, moss on soil, 1 specimen. All SKC .

Diagnosis. Smooth cuticle with granulation on all legs; 3 long macroplacoids and a distinct microplacoid; long, slender claws with short, low accessory claws and toothed lunules on the fourth pair of claws.

Description. Body length 185-399!lm, colourless. Eye spots in the posterior position, consisting oflarge granules. Cuticle smooth, coarse granulation over back and both sides around claws on all legs. Buccal tube narrow (9% of buccal tube length). Styletsupports insertedat68.3% ofbuccal tube length, ventral reinforcing bar 53%. Pharyngeal bulb round (about 30!lID diameter), containing large granular apophyses, three macroplacoids and a microplacoid. Macroplacoid row long (37.9% of buccal tube length); first macroplacoid pear-shaped, lying close to apophysis and partly obscured by it, second macroplacoid granular, smaller than other two, third macroplacoid granular but with faint caudal knob turned towards midline. Microplacoid distinct, short and lies close to third macroplacoid. Claws long, slender (on fourth pair of legs, 34.6% of length of buccal tube) with large refractive zone at base and with short secondary branch. Accessory claws short and lie close to main branch. Lunules on first three pairs of legs smooth and distinct. Lunules on fourth pair of legs toothed.

Egg round, diameter without processes 60-70 /lID, with processes 80-93 /lm. Thirty-six processes around circumference, about 100 in hemisphere. Processes long cones tapering from hemispherical base (diameter 4-4.5 /lID) to fine tip sometimes bifurcate, often terminating in several fine hairs. Tapering portion appears to have a single row of bubbles within it. Process height 11-12.5 /lm (two eggs with processes 16-21 /lID long), about 2 /lm apart. Each process with indentations around the base. Shell

surface with large round dots around each process which may be difficult to see in some preparations.

Etymology. Latin, aquatiUs, living near water, describing the type locality.

Remarks. The population from Narrandera differs from the type only by having more prominent eyes and shorter claws (relative to the length of the buccal tube). Eggs of the Narrandera population differ by having shorter, thinner processes than the type (8-9 f1l1l long with base diameter 3-3.5 f1l1l) and a little further apart (3 f1l1l). However this is variable, one egg had process height 9-10 /lm, base diameter 2-2.5 /lm; two eggs had process height 5-7 f1l1l, base diameter 3 /lm. The dots around the processes are particularly clear in eggs from King River.

The species is similar to Minibiotus maculartus Pilato & Claxton, 1988 and Minibiotusj10riparus n.sp., having a smooth cuticle and granulation around all claws but differs from them in the position of insertion of the stylet supports and by having longer macroplacoids as well as having different shaped egg processes.

Habitat. The species was found in short turf moss and foliose lichens on rocks close to the Molonglo River at the type locality. At Narrandera it was found in very dry foliose lichens on rock in an open woodland and at King River in fine moss on rock.

Figures

Figure 6. Taxonomic details of Minibiotus aquatilis n.sp. a, habitus (holotype); b, egg; c, ventral view of the buccal armature; d, claws of the first pair of legs; e, claws of the fourth pair of legs; f, detail of eggshell.

Figure 18. Eggs of a, Minibiotus intermedius DIC; b, Minibiotus taiti DIC; c, Minibiotus poricinctus Phase; d, Minibiotus Jloriparus Phase; e, Minibiotus aquatilis Phase; f, Minibiotus hispidus DIe. (Scale bars = 10 J..Illl).