Austeruseus rokuri

Trygvadóttir, Birna Vár & Kristensen, Reinhardt Møbjerg, 2011, Eohypsibiidae (Eutardigrada, Tardigrada) from the Faroe Islands with the description of a new genus containing three new species, Zootaxa 2886, pp. 39-62 : 55-57

Austeruseus rokuri nov. sp.

( Figures 16–18 )

Type material. the holotype (slide FO2-009 [ZMUC-TAR-1080]) and 5 paratypes (slides FO2-010 to FO2-014 [ZMUC-TAR-1081 to ZMUC-TAR-1085]). The slides are deposited in the Zoological Museum, the Natural History Museum of Denmark, The Zoological Museum, Invertebrate Dept., University of Copenhagen, Copenhagen, Denmark.

Type locality. Sornfelli mountain, Streymoy, Faroe Islands ( Fig. 1 C). Temporary puddle. GPS: 62°04.445’N, 6°57.252’W. Altitude 600 m a.s.l. Date: 26 October 1989. Coll.: Reinhardt M. Kristensen.

Additional material. one specimen in moult (slide FO20C-012 [ZMUC-TAR-1086]) was found in Varmakelda, Eysturoy, Faroe Islands. Homothermic spring. GPS: 62°13.097’N, 6°46.721’W. Altitude 15 m a.s.l. Date: 26 October 1989. Coll.: Reinhardt M. Kristensen.

Etymology. A. rokuri is named after BVT’s youngest son Rókur.

Specific diagnosis. Large sized animal with two macroplacoids (the first broken in the middle) and large microplacoid. Eyes present. Ventral strengthening bar, absent. Up to 6 lateral hook-shaped appendages for the insertion of stylet muscles. Three rows of teeth in the buccal cavity. Large claws of Eohypsibiidae type.

Description. Holotype (adult female) ( Fig. 16 ): Body length, 564.1 µm (body length for paratypes, 329.4– 646.0 µm). Eyes present. Cuticle with many small dots (not “pearls”) scattered over the whole body (dorsal and ventral surfaces), but more dense at the caudal end. Mouth opening with 14 peribuccal lamellae. Buccal tube rigid, 46.4 µm long and 6.7 µm wide. Ventral strengthening bar absent. Buccal tube with three sets of wing- or hookshaped appendages (positioned dorso- and ventro-laterally) for attachment of the stylet muscles. Stylet supports inserted on the buccal tube at 35.6 µm. Furca large, not in contact with the pharyngeal bulb. Three bands of teeth present in the buccal cavity. First band of infrabuccal teeth, right behind the peribuccal lamellae and comprised of a broad band of asymmetrical arranged small teeth (mucrones) in>5 rows. Second band of infrabuccal teeth, immediately behind the first comprised of a single row of larger teeth. Third band of infrabuccal teeth, behind the second row, comprised of four teeth (infrabuccal baffles). Pharyngeal bulb oval with large triangular apophyses, and three cuticular rods close to the apophyses ( Figs. 17 A & 18B, arrows). These rods are also present in Bertolanius and Eohypsibius , and other genera, e.g. Macrobiotus and Isohypsibius (R. Bertolani, pers. comm.). Two macroplacoids, the first, 14.4 µm long and broken in the middle, the second, 7.7 µm long, and a large microplacoid, shaped as a bent rectangle, 5.4 µm long.

Claws Eohypsibiidae type, very large. Smooth lunules present on all claws. The external claws larger than the internal, with largest on the fourth pair of legs. Two robust accessory points on primary branches ( Figs. 17 B–C & 19C). Cuticular bars on all legs, absent. Eggs unknown.

Figures

FIGURE 16. Austeruseus rokuri, nov. gen. et nov. sp., holotype (female), habitus in ventral view (scale bar 100 μm). Abbreviations: b: brain, c: cloaca, e: eyespot, o: ovary, p: pharynx, mg: midgut, mt: malphigian tubules. Drawing by Stine Elle.

FIGURE 17. Austeruseus rokuri, nov. gen. et nov. sp. (scale bars 10 μm). A: ventral view of bucco-pharyngeal apparatus. B: claws on leg I. C: claws on leg III. Abbreviations: a: apophyses, ac: accessory point, bt: buccal tube, cd: cuticular dots, h: hookshaped appendage, l: peribuccal lamellae, m 1: first macroplacoid, m 2: second macroplacoid, mi: microplacoid, r 1: first row of teeth, r 2: second row of teeth, r 3: third row of teeth, ss: stylet sheath, su: stylet support. Drawings by Stine Elle.

FIGURE 18. Austeruseus rokuri, nov. gen. et nov. sp., holotype (LM). A: habitus (scale bar 200 µm). B: ventral view of buccal tube, arrows: cuticular rods in pharynx. C: Eohypsibiidae-type claws on leg III, note also the granulation of the cuticula. D: claws on leg I. E: bucco-pharyngeal apparatus, ventral view (B – E scale bars 10 µm).

FIGURE 1. A: Map overview of the Faroe Islands with the sampled stations (black triangles). B: Vaðhorn, to the right, type locality of Austeruseus faeroensis, nov. sp. and type species for the new genus (photo courtesy: KT Depilin). C: Sornfelli mountain on Streymoy, type locality of Austeruseus rokuri nov. sp. (white squares indicate the sample sites) (photo courtesy: the Faroese Earth & Energy Directorate).