Abstract
A new species of Acanthodasys (Gastrotricha, Macrodasyida, Thaumastodermatidae) is described from sublittoral sediments off the Atlantic coast of Florida. Acanthodasys paurocactus sp. n. is a relatively small species (to 450 µm long) with a strap-shaped outline, a series of anterior, lateral, and ventrolateral adhesive tubes, paired caudal pedicles with posterior adhesive tubes, and a morphologically diverse cuticle. The cuticle contains both spined and unspined scales. Unspined scales are present in two general shapes: lanceolate and eye shaped, with some transitional shapes. All scales have a thickened rim and depressed central region; some scales of both shapes bear either one or more central bumps, a parallel ridge, or a perpendicular ridge that gives the appearance of a cross-shaped pattern under transmitted light. Spined scales are somewhat quadrangular in shape and bear uniancres to 15 µm long with a cross-shaped sectional profile. The new species is now one of five described species to possess both spined and spineless scales, and only one of two species to possess two types of spineless scales (the second species is an incompletely described specimen from Norway).
Highlights
Gastrotrichs are microscopic invertebrates found in all oceans, seas and inland water bodies
Extraction of gastrotrichs followed a standard protocol: 1) approximately 100 cm3 of sediment was combined with 900 cm3 of 7% aqueous MgCl2 solution in a 1 L Erlenmeyer flask and allowed to rest for 10 min; 2) the flask was gently shaken and the supernatant was decanted over a 48 μm mesh; and Acanthodasys paurocactus sp. n., a new species of Thaumastodermatidae
Specimens were sorted under a Leica EZ4 stereomicroscope, transferred to a glass slide, and viewed with a compound microscope (Zeiss A1) equipped with differential interference contrast (DIC)
Summary
Gastrotrichs are microscopic invertebrates found in all oceans, seas and inland water bodies. The entire body is covered with scales and spined scales except for the hood-like region around the mouth (Fig 1, 4).
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