Milnesium tardigradum Doyère 1840

Guil, Noemí, 2008, New records and within-species variability of Iberian tardigrades (Tardigrada), with comments on the species from the Echiniscus blumi-canadensis series, Zootaxa 1757, pp. 1-30 : 15

Milnesium tardigradum Doyère 1840

I have analyzed 664 specimens found in LF, MR, LR, MT and LT samples. The presence of more massive and shorter claws, basal spurs on the outer claws, and accessory points in all claws distinguish this species ( Tumanov 2006). I have observed variation in presence or absence of the basal spur on the outer claws. I have observed three specimens which present a basal spurs on the outer claws of some legs, but not on other legs. Within the same population, I have found specimens with basal spurs on their outer claws of all legs mixed with specimens with basal spur on the outer claws of some legs but not on others. I also observed several specimens of Milnesium tardigradum with shorter buccal tubes when comparing individuals of similar sizes; however, the remaining morphological characteristics were the same in all of them. A total of 70% of specimens present ocular spots; in the remaining 30% it was not possible to determine their presence or absence. Mastax from rotifers (Belloidea), tardigrades (probably from Macrobiotidae and Ramazzottius ), and diptera larvae (up to 10 larvae) have been observed inside some specimens. Body size was 385 to 1957 μm, mean 933 μm (SD 263). The species is considered cosmopolitan ( McInnes 1994). In the Iberian Peninsula, it has been recorded for Portugal ( Da Cunha 1941; Fontoura 1981, 1982; Maucci & Durante Pasa 1984, 1985) Spain ( Heinis 1908; Rodríguez Roda 1947a, b, 1949, 1952; Mihelčič 1954; Lewin Osorio 1984) and Gibraltar ( Rodríguez Roda 1952). Milnesium tardigradum was found at 54 sampling points (Table 3).