Bryodelphax parvulus Thulin, 1928

Pilato, Giovanni, Lisi, Oscar & Binda, Maria Grazia, 2010, Tardigrades of Israel with description of four new species, Zootaxa 2665, pp. 1-28 : 6

Bryodelphax parvulus Thulin, 1928

Material examined. Locality No. 19: Mt. Meron : near Har Bar-Yohai (only one specimen) .

There is confusion about the sense organs on legs of this species. According to Cuénot (1932), B. parvulus has a spine on the first pair of legs and a papilla on the hind legs ( Kristensen (1987) indicated the presence of sense organs on legs I and IV as a character of the genus), but according to other authors (e.g. Marcus, 1936; Morgan & King, 1976; Ramazzotti & Maucci, 1983; Maucci, 1986) in B. parvulus these structures may be present or absent. Many authors recorded this species but did not specify whether these structures were present or absent in their specimens. In the past we have attributed to the species B. parvulus many specimens from Italy, Northern Africa, Poland and Russia, all lacking spine I and papilla IV. Thulin (1928) instituted the species B. parvulus for the Canadian form of Echiniscus intermedius described by Murray (1910, page 161) (the Type form of Echiniscus intermedius , was described from Australia ( Murray, 1910, page 129) and is today ascribed to the genus Bryochoerus ). We ascertained that Murray, in describing the Canadian form, did not specify whether a spine on legs I and a papilla on legs IV were present or not. Interestingly, Murray (1910) did not draw the papilla for the Canadian form (see: Figures 52a and 52b; Tav. XX), while in the figure 17 (Tav. XVI), relating to the Type (Australian) form of Echiniscus intermedius , the papilla IV is clearly visible. We have many doubts about the attribution of the presence or absence of these structures to ‘individual variability’, and we can hypothesize that the presence of a spine on legs I and of a papilla on legs IV in Bryodelphax parvulus derived from the description of the Type form of Echiniscus intermedius . We also think that if specimens with spine I and papilla IV truly exist, they have to be ascribed to another species, not B. parvulus ; besides, it is possible that specimens lacking those structures have already been ascribed to different species.

With regard to the lateral intersegmental platelets, Murray (1910) did not specify whether they were or were not present. All the specimens we have examined have 12 platelets and we think that the presence of these structures may have passed unnoticed by other taxonomists due the difficulty in observing these characters.

The specimen from Israel has lateral intersegmental platelets, lacks spine I and papilla IV, and is similar to European specimens in the cuticular ornamentation. In conclusion, we feel justified in attributing the Israeli specimen to B. parvulus .

The species, a new record for Israel, has been recorded for all the zoogeographic regions, excluding Australian and the Antarctic.