Echiniscus zetotrymus Horning, Schuster & Grigarick, 1978

Pilato, Giovanni, Binda, Maria Grazia & Lisi, Oscar, 2005, Remarks on some Echiniscidae (Heterotardigrada) from New Zealand with the description of two new species, Zootaxa 1027 (1), pp. 27-45 : 27-45

Echiniscus zetotrymus Horning, Schuster & Grigarick, 1978 ( Fig. 4 )

Material examined: South Island , Jollybrook River, Lake Sumner area, two paratypes from a lichen sample ( Usnea ciliata ) .

The description of E. zetotrymus needs some specifications. About the plate sculpture Horning et al. (1978) wrote: “Dorsal plates with a random pattern of pores generally less than 1 m diameter (fig. 28)”. This figure shows few scattered pores and gives the impression of pores very widely spaced from one another; this probably induced Ramazzotti & Maucci (1983) to write (p. 488): “pori irregolarmente distribuiti e piuttosto distanziati”. We noted ( Fig. 4 A, B ) that the pores are numerous and not very spaced, and we also noted that they are randomly scattered on the head and scapular plates, on the median plate 1, on the anterior portion of the median plate 2, on the median plate 3 and on the anterior portions of the paired plates II and III; while on the posterior portion of the above mentioned paired plates II and III and on the terminal plate, the pores tend to be arranged around well defined circular areas ( Fig. 4 B ). Small sculptured areas are present laterally to the scapular plate ( Fig. 4 A ) and, less evident, laterally to the median plates 1 and 2. The paired plates II and III have a transversal smooth band, and the anterior portion subdivided into two portions by an oblique smooth band. The ventral surface has extremely fine dots which are very difficult to see. First pair of legs with an acuminate spine ( Fig. 4 A ); hind legs with papilla and dentate fringe. Each internal claw with a spur.

There is confusion in the description of the lateral and dorsal appendages of the species. Horning et al. (1978) wrote: “long lateral spines present at B, C and E”, but they also wrote: “This is the only Echiniscus with long filaments, both dorsal and lateral, but with no spines on plate D”. In the cited figure 28 ( Horning et al. 1978, p. 201) all lateral and dorsal appendages are filaments. In the paratypes we examined, we noted the presence of filaments A, spines (not filaments) C and D and long filaments E; appendages B are absent. Dorsal appendages are long spines Cd (in the specimen of fig. 4 one of the appendages, Cd, is broken).

Considering the different plate sculpture, the absence of spine B and the presence of spine D in the examined paratype, we cannot establish whether the examined specimen does not belong to E. zetotrymus or whether this species is more variable than Horning et al. (1978) described.

Figures

FIGURE 4. Echiniscus zetotrymus (paratype): A, B, details of the plate. Scale bar = 10 m.