Echiniscus arthuri, Pilato & Binda & Lisi, 2005

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 arthuri sp. nov. ( Figs. 2 , 3 A, B )

Material examined: South Island : Arthurs Pass National Park, Upper Otira Valley, one specimen from a sample of Racomitrium ptychophyllum (mosses) on rock scree .

Unfortunately the quality of the photos is not optimal due to the quality of the specimen.

Horning et al. (1978) attributed to Echiniscus velaminis Murray, 1910 this specimen that, in our opinion, belongs to the new species described here.

Description of the holotype: Body length 285 µm; eyes absent according to Horning et al. (1978). Median plate 3 present ( Fig. 2 B , 3 A ); ventral plates absent. All dorsal plates with almost invisible small dots and pores of various shape and size ( merokensis type). Head plate with anterior notch; neck plate narrow ( Fig. 2 A ); scapular plate without smooth transversal bands; as in many species of Echiniscus , it is composed of three pieces, i.e., a larger central one and two smaller lateral pieces ( Fig. 2 A ); each paired plate II and III with smooth transversal band ( Fig. 2 B ); terminal plate with two postero­lateral incisions, without smooth areas ( Fig. 3A ). Ventral surface with very fine, almost invisible dots.

Lateral spines C and D, filaments E, dorsal filaments Cd and spines Dd are present in addition to the filaments A. An evident spine is present on the first pair of legs; a papilla and a fringe with obtuse teeth on the fourth pair of legs. The length of some structures is indicated in Table 1. External claws without spurs, each internal claw with an obvious spur ( Fig. 3 B ).

Etymology: The name arthuri derives from the locality where the holotype was found: Arthurs Pass National Park

Remarks: Echiniscus arthuri sp. nov. differs from Echiniscus velaminis in having the sculpture of the terminal plate not very different from that of the other plates; it has smooth bands on paired plates II and III while Murray (1910, p. 112) specified that “None of the plates has the surface markings interrupted by lines or bands”; it also differs from E. velaminis in having well­developed spurs on the internal claws; Murray specified “claws all without barbs”; he was an excellent observer and it is not believable that he would not have noted such well­developed spurs if they had been present.

The new species differs from E. clevelandi Beasley, 1999 in the following features: fine plate dots almost invisible, appendage B absent, the appendages E and Cd are filaments.

Echiniscus arthuri sp. nov. differs from E. carusoi Pilato, 1972 in having pores more various in shape and size, in having a filament (not a spine) E. In addition, it is to be noted that E. carusoi only exceptionally has lateral spines C and D, and that the combination of filaments A, C, D, E, Cd and Dd has never been found in this species.

The new species differs from E. curiosus Claxton, 1996 in having the cuticular pores not regularly arranged around central dark areas of definite shape; in addition, the appendages E and Cd (often absent in E. curiosus ) are filaments.

E. arthuri sp. nov. differs from E. testudo ( Doyère, 1840) in details of the plate sculpture; in the presence of dorsal appendage Cd; in having shorter claws, and internal claws with more developed spurs.

It differs from E. lichenorum Maucci, 1983 in lacking smooth bands on the scapular and terminal plates, in the presence of the appendage E, and in having more developed spurs on the internal claws.

The new species differs from E. bartramiae Iharos, 1936 in details of the plate sculpture (pores various in shape in E. arthuri sp. nov., regular granulation in E. bartramiae ), and in having appendages C and D shorter (spines instead of filaments). Iharos (1936) did not specify whether smooth bands are present on some plates, and he did not specify whether spurs are present on the internal claws or not.

E. arthuri sp. nov. is similar to E. merokensis Richters, 1904a , but we examined specimens of this species from many localities ( Italy, North Africa, Ecuador, Tierra del Fuego) and have noted some constant differences between the species here compared. In E. arthuri sp. nov. the plate sculpture is of the same type (pores) on all plates while in E. merokensis , on the anterior portion of the paired plates II and III and on the anterior portion of the median plate 2, very few or no pores are present ( Fig. 3 C ); in E. arthuri sp. nov. no smooth band is present on the scapular and terminal plates.

Figures

FIGURE 2. Echiniscus arthuri sp. nov. (holotype): A, B, details of the plate sculpture. Scale bar = 10 m.

FIGURE 3. A, B: Echiniscus arthuri sp. nov. (holotype): A, details of the plate sculpture; B, claws of the first three pairs of legs. C: Echiniscus merokensis, details of the plate sculpture. Scale bar = 10 m.