Echiniscus azoricus, Fontoura, Paulo, Pilato, Giovanni & Lisi, Oscar, 2008

Fontoura, Paulo, Pilato, Giovanni & Lisi, Oscar, 2008, Echiniscidae (Tardigrada, Heterotardigrada) from Faial and Pico Islands, the Azores, with the description of two new species, Zootaxa 1693, pp. 49-61: 50-54

publication ID

http://doi.org/ 10.5281/zenodo.180650

persistent identifier

http://treatment.plazi.org/id/F6611419-CE21-FF49-EBD4-10D3FCC7FB64

treatment provided by

Plazi

scientific name

Echiniscus azoricus
status

sp. nov.

Echiniscus azoricus   sp. nov.

Fig. 1 View FIGURE 1 A –E, Tables 1 & 2

Material examined: Holotype (female) and six paratypes (4 females and 2 specimens of unknown sex) from a moss sample collected in Terras do Pico, Pico Island. All the specimens were mounted in Hoyer’s medium with a small amount of potassium iodide.

Type repository: The holotype (slide N. 5200) is preserved at the Museum of the Dipartimento di Biologia Animale “Marcello La Greca”, Università di Catania in the collection of Binda & Pilato. The six paratypes (BII- 6 to BII- 11) are preserved in the collection of P. Fontoura at the Department of Zoology and Anthropology, Faculty of Sciences, University of Porto.

Specific diagnosis: Small Echiniscus   with unpaired plate 3 present; dorsal plates sculptured with dark knobs surrounded by a ring of small pores. Anterior portion of the median plate 2, anterior portion of paired plates II and III, and median plate 3 with very few or no pores. Apart from the cirrus A, all lateral appendages (B, C, D, E) and dorsal appendages present (C d and D d) are spines.

Description of the holotype: Adult female. Body length about 180 µm. Eyes absent in living specimens. Body reddish-brown. Median plate 3 present.

The dorsal plates’ sculpture consists of large dark knobs surrounded by a ring of small pores, generally six or seven pores ( Fig. 1 View FIGURE 1 A –D). Cephalic plate with knobs and pores ( Fig. 1 View FIGURE 1 A & B), notch on cephalic plate not visible due to the unsuitable orientation of the holotype (the notch is visible on paratype BII- 8). Neck plate ( Fig. 1 View FIGURE 1 A & B) thin and sculptured with small knobs (about 1.2 µm in diameter) and few pores (about 0.7 µm in diameter). Scapular plate unfaceted, without smooth transversal or longitudinal bands but with two lateral folds forming two small shoulder plates. The sculpture of the shoulder plates consists only of small knobs (about 1.2 µm in diameter), pores are lacking. Large knobs (2.7 µm in diameter) and pores (1.7 µm in diameter) are present in the central portion of the scapular plate ( Fig. 1 View FIGURE 1 A & B). Paired plates II and III divided into an anterior and a posterior portion by a single and thin transversal band without sculpture ( Fig. 1 View FIGURE 1 D). Posterior portion of the paired plates with large dark knobs (diameter 2.7 µm) surrounded by pores (diameter about 1.0 µm); the diameter of these knobs decreases gradually laterally and anteriorly ( Fig. 1 View FIGURE 1 B & D). In the anterior portions of the paired plates the knobs are also smaller (about 1.4 µm in diameter) and the pores are very scarce ( Fig. 1 View FIGURE 1 B & D). Median plates 1, 2 and 3 present ( Fig. 1 View FIGURE 1 A, C & D). Median plates 1 and 3 undivided with the same pattern of ornamentation as the scapular plate with knobs (diameter 2.0 µm) and pores (diameter 1.2 µm). Median plate 2 with a thin transversal and smooth band ( Fig. 1 View FIGURE 1 D); the posterior portion of this plate has knobs larger than those of the anterior portion (respectively 2.4 and 1.4 µm in diameter) and also larger and more numerous pores (respectively 1.2 and 0.8 µm in diameter). Intersegmental areas ornamented only with small dark knobs with a diameter of about 0.7 µm. Terminal plate unfaceted (but gently faceted in some paratypes), with the two usual postero-lateral indentations (19.5 µm long) and with the same pattern of sculpture as the scapular plate with large knobs (about 3.2 µm diameter) and pores (1.6 µm in diameter) ( Fig. 1 View FIGURE 1 C). No smooth longitudinal or transversal band on terminal plate is present. The ventral cuticle has a very fine granulation.

Leg plates with fine granulation except on leg IV where they present a sculpture with very small knobs and some small pores. A spine (2.4 µm long) is present on legs I; hind legs with a papilla (3.9 µm long) and a dentate fringe with about 13 sharp, triangular teeth 2.6 µm long ( Fig. 1 View FIGURE 1 E).

Cephalic cirri with cirrophore; internal cirrus 10.6 µm long; external cirrus 16.2 µm long; cephalic papilla 7.0 µm long; clava 5.4 µm long ( Fig. 1 View FIGURE 1 A,B). Apart from cirrus A (filament 52.6 µm long), all other lateral and dorsal appendages are spines: spine B, 16.9 µm long; C, 22.0 µm long; D, 20.6 µm long and E, 13.7 µm long. Dorsal appendages C d and D d are short spines: C d, 2.4 µm long and D d, 2.3 µm long.

External claws smooth, internal claws of all legs with a straight and thin spur directed downwards. Internal claws of legs IV 12.9 µm long with a spur 3.3 µm long inserted at about 3.7 µm from base (28.7 %) ( Fig. 1 View FIGURE 1 E). External and internal claws IV 11.5 µm and 12.9 µm long respectively; claws I –III slightly shorter ( Table 1).

In Table 1 the measurements of the smallest and the largest (the holotype) specimens are recorded.

Eggs unknown.

Variability: The combination of lateral and dorsal spines was similar in all the seven specimens examined and, besides some differences in length ( Table 2), no asymmetry has been found. Spine C is the longest, followed by D. The length of spine E, in contrast with B, is very variable ( Table 2). The dorsal appendages can be very short spines less than 3 µm long as in the holotype, or relatively long spines (about 15 µm in BII- 7 and BII- 11, cf. Table 2).

Etymology: The name azoricus   refers to the Archipelago of the Azores that includes the Island of Pico, the locus typicus of the new species; azoricus   = from the Azores.

Differential diagnosis: Taking into consideration the pattern of the cuticle ornamentation, the lateral and dorsal appendages present and the characters of these appendages, Echiniscus azoricus   sp. nov. appears different from all the known species of the genus. A few species have a pattern of cuticular ornamentation somewhat similar to that of Echinicus azoricus   sp. nov.: E. bisculptus Maucci, 1983   , E. vinculus   , E. ehrenbergi   , E. curiosus   , E. zetotrymus   (according to Pilato et al., 2005) and E. laterospinosus Rudescu, 1964   , but the new species differs from them.

It differs from E. bisculptus   in having lateral appendages A, B, C, D, E and dorsal appendages C d and D d while in E. bisculptus   the filament A is the only appendage present.

E. azoricus   sp. nov. differs from E. vinculus   in having lateral appendages A, B, C, D and E and dorsal appendages C d and D d while in E. vinculus   only the appendage A is present. In addition, E. vinculus   has very evident smooth areas on the scapular and the terminal plates absent in E. azoricus   sp. nov.

The new species differ from E. curiosus   and E. zetotrymus   in having cuticular dark knobs less dense; this is particularly evident on the scapular plate, where the pores are larger and forming a ring around each dark knob ( Figs. 1 View FIGURE 1 A, B & D; 2 A & B). The smooth transversal band on the paired plates II and III is less evident than in E. curiosus   and E. zetotrymus   ( Figs. 1 View FIGURE 1 D, 2 A, B & C); in addition, in these species the anterior portion of the median plate 2 is sculptured only on its anterior margin ( Figs. 2 A & C View FIGURE 2. A, E ), and the appendage B is lacking.

E. azoricus   sp. nov. differs from E. eherenbergi   in having more scattered dark knobs, larger and more numerous pores. In E. ehrenbergi   the knobs are often contiguous or fused to one another, and the pores, very small, do not form a true ring around each knob. In addition, in this species the lateral appendages are filaments and the dorsal appendage C d is lacking.

E. laterospinosus   is a nomen inquirendum believed to be composed of two different species ( Ramazzotti & Maucci, 1983). E. azoricus   sp. nov. differs from it in the presence of the median plate 3 and in having lateral and dorsal appendages with a normal base not enlarged.

TABLE 1. Measurements (in µm) of some structures of the smallest and the largest (the holotype) specimens of E. azoricus sp. nov. (% bo = percentage of body length; % sc = percentage of scapular plate length).

External cephalic cirrus        
    146.1   133.2

TABLE 2. Measurements (in µm) of the lateral and dorsal appendages of the examined specimens of E. azoricus sp. nov. (Htype = holotype; BII- 6 – BII- 11 = paratypes).

  Htype BII-6 BII-7 BII-8 BII-9 BII-10 BII-11
Dorsal appendage D d