Echiniscus madonnae, Michalczyk, Łukasz & Kaczmarek, Łukasz, 2006

Michalczyk, Łukasz & Kaczmarek, Łukasz, 2006, Revision of the Echiniscus bigranulatus group with a description of a new species Echiniscus madonnae (Tardigrada: Heterotardigrada: Echiniscidae) from South America, Zootaxa 1154, pp. 1-26 : 8-13

Echiniscus madonnae sp. nov ( Figs. 21–42 , 74 )

Description

Adult female (measurements of the holotype): body length 289.8 ( Figs. 21–24 ). Body red. Red eyes visible in living specimens only. Internal cirrus 16.2 long, external cirrus 26.1 long; internal/external cirrus ratio = 0.62. Cephalic papilla 11.4 long. Apart from head cirri and cirrus A no other appendices present. Cirrus A 61.8 long, ending in a point. Cirrus A/body ratio = 0.21. Clava 7.6 long.

Dorsal (plate) cuticle with pseudopores (hollows) and with true granulation ( Figs. 25– 30 ). Granules (true granulation, on cuticle surface) present between scapular and first paired plates, on stripes in anterior portions of paired plates, in anterior part of second median plate, and between second paired plates and terminal plate ( Figs. 35–38 ). Granules variable in size (0.5–1.5 in diameter). Cuticle appearance in SEM: pseudopores large (1.0 in diameter) and up to 1.0 deep ( Figs. 29–30 , 32 ). ‘Sponge layer’ very well developed, small pillars present ( Figs. 31–32 , 74 ). Cuticle visible in PCM: Pseudopores visible as bright, unfocusable fields; when focusing down through cuticle cuticular pillars appear as small dark focusable dots ( Figs. 25–26 ). Ventral cuticle with very fine, dense and regular granulation. This granulation is caused by dense cuticular pillars ( Figs. 33–34 ).

Plates well developed. Head and scapular plates not faceted. In LM lateral portions of scapular plate seem to be detached from the dorsal plate and form small shoulder plates (one on each side of the body) divided from the scapular plate by a thin bright stripe. This false division is caused by a bend of the plate where cuticle is thinner; in SEM this division is not visible. Third median plate absent, area between second paired plates and terminal plate covered with granules which merge in anterior portion and form a narrow ridge ( Figs. 37–38 ). Terminal plate faceted. Notches 21.9 long.

Spine on legs I in shape of narrow triangle, 4.3 long. Papilla on legs IV finger­like, 5.7 long ( Figs. 39–40 ). Dentate collar with the same sculpture as dorsal plates but pseudopores are smaller and more shallow, and with 14 sharp, triangular teeth ( Figs. 39–40 ).

Claws of legs IV 17.1 long. External claws of all legs without spurs, internal claws of all legs with a relatively large spur, directed downwards, growing out of claw at ca. 45o ( Figs. 41–42 ). Spur on claws of legs IV 3.8 long; spur/claw ratio = 0.22. Claws of legs I– III slightly shorter.

Remarks

Results of simple statistical analysis of measurements of selected morphological structures for 24 randomly chosen adult specimens are given in Table 2 and for all found juvenile specimens in Table 3 . No males, larvae and eggs were found.

The third median plate is never present in juvenile specimens, but area between the second paired plates and terminal plate is covered with granules. In most adults third median plate is also absent, however in larger specimens granules tend to merge (usually in the area close to the second paired plates and/or close to the terminal plate) and form a ridge/two ridges which could be classified as a partially developed third median plate ( Figs. 37–38 ).

Geographic distribution

Known only from the type locality.

Type depositories

Holotype and 9 paratypes are preserved at the Natural Sciences Collection, Faculty of Biology, A. Mickiewicz University, Umultowska 89, 61–614 Poznań, Poland; 20 paratypes are preserved in the collection of Ł. Michalczyk.

Etymology

We take great pleasure in dedicating this species to one of the most significant artists of our times, Madonna Louise Veronica Ritchie.

Differential diagnosis

For comparisons with other species of the bigranulatus group see Tables 7–8.

Figures

FIGURES 21 – 24. Echiniscus madonnae sp. nov. — habitus (21 – 22 holotype, 23 – 24 paratype); 21, dorso­lateral view (DIC), 22, dorso­lateral view (PCM), 23, lateral view (SEM), 24, dorsal view (SEM); 21 and 22 show the same specimen, 23 and 24 show the same specimen.

FIGURES 25 – 30. Echiniscus madonnae sp. nov. — dorsal plate cuticle; 25, surface with pseudopores (PCM), 26, pillars that appear when focusing down through the cuticle (PCM), 27, surface with pseudopores (DIC), 28, pillars that appear when focusing down through the cuticle (DIC), 29 – 30, surface with pseudopores (SEM); 27 and 28 show the same fragment of cuticle.

FIGURES 31 – 34. Echiniscus madonnae sp. nov. 31 – 32, structure of dorsal plate cuticle (SEM) (see also Fig. 74), 33 – 34, pillars of the ventral cuticle (SEM).

FIGURES 35 – 38. Echiniscus madonnae sp. nov. 35 – 36, second median plate (DIC and SEM, respectively), 37 – 38, weakly developed third median plate (DIC and SEM, respectively). Not scaled.

FIGURES 39 – 42. Echiniscus madonnae sp. nov. 39 – 40, papilla and dentate collar on the IV pair of legs (DIC and SEM, respectively), 41 – 42, claws of the IV pair of legs (DIC and SEM, respectively).

FIGURES 72 – 74. Structure of dorsal plate cuticle in three species of the bigranulatus group (semischematic section based on SEM observations); 72, E. bigranulatus (see also Figs. 11 – 12), 73, E. ollantaytamboensis (see also Figs. 53 – 54), 74, E. madonnae sp. nov. (see also Figs. 31 – 32); abbreviations: bc — body cavity, cs — cuticle surface, pi — pillar, po — pore, pp — pseudopore, sl — ‘ sponge’ layer, up — undeveloped pillar. Not scaled.

Tables

TABLE 2. Lengths [in µm] and length ratios of selected morphological structures of adults of Echiniscus madonnae sp. nov. mounted in Hoyer’s medium (MIN and MAX refer to the smallest and the largest structure found among all measured specimens; SD — Standard Deviation, N — number of specimens / structures measured).

CHARACTER	MIN	MAX	MEAN	SD	N
Body	223.3	313.5	260.2	26.7	24
Internal cirrus	10.0	20.9	15.3	2.3	24
Cephalic papilla	7.6	13.3	10.8	1.4	24
External cirrus	18.1	29.5	23.9	2.8	24
Cirrus A	42.8	83.6	65.1	10.2	20
Clava	6.2	8.6	7.7	0.8	22
Spine on leg 1	2.9	4.8	4.1	0.6	22
Papilla on leg 4	4.8	6.7	5.7	0.5	22
Number of teeth on collar	8	18	12.6	2.7	23
Notch	10.5	26.6	21.1	3.7	22
Claw IV	12.4	20.0	16.6	2.0	20
Spur of claw IV	2.9	4.8	3.8	0.6	20
Spur/Claw ratio	0.19	0.26	0.23	0.02	19
Cirrus A /Body ratio	0.19	0.31	0.25	0.03	20
Cirrus int/ext ratio	0.43	0.86	0.64	0.10	24
Cirrus int/ A ratio	0.15	0.33	0.24	0.04	20
Cirrus ext/ A ratio	0.29	0.49	0.38	0.05	20