Batillipes potiguarensis, Santos, Erika, Da Rocha, Clélia M. C., Jr, Edivaldo Gomes & Fontoura, Paulo, 2017

Santos, Erika, Da Rocha, Clélia M. C., Jr, Edivaldo Gomes & Fontoura, Paulo, 2017, Three new Batillipes species (Arthrotardigrada: Batillipedidae) from the Brazilian coast, Zootaxa 4243 (3), pp. 483-502 : 496-499

Batillipes potiguarensis sp. nov.

( Fig. 6 ; Table 3 )

Diagnosis. Medium sized Batillipes with tubular undivided primary clavae and well developed papillar secondary clavae. Cephalic cirri with swollen distal tips. Sensorial spines on all legs. Sensorial organ on leg IV very short. Legs terminated by long toes with spatula-like suction discs. Toes 3 and 4 of legs IV of equal lengths (pattern of the A group of species proposed by Kristensen and Mackness, 2000). Distinct head separated from the body by a neck constriction. Scapular region well developed, protruding laterally at the level of the first pair of legs. Small lateral blunt processes between legs I–III. Well-developed blunt processes between legs III and IV. Prominent semicircular caudal projection. Cuticle finely punctated with transverse folds. Rosette-like female gonopore delimited by four punctate cuticular platelets.

Type locality. Amor Beach , Rio Grande do Norte, Brazil, (6°13'41"S, 35°02'29"W).

Type material. Holotype: adult, female (slide CVII-82) collected at Amor beach, mounted in glycerol. Paratypes mounted in glycerol: one female collected at Gunga beach (slide TARD/UFRPE 02-23); and 3 females collected at Amor beach (slides TARD/UFRPE 02-24 and CVII-82); 1 female and 1 juvenile collected at Francês Beach (slides TARD/UFRPE 02-25 and 02-26).

Type repository. The type material (slide CVII-82) is deposited in the collection of the Department of Biology, Faculty of Sciences , University of Porto , Portugal, and the other slides in the collection of Tardigrades— UFRPE ( Laboratory of Meiofauna , Department of Biology , Universidade Federal Rural de Pernambuco, Brazil) .

Etymology. The name potiguarensis refers the inhabitants of the State of Rio Grande do Norte where the new species was found, primitively named the Potiguar Territory.

Ecological note. B. potiguarensis sp. nov. was found in shallow sublittoral medium to coarse gravels and quartz sands, in reef pools of high energy beaches (Amor Beach) and low energy beaches (Francês Beach).

FEMALES JUVENILE adults 6-toed

STRUCTURES Holotype Mean ± SD (Range); N

Description of the holotype. Female, 171 µm long (187 µm including the caudal apparatus) and 62.1 µm wide between the third and fourth pair of legs ( Figs 6 A, B). Typical trapezoid head separated from the body by an evident neck constriction. Head bearing eleven cephalic appendages. Internal cirri inserted dorsally on the frontal edge of the head are 21.8 µm long with cirrophores (about 3.8 µm long). External cirri 20.1 µm long, with indistinct cirrophores, inserted more ventrally, near the lateral cirri and primary clavae. The median cirrus, with cirrophore (2.6 µm), is 20.5 µm long. The lateral cirrus, 35.8 µm long, is located dorsally in relation to the unconstricted, but wrinkled, tubular primary clava, 19.4 µm long ( Fig 6 C). These two appendages share a common pedestal. A van der Land’s organ is present inside the base of the primary clava that has a terminal pore. Well developed and prominent papillar secondary clavae (diameter about 5.6 µm) are visible on the frontal edge of the head ( Fig 6 C). All the cephalic cirri, including the external cirri and the lateral cirri have a optically dense dot (black dot when observed under PHC) near their swollen tips. There is no notch between internal and external cirrus nor an indentation between the external cephalic cirrus and the pedestal bearing the primary clava and lateral cirrus. Eye spots not observed. The ovoid pharyngeal bulb is 21.3 µm long and 20.7 µm wide. Placoids not visible after slide mounting.

A lateral blunt expansion (auricle), 6.8 µm long, is present between the head and the first pair of legs ( Fig 6 C). The scapular region is well developed (70.8 µm wide) protruding laterally at the level of the first pair of legs ( Fig. 6 A, B). At the level of the second pair of legs a weak body protrusion is also visible. Ventrolateral blunt processes ( Fig. 6 A, B) are present between all leg pairs, particularly developed between legs III and IV (4.6, 5.8 and 9.1 µm between legs I–II, II–III and III–IV respectively). The caudal region has a conspicuous semicircle-shaped protrusion, 15.2 µm long.

Sharply pointed (20.1 µm long) cirri E with small cirrophores. Sensorial organs present on all legs (9.8; 11.4; 10.8, and 6.6 on leg I, II, III and IV respectively). Leg sense organs of legs I and IV divided into a basal and a distal portion with a dot near their swollen tips. The short sense organ on leg IV ( Fig 6 A, B) has a van der Land’s organ separating the two portions (basal portion 3.1 µm long; distal portion 3.5 µm long). Sense organs on legs II and III are spines.

Telescopic legs with long toes. Toes with the distal stalk with a distal enlargement (3.0 µm wide), spatula-like suction discs (5.3 µm long and 4.7 µm wide on leg IV) with straight frontal edge, short and thin braces and slightly thickened lateral edges. In the first three pair of legs, toe 2 is the shortest, toes 3 and 5 are the longest and toes 1, 4 and 6 are medium sized (in leg I 10.3, 7.9, 19.7, 11.4, 20.6 and 12.4 µm long for toes 1 to 6 respectively). In the fourth pair of legs ( Fig. 6 D) the toes conform to the pattern of the A group of species proposed by Kristensen and Mackness (2000), with medial toes 3 and 4 of equal lengths (15.5 and 15.7 µm long respectively). Toes 5 and 6 of legs IV are respectively 25.7 and 19.1 µm long and toes 1 and 2 were not measurable (in paratypes toes 2 and 5 are the longest and similar each other; toes 1 and 6, also similar each other, are of intermediate length).

Dorsal cuticle punctated (about 12 pillars/10 µm; each pillar with about 1 µm high) with about eight transverse folds. Ventral transverse folds are also visible.

Rosette-like gonopore delimited by four punctate cuticular platelets, two anterior and two posterior forming a groove in direction to the anus ( Fig. 6 E). The anus is 10.8 µm distant from the gonopore.

Remarks. Males and four-toed larvae were not found. Morphometric variations in lateral processes and caudal projection of adult specimens were not observed. The only juvenile observed, with six toes on each leg but without a visible gonopore, is similar to adult females also.

Differential diagnosis. Batillipes potiguarensis sp. nov. in having toes 3 and 4 of the hind legs of equal lengths and respectively different from toe 1 and toe 2, belongs to the A group of species ( Kristensen and Mackness 2000). There are 20 known species included in this group. However, similarly to the new species, only two species, both with limited geographic distribution in the Pacific Ocean, have simultaneously a blunt or semicircular caudal protrusion and blunt lateral processes between legs III and IV: B. rotundiculus Rho, Min and Chang, 1999 , described from the Korean coasts (Sea of Japan) and B. solitarius Jørgensen, Boesgaard, Møbjerg and Kristensen, 2014 , from the Australian coast (Tasman Sea).

B. potiguarensis sp. nov. differs from B. solitarius in having a much more protruded semicircular caudal projection; smaller and different shaped secondary clavae (prominent papilla, less than 6.2 µm wide in the new species, concave and elongate lens-shaped, 13.0 µm wide, in B. solitarius ) and lateral projection between legs I and II (blunt in the new species; sharp pointed in B. solitarius ). Moreover, cephalic cirri in B. potiguarensis sp. nov. have a plain tip, while in B. solitarius median, internal and lateral cirri have terminal tufts.

The new species is very similar to B. rotundiculus . These two species share a similar caudal protrusion, a welldeveloped scapular region at the level of the first pair of legs, and similar blunt-shaped ventrolateral processes. However Batillipes potiguarensis sp. nov. can be distinguished from B. rotundiculus in having swollen cephalic cirri (sharply pointed in B. rotundiculus ) and an evident and protruded secondary clavae (not present in B. rotundiculus ). In addition, the two species also differ in the relative length of leg sense organs: contrary to B. rotundiculus , in the new species sense organs on leg IV are particularly shorter and shorter than sense organs on leg I (in the holotype of B. rotundiculus leg spine I is 8 µm and sense organ on leg IV is 9.2 µm; in B. potiguarensis sp. nov. leg spine I is 9.8 µm and sense organ IV is 6.6 µm, specimens respectively 195 and 187 µm long, including caudal apparatus). Moreover, the leg IV sensory organs of B. rotundiculus are spike-shaped while in the new species they are divided into two portions, the distal portion with swollen tips. Another important differentiating character between the two species is the relative size of medial (toes 3 and 4) and lateral toes (1 and 6) on legs IV. In B. potiguarensis sp. nov. toes 3 and 4 of hind legs are shorter than toes 1 and 6 while in B. rotundiculus they are similar or longer (in the holotype lateral toes are 16.6 and 17.1 µm long and medial toes are 17.5 and 17.1 µm long).

Figures

FIGURE 6. Batillipes potiguarensis sp. nov. A. Drawing (dorsal view); B. Habitus (dorsal view of a paratype); C. Detail of clavae (pc—primary clava; sc—secondary clava), first body projection (pr 1) and leg spine of the first leg (pI) of the holotype; D. Toes (t 1 – t 6) of the leg IV of a paratype; E—Gonopore (go) and anus (an) of the holotypic female. Scale bars: A – B = 50 µm; C – E = 10 µm.

Tables

TABLE 3. Measurements (in µm) of selected morphological structures of specimens of Batillipes potiguarensis sp. nov. (Holo—Holotype; SD—Standard deviation; Range refers to the smallest and largest measured specimen / structure; Nnumber of specimens / structures measured).

Body length (BL) BL without caudal apparatus Body width	187 171 62.1	184.5 ±18.04 (152.2–201.1); 6 168.8 ±21.55 (129.3–191.5); 6 64.5 ±11.26 (47.9–78.1); 6	183 175?
Scapular region width Median cirrus Internal cirri	70.8 20.5 21.8	69.1 ±7.54 (58.0–80.2); 6 16.0 ±4.20 (10.4–20.5); 4 20.5 ±1.93 (17.0–22.5); 6	49.7 17.2 18.0
External cirri Lateral cirri A Primary clavae	20.1 35.8 19.4	16.0 ±3.26 (12.6–20.1); 5 28.8 ±4.27 (22.7–35.8); 6 16.5 ±2.26 (13.4–19.4); 6	14.6 24.7 12.8
Primary clava / cirrus A Secondary clavae Cirri E	0.54 5.6 20.1	0.58 ±0.10 (0.47–0.75); 6 5.1 ±1.05 (3.7–6.2); 5 20.3 ±2.27 (17.0–22.8); 5	0.52 6.2?
Leg I spine Leg II spine Leg III spine	9.8 11.4 10.8	10.0 ±0.93 (8.3–10.9); 6 9.8 ±2.51 (7.3–13.5); 5 10.6 ±2.64 (7.2–13.1); 4	? 15.2 10.6
Leg IV organ Leg IV base Leg IV spine	6.6 3.1 3.5	8.4 ±1.9 (6.6–11.1); 6 3.6 ±0.92 (3.0–5.4); 5 4.2 ±0.79 (3.5–5.4); 5	6.5??
Body projection 1 Body projection 2 Body projection 3	6.8 4.6 5.8	6.0 ±1.62 (3.2–7.8); 6 4.4 ±1.47 (2.5–6.1); 4 5.5 ±1.30 (3.8–7.4); 5	3.9 3.5 5.1
Body projection 4 Caudal apparatus Legs I–III Toe 1	9.1 15.2 10.3	9.0 ±1.52 (6.6–10.8); 5 18.8 ±4.27 (14.0–23.3); 5 10.9 ±0.50 (10.3–11.5); 4	? 8.0 9.1
Toe 2 Toe 3 Toe 4	7.9 19.7 11.4	8.2 ±1.83 (6.5–10.8); 4 18.6 ±1.06 (17.6–19.7); 4 11.7 ±1.93 (9.5–14.2); 4	4.7 13.3 9
Toe 5 Toe 6 Leg IV Toe 1	20.6 12.4 -	21.8 ±1.43 (20.6–23.4); 3 14.0 ±1.38 (12.4–15.0); 3 - (17.5–20.4); 2	14.7 9.8 12.3
Toe 2 Toe 3 Toe 4	- 15.5 15.7	- (25.6); 1 13.3 ±2.70 (10.3–15.5); 3 13.4 ±2.60 (10.6–15.7); 3	15.5 9.9 10.4
Toe 5 Toe 6 Gonopore - Anus	25.7 19.1 10.8	- (25.7–27.5); 2 18.8 ±1.01 (17.1–19.1); 3 9.0 ±2.21 (6.6–11.1); 5	18.2 11.0 -