Batillipes potiguarensis Santos, 2017

Santos, Érika, Gomes Jr, Edivaldo, Rocha, Clélia M. C. da, Bartels, Paul J. & Fontoura, Paulo, 2018, A closer look at Batillipes dicrocercus and new records of Batillipes potiguarensis (Tardigrada: Arthrotardigrada) from the Brazilian coast with comments on intra- and interspecific variability, Iheringia, Série Zoologia (e 2018041) 108, pp. 1-10 : 2-6

Batillipes potiguarensis Santos ,

da Rocha, Gomes Jr & Fontoura, 2017

Material examined: 35 specimens (18 females, 5 males and 12 juveniles) collected in Campos Basin ; and 29 specimens (11 females, 5 males and 13 juveniles) collected in Potiguar Basin, both stations located on the Brazilian Coast .

Description of the examined specimens. Batillipes specimens with 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. BodY length (caudal apparatus not included) between 105-257 µm ( Fig. 1 ). Four pairs of blunt ventrolateral body processes are present: a lateral expansion between the head and the first pair of legs; two small lateral processes between the first three pairs of legs and well-developed blunt lateral processes between legs III and IV ( Figs 1, 2 ). Occasionally, the blunt lateral body projections can present a small protruding tip. In some specimens, the lateral projection between the first and second pair of legs is not visible. The caudal apparatus exhibits high variability: in the majority of the specimens it is bifurcated, composed of two spines inserted in a swollen base ( Figs 1 , 3 ). In some specimens, the spines are two short spikes of about 9.7 µm, while other specimens exhibit two longer spines, reaching 23.8 µm. In a few specimens the caudal apparatus is asymmetric and only a single small spike is present ( Fig. 4, 5 ) or it is restricted to a conspicuous semicircle-shaped protrusion without anY spikes or spines at all ( Fig. 2 , 6 ).

Dorsal cuticle punctated, with evident transverse folds ( Fig. 7 ). Dorso-lateral punctation larger (about 7-10 pillars / 10 µm, and each pillar with about 1 µm high) and more widelY spaced than mid-dorsal punctation (about 12- 15 pillars / 10 µm) ( Fig. 7 ). In the lateral processes between legs III and IV the cuticle is punctated. The ventral surface, also with transverse folds, is more finelY punctated.

Head bearing eleven cephalic appendages. The median cirrus, with cirrophore. Internal cirri inserted dorsally on the frontal edge of the head with cirrophores. External cirri with indistinct cirrophores, inserted more ventrally, near the lateral cirri A and primary clavae. The lateral cirrus is located dorsally in relation to the unconstricted, but wrinkled, tubular primary clava. These two appendages share a common pedestal. A van der Land’s organ is present at the base of the primary clava that exhibits a terminal pore. In the frontal edge of the head, well-developed papillarY secondarY clavae are visible ( Fig. 1 , arrowhead). All cephalic cirri, including external cirri, and lateral cirri have an optically dense dot (dark when observed under PHC) near their swollen tips. Indentations between the external cephalic cirrus and the pedestal bearing the primary clava and lateral cirrus were not seen.

Eye spots not observed. Ventral mouth opening in a protruded cone. Ovoid pharyngeal bulb. Placoids not visible after slide mounting.

Sense organs with swollen tips on legs I and IV and spines on legs II and III. TheY are similar in length in the first three pair of legs (rarely sense organ on leg I is shorter than on legs II and III). The sense organ on leg IV is consistently the shortest and divided into a cirrophore and a distal portion with a basal van der Land’s organ ( Fig. 6 , arrowhead). SharplY pointed cirri E are present ( Fig. 4 ).

Telescopic legs with long toes with spatula-like suction discs with straight frontal edges and with short and thin braces ( Figs 1 , 8 ). The frontal edge of tarsi is oblique in the first three pair of legs, with toes inserted at different levels ( Fig. 8 ). In these three first pairs of legs, toe 2 is the shortest, toes 3 and 5 are the longest and toes 1, 4 and 6 are medium sized ( Fig. 1 ). In the fourth pair of legs, medial toes 3 and 4 are of equal lengths (toe arrangement pattern A, according to SANTOS et al., 2018). Toes 2 and 5 are the longest and similar to each other; toes 1 and 6, also similar to each other, are of intermediate length ( Figs 1, 2 , 8 ).

In females, the gonopore is rosette-shaped delimited by four punctate cuticular platelets, two anterior and two posterior, forming a groove running toward the anus. Males have a circular gonopore with a cuticular crescent shaped fold.

Four-toed larvae were not found.

Morphometric data are provided in Table I.

Figures

Figs 1,2. Batillipes potiguarensis Santos, Rocha, Gomes Jr & Fontoura, 2017: 1, specimen from our samples with a bifurcated caudal appendage. The arrowhead shows the well-developed secondarY clava; 2, holotYpe with a rounded caudal protrusion. Scale bars: 50 µm.

Fig. 3-8. Batillipes potiguarensis Santos, Rocha, Gomes Jr & Fontoura, 2017: 3, detail of a bifurcated caudal appendage; 4, posterior portion of the body, showing an asymmetric caudal appendage with one short spike only (arrowhead); 5, posterior portion of the body showing an asymmetric caudal appendage with one short spine only (white arrowhead).The black arrowhead shows the blunt lateral projection between legs III–IV; 6, caudal appendage without spines. The sense organ on leg IV is visible (arrowhead); 7, dorsal cuticle with visible folds and punctation not uniformlY distributed; 8, detail of the first leg showing the oblique tarsus and spatula-like toe discs. Scale bars: 10 µm.