Doryphoribius bindae, Lisi, Oscar, 2011

Lisi, Oscar, 2011, Remarks on Doryphoribius flavus (Iharos, 1966), and description of three new species (Tardigrada, Hypsibiidae), Zootaxa 2834, pp. 17-32 : 25-28

Doryphoribius bindae sp. nov.

( Fig. 4 )

Material examined. Holotype (slide number 3609), nine paratypes and four exuviae with eggs (slide numbers 3610-3613, 3620-3623, 4170) mounted in polyvinyl lactophenol; South Africa: Tzitzikama, from a moss sample (data available from Binda, 1984).

Specific diagnosis. [Eye spots present*]; dorsal and lateral cuticle with a delicate reticulate sculpture consisting of very thin ridges forming a mesh with a tiny tubercle at each crossing. Anterior side of the first three pair of legs and dorsal side of the fourth pair of legs, swollen; these portions, together with the lateral side of the legs, with a very fine and dense reticulate sculpture. Bucco-pharyngeal apparatus of the Doryphoribius type; peribuccal papulae present, some of which were divided. A small dorsal tooth, difficult to see, is visible near the medial margin of each stylet sheath. Pharyngeal bulb with apophyses, two macroplacoids and no microplacoid or septulum. Claws of the Isohypsibius type with accessory points on the main branches; basal portion of the internal claws small and short, that of external claws longer and enlarged at the very base. Smooth lunules present, those of the internal claws small and very narrow; no other sclerified structures on the legs. Smooth eggs laid into the exuvium.

[*] = Not visible after mounting in polyvinyl lactophenol.

Description of the holotype. Body length 327.6 µm, colourless, eye-spots no longer visible, dorsal and lateral cuticle finely sculptured with a delicate reticular design ( Fig. 4 A, a paratype) formed by thin ridges forming a minute tubercle at each crossing ( Fig. 4 B, arrows). The mesh, slightly irregular in shape and size, increase in average size from the lateral to the dorsal cuticle and from the head to the posterior portion of the body, reaching their maximum between the third and the fourth pair of legs (largest mesh about 3.9 μm, pt = 10.6), decreasing slightly more caudally. Swollen portions and sculpture of legs not obvious due to the orientation of the holotype, but clearly visible on paratypes ( Fig. 4 C). The swollen portions, together with the lateral side of the legs, with a very fine and dense reticulate sculpture.

Bucco-pharyngeal apparatus of the Doryphoribius type ( Fig. 4D ). Peribuccal papulae present, some of which were divided, buccal armature consisting of only one small dorsal tooth, difficult to see, visible near the medial margin of each stylet sheath ( Fig. 4 E, arrows, a paratype). Buccal tube 36.7 µm long (11.2% of the body length) and 4.7 µm wide (pt = 12.8); stylet supports inserted at 71.3% of the buccal tube length (pt = 71.3); ventral lamina 22.3 µm long (pt = 60.8). Pharyngeal bulb could not be measured, with apophyses and two macroplacoids; microplacoid and septulum absent. Placoid row 13.7 µm long (pt = 37.3), first macroplacoid, slightly constricted in the middle, 7.8 µm long (pt = 21.3), second macroplacoid 4.4 µm (pt = 12.0).

Claws of the Isohypsibius type ( Fig. 4D , F), slightly different in shape and size on each leg; the basal portions of the inner claws are small and short, while those of the external claws are longer, wider, and expanded at the very base. Accessory points on the main branches. Smooth lunules present (those of the internal claws of the first three pairs of legs often difficult to see); no other sclerified structures on the legs. The measurements of the claws and the other structures are reported in Table 3 .

Holotype Slide N. 3609 Smallest paratype Slide N. 3620 Largest paratype Slide N. 3621 Remarks. The paratypes were similar to the holotype in both qualitative and metric characters ( Table 3 ). Smooth eggs (4–6) laid into the exuvium.

Etymology. The species is in honour of Prof. Maria Grazia Binda (University of Catania).

Type depositories. The type material is deposited in the Binda and Pilato collection (Museum of the Department of Animal Biology “Marcello La Greca”, University of Catania).

Differential diagnosis. Doryphoribius bindae sp. nov. differed from D. flavus by having a more delicate cuticular ornamentation formed by thinner ridges with a small tubercle at each crossing; the largest mesh diameter was nearly half that of D. flavus ( Table 5); and, unlike D. flavus , the leg sculpture of the new species was also observed on the swollen portion. D. bindae sp. nov. had only one dorsal tooth in the buccal cavity near the medial margin of each stylet sheath, whereas D. flavus had about four teeth visible on each side ( Figs. 1 B, 2C and 4E); and the claws of the new species were shorter ( Table 5) with slightly shorter secondary branches ( Figs.1 C, D, 2B, E and 4D, F).

The distinguishing features between D. bindae sp. nov. and D. polynettae were the lack of cuticular sculpture on the ventral surface (present on D. polynettae ); a more obvious dorsal cuticular sculpture with tubercles at each crossing of the ridges forming the mesh; and absence of pores or roughness on the cuticle; sculptured legs with swollen portions; only a pair of teeth in the oral cavity; and wider buccal tube.

Doryphoribius bindae sp. nov. differed from D. amazzonicus sp. nov. by having a more delicate reticulate cuticular sculpture due to the narrower ridges delimiting the mesh, which were smaller with respect to the body length ( Table 5); this difference did not emerge from the values of the pt index as the buccal tube of D. amazzonicus was longer with respect to body length ( Table 5). The tubercles at the ridge crossings were less protruding on D. bindae sp. nov. ( Figs. 3 B and 4B), thus appearing less evident, and the legs were sculptured. As mentioned above, D. bindae sp. nov. had a shorter buccal tube with respect to the body length ( Table 5) and, as a consequence, the values of the pt index relative to the buccal tube width, the placoids and claw lengths appeared slightly higher, whereas the percent values of the length of these structures with respect to body length appeared very similar ( Table 5).

D. bindae sp. nov. differed from D. quadrituberculatus above all by lacking dorsal gibbosities and having tubercles at the ridge crossings that form the mesh; sculptured legs with swollen portions; peribuccal papulae; only a pair of dorsal teeth in the oral cavity; and lunules at the base of the claws.

D. bindae sp. nov. differed from D. smokiensis by having eyes; a different type of cuticular sculpture; sculptured legs with swollen portions; only a pair of dorsal teeth in the oral cavity; far narrower buccal tube; lunules at the claw base; and other minor details.

Figures

FIGURE 4. D. bindae sp. nov. A, Cuticular sculpture of the caudal portion of a paratype; B, Caudal portion of the holotype: some tubercles are in focus (arrows); C, Leg of the second pair of a paratype, also sculptured on the swollen portion (arrow); D, Bucco-pharyngeal apparatus and first pair of legs of the holotype; E, Dorsal teeth of the buccal cavity (arrows) of a paratype; F, Claws of the fourth pair of legs of the holotype. Scale bar = 10 µm.

FIGURE 1. D. flavus. A, Dorso-lateral teeth (arrows) of the buccal cavity of a paratype; B, Bucco-pharyngeal apparatus of another paratype; C, Claws of the second and third pairs of legs of the same paratype as Fig. 1 B; D, claws of the fourth pair of legs of the same paratype as Fig. 1 B – C. Scale bar = 10 µm.

FIGURE 3. D. amazzonicus sp. nov. A, Cuticular sculpture of the caudal portion of the paratype; B, Caudal portion of the holotype, some tubercles are in focus (arrows); C, Bucco-pharyngeal apparatus of the holotype; D, Claws of the second and third pair of legs of the holotype. Scale bar = 10 µm.

Tables

TABLE 3. Measurements of selected morphological structures of the holotype and the smallest and largest paratype of Doryphoribius bindae sp. nov.; “ Styl. supp. insert. ” indicates the stylet supports insertion point on the buccal tube; “ % bo-le ” indicates the percentage ratio with respect to the body length (calculated for the buccal tube length, the placoid row, the claws and the largest mesh).

Characters	µm	pt	% bo-le	µm	pt	% bo-le	µm	pt	% bo-le
Body length	327.6	-	-	286.2	-	-	351.0	-	-
Buccal tube length	36.7	-	11.2	33.5	-	11.7	39.0	-	11.1
Buccal tube width	4.7	12.8	-	4.8	14.3	-	5.1	13.1	-
Styl. supp. insert.	-	71.3	-	-	70.0	-	-	71.6	-
Ventral lamina	22.3	60.8	-	19.3	57.6	-	25.0	64.1	-
Placoid row	13.7	37.3	4.2	12.4	37.0	4.3	14.5	37.2	4.1
I macroplacoid	7.8	21.3	-	6.9	20.6	-	9.1	23.3	-
II macroplacoid	4.4	12.0	-	4.7	14.0	-	4.7	12.1	-
I ex. claws	16.6	45.2	5.1	?	?	?	?	?	?
I int. claws	13.6	37.1	4.2	?	?	?	?	?	?
II ex. claws	17.2	46.9	5.3	14.7	43.9	5.1	16.8	43.1	4.8
II int. claws	14.2	38.7	4.3	12.9	38.5	4.5	?	?	?
III ex. claws	17.8	48.5	5.4	?	?	?	16.8	43.1	4.8
III int. claws	14.5	39.5	4.4	?	?	?	13.9?	35.6?	4.0?
IV ant. claws	15.5	42.2	4.7	14.2	42.4	5.0	?	?	?
IV post. claws	18.3	49.9	5.6	16.6	49.6	5.8	18.2	46.7	5.2
Largest mesh	3.9	10.6	1.2	3.6	10.7	1.3	4.8	12.3	1.4