Diphascon (D.) nelsonae, Pilato & Binda & Bertolani & Lisi, 2005
Pilato, Giovanni, Binda, Maria Grazia, Bertolani, Roberto & Lisi, Oscar, 2005, Four new species of the Diphascon nobilei group (Eutardigrada, Hypsibiidae), Journal of Natural History 39 (14), pp. 1029-1041: 1034-1035
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|Diphascon (D.) nelsonae|
Diphascon (D.) nelsonae sp. n.
( Figure 3 View Figure 3 ; Table I)
Emilia: Modena: Civago: eight specimens: holotype (slide N. 4928) and paratypes in chestnut wood leaves; Aeolian Island : Lipari (one specimen in a moss) sample, Panarea (two specimens in a moss sample) .
Description of the holotype
Body length 231 M m, colourless, eyes absent, cuticle smooth without pearls. Buccopharyngeal apparatus is shown in Figure 3A View Figure 3 . The bucco-pharyngeal tube is 46.4 M m long; the rigid buccal tube 21 M m long (pbf 545.2) and 2 M m wide (ptd 59.5). The stylet supports are inserted on the bucal tube at 63.7% of its length (ptd 563.7). The pharyngeal bulb (29 M m × 18.6 M m) has small apophyses, three rod-shaped macroplacoids and microplacoid, the septulum is absent. The first macroplacoid is 4.3 M m long (ptd 520.5), the second 4.0 M m (ptd 519), the third 6.5 M m (ptd 530.9), microplacoid 1.6 M m (ptd 57.6); the entire placoid row 17.7 M m in length (ptd 584.3) including the microplacoid, 15.5 M m (ptd 573.8) excluding it.
The claws ( Figure 3B, C View Figure 3 ) have accessory points on the main branches; the claws of the hind legs ( Figure 3C View Figure 3 ) have the basal portion enlarged with the basal margin indented and prolonged in one medial and one lateral thickening. The branches are normally developed and not particularly wide. On the first three pairs of legs ( Figure 3B View Figure 3 ) the external claws have a slightly developed basal indentation; the basal margin of the internal claws is smooth.
The internal claws are 7 M m long (ptd 533.3) on the second and third pairs of legs, the external claws of the same pairs of legs are 10.5 M m long (ptd 550); on the hind legs the anterior claws are 7.9 M m long (ptd 537.6) and the posterior claws 11.5 M m (ptd 554.8).
A cuticular bar is present near the internal claws on the first three pairs of legs. Two exuviae with three and four smooth eggs were found.
The paratypes are similar to the holotype. In Table I the dimensions of some structures of the smallest and of the largest measured specimens are indicated.
The species is named nelsonae in honour of the tardigradologist, our dear friend, Diane Nelson (Department of Biological Sciences, East Tennessee University, Johnson City).
Diphascon nelsonae sp. n. differs from D. nobilei in the following features: entire placoid row, and particularly the second and third macroplacoid, longer both with respect to the body length and to the buccal tube length ( Table I), claws more slender with longer secondary branches, claw basal spines less evident (absent in the internal claws of the first three pairs of legs).
The new species differs from D. serratum in having the support of the stylet inserted on the buccal tube in a more cephalic position ( Table I), claws longer ( Table I) and more slender with longer secondary branches, anterior and posterior claws of the hind legs are more different in shape and size from one another ( Table I; Figures 2 View Figure 2 , 3 View Figure 3 ).
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