Paraustrorhynchus sinensis Wang & Lin, 2019

Lin, Yitao, Reygel, Patrick, Feng, Weitao, Chen, Jiajia, Tessens, Bart, Van Steenkiste, Niels W. L., Schockaert, Ernest R., Artois, Tom J. & Wang, Antai, 2019, Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae), Zootaxa 4550 (3), pp. 357-373 : 362

Paraustrorhynchus sinensis Wang & Lin n. sp.

( Figs. 3–4 )

Locality. Same as P. shenda n. sp.

Material examined. One whole mount designated holotype: PLA-Po61. Paratypes PLA-Po062–064, three whole mounts; PLA-Po065-1–065-3, three whole mounts of prostate stylet type II and III; PLA-Po066-1–066-6, six serially-sectioned (sagittal) specimens and PLA-Po066-7, one serially-sectioned (horizontal) individual.

Etymology. The species name refers to the country where it was discovered.

Diagnosis. Species of Paraustrorhynchus with a mid-dorsal dark-blue pigment stripe. Prostate stylet type II ± 75 µm long, curved, outer stylet with proximal longitudinal slit. Prostate style type III ± 38 µm long, ± 40 µm wide proximally, ±12 µm wide in the middle and ±30 µm distally, consisting of a common proximal plate with two arms. Both arms broadened distally, one being broader than the other one, which is more or less boot-shaped. Distal rim of both arms provided with teeth.

Description. Habitus and internal morphology identical to that of P. shenda n. sp. ( Fig. 1A,B , 4A ), including the dorsal blue longitudinal pigment stripe. The prostate stylet type II is 7 0–80 µm long (x‾ = 75 µm; n = 3). It has a longitudinal slit ending at the stylet's midpoint. The stylet tapers gradually to end in a sharp distal point ( Fig 3 A–C, 4B). The proximal 3/4 of the stylet curves slightly and the distal 1/4 makes a 100° turn. The inner stylet can be followed over the whole length of the outer stylet, except in the proximal 1/4 of the stylet. The outer stylet has a funnel-shaped base, measuring 8–11 µm in width (n = 2). The funnel of the inner stylet narrows abruptly at about halfway along the length of the outer stylet and broadens again, gradually alongside the outer stylet. The prostate stylet type III consists of three parts: a proximal triangular plate with two extending long arms. Measurements of the prostate stylet type III (n = 2): length 33–42 µm; proximal width 38–42 µm; width in the middle 10–13 µm; distal width: 25–34 µm. The two arms, one boot-shaped and one plate-like, are curved towards each other and broaden distally. The distal ends of both arms are serrated, the plate-like arm shows large teeth (up to 7 µm in length) ( Fig. 3 D–I, 4C).

Figures

FIGURE 1. Paraustrorhynchus shenda n. sp.: (A) live specimen; (B) squeezed live specimen; (C) reproductive organs (partim); (D) egg; (E–G) prostate stylet type II; (H–J) prostate stylet type III.

FIGURE 3. Paraustrorhynchus sinensis n. sp.: (A–C) prostate stylet type II; (D–G) prostate stylet type III; (H–I) prostate stylet type III, more squeezed. Scalebar: 10 µm.

FIGURE 4. Paraustrorhynchus sinensis n. sp.: (A) habitus from a live animal; (B) prostate stylet type II; (C) prostate stylet type III.