Paraustrorhynchus elixus ( Marcus, 1954 ) Karling & Schockaert, 1977

Artois, Tom J. & Tessens, Bart S., 2008, Polycystididae (Rhabditophora: Rhabdocoela: Kalyptorhynchia) from the Indian Ocean, with the description of twelve new species, Zootaxa 1849, pp. 1-27 : 9-10

Paraustrorhynchus elixus ( Marcus, 1954) Karling & Schockaert, 1977

( Fig. 2 D–G, J)

Syn. Austrorhynchus elixus Marcus, 1954

Known distribution. The Brazilian coast: Bay of Santos and the Island of São Sebastião ( Marcus 1954).

New localities in the Indian Ocean. English Point, Mombasa ( Kenya): green algae (5 m) (October 1987).

New localities outside the Indian Ocean. New Caledonia, Nouméa, Nouville, algae covered with sediment from the lagoon near to the asylum (10/08/2003). New Caledonia, Nouméa, Magenta, large algae covered with sediment and small epiphytes from a pool on the beach near to the mangrove area (22/08/2003).

Material. One animal from Kenya studied alive and mounted. Two whole mounts (including the lectotype) and two serially-sectioned specimens from Brazil ( SMNH). One animal studied alive and whole mounted and one sectioned specimen from New Caledonia.

Remarks. A detailed description of the species can be found in Marcus (1954), with additions made by Karling & Schockaert (1977). Our observations on the new specimens are completely in accordance with these descriptions. The prostate stylet type II ( Fig. 2 E, G) is identical in the specimens from all three localities, and is a simple hook with an asymmetrical proximal opening [not mentioned or depicted by Marcus (1954) or Karling & Schockaert (1977)]. It is very short, only 27 µm long in the specimen from New Caledonia, 32 µm in the specimen from Kenya ( Fig. 2 E) and 33 µm in a specimen from Brazil [ Fig. 2 G, same specimen as depicted by Karling & Schockaert (1977, Fig. 25)]. The prostate stylet type III ( Fig. 2 D, F) [“complex cuticular apparatus” of Karling & Schockaert (1977)] is very complex, consisting of a stalk and a S-shaped plate that is attached to it. This stylet is easy to study in one specimen from Brazil ( Fig. 2 F) and in the specimen from New Caledonia. It is almost identical in both. In the lectotype and in the specimen from Kenya ( Fig. 2 D) this stylet is deformed through squashing. Especially on the lectotype it is very difficult to distinguish the different parts of this stylet, and therefore we do not further consider this specimen. The different parts of the prostate stylet type III can, however, be recognised on the specimen from Kenya. These different parts are a stalk, an S-shaped plate and hook, indicated on Figs 2 D & F by a full, striped and dotted arrow respectively. The measurements we took on the different specimens are as follows: Brazil: stalk: 77 µm, S-shaped plate: 64 µm, hook: 21 µm; New Caledonia: stalk: 78 µm, S-shaped plate: 63 µm, hook: 17 µm; Kenya: stalk: 92 (?)

µm, S-shaped plate: 62 µm, hook: 17 µm. The stalk of the Kenyan specimen is recurved, and very difficult to measure properly. It might be shorter than indicated here. An overview of the measurements is given in Table 4 .

Figures

FIGURE 2. Paraustrorhynchus neleae n. sp. A, Habitus (from a live animal). B, H, Prostate stylet type II (from the holotype). C, I, Prostate stylet type III (from the holotype). P. elixus. D, Prostate stylet type III (from a specimen from Kenya). E, Prostate stylet type II (from the same specimen from Kenya). F, Prostate stylet type III (from a specimen from Brazil). G, Prostate stylet type II (from the same specimen from Brazil). J, Prostate stylet type III (from a specimen from New Caledonia). Arrows explained in the text.