Obrimoposthia wandeli (Hallez, 1906)

Sluys, Ronald & Kawakatsu, Masaharu, 2005, Biodiversity of marine planarians revisited (Platyhelminthes, Tricladida, Maricola), Journal of Natural History 39 (6), pp. 445-467 : 454-455

Obrimoposthia wandeli (Hallez, 1906)

( Figures 14–15 )

Synonymy: Procerodes sanderi [Hauser, 1987].

Material examined

ZMA V.Pl. 951.1, King George Island, South Shetland Island, 1983, sagittal sections on 15 slides; V.Pl. 951.2, ibid., whole mount on one slide; V.Pl. 951.3, ibid., sagittal sections on 13 slides; V.Pl. 951.4, ibid., sagittal sections on 13 slides; V.Pl. 951.5, ibid., transverse sections on 19 slides; V.Pl. 951.6, ibid., horizontal sections on eight slides.

Comparative discussion

Without further comments, but after having studied relevant material, Sluys (1989) synonymized P. sanderi with O. wandeli (Hallez, 1906) . Here we further substantiate this taxonomic conclusion through re-examination of material from the original samples of P. sanderi that was made available to us by Prof. Hauser.

In a Portuguese publication, Hauser ( Anonymous 1987) described the finding of the presumed new species Procerodes sanderi [Hauser, 1987] (authorship in square brackets, according to Rec. 51D of the ICZN 1999) from King George Island of the South Shetland Islands. Specimens were collected and fixed in 1983 while live specimens were also brought back to the UNISINOS laboratory in Sao Leopoldo for further examination. Hauser ( Anonymous 1987) described the external features of the animals and provided a clear photograph of living animals. It was stressed that the animals moved in a way different from that observed in congeneric species in that specimens of P. sanderi exhibit solely a looping type of locomotion and do not show the usual gliding movement of many other planarians. Further it was claimed that the anatomy of the copulatory apparatus of P. sanderi differs from congeneric species but, unfortunately, the paper did not give any illustrations to clarify these differences.

The external appearance of the preserved specimens and the dorsal view of a cleared whole mount, showing the copulatory apparatus ( Figure 14 ), are in close agreement with the situation documented for O. wandeli (cf. Sluys 1989: figures 138, 140). Furthermore, reconstruction of the copulatory apparatus of the animals from King George Island clearly revealed the features that are characteristic for O. wandeli : T-shaped bursal canal and diverticulum, copulatory bursa situated latero-dorsally to the male atrium, tip of penial papilla folded within atrium, basal part of penial papilla with extremely thick, annular zone of circular muscle ( Figure 15 ).

The exclusively looping type of locomotion of presumed P. sanderi (observed by R.S. when he visited Hauser’s laboratory in 1994) can also be observed in other maricolans, with the difference that in these species this type of movement is usually observed more occasionally (cf. Sluys 1989) .

That specimens of O. wandeli could be newly collected from King George Island during expeditions in 1983 is unsurprising in view of the fact that Hallez (1913) reported the species from the same locality.

Figures

Figures 14–16. Obrimoposthia wandeli and Procerodella asahinai. (14) O. wandeli, V.Pl. 951.2, photomicrograph of whole mount. (15) O. wandeli, V.Pl. 951.3, photomicrograph of sagittal section through the copulatory apparatus. (16) P. asahinai, photograph of the pond on Hegura-jima Island.