Onuphis pancerii Claparède, 1868

Gil, João & Machado, Margarida, 2014, A new species of Onuphis (Polychaeta: Onuphidae) from Southern Portugal, with comments on the validity of O. pancerii Claparède, 1868, Zootaxa 3860 (4), pp. 343-360 : 356-357

Onuphis pancerii Claparède, 1868

Onuphis Pancerii — Claparède 1868: 438 –440, pl. 8 figs. 1, 2 H; Claparède 1869: 202; Claparède 1870: 387, pl. 5 fig. 5. Not Onuphis Pancerii — Rioja 1918: 39 –43, figs. 10 a–h (= Onuphis eremita Audouin & Milne-Edwards, 1833 ).

Remarks. Onuphis pancerii Claparède, 1868 is normally considered as a junior synonym of O. eremita Audouin & Milne-Edwards, 1833 , but taking into account the more restrictive definition of this species accepted today, it should be considered as a valid Mediterranean species. O. pancerii was described by Claparède (1868) from the Gulf of Naples, who refers to it as being very common but normally misidentified as Diopatra neapolitana . It was commonly used as bait by the Napolitan fishermen, who named it as “ esca di palo canita ”, whilst Diopatra neapolitana was known by the less elaborate name “ esca di palo ” ( Claparède 1869: 202). This denotes that not only the species was very common and easily accessible for bait digging, occurring probably at shallow water, but also that fishermen could easily recognize both species with the naked eye. This could be due to differences in morphology, ethology or ecology of the two species.

The original description of O. pancerii does not detail some important taxonomic characters useful today, but the species can still be separated from O. eremita based on the presence of two anterior chaetigers with bi– and tridentate pseudocompound hooks, as opposed to 3 chaetigers possessing tridentate pseudocompound hooks, respectively (see also table 1).

In the original description Claparède (1868: pl. 8 fig. 2 H) pictured the species as having a right maxilla III present, something that would be unique in the family. However, Claparède himself rectified that lapsus in a proceeding work, providing a corrected drawing of the maxillae ( Claparède 1870: pl. 5 fig. 5). As stated by the author ( Claparède 1870: 387), “ Le dessin [from the publication of 1868] avait été fait à Genève d’après une préparation de Naples. Je suis frappé de l’absence du paragnathe droit, absence que je n’avais pas remarquée à Naples. Persuadé que le paragnathe avait disparu par un accident de la préparation, je l’ai rétabli à tort dans le dessin du côté droit.”

After its description, O. panceri has only been referenced once, by Rioja (1918), who identified it, within some specimens collected at Santander ( Spain). He compared his specimens with one specimen from the Stazione Zoologica Anton Dohrn, in Naples, and found both populations to be similar, but differing slightly to Claparède’s description. The description given by Rioja (1918) fits quite well the description of O. eremita , except that the pseudocompound hooks of chaetigers 1–3 are stated to be bi– and tridentate, instead of only tridentate. Fauvel (1923) referred the population from Santander to the species O. eremita , and considered O. pancerii as being a junior synonym of O. eremita .

A search for specimens that could fit the original description of Onuphis pancerii Claparède, 1868 was performed through loan of material from the collections of Stazione Zoologica Anton Dohrn, in Naples. However, all studied specimens (12 specimens from Salerno, Campania, 3 specimens from Uccellina, Toscana, and 3 specimens from the mouth of the Tiber, Lazio; no further information available) were identified as O. eremita , with the exception of an Aponuphis sp. specimen from Ucellina. Nevertheless, only one of the studied lots was from Southern Italy (Salerno).

A definitive statement on the validity of O. pancerii will depend on the discovery of new material, either fresh or within existing collections, that could fit the original description, as no type material is known to exist. Particularly important would be the study of topotype material from the Gulf of Naples, but it is possible that the species is restricted to a specific habitat at the type locality itself, or that it has a patchy distribution that renders a new finding difficult, as in the case of Onuphis farensis sp. nov. at the Ria Formosa. However, it is also possible that the original description by Claparède (1868) included several errors or misinterpretations of the morphology of the worms, and that it is a junior synonym of O. eremita , as it has been considered and accepted.

The possibility that the species was described based on specimens not fully developed can be disregarded, as Claparède described the worms as being 12 cm long, for 4–5 mm wide and 130 chaetigers, very likely indicating full sized adults.

Finally, the fact that in other geographic regions many species have very restricted distribution patterns ( Maekawa & Hayashi 1999) could explain the difficulty in finding further specimens of O. pancerii . The species is herein considered as being likely valid, and is therefore included in the synoptic table of Onuphis species (table 1) and in the key below.