Onuphis Audouin & Milne Edwards, 1833

Arias, Andrés, 2016, Onuphi s and Mooreonuphis (Annelida: Onuphidae) from West Africa with the description of three new species and the reinstatement of O. landanaensis Augener, 1918, Zootaxa 4168 (3), pp. 481-511 : 484

Genus Onuphis Audouin & Milne Edwards, 1833

Onuphis Audouin & Milne Edwards, 1833: 225 .

Type species. Onuphis eremita Audouin & Milne Edwards, 1833: 226 by subsequent designation of Malmgren 1866: 180. Gender: feminine.

Diagnosis. Prostomium often anteriorly extended; with frontal lips. Antennae and palps with ceratophores usually with 10–25 rings and short to moderately long styles, palpostyles shorter than palpophores. Nuchal grooves straight. Peristomial cirri present. Anterior three to four (rarely two or five) pairs of parapodia modified but not enlarged. Ventral cirri subulate on anterior four to six chaetigers; dorsal cirri moderately long. Branchiae rarely absent, usually present from chaetiger 1, rarely 3–6; single or pectinate filaments (maximum 12). Hooks of modified parapodia usually tridentate (rarely only bidentate, sometimes bi- to multidentate) pseudocompound with relatively short hoods; median hook slightly larger but not becoming simple and changing to large median hook. Hooks varying specifically, from all having appendages of almost equal thickness and length to being clearly differentiated into slender long-appendaged and robust short-appendaged hooks. Dorsal limbate chaetae from chaetiger 1, ventral limbate chaetae replacing pseudocompound hooks from chaetiger 4 or later until replaced by bidentate hooded subacicular hooks usually from chaetiger 9–14. Tubes round in section, ranging from thin mucous to tough parchment-like inner layer covered with extraneous particles.

Remarks on West African species. Until recently, O. eremita was considered to be cosmopolitan in its distribution and was the only Onuphis species that has been repeatedly reported from West Africa (excluding the records of Onuphis spp. that actually belong to other onuphid genera like Nothria or Paradiopatra ). However, most of these reports merely list the species without any description of the specimens found and in the others, the specific features given could refer to any of the eastern Atlantic species of the O. eremita spp. complex.

Onuphis landanaensis was described by Augener (1918) based on several specimens collected by A. Hupfer at different localities along the Gulf of Guinea (West Africa) in shallow waters. These localities were: Sesstown in Liberia ; Whydah , located in the area of the present-day country of Benin (referred by Augener as Dahomey , a French colony of the epoch); the Nyanga estuary in the current nation of Gabon (referred as French Congo , an old French colony); Landana in the present-day country of Angola (referred as Cabinda, currently a province of Angola). By failing to designate the holotype, the type locality of the species would comprise all sites of origin of the syntypes (International Code of Zoological Nomenclature, art. 72.2.3). Shortly afterwards O. landanaensis was considered as a synonym of O. eremita by Fauvel (1923), remaining as such until the present time.

The description of Onuphis landanaensis in Augener (1918) , although quite extensive and describing certain features in great detail, does not mention many characters used presently to diagnose Onuphis species. The features of possible diagnostic value are the following: colour pattern consisting of dorsal red-brownish bands in anterior segments, transforming to two bands or spots in the median region, anterior end darker coloured with high iridescence; prostomium with a small pair of eyespots; first six chaetigers with cirriform (subulate) ventral cirri; distinct subulate postchaetal lobes in the first 10 chaetigers; first three or four chaetigers with compound to pseudocompound characteristically tridentate hooks; pectinate chaetae short and distally oblique; single branchiae from chaetiger 1 to 17–19, then branching with up to 5 to 7 filaments ( Augener 1918).

As commented above, the information in Augener (1918) shows that the description of O. landanaensis was based on several specimens from different localities, the farthest apart ( Liberia and Angola) about 2500 km in a straight line and the given features varying between individuals from different locations. This suggests that the description was potentially based on two or more different species. Fortunately, the types (syntypes) of O. landanaensis have been preserved to date in the Zoologisches Museum of Hamburg ( Germany) and were reexamined by the author. The type material consists of two single vials registered as “V. 868” and “V. 8674” respectively, both labelled as “ Onuphis landanaensis Aug. Original ” but differing in the locality of origin of the samples. The vial “V.868” contains six specimens and two posteroir fragments from off Nyanga estuary -“Nyanga- Fluss ”- ( Gabon) and the vial “V. 8677” holds two specimens from Whydah ( Benin) . At first glance the specimens from Nyanga estuary and Whydah looked quite different, the former have an uniform, highly iridescent whitish colour ( Fig. 2 A) and the latter are slightly smaller with a characteristic colour pattern with brownish pigment ( Fig. 2 B) . A subsequent more detailed examination showed that both samples differ in important prostomial, chaetal and parapodial diagnostic features, evidencing that the specimens from Nyanga and Whydah are not conspecific. Although none of the two samples of specimens (Nyanga and Whydah) fit faithfully with the original description, the Whydah specimens display a series of characters (e.g. brownish colour pattern, small eyes on prostomium, only tridentate hooks in anterior chaetigers) that make them more consistent with the description and illustrations of Augener (1918) ( Fig. 3 ). Thus I chose to retain the name of O. landanensis for the Whydah specimens and designate these two specimens as lectotype and paralectotype respectively. Consequently, this new type material was used to formally redescribe and reinstate the species. On the other hand, the specimens from Nyanga estuary do not fit with Augener’s description as well as the the specimens from Whydah and are accordingly described as a new species— Onuphis augeneri sp. nov. —(see below).

Figures

FIGURE 2. Photomicrographs. Onuphis augeneri sp. nov. Holotype A, B (ZMH V. 868), Onuphis landanaensis lectotype C, D (ZMH V. 8674). A, anterior end, dorsal view; B, detailed view of dorsum under methyl blue staining; C, anterior end, dorsal view; D, detailed view of anterior end.

FIGURE 3. Onuphis landanaensis original line drawings of Augener (1918). A, anterior end, dorsal view; B, first parapodium, anterior view; C, median parapodium, anterior view; D, mandibles; E, maxillae; F, subacicular hook of median chaetiger; G, tridentate pseudocompound hook of modified chaetiger.