Onuphis hanneloreae Arias, 2016, sp. nov.
Creators: name: Arias, Andrés
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Eunicida
Onuphidae
Onuphis
Onuphis hanneloreae

description: Onuphis hanneloreae sp. nov.
Figures 7–12; Tables 1, 3
Type material. Holotype (MNCN 16.01 /17458), Igrejinha beach (16º 36’N – 22º 53’ W), intertidal to shallow subtidal, SE of Sal island, Cape Verde archipelago, West Africa, tropical eastern Atlantic, coll. A. Arias July 2012; paratype (MNCN 16.01 /17459) same data as holotype.
Non-type material. Juvenile specimens of different sizes, same data as holotype, coated with gold for SEM studies (MNCN 16.01/17460).
Type locality. Intertidal to shallow subtidal sands of Igrejinha beach 16º 36’N– 22º 53’ W, SE of Sal island, Cape Verde archipelago, West Africa, tropical eastern Atlantic.
Diagnosis. Prostomium anteriorly extended. Eyespots absent. Palps reaching chaetiger 2, lateral antennae reaching chaetiger 5–6 and median antenna chaetiger 4. Ceratophores long and strongly ringed, palpophores with 10–11 rings, lateral antennophores with 15–16 and median antennophore with 7–10 rings. Subulate ventral cirri in first six chaetigers; distinct subulate postchaetal lobes in first 10–15 chaetigers. Interramal papillae at base of dorsal cirrus absent. Bi-, tri- and quatridentate pseudocompound hooks in first three chaetigers; slender long-appendaged hooks absent. Subacicular hooks from chaetiger 10. Flat pectinate chaetae with 10–11 teeth. Single branchial filaments from chaetiger 1 to 16–21, thereafter number increasing to maximum of three to four. Tube cylindrical in shape, parchment-like and externally covered with sand-grains.
Description. Small and slender species. Both type specimens incomplete. Length of holotype 11.5 mm for 30 chaetigers, width 0.8 mm; paratype 8.5 mm long, 0.9 mm wide with 28 chaetigers.
Colour pattern consisting of: 1–2 circular brown subcutaneous spots on underside of ceratophores of antennae and palps; frontal lips with brown spots at base; three large, sometimes fused, dark brown spots on peristomium, occupying almost entire surface, first six chaetigers almost uniform cream to light brown coloured, subsequent chaetigers with a brown coloured band at posterior margin of segment forming transversal banding pattern (Fig. 7). Prostomium subtriangular with pair of subulate frontal lips (Fig. 8 B). Eyespots absent. Palps reaching chaetiger 2 with 9–10 basal rings and longer distal ring in palpophores. Lateral antennae reaching chaetiger 5–6 with 14–15 basal rings in antennophores, median antenna reaching chaetiger 4 with 6–9 basal rings, all three antennophores with slightly longer distal ring (Figs 7 B, 8 A, B). Palpostyles and antennostyles with irregular longitudinal rows of sensory buds. Nuchal grooves straight with narrow middorsal separation (Fig. 8 C). Peristomial cirri inserted distally on peristomium slightly lateral to lateral antennae, shorter than length of peristomium not exceeding anterior margin of prostomium (Fig. 7 B).
Anterior chaetigers (1–3) slightly longer than those following (Figs 7, 8 A). First three pairs of parapodia modified, not enlarged, directed slightly anterolaterally, with low prechaetal fold, rounded prechaetal lobe and spindle-shaped postchaetal lobe, latter longer than base of parapodium; digitate dorsal cirrus as long as postchaetal lobe, ventral cirrus shorter than postchaetal lobe (Fig. 9 A). Subulate ventral cirri in six chaetigers, pad-like thereafter (Fig. 7 D). Ventral glandular pads with irregular cuticular pore pattern (Fig. 10 A). Postchaetal lobe as distinct subulate lobe in first 10–15 chaetigers, becoming smaller and conical knobs in shape thereafter. Interramal papillae at base of dorsal cirrus absent.
Branchiae as single filament from first chaetiger to chaetiger 21 in holotype, to chaetiger 16 (right) –17 (left) in paratype (Fig. 9 A), usually longer than dorsal cirri, thereafter number of filaments increasing to maximum of three to four (Figs 9 B, 10B), being present to end of fragments.
Aciculae yellowish with pointed tips, generally three per parapodium. Hooded pseudocompound hooks in first three chaetigers. First three parapodia with following chaetal complement going from superior to inferior part of chaetal fan: one to two simple chaetae, three protruding distal tips of aciculae and four to five pseudocompound hooks with bi-, tri- (Fig. 9 C–E) and quatridentate tips (with two little denticles protuding directly from base of second distal tooth) (Fig. 10 E). All hooks with falcate hoods (Fig. 10 D) and of almost equal thickness and length of appendages (Figs 9 C–E; 10C). Slender long-appendaged hooks absent. Pseudocompound hooks replaced by limbate chaetae from chaetiger 4. Flat pectinate chaetae with 10–11 teeth, two per parapodium (Fig. 10 F) and hooded bidentate subacicular hooks from chaetiger 10 (Fig. 10 G). Mandibles with transparent poorly calcified cutting plates and slender shafts. Maxillae (Fig. 9 F) weakly sclerotised; maxillary formula (based on largest juvenile): Mx I = 1 + 1, Mx II = 7 + 7, Mx III = 8 + 0, Mx IV = 6 + 10, Mx V = 1 +1, Mx VI absent. Tube cylindrical in shape, parchment-like and externally covered with sand grains.
Etymology. It is a great pleasure to dedicate this new species to Dr Hannelore Paxton, whose significant contributions have greatly increased and improved the knowledge on this family and have brought about a modern view of their systematics.
Distribution and ecology. Onuphis hanneloreae sp. nov. is known from the intertidal and shallow subtidal sandy flats and patchy sandy areas between rocks of Sal, the second easternmost island of Cape Verde archipelago, West Africa, tropical eastern Atlantic (Fig. 1).
Remarks. Onuphis hanneloreae sp. nov. belongs to the O. eremita species complex (Table 1). Within this group the new species resembles the European O. pancerii and the Japanese O. shijikiensis Maekawa & Hayashi, 1999 in having both bi- and tridentate pseudocompound hooks in the first three chaetigers and subacicular hooks from chaetiger 10. However O. hanneloreae sp. nov. and O. pancerii differ from the Japanese species by the presence of quatridentate pseudocompound hooks in anterior modified chaetigers and in the number of hooks per fascicle, bearing five hooks, in contrast O. shijikiensis only has three hooks in each fascicle (Maekawa & Hayashi 1999). Onuphis hanneloreae sp. nov. clearly differs from O. shijikiensis in its colour pattern and O. pancerii by its smaller size and the absence of the interramal papillae at the base of dorsal cirri on anterior non-modified chaetigers (present in O. pancerii). Furthermore, their reproductive biology is different, O. hanneloreae sp. nov. is a brooder species that undergoes direct development; by contrast O. pancerii is a broadcast spawner with indirect development (Arias & Paxton, 2014).
Reproductive biology and ontogeny. Among the type material, the paratype specimen was collected within its tube together with three vermiform juveniles. The brooded juveniles range from 3.9–4.2 mm in length for 28–39 chaetigers and measure 0.34–0.35 mm in width (Table 3), with the largest presenting a colour pattern on the dorsum of the anterior chaetigers similar to the adults. All juveniles have a pair of small eyespots on prostomium, small peristomial cirri, well developed frontal lips, palps and antennae and the ceratophores of the largest two with three to four rings. The parapodia are well developed with dorsal cirri on the first 20 to 30 chaetigers and subulate ventral cirri on the first two to three chaetigers. Single branchiae are present on chaetigers 6 and 7; the pygidium bears two pairs of slender anal cirri.
. chaetiger; LA. lateral antennae; VC. ventral cirri; Ant. Prov. anterior provisional; Post. prov. posterior provisional.
In addition, four recently settled juveniles were collected from the same location. The specimens range from 5.3–6.4+ mm in length for 46–66+ chaetigers and measured 0.40–0.52 mm in width (Table 3). Three of them have a brownish pigmented colour pattern. All have branchiae, the two larger ones have single branchiae from chaetiger 2, the smaller one has single branchiae from chaetiger 5 and the 57 chaetiger specimen has branchia from chaetiger 3.
The chaetal composition of juveniles differs from that of adults and has been detailed for these O. hanneloreae specimens in Fig. 11. The smallest examined juveniles have two to four compound hooks in the first three pairs of parapodia. In the 28- and 33- chaetiger specimens they have only bidentate and the 39-chaetiger specimen has bi- and tridentate hooks. Parapodia 4–9 have two limbate chaetae and two kinds of anterior provisional subacicular hooks (SAHs): one with a relatively large appendage in the medial position of the parapodium (Fig. 12 A) and two ventral hooks with smaller appendages (Fig. 12 B, C). Two posterior provisional SAHs start on chaetiger 10 (Fig. 12 D), being present to almost the end of the body. The brooded juveniles lack permanent subacicular hooks and pectinate chaetae. The recently settled juveniles have bi- and tridentate compound to pseudocompound hooks on the first three parapodia. They have four to five hooks (compound and pseudocompound) and one limbate chaeta in the first two parapodia and two or three compound hooks and two or three limbates in the 3rd parapodium. The anterior provisional SAHs are now restricted to chaetiger 7–8 to 9, with chaetigers 4–6 or 7 lacking any hooks, having only limbate chaetae. Two permanent SAHs are present from chaetiger 10–37 or 38 when first one (Fig. 12 E), and then both permanent SAHs are replaced by posterior provisional SAHs. A flat pectinate chaeta with 9–10 teeth is present from chaetiger 10 to 20–30.
The branchial development commences when juveniles consist of about 30 chaetigers. The branchiae start on chaetiger 6, from there they spread more posteriorly but also anteriorly, passing through intermediate forms with branchiae starting on chaetiger 5, 4, 3 and 2. When the worm has attained a width of about 0.8 mm, or about twothirds of its maximum size, the branchiae begin on chaetiger 1 which is considered here as representing the adult condition of the species. Similar patterns in branchial progression have been observed in species of Onuphidae (Paxton 1996, Arias & Paxton 2015a).
description: Published as part of 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, pp. 481-511 in Zootaxa 4168 (3) on pages 493-501, DOI: 10.11646/zootaxa.4168.3.3, http://zenodo.org/record/155271