Mooreonuphis wilsoni, Paxton, 2018

Paxton, Hannelore, 2018, Two new species of Mooreonuphis (Annelida: Onuphidae) from Australia, Zootaxa 4486 (4), pp. 589-600 : 595-598

Mooreonuphis wilsoni n. sp.

FigureS 5–6 ; Table 1

Material examined. Holotype: IncOmplete Specimen , 9 mm lOng (41 chaetigerS), 0.6 mm wide; EaStern BaSS Strait , 100 km NE Of NOrth POint, FlinderS ISland, RV ' TangarOa' CruiSe 81-T-1 StatiOn BSS 170 SEB, 31°51.8'S, 148°26.5'E, 130 m, fine Sand, Sled, 15 NOV 1981, cOll. R. WilSOn ( NMV F43634 ).

Paratypes: 6 incOmplete SpecimenS, 3.5–8 mm lOng (22–41 chaetigerS), 0.4–0.5 mm wide.

Same data aS hOlOtype ( NMV F 240185: 2 wet and NMV F 240186: 1 On SEM pin); WeStern BaSS Strait, 50 km SSW Of WarrnambOOl, VictOria, RV 'TangarOa' CruiSe 81-T-1 StatiOn BSS 190, 38°49.5'S, 142°35.4'E, 89 m, cOarSe Sand, dredge, 21 NOV 1981, cOll. R. WilSOn ( NMV F43645 : 1); WeStern BaSS Strait, 70 km SW Of Cape Otway, VictOria, RV 'TangarOa' CruiSe 81-T-1, StatiOn BSS 194, 39°26.3'S, 143°06.8'E, 115 m, Sand, Sled, 21 NOV 1981, cOll. R. WilSOn ( NMV F43649 : 1); TaSmania, 37 km NE Of Cape TOurVille, Freycinet PeninSula, RV 'Franklin', StatiOn SLOPE 85, 41°52.87'S, 148°37.93'E tO 41°59.56'S, 148°31.13'E, 124 m, cOarSe biOgenic graVel, trawl, 30 Oct 1988, cOll. GCB POOre et al. ( NMV F233686: 1 On SEM pin).

Additional material examined: 4 cOmplete Settled JuVenileS, 4–8 mm lOng (34–60 chaetigerS), 0.2–0.3 mm wide; 6 incOmplete Settled JuVenileS, up tO 10 mm lOng (38 chaetigerS), 0.2–0.4 mm wide.

EaStern BaSS Strait, 20 km SSW Of Babel ISland, TaSmania, RV 'TangarOa' CruiSe 81-T-1 StatiOn BSS 166, 40°06.8'S, 148°24.3'E, 22 m, cOarSe Shell, grab, 14 NOV 1981, cOll. R. WilSOn ( NMV F43627 : 1); EaStern BaSS Strait, 100 km NE Of NOrth POint, FlinderS ISland, RV 'TangarOa' CruiSe 81-T-1 StatiOn BSS 170 GSM, 31°51.8'S, 148°26.5'E, 130 m, fine Sand, grab, 15 NOV 1981, cOll. R. WilSOn ( NMV F43633 : 3); StatiOn BSS 170 SEB, Same data aS hOlOtype ( NMV F 240187: 2); 1WeStern BaSS Strait, 44 km SW Of Cape Otway, VictOria, RV 'TangarOa' CruiSe 81-T-1, StatiOn BSS 192, 39°06.3'S 142°55.6'E, 81 m, medium Sand, dredge, 21 NOV 1981, cOll. R. WilSOn ( NMV F43647 : 1); WeStern BaSS Strait, 70 km SW Of Cape Otway, VictOria, RV 'TangarOa' CruiSe 81-T-1, StatiOn BSS 194, 39°26.3'S, 143°06.8'E, 115 m, Sand, Sled, 21 NOV 1981, cOll R. WilSOn ( NMV F234213: 3).

Type locality. Pacific Ocean , EaStern BaSS Strait, 100 km NE Of NOrth POint, FlinderS ISland, 31°51.8'S, 148°26.5'E, 130 m, fine Sand.

Diagnosis. Antennae with 2–4 ceratOphOral ringS, StyleS tO chaetiger 6–10; 3 pairS Of mOdified parapOdia with mainly bidentate and few tridentate ShOrt- and lOng-appendaged pSeudOcOmpOund hOOkS, large Simple hOOkS abSent; limbate chaetae frOm chaetiger 3; SpinigerS frOm chaetiger 4 tO 9–11; Subacicular hOOkS frOm chaetiger 10– 12; aciculae with bulbOuS diStal end; branchiae abSent; fragile mucOuS tube.

Description. NO freShly fixed material aVailable; SpecimenS fixed in fOrmalin and preSerVed in ethanOl fOr almOSt 30 yearS cream cOlOured withOut any pigmentatiOn. AnteriOr end Of bOdy Slender, nearly cylindrical in pharyngeal regiOn, becOming brOader and Slightly depreSSed by chaetiger 5–6 ( Fig. 5A ). PrOStOmium wider than lOng, anteriOrly rOunded, with OVal, widely Separated frOntal lipS ( Fig. 5B ). TwO pairS Of eyeS ViSible Only On One paratype (NMV F43633 ), prObably bleached Out in Other SpecimenS: anteriOr pair Single SpOt between frOntal lipS and palpS, pOSteriOr pair made up Of 4 SpOtS each, preSent at baSe Of lateral antenna. PalpS and antennae with ShOrt ceratOphOreS with 2–3 (1–3) prOximal and lOnger diStal ring and gradually tapering StyleS. PalpOStyleS ShOrt, abOut 6–8 timeS aS lOng aS palpOphOre, tO chaetiger 1, antennOStyleS relatiVely lOng, lateral antennOStyleS tO chaetiger 8 (7–10), median tO 6 (6–7). Nuchal grOOVeS Straight with Small middOrSal SeparatiOn. PeriStOmium ShOrt, abOut half aS lOng aS chaetiger 1 ( Fig. 5B ). PeriStOmial cirri inSerted diStally On periStOmium On inner Side Of lateral antennae.

AnteriOr 3 chaetigerS and parapOdia hardly any lOnger than thOSe fOllOwing. FirSt 3 pairS Of parapOdia mOdified, directed Slightly anterOVentrally tO -laterally ( Fig. 5C ) with cuff-like prechaetal fOld, rOunded acicular lObe and Subulate pOStchaetal lObe ( Fig. 6A, B ). POStchaetal lObe becOming SucceSSiVely ShOrter, reduced tO Small knOb by chaetiger 10, abSent by chaetiger 15. DOrSal cirri initially Subulate ( Fig. 6A–C ), becOming Smaller and digitifOrm pOSteriOrly; Ventral cirri Subulate tO digitate On anteriOr 3 chaetigerS, replaced by glandular padS frOm chaetiger 4 ( Fig. 6C ). Branchiae abSent.

Aciculae initially diStally tapering ( Fig. 6A, B ), becOming SubdiStally bulbOuS by chaetiger 4 ( Fig. 6C ). Mainly bidentate pSeudOcOmpOund hOOkS with ShOrt hOOdS ( Fig. 6D, E ) preSent On anteriOr 3 chaetigerS. DiStal tOOth large and falcate; rarely 1 Or 2 tridentate hOOkS with tiny third tOOth ( Fig. 6F ) preSent. HOOkS cOnSiSting Of 2–3 Slender, lOng-appendaged ( Fig. 6D ) and 1–2 thicker, ShOrt-appendaged ( Fig. 6E ) OneS; median hOOk Of chaetiger 3 thicker, with ShOrter appendage and hOOd with Small SerratiOnS ( Fig. 6G ); large Simple median hOOkS abSent. Limbate chaetae abSent frOm chaetiger 1 and 2, Starting aS lOng upper limbateS On chaetiger 3 ( Fig. 6B ), ShOrt inferiOr limbateS and 2 (2–4) SpinigerS frOm chaetiger 4 ( Fig. 6C, H ), replacing pSeudOcOmpOund hOOkS; pSeudOcOmpOund hOOkS in turn replaced by 2 hOOded bidentate Subacicular hOOkS frOm chaetiger 12 (10–11). Pectinate chaetae apparently abSent, aS careful Scanning Of all type SpecimenS and additiOnal material On SlideS did nOt reVeal any.

Pygidium (ObSerVed in nOn-type JuVenileS) with twO pairS Of thin anal cirri; dOrSal pair reaching tO 3rd laSt chaetiger when fOlded back, Ventral pair aS lOng aS pygidium. MandibleS and maxillae extremely Small and fragile, nOt clearly ViSible. NO type SpecimenS cOllected with tube. HOweVer, One JuVenile ( NMV F43627 ) in a fragile mucOuS tube frOm Opening Of Small gaStrOpOd, reSembling Structure Of M. ariasi n. sp. tubeS.

Remarks. Mooreonuphis wilsoni n. sp., like M. ariasi n. sp., iS abranchiate and ShareS with M. intermedia , M. stigmatis and M. veleronis haVing Only three anteriOr chaetigerS with pSeudOcOmpOund hOOkS. HOweVer, theSe pSeudOcOmpOund hOOkS are tridentate in the three latter SpecieS, whilSt they are mainly bidentate in M. wilsoni n. sp.. Bi- and tridentate pSeudOcOmpOund hOOkS Occur in M. dangriae ( Fauchald, 1980) , M. guadalupensis Fauchald, 1968 and M. bidentata . HOweVer, M. wilsoni n. sp. iS unique in haVing mainly bidentate OneS with Only One Or twO hOOkS per parapOdium with a tiny third tOOth. Median large Simple hOOkS, preSent in M. stigmatis and M. veleronis , are abSent in M. wilsoni n. sp.; aciculae Of anteriOr unmOdified chaetigerS are diStally expanded in M. wilsoni n. sp. and M. veleronis but are tapered in M. intermedia and M. stigmatis . DifferenceS between the twO AuStralian SpecieS with reSpect tO their prOStOmial featureS, length Of antennae and number and diStributiOn Of chaetae are detailed in Table 1.

Etymology. It iS a pleaSure tO dedicate thiS SpecieS tO RObin WilSOn, whO cOllected the SpecimenS during the BaSS Strait SurVey by the MuSeumS VictOria.

Biology. The material frOm twO StatiOnS included Settled JuVenile SpecimenS, meaSuring 0.2–0.4 mm in width. They were claSSified aS JuVenileS Since they pOSSeSSed Only twO chaetigerS with pSeudOcOmpOund hOOkS. Their SpinigerS Start On chaetiger 3 inStead Of 4, and Subacicular hOOkS On chaetiger 9–10 inStead Of 10–12 aS in adultS. Other JuVenile featureS are the preSence Of anteriOr and pOSteriOr prOViSiOnal Subacicular hOOkS, whilSt head appendageS are aS in adultS.

Habitat and distribution. Mooreonuphis wilsoni n. sp. waS cOllected in BaSS Strait and Off Freycinet PeninSula, eaStern TaSmania, in 22–194 m in fine tO cOarSe Sandy SedimentS.

Figures

FIGURE 5. Scanning electron micrographs of Mooreonuphis wilsoni n. sp. (Paratype NMV F240186). A. Anterior part, dorsal vieW; B. same, enlarged vieW; C. anterior part, ventral vieW.

FIGURE 6. Line draWings of Mooreonuphis wilsoni n. sp. (Paratype NMV F240185). A, Parapodium 1, anterior vieW; B. parapodium 3, anterior vieW; C. parapodium 4, anterior vieW; D, long-appendaged bidentate pseudocompound hook of parapodium 1; E, short-appendaged median thicker pseudocompound hook of same; F, short-appendaged loWer pseudocompound hook With tiny third tooth of same; G, short-appendaged thick pseudocompound hook With small serrations on hood of chaetiger 3; H, spiniger of chaetiger 4.