Mooreonuphis ariasi, Paxton, 2018

Paxton, Hannelore, 2018, Two new species of Mooreonuphis (Annelida: Onuphidae) from Australia, Zootaxa 4486 (4), pp. 589-600 : 590-595

publication ID	https://doi.org/ 10.11646/zootaxa.4486.4.11
publication LSID	lsid:zoobank.org:pub:6E46C0C6-0F97-4C83-B293-D61C0923B96B
DOI	https://doi.org/10.5281/zenodo.5979796
persistent identifier	https://treatment.plazi.org/id/023F830B-FFAB-6F22-A6AC-FA7B805BFA45
treatment provided by	Plazi
scientific name	Mooreonuphis ariasi
status	sp. nov.

Treatment

Mooreonuphis ariasi View in CoL n. sp.

FigureS 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 ; Table 1

Material examined. Holotype: COmplete brOOding adult, 16 mm lOng (70 chaetigerS), 0.6 mm wide; New SOuth WaleS, Cape BankS: 34°00'S, 151°16.00'E, 45–50 m, 0 3 Jan–18 Jan 1991, Sta. 4-362 (AM W.50682). GoogleMaps

Paratypes: 45 cOmplete SpecimenS [Settled JuVenileS and adultS], 2–20 mm lOng (21–80 chaetigerS), 0.2–0.8 mm wide and 27 incOmplete SpecimenS up tO 0.3–0.8 mm wide.

Cape Banks: 34°00'S, 151°16.00'E, 45–50 m, 0 3 Jan–18 Jan 1991, Sta. 4-362 (AM W.50683:1 brOOding adult); Same data (AM W.50684: 2 brOOding adultS); Same data ( NMV F247145: 10 [including 3 brOOding adultS]); Cobblers , Bate Bay GoogleMaps : 34°06.8'S, 151°11.00'E, 35–40 m, 24 Jan 1990, Sta. C 21 (AM W.24206: 10 [including 1 On SEM Stub]) GoogleMaps ; 34°05.9'S, 151°12.00'E, 25–30 m, 24 Jan 1990, Sta. C7 (AM W.24208: 28 [including 3 SEM StubS]). 34°04.6'S, 151°13.00'E, 25–30 m, 25 Jun–26 Jul 1990, Sta. C37 (AM W.24216: 4).

Bass Point: 34°36'S, 150°54'E, 25–30 m, 29 Oct–14 NOV 1990, Sta. 3-8 (AM W.24217: 17 [including 2 On SEM Stub]).

Additional material examined: 46 cOmplete SpecimenS [JuVenileS and adultS], 2–10 mm lOng (21–60 chaetigerS), 0.25–0.8 mm wide and 20 incOmplete SpecimenS up tO 9 mm (50 chaetigerS), 0.25–0.7 wide.

Cape Banks: Sta. 4-348 (AM W. 24214: 2); 3-179 (AM W.24218: 24).

Cobblers, Bate Bay: Sta. C9 (AM W.24207: 6); Sta. C11 (AM W.24209: 9); Sta. C60 (AM W.24210: 2); Sta. C61 (AM W.24211: 4); Sta. C43 (AM W.24212: 2); Sta. 4-325 (AM W.24213: 1); Sta. 4-306 (AM W.24219: 15).

Wattamolla, off Providential Head: Sta. 3-67 (AM W.24215: 1).

Type locality. Pacific Ocean , Off Cape BankS, New SOuth WaleS, 34°00'S, 151°16.00'E, depth 45–50 m. GoogleMaps

Diagnosis. Antennae with 2–4 ceratOphOral ringS, StyleS tO chaetiger 3–5; 3 pairS Of mOdified parapOdia with tridentate ShOrt- and lOng-appendaged pSeudOcOmpOund hOOkS, large Simple hOOkS abSent; limbate chaetae frOm chaetiger 4; SpinigerS frOm chaetiger 4–9; Subacicular hOOkS frOm chaetiger 10; aciculae with tapering diStal endS; branchiae abSent; tube cOVered with Sand grainS, Often extending frOm mOlluSc ShellS.

Description. NO freShly fixed material aVailable; SpecimenS fixed in fOrmalin and preSerVed in ethanOl fOr 20+ yearS cream cOlOured withOut any pigmentatiOn. AnteriOr end Of bOdy Slender, nearly cylindrical in pharyngeal regiOn, becOming brOader and Slightly depreSSed after abOut chaetiger 10 ( Fig. 1 View FIGURE 1 , 2 View FIGURE 2 ). PrOStOmium wider than lOng, anteriOrly Slightly extended, with OVOid frOntal lipS clOSe tOgether ( Fig. 3A View FIGURE 3 ). HOlOtype and mOSt paratypeS with 2 pairS Of eyeS; anteriOr pair Single SpOt between frOntal lipS and palpS, pOSteriOr pair cOnSiSting Of SeVeral SpOtS at baSe Of lateral antennae. PalpS and antennae relatiVely ShOrt; ceratOphOreS with 2 (1–3) prOximal ringS and lOnger diStal ring, gradually tapering StyleS; palpOStyle abOut 4–5 timeS aS lOng aS palpOphOre, reaching tO chaetiger 1 (periStOmium–chaetiger 1); lateral antennOStyleS tO chaetiger 5 (3–5), median antennOStyleS tO 4 (3–4). Nuchal grOOVeS Straight with Small middOrSal SeparatiOn. PeriStOmium Very ShOrt, cOntracted intO firSt chaetiger, ViSible periStOmium generally leSS than half length Of chaetiger 1 ( Fig. 2C View FIGURE 2 ). PeriStOmial cirri Very ShOrt, inSerted diStally On periStOmium On inner Side Of lateral antennae ( Fig. 2C View FIGURE 2 ).

AnteriOr 3 chaetigerS and parapOdia Slightly lOnger than thOSe fOllOwing. FirSt 3 pairS Of parapOdia mOdified, directed anterOVentrally tO -laterally ( Fig. 2C View FIGURE 2 , 3A View FIGURE 3 ) with cuff-like prechaetal fOld, rOunded acicular lObe and Subulate pOStchaetal lObe ( Fig. 3B View FIGURE 3 ). POStchaetal lObe becOming SucceSSiVely ShOrter, reduced tO Small knOb by chaetiger 9–10, abSent frOm 12–13. DOrSal cirri initially Subulate ( Fig. 4A–C View FIGURE 4 ), becOming Smaller and digitifOrm pOSteriOrly; Ventral cirri Subulate tO digitate On anteriOr 3 chaetigerS, replaced by glandular padS frOm chaetiger 4 ( Fig. 4C View FIGURE 4 ). Branchiae abSent.

Aciculae with tapering diStal endS, 2–3 per parapOdium ( Fig. 4A–D View FIGURE 4 ). FirSt 3 chaetigerS with 2–3 lOngappendaged tridentate pSeudOcOmpOund hOOkS with Very Small third tOOth ( Fig. 4E View FIGURE 4 ), 2–3 ShOrt-appendaged tridentate pSeudOcOmpOund hOOkS ( Fig. 4F View FIGURE 4 ) and a median Slightly thicker hOOk with ShOrter appendage ( Fig. 4G View FIGURE 4 ). Large Simple median hOOkS abSent. FrOm chaetiger 4 tO chaetiger 9 Simple limbate chaetae and 1–2 cOmpOund SpinigerS ( Fig. 4H View FIGURE 4 ) replacing pSeudOcOmpOund hOOkS. Pectinate chaetae Slightly Oblique ( Fig. 4I View FIGURE 4 ) frOm chaetiger 9 Or later, with 8–10 lOng teeth. Subacicular hOOkS replacing SpinigerS and lOwer limbate chaetae cOnSiStently frOm chaetiger 10 ( Fig. 4D View FIGURE 4 ).

Pygidium with twO pairS Of thin anal cirri; dOrSal pair reaching tO 6th laSt chaetiger when fOlded back, Ventral pair aS lOng aS pygidium. MandibleS and maxillae ( Fig. 4J View FIGURE 4 ) Very fragile and tranSlucent, hardly SclerOtiSed at all; maxillary fOrmula: Mx I = 1 + 1; MII = 9 + 9; MIII = 9 + 0; MIV = 7 + 10; MV = 1 + 1. TubeS ( Fig. 1 View FIGURE 1 ) cOnSiSting Of Very fragile mucOuS layer, with attached Sand grainS and Small Shell fragmentS. WOrmS Often buried intO Small Snail Or biValVe ShellS, with anteriOr end extending frOm their OpeningS ( Fig. 2A, B View FIGURE 2 ).

Remarks. Mooreonuphis ariasi n. sp. and M. wilsoni n. sp., deScribed belOw, are amOng the SmalleSt repreSentatiVeS Of the genuS, the Only knOwn SpecieS that are abranchiate and where, tOgether with M. veleronis ( Fauchald, 1980) , the Subacicular hOOkS Of adultS cOmmence On chaetiger 10. They haVe Only three anteriOr chaetigerS with pSeudOcOmpOund hOOkS, a cOnditiOn that iS Shared by three Other SpecieS: M. intermedia ( Kinberg, 1865) , M. stigmatis ( Treadwell, 1922) and M. veleronis . Mooreonuphis ariasi n. sp. further reSembleS theSe three SpecieS in that itS pSeudOcOmpOund hOOkS are tridentate. HOweVer, median large Simple hOOkS, preSent in M. stigmatis and M. veleronis , are abSent in M. ariasi n. sp. The twO AuStralian SpecieS differ frOm each Other in a number Of featureS with reSpect tO their prOStOmial featureS, length Of antennae and number and diStributiOn Of chaetae which are detailed in Table 1.

Etymology. It giVeS me great pleaSure tO dedicate thiS SpecieS tO AndréS AriaS, cOlleague and friend.

Biology. A large number Of Mooreonuphis ariasi n. sp. SpecimenS frOm the Summer cOllectiOnS were brOOding in their tubeS ( Fig. 1 View FIGURE 1 ). The new SpecieS iS an aSynchrOnOuS brOOder, carrying One tO twO batcheS Of cOelOmic eggS and up tO Six batcheS Of embryOS/JuVenileS in indiVidual brOOd chamberS undergOing direct deVelOpment. Such a batch cOnSiStS Of three tO fiVe indiVidualS at the Same Stage Of deVelOpment. The eggS are Very large fOr the Small Size Of the adult wOrmS. One 17 mm (70 chaetigerS) cOmplete paratype (AM W.24217) carried fiVe large eggS Of OVate Shape in the cOelOm Of chaetigerS 29–34 and three Smaller OneS in chaetigerS 35–36 that meaSured 500 and 250 µm reSpectiVely at their lOng axiS. BatcheS Of embryOS/JuVenileS are enclOSed in Very thinly lined brOOd chamberS with the indiVidualS Of each chamber at the Same Stage Of deVelOpment. ThuS, an adult wOrm can harbOur fiVe tO Six chamberS with a tOtal Of 30 Or mOre OffSpring ranging frOm embryOS tO 23-chaetiger JuVenileS.

The hOlOtype (AM W.50682) and paratype (AM W.50683) were brOOding adultS inhabiting empty biValVeS. RemOVal Of the cOVeringS allOwed inSpectiOn Of the wOrmS and their brOOd chamberS ( Fig. 1 View FIGURE 1 ). BOth adultS were curled arOund their brOOdS; the hOlOtype had Six brOOd chamberS cOntaining embryOS and JuVenileS ranging frOm 5- chaetigerS tO 21-chaetigerS ( Fig. 1A View FIGURE 1 ), while the paratype carried cOelOmic eggS and fiVe brOOd chamberS ranging frOm embryOS tO 19-chaetiger JuVenileS ( Fig.1B View FIGURE 1 ). In anOther brOOding Specimen (AM W.24209) the beSt deVelOped JuVenileS Still in brOOd chamberS cOnSiSted Of 23 chaetigerS with a fully fOrmed gut, ObViOuSly ready tO leaVe the parental tube. They exhibited already Such adult characteriSticS aS fully deVelOped head appendageS, three anteriOr chaetigerS with pSeudOcOmpOund hOOkS and adult Subacicular hOOkS frOm chaetiger 10. Their Only JuVenile chaetae were anteriOr prOViSiOnal Subacicular hOOkS frOm chaetiger 3–10. The SmalleSt Settled JuVenile in a fragile mucOuS tube meaSured 2 mm in length, 0.25 mm in width and cOnSiSted Of 21 chaetigerS (AM W.24218).

Habitat and distribution. The new SpecieS iS cOmmOn Off Sydney , New SOuth WaleS, in Sandy / Shelly SedimentS in depthS Of 25–50 m.