Marphysa moribidii Idris, Hutchings and Arshad, 2014

Idris, Izwandy, Hutchings, Pat & Arshad, Aziz, 2014, Description of a new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicidae) from the west coast of Peninsular Malaysia and comparisons with species from Marphysa Group A from the Indo-West Pacific and Indian Ocean, Memoirs of Museum Victoria 71, pp. 109-121 : 110-115

Marphysa moribidii Idris, Hutchings and Arshad sp. nov.

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C693255A-0A15-4162-B9D2-B4EFAFD0C341

Figures 2 , 3 , 4 Material examined. Holotype. AM W43731 – male, complete, Pantai Kelanang, Morib, Selangor, 2.75827ºN 101.4379ºE, coll. I. Idris 19 Jul 2012.

Paratypes. AM W38690 – 2 specs (1 male and 1 female) , AM W38691 – 1 female , AM W38692 – 1 female , NTM W024777 – 1 spec. Data same as holotype.

Other material examined: AM W38684 – 1 female complete , NTM W024778 – 1 spec., Sg. Merbuk tributary, 5.6392ºN 100.4138ºE (range 10 km), coll. local bait digger 9 Feb 2011 ; AM W38685 – 2 females , NTM W024776 – 1 spec., Kg. Terubong Laut, Larut , Perak, 4.5659ºN 100.6557ºE (range 2 km), coll. local bait digger 8 Feb 2011 ; AM W38686 – 1 male, Kuala Gula , Perak, 4.9285ºN 100.5086º'E (range 5 km), coll. local bait digger 11 Feb. 2011 ; AM W38689 – 1 male, Tg. Kupang (2nd link bridge), Johore, 1.3956ºN 103.6221ºE, coll. I. Idris 5 Nov 2010 ; AM W38693 – 2 males, Kg. Sitiawan, Lumut , Perak, 4.2498ºN 100.6893ºE, coll. local bait digger 8 Feb 2011 ; AM W38694 – 1 male , NTM W024775 – 1 spec., Bt. 4, Port Dickson , Negeri Sembilan, 2.5034°N 101.8352ºE (range 2 km), coll. local bait digger 20 Jan 2011 ; AM W38695 – 1 female , NTM W024774 – 1 spec., Kuala Lukut , Negeri Sembilan, 2.5698ºN 101.7945ºE, coll. local bait digger 20 Jan 2011 .

Comparative material examined. Eunice mossambica ZMB 4005 Lectotype – female, Mozambique, coll. and det. Peters 1854; Marphysa mossambica AM W 35469 – female, Dumangas , Iloilo, Philippines, 10.7968ºN 122.6695ºE, coll. J. Monteros-Recente 7 May 2010, det. C.J. Glasby.

Measurement. Holotype. Mature male (with gametes visible through body wall in parapodia on anterior and mid body segments), complete specimen total length of 333 mm in preserved solution (70% ethanol). Body width at chaetiger 10 (with parapodia) 9.76 mm, total number of segments 465. Paratypes mostly incomplete, body width at chaetiger 10 (with parapodia) 4.8 – 8.0 mm. Longest preserved specimen is AM W38684, with total length of 612 mm and 780 segments.

Description. Holotype (paratype values in parentheses). Body long and slender. Cylindrical at anteriormost part of metastomium until chaetiger 7 (3 – 7) but gradually becoming flattened dorsoventrally towards posterior end. Live worm with blood red branchiae. Anterior metastomium dark red gradually became lighter, slightly transparent towards posterior allowing the alimentary canal to be seen. Preserved specimen olive green with white spots dorsoventrally distributed on anterior; continue mid-dorsally along metastomium to about one-quarter of the body length (figs. 2A and B). White spots visible on live specimen, but faint and not detected on some specimens if the worm was not completely cleaned of adhering sediment.

Prostomium consists of semi-circular, bilobed upper lips with distinct middle notch, appearing as if two lobes present (fig. 2B). Prostomium surface and appendages with almost smooth surface, without articulations. Prostomium appendages slightly curved. Median antenna about the same length as lateral antennae and slightly longer than palps (0.2 – 0.5 times longer). Antennae (median and lateral) about twice the length of the prostomium. Ceratophores and palpophores present, cylindrical, short, with no articulations (fig. 2B). No gap between palps and lateral antennae, but small gaps exist between median and lateral antennae. Eyes absent. Peristomium consists of two rings with length of first ring about 2.5 times longer than second ring. Dorsal part of first ring slightly longer than ventral side including peristomium fold. Lateral and ventral sides of first peristomium ring (lateral and lower lips) covered with abundant folds (fig. 2A). Mandibles dark brown but with white calcified layer on cutting plates (paratype: transparent cutting plates). Cutting plate suboval, flat, no dentition on cutting edge, slightly rough surface with carrier almost parallel (fig. 2C). Maxillae dark brown but becoming paler on edge (fig. 2D). Dental formulae: MxI = 1 + 1, MxII = 4 + 4 (4 + 5 – 6), MxIII = 6 + 0 (8 + 0), MxIV = 4 + 8 (7 + 8) and MxV = 1 + 1 (1 + 1). MxVI is absent.

Parapodia consisting of notopodial and neuropodial cirri, as well as post-chaetal lobe. Pre-chaetal lobe absent (fig. 3A). Notopodial cirri gradually change from subulate to conical towards posterior parapodia. Neuropodia initially with conical cirri gradually becoming sub-conical towards posterior end. Base of notopodial cirri sub-ovulate in anterior chaetigers without inflation but gradually becoming circular in median and posterior chaetigers. Post-chaetal lobe sub-conical in first chaetiger, gradually becoming sub-triangular by chaetiger three, low and broad from chaetiger four to around chaetiger 130, then gradually decreasing in size from chaetiger 131 towards posterior end. Branchiae first emerge from base of dorsal cirri at chaetiger 35 (33 – 39) and disappear by last 20 chaetigers. Number of branchial filaments gradually increases from one to maximum 11 (6 – 14), filaments arranged as pectinate type in mid-body, number of filaments decreases to one filament on posterior segments (fig. 3D). Length of branchial stem shorter than neuropodial cirri by chaetiger 35 (33 – 39), the chaetiger on which branchiae first emerge. Branchial stem length then gradually increases until about 10 – 15 times longer than notopodial cirri by chaetiger 70, where maximum number of branchial filaments is reached (13 in type specimens, 14 in non-types).

Chaetae divided into two fascicles: supra-acicular and sub-acicular chaetae with aciculae located in middle (lateral view) (fig. 3A). Six types of chaetae present: thick limbate; slender capillary; symmetrical pectinate; asymmetrical pectinate with narrow shaft; asymmetrical pectinate chaetae with broad shaft; and wide pectinate chaetae with wide teeth (figs. 3B, C; figs. 4A, B, C). Limbate chaetae longer and thicker than capillaries but both serrated. Limbate and capillary chaetae present in both fascicles throughout body. Number of limbate chaetae range from 28 – 41 until about chaetiger 100 and then reducing to 13 – 19 chaetae in posterior region. Capillary chaetae present in small numbers (<10) throughout. Symmetrical pectinate chaetae characterized as having both outer teeth of the same length with slender shaft (fig. 3B; fig. 4A). Symmetrical pectinate chaetae present from chaetiger five (chaetiger three in paratype), apparently absent after chaetiger five until chaetiger 50, then present again from chaetiger 51 onwards. Asymmetrical pectinate chaetae only present from chaetiger 100 onwards in type specimens and characterised as having the outer teeth of different length to the median teeth with broad or narrow shafts (fig. 3C, figs. 4B, C). The wide-toothed pectinate chaetae with wide body are present in holotype from about chaetiger 400 onwards (figs. 4B, C). Numbers of pectinate chaetae per parapodia ranged from one to six for both holotype and paratypes. Aciculae 3 – 4 per parapodium, dark brown, distally pointed, and arranged straight and almost parallel between fascicles. No sub-acicular hooks in holotype; however in paratypes, bidentate hooks present from median chaetiger (chaetiger 71 in one paratype only), but occurring irregularly.

Pygidium typical of Marphysa species, two pairs of unequally sized pygidial cirri inserted ventrally, arranged on top of each other. Largest: dorsal, two times height of pygidium, smallest about one-quarter height of pygidium.

Etymology. The name ‘ moribidii ’ refers to the location (Morib mangrove) where the type specimens were collected. Morib is also the landing site of the 46 th Indian Beach Group under the Allied Forces to mark the end of the Japanese occupation of Malaya in 1945. The local name for Marphysa moribidii is ruat bakau (mangrove worm).

Intraspecific variation. Information on the morphological variation present in this species is based upon detailed examination of 914 specimens collected from the type locality from June 2011 to December 2012. However, of these, only 136 specimens were complete. The large number of incomplete specimens was due to the method of collecting by digging with a shovel and the fragility of the animals. Length of complete specimens in preserved 70% ethanol ranges from 7 – 477 mm, with the number of chaetigers varying from 113 – 580.However, there is an incomplete specimen with 600 chaetigers, indicating that the number of chaetigers can be higher or similar to the longest deposited specimen (AM W38684). Body colour varies from dark olive green to light brown. In some specimens, the white spots are absent. Peristomium flap on the anterior of first ring can extend until it covers the ceratophores and palpophores. However, in some specimens, the flap was not detected or was reduced.

The chaetiger number at which the branchiae commence varies greatly in non-type specimens. The branchiae begin from chaetiger 4 – 63 as a single filament (in some specimens two to three filaments) and can reach a maximum number of 14 filaments in non-type specimens. The distribution of bidentate, sub-acicular hooks is irregular; they are present from chaetiger 44 in some specimens (figs. 3E, 4D). Some specimens also possess two bidentate sub-acicular hooks at the midsection of the body (chaetigers 60 – 78).

The relationship between body width at chaetiger 10 and the chaetiger on which the branchiae appear (fig. 5A) shows a significant positive linear relationship (R 2 = 0.21; n = 35; p <0.05).

The positive relationship for these morphological characters is similar to that found in M. cf. mossambica and occurring in the synonymised M. novaehollandiae ( Glasby and Hutchings, 2010) . However, the correlation value of M. moribidii and M. cf. mossambica differs significantly between the two species (z = 3.19, p <0.05).

Moreover, the relationship between body width and the chaetiger on which the sub-acicular hook appears (fig. 5B) is not statistically significant (R 2 = 0.05; n = 35; p> 0.05). Thus the appearance of sub-acicular hooks on the parapodia is not in a predictable pattern for M. moribidii sp.nov.

Figures

Figure 2. Marphysa moribidii sp. nov. [A] anterior section, lateral view. Note on the white spots on the epidermis of the specimen; [B], anterior section, dorsal view, showing the palpophore (I) and ceratophores (II); [C] mandible; [D] maxillae. [A, B, C] from non-type specimens; [D], from holotype (AM W43731). Mx = Maxillae. Scale bars: [A, B, C, D] = 1 mm.

Figure 3. Marphysa moribidiii sp. nov., [A] limbate and simple capillary chaetae, chaetiger 3; [B] symmetrical pectinate chaeta on the supraposition (arrow), chaetiger 50; [C] asymmetrical pectinate chaetae (arrow), chaetiger 10; [D] whole parapodium with branchia, showing relative length with notopodial cirrus, chaetiger 150; [E] sub-acicular hook (arrow), chaetiger 150. Brc = Branchia; Ntp = Notopodial cirrus; Neu = Neuropodial cirrus. [A, C, D, E] = Paratype, AM W38692; [B] = Non-type (AM W38687). Scale bars: [A, D, E] = 100 µm; [B, C] = 20 µm.

Figure 4. Marphysa moribidii sp. nov. [A] details of symmetrical pectinate chaetae, chaetiger 20; [B] wide pectinate chaeta with wide teeth (W-pct), dorsal view, chaetiger 400; [C] asymmetrical pectinate chaetae, all types, chaetiger 456; [D] (arrow) detail of bidentate sub-acicular hook, chaetiger 98. Asym-bd = asymmetrical pectinate with broad shaft; Asym-ns = asymmetrical pectinate with narrow shaft; [A] = non-type (AM W38687); [B, C] = holotype (AM W43731), [D] = non-type specimen. Scale bars: [A] = 3 µm; [B, C, D] = 20 µm.