﻿Four new species of Marphysa (Annelida, Eunicida, Eunicidae) from the east coast of Peninsular Malaysia

﻿Abstract Four new species of Marphysa are described from Terengganu state on the east coast of Peninsular Malaysia, using morphological and molecular (cytochrome oxidase subunit I (COI) gene) data. These species belong to different groups of Marphysa: Marphysakertehensissp. nov. belongs to Group A (Mossambica), Marphysamerchangensissp. nov. and Marphysasetiuensesp. nov. belong to Group B (Sanguinea) and Marphysaibaiensissp. nov. belongs to Group E (Gravelyi). Marphysakertehensissp. nov. is characterised by having only limbate chaetae, absence of subacicular hooks, three types of pectinate chaetae including wide, thick isodont with short and slender inner teeth, and pectinate branchiae with up to nine branchial filaments. Marphysamerchangensissp. nov. is characterised by the presence of eyes, unidentate subacicular hooks, four types of pectinate chaetae including wide, thick anodont pectinate chaetae with five long and thick inner teeth, and pectinate branchiae with up to six branchial filaments. Marphysasetiuensesp. nov. has mostly unidentate subacicular hooks (bidentate on several posterior chaetigers), four types of pectinate chaetae including wide, thick anodont pectinate chaetae with seven thick and long inner teeth, and pectinate branchiae with up to five branchial filaments. Marphysaibaiensissp. nov. has bidentate subacicular hooks throughout, five types of pectinate chaetae, including a heterodont with 12 short and slender inner teeth, and pectinate branchiae with up to eight branchial filaments. The designation of these new species based on morphology is fully supported by molecular data. Habitat descriptions of each species are also included.


Introduction
Marphysa de Quatrefages 1866, currently with 83 accepted species, is the second most speciose genus in the family Eunicidae, after the genus Eunice Cuvier, 1817 (Read and Fauchald 2023).Marphysa species inhabit a wide range of habitats, either in soft sediments or rocky ground, from intertidal to shallow subtidal depth, and are commonly found in estuarine or sheltered habitats (Abdullah et al. in review;Zanol et al. 2016;Martin et al. 2020).Three species have recently been described from the deep sea (Lavesque et al. 2023).Taxonomic studies of Marphysa species have increased considerably since the redescription of the type species, M. sanguinea (Montagu, 1813) and the designation of a neotype by Hutchings and Karageorgopoulos (2003); and later by molecular sequencing (Zanol et al. 2010).Since then, many more species have been described or previously synonymised species resurrected, using molecular data and additional morphological characters such as the types and distributions of chaetae.
According to Fauchald (1970) and Glasby and Hutchings (2010), Marphysa can be divided into five informal groups (Groups A-E) depending on their type of chaetae.Group A (Mossambica) without compound chaetae, Group B (Sanguinea) with only compound spinigers present, Group C (Aenea) with only compound falcigers present, Group D (Belli) with both spinigers and falcigers present, and Group E (Teretiuscula; renamed Gravelyi by Molina-Acevedo and Idris 2021) with only compound spinigers and subacicular chaetae in anterior parapodia and limbate chaetae throughout.
In Malaysia, Paxton and Chou (2000) suggested that the low number of polychaete species identified in Malaysia is an underestimate due to the limited sampling of polychaetes.Idris et al. (2014) described Marphysa moribidii Idris, Hutchings & Arshad, 2014 from the west coast of Peninsular Malaysia.The species is currently the only Marphysa described from Malaysia, occurring in Rhizophora and Sonneratia spp.mangroves.Marphysa moribidii is regularly used as fishing bait by local fishermen.In addition, recent studies (Ee Pei et al. 2020;Rapi et al. 2020;Rosman et al. 2020) reported the potential applications of M. moribidii as a wound-healing agent and bio-catalyst of gold and silver nanoparticles.This study investigated Marphysa species from the mangrove forest on the east coast of Peninsular Malaysia, specifically Terengganu, as they may also have potential applications similar to M. moribidii.We found four new Marphysa species using an integrated approach to taxonomy, including morphological and molecular analyses.

Study area and sampling
Marphysa specimens were collected from the rivers, lagoon and estuary of the Terengganu mangrove forests during spring low tides from September 2021 until March 2022.A total of four mangrove areas were chosen, i.e.Setiu wetlands, Kuala Ibai, Merchang, and Kerteh (Fig. 1A, B).At each site, sediments were dug using a shovel to approximately 30 cm depth at several points along the river (upper course to lower course) and carefully broken into small pieces to search for the worms.Worms suspected to be Marphysa were fixed and preserved in 95% ethanol.Sediments where the Marphysa worms were found were also collected and kept in labelled plastic bags for sediment analysis.All material was collected by the first author.

Morphological analyses
Preserved specimens were examined under AmScope SM-2 Series stereo and 120 Series compound microscopes.Additionally, the specimens were also examined under Leica M165 C stereo and Nikon Labophot-2 compound microscopes, and photographed with a Nikon D610 camera at the Natural History Museum of Los Angeles County, USA (NHMLAC).Drawings of parapodia and pectinate chaetae were made using a Wacom Intuos Pro drawing tablet.Length at chaetiger 10 (L10) and width at chaetiger 10 (W10) without parapodia of all specimens were measured and recorded.Morphological terminology, including diagnostic features of Marphysa species, follows Molina-Acevedo and Carrera-Parra (2017).Terminology of pectinate chaetae is derived and modified from Carrera-Parra and Salazar-Vallejo (1998) for the relative length of outer and inner teeth, Zanol et al. (2014Zanol et al. ( , 2016) ) for the thickness of the blade and Glasby et al. (2019) for the size of the inner teeth: isodont means outer teeth much longer than inner teeth; anodont means outer teeth more or less the same length as inner teeth; heterodont refers to when one long and one short (same length as inner teeth) lateral tooth is present.The thickness of the shaft is thin when it is thinner than the limbate chaetae on the same parapodium, thick when the shaft is as thick or thicker than limbate chaetae on the same parapodium.The width of the pectinate blade is wide when the blade is ≥ 30 μm and narrow below this threshold; length of the inner teeth is long when they are ≥ 12 µm and thick when ≥ 2 µm; below these thresholds, the teeth are defined as short and slender, respectively.Table 1 and Fig. 2 summarises and illustrates the types of pectinate chaetae present in species of Marphysa from Terengganu.
Terminology of maxillary apparatus followed Molina-Acevedo and Carrera-Parra (2015).Several parapodia from the anterior, median, and posterior regions were removed from the type material of each species, dehydrated in ethanol and hexamethyldisilazane (HMDS), coated with 20 nm of silver-gold, examined under the scanning electron microscope JEOL JSM-6360LA, and imaged with a secondary detector at SEM laboratories of Universiti Malaysia Terengganu and Macquarie University, Sydney, Australia.

Repositories
Materials were deposited at the institution and museums listed below:
A total of 63 COI sequences were downloaded from GenBank or obtained during this study; 60 COI sequences of Marphysa species and three outgroup species from closely related genera in the order Eunicida (Table 2).All COI sequences were aligned in MEGA v. 11.0.10 using ClustalW plugin with default settings.The best DNA/Protein Models (ML) test was conducted, and the GTR model of molecular evolution was chosen as the best evolutionary model for the COI gene alignment.The phylogenetic analysis was performed in MEGA v. 11.0.10 (Tamura et al. 2021).The analysis was run for 1000 replicates.Pair-wise Kimura 2-parameter (K2P) genetic distance was performed using MEGA v. 11.0.10.

Habitat description and sediment analyses
Habitats of identified Marphysa were described based on the observations made during sampling including mangrove vegetations and sediment analyses.The particle size of the sediments was determined using dry-sieving techniques.Sediments were oven-dried at 60 °C for ~ 72 h.Then, 100 g of sub-samples were gently dry-sieved through a series of 4, 2, 1, 0.5, 0.25, 0.125, and 0.063 mm mesh openings of an Octagon D200 Digital mechanical shaker.Sediments retained on each sieve were weighed and recorded.Sediment grain size was classified according to grain size classifications by Blair and McPherson (1999), modified after Udden (1914) and Wentworth (1922).The percentage of particle size compositions was calculated, and the texture of sediments was determined based on the sediment textural classification scheme of Blair and McPherson (1999), modified after Folk et al. (1970).Furthermore, total organic matter was determined using the loss on ignition (LOI) method which calculates the weight loss after combustion (Dean 1974).A total of 5 g of oven-dried sediments were placed in ceramic crucibles and ashed at 550 °C for six h in a muffle furnace.Then, sediments were cooled in a desiccator and weighed.The percentage of total organic matter (TOM) was analysed by the percentage loss of weight on ignition at 550 °C.

Molecular analyses
DNA sequences of COI (460 bp) (Fig. 3) were used for phylogenetic analysis based on the maximum likelihood (ML) method.Results based on the COI showed that the four Marphysa species from Terengganu were well separated from other sequences of Marphysa and formed four different clades.Nodal support ranges from 97-100%, showing strong support for the clades.The interspecific divergence between these new species and all their sister taxa pair is high (pair-wise Kimura 2-parameter -COI K2P range from 6.14%-19.16%)(see Suppl.material 1).

Ecological analyses
Particle size analyses of sediment from sampling sites in Terengganu mangrove forest estuary, lagoon and river are shown in Table 3.Generally, sediments from all sampling sites were mainly composed of sand.However, sites can be differentiated by the composition of different particle sizes, sediment texture, and percentage of organic matter content.Sediments collected from Setiu Wetlands, Kuala Ibai mangrove estuary, and Kerteh mangrove river were dominated by fine sand; meanwhile, sediments from Merchang mangrove estuary and Kuala Ibai lagoon were dominated by a mixture of fine pebble + granule and medium size sand, respectively.

Taxonomic account
Prostomium bilobed, anteriorly rounded with two dorsoventrally flattened lobes separated by an anterior notch between (Fig. 5B).Prostomial appendages in a semicircle, median antennae separated by a gap (Fig. 5B).Palps reach to first ring of peristomium; lateral and median antennae to second ring of peristomium.Palpophores and ceratophores are ring-shaped, short, thin; palpostyles and ceratostyles tapering and slender.Prostomial peduncles absent.Peristomium larger and wider than prostomium; first ring 3× longer than second ring, separation between rings distinct on all sides.
Etymology.The new name denotes the type locality (Kerteh River) where the specimens were collected.
Remarks.With the presence of only limbate chaetae in both supra-and subacicular chaetae bundles, Marphysa kertehensis sp.nov.belongs to Marphysa Group A (Mossambica).Comparing Marphysa Group A from Malaysia's coastal water bodies, M. kertehensis sp.nov. is similar to M. moribidii (type locality: Morib, Malaysia) in lacking eyes.Table 5 lists the characteristics of Group A species, such as the presence or absence of peduncle in the prostomial appendages, the number of types of pectinate chaetae, chaetiger from where the branchiae commence and finish, number of branchial filaments and subacicular hooks and all differ from the new species.Marphysa kertehensis sp.nov.has three types of pectinate chaetae (types 1, 2, 4) but lacks any wide anodont chaetae (types 6, 7, 8), while M. moribidii has four types, including wide anodont (types 1, 4, 5, 8).Although they all have the same type of pectinate branchiae and the chaetiger where the branchiae emerge, M. moribidii (TL: 333 mm) has a wider range variation of chaetiger where the branchiae emerge; they occur from chaetiger 35 (4-63) whereas in M. kertehensis sp.nov.(TL: 413 (173-295) mm), the branchiae are present from chaetiger 41 (27-58).There are no subacicular hooks present in all specimens of M. kertehensis sp.nov., but there are Table 5. Morphological features comparison between Marphysa Group A (Mossambica) described in this study and species occurring within Malaysian water bodies.The features for new species are based on holotype, with variation in parentheses for paratypes.Abbreviations: MF: maxillary formula, roman numerals refer to number of maxilla; PR-I: first peristomial ring; PR-II: second peristomial ring; p/a: present/absent; NIA: no information available.The major feature's differences between the species are mark with asterisk (*).Maxillary apparatus with four pairs of maxillae, an unpaired on the left side, MI with falcal arch extended at sub-right angle, basal outer edge arched, basal inner edge lacking curvature.MII with triangular teeth and without attachment lamella.MIII slightly curved, with equal-sized triangular teeth, without attachment lamella.MIV with rectangular and curved attachment lamella.Branchiae distributed along entire body.Dorsal cirri without articulations; postchaetal lobe well developed in anterior regions.Ventral cirri with swollen, inflated base.Sub-aciculae black, blunt, and translucent at distal end, pale brown in posterior-most parapodia.Supra-acicular chaetae include limbate, pectinate thin, narrow isodont with short and slender inner teeth, pectinate thick, wide isodont with short or long and slender inner teeth, and pectinate thick, narrow and wide anodont with long and thick inner teeth.Subacicular chaetae include only compound spinigers.Subacicular hook unidentate throughout chaetigers.Pygidium with two pairs of anal cirri, without articulation.
Prostomium bilobed, anteriorly rounded with two dorsoventrally flattened lobes with an anterior notch between them (Fig. 8A, B).Prostomial appendages in a semicircle, median antenna isolated by a gap (Fig. 8B).Palps reach middle of second peristomial ring; lateral antennae reaching chaetiger 2; medi-an antenna reaching chaetiger 3. Palpophores and ceratophores ring-shaped, short, and thick; palpostyles and ceratostyles tapering, and slender.Prostomial appendage peduncles absent.A pair of faded brown eyes present at posterior base of prostomium, between palps and lateral antennae (Fig. 8B).Peristomium larger and wider than prostomium; first ring is 2.5× longer than second ring, separation between rings distinct on all sides.
Etymology.The name denotes the type locality (Merchang estuary) where the specimens were collected.Type locality.South China Sea, Malaysia, east coast of Peninsular, Terengganu, Merchang mangrove estuary (see Fig. 1).
Distribution.Known only from the type locality and Setiu Wetlands, Terengganu, Malaysia.
Finally, M. merchangensis sp.nov. is similar to M. orientalis by having unidentate subacicular hooks.Marphysa merchangensis sp.nov.has a pair of eyes and two pairs of anal cirri, while M. orientalis has no eyes and only one pair of anal cirri.Also, branchiae in M. merchangensis sp.nov.begin earlier from chaetiger 24 (16-27) compared to M. orientalis (chaetiger 45).The maximum number of branchial filaments in M. merchangensis sp.nov. is six, while M. orientalis has a maximum of three branchial filaments.Nevertheless, the original description of M. orientalis is incomplete and does not include certain important features such as the number and type of pectinate chaetae.Fresh material of M. orientalis should be collected and redescribed from the type locality at Gulf of Mannar, Sri Lanka.Maxillary apparatus with four pairs of maxillae, an unpaired on the left side, MI with falcal arch extended at sub-right angle, basal outer edge arched, basal inner edge lacking curvature.MII with triangular teeth and without attachment lamella.MIII slightly curved, with equal-sized triangular teeth, without attachment lamella, MIV with curved attachment lamella.Branchiae distributed along entire body.Dorsal cirri without articulations; postchaetal lobe well developed in anterior regions.Ventral cirri with swollen, inflated base.Sub-aciculae black, blunt, and translucent at distal end, pale brown in posterior-most parapodia.Supra-acicular chaetae include limbate, pectinate thin, narrow and wide isodont with short and slender inner teeth, and pectinate thick, wide anodont with long and slender or thick inner teeth.Subacicular chaetae include only compound spinigers.Subacicular hook unidentate, and a few bidentate present in posterior chaetigers.Pygidium with two pairs of anal cirri, without articulation.
Prostomium bilobed, anteriorly rounded with two dorsoventrally flattened lobes separated by an anterior notch (Fig. 11A, B).Prostomial appendages in a semicircle, median antenna isolated by a gap (Fig. 11B).Palps reaching chaetiger 3; lateral antennae reaching chaetiger 4; median antenna reaching chaetiger 5. Palpophores and ceratophores ring-shaped, short, and thick; palpostyles and ceratostyles tapering and slender.Prostomial appendage peduncles absent.Pair of faded brown eyes at posterior base of prostomium, between palps and lateral antennae.Peristomium similar in size (width and length) to prostomium; the first ring is 1.5× longer than second ring, and separation between rings distinct on all sides.
First parapodia occur ventrolaterally, gradually becoming dorsolateral in following segments.Chaetal lobes rounded in all chaetigers (Fig. 11G-I).Prechaetal lobe shorter than chaetal lobe along whole body.Postchaetal lobe digitiform in first three chaetigers and rounded thereafter; conical and longer than chaetal lobe in median and posterior chaetigers, becoming shorter and absent in the posterior-most chaetigers.Dorsal cirri thumb-shaped with digitiform tips, shorter than ventral cirri in anterior, digitiform with slender and tapering tips; slightly longer or similar length from mid-body onwards and shorter in posterior-most chaetigers (Fig. 11G-I).Ventral cirri thumb-shaped with digitiform tips in the first few chaetigers, basally inflated with digitiform tip from chaetiger 15 onwards, and gradually becoming conical posteriorly (Fig. 11G-I).Branchiae pectinate, from chaetiger 20 (15-25) and continuing to near the end (~ 8 last chaetigers without branchiae), branchial filament 4× longer than dorsal cirri where best developed; number of filaments increasing from two anteriorly to five in mid-body, decreasing to one in last several chaetigers.
Distribution.Known only from the type locality.
Marphysa setiuense sp.nov.and M. orientalis differ by the presence or absence of eyes, shape of subacicular hooks, pair of anal cirri, the chaetiger on which the branchiae begin and the maximum number of branchial filaments.Marphysa setiuense sp.nov.has a pair of eyes and two pairs of anal cirri, while M. orientalis has no eyes and only one pair of anal cirri.The new species has unidentate and bidentate subacicular hooks while M. orientalis has only unidentate subacicular hooks.Branchiae in M. setiuense sp.nov.begin from chaetiger 20 (15-25) whereas in M. orientalis they occur from chaetiger 45.The maximum number of branchial filaments in M. setiuense sp.nov. is five, while M. orientalis only has three branchial filaments.
Prostomium conically bilobed, with two dorsoventrally lobes separated by an anterior notch (Fig. 14A, B).Prostomial appendages in a semicircle, median antennae separated by a gap.Palps, lateral and median antennae reaching first peristomium.Palpophores and ceratophores ring-shaped, short, and thin; palpostyles and ceratostyles tapering and slender.Prostomial appendage peduncles absent.Peristomium wider than prostomium; first ring 3× longer than second ring, separation between rings distinct on all sides.
First few parapodia inserted ventrolaterally, but then becoming lateral in anterior region and dorsolaterally in subsequent segments.Chaetal lobes rounded on all chaetigers (Fig. 14F-H).Prechaetal lobe shorter than chaetal lobe along the entire body.Postchaetal lobe rounded and longer than chaetal lobe in anterior chaetigers and mid-body onwards (Fig. 14F-H), becoming shorter and absent in the posterior-most chaetigers.Dorsal cirri digitiform and slender, longer than ventral cirri anteriorly, as long as or shorter from mid-body and shorter in posterior chaetigers (Fig. 14F-H).Ventral cirri digitiform in first chaetigers, basally inflated with digitiform tip from chaetiger six onwards (Fig. 14F-H).Branchiae pectinate, starting from chaetiger 20 (11-65) and continuing to near end (~ 13 last chaetigers without branchiae), branchial filament 3× longer than dorsal cirri where best developed; number of filaments increasing from one anteriorly to eight in mid-body, decreasing to six in last several chaetigers.Pygidial cirri attached to ventral side of pygidium, dorsal pair ~ 4× longer than ventral (Fig. 14I).
Etymology.Name refers to the type locality Kuala Ibai River.Type locality.South China Sea, Malaysia, east coast of Peninsular, Terengganu, Kuala Ibai river estuary and lagoon (see Fig. 1).
Distribution.Known only from the type locality.
Marphysa ibaiensis sp.nov.can be distinguished from M. borradailei by the number of branchial filaments, shape of the subacicular hooks, chaetiger where the branchiae and subacicular hook occur, and the shape of postchaetal lobe in the anterior region.Marphysa ibaiensis sp.nov.(TL: 52 (20-91) mm) has a maximum of eight branchial filaments whereas M. borradailei (TL: 1-8 mm) has up to 20 branchial filaments.The subacicular hook of M. ibaiensis sp.nov. is bidentate and occurs from chaetiger 22 (22-46) onwards while M. borradailei has a strongly hooded unidentate hook that occur from chaetiger 50 onwards.Marphysa ibaiensis sp.nov.has rounded postchaetal lobe in anterior region, while M. borradailei has sub-conical shaped postchaetal lobes in the anterior region.The original description of M. borradailei makes it challenging to undertake a detailed morphological comparison and additional material from the type locality (Sri Lanka) needs to be collected and redescribed.

Discussion
Prior to this study, a total of ten Marphysa species were described from Malaysia and nearby coastal waters (South China Sea and Andaman Sea) including one species from Group A (Mossambica) -Marphysa moribidii, six species from Group B (Sanguinea) -M.iloiloensis, M. hongkongensa, M. multipectinata, M. orientalis, M. tribranchiata, and M. tripectinata, one species from Group D (Belli) -M.digitibranchia Hoagland, 1920 (type locality: Hong Kong), and two species from Group E (Gravelyi) -M.madrasi and M. gravelyi.This study increases the number of Marphysa species from these water regions to 14.
Characteristics such as the distribution of different types of chaetae, including pectinate chaetae, branchial distribution and number of filaments, and jaw formula, allowed us to describe four new species.These characters have also been used recently by Lavesque et al. (2020) and Martin et al. (2020) in their studies of species of Marphysa.
All these new species occur in slightly different types of habitats, but share several general characteristics: all are found in mangrove areas, tolerate a wide range of salinity (euryhaline), and live in high percentage of sand.According to Glasby and Hutchings (2010), habitat type is a useful character to recognise species in a particular area.Therefore, describing a species' habitat is important for taxonomic studies and conservation strategy management.
Phylogenetic analysis from COI data placed M. merchangensis sp.nov.as sister to M. hongkongensa, M. setiuense sp.nov.as sister to M. iloiloensis, M. ibaiensis sp.nov.as sister to M. madrasi, and M. kertehensis sp.nov.as sister to M. mossambica (Peters, 1854).Nevertheless, the interspecific divergence between these new species and all their sister taxa pair is high (Pair-wise Kimura 2-parameter -COI K2P range 6.14%-19.16%(see Suppl.material 1), which clearly showed the distinct genetic separation.Additionally, obtaining sequence data for M. moribidii is imperative to investigate the genetic difference between M. moribidii and M. kertehensis sp.nov.as they possessed a few similar morphological features and occur within Malaysian water bodies.The molecular analysis in this study aligns with the morphological analysis and confirms the presence of four new Marphysa species in the Terengganu mangrove area.

Conclusions
Four species of Marphysa from Terengganu mangrove forests (lagoon, river, and estuary) were described and confirmed by morphology and molecular data and can also be separated based on their habitat.This study increases the species in the genus Marphysa and the number of polychaetes described from Malaysia.In addition, data provided in this study can also provide insight for future research on the potential use of Marphysa species in Malaysia as the only described species in Malaysia, M. moribidii has revealed a wide potential application for commercial use.ment, INOS, UMT) in the collection of type specimens of Marphysa species from Terengganu mangrove river, lagoon, and estuary.Also, we are very thankful for the assistance from INOS and South China Sea Repository and Reference (RRC) staff throughout the research journey and for all the facilities provided by Universiti Malaysia Terengganu.We extend our gratitude to Sue Lindsay from the Macquarie University for mounting the parapodia and taking the SEM photos of paratypes.We also would like to thank the Natural History of Los Angeles County (NHMLAC) for awarding the Anne Baker-Hayes Polychaete Student Fund to the first author.Our deepest gratitude goes to Ms Leslie Harris and Dr. Kirk Fitzhugh (Polychaete Department of NHMLAC) for providing facilities to photograph the type material, research experience and hospitality for the first author during her visit.Finally, our sincere appreciation goes to the Academic Editor (Chris Glasby) and two expert reviewers (you know who you are) for their meticulous comments and editing this manuscript.

Figure 1 .
Figure 1.Map showing sampling sites of four new Marphysa species in Terengganu mangrove forest, east coast of Peninsular Malaysia A location of Terengganu on the east of Peninsular Malaysia B symbols indicate each sampling site; Setiu Wetlands (red star), Kuala Ibai (red rhombus), Merchang (red triangle), and Kerteh (red oval).

Figure 3 .
Figure 3. Phylogenetic tree generated by maximum likelihood (ML) method based on COI (460 bp).The sequences of the four new species of Marphysa obtained in this study are marked in red.Numbers beside the branches indicate ML bootstrap values of 80 (maximum: 100) based on 1000 bootstrap replications.

Figure 7 .
Figure 7. Sampling site in Kerteh mangrove forest (river area) A habitat of Marphysa kertehensis sp.nov.B Marphysa kertehensis sp.nov.found inside driftwood and C in the sediment D live and complete M. kertehensis sp.nov.
), 1+1.Maxillary carrier ~ 2.5× shorter than MI, rectangular anteriorly, triangular posteriorly.MI forceps-like, without attachment lamellae, falcal arch extended at sub-right angle, basal outer edge arched, basal inner edge lacking a curvature.Closing system ~ 3× shorter than MI.Ligament between MI and MII pale brown.MII without attachment lamella, teeth triangular, distributed on < 1/2 length of the plate.Ligament between MII and MIII pale brown.MIII single, longer than left MIV slightly curved, with equal-sized triangular teeth, without attachment lamella.Left MIV short (< 1/2 the size of right MIV) with rectangular attachment lamellae.Right MIV long with curved attachment lamellae, teeth triangular, decreasing in size and teeth curved posteriorly.MV paired.Mandible pale brown, with concentric stripes, longer than MI; cutting plates whitish (Fig.8D).

Figure 10 .
Figure 10.Sampling site in Merchang mangrove estuary A habitat of M. merchangensis sp.nov.B-C worm found in decayed root of Exoecaria agallocha (Malay: Bebuta) D live worms.

Figure 16 .
Figure 16.Sampling site in Kuala Ibai (estuary and lagoon area) A habitat of Marphysa ibaiensis B found in sediment deposited inside driftwood C live M. ibaiensis sp.nov.

Table 1 .
Type of pectinate chaetae present in Marphysa from Terengganu.
The temperature profile was as follows: 95 °C / 180 s -(94 °C / 20 s -45 °C / 30 s -72 °C / 60 s)*35 cycles and final extension time at 72 °C / 300 s.PCR success was verified by electrophoresis in a 1% p/v agarose gel stained with GelRed.Amplified products were sent to Apical Scientific Sdn.Bhd.for Sanger sequencing using forward primer (LCO1490).Meanwhile, at AMRI, extractions of DNA were done with an ISOLATE II Genomic DNA kit (BIOLINE) following the protocol supplied by the manufacturers.

Table 3 .
Particle size composition (%) of sediments from four sampling sites in Terengganu mangrove forest.Asterisk (*) indicates the largest particle size composition.

Table 4 .
Distance of sampling sites from river mouth, type of sediment textures and total organic matter content of sampling sites in Terengganu mangrove forest.

Morphological feature M. moribidii Idris, Hutchings & Arshad, 2014 M. kertehensis sp. nov.
(Idris et al. 2014oks present in the paratype of M. moribidii AM W.38690.Additionally, M. kertehensis sp.nov.has a black dot at the base of dorsal cirri in median and posterior chaetigers, possibly a reservoir of blood to irrigate the branchiae, which is absent in M. moribidii.It is worth mentioning that comparisons between the two species were based only on morphological features as there is no sequence data published for M. moribidii.Furthermore, each species lives in a different habitat.Marphysa kertehensis sp.nov.wasfound in the driftwood within the mangrove area dominated by Exoecaria agallocha, meanwhile M. moribidii inhabits mangrove forest with Rhizophora spp., Avicennia alba and Sonneratia caseolaris(Idris et al. 2014).

Table 6 .
Morphological features comparison between Marphysa Group B (Sanguinea) described in this study and species occurring within Malaysian water bodies (South China Sea).The features for new species are based on the holotype, with variation in parentheses for paratypes.Abbreviations: MF: maxillary formula, roman numerals refer to number of maxilla; PR-I: first peristomial ring; PR-II: second peristomial ring; p/a: present/absent; NIA: no information available.The major differences between the species are marked with asterisk (*).