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Research Article
Unravelling the convoluted nomenclature of Marphysa simplex (Annelida, Eunicidae) with the proposal of a new name and the re-description of species
expand article infoIsabel Cristina Molina-Acevedo§, Izwandy Idris
‡ Universiti Malaysia Terengganu, Kuala Nerus, Malaysia
§ El Colegio de la Frontera Sur, Chetumal, Mexico
Open Access

Abstract

Marphysa simplex is a name that three species bear within the same genus, but each has a different authority and morphological characteristics. This homonymy condition leads to taxonomic confusion and the finite designation of name-bearing is imperative. The current study focuses on two species identified as M. simplex Crossland, 1903 and M. simplex Treadwell, 1922 and a third one, recently considered a secondary homonymy, M. simplex (Langerhans, 1884), is also assessed. The available type specimens were examined and re-described in detail using updated characters and the original descriptions. Marphysa simplex (Langerhans, 1884) is herein judged as an indeterminable species. Marphysa simplex Crossland, 1903 is confirmed as a junior synonym of M. teretiuscula (Schmarda, 1861a) because the differences are minimal. Moreover, M. teretiuscula has characteristics similar to Group B2 (Sanguinea-group; only compound spinigers), instead of the Teretiuscula-group (compound spinigers in the anterior region, subacicular limbate in all chaetigers). On the other hand, M. simplex Treadwell, 1922 is a junior primary homonym of Crossland’s species replaced by M. fijiensis nom. nov. with the chaetal arrangement similar to Group A (limbate chaetae only). In conclusion, the name M. simplex is now unacceptable. The hypothesis on species group only with limbate chaetae and the redescription on M. teretiuscula is also given.

Key Words

Homonymy, limbate chaetae, morphological review, synonymy, type material

Introduction

Within the long story of Marphysa de Quatrefages, 1865, the name M. simplex has been referred to in several homonymy cases since three species worldwide bear this name: Marphysa simplex Crossland, 1903, M. simplex Treadwell, 1922 and M. simplex (Langerhans, 1884). Simultaneously, the names M. simplex Crossland, 1903 and Treadwell 1922 have been used as synonymies of two other Marphysa species (Glasby and Hutchings 2010). In this study, we provide an analysis of these taxonomic issues.

The name M. simplex was firstly used by Crossland (1903) for two specimens from Zanzibar (Tanzania). Although Crossland proposed a new name, he also stated that his specimens resemble M. teretiuscula (Schmarda, 1861a) from Sri Lanka because both species are present in the Indian Ocean. Nonetheless, he could not make an accurate comparison because Schmarda’s description was short and poorly illustrated (Crossland 1903; Glasby and Hutchings 2010).

About two decades later, Treadwell (1922) described a new species, M. simplex, based on one specimen found together with M. macintoshi Crossland, 1903 in Suva Harbour, Fiji. Even though Treadwell knew about Crossland’s contributions, it is uncertain why he used an already established name for his new species.

Later, a third species with the same name appeared as a secondary homonym (ICZN 1999, Art. 57.3). Langerhans (1884) described Amphiro simplex, based on a single specimen from Madeira (Portugal). Amphiro Kinberg, 1865 was considered a junior synonym of Marphysa by Hartman (1949); therefore, the species described in that genus became part of Marphysa, including Langerhans’ species.

The three species named M. simplex differ in morphology and can be classified into three of the informal groups proposed by Fauchald (1970). Crossland’s specimens belong to Marphysa B2 group (with compound spinigers only), Treadwell’s specimens belong to A group (without compound chaetae) and Langerhans’s species to group C (with compound falcigers only).

Currently, the species M. simplex (Langerhans) is considered indeterminable by Molina-Acevedo and Idris (accepted, but not yet published) since the type material is lost and the original description lacks enough diagnostic characters for comparison, even if new topotypes are found. The other two species of M. simplex were accepted as synonyms of different Marphysa species. Glasby and Hutchings (2010), who commented about these homonymies, considered M. simplex Crossland a junior synonym of M. teretiuscula following Crosland’s comments regarding the similarity and also because the body shape and the length of the peristomial appendages were consistent between both species. Likewise, Glasby and Hutchings (2010) synonymised M. simplex Treadwell with M. mossambica (Peters, 1854) because the only differences between both species were size-related variations.

In the present study, we confirm the synonymy of M. simplex Crossland and M. teretiuscula after a detailed evaluation of the type material. However, we propose the re-establishment of M. simplex Treadwell, as it is distinguished morphologically from M. mossambica. Since M. simplex Treadwell is a primary homonym of Crossland’s species (ICZN 1999, Art. 53.3) and therefore no longer valid, we hereby replace Treadwell’s name by erecting Marphysa fijiensis nom. nov. (ICZN 1999, Art. 60.3). Likewise, we provide re-descriptions of M. teretiuscula and M. fijiensis nom. nov., based on the type materials, some observations regarding group A (Fauchald 1970) and a group of Marphysa species with compound spinigers and subacicular limbate chaetae (Glasby and Hutchings 2010). Comparative Tables with species similar to M. fijiensis nom. nov. and M. teretiuscula are included.

Material and methods

The materials reviewed in this study were deposited in the following institutions: American Museum of Natural History, New York, USA (AMNH), Australian Museum (AM), The Natural History Museum, London (BNHM), Natural History Museum, Vienna, Austria (NHMW), National Museum of Natural History, Smithsonian Institution, Washington D.C., USA (USNM) and Museum of Natural History, Berlin, Germany (ZMB).

The re-descriptions of species were illustrated with digital photographs. A series of photos were stacked using HeliconFocus 6 (Method A) software to improve the depth of field and the final images were edited and assembled into plates using Adobe Photoshop 2020. The re-descriptions include: prostomium, body, branchiae, maxillary apparatus, parapodia, compound chaetae and simple chaetae. The terminology to describe the overall morphology of characters followed those recently provided by Molina-Acevedo and Carrera-Parra (2015, 2017), Zanol et al. (2016) and Molina-Acevedo (2018). Paired and unpaired maxillae were indicated as ‘M’ followed by a Roman number (e.g. MI, MII). The maxillary apparatus and the pectinate chaetae were described according to Molina-Acevedo and Carrera-Parra (2015, 2017) and Zanol et al. (2016), respectively. In addition, the definition of long and short branchial filaments, proposed by Molina-Acevedo and Idris (2020), is followed. Three or five parapodia per species were dissected to compare the different shapes of the parapodial cirri, lobes and chaetae throughout the body.

Some specimens studied were posteriorly incomplete; hence, morphological measurements for the length up to chaetiger 10 (L10) and width at chaetiger 10 (W10), excluding parapodia, were used as a size estimate of an individual worm. Additionally, the total length (TL) and the total number of chaetigers (TChae), the chaetiger number and side (R for right, L for left) from which branchiae and subacicular hooks emerged, were also recorded. Furthermore, for specimens from M. teretiuscula, linear regression analyses were included to evaluate the relationships between L10, W10 and several morphological features, including the starting of branchiae and subacicular chaetae and the last chaetiger with developed postchaetal lobe. The degree of predictability of variation (coefficient of determination) in the features according to the sizes is given as R2 (e.g. R2 = 0.7, p = 0.05, n = 8).

Results

Systematic

Order Eunicida Dales, 1962

Family Eunicidae Berthold, 1827

Genus Marphysa de Quatrefages, 1865

Marphysa fijiensis nom. nov.

Figures 1, 2, 3, 4, Table 1

Marphysa simplex Treadwell, 1922: 151–152, pl. 5, figs 8–12, text-figs 39 (non Crossland, 1903); –Hartman 1956: 254, 262, 268, 286.

Material examined

Holotype. Fiji · Suva Harbour; Apr–Jun, 1920; AMNH 1920–1530.

Comparative material examined

Eunice mossambica Peters, 1854

Mozambique · one specimen and vial with six parapodia; lectotype ZMB 4005 · 3 adult specimens, same data as for the lectotype; paralectotypes ZMB 47 · one specimen; same data as for the lectotype; ZMB F2046 · seven adult specimens; same data as for the lectotype; ZMB 4005.

Marphysa moribidii Idris, Hutchings & Arshad, 2014

Malaysia · two adult specimens; Pantai Kelanang, Morib, Selangor; 2°45'39.85"N, 101°26'08"E; in mangrove vegetation; 19 Jul 2011; I. Idris leg.; paratype AM W.38690.

Nauphanta novaehollandiae Kinberg, 1865

Australia · one specimen divided into four vials, one of them with maxillary apparatus; Sydney Port Jackson; 33°54'S, 151°11'E; Eugenie Epx. 1851–53; holotype SMNH-type-432.

Etymology

The new name denotes the geographic region where the specimen was collected.

Description

Holotype complete (Fig. 1A–F), ventrally dissected (Fig. 1C), with 198 chaetigers, L10 = 8.2 mm, W10 = 2.5 mm, TL = 93 mm. Anterior region with dorsum convex, flat ventre, body depressed from chaetiger 6 (Fig. 1D), widest at chaetiger 17, tapering after chaetiger 41.

Figure 1. 

Marphysa fijiensis nom. nov., holotype (AMNH 1920–1530). A, B. Anterior end, dorsal view; C. Anterior end, ventral view; D. Anterior end, lateral view; E. Median region, lateral and ventral views; F. Pygidium, lateral view. Scale bars: 0.35 mm (A); 2 mm (B–D); 0.5 mm (E, F).

Prostomium bilobed, 1.3 mm long, 1.6 mm wide; lobes frontally rounded; median sulcus shallow and deep ventrally (Fig. 1A, B). Prostomial appendages in semicircle, median antenna isolated by a gap. Palps reaching second peristomial ring; lateral antennae reaching first chaetiger; median antenna reaching second chaetiger. Palpophores and ceratophores ring-shaped, short, slender; palpostyles and ceratostyles tapering, thick. Eyes absent.

Peristomium (1.7 mm long, 2.3 mm wide) larger than prostomium, first ring twice as long as second ring, separation between rings distinct on all sides (Fig. 1A–C). Ventral lip dissected, with several shallow wrinkles (Fig. 1C).

Maxillary apparatus lost, according to Treadwell with MF = 1+1, 5+5–6, 9+0 2+8, 1+1.

Branchiae pectinate with up to five long filaments, from chaetigers 22 to 184L–195R (Figs 1E, 2D, E). Six first branchiae with one filament; reaching maximum five filaments in chaetigers 79L–178L; last 12 branchiae with one filament (Fig. 3A). Branchial filaments longer than dorsal cirri, except in first six and last 10 branchiae.

Figure 2. 

Marphysa fijiensis nom. nov., holotype (AMNH 1920–1530). A. Chaetiger 3; B. Chaetiger 8; C. Chaetiger 14; D. Chaetiger 123; E. Chaetiger 188. Marphysa mossambica (Peters, 1854), lectotype (ZMB 4005a). F. Chaetiger 3; G. Chaetiger 8; H. Chaetiger 15; I. Chaetiger 293; J. Chaetiger 398. All chaetigers in anterior view. The colours in drawings indicate the prechaetal (light brown), chaetal (light yellow) and postchaetal (light green) lobes. Scale bars: 0.1 mm (A–E); 0.2 mm (F–J).

Figure 3. 

Distribution of branchial filaments throughout the body. A. Holotype of Marphysa fijiensis nom. nov. (AMNH 1920–1530) with L10: 8.2 mm, TL: 93 mm and 198 chaetigers; B. Paralectotype of Marphysa mossambica (Peters, 1854) (ZMB 47) with L10: 10.3 mm, TL: 290 mm and 429 chaetigers.

First two parapodia smaller; best developed in chaetigers 4–21, following parapodia gradually decreasing in size. Dorsal cirri conical in all chaetigers; longer than ventral cirri in anterior and posterior chaetigers, of similar size in median chaetigers; best developed in chaetigers 3–30, gradually decreasing posteriorly (Fig. 2A–E). Prechaetal lobes short, as transverse folds in first three chaetigers, following lobes with upper edge longer than lower; transverse folds in most posterior chaetigers (Fig. 2A–E). Chaetal lobes rounded in most chaetigers, shorter than postchaetal lobe, with aciculae emerging dorsal to mid-line; from chaetiger 33, longer than other lobes, aciculae emerging in mid-line (Fig. 2A–E). Postchaetal lobes slightly developed in first 55 chaetigers; ovoid in first two chaetigers, rounded in the following ones, progressively smaller from chaetiger 14; from chaetiger 56 inconspicuous (Fig. 2A–E). Ventral cirri digitiform in first 13 chaetigers; in chaetigers 14 to 126 with rounded, poorly developed swollen base and digitiform tip; conical from chaetiger 127, gradually decreasing in size posteriorly (Fig. 2A–E).

Aciculae blunt, basally reddish and translucent distally; colourless in posterior chaetigers (Fig. 2A–E). First two chaetigers with two aciculae; in chaetigers 3–10 with three or four aciculae; in chaetigers 11–24 with four aciculae; in chaetigers 25–43 with three aciculae; in chaetigers 44–85 with two aciculae; from 86 with only one acicula. In median-posterior region, aciculae twice as wide as subacicular hook (Fig. 4F, G).

Figure 4. 

Marphysa fijiensis nom. nov., holotype (AMNH 1920–1530). A. Limbate chaetae, chaetiger 8; B. Limbate chaetae, chaetiger 188; C. Thick isodont narrow, with short and slender teeth, chaetiger 3; D. Thick isodont wide with short and slender teeth, chaetiger 152; E. Thick isodont wide with short and slender teeth, chaetiger 188; F. Unidentate subacicular hook, chaetiger 123; Bidentate subacicular hook, chaetiger 152. Arrows in F: upper one indicates the acicula; lower one indicates the hood of the subacicular hook. Scale bars: 40 μm (A, B, F, G); 12.5 μm (C–E).

Limbate chaetae in supra- and subacicular positions. Limbate supracicular chaetae reduced in number around chaetiger 16, chaetae of two lengths in same chaetiger, with longer blades in dorsal position and with short blades in ventral position. Limbate subacicular of two lengths, with short blades in dorsal position and with longer blades in ventral position (Fig. 4A, B). Two types of pectinate chaetae; in all chaetigers, 2–3 thick isodont narrow chaetae, with up to 16–18 teeth short and slender teeth (Fig. 4C); in median-posterior chaetigers, 4–5 thick isodont wide chaetae, with up to 38–42 teeth short and slender teeth (Fig. 4D, E); anodont pectinate chaetae not observed. Compound chaetae absent. Subacicular hooks starting from chaetigers 38R–39L, one per chaetiger, with discontinuous distribution, in last 25 chaetigers, the hooks are absent; unidentate in median region with one hood (possibly with second hood broken) (Fig. 4F); bidentate in median-posterior region, translucent, with blunt teeth, distal tooth directed upwards, proximal tooth larger, directed laterally (Fig. 4G).

Pygidium with two pairs of anal cirri broken (Fig. 1F).

Distribution

Known only from the type locality.

Habitat

Uncertain. Possibly coral reefs or mudflats (Treadwell 1922).

Remarks

The first comment on the synonymy of Marphysa fijiensis nom. nov. (as M. simplex Treadwell, 1922) and M. mossambica was made by Hartman (1956). Subsequently, Glasby and Hutchings (2010) supported this idea, stating that the morphology described by Treadwell was very similar to the smaller-sized specimens of M. mossambica. However, after a detailed morphological comparison of both species’ type material, we found marked differences. Marphysa fijiensis nom. nov. lacks eyes, whereas they are present in M. mossambica. Additionally, M. fijiensis nom. nov. (L10: 8.2 mm) has a maximum number of five branchial filaments in the median region (Fig. 3), whereas M. mossambica (L10:8.5–11.5 mm), has a maximum number of eight branchial filaments in the mid-posterior region (Fig. 3). In M. fijiensis nom. nov., the chaetal lobe is rounded in the anterior region and the postchaetal lobe is oval in the first three chaetigers. In contrast, in M. mossambica, the chaetal lobe is rectangular in the anterior region and the postchaetal lobe is digitiform in the first three chaetigers. Likewise, M. fijiensis nom. nov. has the subacicular hook present from chaetiger 25, contrasting to chaetigers 35–65 in M. mossambica.

Marphysa fijiensis nom. nov. resembles M. moribidii Idris, Hutchings & Arshad, 2014 and M. novaehollandiae (Kinberg, 1865) in lacking compound chaetae. However, M. fijiensis nom. nov. lacks the peduncle in prostomial appendages, with swollen base in ventral cirri starting from chaetiger 14 and the acicula is twice as wide as the subacicular hook in the median-posterior region. In contrast, M. moribidii (L10: 12.2–20 mm) has a peduncle at the base of the palpo- and ceratostyles, bears ventral cirri with a swollen base starting from chaetiger 6 and has a subacicular hook similar in width to the acicula throughout the body. Furthermore, M. fijiensis nom. nov. has the prechaetal lobe as a transverse fold throughout the body, the chaetal lobe rounded throughout the body, the ventral cirri with a swollen base starting from chaetiger 14 and the subacicular hook starting from chaetiger 25; while M. novaehollandiae (L10: 6.6–9.6 mm) has the prechaetal lobe with dorsal edge longer than the ventral side in the first chaetigers, the chaetal lobe rectangular in the anterior region, the ventral cirri with a swollen base starting from chaetiger 8 and the subacicular hook starting from chaetigers 39–42. The comparison of M. fijiensis nom. nov. with related species is provided in Table 1.

Table 1.

Morphological features of Marphysa group A sensu Fauchald (1970). Abbreviations: MF: Maxillary formula, roman numerals refer to number of maxilla; MxC: maxillary carriers; CIS: closing system; COp: cavity opening; PR-I: first peristomial ring; PR-II: second peristomial ring; Chaet: chaetiger; p/a: present/absent; AR: anterior region; MR: median region; PR: posterior region; SH: subacicular hook. INSS: Isodont narrow with short and slender teeth; INLS: Isodont narrow with long and slender teeth; IWSS: Isodont wide with short and slender teeth; IWLS: Isodont wide with long and slender teeth; AWLT: Anodont wide with long and thick teeth.

Morphological feature M. moribidii Idris et al., 2014 M. mossambica (Peters, 1854) M. novaehollandiae (Kinberg, 1865) M. fijiensis nom. nov.
Source of information paratypes AM W. 38690; additional material lectotype ZMB 4005a; paralectotypes ZMB 47; ZMB F2046, ZMB 4005 holotype SMNH-type-432; AM W.33021 holotype AMNH 1920–1530
Size (mm): L10, W10 12.2–20, 6.3–8.2 8–11.5, 3.6–8.1 6.6–9.6, 4–4.2 8.2, 2.5
Prostomium: shape bilobed bilobed bilobed bilobed
Palps: reaching PR–II PR–II or Chaet 1 PR–II PR–II
Lateral antennae: reaching PR–II or Chaet 1 middle Chaet 1 or 2 middle Chaet 1 Chaet 1
Median antennae: reaching Chaet 1 or 2 Chaet 2 or 3 middle Chaet 2 Chaet 2
Peduncle in prostomial appendages present absent absent absent
Eyes absent present present absent
MF: MII, MIII, MIV 5–6+4–6, 7–8, 6+8–10 5+5–6, 6–7, 3–4+8–9 4–5+6, 7, 5+8–9 5+5–6, 9, 2+8
MI vs. MxC: proportion 2.4–2.8× longer than MxC 2–3× longer than MxC 2.4–3.2× longer than MxC ?
MI vs. CIS: proportion 4.3–5.7× longer than CIS 5–7× longer than CIS 4.4–8× longer than CIS ?
MII vs. COp: proportion 4.3–4.7× longer than COp 3.2–4× longer than COp 4.5–5.3× longer than COp ?
Branchiae: shaped pectinate pectinate pectinate pectinate
Branchiae: start chaetiger; last chaetiger before pygidium 27–39; 15–37 23–48; 29–126 21–25; 15 22; 3
Branchial filaments: numbers; length of the filaments 7–10; long 7–8; long 6–7; long 5; long
Dorsal cirri: shaped conical conical with wide base conical conical
Prechaetal lobe: shaped transverse fold AR: upper edge longer than lower, MR, PR: transverse fold AR, MR: upper edge longer than lower, PR: transverse fold AR, MR: upper edge longer than lower, PR: transverse fold
Chaetal lobe: shaped rounded AR: rectangular MR, PR: rounded AR, MR: rectangular, PR: rounded rounded
Developed postchaetal lobe: end chaetiger 50–96 27–70 32–38 55
Postchaetal lobe: shape in body regions Chaet 4: digitiform short, Chaet 4–10, 10: rounded Chaet 4: digitiform short, Chaet 4–10, 10: rounded Chaet 4: ovoid, Chaet 4–10, 10: rounded Chaet 4: ovoid, Chaet 4–10, 10: rounded
Ventral cirri in first chaetigers: shape digitiform digitiform digitiform digitiform
Ventral cirri with swollen base: start chaetiger; last chaetiger before pygidium 6; 62–96 7–9; 96–208 8; 41 14; 72
Ventral cirri in most posterior chaetigers: shape conical conical conical conical
Aciculae: shape; colour blunt, dark blunt, dark blunt, dark blunt, dark
Subacicular limbate chaetae: (p/a); distribution present; all chaet present; all chaet present; all chaet present; all chaet
Pectinate chaetae: type in AR; MR, PR INLS; IWSS, IWLS, AWLT INLS; IWSS, IWLS, AWLT INLS; IWSS, IWLS, ? INSS; IWSS
Pectinate chaetae: number per type 1–2; 3–4, 1–2, 1–2 1–2; 2–3, 2–3, 1–2 1–2; 1–2, 3–4; ? 2–3; 4–5
Pectinate chaetae teeth: number per type 18; 52, 26, 7 18–19; 56, 27, 9–10 25; 50–51, 35; ? 16–18; 38–42
Subacicular hook: start chaetiger 56–65 35–65 39–42 38
Subacicular hook: shape; colour bidentate, translucent bidentate, translucent bidentate, translucent MR: unidentate, PR: bidentate, translucent
Width acicula vs. SH in MR-PR: proportion similar width Acicula 2× wider than SH Acicula 2× wider than SH Acicula 2× wider than SH
Subacicular hook: distribution discontinuous discontinuous discontinuous discontinuous

Marphysa teretiuscula (Schmarda, 1861a)

Figures 5, 6, 7, 8, 9, Table 2

Eunice teretiuscula Schmarda, 1861a: 129, pl. 32, fig. 59, text-figs a–d, f, OK, UK; Grube 1878: 59.

Marphysa teretiusculade Quatrefages 1866: 337; Ehlers 1868: 359; Crossland 1903: 136; – Hartman 1959: 332; – Glasby and Hutchings 2010: 32, 40–41, table 2; Liu et al. 2017: 244–247, table 3; – Liu et al. 2018: 210–211, table 1.

Marphysa simplex Crossland, 1903: 140–141, pl. 15, figs. 11–12, text-fig. 13.

Material examined

Eunice teretiuscula Schmarda, 1861a

Sri Lanka · two specimens, one of them missing anterior end; Trincomalee, east of Sri Lanka; May 1853 to Jan 1854; L.K. Schmarda leg.; syntypes NHMW type 1092.

Marphysa simplex Crossland, 1903

Zanzibar · two adult specimens; 11 Jan 1934; Murray Exped. St. 104, Petersen Grab, V.310, 207 m; syntypes BNHM type 1937.9.2.325.

Other material

Marphysa teretiuscula (Schmarda, 1861a)

Mozambique · two specimens; Morrumbene Estuary; 16 Jan 1954; BNHM 1955.4.1.21-25.

India · one specimen; Ratnagiri Creek, Shirgaon, Maharashtra; 17°17'13.78"N, 73°17'13.87"E; 18 Apr 1994; USNM 1128572 · one specimen; same data as for preceding; USNM 1128570.

Comparative material examined

Marphysa furcellata Crossland, 1903

Zanzibar · two specimens; 1901; between tidemarks, 27.4 m; C. Crossland leg.; syntypes BNHM 1924.3.1.139.

Marphysa macintoshi Crossland, 1903

Zanzibar · three specimens; 1901–1902; collected by digging in sand between tidemarks on both east and west coast of Zanzibar; syntypes BNHM 1924.3.1.22-3, slide BNHM.1924.3.1.22A.

Description

Syntype NHM type 1092 incomplete, gravid female, with 210 chaetigers, L10 = 9.3 mm, W10 = 5 mm TL = 860 mm (Fig. 5A–C). Anterior region with dorsum convex, flat ventre (Fig. 5C, E); body depressed from chaetiger 13 (Fig. 5C, E), widest at chaetiger 51, tapering after chaetiger 173.

Figure 5. 

Marphysa teretiuscula (Schmarda, 1861a). A. Anterior end, dorsal view; B. Anterior end, ventral view; C. Anterior end, lateral view; D. Anterior end, dorsal view; E. Anterior end, lateral view; F. Median region, ventral view; G. Pygidium, dorsal view; H. Maxillary apparatus, dorsal view; I. Left MI-II-III-IV-V, lateral view; J. Attachment lamella in left side, dorsal view; K. Attachment lamella in right side, lateral view; L. Mandible, ventral view. A–C, H–L. from M. teretiuscula (Schmarda, 1861) syntype 1 (NHMW type 1092); D–G. from Marphysa simplex Crossland, 1903 syntype 1 (BNHM 1955.4.1.21-25). al-MIII: attachment lamella MIII; al-MIV: attachment lamella MIV; al-MIV-L: attachment lamella MIV on left side; al-MIV-R: attachment lamella MIV on right side; MI-R: Maxilla I on right side; MII-R: Maxilla II on right side. Scale bars: 2.3 mm (A–C); 3.1 mm (D–F); 1.16 mm (G); 3.0 mm (H, I, L); 1.13 mm (J); 0.9 mm (K).

Prostomium bilobed, 4 mm long, 2.5 mm wide; lobes frontally rounded; median sulcus (Fig. 5A, B, D) shallow and deep ventrally. Prostomial appendages in semicircle, median antenna isolated by a gap. Palps reaching second chaetiger; lateral antennae reaching middle of third chaetiger; median antennae reaching fourth chaetiger. Palpophores and ceratophores ring-shaped, short, thick; palpostyles and ceratostyles tapering, slender. On right side with two palpostyle in the same palpophore (Fig. 5C). Eyes oval, brown, between palps and lateral antennae.

Peristomium (2 mm long, 5.2 mm wide) wider than prostomium, first ring twice as long as second ring, separation between rings distinct on all sides (Fig. 5A–E). Ventral lip with slight central depression, with several shallow wrinkles (Fig. 5B).

Maxillary apparatus with MF = 1+1, 4+4, 5+0, 5+7, 1+1 (Fig. 5H). MI three times longer than length of maxillary carriers. MI forceps-like, MI four times longer than closing system (Fig. 5H, I); sclerotised ligament between MI and MII. MII wider than rest of maxillae, with triangular teeth; MII 3.2 times longer than cavity opening (Fig. 5H); ligament between left MII–MIII and right MII–MIV, slightly sclerotised. MIII with triangular teeth; with irregular attachment lamella, situated in centre of ventral edge of maxilla, slightly sclerotised (Fig. 5I). Left MIV with two teeth larger than rest of teeth; attachment lamella semicircle, wide, better developed in right portion, situated 2/3 along anterior edge of maxilla (Fig. 5J). Right MIV with four teeth larger than rest of teeth; attachment lamella semicircle, wide, better developed in central portion, situated 2/3 along anterior edge of maxilla (Fig. 5K). MV square, with a short triangular tooth. Mandibles dark; with calcareous cutting plates; sclerotised cutting plates brown, with nine growth rings (Fig. 5L).

Branchiae from chaetiger 32, with up to five long filaments; with two forms: palmate with short button-shaped branchial stem in anterior chaetigers (Fig. 6F, H), pectinate in median chaetigers (Fig. 6G). In second syntype, branchiae ending 25 chaetigers before pygidium. One filament in chaetigers 32L–34L; 2 in chaetigers 35L–39L; 3 in chaetigers 40L–48L; 3, 4 or 5 from chaetiger 49L to last chaetiger of the fragment. In second syntype, last 18 branchiae with one filament. Branchial filaments longer than dorsal cirri.

Figure 6. 

Marphysa teretiuscula (Schmarda, 1861a). A, B. Chaetiger 3; C. Chaetiger 7; D. Chaetiger 12; E. Chaetiger 14; F. Chaetiger 47; G. Chaetiger 97; H. Chaetiger 143; I. Chaetiger 162; J. Chaetiger 44 before pygidium; K. Chaetiger 256. All chaetigers in anterior view. A, D, F, H. from M. teretiuscula (Schmarda, 1861a) syntype 1 (NHMW type 1092); J. from M. teretiuscula (Schmarda, 1861a) syntype 2 (NHMW type 1092); B, C, E, G, I, K. from Marphysa simplex Crossland, 1903 syntype 1 (BNHM 1955.4.1.21-25). Arrows in F, H. indicate the button-shaped branchial stem. Scale bars: 0.2 mm (A, D, F, H, J); 0.1 mm (B, C, E, G, I, K).

First pair of parapodia small; best developed in chaetigers 11–56, following parapodia gradually decreasing in size. Dorsal cirri conical in all chaetigers; longer than ventral cirri in anterior and posterior chaetigers, shorter in median chaetigers; best developed in chaetigers 3–37, following gradually decreasing in size (Fig. 6A–K). Prechaetal lobes short, in anterior chaetigers dorsal edge longer than ventral, in median-posterior chaetigers, as transverse fold (Fig. 6A–K). Chaetal lobes rounded in first 35 chaetigers, shorter than other lobes, with aciculae emerging dorsal to mid-line; triangular from chaetiger 36, longer than other lobes, with aciculae emerging in mid-line (Fig. 6A–K). Postchaetal lobes well developed in first 56 chaetigers; ovoid with dorsal edge longer than ventral edge in following chaetigers; progressively smaller from chaetiger 19; from chaetiger 57, inconspicuous (Fig. 6A–K). Ventral cirri conical in first five chaetigers; from chaetiger 6 to last chaetiger of fragment with short oval swollen base and digitiform tip (Fig. 6A–K). Second syntype with ventral cirri with short oval swollen base and digitiform tip up to 27 chaetigers before pygidium; digitiform in following ones, gradually decreasing in size posteriorly.

Aciculae blunt, basally reddish and translucent distally (Fig. 6A–K). First two chaetigers with two aciculae; in chaetigers 3–5 with three or four; in chaetigers 6–47 with four or five; in chaetigers 48–139 with three; from chaetiger 140, with two. In second syntype, last 20 chaetigers with one acicula.

Limbate chaetae of two lengths in same chaetiger, dorsalmost chaetae longer; reduced in number around chaetiger 13. Three types of pectinate chaetae; from chaetiger 11 thin, isodont narrow chaetae, with short and slender teeth; in anterior chaetigers with 1–2 pectinate and with up to 21–22 teeth; in median-posterior chaetigers, with 20–25 pectinate and 30–32 teeth (Fig. 7A, B). In median-posterior chaetigers, 3–4 thick, isodont wide chaetae, with up to 16–18 long and wide teeth (Fig. 7C). In posterior chaetigers, 2–3 thick, anodont wide chaetae, with up to 6–7 long and thick teeth (Fig. 7D). Compound spinigers present in all chaetigers, with blades of two lengths in the same chaetiger, shorter ones more abundant (Fig. 7E, F, G). Subacicular hooks present from chaetiger 33 to 140, with continuous distribution, one or two per chaetiger (second one replacement); unidentate in anterior chaetigers (Fig. 7H), bidentate in median chaetigers, basally reddish translucent distally; with blunt teeth, distal and proximal teeth of similar sizes, booth teeth directed upwards (Fig. 7I).

Figure 7. 

Marphysa teretiuscula (Schmarda, 1861a). A. Thin, isodont narrow pectinate, with short and slender teeth, chaetiger 47; B. Thin, isodont narrow pectinate, with short and slender teeth, chaetiger 189; C. Thick, isodont wide, with long and wide teeth, chaetiger 44 before pygidium; D. Thick, anodont wide, with long and wide teeth, chaetiger 256; E. Compound spinigers, chaetiger 44 before pygidium; F. Compound spiniger, chaetiger 211; G. Compound spinigers, chaetiger 47; H. Unidentate subacicular hook, chaetiger 47; I. Bidentate subacicular hook, chaetiger 73 before pygidium. A, B. from M. teretiuscula (Schmarda, 1861a) syntype 1 (NHMW type 1092); C, E, I. from M. teretiuscula (Schmarda, 1861a) syntype 2 (NHMW type 1092); D, F. from Marphysa simplex Crossland, 1903 syntype 1 (BNHM 1955.4.1.21-25); G, H. from M. simplex Crossland, 1903 syntype 2 (BNHM 1955.4.1.21-25). Scale bars: 20 μm (A–D, G); 60 μm (E); 50 μm (F, H, I).

In second syntype, pygidium with dorsal pairs of anal cirri, as long as last 12 chaetigers; ventral pair of anal cirri short, as long as last three chaetigers (Fig. 5G).

Variation

Material examined varied in the following features: L10 = 3.1–12.4 mm, W10 = 0.8–5 mm, TChae = 88–265. Palps reaching middle of first peristomial ring or first chaetiger; lateral antennae reaching first or middle of first chaetiger; median antenna reaching middle of first or second chaetiger. Maxillary formula: MII 4–6+4–7, MIII 5–8, MIV 4–5+7–9. MI is 3–3.1× longer than maxillary carriers; MI is 4.4–5.5× longer than closing system; MII is 2.7–3.4× longer than cavity opening. Branchiae starting from chaetigers 15–32 and disappearing 7–12 chaetigers before pygidium. The maximum number of branchial filaments varies from two to six. Postchaetal lobes well developed in first 20–56 chaetigers. Ventral cirri with swollen base starting from chaetigers 4–8 and disappearing 34–68 chaetigers before pygidium. Start of subacicular hooks from chaetigers 23–38.

Regression analyses showed a correlation between L10/W10 and the first branchiate chaetiger (R² = 0.7328, p = 1.65708E-05, n = 7, Fig. 8A), the last chaetiger with developed postchaetal lobe (R² = 0.7976, p = 0.00028646, n = 7, Fig. 8B) and the first chaetiger with subacicular hook (R² = 0.6291, p = 2.02774E-07, n = 7, Fig. 8C). Most of the specimens were incomplete and regression analysis regarding the maximum number of branchial filaments in the body could not be performed.

Figure 8. 

Large chaetiger 10 (L10)/Wide chaetiger 10 (W10)-dependent variation of some morphological features in Marphysa teretiuscula (Schmarda, 1861a). A. First chaetiger where the branchiae start (R² = 0.7328, p = 1.65708E-05, n = 7); B. Last chaetiger where the postchaetal lobe is developed (R² = 0.7976, p = 0.00028646, n = 7); C. Chaetiger where the subacicular hook starts (R² = 0.6291, p = 2.02774E-07, n = 7).

Distribution

Sri Lanka, Maharashtra (India), Zanzibar.

Habitat

Unknown. Schmarda (1861a) did not indicate the habitat of the species.

Remarks

Schmarda (1861a) collected M. teretiuscula (firstly in the genus Eunice) in the east of Ceylon (now Sri Lanka) during a series of expeditions around the world to collect fauna and flora (Schmarda 1859; Villalobos-Guerrero 2019). The syntypes label only states ‘Trincomalie’ (Trincomalee) as the collecting site, but no collecting date is given. However, the expedition notes (Schmarda 1861b) state that he visited Ceylon from May 1853 to January 1854, whereby, based on this information, the syntypes of M. teretiuscula were most likely collected during this time.

Crossland (1903) described M. macintoshi, M. simplex and M. furcellata from Zanzibar. These species were differentiated, based on the shape of the prostomium and the pectinate chaetae. However, some authors considered these features irrelevant over time and proposed several synonyms between them or other species from distant regions. For instance, Fauvel (1919) considered M. furcellata to be a junior synonym of M. sanguinea Montagu, 1813. On the contrary, Day (1957) indicated that M. sanguinea differed from M. furcellata by having bidentate subacicular hooks, whereas, in the latter species, they are unidentate. However, Day regarded M. furcellata as a junior synonym of M. simplex (Crossland). Later, Day (1962) pointed out that M. furcellata and M. simplex (Crossland) were synonyms of M. macintoshi, considering that the prostomium’s shape was insufficient to differentiate them. More recently, Glasby and Hutchings (2010) recognised that an entire prostomium is useful to distinguish M. macintoshi from M. furcellata and M. simplex (Crossland). Simultaneously, Glasby and Hutchings (2010) compared M. simplex (Crossland) and M. teretiuscula, but they also did not detect morphological differences between them. After examining the type materials, we confirm the validity of Crossland’s species M. macintoshi and M. furcellata and the synonymy of M. simplex (Crossland) with M. teretiuscula (see Figs 57).

Marphysa teretiuscula resembles M. borradailei Pillai, 1958 from Sri Lanka and the Indian Ocean, M. furcellata from Zanzibar, M. gravelyi Southern, 1921 from Chilka Lake, India, M. macintoshi from Zanzibar and M. madrasi Hutchings, Lavesque, Priscilla, Daffe, Malathi & Glasby, 2020 from Ennore Creek, India by having compound spinigers and inhabiting the same geographical area. However, M. teretiuscula bears only subacicular chaetae compound spinigers, while M. borradailei, M. gravelyi and M. madrasi have both subacicular spinigers and limbate chaetae. Furthermore, M. teretiuscula has distinct bilobed prostomium, in contrast to an entire prostomium in M. macintoshi. Moreover, M. teretiuscula has palmate branchiae with a short button-shaped branchial stem in the anterior region, the postchaetal lobe is rounded in the first three chaetigers and the subacicular hooks are reddish basally and translucent distally. In contrast, M. furcellata has pectinate branchiae in the anterior region, digitiform postchaetal lobes in the first chaetigers and translucent subacicular hooks. In addition, M. teretiuscula, M. furcellata and M. macintoshi differ by distributing the branchial filaments throughout the body. In M. teretiuscula, the maximum number of five branchial filaments is present only in a small/low number of chaetigers (between chaetiger 86 and 106), while in M. furcellata and M. macintoshi, the maximum number of five branchial filaments (in each species) is found in a larger number of chaetigers (in M. furcellata from chaetiger 80 to 120+ and in M. macintoshi from chaetiger 105 to 236; Fig. 9).

Figure 9. 

Distribution of branchial filaments throughout the body. A. Syntype 1 of Marphysa simplex Crossland, 1903 (BNHM 1924.3.1.1-2) with L10: 8.6 mm, TL: 137 mm and 273 chaetigers; B. Syntype 1 of Marphysa furcellata Crossland, 1903 (BNHM 1924.3.1.139) with L10: 6.3 mm, TL: 40 mm and 114 chaetigers; C. Syntype 1 of Marphysa macintoshi Crossland, 1903 (BNHM 1924.3.1.22-3) with L10: 8.1 mm, TL: 18.8 mm and 262 chaetigers. Dotted blue line in B indicates the organism is incomplete.

Marphysa teretiuscula resembles M. americana Monro, 1933, M. angelensis Fauchald, 1970, M. depressa (Schmarda, 1861a), M. emiliae Molina-Acevedo and Carrera-Parra, 2017, M. nobilis Treadwell, 1917, M. sanguinea (Montagu, 1913) and M. tripectinata Liu, Hutchings & Sun, 2017 in having reddish subacicular hooks, the presence of compound spinigers and the absence of subacicular limbate chaetae. However, M. teretiuscula has palmate branchiae with a short bottom-stem in the anterior region, contrary to M. americana, M. angelensis, M. depressa, M. emiliae, M. nobilis and M. sanguinea which have pectinate branchiae throughout the body. Furthermore, M. teretiuscula has compound spinigers in all chaetigers, while in M. depressa, the spinigers are restricted to the anterior region. In addition, M. teretiuscula has the postchaetal lobe rounded in the first three chaetigers, while it is conical in the first three parapodia of M. americana and digitiform in M. angelensis, M. depressa, M. emiliae and M. sanguinea. Moreover, M. teretiuscula has distinctly longer branchial filaments than in M. angelensis. Additionally, M. teretiuscula has the subacicular hook as wide as the acicula, in contrast to that half as wide as acicula in M. nobilis and M. tripectinata. The comparison of M. teretiuscula with similar species is provided in Table 2.

Table 2.

Morphological features of Marphysa species with reddish subacicular hook and three types of pectinate chaetae. Abbreviations: MF: Maxillary formula, roman numerals refer to number of maxilla; MxC: maxillary carriers; CIS: closing system; COp: cavity opening; PR-I: first peristomial ring; PR-II: second peristomial ring; Chaet: chaetiger; p/a: present/absent; AR: anterior region; MR: median region; PR: posterior region; SH: subacicular hook. INSS: Isodont narrow with short and slender teeth; INLS: Isodont narrow with long and slender teeth; INLT: Isodont narrow with long and thick teeth; IWSS: Isodont wide with short and slender teeth; IWLS: Isodont wide with long and slender teeth; IWLT: Isodont wide with long and thick teeth; AWLT: Anodont wide with long and thick teeth; AWLS: Anodont wide with long and slender teeth.

Morphological feature M. americana Monro, 1933 M. angelensis Fauchald, 1970 M. depressa (Schmarda, 1861a) M. emiliae Molina-Acevedo & Carrera-Parra, 2017 M. nobilis Treadwell, 1917 M. sanguinea (Montagu, 1913) M. teretiuscula (Schmarda, 1861a) M. tripectinata Liu, Hutchings & Sun, 2017
Source of information holotype BNHM 1932.12.24.554-556 holotype LACM-AHF POLY 285; and additional material syntypes NHM
1044
holotype ECOSUR0180; paratype ECOSUR0181 holotype AMNH VI–1915–1350, additional material neotype BNHM 1867.1.7.24; additional material syntypes NHM 1092, M. simplex Crossland, 1903 syntypes BNHM 1937.9.2.325 paratypes AM W.49071, AM W.49072
Size (mm): L10, W10 12, 5.8 2.1–5.4, 17 4.2–11.5, 1.9–4.8 3.5, 1.6 6 –13.6, 6.5 11.5–20.4, 7.2–11 5.5–12.4; 0.8–5 11–12.3, 4–5
Prostomium: shape bilobed bilobed bilobed bilobed bilobed bilobed bilobed bilobed
Palps: reaching PR–I PR–II, Chaet 1 PR–I, Chaet 1 PR–II PR–I, PR–II PR–I, PR–II PR–I, Chaet 1 PR–II
Lateral antennae: reaching PR–II PR–II, Chaet 2 Chaet 1, 2 Chaet 1 PR–II, Chaet 2 PR–II, Chaet 1 Chaet 1 Chaet 1
Median antennae: reaching Chaet 1 Chaet 1, 3 Chaet 1, 3 Chaet 1 Chaet 1, 3 PR–II, Chaet 2 Chaet 1, 2 Chaet 1, 2
Peduncle in prostomial appendages absent absent absent absent absent absent absent absent
Eyes present present present present present present present present
MF: MII, MIII, MIV 5+4, 7+0, 3+9 3–5+4–5, 4–6, 3–4+6–8 3–4+4, 4–5, 3–5+6–8 4+4, 5+0, 3+8 3–4+3–4, 5–6, 3–4+7–8 4+4–5, 5–6, 3–4+6–8 4–6+4–7, 5–8, 4–5+7–9 5+5–6, 7, 4–5+8
MI vs. MxC: proportion 3.2× longer than MxC 2.1–3.4× longer than MxC 2–2.8× longer than MxC 2.5× longer than MxC 3.8× longer than MxC 2.9–3.2× longer than MxC 3–3.1× longer than MxC 2.6–2.8× longer than MxC
MI vs. CIS: proportion 5× longer than CIS 3–4.5× longer than CIS 3.5–4× longer than CIS 4.8× longer than CIS 5× longer than CIS 3.8–5.6× longer than CIS 4.4–5.5× longer than CIS 4–4.5× longer than CIS
MII vs COp: proportion 3× longer than COp 4.3–6× longer than COp 3.1–5× longer than COp 3.5× longer than COp 3.2× longer than COp 3.7–4.4× longer than COp 2.7–3.4× longer than COp 3.6–3.8× longer than COp
Branchiae: shaped pectinate pectinate pectinate pectinate pectinate pectinate palmate/pectinate palmate/pectinate
Branchiae: start chaetiger; last chaetiger before pygidium 45; 28 9–14; 3–31 26–44; 20–39 8–12; 10–13 17–27; 34–37 21–25; 9–18 18–32; 7–12 13–20; 16
Branchial filaments: numbers, length of the filaments 12, long 2–6, short 2–4, long 2–5, long 4–6; long 5–6; long 4–6; long 5–6; long
Dorsal cirri: shape conical conical conical AR, MR: conical, PR: digitiform AR: digitiform, MR: digitiform with swollen base, PR: conical conical conical AR: digitiform, MR, PR: conical
Prechaetal lobe: shape transverse fold transverse fold transverse fold transverse fold AR, MR, PR: transverse fold AR, MR, PR: transverse fold AR: dorsal edge longer, MR, PR: transverse fold AR: dorsal edge longer, MR, PR: transverse fold
Chaetal lobe: shape AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular AR: rounded, MR, PR: triangular
Developed postchaetal lobe: end chaetiger 92 18–61 27–60 42 39–71 50–70 20–56 50–131
Poschaetal lobe: shape in body regions Chaet 1–4: conical; from Chaet 5: rounded Chaet 1–4: digitiform, from Chaet 5: rounded Chaet 1–4: digitiform, from Chaet 5: auricular Chaet 1–4: digitiform, from Chaet 5: rounded rounded Chaet 1–4: digitiform, from Chaet 5: ovoid ovoid dorsal edge longer rounded with dorsal edge longer
Ventral cirri in first chaetigers: shape digitiform digitiform rounded digitiform conical digitiform conical conical
Ventral cirri with swollen base: start chaetiger; last chaetiger before pygidium 5; 45 4–7; 28–58 5–6; 22–28 4–7; 39–44 10–11; 44 5–8; 8–18 4–8; 34–68 6–8; 151
Ventral cirri in most posterior chaetigers: shape conical digitiform conical digitiform conical conical digitiform conical
Aciculae: shape; colour blunt, dark blunt, dark blunt, dark blunt, dark blunt, dark blunt, dark blunt, dark blunt, dark
Subacicular limbate chaetae absent absent absent absent absent absent absent absent
Pectinate chaetae: type in AR; MR, PR INLS; IWSS, IWLT, AWLT INST; IWSS, AWLS INSS; IWLT, AWLT IWSS; AWLT INLS; IWSS, AWLS INLS; IWSS, AWLS INLS; INLS, IWLT, AWLT INLS; IWLS, AWLS
Pectinate chaetae: number per type 3–4; 3–4, 2–3, 1–2 1–2; 3–4, 2–3 2–3; 3–4, 3–4 6–8; 3–4 2–3; 10–12, 6–7 1–2; 18–20, 4–5 1–2; 20–25, 3–4, 2–3 1–2; 16–17, 4–5
Pectinate chaetae teeth: number per type 12; 16, 16, 11 15; 18, 8–9 8–9; 14, 13–14 20–22; 13 16–17; 17, 16 10; 18, 10–12 21–22; 30–32, 16–18, 6–7 18; 25, 15–17
Spiniger blade: length in AR 2 lengths 2 lengths similar length 2 lengths 2 lengths 2 lengths 2 lengths 2 lengths
Spiniger blade: length in MR-PR similar length 2 lengths - 2 lengths 2 lengths 2 lengths 2 lengths 2 lengths
Spiniger: distribution all chaet all chaet AR only all chaet all chaet all chaet all chaet all chaet
Falciger: (p/a); distribution a; NA p; all chaet or AR p; all chaet p; AR absent absent absent absent
Subacicular hook: start chaetiger 117 14–29 33–68 21–28 31–94 74–286 30–38 62–115
Subacicular hook: shape; colour bidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally unidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally bidentate, reddish basally and translucent distally
Width acicula vs. SH in MR-PR: proportion similar width similar width similar width similar width Acicula 2× wider than SH Acicula 2× wider than SH similar width Acicula 2× wider than SH
Subacicular hook: distribution discontinuous continue continue continue discontinuous discontinuous discontinuous continuous

Discussion

Marphysa group without compound chaetae

At present, the small Marphysa group A proposed by Fauchald (1970) consists of four species characterised by the absence of compound chaetae: Marphysa mossambica from Mozambique, M. novaehollandiae from Sydney, M. moribidii from Malaysia and M. fijiensis nom. nov. from Fiji. All these species are represented by large organisms with a high number of segments (more than 200) in the adult stage. However, the ontogenetic development of these species and the presence of compound chaetae in the early stages, a common condition in other Marphysa species (Southern 1921; Aiyar 1931; Pillai 1958), are unknown.

The absence of compound chaetae was an important character to consider the species in the Marphysa group A as an independent genus, Nauphanta Kinberg, 1865 (Fauchald 1987). However, Glasby and Hutchings (2010) regarded Nauphanta as a junior synonym of Marphysa, based on the variation in that feature in ontogeny. In addition, Zanol et al. (2014) supported this synonymy in a phylogenetic analysis of Eunicidae, based on morphological and molecular evidence, confirming this uncommon condition is developed in some Marphysa species.

The emergence of compound chaetae in the early stages has been well documented in some Marphysa species from India: Marphysa borradailei (Borradaile 1902; Pillai 1958), M. gravelyi (Malathi et al. 2011) and Marphysa sp. (Aiyar 1931). During the development of the first chaetiger in the metatrochophore larvae of these species, the first compound chaeta is characterised by having convex and straight edges as they emerge (Borradaile 1902; Southern 1921; Aiyar 1931; Pillai 1958) just after the appearance of two unjointed (simple) chaetae (Borradaile 1902; Aiyar 1931; Malathi et al. 2011). This compound chaeta resembles the blade of the compound falciger, although it lacks the typical distal teeth. When the third chaetiger is developed, only the same compound chaeta emerges in chaetigers 2 and 3 (Borradaile 1902; Southern 1921; Aiyar 1931; Pillai 1958). At the time of development of chaetigers 12–13, two types of compound chaetae can be observed (Aiyar 1931; Pillai 1958): (1) a hooked chaeta, herein judged as the compound falciger; and (2) a sickle-shaped chaeta, also called falcigerous by Aiyar (1931) and Pillai (1958), herein interpreted as the typical compound spiniger.

Aiyar (1931) also described the shift and loss of chaetae in larger specimens of Marphysa sp. The specimens have limbate chaetae throughout the body regardless of size, in contrast to the compound chaetae lost to different extents. The compound spinigers are present in all chaetigers in specimens with up to 150 chaetigers, but they disappear in the most-posterior chaetigers in larger specimens; on the contrary, the compound falcigers appear only in the posterior region of specimens with 70–80 chaetigers and entirely disappear in specimens with 150 or more chaetigers.

Glasby and Hutchings (2010) indicated that the lack of compound falcigers in Marphysa is due to their loss during the transition from juvenile to young adults, as occurs in M. angelensis Fauchald, 1970 (Molina-Acevedo and Villalobos-Guerrero, in prep.), M. borradailei (Southern 1921; Pillai 1958), M. brevitentaculata Treadwell, 1921 (Salazar-Vallejo and Carrera-Parra 1998; Molina-Acevedo and Carrera-Parra 2017), M. gravelyi (Southern 1921; Pillai 1958) and M. sherlockae Kara et al. 2020 (Kara et al. 2020). Likewise, Glasby and Hutchings (2010) stated that the absence of compound spinigers is a paedomorphic condition in Marphysa group A since they are supposedly lacking in the juveniles. However, it contradicts the evidence demonstrated by Aiyar (1931) and Pillai (1958) for juveniles of Marphysa sp. and M. borradailei having compound spinigers.

The absence of both compound spinigers and falcigers in species of Marphysa group A is more likely due to their gradual loss as the body of the specimens increases in size. The small juveniles have both compound spinigers and falcigers, but the latter chaetae begin to disappear as the animal grows. In juveniles or young adults, the falcigers may be lost entirely, with the compound spinigers being replaced by limbate chaetae. Finally, in adults, both compound spinigers and falcigers may be lacking. Several suitable examples allude to this chaetal transition. For instance, in the group with limbate subacicular chaetae sensu Glasby and Hutchings (2010, see below), the adults have compound spinigers in the anterior-median region, which are replaced by limbate chaetae in the median-posterior. Likewise, in M. brevitentaculata, M. digitibranchia Hoagland, 1920 and M. mangeri Augener, 1918, the compound falcigers are present solely in the anterior region, the compound spinigers only in the anterior-median region and limbate subacicular chaetae only in median-posterior region (Augener 1918; Hoagland 1920; Molina-Acevedo and Carrera-Parra 2017). To confirm this hypothesis, a thorough ontogenetic study on the chaetal shift is needed to understand the absence of compound chaetae in Group A.

Marphysa teretiuscula, a misinterpreted species

Marphysa teretiuscula has received little attention since Schmarda (1861a) described it initially from the east coast of Sri Lanka (formerly Ceylon). Although de Quatrefages (1866), Ehlers (1868) and Crossland (1903) recognised the species as valid in Marphysa, it was overlooked by some authors who extensively studied the polychaetous annelids from India, such as Gravely (1927) and Fauvel (1930, 1932, 1940, 1953). Marphysa teretiuscula was briefly mentioned in the early 1900s when Borradaile (1902) described the larval development of specimens from the north of Sri Lanka that release the embryos in jelly cocoons attached to the bottom by a stem. One of these worms was identified by Arthur Willey as allied to, or identical with, M. teretiuscula (see Borradaile 1902), the only species known at that time from the area. Later, Southern (1921) and Aiyar (1931) found a specimen with similar reproductive patterns to those described by Borradaile, which were identified as M. gravelyi (Southern) from the Chilka Lake and Marphysa sp. from Madras. Pillai (1958) studied the specimens from the Negombo Lagoon, Sri Lanka, which also fitted in terms of ontogeny to M. teretiuscula sensu Borradaile (1902), but differed from Schmarda’s original description in several morphological respects. In this regard, Pillai (1958) described these specimens as a new species, M. borradailei. Regrettably, the reproduction and development of M. teretiuscula are still unknown.

Marphysa teretiuscula was chosen by Glasby and Hutchings (2010) to create the informal ‘Teretiuscula-group’ within Marphysa, which is featured by having species with compound spinigers restricted to anterior chaetigers and subacicular limbate chaetae present throughout the body, in addition to the formation of jelly cocoons as part of a reproductive strategy. The species included in the ‘Teretiuscula-group’ are M. fauchaldi, M. borradailei, M. gravelyi, M. teretiuscula (Glasby and Hutchings 2010) and the recently described species, M. madrasi (Hutchings et al. 2020). However, the stem species M. teretiuscula, in fact, lacks those relevant features encompassing the ‘Teretiuscula-group’. As demonstrated in the present study’s re-description, M. teretiuscula bears compound spinigers only and lacks subacicular limbate chaetae in all parapodia (Fig. 7E, F). Furthermore, the reproduction of M. teretiuscula is unknown compared with those species from the same region, M. borradailei and M. gravelyi. Herein, we judge M. teretiuscula as belonging to the group B2 sensu Fauchald (1970), whereas the ‘Teretiuscula-group’ sensu Glasby and Hutchings (2010) is renamed with the earliest species described within, ‘Gravelyi-group’.

Two other species have also been described from near the type locality of M. teretiuscula: Paramarphysa orientalis Willey, 1905 and M. chevalensis Willey, 1905, both from the Gulf of Manaar (India). The first species is recently considered indeterminable by Molina-Acevedo and Idris (accepted, but not yet published), while the second species is here treated in the same manner. Marphysa chevalensis was described, based on two specimens: the smaller has both compound falcigers and spinigers in all chaetigers, whereas the larger has a similar chaetal pattern; however, the falcigers are restricted to the anterior-median region (Willey 1905). The larger specimen could have undergone a loss of falcigers as demonstrated in the young adults of M. gravelyi, M. brevitentaculata and M. sherlockae (Southern 1921; Pillai 1958; Salazar-Vallejo and Carrera-Parra 1998; Kara et al. 2020). Marphysa chevalensis may be the young adult of one of the species described from Sri Lanka or India (M. gravelyi, M. borradailei and M. teretiuscula) that has not yet developed its adult complement of chaetae. On the other hand, the type material of M. chevalensis is lost and relevant diagnostic characters, such as the shape of parapodia, the maxillary formula, the presence of subacicular limbate chaetae, the colour of the subacicular hook, among others, were not included in the original description. This lack of information hinders the differentiation between similar species, even when fresh topotype material is available. Therefore, we also consider M. chevalensis as an indeterminable species.

Conclusion

In the present work, we clarified the taxonomic status of five Marphysa species. The synonymy of M. teretiuscula over M. simplex Crossland was confirmed and the re-description of the species was provided using the type material. Marphysa simplex Treadwell was re-established, re-described and a new name for this homonym species was proposed, M. fijiensis nom. nov. Likewise, M. simplex (Langerhans), M. chevalensis and Paramarphysa orientalis were considered indeterminable.

On the other hand, the informal groups (B2, C and D) into which Marphysa has been split, have not yet been monophyletically tested. These divisions are used here to highlight the diversity of forms within the genus and help differentiate the species morphologically. However, it is imperative to carry out a species revision and a phylogenetic analysis to help reveal these artificial groups’ status.

Historically, many synonyms have been subjectively proposed for Marphysa species causing a simultaneous decline in the species richness and an increase in either cosmopolitan species or species complexes. We strongly recommend that, before establishing a new synonymy, researchers should rely on the review of the type material of the species in question to describe it in detail, including the overlooked characters and to compare the species for distinguishing them accurately and ideally collecting fresh material from the type locality for molecular work and morphological variation.

Acknowledgements

The authors thank Mark Siddall, Lily Berniker (AMNH), Stephen Keable, Helen Stoddart (AM), Emma Sherlock (BMNH), Helmut Sattmann (NHM), Karen Osborn, Kathryn Ahlfeld, Karen Reed, Chad Walter (USNM), Birger Neuhaus (ZMB) and technicians and laboratory assistants in the collections for making available the materials that made this study possible. To El Colegio de la Frontera Sur and INOS of Universiti Malaysia Terengganu, Luis F. Carrera Carrera-Parra and Sergio I Salazar-Vallejo for their support and by allowing the first author the use of installations for data analysis. To Tulio F. Villalobos-Guerrero for the comments to improve the manuscript and taxonomic advice. Thanks go to Humberto Baena-Basave (ECOSUR) for his advice on digital photography and photo editing. We are also grateful to editor Pavel Stoev and the five reviewers for their careful comments and suggestions. During this research, the first author was supported by a scholarship from CONACYT (514117/298079) and DAAD Short-Term Grants (91673476).

References

  • Augener H (1918) Polychaeta. Beitrage zur Kenntnis der Meeresfauna Westafrikas 2(2): 67–625.
  • Berthold AA (1827) Latreille’s Natürliche Familien des Thierreichs: Aus dem Franzosischen, mit Anmerkungen und Zusätzen. Verlage Landes-Industrie-Comptoirs, Weimar, 606 pp. https://doi.org/10.5962/bhl.title.11652
  • Crossland C (1903) On the marine fauna of Zanzibar and British East Africa, from collections made by Cyril Crossland in the years 1901 and 1902. Polychaeta. Part I. Proceedings of the Zoological Society of London 73(1): 169–176. https://doi.org/10.1111/j.1469-7998.1903.tb08273.x
  • Day JH (1957) The Polychaeta Fauna of South Africa. Part 4. New species and records from Natal and Moçambique. Annals of the Natal Museum 14(1): 59–129.
  • de Quatrefages A (1865) Note sur la classification des Annélides. Compte rendu hebdomadaire des séances de l’Academie des science 60: 586–600.
  • de Quatrefages A (1866) [1865] Histoire Naturelle des Annelés Marins et d’Eau Douce: Annélides et Géphyriens. Tome Premier. Collection des Suites a Buffon formant avec les Oeuvres de cet auteur un Cours Complet d’Histoire Naturelle. Librairie Encyclopédique de Roret, Paris, 588 pp. [Wright, E.P. (1866) Annelida. Zoological Record, Section 6 (Annelida etc.), 578–600 pp] https://doi.org/10.5962/bhl.title.122818
  • Ehlers E (1868) Die Borstenwürmer (Annelida Chaetopoda) nach systematischen und anatomischen Untersuchungen dargestellt. Verlag von Wilhelm Engelmann, Leipzig, 269–748 pp.
  • Fauchald K (1970) Polychaetous annelids of the families Eunicidae, Lumbrineridae, Iphitimidae, Arabellidae, Lysaretidae and Dorvilleidae from Western Mexico. Allan Hancock Monographs in Marine Biology 5: 1–335.
  • Fauchald K (1987) Redescription of the genus Nauphanta Kinberg, 1865 (Polychaeta: Eunicidae). Proceedings of the Biological Society of Washington 100(2): 375–380.
  • Fauvel P (1919) Annélides Polychètes de Madagascar, de Djibouti, et du Golfe Persique. Archives de zoologie expérimentale et générale 58: 315–473. https://doi.org/10.5962/bhl.part.8154
  • Fauvel P (1930) Supplement to the Littoral Fauna of Krusadai Island in the Gulf of Manaar. Part 1. Annelida Polychaeta of the Madras Government Museum. Bulletin of the Madras Government Museum, new series, Natural History section 1(2): 1–72.
  • Fauvel P (1932) Annelida Polychaeta of the Indian Museum, Calcutta. Memoirs of the Indian Museum 12(1): 1–262.
  • Fauvel P (1940) On a small collection of Annelida Polychaeta of the Indian Museum, Calcutta. Record of the Indian Museum 422: 253–568.
  • Fauvel P (1953) The fauna of India including Pakistan, Ceylon, Burma and Malaya: Annelida, Polychaeta. The Indian Press Ltd., Allahabad, 507 pp.
  • Glasby CJ, Hutchings PA (2010) A new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicida: Eunicidae) from northern Australia and a review of similar taxa from the Indo-west Pacific, including the genus Nauphanta Kinberg, 1865. Zootaxa 2352: 29–45. https://doi.org/10.11646/zootaxa.2352.1.2
  • Gravely FH (1927) The littoral fauna of Krusadai Island in the Gulf of Manaar. Chaetopoda. Bulletin of the Madras Government Museum, new series, Natural History Section 1(1): 55–86.
  • Grube AE (1878) Untersuchungen ueber die Familie Eunicea. Naturwissenschaftliche Schriften Gesellschaft, Berlin 1878: 37–62.
  • Hartman O (1949) The marine annelids erected by Kinberg. With some notes on some other types in the Swedish State Museum. Arkiv för Zoologi 42A(1): 1–137.
  • Hartman O (1956) Polychaetous annelids erected by Treadwell, 1891 to 1948, together with a brief chronology. Bulletin of the American Museum of Natural History 109(2): 239–310.
  • Hartman O (1959) Catalogue of the Polychaetous Annelids of the World. Parts 1 and 2. Allan Hancock Foundation Occasional Paper 23: 1–628.
  • Hoagland RA (1920) Polychaetous annelids collected by the United States fisheries steamer Albatross during the Philippine expedition of 1907–1909. Bulletin of the United States National Museum 100(1): 603–635.
  • Hutchings P, Lavesque N, Priscilla L, Daffe G, Malathi E, Glasby C (2020) A new species of Marphysa (Annelida: Eunicida: Eunicidae) from India, with notes on previously described or reported species from the region. Zootaxa 4852(3): 285–308. https://doi.org/10.11646/zootaxa.4852.3.2
  • Idris I, Hutchings P, Arshad A (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: 109–121. https://doi.org/10.24199/j.mmv.2014.71.11
  • ICZN [International Commission on Zoological Nomenclature] (1999) International Code Of Zoological Nomenclature (4th edn.). The International Trust for Zoological Nomenclature, London.
  • Kara J, Molina-Acevedo IC, Zanol J, Simon C, Idris I (2000) Morphological and molecular systematic review of Marphysa Quatrefages, 1865 (Annelida: Eunicidae) species from South Africa. PeerJ 8: e10076. http://doi.org/10.7717/peerj.1007
  • Kinberg JGH (1865) Annulata nova. Öfvers K VetenskAkad Förh Stockh 21: 559–574.
  • Langerhans P (1884) Die Wurmfauna von Madeira. IV Zeitschrift für wissenschaftliche Zoologie 40(2): 247–285.
  • Liu Y, Hutchings PA, Sun S (2017) Three new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicida: Eunicidae) from the south coast of China and redescription of Marphysa sinensis Monro, 1934. Zootaxa 4263: 228–250. https://doi.org/10.11646/zootaxa.4377.2.3
  • Liu Y, Hutchings PA, Kupriyanova E (2018) Two new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicida: Eunicidae) from northern coast of China and redescription for Marphysa orientalis Treadwell, 1936. Zootaxa 4377: 191–215. https://doi.org/10.11646/zootaxa.4377.2.3
  • Malathi E, Sunder Raj SK, Mercy BP (2011) Larval development of Marphysa gravelyi (Polychaeta: Eunicidae) from Pulicat Lake, India. Italian Journal of Zoology 78(Supplement 1): 249–254. https://doi.org/10.1080/11250003.2011.589173
  • Molina-Acevedo IC (2018) Morphological revision of the Subgroup 1 Fauchald, 1970 of Marphysa de Quatrefages, 1865 (Eunicidae: Polychaeta). Zootaxa 4480(1): 1–125. https://doi.org/10.11646/zootaxa.4480.1.1
  • Molina-Acevedo IC, Carrera-Parra LF (2015) Reinstatement of three Grand Caribbean species of the Marphysa sanguinea complex (Polychaeta: Eunicidae). Zootaxa 3925: 37–55. https://doi.org/10.11646/zootaxa.3925.1.3
  • Molina-Acevedo IC, Carrera-Parra LF (2017) Revision of Marphysa de Quatrefages, 1865 and some species of Nicidion Kinberg, 1865 with the erection of a new genus (Polychaeta: Eunicidae) from the Grand Caribbean. Zootaxa 4241: 1–62. https://doi.org/10.11646/zootaxa.4241.1.1
  • Molina-Acevedo IC, Idris I (2020) Reinstatement of species belonging “Marphysa sanguinea complex” (Annelida: Eunicidae) and description of new species from the mid-Pacific Ocean and the Adriatic Sea. Zootaxa 4816(1): 1–48. https://doi.org/10.11646/zootaxa.4816.1.1
  • Molina-Acevedo IC, Idris I (accepted) Revision of abranchiate species of Marphysa de Quatrefages, 1865 and their transference to Nicidion Kinberg, 1865 (Eunicidae: Annelida) with redescription of the type species N. cincta Kinberg, 1865. Marine Biodiversity.
  • Monro CCA (1933) The Polychaeta Errantia collected by Dr. C. Crossland at Colón, in the Panama Region, and the Galapagos Islands during the expedition of the S.Y. “St. George”. Proceedings of the Zoological Society of London 1933: 1–196. https://doi.org/10.1111/j.1096-3642.1933.tb01578.x
  • Pillai TG (1958) Studies on a brackish-water polychaetous annelid, Marphysa borradailei sp. n. from Ceylon. Ceylon Journal of Science, Biological Sciences 1(2): 94–106.
  • Salazar-Vallejo SI, Carrera-Parra LF (1998) Eunícidos (Polychaeta) del Caribe mexicano con claves para las especies del Gran Caribe: Fauchaldius, Lysidice, Marphysa, Nematonereis y Palola. Revista de Biología Tropical 45: 1481–1498.
  • Schmarda LK (1859) Neue wirbellose Tiere beobachtet und gesammelt auf einer Reise um die Erde 1853 bis 1857. Erster Band: Neue Turbellarien, Rotatorien und Anneliden. Erste Hälfte. Wilhelm Engelmann, Leipzig, 66 pp. https://doi.org/10.5962/bhl.title.85313
  • Schmarda LK (1861a) Neue wirbellose Thiere beobachtet und gesammelt auf einer Reise un die Erdr 1853 bis 1857. Erster Band (zweite halfte) Turbellarian, Rotatorien un Anneliden 2: 1–164.
  • Schmarda LK (1861b) Reise um die Erde in den Jahre 1853–1857. George Westermann, Braunschweig (Brunswick), Vol. 1, 592 pp.
  • Southern R (1921) Polychaeta of the Chilka Lake and also of fresh and brackish waters in other parts of India. Memoirs of the Indian Museum 5: 563–659.
  • Treadwell AL (1922) Leodicidae from Fiji and Samoa. Carnegie Institute of Washington Publication 312: 127–170.
  • Villalobos-Guerrero TF (2019) Redescription of two overlooked species of the Perinereis nuntia complex and morphological delimitation of P. nuntia (Savigny in Lamarck, 1818) from the Red Sea (Annelida, Nereididae). Zoosystema 41(24): 465–496. https://doi.org/10.5252/zoosystema2019v41a24
  • Willey A (1905) Report on the Polychaeta collected by Professor Herdman, at Ceylon, in 1902. Report to the Government of Ceylon on the Pearl Oyster Fisheries of the Gulf of Manaar by W.A. Herdman, with supplementary reports upon the Marine Biology of Ceylon, by Other Naturalists. Part IV. Supplementary Reports 30: 243–324.
  • Zanol J, Halanych KM, Fauchald K (2014) Reconciling taxonomy and phylogeny in the bristleworm family Eunicidae (Polychaete: Annelida). Zoologica Scripta 43: 79–100. https://doi.org/10.1111/zsc.12034
  • Zanol J, da Silva TDSC, Hutchings PA (2016) Marphysa (Eunicidae, polychaete, Annelida) species of the Sanguinea group from Australia, with comments on pseudo-cryptic species. Invertebrate Biology 135: 328–344. https://doi.org/10.1111/ivb.12146

Supplementary material

Supplementary material 1 

Template for primary biodiversity data of Marphysa species

Isabel Cristina Molina-Acevedo, Izwandy Idris

Data type: template

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
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