Research Article |
Corresponding author: Isabel Cristina Molina-Acevedo ( imolina@ecosur.edu.mx ) Academic editor: Pavel Stoev
© 2021 Isabel Cristina Molina-Acevedo, Izwandy Idris.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Molina-Acevedo IC, Idris I (2021) Unravelling the convoluted nomenclature of Marphysa simplex (Annelida, Eunicidae) with the proposal of a new name and the re-description of species. Zoosystematics and Evolution 97(1): 121-139. https://doi.org/10.3897/zse.97.59559
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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.
Homonymy, limbate chaetae, morphological review, synonymy, type material
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
The name M. simplex was firstly used by
About two decades later,
Later, a third species with the same name appeared as a secondary homonym (
The three species named M. simplex differ in morphology and can be classified into three of the informal groups proposed by
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.
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 (
The materials reviewed in this study were deposited in the following institutions: American Museum of Natural History, New York, USA (
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
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).
Order Eunicida Dales, 1962
Family Eunicidae Berthold, 1827
Genus Marphysa de Quatrefages, 1865
Marphysa simplex
Treadwell, 1922: 151–152, pl. 5, figs 8–12, text-figs 39 (non Crossland, 1903); –
Holotype. Fiji · Suva Harbour; Apr–Jun, 1920;
Eunice mossambica Peters, 1854
Mozambique · one specimen and vial with six parapodia; lectotype
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
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.
The new name denotes the geographic region where the specimen was collected.
Holotype complete (Fig.
Prostomium bilobed, 1.3 mm long, 1.6 mm wide; lobes frontally rounded; median sulcus shallow and deep ventrally (Fig.
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.
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
Marphysa fijiensis nom. nov., holotype (
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.
Aciculae blunt, basally reddish and translucent distally; colourless in posterior chaetigers (Fig.
Marphysa fijiensis nom. nov., holotype (
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.
Pygidium with two pairs of anal cirri broken (Fig.
Known only from the type locality.
Uncertain. Possibly coral reefs or mudflats (
The first comment on the synonymy of Marphysa fijiensis nom. nov. (as M. simplex Treadwell, 1922) and M. mossambica was made by
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
Morphological features of Marphysa group A sensu
Morphological feature | M. moribidii Idris et al., 2014 | M. mossambica (Peters, 1854) | M. novaehollandiae (Kinberg, 1865) | M. fijiensis nom. nov. |
---|---|---|---|---|
Source of information | paratypes |
lectotype |
holotype SMNH-type-432; |
holotype |
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 |
Eunice teretiuscula
Schmarda, 1861a: 129, pl. 32, fig. 59, text-figs a–d, f, OK, UK;
Marphysa teretiuscula
–
Marphysa simplex Crossland, 1903: 140–141, pl. 15, figs. 11–12, text-fig. 13.
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
Marphysa simplex Crossland, 1903
Zanzibar · two adult specimens; 11 Jan 1934; Murray Exped. St. 104, Petersen Grab, V.310, 207 m; syntypes
Marphysa teretiuscula (Schmarda, 1861a)
Mozambique · two specimens; Morrumbene Estuary; 16 Jan 1954;
India · one specimen; Ratnagiri Creek, Shirgaon, Maharashtra; 17°17'13.78"N, 73°17'13.87"E; 18 Apr 1994;
Marphysa furcellata Crossland, 1903
Zanzibar · two specimens; 1901; between tidemarks, 27.4 m; C. Crossland leg.; syntypes
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
Syntype NHM type 1092 incomplete, gravid female, with 210 chaetigers, L10 = 9.3 mm, W10 = 5 mm TL = 860 mm (Fig.
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 (
Prostomium bilobed, 4 mm long, 2.5 mm wide; lobes frontally rounded; median sulcus (Fig.
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.
Maxillary apparatus with MF = 1+1, 4+4, 5+0, 5+7, 1+1 (Fig.
Branchiae from chaetiger 32, with up to five long filaments; with two forms: palmate with short button-shaped branchial stem in anterior chaetigers (Fig.
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 (
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.
Aciculae blunt, basally reddish and translucent distally (Fig.
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.
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 (
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.
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.
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).
Sri Lanka, Maharashtra (India), Zanzibar.
Unknown.
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.
Distribution of branchial filaments throughout the body. A. Syntype 1 of Marphysa simplex Crossland, 1903 (
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
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 |
holotype LACM-AHF POLY 285; and additional material | syntypes NHM 1044 |
holotype ECOSUR0180; paratype ECOSUR0181 | holotype |
neotype |
syntypes NHM 1092, M. simplex Crossland, 1903 syntypes |
paratypes |
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 |
At present, the small Marphysa group A proposed by
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 (
The emergence of compound chaetae in the early stages has been well documented in some Marphysa species from India: Marphysa borradailei (
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
Marphysa teretiuscula has received little attention since
Marphysa teretiuscula was chosen by
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 (
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.
The authors thank Mark Siddall, Lily Berniker (
Template for primary biodiversity data of Marphysa species
Data type: template