Zoosyst. Eval97 (1) 2021, 121-139" || DOl 10.3897/28e.97.59559 yee BERLIN Unravelling the convoluted nomenclature of Marphysa simplex (Annelida, Eunicidae) with the proposal of a new name and the re-description of species Isabel Cristina Molina-Acevedo!*, Izwandy Idris? 1 Estructura y Funcion del Bentos, Depto. Sistemdtica y Ecologia Acudtica, El Colegio de la Frontera Sur, Chetumal, Quintana Roo, Mexico 2 South China Sea Repository and Reference Centre, Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia http://zoobank.org/94AF3450-CEAF-4F0C-8149-C3F9BAIE405A Corresponding author: Isabel Cristina Molina-Acevedo (isacrismoliace@gmail.com) Academic editor: Pavel Stoev # Received 11 October 2020 Accepted 21 January 2021 Published 10 February 2021 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 rede- scription on M. teretiuscula is also given. Key Words Homonymy, limbate chaetae, morphological review, synonymy, type material Introduction The name M. simplex was firstly used by Crossland (1903) for two specimens from Zanzibar (Tanzania). Al- Within the long story of Marphysa de Quatrefages, 1865, the name M. simplex has been referred to in sev- eral 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 tax- onomic issues. though 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 anew species, M. simplex, based on one specimen found together with MZ macintoshi Crossland, 1903 in Suva Copyright /sabel C. 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. 22 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex Harbour, Fiji. Even though Treadwell knew about Cross- land’s contributions, it is uncertain why he used an al- ready 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 spec- imen from Madeira (Portugal). Amphiro Kinberg, 1865 was considered a junior synonym of Marphysa by Hart- man (1949); therefore, the species described in that genus became part of Marphysa, including Langerhans’ species. The three species named M. simplex differ in morphol- ogy and can be classified into three of the informal groups proposed by Fauchald (1970). Crossland’s specimens be- long 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 diagnos- tic 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 homony- mies, considered M. simplex Crossland a junior synonym of M. teretiuscula following Crosland’s comments re- garding the similarity and also because the body shape and the length of the peristomial appendages were consis- tent between both species. Likewise, Glasby and Hutch- ings (2010) synonymised M. simplex Treadwell with M. mossambica (Peters, 1854) because the only differ- ences 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 MZ simplex Treadwell, as it is distin- guished 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 spini- gers and subacicular limbate chaetae (Glasby and Hutch- ings 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), zse.pensoft.net National Museum of Natural History, Smithsonian Insti- tution, Washington D.C., USA (USNM) and Museum of Natural History, Berlin, Germany (ZMB). The re-descriptions of species were illustrated with digi- tal photographs. A series of photos were stacked using Hel- iconFocus 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 appara- tus, parapodia, compound chaetae and simple chaetae. The terminology to describe the overall morphology of char- acters followed those recently provided by Molina-Ace- vedo 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 chae- tae were described according to Molina-Acevedo and Car- rera-Parra (2015, 2017) and Zanol et al. (2016), respective- ly. 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 dis- sected 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), ex- cluding parapodia, were used as a size estimate of an 1n- dividual 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. Further- more, for specimens from M. teretiuscula, linear regres- sion analyses were included to evaluate the relationships between L10, W10 and several morphological features, including the starting of branchiae and subacicular chae- tae 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 R? (e.g. R? = 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 1-4, 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. Fru - Suva Harbour; Apr—Jun, 1920; AMNH 1920-1530. Zoosyst. Evol. 97 (1) 2021, 121-139 123 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; KF. Pygidium, lateral view. Scale bars: 0.35 mm (A); 2 mm (B—D); 0.5 mm (E, F). Comparative material examined. Eunice mossambica Peters, 1854 Nauphanta novaehollandiae Kinberg, 1865 AUSTRALIA « one specimen divided into four vials, one MOZAMBIQUE « One specimen and vial with six parap- odia; 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 \dris, Hutchings & Arshad, 2014 Ma.aysIA - two adult specimens; Pantai Kelanang, Morib, Selangor; 2°45'39.85"N, 101°26'08"E; in man- grove vegetation; 19 Jul 2011; I. Idris leg.; paratype AM W.38690. of them with maxillary apparatus; Sydney Port Jack- son; 33°54'S, 151°11'E; Eugenie Epx. 1851-53; holo- type SMNH-type-432. Etymology. The new name denotes the geographic re- gion where the specimen was collected. Description. Holotype complete (Fig. 1A—F), ven- trally 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 zse.pensoft.net 124 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex Figure 2. Marphysa fijiensis nom. nov., holotype (AMNH 1920-1530). A. Chaetiger 3; B. Chaetiger 8; C. Chaetiger 14; D. Chaeti- ger 123; E. Chaetiger 188. Marphysa mossambica (Peters, 1854), lectotype (ZMB 4005a). F. Chaetiger 3; G. Chaetiger 8; H. Chae- tiger 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). zse.pensoft.net Zoosyst. Evol. 97 (1) 2021, 121-139 Number of branchial filaments 140 160 180 200 125 Ny wo fo DN ODO OO oOo — 0 100 200 300 400 Number of chaetigers 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. chaetiger 6 (Fig. 1D), widest at chaetiger 17, tapering after chaetiger 41. Prostomium bilobed, 1.3 mm long, 1.6 mm wide; lobes frontally rounded; median sulcus shallow and deep ven- trally (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, sep- aration 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. First two parapodia smaller; best developed in chae- tigers 4-21, following parapodia gradually decreas- ing 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 tn 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). Post- chaetal 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 dig- itiform 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 distal- ly; 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 acic- ulae; in chaetigers 25—43 with three aciculae; in chae- tigers 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). 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 slen- der 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 chae- tae not observed. Compound chaetae absent. Subacicular hooks starting from chaetigers 38R—39L, one per chaeti- ger, 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). zse.pensoft.net 126 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex 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 um (A, B, F, G); 12.5 um (C—E). 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 simi- lar to the smaller-sized specimens of Z mossambica. How- ever, after a detailed morphological comparison of both spe- cies’ type material, we found marked differences. Marphysa zse.pensoft.net 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 an- terior region and the postchaetal lobe is oval in the first three Zoosyst. Evol. 97 (1) 2021, 121-139 127 Table 1. Morphological features of Marphysa group A sensu Fauchald (1970). Abbreviations: MF: Maxillary formula, roman numer- als 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: sub- acicular 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 \dris et al., M. mossambica (Peters, 1854) M. novaehollandiae M. fijiensis nom. nov. 2014 (Kinberg, 1865) Source of information paratypes AM W. 38690; | lectotype ZMB 4005a; paralectotypes holotype SMNH- holotype AMNH additional material ZMB 47; ZMB F2046, ZMB 4005 type-432; AM W.33021 1920-1530 Size (mm): L10, W10 12.2-20, 6.3-8.2 8-11.5, 3.6-8.1 6.6-9.6, 44.2 S82 Prostomium: shape bilobed bilobed bilobed bilobed Palps: reaching PR-Il PR-lI or Chaet 1 PR-Il PR-Il Lateral antennae: reaching PR-lI 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 present absent absent absent appendages Eyes present absent MF: MII, MILI, MIV 5+5-6, 6-7, 3-44+8-9 5+5-6, 9, 2+8 MI vs. MxC: proportion MI vs. CIS: proportion 2.4—2.8x longer than MxC 2-3x longer than MxC 2.4-3.2x longer than ? MxC 4.3-5.7x longer than CIS 5-7x longer than CIS 4.4-8~x longer than CIS ‘4 MIl vs. COp: proportion 4.3-4.7x longer than COp 3.2-4x longer than COp 4.5-5.3x longer than ? COp Branchiae: shaped pectinate pectinate pectinate pectinate Branchiae: start chaetiger; 2/-39; 15-37 23-48; 29-126 21-25; 15 22; 3 last chaetiger before pygidium Branchial filaments: 7-10; long 7-8; long 6-7; long 5; long numbers; length of the filaments 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, rounded PR: rounded Developed postchaetal lobe: 50-96 27-70 32-38 55 end chaetiger Postchaetal lobe: shape in body regions Chaet 4-10, 10: rounded Chaet 4: digitiform short, | 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 digitiform digitiform digitiform digitiform chaetigers: shape (i eereer * | Ventral cirri with swollen 6; 62-96 7-9; 96-208 8; 41 14; 72 base: start chaetiger; last chaetiger before pygidium Ventral cirri in most conical conical conical conical posterior chaetigers: shape Aciculae: shape; colour blunt, dark Subacicular limbate chaetae: (p/a); distribution present; all chaet present; all chaet present; all chaet present; all chaet Pectinate chaetae: type in INLS; IWSS, IWLS, AWLT INLS; IWSS, IWLS, AWLT INLS; IWSS, IWLS, ? INSS; IWSS AR; MR, PR Pectinate chaetae: number 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 per type Pectinate chaetae teeth: 18; 52, 26, 7 18-19; 56, 27, 9-10 25; 50-51, 35; ? 16-18; 38-42 number per type Subacicular hook: start 56-65 35-65 39-42 38 chaetiger 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 2x wider than SH Acicula 2x wider than | Acicula 2x wider than SH SH Subacicular hook: discontinuous distribution chaetigers. In contrast, in. 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 discontinuous discontinuous discontinuous (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 con- trast, M. moribidii (L10: 12.2—20 mm) has a peduncle at the base of the palpo- and ceratostyles, bears ventral cirri zse.pensoft.net 128 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex with a swollen base starting from chaetiger 6 and has a subacicular hook similar in width to the acicula through- out 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 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 ante- rior 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. Marphysa teretiuscula (Schmarda, 1861a) Figures 5—9, Table 2 Eunice teretiuscula Schmarda, 1861a: 129, pl. 32, fig. 59, text-figs a—d, f, OK, UK; Grube 1878: 59. Marphysa teretiuscula — de 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 an- terior 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, Maha- rashtra; 17°17'13.78"N, 73°17'13.87"E; 18 Apr 1994; USNM 1128572 - one specimen; same data as for pre- ceding; USNM 1128570. Comparative material examined. Marphysa furcellata Crossland, 1903 ZANZIBAR - two specimens; 1901; between tide- marks, 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. zse.pensoft.net Description. Syntype NHM type 1092 incomplete, grav- id female, with 210 chaetigers, L10 = 9.3 mm, W10 = 5 mm TL = 860 mm (Fig. SA—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. 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 chae- tiger; median antennae reaching fourth chaetiger. Palpo- phores and ceratophores ring-shaped, short, thick; pal- postyles 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, sep- aration 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+] (Fig. 5H). MI three times longer than length of max- illary 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 tri- angular teeth; MII 3.2 times longer than cavity opening (Fig. 5H); ligament between left MNI—MITI 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. 51). Left MIV with two teeth larger than rest of teeth; attachment lamel- la semicircle, wide, better developed in right portion, sit- uated 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 por- tion, 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 fila- ments; with two forms: palmate with short button-shaped branchial stem in anterior chaetigers (Fig. 6F, H), pecti- nate in median chaetigers (Fig. 6G). In second syntype, branchiae ending 25 chaetigers before pygidium. One fil- ament 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. First pair of parapodia small; best developed in chae- tigers 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, fol- lowing gradually decreasing in size (Fig. 6A—K). Prechae- tal lobes short, in anterior chaetigers dorsal edge longer than ventral, in median-posterior chaetigers, as transverse Zoosyst. Evol. 97 (1) 2021, 121-139 129 al-MIV-L 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 | (NHMW type 1092); D-G. from Marphysa simplex Crossland, 1903 syntype 1 (BNHM 1955.4.1.21-25). al-MHI: at- tachment 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; MI-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). zse.pensoft.net 130 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex Figure 6. Marphysa teretiuscula (Schmarda, 1861a). A, B. Chaetiger 3; C. Chaetiger 7; D. Chaetiger 12; E. Chaetiger 14; F. Chae- tiger 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). fold (Fig. 6A—K). Chaetal lobes rounded in first 35 chaeti- other lobes, with aciculae emerging in mid-line (Fig. 6A— gers, shorter than other lobes, with aciculae emerging dor- _K). Postchaetal lobes well developed in first 56 chaeti- sal to mid-line; triangular from chaetiger 36, longer than gers; ovoid with dorsal edge longer than ventral edge in zse.pensoft.net Zoosyst. Evol. 97 (1) 2021, 121-139 following chaetigers; progressively smaller from chaetiger 19; from chaetiger 57, inconspicuous (Fig. 6A—K). Ven- tral 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 ven- tral 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 chae- tiger 140, with two. In second syntype, last 20 chaetigers with one acicula. Limbate chaetae of two lengths in same chaetiger, dor- salmost chaetae longer; reduced in number around chae- tiger 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 medi- an-posterior chaetigers, 3—4 thick, isodont wide chaetae, with up to 16—18 long and wide teeth (Fig. 7C). In posteri- or 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 chae- tigers (Fig. 7H), bidentate in median chaetigers, basally reddish translucent distally; with blunt teeth, distal and proximal teeth of similar sizes, booth teeth directed up- wards (Fig. 71). 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, MII 5—8, MIV 4—5+7-9. MI is 3-3.1 x longer than max- illary carriers; MI is 4.4—5.5x 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 cirr! 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 (R? = 0.7328, Pp = 1.65708E-05, n= 7, Fig. 8A), the last chaetiger with 1Sek developed postchaetal lobe (R? = 0.7976, p = 0.00028646, n = 7, Fig. 8B) and the first chaetiger with subacicular hook (R? = 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 fil- aments in the body could not be performed. 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-Guer- rero 2019). The syntypes label only states ‘“Trincomalie’ (Trincomalee) as the collecting site, but no collecting date is given. However, the expedition notes (Schmar- da 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. sim- plex and M. furcellata from Zanzibar. These species were differentiated, based on the shape of the prostomi- um and the pectinate chaetae. However, some authors considered these features irrelevant over time and pro- posed several synonyms between them or other spe- cies 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 MZ. sanguinea differed from M. furcellata by having bidentate subacicular hooks, whereas, in the latter species, they are unidentate. However, Day re- garded M. furcellata as a junior synonym of M. simplex (Crossland). Later, Day (1962) pointed out that M. fur- cellata 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 VM. macintoshi from M. furcellata and M. simplex (Crossland). Simultaneous- ly, 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. tereti- uscula (see Figs 5-7). Marphysa teretiuscularesembles 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. madra- si Hutchings, Lavesque, Priscilla, Daffe, Malathi & Glas- by, 2020 from Ennore Creek, India by having compound spinigers and inhabiting the same geographical area. zse.pensoft.net 132 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex 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. feretiuscula (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 um (A—D, G); 60 um (E); 50 um (F, H, I). zse.pensoft.net Zoosyst. Evol. 97 (1) 2021, 121-139 ow i=) ne) oa i) o R? = 0.7328 p= 1.65708E-05. First chaetiger with branchiae = oO f°?) oO oi (=) w Oo No oO R? = 0.7976 p = 0.00028646 = oO Last chaet. with postch. lobe f 0 2 4 6 8 10 > WW First chaet. with sub. hook 133 ff oO w oO wo oOo Nh on N oO R? = 0.6291 p = 2.02774E-07 = a 0 2 4 6 8 10 Average between L10 and W10 (mm) 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 (R? = 0.7328, p = 1.65708E-05, n = 7); B. Last chaeti- ger where the postchaetal lobe is developed (R? = 0.7976, p = 0.00028646, n = 7); C. Chaetiger where the subacicular hook starts (R? = 0.6291, p = 2.02774E-07, n= 7). However, M. teretiuscula bears only subacicular chaetae compound spinigers, while M. borradailei, M. gravelyi and M. madrasi have both subacicular spinigers and lim- bate 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. teretiuscu- la, M. furcellata and M. macintoshi differ by distributing the branchial filaments throughout the body. In M. tereti- uscula, the maximum number of five branchial filaments is present only in a small/low number of chaetigers (be- tween 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). Marphysa_ teretiuscula resembles M. americana Monro, 1933, M. angelensis Fauchald, 1970, M. depressa (Schmarda, 1861la), 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 . 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, MM. 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. zse.pensoft.net 134 oOo = aoa => oO to) oOo 100 150 200 250 Number of branchial filaments oO 100 120 Acevedo, |.C., Idris, |.: Solving the taxonomic status of Marphysa simplex A 50 100 150 200 250 300 350 Number of chaetigers 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. Discussion Marphysa group without compound chaetae At present, the small Marphysa group A proposed by Fau- chald (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 ear- ly stages, a common condition in other Marphysa species (Southern 1921; Atyar 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 ad- dition, Zanol et al. (2014) supported this synonymy in a phylogenetic analysis of Eunicidae, based on morpholog- ical and molecular evidence, confirming this uncommon condition is developed in some Marphysa species. zse.pensoft.net The emergence of compound chaetae in the early stag- es has been well documented in some Marphysa species from India: Marphysa borradailei (Borradaile 1902; Pil- lai 1958), M. gravelyi (Malathi et al. 2011) and Marphy- sa 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 con- vex and straight edges as they emerge (Borradaile 1902: Southern 1921; Aiyar 1931; Pillai 1958) just after the ap- pearance of two unjointed (simple) chaetae (Borradaile 1902; Atyar 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 1s developed, only the same compound chaeta emerges in chaetigers 2 and 3 (Borradaile 1902; South- ern 1921; Atyar 1931; Pillai 1958). At the time of de- velopment of chaetigers 12—13, two types of compound chaetae can be observed (Atyar 1931; Pillai 1958): (1) a hooked chaeta, herein judged as the compound falciger; and (2) a sickle-shaped chaeta, also called falcigerous by Atyar (1931) and Pillai (1958), herein interpreted as the typical compound spiniger. Atyar (1931) also described the shift and loss of chaetae in larger specimens of Marphysa sp. 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