Nemertesia tropica spec. nov. from Indonesian waters near Bali. Description of the new species and a review of the genus Nemertesia Lamouroux, 1812 (Leptothecata, Hydrozoa, Cnidaria) F. Ramil & W. Vervoort Ramil, F. & W. Vervoort. Nemertesia tropica spec. nov. from Indonesian waters near Bali. Description of the new species and a review of the genus Nemertesia Lamouroux, 1812 (Leptothecata, Hydrozoa, Cnidaria). Zool. Med. Leiden 80-1 (9), 10.iii.2006: 113-158, fi gs 1-3.— ISSN 0024-0672. Francisco Ramil, Departamento de Ecoloxía e Bioloxía Animal, Facultade de Ciencias do Mar, Universi- dade de Vigo, Campus Lagoas-Marcosende, 36200 Vigo, Spain (e-mail [email protected]). Willem Vervoort, National Museum of Natural History, P.O. Box 9517, 2300 RA, Leiden, The Netherlands (e-mail: [email protected]). Key words: Cnidaria; Hydrozoa; Leptolida; Leptothecata; Plumulariidae; Nemertesia; Indonesian waters. A new species of the leptolid family Plumulariidae, Nemertesia tropica spec. nov. is described. The various species of Nemertesia are listed and their synonymy and characters discussed. Allocation in Nemertesia of some species previously described in Plumularia by Fraser (1938-1948) necessitated the introduction of two new names, viz. Nemertesia californica nom. nov. for Plumularia mutabilis Fraser, 1948 and Nemertesia mexicana nom. nov. for Plumularia reversa Fraser, 1938. Introduction During routine identifi cation of leptolid samples collected in Indonesian waters by scientists of the National Museum of Natural History, Leiden, the Netherlands, taking part in expeditions exploring coral reefs in various Indonesian habitats, a species of the leptolid genus Nemertesia Lamouroux, 1812 with an unusual combination of characters was discovered. Though the specimens were sterile they were found in such abundance and had such a striking appearance that it seemed advisable to draw attention to this new reef inhabitant by publishing its description. In the process of identifi cation, descriptions of species hitherto referred to Nemer- tesia were checked and the limitation of this genus and the closely related genus Plu- mularia Lamarck, 1816, were considered. It proved to be a pleasant coincidence that one of the authors (WV) had been involved in a re-investigation of the Allan Hancock hydroid collection, now preserved in the Santa Barbara Museum of Natural History, Santa Barbara, California, USA, a collection previously identifi ed by C. McLean Fraser (1938a, 1938b, 1938c, 1939, 1947, 1948). Though the results of the re-inspection of the Allan Hancock collection, carried out in cooperation with Dr Dale R. Calder, Royal Ontario Museum, Toronto, Canada, will be published elsewhere, some of the pre- liminary results have been incorporated here, as these bear directly on the results of the present research and the limitation and species composition of Nemertesia and Plumularia. 114 Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) a b Fig. 1. Nemertesia tropica spec. nov., NNM-LIPI-WWF Expedition, Stn BAL. 07. a, holotype; b, detail of stems and arrangement of hydrocladia. Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) 115 Systematic Account Nemertesia tropica spec. nov. (fi gs 1-3) Material.— NNM-LIPI-WWF Expedition, Stn BAL.07, Indonesia, Bali, Sanur, Penjor Point, 08°42’04”S 115°16’18”E, slowly declining reef slope, sandy base; scuba diving to 16 m depth; 02.04.2001; collected by L.P. van Ofwegen & M. Slierings. Two colonies, the fi rst composed of c. 50 unbranched stems fused basally to form several bundles, fi rmly anchored in sediment by means of strong stolonal fi bers, maxi- mal height 160 mm; no gonothecae (holotype, RMNH-Coel. 32358); the second composed of c. 20 un- branched stems, 25-170 mm high and basally fused (paratype, RMNH-Coel. 33333). Description.— Colonies with the appearance of a fl attened brush, composed of un- branched stems to 170 mm high of a dark brown, almost black colour, basally fused to form several bundles of 20-30 stems that are united by a globular mass of stolonal fi b- ers, anchoring the colonies in sediment of the bottom. Proximal parts of colonies en- crusted by bryozoans and ascidians. Hydrocladia transparent. Stem unbranched, monosiphonic, non-canaliculated, with straight nodes at irregu- lar distances; the resulting internodes of greatly varying lengths, with thick, dark brown to blackish perisarc and strong apophyses supporting hydrocladia of 2.0-2.5 mm length. Apophyses arranged in an irregular spiral along length of stem, 5 to 7 apo- physes along one turn of the spiral; number of apophyses per internode greatly varied, the internode may be occupied by one or several turns of the spiral. No nematothecae occur on internodes. Apophyses strong, slightly curved upwards, with a well devel- oped mamelon and two pairs of movable, bithalamic nematothecae, one below, one above mamelon. Perisarc of apophyses strong. Hydrocladia fl exuous, curved upwards, monomerously segmented; nodes distinct and oblique; fi rst internode short, without nematothecae or hydrotheca; following in- ternodes slender; hydrotheca placed halfway length of internode; one mesial inferior nematotheca and a pair of lateral nematothecae. Hydrotheca small, cup-shaped, ab- cauline wall straight, in line with wall of internode on which it rests. Rim of hydrotheca circular, in lateral view rounded, slightly depressed adcaudally. Nematothecae all bitha- lamic, with distinct ring-shaped septum separating both chambers and distinctly con- tracted at that level; upper chamber with Table I. Measurements of Nemertesia tropica spec. slightly scooped rim. All nematothecae nov. in μm: have the same conical appearance; those on the apophyses being slightly larger, Colony, height of stems ( in mm) 25 - 170 the mesial nematotheca slightly curved Stem, diameter 370 - 420 while the lateral nematothecae, inserting First hydrocladial internode, length 40 - 80 near the hydrothecal rim, are straight. Diameter at node 60 - 100 Perisarc of internodes generally thin, Hydrocladial internode, length 250 - 350 Diameter at node 40 - 75 with ring-shaped internal thickenings Hydrotheca, length abcauline wall 60 - 80 below insertion of mesial nematotheca, Diameter at rim 70 - 90 on abcauline wall of internode at level of Mesial nematotheca, length 60 - 80 rim of that nematotheca and at the ab- Diameter at rim 30 - 40 cauline wall just under the node. Lateral nematotheca, length 60 - 80 Gonothecae absent. Diameter at rim 35 - 40 116 Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) Fig. 2. Nemertesia tropica spec. nov., NNM-LIPI-WWF Expedition, Stn BAL. 07. a, stem apophysis and proximal part of hydrocladium in lateral view; b, hydrothecate internode in frontal view. Scale 200 μm. The new species resembles Nemertesia antennina (Linnaeus, 1758) in the general structure of the colony (unbranched, monosiphonic, basally adnate stems that in con- tradistinction to N. antennina are non-canaliculated). The arrangement of the apophyses in an irregular spiral along the stems differs from the decussate arrangement in whorls of 3-5 apophyses found in N. antennina. The hydrocladia in N. tropica spec. nov. are monomerous; all internodes, with the exception of the fi rst, have a hydrotheca halfway its length, a mesial inferior nematotheca and a pair of nematothecae at the hydrothecal rim. In N. antennina hydrothecate internodes of similar structure alternate with ahydro- thecate internodes with a single nematotheca. Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) 117 Fig. 3. Nemertesia tropica spec. nov., NNM-LIPI-WWF Expedition, Stn BAL. 07, stem apophysis and insertion of hydrocladium in lateral view. Scale 200 μm. The species name ‘tropica’ is a reference to the tropical seas of Indonesia where the species was found. Review of the genus Nemertesia Lamouroux, 1812 The discovery of this supposed new species made it necessary to review the species of Nemertesia and to consider the features of this plumulariid genus. The inspection of the Allan Hancock leptolid material, now preserved in the Santa Barbara Museum of Natural History, Santa Barbara, California, U.S.A., by Dr Dale Calder, Royal Ontario Museum, Toronto, Canada and the second author, considerably extended the number of species and made it necessary to redefi ne the characters of the genus. For Nemertesia Lamouroux, 1812 we now present the following description: Colonial leptolids composed of erect stem or stems rising from compact bundle of intertwining hydrorhizal tubes usually anchoring the colony in sediment or attaching it to fi rm substrate. Hydrorhizal tubes occasionally with nematothecae. Stem with strong perisarc, without branches or branched, in which case branches may leave the stem under a sharp angle or curve upwards to run almost parallel to main stem. Stem monosiphonic or polysiphonic by the presence of secondary tubes adhering to and running parallel with the main stem; secondary tubes continued along the branches, in some instances forming the side branches. Stem either with a single canal in the 118 Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) coenosarc (non-canaliculated) or with a number of coenosarcal canals (canaliculated), divided into internodes by ring-shaped constrictions of the perisarc (nodes), usually perpendicular to length axis of stem, occasionally absent or visible on part of stem. Stem internodes or stem provided with upwardly curved projections supporting hy- drocladia (apophyses). Number of apophyses and their arrangement varied; they may be arranged in two opposed longitudinal rows in one plane, in four longitudinal rows in two planes that intersect perpendicularly or in more longitudinal rows (up to 12). Usually their arrangement is in whorls, but may also be quite irregular. Number of longitudinal rows may be twice the number of apophyses per whorl by decussate arrangement of apophyses in two succeeding whorls (apophyses of next whorl fall in space left open by previous whorl). Arrangement of apophyses in young colonies (or younger parts of a colony) often in two rows in one plane, with apophyses either op- posite or alternating (resembling condition found in genus Plumularia), but ultimately always leading towards arrangement in a larger number of longitudinal rows, in cer- tain species resulting in very regular arrangement, in others in irregular arrangement of apophyses along the stem. Stem or stem internodes with bithalamic, movable, fun- nel-shaped nematothecae; apophyses in addition to nematothecae also with elevated “pore” or sarcostyle, named mamelon; development of mamelon varied in various species. Hydrocladia of moderate length (c. 5-15 mm), composed of a number of internodes separated by oblique or straight nodes, occasionally in alternate arrangement. Inter- nodes either all hydrothecate (monomerous condition) or alternately hydrothecate and ahydrothecate (heteromerous condition). Hydrothecate internodes have one hydrothe- ca in adcauline position (facing the stem), a pair of nematothecae inserted approxi- mately at the hydrothecal rim (fl anking nematothecae), and a number of median nema- tothecae, usually one or two below hydrotheca (inferior or infracalycine) and one or two above hydrotheca (superior or supracalycine). Ahydrothecate internodes are either devoid of nematothecae or have one or two median nematothecae. The number of nematothecae (and under certain conditions number of hydrothecae) may be increased by fusion of internodes or as the result of regeneration after damage. First internode of a hydrocladium may be ahydrothecate or hydrothecate. Hydrothecae cup-shaped or tumbler-shaped, with smooth, circular rim, exclusively found on the hydrothecate in- ternodes. All nematothecae are movable, bithalamic and funnel-shaped; adcauline nematothecal rim of superior chamber may be scooped. Flanking nematothecae may be increased in length. Gonothecae elongated ovoid, narrowing basally into a short pedicel; gonothecae inserted at apophyses, either singly or in pairs, occasionally fl attened, lobed. Not fully mature gonothecae with rounded apex; mature gonothecae frequently with latero-ter- minal, more or less circular aperture, directed adcaudally. Gonothecae with attenuated apex have also been described. Some species apparently have sexual dimorphism of gonothecae; female gonothecae with circular, latero-terminal aperture, male gonothecae with attenuated apex with small, terminal aperture. Gonothecae in majority of species listed below unknown. Presence of nematothecae on the gonotheca has been described in only two species: Nemertesia indivisa (Allman, 1883) and Nemertesia cylindrica (Kirchen- pauer, 1876). Gonophore sessile, styloid (fi xed sporosacs). Type (by monotypy): Sertularia antennina Linnaeus, 1758. Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) 119 The genus Nemertesia, as diagnosed here, encompasses the following taxa: Antennularia Lamarck, 1816, fi rst named species Antennularia indivisa Lamarck, 1816; Antennopsis Allman, 1877, type, by monotypy Antennopsis hippuris Allman, 1877; Sciurella Allman, 1883, type, by monotypy Sciurella indivisa Allman, 1883; Nemertella Stechow, 1923, type, by original designation (Stechow, 1923b: 116) Nemer- tesia (Antennularia) hexasticha Kirchenpauer, 1876. Left out of consideration are the genera Nigellastrum Oken, 1815, Cymodocea Lam- ouroux, 1816, Lowenia Meneghini, 1843, and Heteropyxis Heller, 1868. Nigellastrum Oken, 1815, contains a variety of widely different leptolid species. Oken’s 1815 Lehrbuch der Naturgeschichte has been banned for the purpose of Zoological Nomenclature (with the exception of the genus Halecium, see I.C.Z.N., 1982) by a decision of the International Commission on Zoological Nomenclature (see Melville & Smith, 1987); the genus Nigel- lastrum had been re-introduced by Stechow (cf. Stechow, 1923c: 160). Cymodocea Lam- ouroux, 1816 contains two unidentifi able species. Lowenia Meneghini, 1843, originally encompassed three species: Sertularia setacea Linnaeus, 1758; Sertularia pinnata Linnaeus, 1758 and Lowenia tetrasticha, a nomen nudum, validated later on by a description (Meneghini, 1845). Stechow (1923c: 228) designated Lowenia tetrasticha as the type of Lowenia Meneghini, 1843; Calder (1997: 14) showed this designation to be invalid and subsequently designated Sertularia setacea as the type species of Lowenia, which makes Lowenia Meneghini 1843 a junior synonym of Plumularia Lamarck, 1816. Heteropyxis Heller, 1868, is a replacement name for Lowenia Meneghini, 1843. Inspection of the list of species and the table revealing their principal characters will obviously demonstrate the lack of information on reproductive structures and principal morphological characters in many of its representatives. It seems inappropriate there- fore, to speculate on the monophyletic character of Nemertesia. Although the large number of species and the heterogeneity of their external appearance suggest polyphy- ly they are uniform in arrangement and structure of the hydrocladia that offer the prin- cipal differences with the closely allied genus Plumularia Lamarck, 1816, a genus even more speciose than Nemertesia. The principal difference with Plumularia is the colony structure: the hydrocladia are pinnately arranged in one plane (but occasionally merg- ing into a spiral arrangement). Structure and development of the reproductive struc- tures in Plumularia suggests that the genus is polyphyletic; it also contains many species with unknown gonosome. List of the species of Nemertesia Lamouroux, 1812 Nemertesia alternata (Fraser, 1938) Antennularia alternata Fraser, 1938a: 58-59, pl. 13 fi g. 66. Insuffi ciently characterized species which should be redescribed from the type ma- terial. Nemertesia americana (Nutting, 1900) Antennularia americana Nutting, 1900: 69-70, pl. 9 fi gs 3, 4. 120 Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) Bedot (1917) considered this species to be a variety of Nemertesia antennina (L., 1758) [viz. Nemertesia antennina var. irregularis (Quelch, 1885)], here sunk into the synonymy of N. antennina. Pending the inspection of North-west Atlantic material of this species it is tentatively given specifi c rank. Nemertesia anonyma Ansín Agís, Ramil & Vervoort, 2001 Nemertesia anonyma Ansín Agís, Ramil & Vervoort, 2001: 226-228, fi g. 86. Nemertesia antennina (Linnaeus, 1758) Sertularia antennina Linnaeus, 1758: 811. Cymodocea ramosa Lamouroux, 1816: 212, pl. 7 fi gs 1a, A. Nemertesia (Antennularia) antennina var. minor Kirchenpauer, 1876: 51, pl. 2 fi g. 23a. Antennularia irregularis Quelch, 1885: 8, pl. 2 fi gs 4, 4a, 4b. Antennularia octoseriata Jäderholm, 1896: 15, pl. 2 fi g. 6. Antennularia pinnata Nutting, 1900: 71-72, pl. 5 fi gs 5, 6. Antennularia antennina var. longa Billard, 1904: 216. Antennularia Perrieri var. antennoides Billard, 1904: 217. Antennularia antennina var. minor Stechow, 1909: 82. Nemertesia antennina; Ansín Agís, Ramil & Vervoort, 2001: 193-200, fi gs 76, 77 (full synonymy and discussion). Nemertesia belini Bedot, 1916 Nemertesia belini Bedot, 1916: 1; Ansín Agís, Ramil & Vervoort, 2001: 200-204, fi gs 78, 79 (discussion). Nemertesia californica nom. nov. Plumularia mutabilis Fraser, 1948: 285, pl. 41 fi g. 50. Inspection of Fraser’s material of Plumularia mutabilis proves this species to be a distinct Nemertesia, in which genus the species name ‘mutabilis’ is preoccupied by Anten- nularia mutabilis Fraser, 1948. The material, though sterile, is in good condition and fi t for redescription. Nemertesia ciliata Bale 1914 Nemertesia ciliata Bale, 1914b: 170, pl. 36 fi g. 1; Vervoort & Watson, 2003: 376-378, fi g. 91F-H (description and references). Nemertesia ciliata var. cruciata Bale, 1915: 300-301. Nemertesia polygeniculata Rho & Park, 1984: 256-260, fi gs 2, 3. Nemertesia compacta (Fraser, 1938) Antennularia compacta Fraser, 1938b: 111, 115, pl. 17 fi g. 6. Insuffi ciently characterized species based on juvenile, sterile material. Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) 121 Nemertesia constricta (Fraser, 1948) Antennularia constricta Fraser, 1948: 263, pl. 33 fi g. 31. Insuffi ciently characterized species based on juvenile, sterile material. Nemertesia cylindrica (Kirchenpauer, 1876) Plumularia cylindrica Kirchenpauer, 1876: 45, pl. 1 fi g. 1, pl. 4 fi gs 1, 1a, 1b. Antennularia cylindrica Bale, 1884: 146, pl. 10 fi g. 7. Nemertesia cylindrica; Watson, 2000: 49-51, fi g. 38A-E (description and synonymy). With Nemertesia indivisa (Allman, 1883) also brought in the genus Sciurella Allman, 1883, here considered synonymous with Nemertesia. Nemertesia cymodocea (Busk, 1851) Antennularia cymodocea Busk, 1851: 119. Nemertesia cymodocea; Vervoort & Watson, 2003: 379-380, fi g. 91I, J (synonymy and description). Nemertesia (Antennularia) decussata Kirchenpauer, 1876: 52, pl. 2 fi g. 24, pl. 3 fi g. 24, pl. 7 fi g. 24. Antennularia hartlaubi Ritchie, 1907: 542, pl. 3 fi g. 4a, b. Nemertesia dissimilis (Fraser, 1943) Antennularia dissimilis Fraser, 1943: 83, 94, pl. 19 fi g. 15; 1944: 324, pl. 68 fi g. 310 (description). Nemertesia distans (Nutting, 1900) Antennopsis distans Nutting, 1900: 73-74, pl. 12 fi gs 1, 2. Nemertesia disticha (Heller, 1868) Heteropyxis disticha Heller, 1868: 44, pl. 2 fi gs 9, 10. Considered by Stechow (1919) to be a species of Nemertesia; referred to Plumularia by Bedot (1921b: 27, 34). Nemertesia duseni (Jäderholm, 1904) Plumularia duseni Jäderholm, 1904: 5-6, pl. 1 fi g. 4, pl. 2 fi gs 2, 3; Bedot, 1917: 43-44 (diagnosis). Nemertesia elongata Totton, 1930 Nemertesia elongata Totton, 1930: 229, fi g. 64; Vervoort & Watson, 2003: 381-384, fi g. 93A-C (references and description). Nemertesia falcicula (Ramil & Vervoort, 1992) Plumularia falcicula Ramil & Vervoort, 1992: 180-183, fi g. 46a-h; Ansín Agís, Ramil & Vervoort, 2001: 205- 207, fi g. 80 (references and description). 122 Ramil & Vervoort. Nemertesia tropica spec. nov. from Indonesia. Zool. Med. Leiden 80 (2006) Nemertesia fascicularis (Allman, 1883) Antennularia fascicularis Allman, 1883: 24-25, pl. 4 fi gs 5, 6; Billard, 1908: 759. Corhiza fascicularis; Millard, 1968: 276; Schuchert, 1997: 140. This species was doubtfully referred to the genus Antennopsis by Bedot (1921b). Mil- lard (1968: 276) and Schuchert (1997: 140) refer the species to the genus Corhiza Millard, 1962 and we concur. Nemertesia fraseri Ramil & Vervoort, 1992 Antennularia irregularis Fraser, 1938a: 59, pl. 13 fi g. 67; 1939: 161; 1948: 266. Nemertesia fraseri Ramil & Vervoort, 1992: 172-173. Based on sterile material, needs to be redescribed as it is so far based on inadequate characters. Nemertesia geniculata (Nutting, 1900) Antennularia geniculata Nutting, 1900: 71, pl. 10 fi gs 3, 4; Fraser, 1944: 325, pl. 68 fi g. 311. The only description of this species is that by Nutting (1900), copied by Fraser (1944); characters listed in table are those taken from descriptions. Apparently only spe- cies with paired gonothecae. Nemertesia gracilis (Fraser, 1948) Antennularia gracilis Fraser, 1948: 264, pl. 33 fi g. 32. The holotype of this species is a regenerating, 35 mm high stem and so far insuffi - ciently characterized. The available type series is probably unfi t for a proper redescrip- tion. Nemertesia hexasticha Kirchenpauer, 1876 Nemertesia (Antennularia) hexasticha Kirchenpauer, 1876: 52, 54, pl. 2 fi g. 25, pl. 3 fi g. 25, pl. 8 fi gs 25, 25a, 25b. Nemertella hexasticha; Stechow, 1923c: 231. Not redescribed since Kirchenpauer’s original account. Placed in the genus Nemertel- la Stechow, 1923 because of the (occasional) occurrence of secondary hydrocladia. Nemertesia hippuris (Allman, 1877) Antennopsis hippuris Allman, 1877: 35, pl. 21 fi gs 3, 6. Type species of Antennopsis Allman, 1877, here considered coterminous with Nemer- tesia Lamouroux, 1812.