Sea anemones (Cnidaria, Actiniaria) of Singapore: redescription and taxonomy of Phymanthuspinnulatus Martens in Klunzinger, 1877 Author Yap, Nicholas Wei Liang Author Tan, Ria Author Yong, Clara Lei Xin Author Tan, Koh Siang Author Huang, Danwei text ZooKeys 2019 840 1 20 http://dx.doi.org/10.3897/zookeys.840.31390 journal article http://dx.doi.org/10.3897/zookeys.840.31390 1313-2970-840-1 0E7E96911F874C47B482F4E15052A987 Phymanthus pinnulatus Martens in Klunzinger, 1877 Figs 2, 3, 4, 5, 6, 7 Phymanthus pinnulatum Martens in Klunzinger, 1877: 87 (original description). Phymanthus pinnulatum : Haddon 1898 : 496; Carlgren 1949 : 75. Phymanthus pinnulatus : Fautin 2016 : 346. Occurrence and materials collected in Singapore (Fig. 1). (* - observed alive; bold - morphotypes with smooth marginal tentacles or reduced protuberances): Berlayer Creek (ZRC.CNI.1343 x4*), Big Sister's Island (ZRC.CNI.0982 x1; ZRC.CNI.1103 x1*; ZRC.CNI.1163 x1*; ZRC.CNI.1045 x1*; ZRC.CNI.1347 x4*), Changi East Beaches (ZRC.CNI.1084 x1*; ZRC.CNI.1106 x1*), Chek Jawa (photographed but not collected), Cyrene Reef (ZRC.CNI.1089 x1*; ZRC.CNI.1112 x2*; ZRC.CNI.1145 x1*; ZRC.CNI.1342 x4*), East Coast Park Beaches (ZRC.CNI.1039 x1*; ZRC.CNI.1046 x1*; ZRC.CNI.1110 x1*), Kusu Island (ZRC.CNI.1162 x1*), Pulau Hantu (ZRC.CNI.0015 x1; BMNH1995.1006 x1; CASIZ161242 x1), Pulau Jong (BMNH1996.355 x1), Pulau Sekudu (ZRC.CNI.0738 x1), Pulau Semakau (ZRC.CNI.1031 x1*; ZRC.CNI.0318 x1; ZRC.CNI.0321 x1; ZRC.CNI.0322 x1; ZRC.CNI.0639 x1; ZRC.CNI.1098 x1*; ZRC.CNI.1361 x1*), Pulau Tekukor (ZRC.CNI.0993 x3*, of these only one has reduced protuberances; BMNH1996.313 x1; ZRC.CNI.1306 x1*), Sentosa (Tanjong Rimau) (ZRC.CNI.1345 x4*), St John's Island (ZRC.CNI.0467 x1), Tanah Merah (photographed but not collected), Terumbu Bemban (ZRC.CNI.1223 x1*), Terumbu Pempang Tengah (ZRC.CNI.1028 x1*; ZRC.CNI.1029 x1*), Terumbu Raya (ZRC.CNI.1111 x1*), Terumbu Semakau (ZRC.CNI.0493 x1). Figure 1. Map of Singapore where specimens of Phymanthus pinnulatus were collected for this study: 1, Berlayer Creek ( 1°15'56"N ; 103°48'25"E ); 2, Big Sisters' Island (Pulau Subar Laut) ( 1°12'50"N ; 103°50'05"E ); 3, Changi East Beaches ( 1°18'45"N ; 104°00'31"E ); 4, Chek Jawa ( 1°24'25"N ; 103°59'23"E ); 5, Cyrene Reef (Terumbu Pandan) ( 1°15'28"N ; 103°45'19"E ); 6, East Coast Park Beaches ( 1°17'36"N ; 103°53'46"E ); 7, Kusu Island (Pulau Tembakul) ( 1°13'25"N ; 103°51'39"E ); 8, Pulau Hantu ( 1°13'35"N ; 103°45'03"E ); 9, Pulau Jong ( 1°12'54"N ; 103°47'12"E ); 10, Pulau Sekudu ( 1°24'19"N ; 103°59'17"E ); 11, Pulau Semakau ( 1°11'58"N ; 103°45'31"E ); 12, Pulau Tekukor ( 1°13'51"N ; 103°50'18"E ); 13, Sentosa (Tanjong Rimau) ( 1°14'47"N ; 103°49'56"E ); 14, St John's Island ( 1°13'17"N ; 103°50'55"E ); 15, Tanah Merah ( 1°18'45"N ; 103°59'34"E ); 16, Terumbu Bemban ( 1°12'36"N ; 103°44'27"E ); 17, Terumbu Pempang Tengah ( 1°13'33"N ; 103°43'50"E ); 18, Terumbu Raya ( 1°12'46"N ; 103°45'09"E ); 19, Terumbu Semakau ( 1°12'46"N ; 103°46'07"E ). Type material examined. Holotype, ZNB Cni 1324, collected by E. von Martens. A single specimen, 60 mm in length, flaccid, cut longitudinally, a slice of the distalmost margin and part of the proximal end missing, though a little of the pedal disc remains, cream-coloured entirely (Fig. 2A); NRS76 consists of three pieces originating from ZMB Cni 1324 (see Fautin 2016 ), all pieces cream-coloured in preservative: a piece of the distalmost end with oral disc and marginal tentacles present, 11 mm in length; a piece of mesentery, fertile, 9 mm wide; a 30 mm longitudinal strip of the column (Fig. 2B). Figure 2. Holotype of Phymanthus pinnulatum Martens in Klunzinger, 1877 A entire specimen present at the Museum fuer Naturkunde, Berlin (ZMB Cni 1324), Germany B three pieces of the holotype removed from the Berlin specimen now at Naturhistoriska Riksmuseet (NRS76), Stockholm, Sweden. Abbreviations: m, mesenteries. mt, marginal tentacles. mf, mesenterial filaments. mp, marginal projection. o, oral disc. pd, pedal disc. Photographs by NWL Yap. Natural history. Usually encountered during low tide, with upper portion exposed, oral disc and marginal tentacles expanded (Fig. 3A, B, C). Sediment and small shell fragments may adhere to verrucae (Fig. 3D). Lower body usually deep in crevices or buried in sand or coral rubble. Pedal disc attached to buried rock, fragments of shell or coral rubble. Retracts quickly and deeply into substratum when disturbed, pulling in marginal tentacles completely. Animal typically found singly, with multiple individuals separated by a short distance (> 20 cm), although clusters up to four have been observed. Zooxanthellate. Figure 3. Living specimens of Phymanthus pinnulatus , external morphology of oral end A expanded individual of green "banded" colour morph, in situ. Photograph by R Tan B an expanded slaty-green "plain" coloured individual, with extensive branching of its protuberances, in situ. Photograph by R Tan C a third colour morph with brilliant electric blue marginal tentacles, in situ. Photograph by NWL Yap D a partially contracted individual in situ, with its oral end protruding from the substratum; note longitudinal rows of verrucae along intermesenterial spaces, extending proximally from the oral end towards mid column, in situ. Photograph by R Tan. Marginal tentacles. 96 in total; one individual with 98 (ZRC.CNI.1342). All of similar length, equal to oral disc radius or longer (Figs 3A, B). Arranged hexamerously in four cycles but octamerously in one individual (ZRC.CNI.1029). Cycle closest to margin exocoelic; innermost cycles endocoelic. One per endo-/exocoel. Ramified protuberances occur laterally along both sides, symmetrical, alternating between large and small knobs (Fig. 4A). In life, branching appears extensive; when preserved, appears as low knobs (Figs 4A, B, respectively). Extent of branching may vary; some individuals have protuberances as slight bumps while in others the entire length is smooth (Figs 4C, D). Tip narrow and blunt, without perforation (Fig. 4E); base wide. Colour variable, from greenish-brown, slatey-grey to blue with golden tinge (Figs 3A, B, C); tip with green, purple, or pink cast. In fixed individuals, tentacles cream-coloured to greenish, translucent. Protuberances cream-coloured to gold on oral side; usually with a white line adjoining opposite protuberances (Fig. 4A). Figure 4. Marginal tentacle and marginal projection appearance of Phymanthus pinnulatus A close-up of ramified protuberances of a living specimen. Photograph by NWL Yap B close-up of protuberances from a fixed specimen (ZRC.CNI.1345); note that finer details of protuberance branching are lost in preserved/fixed specimens, branching of protuberances now appear as knobs. Photograph by NWL Yap C a morphotype of that lacks ramified protuberances. Note that this individual (ZRC.CNI.1029) is atypical as it has lesser marginal tentacles, by which are also octo-ramously arranged. Photograph by NWL Yap. D a "smooth" tentacle morphotype, in situ. Photograph by R Tan E close-up of a marginal tentacle tip from a fixed specimen (ZRC.CNI.1342). Note absence of perforation at tip F close-up of a row of marginal projections of a fixed specimen (ZRC.CNI.1342). Note perforations (arrowed). Abbreviations: mt, marginal tentacles; mtt, marginal tentacle tip; p, protuberances. Photographs by NWL Yap. Column. Colour variable, from tan to translucent white. Distalmost end dark-brown. May appear whitish or cream-coloured in life, or with a light green tinge in preserved specimens. Distalmost end flared outwards when animal is expanded; mid-section uniform diameter; pedal end may spread outwards when animal is attached to a surface. Diameter of distalmost end greater than pedal disc. Marginal projections present along margin of distalmost end; may be inflated, perforated (Fig. 4F), with a central white dot. Dot not visible in preserved specimens. Longitudinal rows of adherent verrucae present, extending proximally to mid-section (Fig. 3D). In life, shell fragments or substratum particles may be attached to verrucae. Verrucae outline eye-shaped, as low white bumps, middle depressed, diameter <1 mm. Verrucae rows endocoelic; alternate long and short rows. Longer rows with typically more than eight verrucae; shorter rows with less than five. Mesenterial insertions seen as white lines that extend from distalmost to pedal end. Past mid-section: plain and smooth, without any obvious structures. Cinclides present, visible only when limbus is expanded. Fosse present, shallow, ca. 1 mm deep. Oral disc. Outline round, flat when fully expanded; diameter 40 mm or greater. Colour in life grey to dark brown, with white markings flanking outwards; in fixed specimens, cream-coloured to translucent white. Discal tentacles present, arranged in radial rows extending from mouth to marginal tentacles, both endo- and exocoelic, numerous in a row (Fig. 5A). Discal tentacles outline: slim oval, as low bumps (Fig. 5B), some with middle sunken in, dependent on state of expansion. Discal tentacles dark-brown or grey in life. In preserved individuals, these are very inconspicuous, seen as horizontally radiating short grey dashes (Fig. 5C), may be very faint, or not seen at all, depending on state and age of specimen (e.g. Figs 5C, D). Wall thin; dark lines corresponding to mesenterial insertions visible through wall, extends from the mouth to margin. Central mouth oval and flat, area around it may be translucent. Two siphonoglyphs, symmetrical. In life, these may be white with pinkish streaks. Preserved, siphonoglyphs appear cream-coloured. Figure 5. Detail of the oral discs of Phymanthus pinnulatus , external morphology A top view of discal tentacles present on a live individual, arranged as radial rows between intermesenterial spaces, extending from the mouth towards the region of the marginal tentacles (ZRC.CNI.1361) B side view of discal tentacles of a living specimen; note the low and reduced elevation of tentacles (ZRC.CNI.1046) C faint and reduced radial rows of discal tentacles (arrowed) present on a recent, formalin-fixed specimen (ZRC.CNI.1345) D very reduced and barely noticeable remnants of discal tentacles (arrowed) present on the holotype (NRS76); note that this specimen was preserved before 1877. Abbreviations: m, mesenteries; mt, marginal tentacles. Photographs by NWL Yap. Pedal disc. Oval, flat, same colour as proximal section of column. Thin-walled, mesenterial insertions appear as radiating white lines. Strongly adherent; readily attaches to surfaces to follow contour of substratum. Internal morphology. Actinopharynx longitudinally pleated, extends proximally until mid-column. Oral and marginal stomata present. Mesenteries contain zooxanthellae, arranged in three orders. All 12 pairs of highest order complete, fertile and with filaments; two of these directives, each attached to a siphonoglyph. Mesenteries of second order incomplete, but all fertile with filaments, 12 pairs. In one individual (ZRC.CNI.0467) nine pairs of imperfect mesenteries were present in the second order. Twenty-four pairs of mesenteries small, without filaments and retractor pennon make up third order. All mesenteries, except smallest, extend to the proximal end. Sphincter muscle absent (Fig. 6A). Retractor muscles: strong, diffuse to diffuse circumscript. Parietobasilar muscle extends away from mesentery, as a reduced pennon (Fig. 6B), poorly developed. No internal broods encountered. Figure 6. Internal musculature of Phymanthus pinnulatus A longitudinal section of ZRC.CNI.0321 at the margin, showing lack of marginal sphincter muscle. Fosse is indicated by a black star B cross-section of ZRC.CNI.0993. Note the presence of well-developed retractor muscles (white star), and oocytes. Abbreviations: a, actinopharynx; d, directives; mp, marginal projection; mt, marginal tentacle; pb, parietolbasilar muscle. Scale bar: 10 mm. Photographs by NWL Yap. Cnidom. Spirocysts, basitrichs, microbasic p-mastigophores (Table 1). Cnidae illustrated in Fig. 7. No cnidom data yielded from holotype (i.e., ZMB Cni 1324 and NRS 76), cnidae present damaged with crystalline appearance. Distribution. Singapore ( Klunzinger 1877 ; this study), Indonesia (pers. obs.; see discussion below) and Northern Australia (see discussion below). Figure 7. Cnidae of Phymanthus pinnulatus A spirocyst B basitrich C spirocyst D basitrich E spirocyst F basitrich G basitrich H basitrich I basitrich J microbasic p-mastigophore K small basitrich L large basitrich M microbasic p-mastigophore. Scale bar: 10 μm . Photographs by NWL Yap. Table 1. Cnidom of Phymanthus pinnulatus Martens in Klunzinger, 1877. Measurements in μm ; size outliers of single capsules are presented in values within parentheses. Abbreviations: N = the number of specimens having that type of cnidae to total specimens examined; n = total number of capsules measured for each type. Letters in parentheses following cnidae type refer to its illustration in Fig. 7.

Tissue	Cnidae	Phymanthus pinnulatus Martens in Klunzinger, 1877
		Range length x range width	N	n
p
p

Remarks. Of the 53 specimens collected in this study and those examined in situ, we encountered five individuals having reduced protuberances. These morphotypes were only encountered along the southern Singapore shores. While Klunzinger (1877) makes no mention of the etymology of the name, nor does it appear in Martens' (1867, 1875) reports, the original species name is rendered as pinnulatum , made up of both a noun (pinnula = small wing) and a neuter, adjective forming suffix (-tum), thereby making it an adjective in the nominative singular (ICZN Article 11.9.1). Therein, the original spelling of the species name is incorrect. The species name, being an adjective in a genitive case, according to Article 31.2 of the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature 1999), must agree in gender with the genus. The gender of Phymanthus is masculine, therefore the species name is pinnulatus (see also Fautin 2016 ).