BULLETIN OF MARINE SCIENCE, 51(3):315-328, 1992 FIVE NEW SPECIES OF MARINE GASTROTRICHA FROM THE ATLANTIC COAST OF FLORIDA Wayne A. Evans ABSTRACT Intertidal and subtidal sands from four locations along the Atlantic coast ofFlorida (Ma- tanzas Beach, Ormond Beach, Seagull Beach and Vilano Beach) yielded five new species of marine Gastrotricha. Acanthodasys silvulus new species and Paraturbanella aggregotubulata new species constituted the Macrodasyida; Neodasys ciritus new species, Chaetonotus sag- ittarius new species, and Ha/ichaetonotus bataceus new species comprised the Chaetonotida. Acanthodasys silvulus differs from its two congeners in the smaller size of the cuticular armature, the distribution of lateral adhesive tubes, and the size of the caudal appendages. Paraturbanella aggregotubulata possesses dorsal adhesive tubes, and has lateral adhesive tubes that areclumped inthe mid-trunk region. Neodasys ciritus.awell-known but previously undescribed species, isdistinguished bytwo columns ofpigmented-cells positioned along the lateral margins ofthe digestive tract that impart arusty-red color to the animal. It also lacks a caudal peduncle. Chaetonotus sagittarius and H. bataceus differ from their congeners pri- marily in the morphology and distribution of their cuticular armature. Gastrotrichs are a common component of the interstitial meiofaunal commu- nity inhabiting intertidal and subtidal marine sediments (Swedmark, 1964). While the Atlantic coast of Florida is replete with suitable habitat for gastrotrichs, only a few studies have been completed; notably those of Evans and Hummon (1991), Decho eta!. (1985), Ruppert and Shaw (1977), Hummon (1974), Schoepfer-Sterrer (1974), and Thane-Fenchel (1970). To date, 31 species ofmarine gastrotrichs have been reported from Florida. The examination of intertidal and subtidal sands from the Atlantic coast of Florida has revealed a rich gastrotrich fauna including five species which are new to science. METHODS The specimens described herein were taken from sediments collected during June, July, and Sep- tember, 1990 at Matanzas Beach, Ormond Beach, Seagull Beach, and Vilano Beach, Florida (Fig. I). Intertidal samples were taken by digging holes in the beach approximately 0.5 m deep at low tide and removing sediment from the walls ofthe hole with aplastic scoop. Sand obtained in this manner was placed into plastic bags. Subtidal samples were taken at a water depth of 2m during low tide by inserting a hand-held piston corer with adiameter of 2.5 em into the bottom sediment to adepth of approximately 12em. The sand in the corer was extruded into a plastic bag which was then sealed. Upon return to the laboratory, samples were stored at 14°Cto extend the life of the organisms. Gastrotrichs were extracted from the sediments by narcotization with isosmotic MgCI2, and then by subsequent rinsing ofthe sediments with seawater and decantation into 60-mm plastic Petri dishes. Individual living gastrotrichs were located by examining the supernatant fluid at 50x magnification under a Wild M-8 dissecting microscope and were removed by mouth pipette to a glass slide, on which then was mounted an 18-mm square coverslip supported by bits of non-toxic modeling clay on its corners. Further examination, drawing, and video recording of specimens were done under Nomarski dif- ferential interference contrast optics onaNikon LaboPhot IImicroscope. High-resolution video images were taken with an MTI CCD-72 camera (570-line resolution) with electronic image enhancement circuitry, and recorded with a Panasonic AG-1960 Super-VHS video recorder (400-1ine resolution). Drawings, made concurrently with image recording by means of a drawing tube, were transferred to AutoCAD 386 using a Kurta IS/ONE digitizing pad. The computerized images were modified and detailed within AutoCAD after reviewing the video images on an MTI 104100-01 black and white flat-field monitor (I,OOO-lineresolution), from which measurements could be made directly with a transparent rule. Abbreviations: An-anus, BrS-sensory bristle, CaB-buccal capsule, Cep-cephal- ion, CiA-anterior cilia, CiT-ciliary tuft, CiV-ventral cilia, Fu-furcal branches, GIE-epidermal 315 316 BULLETIN OF MARINE SCIENCE, VOL. 51,NO.3, 1992 '! Figure 1. Four sampling locations ontheAtlantic Coast ofFlorida. Intertidal and subtidal sediments weresampled at each location. Sediments are principally siliceous with small amounts of shellfrag- ments. gland, Hyp-hypostomium, In-intestine, LbC-caudallobes, Mo-mouth, Ov-ovum, Ph-phar- ynx, Pp-pharyngeal pores, RoF-frontal reproductive organ, Sc-scale, ScH-hydrofoil scale, Sp- sperm, Spn-spine, TbA-anterior adhesive tubes, TbD-"dohrni" tubes, TbL-lateral adhesive tubes, TbP-posterior adhesive tubes, Tn-tentacles, TrC-ciliary tract, Ts-testis. SYSTEMATIC SECTION Order Macrodasyida Rao and Clausen, 1970 Family Thaumastodermatidae Remane, 1927 Subfamily Diplodasyinae Ruppert, 1978 Genus Acanthodasys Remane, 1927 Acanthodasys si/vulus new species Figure 2 Holotype. - The adult specimen, 375 J.Lm in length, which is illustrated and rep- resented on Super-VHS format videotape [ICZN, 1985: Art. 72(c)(v)], but which is no longer extant. Seagull Beach, Florida (28°13'N, 80036'W); sandy subtidal sediments; July 1990. Copies of this high resolution (400-line) Super-VHS video recording and a lower resolution VHS (240-line) version have been deposited in the Ohio University Invertebrate Museum, Athens, Ohio and submitted to the National Museum of Natural History, Washington, D.C. Diagnosis. -Acanthodasys with cuticle densely covered with small (5 J.Lm) uni- ancres; all scales with spines. Buccal cavity large, rounded "V" in longitudinal- section. Mouth terminal; diameter less than width of head. Prominent pharyngeal pores with corresponding indentations in body wall. Four anterior adhesive tubes ventrally just behind mouth. Ten pairs of lateral adhesive tubes, with one pair anterior to pharyngeal-intestinal junction; two posterior-most pairs reduced in EVANS: FLORIDA MARINE GASTROTRICHA 317 Dorsal Ventral ~40 - ------- TbA -----..:: --»(,' .- Ph CiV --~ ~ ,- Pp - "'" I. [I ~l -~II ~ Ts ~ TbL ~f.- ::...--Sc II '~ If -5urn- -~~ --- In E .< ::l -- GIE 0 An -~I 0 ,I TbP" :\)Iff'~ A B Figure 2. Adult Acanthodasys silvulus n. sp.Dorsal cutaway view (A)ofinternal structures. Densely- packed uniancres cover dorsal and lateral surfaces. Ventral ciliary tracts (B)join both anteriorly and posteriorly. size. Distinct caudal lobes bear two adhesive tubes each. Ventral locomotor cilia in two, widely separated longitudinal rows that join near anterior and posterior ends. Etymology. -silvulus (L) diminutive of forest, after small, densely-packed uni- ancres. Description. - Body strap-shaped and rounded in cross-section; adults ranging in length from 345-430 and width from 47-53 (5 specimens); mouth 21-25 [.Lm [.Lm in diameter. Buccal cavity large, rounded V-shape in longitudinal-section. [.Lm Pharynx 110-120 long with prominent pharyngeal pores located near base [.Lm corresponding to marked indentations in body wall (Fig. 2A, B). Paired testes observed to begin just posterior to the pharyngeal-intestinal junction, tapering 318 BULLETIN OF MARINE SCIENCE, VOL. 51,NO.3, 1992 into vasa deferentia that continue posteriorly to mid-trunk regionwhere theyjoin, Frontal organ (Ruppert, 1978)posteriorly adjacent tojunction of vasa deferentia (Fig. 2A); caudal organ not observed. Ten to 12 pairs of irregularly-shaped epi- dermal glands distributed evenly along body. Trunk terminates with two caudal lobes about 10J.lm in length. Two narrow bands of ventral locomotor cilia, positioned near lateral margins of trunk, join just behind the mouth and anus (Fig. 2B). Dorsal ciliary band encircles the head. Cuticular armature consists of small, oval scales (uniancres) each with single erect spine about 5 ILm long (Fig. 2). Uniancres densely packed and of uniform size. Scales without spines not observed. Four equal-size (6-8 ILm in length) anterior adhesive tubes just posterior to rim ofmouth onventral side. Eightpairs oflateral adhesive tubes (10-12 J.lm inlength) spaced evenly along trunk from pharyngeal-intestinal junction to caudal lobes (Fig. 2A); one pair of these anterior to pharyngeal-intestinal junction. Two ad- ditional, smaller pairs of lateral adhesive tubes (6-8 J.lm in length) on trunk just anterior to caudal lobes; two unequal-length posterior adhesive tubes on distal end of each caudal lobe (Fig. 2B). Remarks. - Two speciesofAcanthodasys have been described to date, A. aculeatus Remane, 1927andA. arcassonensis Kisielewski, 1987.Ruppert (1978) mentioned fivespecies(A. diplodasyoides, A. tetranchyrodermatoides, A. vermiformis, A. thri- nax, and A. platydasyoides) that have never been illustrated or described and must be considered nomena nuda (Kisielewski, 1987).Acanthodasys silvulus dif- fers from A. aculeatus by having smaller, more abundant uniancres that are of a uniform size regardless of location on the body; A. aculeatus has uniancres that increase in sizeposteriorly. Acanthodasys aculeatus (asfigured by Remane, 1927, fig.5)has most of its lateral adhesive tubes grouped at the caudal end; however Fomeris (1961) shows a greater number and more even distribution of lateral adhesive tubes than Remane described (alsoseeKisielewski, 1987).Inthe author's experience (personal observations of specimens from the U.S.A. and Italy), A. aculeatus has about the same number oflateral adhesive tubes asA. silvulus, with several pairs of these clumped together near the base of the caudal lobes and two or more pairs anterior to the pharyngeal-intestinal junction (compared to I pair inA. silvulus). Additionally, the lateral adhesive tubes ofA. aculeatus are variable in length with the anterior-most tubes being the longest. Acanthodasys silvulus has a smaller mouth, fewer anterior and lateral adhesives tubes, and larger more robust caudal appendages than A. arcassonensis; A. silvulus also lacks scales with- out spines as occur on both A. aculeatus and A. arcassonensis. Acanthodasys silvulus was found in medium, siliceous sands in 1m of water at Seagull Beach, Florida. Family Turbanellidae Remane, 1925 Genus Paraturbanella Remane, 1927 Paraturbanella aggregotubulata new species Figures 3, 4 Holotype. - The adult specimen, 600 J.lm in length, which is illustrated and rep- resented on Super-VHS format videotape [ICZN, 1985:Art. 72(c)(v)],but which is no longer extant. Seagull Beach, Florida (28°13'N, 80036'W); sandy intertidal sediments; July 1990. Copies ofthis high resolution (400-line) Super-VHS video EVANS: FLORIDA MARINE GASTROTRICHA 319 Dorsal Venlral B CiA Mo TbD E A ~ o I 35um I o In c Figure 3. Adult Paraturbanella aggregotubulala n. sp. Internal organs and dorsal surface features (A) including evenly-spaced dorsal adhesive tubes and aggregated lateral adhesive tubes. Anterior adhesive tubcs are borne on fleshy "hands" (8); small "dohrni" tubes are inserted ventro-laterally just behind anterior tubes. Caudal lobes (C)are finelytapered with asingle row of 7adhesive tubes on each lobe. recording and a lower resolution VHS (240-line) version have been deposited in the Ohio University Invertebrate Museum, Athens, Ohio and submitted to the National Museum of Natural History, Washington, D.C. Diagnosis. -Paraturbanella with large, heavily cuticularized buccal cavity. Eight pairs of lateral adhesive tubes, with a single pair anterior to pharyngeal-intestinal junction, two pairs in mid-body region, and five pairs in close proximity to each other in posterior trunk region. Sixunequal-size anterior adhesive tubes on paired, ventral appendages. Small "dohrni"-type adhesive tubes. Six to 10pairs ofdorsal adhesive tubes. Seven posterior adhesive tubes in single row on each of two, tapered caudal lobes; small caudal cone present. Etymology. -aggregatus (L) clustering and tubulus (L) for clustering of the lateral adhesive tubes along trunk. Description. - Body strap-shaped with overall lengths ofadults (5specimens) rang- ing from 550-600 /-tm(Fig. 3A). Terminal mouth with diameter of 10/-tm;buccal cavity large (10 /-tmwide by 15 /-tmlong) and heavily cuticularized (Fig. 3B). Pharynx ranges from 190-210 ILm in length with prominent pharyngeal pores near base. Intestine terminates in ventral anus near base of finely tapered caudal lobes. Testes begin just posterior to pharyngeal pores, thence tapering into vasa 320 BULLETIN OFMARINE SCIENCE,VOL.51,NO.3, 1992 Ventral Dorsal CaB CiD TbA -BrS E :J. o LO A B Figure 4. Juvenile Paraturbanella aggregotubulata n. sp. have fewer adhesive tubes ofalItypes than do adults. Lateral adhesive tubes occur only in mid-trunk region. deferentia that continue posteriorly to mid-trunk where they tum anteriorly to base of testes and join ventrally at midline. Numerous pairs of lateral sensory bristles (15-20 ~m in length) occur along trunk from head to caudal lobes. Caudal lobes finely tapered (Figs. 3C, 4A). Small caudal cone (2-4 ~m in length) present between caudal lobes (Fig. 3C). Cone present in both subadults and juveniles (Fig. 4A). Ventral locomotor cilia cover the entire surface of pharyngeal region and posterior end, but form two broad, longitudinal bands on trunk. Sparse anterior ciliary band present on head (Fig. 3A). Ventral adhesive tubes borne on short, fleshy appendages ("hands"). Each hand bears six unequal-length tubes (2-6 ~m in length) in adults (Fig. 3B)with medial- most tube much smaller than others. Subadults and juveniles have fewer (2-4) tubes on each appendage (Fig. 4A). Additional ventral adhesive tubes in anterior trunk region consist of pair of unequal-length tubes known as dohrni tubes (Re- mane, 1927 and see Evans and Hummon, 1991) that are inserted just posterior to ventral hands (Fig. 3B).Longer tube ofeach pair 10-12 ~m in length and shorter EVANS: FLORIDA MARINE GASTROTRICHA 321 tube 6-8 Mmin length in adults. Lateral adhesive tubes (10-15 Mmin length) consist ofeight pairs inserted ventrolaterally; a singlepair anterior to pharyngeal- intestinal junction, two widely-spaced pairs in mid-trunk region, and remaining fivepairs clustered together in posterior trunk region (Fig. 3A). Dorsal adhesive tubes (8-10 Mmin length) consist of8-10 pairs that begin at pharyngeal-intestinal junction and terminate at same level as lateral adhesive tubes (Fig. 3A). Seven posterior adhesive tubes of unequal-length (6-12 Mm)in single row borne on posterior margin of each caudal lobe. Subadults and juveniles have fewer tubes of all types (Fig. 4B). Remarks. - There are presently 10species inthe genusParaturbanella. Important taxonomic characters for this genus include 1)size, shape and degree of cuticu- larization of the buccal cavity, 2) presence/absence, number and distribution pattern of the adhesive tubes, 3)size and shape of the dohrni tubes, 4) presence/ absence and sizeofthe caudal cone, and 5)ventral ciliary pattern. Paraturbanella aggregotubulata most closely resembles P. eireanna Maguire, 1976 and P. inter- media Wieser, 1957in general body shape, and in sizeand cuticularization ofthe buccal cavity. Paraturbanella aggregotubulata differs from both of these species byhaving 1)shorter dohrni tubes, 2)dorsal adhesive tubes, and 3)lateral adhesive tubes clustered inthe mid-trunk region. Paraturbanella aggregotubulata has fewer posterior adhesive tubes than P. intermedia and possesses a caudal cone (absent in P. eireanna). Paraturbanella armoricana (Swedmark, 1954), and Kisielewski (1987) has dorsal adhesive tubes and shows a small degree ofclustering oflateral adhesive tubes, but differs from P. aggregotubulata in having 1)fewer (5 vs. 6) anterior adhesive tubes, 2) a double row of posterior adhesive tubes, and 3) a narrower constriction ofthe trunk near the baseofthe caudal lobes.Paraturbanella armoricana also lacks a caudal cone and the heavy buccal cuticularization char- acteristic of P. aggregotubulata. P. aggregotubulata was found at all sampling locations and in both subtidal and intertidal siliceous sands. Order Chaetonotida Rao and Clausen, 1970 Suborder Multitubulatina d'Hondt, 1971 Family Neodasyidae Remane, 1929 Genus Neodasys Remane, 1927 Neodasys ciritus new species Figure 5 Holotype. - The adult specimen, 480 Mmin length, which is illustrated and rep- resented on Super-VHS format videotape [ICZN, 1985:Art. 72(c)(v)],but which is no longer extant. Ormond Beach, Florida (29°17'N, 80059'W); sandy intertidal sediments; September 1990. Copies ofthis high resolution (400-line) Super-VHS video recording and a lower resolution VHS (240-1ine)version have been depos- ited in the Ohio University Invertebrate Museum, Athens, Ohio and submitted to the National Museum of Natural History, Washington, D.C. Diagnosis. -Neodasys with goblet-shaped, heavily-cuticularized buccal capsule extending beyond mouth. Digestive tract bordered by two longitudinal rows of globular, red-pigmented cells.Distinct furcalbranches with squared tips;not borne on peduncle. Ventral locomotor cilia in two broad longitudinal rows that join near anus. Clump ofseveral longer cilia in interciliary fieldnear caudal end. Head with two lateral lobes bearing cilia and sensory bristles. Lateral sensory bristles sparse. 322 BULLETIN OF MARINE SCIENCE, VOL. 51,NO.3, 1992 Eg B A ------ Sb HbC In Ov I\n --- __ E CiT :J. o o Fu Figure 5, Adult Neodasys ciritus n, sp. Red-pigmented cells bordering the digestive tract (A) have been reported to contain hemoglobin; long tuft of ventral cilia occurs near posterior end, Goblet- shaped buccal capsule (B)isheavily cuticularized and projects anteriorly beyond head. Furcal branches (C)bear sensory bristles and have squared tips. Etymology. - Ciritus (L) for small beard, referring to the patch of unusually long ventral cilia. Description. -Adult specimens (5 specimens) ranged from 460-520!lm in length; body of uniform width (42-48 !lm). Heavily cuticularized buccal capsule leads to short pharynx (130-140 !lm), thence to intestinal tract which terminates in ventral anus near posterior end of trunk (Fig. 5C). Digestive tract bordered dorsolaterally by rectangular and cuboidal cells (Y-cells) in one or two layers from mid-pha- ryngeal region to termination of intestine. Six small epidermal glands, on each side of digestive tract, uniformly distributed from head to posterior end of trunk (Fig. 5A, B). Caudal appendages 28-30 !lm in length with squared tips. Two lateral lobes on head covered with numerous short cilia and several longer sensory bristles (Fig. 5B);lateral sensory bristles continue to tip offurcal branches. Ventral locomotor cilia in two wide longitudinal bands; separate on head and trunk, confluent from near anus to furca. Unusual tuft of long (about 40 !lm), ventral cilia in interciliary fieldjust anterior to confluence of ventral ciliary bands (Fig. 5A). Remarks. -Neodasys ciritus, the "red" gastrotrich, has a long history in the gas- trotrich literature and has been described as Neodasys sp. by several workers EVANS: FLORIDA MARINE GASTROTRICHA 323 (Colacino and Kraus, 1984; Kraus and Colacino, 1984; Ruppert, 1982, 1978, 1977;Ruppert and Hogue, 1978;Ruppert and Travis, 1983;Travis, 1983),while other workers have erroneously referred to itasN. chaetonotoideus Remane, 1927 (Rieger, 1976; Rieger and Rieger, 1977; Hummon, 1969). Hummon (1969) gives a detailed description of adult and subadult specimens found in Massachusetts beaches, describing the red-pigmented cells as lying in two longitudinal bands adjacent to the digestive tract. He also describes the re- productive system and sperm morphology. Ruppert (1977) includes drawings and photomicrographs of both whole animals and of the reproductive system, spe- cificallythe testes and spermatozoa. He describes the red-pigmented cellsas "Y- cells," compares Neodasys sp. and N. uchidai Remane, 1961with respect to their general morphology, and provides information on the ecologicaland geographical distributions of both species. Kraus et al. (1981) were the first to show that the red color in Neodasys sp. is due to the presence of hemoglobin in the Y-cells. Ruppert and Travis (1983) give the most complete description of Neodasys sp. todate and include adetailed cytological description ofthe hemoglobin-containing cells. They also give a brief history of red coloration in meiobenthic organisms. Their description ofthis species, and that of Ruppert (1977) are in general agree- ment with my observations of N. ciritus. However, no previous workers have observed the tuft oflong ventral cilia, probably due to the fact that these cilia are only visible in a lateral view of the animal (seldom obtained with a glass slide and cover slip preparation). Colacino and Kraus (1984) conducted oxygen transport and uptake studies on Neodasys sp. and concluded that simple diffusion of oxygen through the body wall is sufficient to meet the metabolic needs of an active Neodasys, speculating that the hemoglobin-cells store oxygenforusewhen Neodasys findsitselfin anoxic sediments. Neodasys ciritus was very common both intertidally and subtidally at all sampling locations in this study, but was never observed in sediments which appeared to be anoxic. Neodasys ciritus differs from N. chaetonotoideus and N. uchidai by having 1)a large, goblet-shaped and heavily cuticularized buccal capsule, 2)two longitudinal rowsofhemoglobin-containing Y-cellsthat impart arusty-red color tothe animal, 3)atuft oflong, ventral cilia,and 4)broader longitudinal rowsofventral locomotor cilia. Neodasys ciritus also lacks the caudal peduncle of N. uchidai. Neodasys uchidai has been reported ashaving red-pigmented Y-cells(Ruppert, 1977;Rieger et al., 1974; Teuchert, 1974), but these were not noted in Remane's (1961) de- scription ofthe type specimen forthis species. The Y-cellsdescribed forN. uchidai by Ruppert (1977) appear to be larger and less numerous than in N. ciritus; the anterior-most pair ofY-cellsinN. ciritus differsfrom those described forN. uchidai inbeingelongated and squamous (Fig.5B).Neodasys uchidai hasnot beenreported from North America. Suborder Paucitubulatina d'Hondt, 1971 Family Chaetonotidae Zelinka, 1889 Genus Chaetonotus Ehrenberg, 1830 Chaetonotus sagittarius new species Figure 6 Holotype. - The subadult specimen, 180 in length, which is illustrated and j.Lm represented on Super-VHS format videotape [ICZN, 1985: Art. 72(c)(v)], but which is no longer extant. Vilano Beach, Florida (29°55'N, 81°17'W); sandy sub- 324 BULLETIN OF MARINE SCIENCE, VOL. 51,NO.3, 1992 Dorsal CiV - In - -- Sc BrS Sp Fu A Figure 6. Adult Chaetonotus sagittarius n.sp. Dorsal scales (A)possess asingle, robust spine. Spines increase in size from midline toward lateral margins. Ventral scales (B)are arranged in oblique rows oftwotofour spines each; fouradditional ventral scaleswith keelsoccur atjunctions offurcal branches. tidal sediments; June 1990. Copies of this high resolution (400-line) Super-VHS video recording and a lower resolution VHS (240-line) version have been depos- ited in the Ohio University Invertebrate Museum, Athens, Ohio and submitted to the National Museum of Natural History, Washington, D.C. Diagnosis. -Chaetonotus with well-rounded, unlobed head and sub-terminal mouth; small cephalion present. Seven to 10longitudinal rows of elliptical dorsal scales with 26-28 scales per row. Simple, curved spine on each scale has robust, half-moon shaped base tapering to sharp point at tip ofspine. Single spine without associated scale on posterior trunk near caudal furca. Oval ventral scales with spines arranged in oblique rows of two (head), three (neck), and four (trunk). Two pairs of single-keeled scales on ventral posterior end. Oval scale with short, pos- terior spine on medial edge of each furcal branch. Etymology. -sagittarius (L), denoting arrows, after the quiver-like arrangement of ventral spines.