MARINE FAUNA AND FLORA OF BERMUDA A Systematic Guide to the Identification of Marine Organisms Edited by WOLFGANG STERRER Bermuda Biological Station St. George's, Bermuda in cooperation with Christiane Schoepfer-Sterrer and 63 text contributors A Wiley-lnterscience Publication JOHN WILEY & SONS New York * Chichester • Brisbane • Toronto * Singapore PORIFERA 111 stomulida {p. 211), Gastrotricha (p. 213), and brown are commonly caused by sym- Nematoda (p. 216), Rotifera (p. 219), biotic algae. Sponges are crustose or mas- Kinorhyncha (p. 220), Priapulida {p. 222), sive, cushion-, fan-, tube-, tree- or cup- Acanthocephala (p. 223), Sipuncula (p. shaped. Attached to the substrate, they 224), Echiura (p. 228), Pogonophora (p. show little movement except contraction of 230), Annelida (p. 232), Tardigrada (p. the entire body or of the openings upon 265), Arthropoda (p. 268), Mollusca (p. disturbance. They are most commonly 392), Bryozoa (p. 500), Phoronida (p. 516), confused with compound ascidians. Brachiopoda (p. 518), Chaetognatha (p. 519), Echinodermata (p. 522), Hemichor- Of the 4 recent sponge classes, the reef- data{p. 541), and Chordata (p. 545). The 5 dwelling Sclerospongea have hitherto not phyla not represented are the microscopic, been found in Bermuda, and Hexactinel- primitive, marine Placozoa, Nematomor- lida occur in the deep sea. Owing to many pha (nema lode-like worms with few new data on embryology, histology and marine representatives), the recently de- chemistry, the positions of higher taxa re- scribed marine interstitial Loricifera, the main in a state of llux. Of about 5,000 terrestrial Onychophora and the parasitic species known, 70 (approximately, because Pentastomida. Recent phylogenetic anal- of many uncertain identifications) are yses support the subdivision of Metazoa found in Bermuda; 49 are reported here. into Piacozoa, Parazoa ( = Porifera) and Eumetazoa (all other phyla), and the latter OCCURRENCE: Predominantly marine (3 into Coelenterata (= Radiata, i.e., Cnidaria Demospongea families in fresh water, but and Ctenophora) and Bilateria. Only the none reported from Bermuda), on stable latter term is used for classification pur- substrates, Calcarea are most common in poses here (p. 197). very shallow water; Demospongea (95% of all recent species) occur in all depths and climatic zones but, except for small, crus- Phylum Porifera (Sponges) tose and endolithic forms, avoid high- energy environments. Substrates include CHARACTERISTICS: Sedentary, aquatic, rock (particularly in caves), dead coral, filter-feeding METAZOA bounded by a 1-cell subtidal mangrove roots, sea grass layer of flat pinacocytes (pinaeoderm) and con- rhizomes, algae, other sponges, shells of taining flagellated choanocytes (choanoderm) mollusks and crabs, and artificial struc- that create a unidirectional water current, tures (buoys, pilings). Soft bottoms in calm through the body. Water enters numerous water are colonized by initial settlement on small ostia (pores) and leaves through larger rubble fragments. oscula. Mesohyle (between pinaeoderm and Collect by wading, snorkeling or choanoderm) contains various mobile cells, col- SCUBA diving (turn over rocks, look in- lagen and, usually, a skeleton of spongin, min- side caves); on deep level bottoms also by eral (silica or calcium carbonate) or both. The dredging. Cut with knife or chisel; include size ranges from millimeters to more than substrate where possible (with encrusting 1 m diameter, commonly 0.1-10 1 in or excavating forms in particular). Wear volume. Consistency varies with nature gloves for some forms are irritating to the and density of the skeleton from soft skin (by s pic tiles, toxins or epizoic cnida- crumbly to stiff elastic and stony hard. Col- rians). Commercially usable species have ors are often vivid (yellow, red, blue), par- been reported from Bermuda but are now ticularly in dark locations; shades of green very rare or absent. Other forms are under 112 KINGDOM ANIMALIA investigation for their antimicrobial prop- structures include exhalant openings (oscula), protru- erties. sions (conuli, papillae), embedded sand grains and special spiculous reinforcements (cortex). The sur- IDENTIFICATION: Some species can be face layer (ectosome) covers an internal layer identified from color, shape, consistency (choanosome) that contains skeletal material and is traversed by canal systems. Three types of canal sys- and surface structures. These characters tems are recognized in sponges; all occur in Calcarea. should be noted from fresh specimens, to- A scon is a simple lube (spongocoel) lined with gether with possible presence of pigment choanocytes (choanoderm), e.g., in Ctatkrina. Sycon, exudate or color changes shortly after named after the sponge where it occurs, has a folded collecting. Color photographs for doc- choanoderm; the choanocytes line short tubes that radiate from a common atrium, l.eucon occurs in umentation are useful if immediate many Calcarea (e.g., Leutandra) and in all Demo- identification is not possible. Presence and spongea; the choanocytes are restricted to small type of skeleton should be determined chambers that are dispersed through the thick from microscope preparations. Make 0.2- mesohyl; the choanocyte chambers are connected to 0.5 mm sections (razor blade) of dehy- each other and to the outside by a system of canals without flagellated cells. drated (alcohol or air dried) material; cut Note reticulation and structure of spongin fibers, perpendicular and, subsequently, parallel and mineral composition, size classes, position and to the surface and note whether a surface type (shape) of spicules. Collagenous spongin can oc- layer (ectosome) is detachable from the in- cur as patches connecting spicules or it can build up a ternal layer (choanosome); clear in xylene substantial elastic framework. Skeleton structure can be reticulate (net-like), with ascending primary and and mount in balsam under cover glass. connecting secondary fibers, dendritic (tree-like Alcohol-hardened material can also be branching) or intermediate such as dend roreticulate stained to make soft tissue components or pi u mo reticulate (feather-like). Spongin fibers can (e.g., spun gin, choanocyle chambers) bet- be clear or cored by a pith, by sediments, or by ter visible. A convenient stain for this pur- spicules. Spongin fibrils (In.iniu) and spongin spicules (DartiiineUa) are structures not connected to the pose is a saturated solution of basic fuchsin framework. Most sponge spicules are siliceous, except in 95% ethanol; rinse well with alcohol. in Calcarea where they are of calcium carbonate (test Spicules are isolated by digesting small but with acid!). One distinguishes megascleres (com- representative tissue fragments in cold monly >5(l p.m) that are structurally important, and sodium hypochlorite (C lor ox) or (siliceous microsclcrcs that occur tin oriented in certain parts of the tissue, Megascleres can be arranged in radiate, spicules only) boiling nitric acid; examine reticulate or felted fashion, in strands, coring (fully under high-power optics. Permanent embedded), or echinating (partly embedded in) spon- mounts of dry spicules in balsam require gin fibers. Megascleres can have I (monaxon), 3 thorough rinsing with water and absolute (triaxon) or 4 (letraxon) axes. Monaxon forms can be alcohol. Let spicules settle in test tube after pointed at both ends (oxea); pointed at one end, rounded at the the other (style); rounded at both each change (minimum 1 hr in water, 0.5 (strongyle); pointed at one, knobbed at the other (ty- hr in alcohol) to prevent loss of mi- lostyle); or knobbed at both ends (tylote). Cladolylotes croseleres. Use standard histological tech- are tylote at one end, anchor-like with recurved dads niques to determine shape, size and ar- (rays) at the other. Spitted spicules have the prefix rangement of choanocytes and choanocyte acantho- (e.g., acanthostyle). Monactines, diactincs, triactines and tetractines chambers for classification of some Kera- are radiate spicules with 1-4 rays, respectively. tosa and Calcarea. Triaenes are tetractines with 1 ray (rhabd) commonly Common sponge shapes are crustose, chambered much larger than the other 3, which can point for- (excavating), irregularly massive, spherical, tubular ward of (protriaeu) or toward (anatriacn) the rhabd. or cylindrical. Most colors are represented, but fade Desmas are irregular complex branching and inter- or change quickly after collecting (especially when ex- locking megascleres. Microscleres can be various posed to air), even before preservation. Consistency forms of asters where rays originate from 1 point can be mucous son, compressible, elastic, stiff, car- (euaster) or from an axis (strcptaster). Euasters in- tilaginous or hard and brittle. Conspicuous surface clude those with long free tapered rays (oxyasler). PORIFERA 113 with short ray and thick centrum (spheraster) and formed by some species (e.g., Utosa ruetz- with coalescenl rays and special surface ornamenta- leri, Cliona lampa). Life-span ranges from a tion (sterraster). The most common kind of strep tas- few months to about 10 yr; some very large ter has a s pi r;iled axis and is termed s pi raster. A re- lated type, the amphiaster, has spines radiating from (0.8-2.5 m diameter) specimens of Demo both ends of the shaft. Microsderes can also be hair- spongea observed in deep reef zones, out- like (i aphid), C- or S-shaped (sigma; sigmaspire, if side the range of wave action, are es- contorted) or bow-shaped