Common names: Rock Boring Urchin
Synonyms: Echinus lucunter Linnaeus, 1758
Species Description: The rock boring urchin, Echinometra lucunter, has an elongate oval test with two rows of large tubercles along the ambulacra and interambulacra, pairs of pores arranged in arcs of six, and a large peristome (Hendler et al. 1995). The spines are long and slender, thickened at the base, and sharply pointed at the tips.
On the aboral side, the primary and secondary spines are dark olive green, with greenish violet to purple tips (Hendler et al. 1995). The general color of the spines is blackish, although some specimens may exhibit a reddish color. Test and muscle bases of the spines are shades of red-brown. Tube feet on the aboral surface are light brown, and the terminal disks are dark brown to blackish. Oral spines have a lighter color than aboral ones, light olive green with a violet gradient near the tips. The test and peristome are flecked with creamy brown. The tube feet near the mouth are translucent, with terminal disks that are creamy white in color, lined with a narrow dark brown band, and measuring about twice the size of those on the aboral feet.
As with many intertidal organisms, studies have revealed differences in the structure of E. lucunter from environments with varying wave action. Specimens from high-energy areas tend to have tests that are flatter, thicker, smaller, and narrower, and a distinctive pattern of insertion of ocular plates in the apical system (Lewis & Storey 1984).
Potentially Misidentified Species: The general shape and size of E. lucunter is similar to that of the reef urchin, E. viridis. However, the latter usually has a more circular test shape and longer spines, a reddish test, pore pairs in arcs of five instead of six, and conspicuously white milled rings around the base of each spine (Hendler et al. 1995).
Habitat & Regional Occurrence: The rock-boring urchin is commonly found on limestone reef rock in the surf zone (Hendler et al. 1995). It can be very common in shallow, exposed fore reef or reef crest habitats, occupying shallow depressions or burrows created by the abrading action of the urchin’s spines and teeth on the rock surface. The success of E. lucunter in harsh environments may be partially due to its apparent resistance to stresses caused by increased temperature and salinity (Hendler 1977).
The range of E. lucunter extends from Beaufort, North Carolina and Bermuda southward throughout the Caribbean and eastern Central America to Desterra, Brazil. Populations can also be found in West Africa. The subspecies E. lucunter polypora Pawson is common at Ascension and St. Helena Islands (Pawson 1978). The depth range for this species is generally zero to 45 meters (Serafy 1979).
Indian River Lagoon Distribution: The distribution of E. lucunter within the IRL remains undocumented. However, this species appears to be concentrated mostly around rock jetties and other hard structures near inlets (LH Sweat, personal observation).
Size: E. lucunter reaches a maximum size of 15 cm, though most individuals are about half that size (Hendler et al. 1995).
Abundance: The abundance of E. lucunter in the IRL is undocumented. However, studies have reported densities elsewhere of up to 129 individuals per square meter (Greenstein 1993).
Reproduction & Embryology: The annual spawning cycle for the rock-boring urchin has been reported to occur in late summer in the Florida Keys (McPherson 1969), peaks in the fall in Puerto Rico (Cameron 1986), and occurs variably throughout the year in Panama (Lessios 1981). Lewis & Storey (1984) documented one spawning event per year in urchins from high-energy environments, and two events annually in urchins from low-energy areas. Tennent et al. (1931) reported that spawning in one individual takes about 15 minutes. Fertilization and development are adversely affected by reducing salinity (Petersen & Almeida 1976). Larvae of this species have been reared through metamorphosis in the laboratory (e.g. Mortensen 1921).
Trophic Mode: The rock-boring urchin feeds mostly at night from their burrows, consuming clumps of drift algae, or venturing out of the burrow to feed and then usually returning to the same hole (McPherson 1969, Abbott et al. 1974, Ogden 1976). In Panama, individuals were observed to clear the area around their burrows of all organisms except calcareous algae (Hendler et al. 1995).
Movement & Behavior: Antagonistic behaviors among conspecifics have been observed for this urchin. Grunbaum et al. (1978) found that intruding urchins were pushed and bitten by the individual originally inhabiting the burrow, and that the inhabitant won most altercations. Escape responses have been observed in individuals following exposure to chemical extracts from other Echinometra spp. (Parker & Shulman 1986).
Predators: Predators of E. lucunter include: ruddy turnstones, Arenaria interpres; conchs; and fish including triggerfish, grunts, jacks and wrasses (Abbott et al. 1974). Predation by the reticulate cowrie-helmet, Cypraecassis testiculus, has also been documented for individuals in Panama (Hendler 1977).
Parasites & Associated Species:: The eulimid gastropod, Monogamus minibulla is a parasite of the rock-boring urchin (Warén & Moolenbeek 1989). The turbellarian, Syndisyrinx collongistyla, has been reported to infest the intestines of E. lucunter in Jamaica, S. evelinae has been found in specimens from St. Barthélemy (Hertel et al. 1990). Protozoans have also been reported to infest E. lucunter (Mortensen 1943). The rock-boring urchin has been observed to share its burrow with several associates, including a goby, a porcelain crab, and a brittle star (Schoppe 1991).
Ecological Significance: The burrowing behavior of E. lucunter can contribute greatly to the breakdown of coral reefs and intertidal limestone shorelines, especially when urchin population densities are high. Hoskin & Reed (1985) estimated that burrows are excavated in approximately 3 years. Rates of erosion on coral reefs due to this excavation have been reported at 3.9 kg per square meter annually in the Virgin Islands, 7.0 kg per square meter annually in Bermuda, and 24 g per urchin per year in Barbados (Ogden 1977).
Ablanedo et al. (1990) found that individuals of E. lucunter accumulate certain heavy metals in the gonads, test, spines, and lantern. Therefore, they can be used as an indicator species to reflect the level of environmental pollution to which they are exposed.
Abbott DP, Ogden JC & IA Abbott. 1974. Studies on the Activity Pattern, Behavior, and Food of the Echinoid Echinometra lucunter (Linnaeus) on Beachrock and Algal Reefs in St. Croix, U.S. Virgin Islands. West Indies Laboratory Special Publication No. 4. Fairleigh Dickinson University. Christiansted, St. Croix. U.S. Virgin Islands. iv + 111 pp.
Ablanedo N, Gonzalez H, Ramirez M & I Torres. 1990. Evaluación del erizo de mar Echinometra lucunter como indictor de contaminación por metales pesados, Cuba. Aquat. Living Res. 3: 113-120.
Cameron RA. 1986. Reproduction, larval occurrence and recruitment in Caribbean sea urchins. Bull. Mar. Sci. 39: 332-346.
Greenstein BJ. 1993. Is the fossil record of regular echinoids really so poor? A comparison of living and subfossil assemblages. Palaios 8:587-601.
Grunbaum H, Bergman G, Abbott DP & JC Ogden. 1978. Intraspecific agonistic behavior in the rock-boring sea urchin Echinometra lucunter (L.) (Echinodermata: Echinoidea). Bull. Mar. Sci. 28: 181-188.
Hendler G. 1977. The differential effects of season stress and predation on the stability of reef-flat echinoid populations. In: Taylor DL (Ed.). 217-223. Proceedings: Third International Coral Reef Symposium. Volume 1 (Biology). Rosenstiel School of Marine & Atmospheric Science, University of Miami. Miami, Florida.
Hendler G, Miller JE, Pawson DL & PM Kier. 1995. Sea stars, sea urchins, and allies: echinoderms of Florida and the Caribbean. Smithsonian Institution Press. Washington, D.C. 390 pp.
Hertel L, Duszynski DW & JE Ubelaker. 1990. Turbellarians (Umagillidae) from Caribbean urchins with a description of Syndisyrinx collongistyla, n. sp. Trans. Amer. Microscop. Soc. 109: 272-281.
Hoskin CM & JK Reed. 1985. Carbonate sediment production by the rock-boring urchin Echinometra lucunter and associated endolithic infauna at Black Rock, Little Bahama Bank. Symposia Ser. Underwater Res. 3: 151-161.
Lessios HA. 1981. Reproductive periodicity of the echinoids Diadema and Echinometra on the two coasts of Panama. J. Exp. Mar. Biol. Ecol. 50: 47-61.
Lewis JB & GS Storey. 1984. Differences in morphology and life history traits of the echinoid Echinometra lucunter from different habitats. Mar. Ecol. Prog. Ser. 15: 207-211.
McPherson BF. 1969. Studies on the biology of the tropical sea urchins Echinometra lucunter and Echinometra viridis. Bull. Mar. Sci. 19: 194-213.
Mortensen T. 1921. Studies of the development and larval forms of echinoderms. G.E.C. Gad. Copenhagen, Denmark. xxxiii + 266 pp.
Mortensen T. 1943. A Monograph of the Echinoidea. Volume III. (3). Camarodonta. I. Orthopsidae, Glyphocyphidae, Temnopleuridae and Toxopneustidae. CA Reitzel, Copenhagen. vii + 553 pp. 56 pls.
Ogden JC. 1976. Some aspects of herbivore-plant relationships on Caribbean reefs and seagrass beds. Aquat. Botany 2: 103-116.
Ogden JC. 1977. Carbonate-sediment production by parrotfish and sea urchins on Caribbean reefs. Stud. Geol. 4: 281-288.
Parker DA & MJ Schulman. 1986. Avoiding predation: Alarm responses of Caribbean sea urchins to simulated predation on conspecific and heterospecific sea urchins. Mar. Biol. (Berlin) 93: 201-208.
Pawson DL. 1978. The echinoderm fauna of Ascension Island, South Atlantic Ocean. Smithsonian Contrib. Mar. Sci. 2. iv + 31 pp.
Petersen JA & AM Almeida. 1976. Effects of salinity and temperature on the development and survival of the echinoids Arbacia, Echinometra and Lythechinus. Thalassia Jugoslavia 12: 297-298.
Schoppe S. 1991. Echinometra lucunter (Linnaeus) (Echinoidea, Echinometridae) als Wirt einer komplexen Lebensgemeinschaft im Karibischen Meer. Helgoländ. Meeresunt. 45: 373-379.
Serafy DK. 1979. Echinoids (Echinodermata: Echinoidea). Memoirs of the Hourglass Cruises 5: 1-120.
Tennent DH, Gardiner MS & DE Smith. 1931. A cytological and biochemical study of the ovaries of the sea urchin Echinometra lucunter. Carnegie Institution of Washington Publication No. 27. 1-46. pls. 1-7.
Warén A & R Moolenbeek. 1989. A new eulimid gastropod, Trochostilifer eucidaricola, parasitic on the pencil urchin Eucidaris tribuloides from the southern Caribbean. Proc. Biol. Soc. Wash. 102: 169-175.
Aboral: In a direction away from the mouth; the part of the body opposite the mouth.
Anal Cone: In crinoids and echinoids, a fleshy projection bearing the anus at its apex; also known as an anal tube.
Apical System: In echinoids, a ring of specialized skeletal plates, including the genital plates and ocular plates; usually located on the highest point of the test.
Arm: In asteroids, crinoids, and ophiuroids, a movable, jointed ambulacral projection, distal to the disk or calyx that carries a radial branch of the water vascular system and the nervous system; sometimes called a ray.
Basket: One of several types of microscopic skeletal ossicles in holothuroids; minute cup-shaped ossicle, usually with four projections.
Button: One of several types of microscopic skeletal ossicles in holothuroids; minute ossicle with four perforations; may be smooth or knobbed.
Disk: The round or pentagonal central body region of ophiuroids and asteroids; see also Terminal Disk.
Distal: In a direction away from the center of the body; for example, toward the tip of the arm in asteroids or the tip of a spine in echinoids.
Dorsal: In echinoderms, this term is variously applied; in asteroids, ophiuroids and echinoids it usually refers to the surface of the body that is opposite the mouth, the surface that is uppermost; in holothuroids, with mouth and anus opposite ends of the cylindrical body, the uppermost surface is considered dorsal; in crinoids, the surface opposite the mouth in considered dorsal by convention, even though it is functionally the ventral (lower) side.
Echinulate: Something spiny or prickly, usually referring to the microscopic texture of a skeletal element such as a spine.
Hermaphrodism: A condition in organisms whereby one individual possesses both functional male and female reproductive structures; hermaphroditic individuals may express both sexes simultaneously, alternately, or sequentially.
Interambulacral Area: An oral or aboral section of the body lying between two ambulacra; in interradius; also known as an interambulacrum.
Interradial: Referring to interambulacral areas of the body; interradius and interradii also commonly used.
Oral: In a direction toward the mouth; a part of the body on the same surface as the mouth.
Oral Papillae: In ophiuroids, small plates at the edge of the mouth, attached to the edges of the jaw plate and/or to the aboral shield; may be variously shaped, from spine-like to scale-like.
Papillae: In holothuroids, specialized dorsal tube feet that lack a suckered tip; in ophiuroids, certain skeletal elements of the jaws or disk.
Papillate: Covered with papillae.
Papillose: Covered with papillae.
Pedicellariae: Small stalked or unstalked pincer-like organs on the body of asteroids and echinoids, used for defense and grooming.
Peltate: Shield-shaped; used to describe the tentacles of some holothuroids.
Perforated Plate: One of several types of microscopic skeletal ossicles in holothuroids; sieve-like and widespread; may also be found in other echinoderm classes, especially in juvenile individuals.
Periproct: In echinoids, a flexible region surrounding the anus, which consists of a membrane containing embedded plates and often bearing spines and pedicellariae.
Plates: One of several types of skeletal elements in echinoderms; tabular structures with a characteristic shape and a fixed position.
Primary Plates: The first-formed plates on the dorsal side of the disk; in ophiuroids, these are the central and five radial plates; in adults, they may form a rosette of scales near the center of the disk, or they may be separated by numerous secondarily developed scales.
Radial: In a direction toward the central axis of an arm or ambulacrum; a part of the body near an arm or ambulacrum.
Radial Shields: Pairs of plates on the dorsal surface of the ophiuroid disk, which lie near the base of each arm; usually relatively large and conspicuous, but may be hidden by granules or superficial scales.
Rods: One of several types of microscopic skeletal ossicles in holothuroids; commonly found as supporting structures in tentacles or tube feet.
Scales: One of several types of skeletal elements in echinoderms; flat, thin structures that are overlapping, tessellate, or haphazardly arrayed.
Sole: In some holothuroids, the flattened ventral part of the body, either covered with or surrounded by tube feet.
Spines: One of several skeletal elements in echinoderms; movable, articulating structures that are long, slender and attenuated.
Teeth: In ophiuroids, small plates or spines attached to the dental plate on the inner edge of the jaw, a series of them extending into the mouth; in echinoids, the five hard, sharp, and movable ossicles incorporated in Aristotle’s lantern; the term also refers to five movable ossicles that surround the anus of some holothuroids.
Tentacle Scales: Small, movable spines or scales, associated with ophiuroid tube feet, which are attached to the ventral arm plate and/or lateral arm plate; may cover the tentacle pores and protect the retracted tube feet.
Tentacles: In holothuroids, feeding structures in the form of highly modified tube feet arranged in a ring around the mouth.
Terminal Disk: Round portion on the end of the tube foot in many echinoderms; usually employed for attachment to substrates.
Tube Feet: Fluid-filled, fingerlike extensions of the water vascular system that protrude through the openings in the skeleton or between skeletal elements; muscles and nerves in the shaft of the tube feet control their movements; glands, and sometimes a muscular sucker, at the tip function in adhesion; specialized tube feet are used for locomotion, feeding, burrowing, respiration, and a combination of functions.
Ventral: In echinoderms, this term is variously applied; in asteroids, echinoids and ophiuroids, it is the surface of the body that carries the mouth; this surface is in contact with the substrate; in holothuroids, with mouth and anus at opposite ends of a cylindrical body, the ventral surface is lowermost, in contact with the substrate; in crinoids, the ventral surface carries the mouth and is functionally the uppermost surface.