Balanus Glandula Class: Multicrustacea, Hexanauplia, Thecostraca, Cirripedia

Home , Archaeobalanidae, Balanidae, Balanomorpha, Balanus, Balanus balanus, Balanus crenatus

Phylum: Arthropoda, Crustacea

Balanus glandula Class: Multicrustacea, Hexanauplia, Thecostraca, Cirripedia

Order: Thoracica, Sessilia, Balanomorpha Acorn barnacle Family: Balanoidea, Balanidae, Balaninae

Description (the plate overlapping plate edges) and radii Size: Up to 3 cm in diameter, but usually (the plate edge marked off from the parietes less than 1.5 cm (Ricketts and Calvin 1971; by a definite change in direction of growth Kozloff 1993). lines) (Fig. 3b) (Newman 2007). The plates Color: Shell usually white, often irregular themselves include the carina, the carinola- and color varies with state of erosion. Cirri teral plates and the compound rostrum (Fig. are black and white (see Plate 11, Kozloff 3). 1993). Opercular Valves: Valves consist of General Morphology: Members of the Cirri- two pairs of movable plates inside the wall, pedia, or barnacles, can be recognized by which close the aperture: the tergum and the their feathery thoracic limbs (called cirri) that scutum (Figs. 3a, 4, 5). are used for feeding. There are six pairs of Scuta: The scuta have pits on cirri in B. glandula (Fig. 1). Sessile barna- either side of a short adductor ridge (Fig. 5), cles are surrounded by a shell that is com- fine growth ridges, and a prominent articular posed of a flat basis attached to the sub- ridge. stratum, a wall formed by several articulated Terga: The terga are the upper, plates (six in Balanus species, Fig. 3) and smaller plate pair and each tergum has a movable opercular valves including terga short spur at its base (Fig. 4), deep crests for and scuta (Newman 2007) (Figs. 2, 4, 5). depressor muscles, a prominent articular Shell: ridge, and an articular furrow (Pilsbry 1916). Shape: Shell surrounding the barna- Aperture: The shell opening, from cle body is pyramidal in shape (see Fig. 99, which the cirri emerge when feeding, is con- Kozloff 1993) (Fig. 2). trolled by movement of the terga and scuta in Basis: Calcareous and flat, attached conjunction with adductor and depressor mus- to hard substrate, rendering B. glandula a cles. When closed, plates produce a distinct sessile, or attached barnacle and sinuous line at their junction in B. glandu- (Balanomorpha). la (Kozloff 1993). Wall: Formed by the six plates (Fig. Cirri: Feathery, black and white and conspic- 2) and composed of irregular, vertical, filled uous. Each of the six pairs of legs (=cirri), tubes, giving the exterior the appearance of bears 4–7 pairs of setae (Nishizaki and Car- rough ribbing. rington 2014). The cirri of B. glandula were Longitudinal Tubes: Only the first observed to exhibit ecophenotypic present in immature individuals (Newman plasticity, where individuals adjusted re- 2007). sponse time (i.e. cirral withdrawl) to specific Plates: Calcareous, nearly habitats. An adjustment from one habitat conical and columnar. Six in family Balani- (e.g. wave-exposed) to the next (e.g. protect- dae. Each plate is composed of parietes ed) occurred over a period of two molts (exposed triangular part) (Figs. 3a, 3b), alae (approximately 18 days) (Marchinko 2003).

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected]

Hiebert, T.C. and M. Jarvis. 2015. Balanus glandula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Spe- cies, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.

Possible Misidentifications and by its unique and unusual membraneous There are three groups (i.e. superor- base. Semibalanus cariosus have terga with ders) of cirripeds including the Rhizocepha- a long pointed spur, quite different from la (parasites among crustaceans), the Acro- either B. crenatus or B. glandula. Semibala- thoracica (shell-less burrowing forms), and nus cariosus commonly co-occurs with B. the Thoracica. The Thoracica contains crenatus, B. glandula, as well as with 1,000 species worldwide including the mon- Chthamalus dalli. Juvenile S. cariosus will ophyletic taxa, Lepadomorpha, the stalked show a typical heavy ribbing and starry basis barnacles, and the Balanomorpha, or ses- outline, which would distinguish it from young sile barnacles (Perez-Losada et al. 2008; B. crenatus or B. glandula. Generally, these Chan et al. 2014). Among the sessile latter two species are found higher in the in- forms, there are four families represented tertidal than is S. cariosus, which occurs locally. The family Chthamaloidea includes mostly subtidally. members of the genus Chthamalus. Juve- Balanidae encompasses the genera nile Balanus glandula and Chthamalus dalli, Megabalanus, Paraconcavus, and Menesin- often found together, are very alike. The iella (each with one local species), Amphi- genus Chthamalus has alae on its rostral balanus (three local species) and Balanus plates, not radii (i.e. the rostral plate is (four local species). Balanus crenatus is overlapped, rather than underlapped, as in generally found in the intertidal at a lower B. glandula, by the rostrolateral plates). level than the ubiquitous and morphologically Chthamalus dalli is found both with and at similar B. glandula. Balanus glandula has no higher tide levels than B. glandula, and longitudinal wall tubes (except when young) individuals are usually brown. The family and it differs in the structure of terga and Tetraclitoidea has one species locally scuta: the terga are very wide and have (Tetraclita rubescens), and is characterized longer spurs and the scuta have no adductor by a wall that is composed of four plates ridges (compare Fig. 5 with B. glandula Figs. (rather than six in the Balanidae). 4, 5, this guide). Balanus crenatus, on the The remaining two families are the other hand, has a shell wall with a single row Balanidae and Archaeobalanidae. The Ar- of uniformly spaced tubes (Newman 2007). chaeobalanidae includes the genera Ar- Balanus crenatus is a difficult barnacle to matobalanus, Conopea, Hesperibalanus identify: "Not only does every external cha- and Semibalanus (each with one local spe- racter vary greatly in this species, but the in- cies). The latter genus includes a common ternal parts very often vary to a surprising local intertidal species S. cariosus (and for- degree, and to add to the difficulty, groups of mer member of the genus Balanus). An specimens do not rarely vary in the same isolated S. cariosus, is with splinter-like spi- manner” (Charles Darwin in Cornwall 1951). nes, nearly black cirri and is not likely to be Balanus nubilus, the giant acorn barnacle, is confused with another barnacle. It has a easily distinguished from B. glandula by its thatched appearance, being irregularly rib- large size, reaching 100 mm in diameter, and bed and its walls have uneven, longitudinal a shell aperture that is relatively large and tubes (Pilsbry 1916). However, where it is flaring (Newman 2007). Balanus trigonus is crowded or eroded, these spines may be a lower intertidal species with a southern worn off or not developed, and the barnacle distribution (to Monterey Bay, California). would have to be distinguished from other common barnacles by its terga and scuta, A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected]

Ecological Information glandula individuals showed a negative Range: Type range includes Alaska to Baja correlation in abundance with substrate California (Darwin 1854), B. glandula was temperature in the mid-intertidal (Salish Sea, introduced to South America (Argentina) and Washington, Harley 2011). Japan (Kado 2003; Newman 2007; Rashidul Associates: Forms dense clusters with Alam et al. 2014). Chthamalus dalli, Nucella, mussles and Local Distribution: Ubiquitous in a wide limpets (including Lottia digitalis) at high tide variety of locations from the open rocky levels (Kozloff 1993; Newman 2007). shores to the salty or brackish bays of the Sometimes found on larger Balanus cariosus Oregon coast (Kozloff 1993), where popula- individuals. tions show genetic heterogeneity over great Abundance: One of the most abundant ani- distances (Barshis et al. 2011), except in mals on the coast with up to 70,000 individu- central California where gene flow is more als per square meter (Ricketts and Calvin restricted between populations (Sotka et al. 1971). Larval abundance can also be high in 2004). the plankton, where 10 cyprids per 200 liters Habitat: Very adaptable to a variety of habi- were reported in central California (Gaines et tats. Suitable substrates include rocks, pil- al. 1985). ings, wood, other crustaceans, molluscs, Life-History Information and barnacles. Often in conditions with Reproduction: Cirripeds usually brood their extreme exposure to sun, wind, rain and can eggs and B. glandula produces 2–6 broods/ tolerate estuarine conditions quite well, year, in winter and spring (Oct–May in south- including those of poor water circulation, low ern California), and through September on oxygen, and little wave action (Ricketts and Vancouver Island and December in Friday Calvin 1971). Populations in polluted areas Harbor (Høeg et al. 1987). Barnacles are one have been shown to exhibit lower genetic of the few sessile organisms with internal ferti- diversity, with more individuals of the same lization and plasticity in penis length has been haplotype (southern California, Ma et al. observed, with shorter penises in high wave- 2000). energy environments (Neufeld and Palmer Salinity: Collected at salinities of 30, but 2008). Individuals are hermaphroditic and can also survive at lower salinities (Ricketts self-fertilization is possible, but not common Balanus glandula and Calvin 1971). resists (MacGinitie and MacGinitie 1949; Yonge Balanus desiccation better than other spe- 1963). Spermcast spawning can occur cies (Newman and Abbott 1980). (Barazandeh et al. 2014). Eggs and embryos Temperature: Survives a wide range of are retained in ovisacs within the mantle cavi- temperatures, but optimal temperatures for ty and are discharged as nauplii after four feeding range between 10˚ and 15˚ C months (Yonge 1963; Høeg et al. 1987; (Nishizaki and Carrington 2014). Arnsberg 2001). Ascorbic acid in water stimu- Tidal Level: One of the most important zo- lates copulation (R. Boomer personal commu- nation indicators as very small barnacles of- nication). For detailed reproductive anatomy ten settle high in the dry uppermost intertidal see Høeg et al. (1987). Littorina zone, below (Ricketts and Calvin Larva: Cirriped broods hatch as nauplius lar- 1971). Individuals are most common in the vae and undergo 4–6 naupliar stages, each high to mid-tide zone (Darwin 1854) and larger and more setose than the last (Høeg et their upper limit appears to be set by al. 1987; Arnsberg 2001; Chan et al. 2014). substrate temperature as S. cariosus and B. Hiebert, T.C. and M. Jarvis. 2015. Balanus glandula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Spe- cies, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.

Fewer setae occur on the antennae rami ling is weak and larvae stay closer to shore and mandibles in B. glandula nauplii beyond (Connolly and Roughgarden 1998; Barshis et stage I than is seen in congeners (Brown al. 2011). Most larval settlement occurs in and Roughgarden 1985). For naupliar setal spring and autumn in Friday Harbor, Was- formulae and antenna morphology, see hington (Høeg et al. 1987), but may vary with Branscomb and Vedder 1982. Larvae molt sea temperature (e.g. January–June, Santa to the second naupliar stage shortly after Barbara, California, Connell 1970). Where hatching (Branscomb and Vedder 1982). cyprids were abundant in the water column, The generalized cirriped nauplius has a tri- settlement occurred at a rate of 2 cyprids per angular or shield-shaped carapace with fron- square centimeter of available space (Gaines tolateral horns and a conspicuous naupliar et al. 1985). Like other marine invertebrate eye (Fig. 1, Arnsberg 2001; Figs. 22.1–22.2, larvae, the cyprid larvae of S. cariosus and B. Chan et al. 2014). In B. glandula, the nau- glandula become concentrated in conver- plius has curved frontal horns and a 3-lobed gence zones over internal waves, which pro- labrum (Brown and Roughgarden 1985; vides a mechanism for shoreward transport of Figs. 4 and 7, Arnsberg 2001). The first larvae prior to settlement (Shanks and Wright naupliar stage lasts less than an hour and 1987). stages 4–6 are recognizable by a pair of well Juvenile: Newly metamorphosed juveniles -developed dorsal carapace spines can be found settled in the intertidal from -0.6 (Arnsberg 2001). The sizes of B. glandula meters to -0.3 meters and have six pairs of nauplii begin at 271 µm (stage I) and end at setae situated near and around the opercular 745 µm (stage VI) (Brown and Roughgarden opening (Høeg et al. 1987). The shell wall in 1985). The final larval stage in cirripeds is juveniles consists of empty vertical tubes, called a cyprid, a non-feeding stage that at- which only become filled and irregular in the taches to a substrate by its antennae, se- adult. Individuals from the upper tidal levels cretes a cement and builds the adult calcar- reach sexual maturity and spawn during their eous shell (Ricketts and Calvin 1971). second year, while those from lower areas do Cyprids are oblong and composed of a bi- so in their first year (Yonge 1963). valve shell, six thoracic appendages, a pair Longevity: 8–10 years (Newman and Abbott of compound eyes and a conspicuous lipid 1980). reserve anteriorly (Fig. 3, Arnsberg 2001; Growth Rate: Cirriped body growth occurs in Figs. 22.2–22.3, Chan et al. 2014). Cyprids conjunction with molting (Kuris et al. 2007). prefer rough surfaces for settlement (Yonge Shell growth proceeds as follows (basal diam- 1963). Cyprid larvae in B. glandula are eters): 7–12 mm in first year, 10–16 mm by golden in color and have a distinct carapace the second year and 14–17 mm by three shape and surface that is dull and decorated years (Newman and Abbott 1980). Adults un- with papillae and four pigment patches, they der high densities form “hummocks” where are 640–780 µm in length and can be ob- individual barnacles grow tall and form tightly- served in the plankton year round except in packed columns (Bertness et al. 1998). Shell winter months (Fig. 8, Arnsberg 2001). The size (e.g. terga and scuta) may correlate with pelagic larval duration in B. glandula is esti- temperature (Barnes and Healy 1969). Those mated at 3–4 weeks (Brown and Roughgar- B. glandula that settle at lowest tidal heights den 1985). Larval settlement is effected by grow fastest in the first year, but after that, degree of coastal upwelling, where more those higher in the intertidal exhibit the fastest settlement is observed in years when upwel- growth (Yonge 1963).

Food: Filter or suspension feeders 3. BARNES, H., and M. J. R. HEALY. 1969. (Nishizaki and Carrington 2014), barnacles Biometrical studies on some common cirri- eat plankton and some detritus, that is pedes. II. Discriminate analysis of meas- strained from incoming currents by several urements on the scuta and terga of pairs of hydrostatically-extended thoracic Balanus balanus, Balanus crenatus, appendages called cirri (Fig. 1) (MacGinitie Balanus improvisus, Balanus glandula and and MacGinitie 1949). Balanus amphitrite stutrsburi, Balanus pal- Predators: Snail Nucella at low tide levels, lidus stutsburi. Journal of Experimental as well as sea stars, worms (particularly on Marine Biology and Ecology. 4:51-70. juveniles), birds and occasionally humans 4. BARSHIS, D. J., E. E. SOTKA, R. P. (e.g. Northwest Native Americas). Three KELLY, A. SIVASUNDAR, B. A. MENGE, snail species, Thais emarginata, Thais J. A. BARTH, and S. R. PALUMBI. 2011. canaliculata and Thais lamellose, are also Coastal upwelling is linked to temporal ge- common predators of B. glandula and S. netic variability in the acorn barnacle cariosus (Washington, Connell 1970). Balanus glandula. Marine Ecology Pro- Furthermore, it has been suggested that gress Series. 439:139-150. predation by this genus of drilling 5. BERTNESS, M. D., S. D. GAINES, and S. gastropods has driven the evolution of M. YEH. 1998. Making mountains out of balanomorph barnacle plate morphology barnacles: the dynamics of acorn barnacle (Palmer 1982). Predators on B. glandula hummocking. Ecology. 79:1382-1394. larvae include many plankton feeders (e.g. 6. BRANSCOMB, E. S., and K. VEDDER. fish, MacGinitie and MacGinitie 1949). 1982. A description of the naupliar stages Behavior: Adults exhibit anti-predatory hid- of the barnacles Balanus glandula ing behavior (i.e. withdrawl of cirral fan) in (Darwin), Balanus cariosus (Pallas), and response to shadow (Dill and Gillet 1991). Balanus crenatus (Bruguiere) (Cirripedia, Cyprid larvae can actively search out settling Thoracica). Crustaceana. 42:83-95. area by “walking” on antennules, and adult 7. BROWN, S. K., and J. ROUGHGARDEN. distribution is at least in part determined by 1985. Growth, morphology, and laboratory these pre-settlement behaviors and zonation culture of larvae of Balanus glandula in the plankton (Grosberg 1982; Gaines et (Cirripedia, Thoracica). Journal of Crusta- al. 1985). cean Biology. 5:574-590. 8. CHAN, B. K. K., J. T. HØEG, and R. KA- Bibliography DO. 2014. Thoracica, p. 116-124. In: Atlas 1. ARNSBERG, A. J. 2001. Arthropoda, of crustacean larvae. J. W. Margtin, J. Cirripedia: the barnacles. In: An identifi- Olesen, and J. T. Høeg (eds.). Johns Hop- cation guide to the larval marine inverte- kins University Press, Baltimore. brates of the Pacific Northwest. A. L. 9. CONNELL, J. H. 1970. A predator-prey Shanks (ed.). Oregon State University system in the marine intertidal region. I. Press. Balanus glandula and several predatory 2. BARAZANDEH, M., C. S. DAVIS, and A. species of Thais. Ecological Monographs. R. PALMER. 2014. Where even a long 40:49-78. penis can't help: evidence of long- 10. CONNOLLY, S. R., and J. ROUGHGAR- distance spermcast mating in two acorn DEN. 1998. A latitudinal gradient in north- barnacles. Journal of Experimental Ma- east Pacific intertidal community structure: rine Biology and Ecology. 454:49-54. Evidence for an oceanographically based

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