Balanoglossus gigas

Balanoglossus gigas is recorded as growing to {{Convert|1.5|m|ft}} in length, and is thus considered the largest acorn worm currently known.{{Cite journal |last=Sawaya |first=Paulo |date=5 May 1951 |title=Balanoglossus gigas Fr. Müller rediscovered on the Brazilian Coast |url=https://www.nature.com/articles/167730b0 |journal=Nature |language=en |volume=167 |issue=4253 |pages=730–731 |doi=10.1038/167730b0 |pmid=14899495 |bibcode=1951Natur.167R.730S |s2cid=2116403 |issn=1476-4687}}{{Cite book |last1=Felder |first1=Darryl L. |url=https://books.google.com/books?id=CphA8hiwaFIC&q=gigas |title=Gulf of Mexico Origin, Waters, and Biota: Biodiversity |last2=Camp |first2=David K. |date=2009 |publisher=Texas A&M University Press |isbn=978-1-60344-269-5 |language=en}} One specimen from the Brazilian coast was recorded as measuring 1.8 metres in length.{{Cite journal |last=Sawaya |first=Paulo |date=Jun 1950 |title=Re-finding of Balanoglossus gigas FR. MULLER on the brasilian sea shore |url=https://www.scielo.br/j/bipoce/a/F3zzVNWkPgKpcsVt3XwNYvB/?format=pdf&lang=pt |journal=Boletim do Instituto Paulista de Oceanografia |language=pt, en |pages=135–138 |doi=10.1590/S0100-42391950000100009 |s2cid=194068993|doi-access=free }}

When handled, B. gigas releases thick, sticky mucus with a strong smell of iodoform, which may serve as a deterrent to predators.{{Cite journal |last=Burdon-Jones |first=C. |title=The Feeding Mechanism of Balanoglossus gigas |url=https://core.ac.uk/reader/268366110 |journal=Marine Science Laboratories, Univ. Of Wales |year=1962 |volume=24 |issue=24 |page=255 |doi=10.11606/issn.2526-3382.bffclzoologia.1962.120589|doi-access=free }} The odour is caused by 2,6-dibromophenol, a phenol{{Cite web |author=((PubChem))|title=2,6-Dibromophenol |url=https://pubchem.ncbi.nlm.nih.gov/compound/11847 |access-date=2023-04-22 |website=pubchem.ncbi.nlm.nih.gov |language=en}} also reported from crustaceans, where it is the cause of a similar odour.{{Cite journal |last1=Ashworth |first1=R. B. |last2=Cormier |first2=M. J. |date=1967-03-24 |title=Isolation of 2,6-dibromophenol from the marine hemichordate, Balanoglossus biminiensis |url=https://pubmed.ncbi.nlm.nih.gov/6020478/ |journal=Science |volume=155 |issue=3769 |pages=1558–1559 |doi=10.1126/science.155.3769.1558 |issn=0036-8075 |pmid=6020478|bibcode=1967Sci...155.1558A |s2cid=24002705 }}{{Cite journal |last1=Whitfield |first1=Frank B |last2=Last |first2=John H |last3=Shaw |first3=Kevin J |last4=Tindale |first4=C Ross |date=1988 |title=2,6-Dibromophenol: The cause of an iodoform-like off-flavour in some Australian crustacea |url=https://onlinelibrary.wiley.com/doi/10.1002/jsfa.2740460104 |journal=Journal of the Science of Food and Agriculture |language=en |volume=46 |issue=1 |pages=29–42 |doi=10.1002/jsfa.2740460104|bibcode=1988JSFA...46...29W }}

Balanglossus gigas also has accumulation of iodine throughout its body, something reported from no other acorn worm or protochordate. The iodine concentration is highest in the hepatic (liver) region, and lowest in the proboscis.{{Cite journal |last1=De Jorge |first1=F. B. |last2=Sawaya |first2=Paulo |last3=Petersen |first3=J. A. |last4=Ditadi |first4=A. S. F. |date=1965-11-26 |title=Iodine: Accumulation by Balanoglossus gigas |url=https://www.science.org/doi/10.1126/science.150.3700.1182 |journal=Science |language=en |volume=150 |issue=3700 |pages=1182–1183 |doi=10.1126/science.150.3700.1182 |issn=0036-8075 |pmid=17742599 |bibcode=1965Sci...150.1182D |s2cid=42864502}}{{Cite journal |last1=De Jorge |first1=F. B. |last2=Petersen |first2=J. A. |last3=Sawaya |first3=P. |date=1967-08-01 |title=Biochemical studies on the enteropneust Balanoglossus gigas (Fr. Muller, 1898) |url=https://dx.doi.org/10.1016/0010-406X%2867%2990609-3 |journal=Comparative Biochemistry and Physiology |language=en |volume=22 |issue=2 |pages=467–475 |doi=10.1016/0010-406X(67)90609-3 |pmid=6075145 |issn=0010-406X}} Other compounds were also found to be present in accumulations in the body of B. gigas: high concentrations of calcium were found in the skeleton, while phosphate was found in the proboscis, copper in the collar and the skeleton, chloride in the collar and branchial area, iron in the hepatic region, nitrogen in the genital and hepatic regions, and a mix of sodium, calcium, potassium and magnesium found at both the front and back of the body.

A multipart study in the 1960s assessed the bioluminescence of Balanoglossus biminiensis, since synonymized with B. gigas. The reaction causing bioluminescence incorporates hydrogen peroxide and a luciferin common to balanglossids.{{Cite journal |last1=Dure |first1=Leon S. |last2=Cormier |first2=Milton J. |date=February 1963 |title=Studies on the Bioluminescence of Balanoglossus biminiensis extracts |journal=The Journal of Biological Chemistry |volume=238 |issue=2|pages=790–793 |doi=10.1016/S0021-9258(18)81336-9 |doi-access=free }}

Balanoglossus gigas are found off the coasts of the U.S. state of Georgia,{{Cite book |last=A. Sydney Johnson |first=Hilburn O. Hillestad |url=http://archive.org/details/sms-3-1974 |title=An Ecological Survey of the Coastal Region of Georgia |date=1974}} Brazil, Cuba, and in the Gulf of Mexico.{{Cite web |title=Balanoglossus gigas (Müller in Spengel, 1893) - Ocean Biodiversity Information System |url=https://obis.org/taxon/266573 |access-date=2023-04-21 |website=obis.org}} Like most acorn worms, B. gigas specimens prefer somewhat sheltered habitats with surface layers of fine sand lying above layers of fine to coarse gravel. They live in burrows with thin mucous lining on the sea floor. The burrows typically measure less than 2 cm in width and beyond 2 meters in length.

{{Reflist|refs={{Citation |title=Introduction to the Morphology, Phylogenesis, and Systematics of the Lower Deuterostomia |author-last=Godeaux |author-first=Jean E.A. |volume=8|work=Chemical Zoology|date=24 April 2014 |editor-last1=Florkin|editor-first1=Marcel|editor-last2=Scheer|editor-first2=Bradley T. |url=https://books.google.com/books?id=yrqbZbPHF1oC&dq=Balanoglossus+gigas&pg=PA643 |isbn=9780323163347|publisher=Elsevier Science |language=en}}}}{{Taxonbar|from=Q2271336}}

Category:Enteropneusta

Category:Invertebrates of Brazil

Category:Fauna of the Atlantic Ocean